CURRENT COLLECTOR AND PREPARATION METHOD THEREOF AND APPLICATION THEREFOR

Abstract

The present disclosure provides a current collector and a preparation method thereof and an application therefor. The current collector provided by the present disclosure includes a functional film layer and metal layers provided on an upper surface and a lower surface of the functional film layer, where the functional film layer includes a fire retardant. Due to an addition of the fire retardant in the functional film layer, the current collector and the preparation method thereof provided by the present disclosure can not only effectively decrease an ignition point, but also release the fire retardant from the current collector to an electrolyte at high temperature, so as to achieve an effect of active fire extinguishing and significantly improve a safety performance of a battery; the functional film layer can also carry the metal layers on the upper and lower surfaces thereon.

Claims

1. A current collector, wherein the current collector comprises a functional film layer, a metal layer provided on an upper surface of the functional film layer and a metal layer provided on a lower surface of the functional film layer; wherein the functional film layer comprises a fire retardant.

2. The current collector according to claim 1, wherein the fire retardant is selected from one or more of antimony trioxide, magnesium hydroxide, aluminum hydroxide, hydroxyl-aluminum, zinc phosphate, zinc borate, ammonium polyphosphate, tributyl phosphate, tris(2-ethylhexyl) phosphate, tris(2-chloroethyl) phosphate, tris(2,3-dichloropropyl) phosphate, tris(2,3-dibromopropyl) phosphate, cresyl diphenyl phosphate, tricresyl phosphate, triphenyl phosphate, 2-ethylhexyl diphenyl phosphate, tris(dibromopropyl) phosphate, octabromodiphenyl oxide, pentabromoethylbenzene, tetrabromobisphenol A, chlordane anhydride, cyclophosphamide polymer, melamine urate, melamine polyphosphate, pentaerythritol phosphate, and tris(2,4,6-tribromophenoxy)-triazine.

3. The current collector according to claim 1, wherein a mass of the fire retardant is 0.1%-10% of a mass of the functional film layer.

4. The current collector according to claim 1, wherein the functional film layer further comprises a polymer.

5. The current collector according to claim 4, wherein the polymer is selected from one or more of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene copolymer, polyvinyl formal, polyvinyl butyral, polyacrylonitrile, polyvinyl acetate, phenolic resin, polyurethane, polyamide, polyimide, poly-p-phenylene terephthalamide, polyterephthalate, polyethylene glycol terephthalate, polybutylene terephthalate, polycarbonate, polyphenylether, polyformaldehyde, epoxy resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, polysulfone, and polyethersulfone.

6. A preparation method of a current collector, comprising the following steps: 1) extending a slurry containing a fire retardant to obtain a functional film layer; 2) providing a metal layer on an upper surface of the functional film layer and a metal layer on a lower surface of the functional film layer to obtain a current collector.

7. The preparation method according to claim 6, wherein the slurry further comprises a polymer.

8. The preparation method according to claim 7, wherein step 1) comprises: melting and mixing the polymer and the fire retardant to obtain the slurry, extruding, stretching and cooling the slurry in turn to obtain the functional film layer.

9. The preparation method according to claim 7, wherein step 1) comprises: dissolving the polymer and the fire retardant in a solvent to obtain the slurry, coating and drying the slurry in turn to obtain the functional film layer.

10. A lithium-ion battery, comprising the current collector according to claim 1.

11. A lithium-ion battery, comprising the current collector obtained by the preparation method according to claim 6.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0048] FIG. 1 is a sectional structure diagram of a current collector provided by the present disclosure.

[0049] 1: Functional film layer; 2: Metal layer.

DESCRIPTION OF EMBODIMENTS

[0050] In order to make the object, technical scheme and advantages of the present disclosure clearer, the technical scheme in the embodiment of the present disclosure will be described clearly and completely in combination with the embodiment of the present disclosure. Obviously, the described embodiment is a part of the embodiment of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of the present disclosure.

[0051] A molecular weight of the polymer used in each embodiment of the present disclosure is as follows:

[0052] an average molecular weight of polyethylene glycol terephthalate (PET) is 31,000; an average molecular weight of polypropylene (PP) is 400,000; an average molecular weight of polybutylene terephthalate (PBT) is 38,000; an average molecular weight of polyvinylidene fluoride (PVDF) is 900,000; an average molecular weight of polyvinyl chloride (PVC) is 120,000.

