Battery cell and battery module including the same

Abstract

To provide a battery cell and a battery module including the same, especially, a directly water-cooled battery cell and a directly water-cooled battery module including the same.SOLUTION: A battery cell can be improved in corrosion resistance by using sacrificial metal having larger ionization tendency than the case of the battery cell, and the heat of the battery cell can be cooled using general cooling water for vehicle.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a battery cell and a battery module including the same, and particularly to a direct water-cooled battery cell and a direct water-cooled battery module including the same. More specifically, the present invention relates to a direct water-cooled battery cell and a direct water-cooled battery module including the same that can improve the corrosion resistance of the battery cell by using a sacrificial metal that has a higher metal ionization tendency than a battery cell case.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0017379, filed on February 10, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference. [Background technology]

[0003] Batteries used in eco-cars are required to have high output, which means they generate a large amount of heat. In order to improve the performance and lifespan of the battery, it is extremely important to efficiently dissipate the heat generated by the battery and prevent the battery from overheating.

[0004] Conventionally, cooling systems for dissipating heat from a battery include direct air cooling, indirect water cooling, and direct water cooling.

[0005] The direct water cooling method involves immersing the battery cells directly in the coolant, allowing the heat from the battery cells to be directly dissipated into the coolant.

[0006] FIG. 1 is a schematic diagram of a conventional battery module 10. As shown in FIG.

[0007] 1, a direct water-cooled battery module 10 includes a cell frame 11 and a plurality of battery cells 12. The plurality of battery cells 12 are spaced apart from each other in the cell frame 11. The cell frame 11 is provided to allow cooling water to flow through it.

[0008] Generally, the battery cell 12 has an outer case that houses the internal electrodes and is made of nickel-plated iron. Therefore, if the battery cell 12 is directly immersed in coolant, the outer case is vulnerable to corrosion due to the characteristics of the material. In addition, the outer case is polarized, which causes problems with poor electrical insulation.

[0009] In a conventional direct water-cooled battery module 10, insulating oil or special cooling water M (for example, NOVEC (registered trademark) from 3M) is used to prevent corrosion of the battery cells 12.

[0010] However, insulating oil has the problem of being vulnerable to fire, and special coolants such as 3M's NOVEC (registered trademark) are excellent as coolants for battery cells because they are non-polar and corrosion-resistant, but they are expensive, which increases the unit manufacturing cost of battery modules.

[0011] In addition, when applying an anti-rust liquid to the outer case of the battery cell to prevent corrosion of the battery cell as in the conventional method, a post-processing step is required in which the outer case of the battery cell is wrapped with a non-woven fabric or the like to maintain the anti-rust liquid.

[0012] Furthermore, even if an anti-rust liquid is applied to the exterior case of the battery cell, the anti-rust agent runs off the exterior case of the battery cell due to surface tension, which causes the anti-rust agent to be unevenly applied to the exterior case. Summary of the Invention [Problem to be solved by the invention]

[0013] An object of the present invention is to provide a direct water-cooled battery cell and a direct water-cooled battery module including the same, which can improve the corrosion resistance of the battery cell by using a sacrificial metal that has a higher metal ionization tendency than the battery cell case. [Means for solving the problem]

[0014] A direct water-cooled battery cell according to one embodiment of the present invention includes an electrode assembly, a case that houses the electrode assembly, a sacrificial metal portion that is provided on the outer surface of the case and is made of a material that has a higher metal ionization tendency than the case, and a cell sheet that includes a metal layer and is provided to surround the sacrificial metal portion and the case.

[0015] The sacrificial metal portion may include one or more selected from the group consisting of aluminum, magnesium, zinc, an aluminum alloy, a magnesium alloy, and a zinc alloy.

[0016] The sacrificial metal portions may be provided on the upper and lower surfaces of the case, respectively, so that at least a partial area of ​​the upper and lower surfaces is exposed to the outside.

[0017] The sacrificial metal portion may be provided so as to have a ring shape along the circumferential direction of the upper and lower surfaces.

[0018] The sacrificial metal portion may be provided so as to have a C-shape along the circumferential direction of the upper and lower surfaces.

[0019] The cell sheet may also include an adhesive layer provided on one surface of the metal layer and attached to the case, and a waterproof layer provided on the other surface opposite to the one surface of the metal layer.

[0020] The metal layer may be made of a material having a higher metal ionization tendency than the case.

[0021] The metal layer may be formed of the same material as the sacrificial metal portion.

[0022] The cell sheet may also surround the outer surface of the case such that one end of the cell sheet overlaps the other end of the cell sheet along the circumferential direction of the case.

[0023] The sacrificial metal portion may also be laser bonded to the outer surface of the case.

