PACKAGING MATERIAL FOR BATTERY, SOFT PACK BATTERY AND BATTERY THERMAL CONTROL DEVICE

Abstract

Provided is a battery packaging material for packaging a battery, in particular a packaging material for a soft pack battery used in a vehicle and a soft pack battery thermal management system. With regard to the defect of an insufficient corrosion resistance of a battery packaging material in the prior art, particularly provided is a solution of an aluminum plastic composite film for packaging a battery as follows: that is to say, a battery packaging material, and the battery packaging material comprises an aluminum foil layer and a plastic layer compounded on the surface of the aluminum foil layer, wherein the aluminum foil layer is formed from an aluminum alloy with corrosion resistance to cooling water.

Claims

1. A battery packaging material formed of a metal-plastic composite film, comprising a metal foil layer and a plastic layer laminated to the inner surface of the metal foil layer, wherein the plastic layer is laminated only on the inner side of the metal foil layer.

2. The battery packaging material according to claim 1, which is an aluminum plastic film comprising an aluminum foil layer and a plastic layer laminated on the inner surface of the aluminum foil layer, wherein, the aluminum foil layer is a single-layer aluminum foil, and the aluminum foil layer is formed of an aluminum alloy that is resistant to cooling water or an antifreeze solution; and the aluminum alloy that is resistant to cooling water is selected from 3 series aluminum alloy or 1 series aluminum alloy.

3. The battery packaging material according to claim 1, which is an aluminum plastic film comprising an aluminum foil layer and a plastic layer laminated on the inner surface of the aluminum foil layer; wherein the aluminum foil layer is a composite layer aluminum foil, the aluminum foil layer includes a core material and a skin material located on the outside of the core material, the corrosion potential of the skin material of the aluminum foil layer is lower than the corrosion potential of the core material.

4-5. (canceled)

6. The battery packaging material according to claim 3, wherein the core material of the composite layer aluminum foil is a 1 series aluminum alloy or an 8 series aluminum alloy, and the skin material of the composite layer aluminum foil is formed by adding 1% to 10% by mass of zinc element on the basis of a 1 series aluminum alloy or an 8 series aluminum alloy.

7. The battery packaging material according to claim 18, wherein the aluminum foil in the aluminum plastic film or the aluminum plastic film has a stamping depth value or cupping value of more than 5 mm.

8. The battery packaging material according to claim 1, wherein the plastic layer is laminated only on the inner side of the aluminum foil layer, and the inner plastic layer is a thermoplastic resin film.

9. The battery packaging material according to claim 1, wherein the aluminum plastic film or its aluminum foil has an OY aqueous solution corrosion resistant life of more than 500 hours.

10. The battery packaging material according to claim 1, which is formed by compounding a metal foil and a thermoplastic resin film inside the metal foil; wherein, the metal foil is a single-layer metal of stainless steel foil, or the metal foil is a composite layer metal foil containing a core material and a skin material located on the outside of the core material, and the corrosion potential of the skin material is lower than the corrosion potential of the core material.

11. A soft-pack battery comprising an electrode material and an electrolyte, and a battery packaging material according to claim 1 for external packaging, the soft-pack battery body has the following resistance to coolant corrosion: the corrosion resistance test method is an OY aqueous solution corrosion test; the body of the soft-pack battery is soaked in an aqueous solution, and the corrosion resistance life of the soft-pack battery in the above test is greater than 500 hour, and the plastic layer on the inner surface of the metal foil layer isolates the electrolyte from the metal foil layer.

12. (canceled)

13. A soft-pack battery thermal control device, wherein the soft-pack battery is packaged using the battery packaging material comprising a metal foil layer and a plastic layer laminated to the inner surface of the material foil layer, wherein the plastic layer on the inner surface of the metal foil layer isolates the soft-pack battery electrolyte from the metal foil layer, the soft-pack battery is capable of direct heat exchange with a water-based coolant.

14. The soft-pack battery thermal control device of claim 13 further comprising a partition and a water-based coolant, at least part of the surface of the partition is in direct contact with at least part of the outer surface of the soft-pack battery, and a fluid passage is provided in the partition, a plurality of soft-pack batteries constitute a battery unit, and the battery units are spaced from the partition, the water-based coolant flows in the fluid passage in the partition, and the water-based coolant directly contacts the soft pack battery for heat exchange.

15. The soft-pack battery thermal control device according to claim 14, wherein the partition is made of a metal material, the corrosion potential of the partition is equal to or less than the corrosion potential of the aluminum foil in the aluminum plastic film, or the corrosion potential of the partition is equal to or less than the corrosion potential of the skin material of the aluminum foil of the aluminum plastic film.

16. (canceled)

17. The battery packaging material according to claim 6, wherein the composite layer aluminum foil is heated at a high temperature, and a zinc element in the skin material gradually diffuses toward the core material, thus from the outside to the inside of the aluminum foil layer, the zinc content continuously changes, and the corrosion potential continuously changes, avoiding the zinc element content and the corrosion potential cliff-like change or abrupt change, which is more conducive to the transformation of corrosion morphology into uniform layer corrosion.