[0053] The polyethylene (PE) porous membrane used in the preparation of the lithium-ion battery is wet-process polyethylene porous membrane ND12 with a thickness of 12 μm, which is produced by Shanghai Energy New Materials Technology Co., Ltd.; an electrolyte of the lithium-ion battery is LBC445B33 electrolyte of Shenzhen Capchem Technology., Ltd.

Example 1

[0054] In the current collector provided by the present embodiment, the functional film layer is obtained from 90 parts of polyethylene glycol terephthalate (PET) and 10 parts of antimony trioxide, and metal aluminum layers are provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers are provided on the upper surface and a lower surface of the functional film layer used as a negative electrode current collector material.

[0055] The current collector can be prepared according to the method as follows:

[0056] 1) 90 parts of polyethylene glycol terephthalate (PET) and 10 parts of antimony trioxide were melted and mixed at 265° C. for 20 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 1 μm.

[0057] after testing, a fire-retardant grade of the functional film layer is V1 grade, and an oxygen index is 28.

[0058] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by the vacuum evaporation method to obtain a current collector A1 with a total thickness of 5 μm used as a positive electrode current collector material;

[0059] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal copper layer with a thickness of 2 μm by the vacuum evaporation method to obtain a current collector B1 with a total thickness of 5 μm used as a negative electrode current collector material.

[0060] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of lithium cobalt oxide positive electrode, 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector Al and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0061] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B1 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Comparative Example 1

[0062] An aluminum foil current collector with a thickness of 5μm was used to replace the current collector A1, a copper foil current collector with a thickness of 5 μm was used to replace the current collector B 1. And a positive electrode sheet and a negative electrode sheet were obtained by using the same material and preparation process as in Example 1.

Comparative Example 1-2

[0063] 1) 100 parts of polyethylene glycol terephthalate (PET) was melted and mixed at 265° C. for 20 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PET film layer with a thickness of 1 μm.

[0064] 2) the upper surface and the lower surface of the PET film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by the vacuum evaporation method to obtain a current collector C1 with a total thickness of 5 μm used as a positive electrode current collector material.

[0065] the upper surface and the lower surface of the PET film layer were respectively electroplated with a metal cooper layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector D1 with a total thickness of 5 μm used as a negative electrode current collector material.

[0066] The current collector C1 was used to replace the current collector A1, the current collector D1 was used to replace the current collector B 1. And a positive electrode sheet and a negative electrode sheet were obtained by using the same material and preparation process as in Example 1.

Examples 2-1

[0067] In the current collector provided by the present embodiment, the functional film layer is obtained from 99 parts of polypropylene (PP) and 1 part of zinc phosphate, and metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer as a negative electrode current collector material.

[0068] The current collector can be prepared according to the method as follows:

[0069] 1) 99 parts of polypropylene (PP) and 1 part of zinc phosphate were melted and mixed at 170° C. for 30 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 5 μm.

[0070] after testing, a fire-retardant grade of the functional film layer is V2 grade, and an oxygen index is 26.

[0071] 2) both sides of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by the vacuum evaporation method to obtain a current collector A2-1 with a total thickness of 9 μm used as a positive electrode current collector material.

[0072] Both sides of the functional film layer were respectively electroplated with a metal copper layer with a thickness of 2 μm by the vacuum evaporation method to obtain a current collector B2-1 with a total thickness of 9 μm used as a negative electrode current collector material.

[0073] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of lithium cobalt oxide positive electrode, 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A2-1 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0074] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B2-1 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Example 2-2

[0075] In the current collector provided by the present embodiment, the functional film layer was obtained from 95 parts of polypropylene (PP) and 5 parts of zinc phosphate, metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer as a negative electrode current collector material.

[0076] The current collector can be prepared according to the method as follows:

[0077] 1) 95 parts of polypropylene (PP) and 5 parts of zinc phosphate were melted and mixed at 170° C. for 30 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 5 μm.

[0078] after testing, a fire-retardant grade of the functional film layer is V1 grade and an oxygen index is 28.

[0079] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector A2-2 with a total thickness of 9 μm used as a positive electrode current collector material.

[0080] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal copper layer with a thickness of 2 μm to obtain a current collector B2-2 with a total thickness of 9 μm used as a negative electrode current collector material.

