Battery Cell, Manufacturing Method Thereof, and Direct Water-Cooling Battery Module Comprising the Same

Abstract

The present invention relates to a battery cell, a manufacturing method thereof, and a battery module comprising the same, and a battery cell related to one example of the present invention comprises an electrode assembly, a case accommodating the electrode assembly, a plating layer formed on an outer surface of the case, a scratch region formed by removing a partial region of the plating layer, and a porous coating layer provided to surround the scratch region and containing a sacrificial material having a higher metal ionization tendency than that of the plating layer.

Claims

1. A battery cell comprising: an electrode assembly; a case accommodating the electrode assembly therein; a plating layer disposed on an outer surface of the case; a scratch region of the plating layer comprising plated portions and non-plated portions where a partial region of the plating layer has been removed; and a porous coating layer surrounding the scratch region and containing a sacrificial metal having a metal ionization tendency that is higher than a metal ionization tendency of the plating layer.

2. The battery cell according to claim 1, wherein the plated portions are areas in which the plating layer remains between two adjacent ones of the non-plated portions.

3. The battery cell according to claim 2, wherein a partial region of the porous coating layer contacts the outer surface of the case at the non-plated portions of the plating layer.

4. The battery cell according to claim 2, wherein in the porous coating layer, a thickness of a region surrounding the plated portions of plating layer is smaller than a thickness of a region surrounding the non-plated portions of the plating layer in the scratch region.

5. The battery cell according to claim 1, wherein the porous coating layer has a structure of the sacrificial metal is sprayed onto the scratch region.

6. The battery cell according to claim 1, wherein the plating layer is a nickel-plating layer, and the sacrificial metal is one or more selected from the group consisting of: aluminum, magnesium, zinc, an aluminum alloy, a magnesium alloy, or a zinc alloy.

7. The battery cell according to claim 1, wherein the scratch region has a structure of the plating layer is-subjected to scratch treatment by a laser.

8. The battery cell according to claim 1, further comprising a waterproof sheet surrounding the porous coating layer, the waterproof sheet including a polymer film.

9. A battery module comprising: a plurality of battery cells each being the battery cell according to claim 1; a cell frame accommodating the plurality of battery cells therein spaced apart from each other, the cell frame configured to receive a flow of cooling water between the plurality of battery cells; and a cooling water supply part configured to supply the cooling water into the cell frame, wherein the cooling water supply part is configured to supply cooling water without insulating treatment.

10. A method for manufacturing the battery cell according to claim 1, comprising: a step (a) of forming the scratch region of the plating layer provided on the outer surface of the case; and a step (b) of forming the porous coating layer covering the scratch region by spraying the molten sacrificial metal onto the scratch region together with compressed air.

11. The method for manufacturing the battery cell according to claim 10, wherein the non-plated portions are formed by removing the partial region of the plating layer leaving the plated portions where the plating layer remains between two adjacent ones of the non-plated portions, and the porous coating layer is formed so that at least a partial region of the porous coating layer contacts the outer surface of the case at the non-plated portions of the plating layer.

12. The method for manufacturing the battery cell according to claim 10, wherein the compressed air is sprayed at a pressure ranging from 12000 psi to 16000 psi.

13. The method for manufacturing the battery cell according to claim 10, wherein the compressed air is sprayed at a rate ranging from 2000 m/s to 2200 m/s.

14. The method for manufacturing the battery cell according to claim 10, wherein during the step (a), the scratch region is formed by removing the partial region of the plating layer using a laser.

15. The method for manufacturing the battery cell according to claim 10, further comprising a step of heat-shrinking a waterproof film on the case so that the porous coating layer is not exposed to an outside of the battery cell.

Description

DESCRIPTION OF DRAWINGS

[0038] FIG. 1 is a schematic configuration diagram of a conventional battery module.

[0039] FIG. 2 schematically illustrates a configuration diagram of a direct water-cooling battery module according to one example of the present invention.