18. The soft-pack battery thermal control device according to claim 13, wherein the soft-pack battery is packaged using the battery packaging material which is an aluminum plastic film comprising an aluminum foil layer and a plastic layer laminated on the inner surface of the aluminum foil layer, wherein, the aluminum foil layer is a single-layer aluminum foil, and the aluminum foil layer is formed of an aluminum alloy or pure aluminum that is resistant to cooling water or an antifreeze solution; and the aluminum alloy that is resistant to cooling water or antifreeze is selected from 3 series aluminum alloy or 1 series aluminum alloy.

19. The soft-pack battery thermal control device according to claim 13, wherein the soft-pack battery is packaged using the battery packaging material which is an aluminum plastic film comprising an aluminum foil layer and a plastic layer laminated on the inner surface of the aluminum foil layer; wherein the aluminum foil layer is a composite layer aluminum foil, the aluminum foil layer includes a core material and a skin material located on the outside of the core material, the corrosion potential of the skin material of the aluminum foil layer is lower than the corrosion potential of the core material.

20. The soft-pack battery thermal control device according to claim 19, wherein the core material of the composite layer aluminum foil is a 1 series aluminum alloy or an 8 series aluminum alloy, and the skin material of the composite layer aluminum foil is formed by adding 1% to 10% by mass of zinc element on the basis of a 1 series aluminum alloy or an 8 series aluminum alloy.

21. The soft-pack battery thermal control device according to claim 20, wherein the composite layer aluminum foil is heated at a high temperature, and a zinc element in the skin material gradually diffuses toward the core material, thus from the outside to the inside of the aluminum foil layer, the zinc content continuously changes, and the corrosion potential continuously changes, avoiding the zinc element content and the corrosion potential cliff-like change or abrupt change, which is more conducive to the transformation of corrosion morphology into uniform layer corrosion.

22. The soft-pack battery thermal control device according to claim 13, wherein the soft-pack battery is packaged using the battery packaging material which is formed by compounding a metal foil and a thermoplastic resin film inside the metal foil; wherein, the metal foil is a single-layer metal of stainless steel foil, or the metal foil is a composite layer metal foil containing a core material and a skin material located on the outside of the core material, and the corrosion potential of the skin material is lower than the corrosion potential of the core material.

23. The soft-pack battery thermal control device according to claim 13, wherein the plastic layer is laminated only on the inner side of the metal foil layer, and the inner plastic layer is a thermoplastic resin film.

Description

DESCRIPTION OF THE DRAWINGS

[0090] FIG. 1 is a schematic view of the structure of the first aluminum plastic film;

[0091] FIG. 2 is a schematic structural view of a second aluminum plastic film;

[0092] FIG. 3 is a schematic view of an application of a battery using the aluminum plastic film of the present invention;

[0093] FIG. 4 is a schematic diagram of a soft pack battery;

[0094] FIG. 5 is a schematic diagram of a soft-pack battery thermal control device;

[0095] FIG. 6 is a schematic view of a third structure of aluminum plastic film;

[0096] FIG. 7 shows the comparison of corrosion resistance of single-layer aluminum alloy (left) and composite-layer aluminum alloy (right);

[0097] FIG. 8 shows fin partitions in the form of staggered serrated fins. The fin partition includes a plurality of tooth-shaped units, and the same row of tooth-shaped units communicate with each other to form a fluid passage, and the adjacent tooth-shaped units are staggered one after the other. The top and bottom planes of the toothed units are in direct contact with the battery.

[0098] FIG. 9 is a fin partition in the form of a straight fin. It includes parallel risers and upper and lower plates connected to both ends of the risers. The plate is in direct contact with the battery, and fluid channels are formed between the risers.

DESCRIPTION OF EMBODIMENTS

[0099] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention includes but is not limited thereto.

Embodiment 1

[0100] As shown in FIG. 1, an aluminum plastic film is provided. The aluminum plastic film includes an aluminum foil layer 1 and plastic layers 2 and 3 laminated on both surfaces of the aluminum foil layer. Wherein, the aluminum foil layer 1 is formed by compounding a 3 series aluminum alloy aluminum foil layer 7 (core material) and a 7 series aluminum alloy aluminum foil layer 6 (skin material). For example, a 3003 aluminum alloy and a 7072 aluminum alloy composite are used, and a 7072 aluminum alloy layer 6 is composited on the outside of the 3003 aluminum alloy layer 7. Alternatively, the aluminum plastic film is formed by sequentially stacking a heat seal layer, a 3003 aluminum foil layer, a 7072 aluminum foil layer, and a nylon layer, wherein the aluminum foil layer and the plastic layer are adhered with a conventional adhesive. In other words, the aluminum plastic film is composed of a heat seal layer, an adhesive layer, a 3003 aluminum foil core layer, a 7072 aluminum foil skin layer, an adhesive layer, and a nylon protective layer.