[0081] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of lithium cobalt oxide positive electrode, 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A2-2 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0082] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B2-2 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Examples 2-3

[0083] In the current collector provided by the present embodiment, the functional film layer was obtained from 90 parts of polypropylene (PP) and 10 parts of zinc phosphate, and metal aluminum layers were provided on the upper surface and the lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer as a negative electrode current collector material.

[0084] The current collector can be prepared according to the method as follows:

[0085] 1) 90 parts of polypropylene (PP) and 10 parts of zinc phosphate were melted and mixed at 170° C. for 30 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 5 μm.

[0086] after testing, a fire-retardant grade of the functional film layer F2-3 is V0 grade, and an oxygen index is 29.

[0087] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector A2-3 with a total thickness of 9 μm used as a positive electrode current collector material.

[0088] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal copper layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector B2-3 with a total thickness of 9 μm used as a negative electrode current collector material.

[0089] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of lithium cobalt oxide positive electrode, 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A2-3 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0090] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B2-3 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Comparative Example 2-1

[0091] 1) an aluminum foil current collector with a thickness of 9 μm was used to replace the current collector A2-1, a copper foil current collector with a thickness of 9 μm was used to replace the current collector B2-1. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 2-1.

Comparative Example 2-2

[0092] 1) 100 parts of polypropylene (PP) were melted and mixed at 265° C. for 30 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PP film layer with a thickness of 5 μm.

[0093] 2) the upper surface and the lower surface of the PP film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector C2 with a total thickness of 9 μm used as a positive electrode current collector material.

[0094] the upper surface and the lower surface of the PP film layer were respectively electroplated with a metal copper layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector D2 with a total thickness of 9 μm used as a negative electrode current collector material.

[0095] The current collector C2 was used to replace the current collector A2-1, the current collector D2 was used to replace the current collector B2-1. And the positive electrode sheet and the negative electrode sheet were obtained by using the same materials and preparation process as in Example 2-1.

Example 3-1

[0096] In the current collector provided by the present embodiment, the functional film layer was obtained from 98 parts of polyethylene glycol terephthalate (PET) and 2 parts of triphenyl phosphate, and stainless-steel layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0097] The current collector can be prepared according to the method as follows:

[0098] 1) 98 parts of polyethylene glycol terephthalate (PET) and 2 parts of triphenyl phosphate were melted and mixed at 250° C. for 30 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 3 μm.

[0099] after testing, a fire-retardant grade of the functional film layer F3-1 is V1 grade, and an oxygen index is 28.

[0100] 2) the upper surface and the lower surface of the functional film layer were respectively bonded with a stainless-steel layer by a bonding method to obtain a current collector A3-1 with a total thickness of 13 μm used as a positive electrode current collector material.

[0101] the upper surface and the lower surface of the functional film layer were electroplated with a metal copper layer with a thickness of 3 μm by the electroplating method to obtain a current collect B3-1 with a total thickness of 9 μm used as a negative electrode current collector material.

[0102] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of high-nickel ternary positive electrode (NCM811), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A3-1 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0103] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of silicon carbon functional negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B3-1 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Example 3-2

[0104] In the current collector provided by the present embodiment, the functional film layer was obtained from 98 parts of polyethylene glycol terephthalate (PET) and 2 parts of triphenyl phosphate, and stainless-steel layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0105] The current collector can be prepared according to the method as follows:

[0106] 1) 98 parts of polyethylene glycol terephthalate (PET) and 2 parts of triphenyl phosphate were melted and mixed at 250° C. for 30 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 5 μm.

[0107] after testing, a fire-retardant grade of the functional film layer is V1 grade, and an oxygen index is 28.

[0108] 2) the upper surface and the lower surface of the functional film layer were respectively bonded with a stainless-steel layer with a thickness of 5 μm by a bonding method to obtain a current collector A3-2 with a total thickness of 15 μm used as a positive electrode current collector material.

[0109] the upper surface and the lower surface of functional film layer were respectively electroplated with a metal cooper layer with a thickness of 3 μm by electroplating method to obtain a current collector B3-2 with a total thickness of 11 μm used as a negative electrode current collector material.