[0040] FIGS. 3 to 5 schematically illustrate cross-sectional diagrams of a battery cell according to one example of the present invention.

[0041] FIGS. 6 to 10 are diagrams for explaining a manufacturing method of a battery cell according to one example of the present invention.

[0042] FIG. 11 is a schematic diagram showing a thermal spray coating device used in a battery cell manufacturing method.

MODE FOR INVENTION

[0043] Hereinafter, a battery cell (hereinafter, also referred to as a direct water-cooling battery cell) according to one example of the present invention, a manufacturing method thereof, and a direct water-cooling battery module (hereinafter, also referred to as a battery module) comprising the same will be described in detail with reference to the drawings.

[0044] In addition, regardless of the reference numerals, the same or corresponding components are given by the same or similar reference numerals, duplicate descriptions thereof will be omitted, and for convenience of explanation, the size and shape of each component member as shown can be exaggerated or reduced.

[0045] FIG. 2 schematically illustrates a configuration diagram of a direct water-cooling battery module (100) according to one example of the present invention, and FIGS. 3 to 5 schematically illustrate cross-sectional diagrams of a battery cell (120) according to one example of the present invention.

[0046] Specifically, FIG. 3 shows a case in a state provided with a scratch region, FIG. 4 shows a case in a state where a porous coating layer is formed, and FIG. 5 shows a case in a state provided with a waterproof sheet covering the porous coating layer.

[0047] As shown in FIG. 2, the direct water-cooling battery module (100) according to one example of the present invention comprises a cell frame (110), at least one direct water-cooling battery cell (120), and general coolant (W).

[0048] Referring to FIG. 2, the battery module (100) according to one example of the present invention comprises a plurality of battery cells (120), a cell frame (110) accommodating the plurality of battery cells (120), and a cooling water supply part (160).

[0049] Specifically, the battery module (100) comprises a plurality of battery cells (120), a cell frame (110) provided so that the plurality of battery cells (120) is disposed apart from each other, and cooling water (W) allows to flow between the plurality of battery cells (120), and a cooling water supply part (160) for supplying cooling water (W) into the cell frame (110).

[0050] The battery module (100) may have a direct water-cooling structure directly cooling the battery cell (120) through cooling water (W).

[0051] Referring to FIG. 2, the cell frame (110) has a predetermined space part therein, and is provided in a structure in which cooling water (W) can flow within the space part. The cooling water (W) may be supplied to the inner space part of the cell frame (110), and then discharged to the outside of the cell frame (110). To this end, the battery module (100) may comprise a cooling water discharge part for discharging the cooling water (W) to the outside of the cell frame (110). In addition, the cooling water supply part (160) may comprise a cooling water storage tank and a pump. In addition, the cooling water supply part (160) may be provided to supply cooling water (W) that is not insulated. The general cooling water (W) may be cooling water generally used in vehicles.

[0052] Referring to FIGS. 3 to 5, the battery cell (120) according to one example of the present invention comprises an electrode assembly (127), a case (121), a plating layer (122), a scratch region(S) provided on the plating layer (122), and a porous coating layer (123) surrounding the scratch region(S).

[0053] In addition, the battery cell (120) may comprise a waterproof sheet (125) including a polymer film and provided to surround the porous coating layer (123).

[0054] The battery cell (120) comprises an electrode assembly (127), a case (121) accommodating the electrode assembly (127), a plating layer (122) formed on an outer surface of the case (121), a scratch region(S) formed by removing a partial region of the plating layer (122), and a porous coating layer (123) provided to surround the scratch region(S) and containing a sacrificial metal having a higher metal ionization tendency than that of the plating layer (122).

[0055] Referring to FIG. 2, when the direct water-cooling battery cell (120) is immersed in the cooling water (W), the moisture may be transferred to the porous coating layer (123). At this time, the sacrificial metal of the porous coating layer (123) can improve the corrosion resistance of the case (121) because the ionization reaction of the metal to moisture is greater than the metal ionization reaction to moisture in the case (121).