[0101] The corrosion potential of the 3003 aluminum alloy is approximately 0.72V, and the corrosion potential of the 7072 aluminum alloy is approximately 0.88V. Since the corrosion potential of the 7072 aluminum alloy is lower than the corrosion potential of the 3003 aluminum alloy, the 7072 aluminum alloy acts as a sacrificial anode and protects the core material from corrosion when in contact with the coolant. The thickness of the heat seal layer is preferably 80-100 m, the thickness of the nylon protective layer is preferably 20-30 m, and the thickness of the composite aluminum foil layer is preferably 200-300 m. Wherein, the thickness of the 7-series aluminum alloy layer 6 preferably accounts for 10% of the entire aluminum foil layer 1. Similarly, the adhesive between the inner and outer plastic layers 2 and 3 and the aluminum foil layer 1 is bonded by the adhesive 4 and 5, respectively.

[0102] In addition, the state of the heat treatment of the aluminum foil layer may be O state, H14 state, or H16 state, among which O state is preferable.

[0103] The aluminum foil layer in this embodiment is thicker than the aluminum foil layer in the conventional aluminum plastic film, which is not only favorable for long-term resistance to the corrosion of the antifreeze but also is favorable for the vapor barrier property of the aluminum plastic film, thereby ensuring the long-term reliability of the soft packet battery packaging.

Embodiment 2

[0104] The structure of the present embodiment is substantially similar to that of Embodiment 1, and the aluminum alloy layer 1 is also formed by the composite of the core material 7 and the skin material 6, and the skin material 6 is an anode protection layer. In contrast, the 7023 aluminum alloy is replaced with a zinc-added 3003 aluminum alloy (3003+1% Zn or 3003+1.5% Zn in the following table) as a sacrificial anode layer. The potential of 3003+1% Zn is about 0.83V to 0.89V, and the potential is lower than that of the 3003 core material.

TABLE-US-00001 TABLE 1 Alloy Chemical Composition chemical composition % other Alloy Si Fe Cu Mn Zn Zr single total the rest 3003 0.6 0.7 0.05-0.2 1.0-1.5 0.1 / 0.05 0.15 Al 3003 + 0.6 0.7 0.05-0.2 1.0-1.5 0.5-1.5 / 0.05 0.15 Al 1% Zn 3003 + 0.6 0.7 0.05-0.2 1.0-1.5 1.0-2.0 / 0.05 0.15 Al 1.5% Zn

Embodiment 3

[0105] A second type of aluminum plastic film is provided as shown in FIG. 2. The aluminum plastic film includes an aluminum foil layer 1 and a thermoplastic resin film layer 3 integrated inside the aluminum foil layer. The aluminum foil layer is a composite layer aluminum foil. The aluminum foil layer includes a core material and a skin material located on the outside of the core material. The corrosion potential of the skin material of the aluminum foil layer is lower than the corrosion potential of the core material. Further, the core material of the aluminum foil layer is formed of a corrosion-resistant aluminum alloy or pure aluminum. For example, the composite aluminum foil layer 1 is formed by compounding a 3-series aluminum foil layer 7 (e.g., 3003) and a 7-series aluminum foil layer 6 (e.g., 7072). The thermoplastic resin film layer 3 (also called the heat seal layer 3, such as CPP) is laminated only on the inner side of the aluminum foil layer 1, without the need for an outer nylon protective layer.

[0106] The thickness of the heat seal layer 3 (CPP) is preferably 30-50 m, and the thickness of the entire composite aluminum foil layer 1 is preferably 200 m. Wherein, the 7-series aluminum alloy layer 6 is compounded on the outside as a sacrificial anode; the thickness of the 7-series aluminum alloy preferably accounts for 10% of the entire aluminum foil layer 1. When used as a soft-pack battery packing material and the battery is immersed in cooling water, the 7-series aluminum alloy acts as a water-contact layer. Similarly, the inner thermoplastic resin film layer 3 and the aluminum foil layer 1 are adhesively bonded by an adhesive 5 commonly used for aluminum plastic films. The soft pack battery made of the aluminum plastic film provided above can be immersed in the coolant for a long time, and has a long-term resistance to the corrosion of the coolant.

Embodiment 4

[0107] The structure of this embodiment is substantially similar to that of embodiment 3, and 3003 aluminum alloy is also used for the core material layer. The difference is that the skin material is changed from a 7-series aluminum foil layer to a metal zinc layer, and the thickness of the metal zinc layer may preferably be 10-20 m, which may be formed by a zinc spray process. Since the potential of this metal zinc is lower than that of the aluminum alloy core material, it can be used as a sacrificial anode to protect the core material from corrosion. And zinc metal can effectively prevent aluminum alloy core pitting corrosion.

Embodiment 5

[0108] This embodiment describes a battery using the above-mentioned aluminum plastic film and an application mode of the battery. A soft-pack battery is provided which comprises an electrode material and a polymer electrolyte and an aluminum plastic film for external packaging. Wherein, the soft-pack battery is covered with an aluminum plastic film containing a composite layer aluminum foil with a sacrificial anode function, such as the composite layer aluminum foil in embodiment 1 or 3, that is, the aluminum foil uses a 3003 aluminum alloy as core material and is externally compounded with a 7072 aluminum alloy as skin material. After the soft pack battery is packaged with the above aluminum plastic film that is resistant to corrosion by the antifreeze coolant, the soft pack battery may be soaked in the antifreeze coolant so that it can directly exchange heat with the antifreeze coolant. As shown in FIG. 3, after the soft pack battery 11 is sealed with the main board 13 through the top edge 112, the body of the soft pack battery 11 is immersed in the antifreeze coolant. In this way, the heat exchange effect of the battery is better, and the temperatures in the upper and lower parts of the battery are more uniform.