[0110] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of high-nickel ternary positive electrode (NCM811), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methylpyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A3-2 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0111] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of silicon carbon functional negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B3-2 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Examples 3-3

[0112] In the current collector provided by the present embodiment, the functional film layer was obtained from 98 parts of polyethylene glycol terephthalate (PET) and 2 parts of triphenyl phosphate, and stainless-steel layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0113] The current collector can be prepared according to the method as follows:

[0114] 1) 98 parts of polyethylene glycol terephthalate (PET) and 2 parts of triphenyl phosphate were melted and mixed at 265° C. for 30 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 10 μm.

[0115] after testing, a fire-retardant grade of the functional film layer is V1 grade, and an oxygen index is 28.

[0116] 2) the upper surface and the lower surface of the functional film layer were respectively bonded with a stainless-steel layer with a thickness of 5 μm by a bonding method to obtain a current collector A3-3 with a total thickness of 20 μm used as a positive electrode current collector material.

[0117] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal copper layer with a thickness of 3 μm by an electroplating method to obtain a current collector B3-3 with a total thickness of 16 μm used as a negative electrode current collector material.

[0118] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of high-nickel ternary positive electrode (NCM811), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A3-3 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0119] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of silicon carbon functional negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B3-3 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Comparative Example 3-1

[0120] 1) a stainless-steel current collector with a thickness of 13 μm was used to replace the current collector A3-1, a copper foil current collector with a thickness of 9 μm was used to replace the current collector B3-1. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 3-1.

Comparative Example 3-2

[0121] 1) 100 parts of polyethylene glycol terephthalate (PET) was melted and mixed at 265° C. for 30 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PET film layer with a thickness of 3 μm.

[0122] 2) the upper surface and the lower surface of the PET film layer were respectively bonded with a stainless-steel layer with a thickness of 5 μm by a bonding method to obtain a current collector C3-1 with a total thickness of 13 μm used as a positive electrode current collector material.

[0123] the upper surface and the lower surface of the PET film layer were respectively electroplated with a metal copper layer with a thickness of 3 μm to obtain a current collector D3-1 with a total thickness of 9 μm used as a negative electrode current collector material.

[0124] The current collector C3-1 was used to replace the current collector A3-1, the current collector D3-1 was used to replace the current collector B3-1. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 3-1.

Comparative Example 3-3

[0125] 1) a stainless-steel current collector with a thickness of 15 μm was used to replace the current collector A3-2, a copper foil current collector with a thickness of 11 μm was used to replace the current collector B3-2. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 3-2.

Comparative Example 3-4

[0126] 1) 100 parts of polyethylene glycol terephthalate (PET) was melted and mixed at 265° C. for 30 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PET film layer with a thickness of 5 μm.

[0127] 2) the upper surface and the lower surface of the PET film layer were bonded with a stainless-steel layer with a thickness of 5 μm by a bonding method to obtain a current collector C3-2 with a total thickness of 15 μm used as a positive electrode current collector material.

[0128] the upper surface and the lower surface of the functional film layer were electroplated with a metal copper layer with a thickness of 3 μm by an electroplating method to obtain a current collector D3-2 with a total thickness of 11 μm used as a negative electrode current collector material.

[0129] The current collector C3-2 was used to replace the current collector A3-2, and the current collector D3-2 was used to replace the current collector B3-2. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 3-2.

Comparative Example 3-5

[0130] 1) a stainless-steel current collector with a thickness of 20 μm was used to replace the current collector A3-3, a copper foil current collector with a thickness of 16 μm was used to replace the current collector B3-3. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 3-3.

Comparative Example 3-6

[0131] 1) 100 parts of polyethylene glycol terephthalate (PET) was melted and mixed at 265° C. for 30 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PET film layer with a thickness of 10 μm.

[0132] 2) the upper surface and the lower surface of the PET film layer were bonded with a stainless-steel layer with a thickness of 5 μm by a bonding method to obtain a current collector C3-3 with a total thickness of 20 μm used as a positive electrode current collector material.

[0133] the upper surface and the lower surface of the PET film layer were respectively electroplated with a metal copper layer with a thickness of 3 μm by an electroplating method to obtain a current collector D3-3 with a total thickness of 16 μm used as a negative electrode current collector material.

[0134] The current collector C3-3 was used to replace the current collector A3-3, the current collector D3-3 was used to replace the current collector B3-3. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 3-3.

Examples 4-1

[0135] In the current collector provided by the present embodiment, the functional film layer was obtained from 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate. The metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and the metal silver layers was provided on the upper surface and lower surface of the functional film layer used as a negative electrode current collector material.