[0056] In addition, when the direct water-cooling battery cell (120) is immersed in the cooling water (W), the moisture of the cooling water (W) is subjected to ionization reaction with the sacrificial metal of the porous coating layer due to the difference in metal ionization reaction between the case (121) and the porous coating layer (123), and as a result, the metal ionization reaction of the case (121) is suppressed, whereby the direct water-cooling battery cell (120) can prevent corrosion of the case (121).

[0057] The electrode assembly (127) is accommodated in the case (121), and comprises a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The electrode and the separator may constitute an integrated electrode assembly (127). For example, the electrode assembly (127) may be a jelly-roll type electrode assembly in which sheet-type positive and negative electrodes are wound in a state where a separator is interposed therebetween, a stack type electrode assembly in which pluralities of positive and negative electrodes are sequentially stacked in a state where a separator is interposed therebetween, or a stack/folding type electrode assembly in which unit cells obtained by stacking positive and negative electrodes in predetermined units in a state where a separator is interposed therebetween are sequentially wound in a state where they are positioned on a separation film.

[0058] In addition, the case (121) serves to accommodate the electrode assembly (127), and to protect the battery cell (120) from external impacts. The case (121) may be cylindrical, pouch, or angular, and for example, the case (121) may be cylindrical. In particular, the electrode assembly (127) may be a rolled jelly-roll type electrode assembly, the case (121) may be a cylindrical case, and the direct water-cooling battery cell (120) may be a cylindrical battery cell.

[0059] Also, the case (121) may be formed of a metal material, and the case (121) may be formed of one or more selected from the group consisting of steel or stainless steel.

[0060] In addition, the surface of the case (121) may be nickel (Ni)-plated. That is, the plating layer (122) may comprise a nickel-plating layer.

[0061] Meanwhile, the nickel-plating layer has little discoloration, excellent rust resistance force, and excellent corrosion resistance and wear resistance. However, due to material characteristics, the nickel-plating layer may be corroded when immersed in cooling water, and as the corrosion progresses, polarity is generated and simultaneously insulation properties are deteriorated.

[0062] Meanwhile, when the porous coating layer (123) is provided on the plating layer (122), the plating layer (122) may be a factor that hinders the movement of electrons between the porous coating layer (123) and the case (121).

[0063] The scratch region(S) is formed on the plating layer (122), and then the porous coating layer (123) is coupled to the scratch region(S), whereby electron movement between the porous coating layer (123) and the case (121) can be made smoothly.

[0064] Also, the scratch region(S) may also be formed by removing a partial region of the plating layer (122) along the thickness direction of the plating layer (122), and the scratch region(S) may be formed up to a partial region of the plating layer (122) along the thickness direction of the plating layer (122), and an outer surface of the case facing the partial region.

[0065] Referring to FIG. 3, the scratch region(S) may comprise a plurality of non-plated portions (122b) that a partial region of the plating layer (122) has been removed and a plated portion (122a) in which the plating layer remains between two adjacent non-plated portions (122b). Also, the non-plated portion (122b) may mean a region where the outer surface of the case (121) is exposed to the outside because there is no plating layer in the relevant region. In addition, the scratch region(S) may be formed in a partial region of the plating layer (122).

[0066] The scratch region(S) is a region where the plating layer (122) of the case (121) has been partially removed according to a predetermined pattern. In addition, the scratch region(S) may be provided as the plating layer (122) is subjected to scratch treatment by a laser. Alternatively, the scratch region(S) may also be provided as the plating layer (122) is subjected to etching treatment.

[0067] Referring to FIG. 4, the porous coating layer (123) surrounds the plating layer (122) and the scratch region(S), and at least a partial region is inserted into the scratch region(S).

[0068] Also, the porous coating layer (123) may be provided so that as at least a partial region is inserted into the scratch region(S), it contacts the outer surface of the case (121) through the non-plated portions (121b).