Embodiment 6

[0109] This embodiment adopts an aluminum plastic film structure similar to that of Embodiment 1, except that the adhesive for bonding the nylon protective layer is a release agent that facilitates separation. That is, the nylon protective layer is similar to the release film. In this way, the nylon layer can protect the aluminum foil layer during the deep drawing process of the aluminum plastic film; after deep drawing, the nylon layer can be easily separated from the aluminum foil layer, thereby forming an aluminum plastic film similar to that in Embodiment 3.

Embodiment 7

[0110] The aluminum plastic film described in this embodiment is formed by compounding a thermoplastic resin film (ie, a heat seal layer such as polypropylene) and a composite layer aluminum alloy foil. The core material layer 7 of the aluminum foil layer uses AA1050 pure aluminum, and the skin material 6 is formed of an aluminum alloy to which 4%-7% zinc element is added based on pure aluminum 1050 (simplified as AA1050+4-7% Zn). The corrosion potential of the skin material is negative to the core material, and the skin material is used as a sacrificial anode protection core material, and the skin material composite ratio is preferably 102%. The heat treatment state of the composite layer aluminum foil is an annealed state (O state), and the thickness is preferably 100-300 m, more preferably 200-300 m. The composite layer aluminum foil not only has excellent resistance to coolant corrosion, but also has good ductility and deep drawing performance.

[0111] The aluminum plastic film or its aluminum foil is required to have better ductility and deep drawing performance. According to the standard test of GB/T 4156-2007 Metallic Sheets and Thin-Band Erickson Cupping Tests, the cupping value of the aluminum plastic film or its aluminum foil is preferably more than 5 mm, more preferably more than 10 mm.

[0112] The aluminum plastic film or its aluminum foil is required to have better resistance to coolant corrosion. Corrosion resistance test method uses the OY water solution corrosion test commonly used in the aluminum heat transmission industry of heat exchangers. The specific test method may also refer to the corrosion test of the OY aqueous solution in Embodiment 1 of CN201080021209.6. The OY water corrosion test is roughly as follows:

[0113] OY aqueous solution components: chloride ion (CD: 1951 mg/L, sulfate ion (SO.sub.4.sup.2): 600.2 mg/L, iron ion (Fe.sup.3+): 300.1 mg/L, copper ion (Cu.sup.2+): 10.01 mg/L. The pH of the OY aqueous solution is about 3 (the pH of the aqueous solution in the OY test described in the present invention is about 3 unless otherwise specified).

[0114] OY aqueous solution temperature: 88 C., stirring at 0.6-0.9 m/s (200 rpm) for 8 hours, then standing for 16 hours; the above cycle is repeated.

[0115] In the above OY aqueous solution corrosion test, any perforation near 5 mm of the edge of the aluminum foil is ignored. When corrosion piercing occurs at any point except the edge 5 mm in the aluminum foil, the accumulated corrosion test time is the corrosion life of the aluminum foil in the OY aqueous solution. Experiments show that the corrosion resistance life of the aluminum foil in the embodiment of the present invention is greater than 1000 hours.

[0116] Above, the corrosion life of aluminum plastic film or its aluminum foil can also be evaluated by its anti-corrosion service life when it is immersed in antifreeze on a real car, such as aluminum plastic film that has a service life of more than 5 years. It is preferably more than 10 years, more preferably more than 15 years.

Embodiment 8

[0117] As shown in FIG. 4 and FIG. 5, the battery thermal control device described in this embodiment employs the above soft pack battery that can be directly immersed in a coolant (such as a coolant mainly composed of ethylene glycol and water) for a long period of time. The soft-pack battery thermal control device includes a soft-pack battery 11 and a water-based coolant. The outer package of the soft-pack battery 11 is in direct contact with a coolant, and the soft-pack battery 11 is packaged by any of the above-mentioned packaging materials resisted by a coolant (such as aluminum plastic film that is resistant to water-based coolant corrosion). The thermal control device also includes a partition 12 that is preferably a staggered saw-tooth fin partition as shown in FIG. 8, or a flat fin partition as shown in FIG. 9. At least part of the surface of the partition 12 is in direct contact with at least part of the outer surface of the soft-pack battery 11. In addition, a fluid passage 121 is provided in the partition 12. The fluid channel 121 is in direct contact with the battery 11, and the cooling water in the fluid channel 121 is in direct contact with the battery 11 for heat exchange. A soft pack battery 11 constitutes one battery unit (of course, two soft pack batteries can also be used to form one battery unit), and the battery unit is spaced from the partition 12. The partition serves as a support for the soft pack battery on the one hand and as forming coolant flow field on the other.