[0136] The current collector can be prepared according to the method as follows:

[0137] 1) 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate were melted and mixed at 270° C. for 25 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 3 μm.

[0138] after testing, a fire-retardant grade of the functional film layer F4 is V1 grade, and an oxygen index is 28.

[0139] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 0.1 μm by a vacuum evaporation method to obtain a current collector A4-1 with a total thickness of 3.2 μm use as a positive electrode current collector material.

[0140] the upper surface and the lower surface of the functional film layer were electroplated with a metal silver layer with a thickness of 0.1 μm by an electroplating method to obtain a current collector B4-1 with a total thickness of 3.2 μm used as a negative electrode current collector material.

[0141] After the positive and negative electrode current collector material were obtained according to the above method, 97 parts of ternary positive electrode (NCM622), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A4-1 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0142] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B4-1 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Example 4-2

[0143] In the current collector provided by the present embodiment, the functional film layer was obtained from 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate, and metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal silver layers was provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0144] The current collector can be prepared according to the method as follows:

[0145] 1) 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate were melted and mixed at 270° C. for 25 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 3 μm.

[0146] after testing, a fire-retardant grade of the functional film layer F4 is V1 grade, and an oxygen index is 28.

[0147] 2) the upper surface and the lower surface of functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 0.5 μm by a vacuum evaporation method to obtain a current collector A4-2 with a total thickness of 4 μm used as a positive electrode current collector material.

[0148] the upper surface and the lower surface of the functional film layer were electroplated with a metal silver layer with a thickness of 0.5 μm by an electroplating method to obtain a current collector B4-2 with a total thickness of 4 μm used as a negative electrode current collector material.

[0149] After the positive and negative electrode current collector material were obtained according to the above method, 97 parts of ternary positive electrode (NCM622), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A4-2 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0150] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B4-2 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Examples 4-3

[0151] In the current collector provided by the present embodiment, the functional film layer was obtained from 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate, and metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal silver layers were provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0152] The current collector can be prepared according to the method as follows:

[0153] 1) 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate were melted and mixed at 270° C. for 25 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 3 μm.

[0154] after testing, a fire-retardant grade of the functional film layer is V1 grade, and an oxygen index is 28.

[0155] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector A4-3 with a total thickness of 7 μm used as a positive electrode current collector material.

[0156] the upper surface and the lower surface of the functional film layer were electroplated with a metal silver layer with a thickness of 2 μm by a vacuum evaporation method to obtain a current collector B4-3 with a total thickness of 7 μm used as a negative electrode current collector material.

[0157] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of ternary positive electrode (NCM622), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A4-3 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0158] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B4-3 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Example 4-4

[0159] In the current collector provided by the present embodiment, the functional film layer was obtained from 99 parts of polybutylene terephthalate (PBT) and 1 part of melamine urate, and metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal silver layers were provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0160] The current collector can be prepared according to the method as follows:

[0161] 1) 99 parts polybutylene terephthalate (PBT) and 1 part of melamine urate were melted and mixed at 270° C. for 25 min to obtain a mixed slurry. The mixed slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 3 μm.

[0162] after testing, a fire-retardant grade of the functional film layer is V1 grade, and an oxygen index is 28.

[0163] 2) the upper surface and the lower surface of functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 10 μm by a vacuum evaporation method to obtain a current collector A4-4 with a total thickness of 23 μm used as a positive electrode current collector material.

[0164] The upper surface and the lower surface of the functional film layer were respectively electroplated with a metal silver layer with a thickness of 10 μm by a vacuum evaporation method to obtain a current collector B4-4 with a total thickness of 23 μm used as a negative electrode current collector material.

[0165] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of ternary positive electrode (NCM622), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A4-4 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0166] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B4-4 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Comparative Example 4-1

[0167] 1) a metal aluminum current collector with a thickness of 3.2 μm was used to replace the current collector A4-1, a copper foil current collector with a thickness of 3.2 μm was used to replace the current collector B4-1. And a positive and a negative electrode sheet were obtained by using the same material and preparation process as in Example 4-1.

Comparative Example 4-2

[0168] 1) 100 parts of polybutylene terephthalate (PBT) were melted and mixed at 270° C. for 25 min to obtain a slurry. The slurry extruded, stretched and cooled in turn to obtain a PBT film layer with a thickness of 3 μm.