[0069] In addition, in the porous coating layer (123), the thicknesses (t) of the region surrounding the plating layer (122) and the region surrounding the scratch region(S) may be different. In the porous coating layer (123), the thickness of the region surrounding the plating layer (122) may be smaller than the thickness of the region surrounding the scratch region(S).

[0070] The porous coating layer (123) is formed of a sacrificial metal material with a greater ionization tendency than that of the case (121). The sacrificial metal may contain one or more selected from the group consisting of aluminum, magnesium, zinc, an aluminum alloy, a magnesium alloy, and a zinc alloy.

[0071] Since the ionization tendency of the sacrificial metal is greater than the ionization reaction of steel or stainless steel, which is the material of the case (121), the moisture in the general cooling water (W) performs the ionization reaction with the sacrificial metal in the porous coating layer (123) before the ionization reaction with the case (121).

[0072] In addition, the porous coating layer (123) may be formed as the sacrificial metal is sprayed onto the scratch region(S).

[0073] As one example, the porous coating layer (123) may be coated on the outer surface of the case (121) using a thermal spray coating method. The porous coating layer (123) may have a porous structure as the molten sacrificial metal is sprayed into the case (121) together with compressed air. The porous coating layer (123) may have a pore size of 1 m to 10 m.

[0074] In addition, as the porous coating layer (123) formed of the sacrificial metal has a porous structure, it has an effect of increasing the contact area with moisture and air, and the sacrificial metal, which has a higher ionization tendency than that of the case, first reacts with moisture.

[0075] Referring to FIG. 5, the waterproof sheet (125) surrounds the outer surface of the case (121) so that the porous coating layer (123) is not exposed to the outside. The waterproof sheet (125) may comprise a polymer film. In a state where the case is surrounded by the polymer film, the waterproof sheet (125) may be heat-compressed to the case (121) by heat-shrinking the polymer film.

[0076] The heat-shrinkable polymer film may comprise one or more selected from the group consisting of polyvinylchloride (PVC), polypropylene (PP), or polyethylene terephthalate (PET).

[0077] Referring to FIG. 2, the battery module (100) may comprise a waterproof layer (130, 140) provided inside the cell frame (110), and provided to cover the upper end and the lower end of the battery cell (120), respectively. The waterproof layer (130, 140) performs a function of preventing moisture from permeating into the case (121) and fixing the battery cell (120) to the cell frame (110).

[0078] An upper waterproof layer (130) may be provided on the upper end of the case (121), and a lower waterproof layer (140) may be provided on the lower end of the case (121). In addition, the upper end side, and the lower end side of the battery cell (120) may be integrally fixed to the inner surface of the cell frame (110) through the waterproof layer (130, 140), respectively.

[0079] In addition, the waterproof layer (130, 140) may comprise a waterproof adhesive or a potting resin, and the potting resin may be any one of a silicone-based resin, a urethane-based resin, and an epoxy-based resin.

[0080] FIGS. 6 to 10 are diagrams for explaining a manufacturing method of a battery cell according to one example of the present invention, and FIG. 11 is a schematic diagram showing a thermal spray coating device used in a battery cell manufacturing method. In addition, FIG. 7 is a cross-sectional diagram taken along the line a-a in FIG. 6(b), and FIG. 9 is a cross-sectional diagram taken along the line b-b in FIG. 6(d).

[0081] As described above, the porous coating layer (123) may be coated on the outer surface of the case (121) using a thermal spray coating method.

[0082] Also, the method for manufacturing the battery cell related to one example of the present invention comprises a step (a) of forming the scratch region on the plating layer provided on the outer surface of the case, and a step (b) of forming the porous coating layer covering the scratch region by spraying the molten sacrificial metal onto the scratch region together with compressed air.

[0083] In addition, the scratch region(S) may be formed to comprise a plurality of non-plated portions that a partial region of the plating layer (122) is removed and a plated portion in which the plating layer remains between two adjacent non-plated portions.

[0084] Furthermore, the porous coating layer (123) may be formed so that at least a partial region contacts the outer surface of the case (121) through the non-plated portions.