[0118] The aluminum plastic film seals the periphery of the battery core, and only the battery electrode or the electrode connection port protrudes from the aluminum plastic film. The battery thermal control device further includes a main board 13, and the main board 13 is provided with a socket. A portion of the battery protruding from the aluminum film (ie, positive and negative electrode tabs 111) is inserted into the main board 13 through the socket. Preferably, part of the top edge 112 of the battery is also inserted into the main board 13 through the socket.

[0119] The battery thermal control device also includes an outer housing 14. The interior of the outer housing 14 is provided with an accommodating chamber, and a plurality of the battery units and the partition 12 are integrated into the accommodating chamber of the outer housing 14. The outer housing 14 also includes a fluid inlet and a fluid outlet (not shown in the drawings).

[0120] The main board 13 is located in the accommodation chamber of the outer housing 14, and separates the accommodation chamber into two parts. The first portion houses the battery unit body and the partition 12, and the second portion receives the electrode and/or electrode connection port portion protruding from the aluminum plastic film. The physical isolation is between the first part and the second part.

[0121] The battery thermal control device also includes a coolant. The coolant is water, a mixed liquid containing ethylene glycol and water, a mixed liquid containing propylene glycol and water, or an antifreeze coolant.

[0122] Preferably, the partition 12 is made of a metal material, and the corrosion potential of the partition 12 is negative to the corrosion potential of the aluminum foil in the aluminum plastic film. For example, AA1050 aluminum alloy is used as the packaging material metal foil, and AA1050+5% Zn is used as the partition 12. Alternatively, the corrosion potential of the partition 12 is lower than that of the aluminum foil of the aluminum plastic film. For example, the packaging material metal foil is AA1050/AA1050+5% Zn alloy, and the partition 12 is AA1050+7% Zn. In this way, the partition can also play an anodic protective function, further preventing the battery from corroding and failing.

Embodiment 9

[0123] This embodiment is the same as the aluminum foil used in Embodiment 7. The difference is that aluminum foil and aluminum plastic film excellent in molding property (or deep drawing property) are evaluated and selected as follows.

[0124] Follow the steps A-F below to perform the molding performance test and evaluation:

[0125] A, Teflon core material, mold size 34 mm44 mm, rounded R=0.6 mm. According to the test requirements, adjust the forming depth of the press forming tester to a value between 5.0 mm and 15.0 mm. Adjust the compressed air pressure so that the mold side pressure is greater than or equal to 3.0 MPa.

[0126] B, take the surface smooth, clean, no wrinkle sample film, cut a width of not less than 100 mm, a length of not less than 200 mm film for testing.

[0127] C. Place the CPP surface of the film toward the core and place it in the press-molding tester. Ensure that the film is smooth and wrinkle-free, and the amount of side lamination film is sufficient.

[0128] D. Press the button to perform stamping. Carefully remove the sample after the stamping is complete.

[0129] E. Combining the CPP surface of the stamped sample with the CPP surface of the unpressed molded sample. Ensure that the sample is flat and free of distortion. Heat sealing is carried out along the edge of the stamping molding not more than 2 mm. The heat sealing conditions were: heat sealing temperature of 190 C. (uniform heating up and down), heat sealing pressure of 0.2 MPa, and heat sealing time of 6 seconds.

[0130] F. Visually inspect the stamped sample after heat sealing to check whether the sample has cracked or delaminated.

[0131] As can be seen from the above method, the depth of molding of the aluminum plastic film of the present invention is greater than 5.0 mm. More preferably, an aluminum plastic film or aluminum foil having a forming depth greater than 10.0 mm is selected.

Embodiment 10

[0132] This embodiment is the same as the aluminum foil used in Embodiment 7. The difference is that instead of using the OY test to evaluate, the corrosion life of aluminum foils for aluminum plastic film is evaluated using the Internal Corrosion Performance Test in Section 5.14 of the QC/T 468-2010 standard.

[0133] Wherein, the corrosion resistance test in section 5.14 of the QC/T 468 standard is roughly as follows:

[0134] Test temperature: 88 C.

[0135] Mixed solution flow: 1.3-1.6 L/s (liters per second)

[0136] Mixture:

[0137] Antifreeze model: 45% ethylene glycol antifreeze, freezing temperature: 30 C.

[0138] ASTM water: 1 L (liter) of distilled water contains 148 mg (milligrams) of sodium sulfide, 165 mg of sodium chloride, and 138 mg of sodium bicarbonate.

[0139] Mixing ratio: 40% antifreeze+60% ASTM water.

[0140] The experimental results show that the corrosion life of the aluminum foil of the present invention is greater than 1000 hours.

Embodiment 11

[0141] The core and skin materials of the composite layer aluminum alloy can be selected from the following Table 2 options 1 to 4:

TABLE-US-00002 Core Options Skin material composition (weight percentage) material Option1 Zn (4~7%) + Si (0.5~1.0%) + Ti (0.1~0.2%) + AA1050 Fe (0.5~1.5%) + Al (the rest) Option2 Zn (4~7%) + Si (0.5~1.0%) + Ti (0.1~0.2%) + Fe (0.5~1.5%) + Sm (0.1~0.3%) + Al (the rest) Option3 Zn (4~7%) + Si (0.5~1.0%) + Ti (0.1~0.2%) + AA1050 + Sm Fe (0.5~1.5%) + Al (the rest) (0.1%~0.3% Option4 Zn (4~7%) + Si (0.5~1.0%) + Ti (0.1~0.2%) + weight Fe (0.5~1.5%) + Sm (0.1~0.3%) + Al (the rest) percentage)
Using the method of Embodiment 7, the corrosion life of the aluminum foil of the present embodiment is more than 1000 hours, and even more than 1500 or 2000 hours.