[0169] 2) the upper surface and the lower surface of the PET film layer were respectively electroplated with a metal aluminum layer with a thickness of 0.1 μm to obtain a current collector C4-1 with a total thickness of 3.2 μm used as a positive electrode current collector material.

[0170] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal silver layer with a thickness of 0.1 μm to obtain a current collector D4-1 with a total thickness of 3.2 μm used as a negative electrode current collector material.

[0171] The current collector C4-1 was used to replace the current collector A4-1, the current collector D4-1 was used to replace the current collector B4-1. And the positive and the negative electrode sheet were obtained by using the same materials and preparation process as in Example 4-1.

Comparative Example 4-3

[0172] 1) a metal aluminum current collector with a thickness of 4 μm was used to replace the current collector A4-2, a copper foil current collector with a thickness of 4 μm was used to replace the current collector B4-2. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 4-2.

Comparative Example 4-4

[0173] 1) 100 parts of polyethylene glycol terephthalate (PET) was melted and mixed at 270° C. for 25 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PET film layer with a thickness of 3 μm.

[0174] 2) the upper surface and the lower surface of the PET film layer were respectively electroplated with a metal aluminum layer with a thickness of 0.5 μm by a vacuum evaporation method to obtain a current collector C4-2 with a total thickness of 4 μm used as a positive electrode current collector material.

[0175] the upper surface and the lower surface of the PET film layer were electroplated with a metal silver layer with a thickness of 0.5 μm by an electroplating method to obtain a current collector D4-2 with a total thickness of 4 μm used as a negative electrode current collector material.

[0176] The current collector C4-2 was used to replace the current collector A4-2, and the current collector D4-2 was used to replace the current collector B4-2. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 4-2.

Comparative Example 4-5

[0177] 1) a metal aluminum current collector with a thickness of 7 μm was used to replace the current collector A4-3, a copper foil current collector with a thickness of 7 μm was used to replace the current collector B4-3. And a positive electrode sheet and a negative electrode sheet were obtained by using the same material and preparation process as in Example 4-3.

Comparative Example 4-6

[0178] 1) 100 parts of polybutylene terephthalate (PBT) was melted mixed at 270° C. for 25 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PBT film layer with a thickness of 3 μm.

[0179] 2) an upper surface and a lower surface of the PBT film layer were respectively electroplated with a metal aluminum layer with a thickness of 2 μm to obtain a current collector C4-3 with a total thickness of 7 μm used as a positive electrode current collector material.

[0180] the upper and lower surfaces of the PBT film layer were electroplated with a metal silver layer with a thickness of 2 μm to obtain a current collector D4-3 with a total thickness of 7 μm used as a negative electrode current collector material.

[0181] The current collector C4-3 was used to replace the current collector A4-3, and the current collector D4-3 was used to replace the current collector B4-3. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 4-3.

Comparative Example 4-7

[0182] 1) an aluminum foil current collector with a thickness of 23 μm was used to replace the current collector A4-4, a copper foil current collector with a thickness of 23 μm was used to replace the current collector B4-4. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 4-4.

Comparative Example 4-8

[0183] 1) 100 parts of polybutylene terephthalate (PBT) was melted and mixed at 270° C. for 25 min to obtain a slurry. The slurry was extruded, stretched and cooled in turn to obtain a PBT film layer with a thickness of 3 μm.

[0184] 2) an upper surface and a lower surface of the PBT film layer were respectively electroplated with a metal aluminum layer with a thickness of 10 μm by a vacuum evaporation method to obtain a current collector C4-4 with a total thickness of 23 μm used as a positive electrode current collector material.

[0185] the upper surface and the lower surface of the PBT film layer were respectively electroplated with a metal silver layer with a thickness of 10 μm by a vacuum evaporation method to obtain a current collector D4-4 with a total thickness of 23 μm used as a negative electrode current collector material.

[0186] The current collector C4-4 was used to replace the current collector A4-4, the current collector D4-4 was used to replace the current collector B4-4. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 4-4.

Example 5

[0187] In the current collector provided by the present embodiment, the functional film layer was obtained from 99 parts of polyvinylidene fluoride (PVDF) and 1 part of tetrabromobisphenol A. The metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal nickel layers was provided on the upper surface and the lower surface of the functional film layer used a negative electrode current collector material.