[0085] Referring to FIGS. 6 and 7, a plate (P) having a metal material is prepared. The plate (P) may be formed of one or more selected from the group consisting of steel or stainless steel. The plate (P) is processed into a case (121), and a plating layer (122) is formed on one side (the outer surface of the case) of the plate (P).

[0086] The plating layer (122) is formed by plating a plating material (e.g., nickel) onto one side of the plate (P).

[0087] Referring to FIG. 6(a), one plate (P) is divided into several unit regions (A1 to A4). Here, the respective unit regions (A1 to A4) constitute unit plates that are processed into the case (121), respectively. That is, each unit region has a size that can be manufactured to the case (121). In this example, for convenience of explanation, the respective unit regions virtually partitioned on the plate (P) are separately referred to as a first unit region (A1) to a fourth unit region (A4).

[0088] Referring to FIGS. 6(c) and 6(d), the respective unit regions are cut along cutting lines (Lc), thereby being divided into unit plates (P), and referring to FIG. 6(e), the respective unit plates (P1) may each be processed into a cylindrical shape to be and manufactured into a case (121).

[0089] Referring to FIG. 6(b), scratch regions (S1 to S4) are provided in the respective unit regions (A1 to A4), respectively.

[0090] The scratch regions (S1 to S4) are regions where the plating layer (122) of the case (121) is subjected to etching treatment by a chemical method according to a predetermined scratch pattern (Ls, see FIG. 8), or the plating layer (122) is scratched by a laser. In the scratch region(S), the outer surface (non-plated portion) of the case (121) is provided to be exposed to the outside.

[0091] In addition, the scratch region(S) is provided in each unit region (A1 to A4). In this document, the scratch regions(S) of the respective unit regions (A1 to A4) are separately referred to as a first scratch region (S1) to a fourth scratch region (S4).

[0092] Here, the first scratch region (S1) is a region where in the first unit region (A1), the plating layer (122) is damaged, and the second scratch region (S2) is a region where in the second unit region (A2), the plating layer (122) is damaged.

[0093] Also, the third scratch region (S3) is a region where in the third unit region (A3), the plating layer (122) is damaged, and the fourth scratch region (S4) is a region where in the fourth unit region (A4), the plating layer (122) is damaged.

[0094] In addition, the first scratch region (S1) to the fourth scratch region (S4) are provided on the same plane of the plate (P), which may be spaced apart from each other.

[0095] Furthermore, each scratch region (S1 to S4) may have a smaller area than that of each unit region (A1 to A4).

[0096] Referring to FIG. 8, the unit plate (P1) may have a scratch pattern (Ls), where the scratch pattern may be any one of a regular grid pattern (see FIG. 8(a)), a diagonal grid pattern (see FIG. 8(b)), a wave pattern (see FIG. 8(c)), a horizontal straight pattern (see FIG. 8(d)), or a vertical straight pattern (see FIG. 8(e)).

[0097] According to this scratch pattern, the scratch region(S) may comprise a plurality of non-plated portions that a partial region of the plating layer (122) is removed therefrom and a plated portion in which the plating layer remains between two adjacent non-plated portions.

[0098] The scratch region(S) in each unit plate (P1) may also be provided to be surrounded by an edge region (E) of the unit plate (P1), or may also be provided on the entire region of one side of the unit plate (P1). The edge region (E) is a region where the non-plated portion of the plating layer (122) is not exposed to the outside and only the plated portion is exposed to the outside.

[0099] Referring to FIGS. 9 and 11, the thermal spray coating device (200) sprays the molten sacrificial metal (M) onto one side of the plate (P), on which the scratch region(S) is provided, together with compressed air (Ac). Referring to FIG. 10, the sacrificial metal (M) forms a porous coating layer (123) surrounding the scratch region (S1).

[0100] Referring to FIG. 11, the thermal spray coating device (200) comprises a metal spray part (210), an air spray part (220), a guide part (240), and a heating part (250).