Embodiment 12

[0142] This embodiment provides an aluminum plastic film comprising an aluminum foil layer and a plastic layer laminated on the surface of the aluminum foil layer. The aluminum foil layer is a composite layer aluminum foil. The aluminum foil layer includes a core material and a skin material located on the outside of the core material. The corrosion potential of the skin material of the aluminum foil layer is lower than the corrosion potential of the core material. Wherein, the skin material located on the outside of the core material is formed by two layers of skin materials or more than two layers of multilayer skin materials, and the corrosion potential is reduced from the inside to the outside.

[0143] For example, the aluminum foil layer from the inside to the outside is the core material, the first layer of skin material, the second layer of skin material. The core material is AA1050 aluminum alloy. The first skin material is AA1050 plus 2% Zn aluminum alloy, and the second skin material is AA1050 plus 4% Zn aluminum alloy. Therefore, the corrosion potential is: core material>first skin material>second skin material. This can further ensure that the corrosion is lamellar corrosion, thereby further avoiding pitting corrosion and ensuring battery safety.

Embodiment 13

[0144] This embodiment provides another corrosion-resistance test of the aluminum plastic film aluminum foil of the soft-packaged battery outer package, that is, the anti-freezing solution corrosion test method of the soft-packaged battery. This test method is used to evaluate and determine the anti-freeze fluid corrosion life of the product.

[0145] Bodies of several identical soft-pack batteries are immersed in the following mixed solution. The positive and negative poles of the soft pack battery are vertically upwards, and the immersion height of the mixed solution is flush with the lower edge of the top edge of the soft pack battery.

[0146] Mixed solution composition: Consisting of 40% volume ratio antifreeze and 60% ASTM solution. The antifreeze is 45% ethylene glycol antifreeze, and the freezing temperature is minus 30 degrees Celsius; the ASTM solution consists of 1 liter of distilled water and 148 milligrams of sodium sulfate, 165 milligrams of sodium chloride and 138 milligrams of sodium bicarbonate.

[0147] Mixed solution temperature: 902 degrees Celsius. The mixed solution flows in a horizontal direction parallel to the largest surface of the battery body, and the flow rate through the surface of the battery body is 0.5 m/s.

[0148] The test is run at the above temperature and flow rate for 76 hours, and the standstill is allowed to stand for 8 hours as one cycle. Solution pH check and rehydration during shutdown. Solution check includes pH check and visual inspection. No pH change of 1 is allowed during the test. The appearance of the solution does not allow turbidity and sedimentation.

[0149] The corrosion depth of the aluminum foil in the aluminum plastic film can be checked at any time during the test. The corrosion depth value of all corrosion points is counted. If the maximum value is greater than 10% of the original thickness of the aluminum foil, the moment when the maximum reaches 10% of the original thickness of the foil is recorded. The accumulated test time is defined as the corrosion life of the aluminum foil in the aluminum plastic film, that is, the corrosion life resistance of the anti-freeze liquid of the soft-pack battery. Therefore, the so-called lifetime in the test method of the present embodiment is the accumulated test time to reach the above-mentioned corrosion depth value.

[0150] In the above tests, the above description of the present invention shall prevail in different places. Other places may refer to the Chinese automobile industry standard QC/T 468-2010. It should be noted that the aluminum plastic film of the outer package of the soft-pack battery of the present invention is preferably an aluminum plastic film composed of aluminum foil and a thermoplastic resin film compounded on the inside of the aluminum foil. The outer side of the aluminum foil is free of other plastic layers. Therefore, the aluminum foil is in direct contact with the antifreeze solution at the beginning. However, the aluminum plastic film for the outer package of the soft-pack battery of the present invention may also be (although not preferred) an aluminum plastic film composed of an aluminum foil, a thermoplastic resin film laminated on the inner side of the aluminum foil, and a heat-resistant resin film laminated on the outer side of the aluminum foil. A typical heat-resistant resin film (such as PA or PET) is easily swollen by antifreeze. Therefore, in order to harmonize the test standards, the heat-resistant resin film outside the aluminum plastic film is peeled off before performing the above-described corrosion life test, and then the above corrosion test is performed.

[0151] For the convenience of brief description, the present invention defines the corrosion resistance test of the aluminum foil in the above-mentioned aluminum plastic film as the specific antifreeze corrosion life test for a soft-pack battery.

[0152] In order to meet the automotive durability requirements of the components, select those soft pack batteries that have a lifetime value greater than 336 hours in the specific antifreeze corrosion life test for a soft-pack battery. Since the power battery is very demanding on safety, a soft pack battery of more than 500 hours is preferable, and a soft pack battery of more than 1000 hours is more preferable; further, it is preferably a soft pack battery of more than 2000 hours. Still further preferred is a soft pack battery that is greater than 5000 hours.