[0188] The current collector can be prepared according to the method as follows:

[0189] 1) 99 parts of polyvinylidene fluoride (PVDF) were dissolved in N-methyl pyrrolidone (NMP), and then one part of tetrabromobisphenol A was added to obtain a mixed slurry. The mixed slurry was coated and dried in turn to obtain a functional film layer with a thickness of 10 μm.

[0190] after testing, a fire-retardant grade of the functional film layer F5 is 5VA grade, and an oxygen index is 78.

[0191] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 1 μm by a vacuum evaporation method to obtain a current collector A5 with a total thickness of 12 μm used as a positive electrode current collector material.

[0192] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal nickel layer with a thickness of 0.5 μm and a metal copper layer with a thickness of 0.5 μm by an electroplating method to obtain a current collector B5 with a total thickness of 12 μm used as a negative electrode current collector material.

[0193] After the positive and negative electrode current collector materials were obtained according to the above method, 97 parts of ternary positive electrode (NCM523), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A5 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0194] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of graphite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B5 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Comparative Example 5-1

[0195] 1) a metal aluminum current collector with a thickness of 12 μm was used to replace the current collector A5, a copper foil current collector with a thickness of 12 μm was used to replace the current collector B5. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 5.

Comparative Example 5-2

[0196] 1) 99 parts of polyvinylidene fluoride (PVDF) were dissolved in N-methyl pyrrolidone (NMP) to obtain a slurry. The mixed slurry was coated and dried in turn to obtain a PVDF film layer with a thickness of 10 μm.

[0197] 2) an upper surface and a lower surface of the PVDF film layer were respectively electroplated with a metal aluminum layer with a thickness of 1 μm by a vacuum evaporation method to obtain a current collector C5 with a total thickness of 12 μm used as a positive electrode current collector material.

[0198] the upper surface and the lower surface of the PVDF film layer were respectively electroplated with a metal nickel layer with a thickness of 0.5 μm and a metal copper layer with a thickness of 0.5 μm by an electroplating method to obtain a current collector D5 with a total thickness of 12 μm used as a negative electrode current collector material.

[0199] The current collector C5 was used to replace the current collector A5, the current collector D5 was used to replace the current collector B5. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 5.

Example 6

[0200] In the current collector provided by the present embodiment, the functional film layer was obtained from 99.5 parts of polyvinyl chloride (PVC) and 0.5 parts of melamine polyphosphate. The metal aluminum layers were provided on an upper surface and a lower surface of the functional film layer used as a positive electrode current collector material, and metal copper layers were provided on the upper surface and the lower surface of the functional film layer used as a negative electrode current collector material.

[0201] The current collector can be prepared as follows:

[0202] 1) 99.5 parts of polyvinyl chloride (PVC) and 0.5 parts of melamine polyphosphate were melted and mixed at 220° C. for 20 min to obtain a mixed slurry. The slurry was extruded, stretched and cooled in turn to obtain a functional film layer with a thickness of 12 μm.

[0203] after testing, a fire-retardant grade of the functional film layer is VO grade, and an oxygen index is 47.

[0204] 2) the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal aluminum layer with a thickness of 1.5 μm by a vacuum evaporation method to obtain a current collector A6 with a total thickness of 15 μm used as a positive electrode current collector material.

[0205] the upper surface and the lower surface of the functional film layer were respectively electroplated with a metal copper layer with a thickness of 1.5 μm by an electroplating method to obtain a current collector B6 with a total thickness of 15 μm used as a negative electrode current collector material.

[0206] After the positive and negative electrode current collector materials were obtained according to the above methods, 97 parts of ternary positive electrodes (NCA), 1.5 parts of acetylene black conductive agent, 1.5 parts of PVDF binder, and 60 parts of N-methyl pyrrolidone (NMP) were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector A6 and baked at 130° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required positive electrode sheet according to a conventional preparation process of the lithium-ion battery positive electrode.

[0207] According to a conventional preparation process of the lithium-ion battery negative electrode, 97 parts of silicon monoxide (20 wt %) +graphite (80 wt %) composite negative electrode, 1 part of acetylene black conductive agent, 1 part of sodium carboxymethyl cellulose (CMC), 1 part of styrene butadiene rubber (SBR) binder, and 100 parts of deionized water were stirred in a dual planet mixer under a condition of 30 r/min revolution and 1,500 r/min rotation for 4 h in vacuum to form a uniform slurry, then the slurry was coated on the current collector B6 and baked at 100° C. for 30 min to dry, rolled under 40 tons of rolling pressure and cut into a required negative electrode sheet.