[0101] The guide part (240) supplies a sacrificial metal wire (231) to the metal spray part (210), and is installed in an entry path through which the sacrificial metal wire (231) enters the metal spray part (210). The guide part (240) may comprise a pair of guide rolls (241, 242). The pair of guide rolls (241, 242) allows the sacrificial metal wire (231) to enter a passage (211) of the metal spray part (210), and guides the movement of the sacrificial metal wire (231), while rotating in opposite directions.

[0102] The metal spray part (210) is electrically connected to the heating part (250). The heating part (250) applies a voltage to the metal spray part (210).

[0103] Also, the metal spray part (210) is provided with a passage (211) through which the sacrificial metal wire (231) passes. The sacrificial metal wire (231) is melted while passing through the heated metal spray part (210).

[0104] In addition, depending on the type of sacrificial metal, the heating temperature of the metal spray part (210) may vary. For example, the melting temperature of aluminum (A1) is approximately 660 C., and the melting temperature of magnesium (Mg) is approximately 650 C.

[0105] The air spray part (220) sprays compressed air (Ac). The air spray part (220) may be installed inside the metal spray part (210). The air spray part (220) may be disposed in the metal spray part (210) such that the central axis of the outlet of the air spray part (220) is coaxial with the central axis of the outlet of the metal spray part (210).

[0106] In addition, the compressed air (Ac) is sprayed from the thermal spray coating device (200) together with the molten sacrificial metal (M). The compressed air (Ac) may be sprayed at a pressure ranging from 12,000 psi to 16,000 psi, and the compressed air (Ac) may be sprayed at a rate ranging from 2,000 m/s to 2,200 m/s.

[0107] The molten sacrificial metal (M) flows along the passage (211) of the metal spray part (210) to be discharged to the outside of the metal spray part (210), and is sprayed onto the plate (P) by the compressed air (Ac) discharged from the air spray part (220).

[0108] The molten sacrificial metal (M) is sprayed onto the scratch region(S) together with compressed air (Ac), and plated on the plate (P) so that the non-plated portion of the scratch region(S) is not exposed to the outside.

[0109] Referring to FIG. 9, the thermal spray coating device (200) may spray the molten sacrificial metal (M) into the first scratch region (S1), and this process may be performed for each of the second unit region (A2) to the fourth unit region (A4).

[0110] The porous coating layer (123) is formed as the molten sacrificial metal (M) is sprayed onto the outer surface of the case (121) together with high-pressure compressed air (Ac). Accordingly, the bonding force between the porous coating layer (123) and the case (121) can be increased. That is, as the molten sacrificial metal (M) particles are sprayed onto the outer surface of the case (121) together with high-pressure compressed air (Ac), the porous coating layer (123) may be formed.

[0111] Through such a process, as shown in FIG. 6(c), a plurality of porous coating layers (123) covering the first scratch region (S1) to the fourth scratch region (S4), respectively may each be provided in one plate (P).

[0112] One plate (P) is cut for each unit region (A1 to A4) along the cutting lines (Lc), thereby forming a plurality of unit plates (P1). The unit plate (P1) provided with the porous coating layer (123) is processed into a cylindrical shape, and manufactured into a cylindrical case (121).

[0113] In this way, the manufacturing process of a large quantity of cases (121) can be simplified.

[0114] Through the thermal spray coating method, the porous coating layer (123) can have a microporous structure, and the contact area of the sacrificial metal in contact with moisture and air can be increased.

[0115] The preferred examples of the present invention as described above have been disclosed for illustrative purposes, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be regarded as falling within the scope of the following claims.

INDUSTRIAL APPLICABILITY

[0116] According to a battery cell related to one example of the present invention, a manufacturing method thereof, and a direct water-cooling battery module comprising the same, as the sacrificial metal having a higher ionization tendency than that of the case is subjected to an ionization reaction with moisture before the case to be oxidized, it is possible to improve corrosion resistance of the case.