[0153] As another assessment method is provided as follows, in the above specific antifreeze corrosion life test for a soft-pack battery, the test time is fixed at 14 days (ie, 336 hours). Check the depth of pitting everywhere, where the maximum pitting depth requirement is less than 50% of the original foil thickness. It is preferably less than 20%, more preferably less than 10%; further preferably less than 8%; and even more preferably less than 5%. In other words, the maximum pitting depth is 20% to 50% of the original thickness of the aluminum foil, or more than 10% and less than 20%, or more than 0% and less than 10%.

[0154] In order to have the above-mentioned corrosion resistance, the aluminum foil in the aluminum plastic film needs to have a suitable aluminum alloy material composition and a suitable thickness.

[0155] The aluminum foil material that satisfies the above corrosion resistance requirements can be selected from the following materials: single-layered 1 series aluminum alloy (pure aluminum), or composite layer aluminum alloy with sacrificial anode protection.

[0156] The thickness of the aluminum foil that satisfies the above requirements for corrosion resistance can be selected from the following thicknesses: 120-300 microns.

[0157] For example, a pure aluminum AA1050 with a thickness of more than 150 m, or a composite aluminum alloy with a thickness of 100 m of AA1050 and 20 m of AA7072 (ie, a composite layer aluminum alloy with a total thickness of 120 m). The use of the above two kinds of aluminum foils for the manufacture of aluminum plastic film and soft pack battery can meet the anti-freezing fluid corrosion life requirements above, so as to meet the automotive life requirements.

Embodiment 14

[0158] This embodiment describes an aluminum plastic film in which aluminum foil is compositely formed of a core material and an outer skin material, wherein, the core material is formed of an 8-series aluminum alloy (such as 8079 or 8021) of 100 micrometers to 300 micrometers. The outer skin material is formed by adding 2%-6% by mass of zinc element on the basis of the 8 series aluminum alloy (as described in Table 3 below). The composite rate is 10%-20%. The aluminum plastic film containing this composite aluminum alloy has good corrosion resistance and deep drawability. When tested according to the method of Embodiment 7, the corrosion resistant life is greater than 1300 hours.

TABLE-US-00003 TABLE 3 element Si Fe Cu Zn Al the other Mass 0.05-0.30 0.70-1.3 0.05 2.0-6.0 the rest 0.15 percentage

Embodiment 15

[0159] This embodiment describes an aluminum plastic film in which aluminum foil is compositely formed of a core material and an outer skin material. The core material is formed of a 1-series aluminum alloy (such as 1050) of 100 m to 300 m. The outer skin material is formed by adding 2%-6% by mass of zinc element on the basis of the 1 series aluminum alloy (as described in Table 4). The composite rate is 10%-20%.

Embodiment 16

[0160] The core material is formed of a 1-series aluminum alloy (e.g., 1050) of 100 m to 300 m, and the outer skin material is formed by adding 2%-6% by weight of zinc element on the basis of the 1 Series aluminum alloy (as shown in Table 4). The aluminum plastic film containing this composite aluminum alloy has a good resistance to electrolyte corrosion and good resistance to cooling water corrosion. Tested according to the method of Embodiment 7, its corrosion life is greater than 1800 hours.

TABLE-US-00004 TABLE 4 Element Si Fe Cu Mn Mg Zn V Ti Al Other Weight 0.25 0.40 0.05 0.05 0.05 2.0-6.0 0.05 0.03 the rest 0.03 percentage

Embodiment 17

[0161] An aluminum plastic film is provided, the aluminum plastic film comprising an aluminum foil layer and a plastic layer compounded on the surface of the aluminum foil layer, wherein the aluminum foil layer material is a 3003 aluminum alloy.

[0162] Referring to FIG. 6, the aluminum plastic film is composed of an outer protective layer 2, an aluminum foil layer 1, and an inner heat sealing layer 3 from the outside to the inside. The outer protective layer 2 uses nylon (ON). The inner heat seal layer 3 is a cast polypropylene film (CPP). The inner heat-seal layer 3 also serves as an insulation to maintain electrical insulation between the aluminum foil layer 1 and the internal electrolyte. The outer protective layer 2, the inner heat-seal layer 3 and the aluminum foil layer 1 are respectively bonded by the adhesives 4, 5. The outer protective layer 2 serves to protect the aluminum foil layer 1 during deep drawing. The adhesive layer is composed of any of the following resins, which are polyester-urethane resins, polyether-urethane resins, isocyanate resins, and unsaturated carboxylic acid-grafted polyolefin resins.

[0163] In the above, the aluminum foil layer 1 can also be replaced with other rust-proof aluminum, such as 5 series anti-rust aluminum or other 3 series anti-rust aluminum. More specific examples are: 3004, 3005, 3105, 5052, 5086, etc. Aluminum foil layer 1 can also be replaced with 6 series aluminum alloy, such as 6063. Of course, the aluminum foil layer may also be pure aluminum, which is a 1050 aluminum alloy, or a 1060 aluminum alloy, or an 1100 aluminum alloy, or an improved version based on the above-described basic model of pure aluminum. These pure aluminum also have good corrosion resistance.