Comparative Example 6-1

[0208] 1) a metal aluminum current collector with a thickness of 15 μm was used to replace the current collector A6, a copper foil current collector with a thickness of 15 μm was used to replace the current collector B6. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 6.

Comparative Example 6-2

[0209] 1) 99.5 parts of polyvinyl chloride (PVC) was melted and mixed at 220° C. for 20 min to obtain a slurry. And the slurry was extruded from an extruding equipment. A PVC film layer with a thickness of 12 μm was obtained by extruding, stretching and cooling in turn.

[0210] 2) the upper surface and the lower surface of the PVC film layer was respectively electroplated with a metal aluminum layer with a thickness of 1.5 μm by a vacuum evaporation method to obtain a current collector C6 with a total thickness of 15 μm used as a positive electrode current collector material.

[0211] the upper surface and the lower surface of the PVC film layer were respectively electroplated with a metal cooper layer with a thickness of 1.5 μm by an electroplating method to obtain a current collector D6 with a total thickness of 15 μm used as a negative electrode current collector material.

[0212] The current collector C6 was used to replace the current collector A6, the current collector D6 was used to replace the current collector B6. And the positive electrode sheet and the negative electrode sheet were obtained by using the same material and preparation process as in Example 6.

[0213] The lithium-ion batteries are prepared from the positive electrode sheet and negative electrode sheet of the above Examples and the Comparative Examples. Specifically, the lithium-ion batteries are prepared by combining the positive electrode sheet and negative electrode sheet with polyethylene (PE) porous membrane and lithium-ion battery electrolyte through a conventional preparation process of the lithium-ion battery.

[0214] After fully charged the lithium-ion battery obtained in the above Examples and Comparative Examples, three safety tests of acupuncturing, heating and overcharging of the batteries are tested, 10 batteries in each group are tested in parallel, and the pass rate is calculated. The test method refers to GB/T 31485-2015 standard, and the test results are shown in Table 1.

TABLE-US-00001 TABLE 1 Safety test results of the lithium-ion batteries provided by the Examples and Comparative Examples Pass rate of Pass rate of Pass rate of acupuncturing (%) heating (%) overcharging (%) Example 1 100% 100% 100% Comparative  0  0  0 Example 1-1 Comparative  10%  20%  20% Example 1-2 Example 2-1 100%  80%  90% Example 2-2 100%  90% 100% Example 2-3 100% 100% 100% Comparative  0  0  0 Example 2-1 Comparative  10%  10%  10% Example 2-2 Example 3-1 100%  80%  80% Example 3-2 100% 100% 100% Example 3-3 100% 100% 100% Comparative  0  0  0 Example 3-1 Comparative  10%  10%  10% Example 3-2 Comparative  10%  0  0 Example 3-3 Comparative  20%  10%  10% Example 3-4 Comparative  10%  0  0 Example 3-5 Comparative  30%  20%  20% Example 3-6 Example 4-1 100%  90% 100% Example 4-2 100% 100% 100% Example 4-3 100%  90%  90% Example 4-4  80%  70%  80% Comparative  0  0  0 Example 4-1 Comparative  30%  10%  20% Example 4-2 Comparative  0  0  0 Example 4-3 Comparative  20%  10%  20% Example 4-4 Comparative  0  0  0 Example 4-5 Comparative  10%  0  10% Example 4-6 Comparative  0  0  0 Example 4-7 Comparative  10%  0  0 Example 4-8 Example 5 100% 100% 100% Comparative  10%  0  10% Example 5-1 Comparative  30%  10%  20% Example 5-2 Example 6 100% 100% 100% Comparative  0  0  0 Example 6-1 Comparative  10%  0  0 Example 6-2

[0215] It can be seen from Table 1 that, the safety performance of lithium-ion battery prepared by the current collector of the present disclosure has been significantly improved, especially the pass rate of safety performance tests such as acupuncturing, heating and overcharging has been significantly improved.

[0216] Finally, it should be explained that the above embodiments are only used to illustrate the technical scheme of the present disclosure, rather than limit it; although the present disclosure is described in detail with reference to the above embodiments, those ordinary skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or substitute some or all of them with the same technical features; these modifications or substitutions do not make the essence of the corresponding technical scheme depart from the scope of the technical schemes of the embodiments of the present disclosure.