[0164] The soft-packed battery formed by the aluminum plastic film can be directly immersed in the coolant and has a long-term corrosion resistance to the coolant, wherein the coolant is preferably a water-based coolant containing ethylene glycol and/or propylene glycol. During the formation of the soft-packed battery, a deep-drawing process is required, and the outer protective layer 2 provides protection to the aluminum foil layer 1 during this deep-drawing process. After the soft pack battery is immersed in the coolant for a period of time, the nylon layer 2 may swell and dissolve and peel, but this does not affect the insulation, sealability and long-term corrosion resistance of the aluminum plastic film. Since the aluminum plastic film of the soft-pack battery has a long-term resistance to the corrosion of the coolant, the soft-pack battery can be directly immersed in the coolant for cooling. The beneficial effect of this is that the heat exchange efficiency of the soft pack battery is very high, and it will not be overheated even when working with high current, which can increase the power density and reliability of the entire battery system.

[0165] Compared to 8 series aluminum alloys, 3 series or 5 series rust prevention aluminum have better resistance to corrosion resistance of antifreeze, and its corrosion resistance is longer and more reliable.

Embodiment 18

[0166] This embodiment describes the use of the aluminum plastic film wrapped soft-packaged polymer lithium-ion battery described in Embodiment 17. This embodiment is substantially the same as embodiment 5. The difference is that the aluminum foil in the aluminum plastic film used for packaging soft-pack batteries is formed of a single-layered aluminum alloy, which is formed of a rust-proof aluminum foil, such as 3003 aluminum foil.

Embodiment 19

[0167] This embodiment describes the use of the aluminum plastic film described in Embodiment 17 to wrap the soft polymer lithium ion battery. This embodiment is substantially the same as embodiment 5. The difference is that the aluminum foil in the aluminum plastic film used for packaging the soft-pack battery is formed of a single-layer aluminum alloy. The single-layer aluminum alloy is formed from a 1 series aluminum alloy foil, such as an O-state 1050 aluminum foil or other pure aluminum.

Embodiment 20

[0168] This embodiment describes an aluminum plastic film in which aluminum foil is compositely formed of a core material and an outer skin material. Wherein the core material is formed of an 8-series aluminum alloy (such as 8079 or 8021) of 150 micrometers to 300 micrometers, and the outer skin material is made of a 7 series aluminum alloy (such as 7072), and the composite ratio is taken as 20% to 50%. Further, the 8 series aluminum alloy and the 7 series aluminum alloy are composited and then heated or annealed so that the Zn element appropriately diffuses to form a gradient potential change. The aluminum plastic film containing such a composite aluminum alloy has relatively good corrosion resistance and deep drawability. According to the method of Embodiment 7, it has a corrosion-resistant life of more than 1,500 hours.

Embodiment 21

[0169] This embodiment describes an aluminum plastic film formed by bonding a thermoplastic film (such as CPP), an aluminum foil layer, and a Teflon film from the inside to the outside. Because the Teflon film has good water and corrosion resistance, the soft pack battery made of the aluminum plastic film can be immersed in water or antifreeze solution for a long time.

Embodiment 22

[0170] Reference may be made to Embodiment 7, but the pH of the OY aqueous solution selected in this embodiment is approximately 11. This embodiment is the same as Embodiment 7 except that the pH of the OY aqueous solution is different from that of Embodiment 7. In the embodiment of the present invention, an aluminum foil with a corrosion-resistant life of more than 1,000 hours is selected for the aluminum plastic film for battery packaging materials.

Embodiment 23

[0171] In this embodiment, a corrosion resistance comparison test is performed on a single layer of 1050 aluminum alloy and a composite layer aluminum alloy (core material is 1050 aluminum alloy, and the skin material is a sacrificial layer having a relatively negative potential) in an OY experiment.

[0172] The antifreeze system is selected for OY experiments. The experimental time is 4 weeks. After the experiment, the surface of the material is immersed in nitric acid to remove corrosion products, as follows:

[0173] As shown in FIG. 7, after a 4-week OY test in an antifreeze system, the left picture shows that the AA1050 single-layer aluminum alloy has obvious pitting corrosion and pitting corrosion is serious. The right picture shows that there is no obvious pitting on the aluminum alloy surface of the composite sacrificial layer. It can be seen that the occurrence of pitting corrosion can be effectively suppressed by compounding the skin material with a negative corrosion potential on the surface of the aluminum alloy core material. After heat-sealing the inner plastic layer of the aluminum plastic film formed of the aluminum foil of the above composite layer, the corrosion resistance time of the aluminum foil-resistant cooling water can meet the automotive requirements. At the same time, since the core material inside the aluminum foil is pure aluminum, its electrolyte corrosion resistance is also superior to the traditional iron-aluminum alloy, thereby ensuring the battery life and safe use.

[0174] The specific embodiments of the present invention have been described in detail above, but these are only embodiments, and the present invention is not limited to the above-described specific embodiments. Any equivalent modifications and substitutions made to the present invention by those skilled in the art are also within the scope of the present invention. Therefore, all equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the scope of the present invention.