[0024] The sacrificial metal portion may be provided in a strip shape so as to surround a partial region of the case.

[0025] The sacrificial metal portion may also be bonded along the periphery of the case at a central portion between the top and bottom surfaces of the case.

[0026] Furthermore, a direct water-cooled battery module according to yet another aspect of the present invention includes a plurality of direct water-cooled battery cells, a cell frame in which the plurality of battery cells are arranged at a distance from each other and in which coolant can flow between the plurality of battery cells, and a coolant supply unit for supplying coolant into the cell frame.

[0027] The battery module may further include a waterproof layer disposed inside the cell frame and covering an upper end and a lower end of the case, and the waterproof layer may include a waterproof adhesive or a potting resin.

[0028] The cooling water supply unit may be configured to supply cooling water that is not insulated. [Effects of the Invention]

[0029] As described above, the direct water-cooling battery cell and the direct water-cooling battery module including the same according to at least one aspect of the present invention have the following effects.

[0030] The corrosion resistance of the battery cells can be improved by using a sacrificial metal that has a higher ionization tendency than the battery case, and the heat of the battery cells can be cooled using low-cost general vehicle coolant that is not insulated.

[0031] In addition, the corrosion resistance of the battery cell can be improved through the metal layer provided on the case, and the heat resistance, waterproofness and insulating properties of the battery cell can be improved through the waterproof layer.

[0032] In addition, since the corrosion-resistant material (e.g., rust inhibitor) is contained in the pressure-reducing adhesive, and the metal layer is attached to the case by the pressure-reducing adhesive, the corrosion-resistant material can be uniformly applied to the outer surface of the case.

[0033] In addition, by sealing the overlapping interface of the metal layers, it is possible to prevent moisture and oxygen from penetrating into the case through the overlapping interface of the metal layers when the battery cell is immersed in cooling water at high temperatures for a long period of time. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a schematic configuration diagram of a conventional battery module. [Figure 2] 1 is a configuration diagram of a direct water-cooling battery module according to a first embodiment of the present invention; [Figure 3] 1 is a schematic perspective view of a battery cell according to a first embodiment of the present invention; [Figure 4] 4 is a schematic diagram of a cross section taken along line AA in FIG. 3. [Figure 5] 3A and 3B are diagrams illustrating the state and shape of a sacrificial metal portion according to the first embodiment of the present invention when provided on a case. [Figure 6] 3A and 3B are diagrams illustrating the state and shape of a sacrificial metal portion according to the first embodiment of the present invention when provided on a case. [Figure 7] FIG. 6 is a configuration diagram of a direct water-cooling battery module according to a second embodiment of the present invention. [Figure 8] 10A and 10B are diagrams illustrating the state and shape of a sacrificial metal portion according to a second embodiment of the present invention when provided on a case. [Figure 9] 2A and 2B are schematic perspective views of a battery cell according to a second embodiment of the present invention; [Figure 10] 10 is a schematic diagram of a cross section taken along the line BB in FIG. 9; [Figure 11] 10 is a schematic diagram of a cross section taken along the line BB in FIG. 9; DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, a direct water-cooling battery cell and a direct water-cooling battery module including the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0036] Regardless of the drawing symbols, identical or corresponding components will be given the same or similar reference numbers, and duplicate descriptions thereof will be omitted. The size and shape of each component shown for convenience of explanation may be exaggerated or reduced.

[0037] FIG. 2 is a configuration diagram of a direct water-cooling battery module according to a first embodiment of the present invention, and FIG. 3 is a schematic perspective view of a battery cell according to the first embodiment of the present invention.

[0038] FIG. 4 is a schematic view of the AA cross section of FIG. 3, and FIGS. 5 and 6 are diagrams for explaining the state and shape of the sacrificial metal part according to the first embodiment of the present invention when provided on the case.

[0039] A direct water-cooled battery cell 120 according to one embodiment of the present invention includes an electrode assembly 129, a case 121 that houses the electrode assembly 129, and sacrificial metal parts 122 and 123 that are provided on the outer surface of the case 121 and are made of a material that has a higher metal ionization tendency than the case 121. The battery cell 120 also includes a cell sheet 124 that includes a metal layer 124b and is provided to surround the sacrificial metal parts 122 and 123 and the case 121. At this time, the cell sheet 124 contacts the sacrificial metal parts 122 and 123 over at least a portion of its area.

[0040] The electrode assembly 129 is housed within the case 121 and includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. The electrodes and separator may form an integrated electrode assembly. For example, the electrode assembly 129 may be a jelly-roll type electrode assembly in which sheet-like positive and negative electrodes are wound up with a separator interposed therebetween, a stacked type electrode assembly in which a number of positive and negative electrodes are stacked in order with a separator interposed therebetween, or a stack / folded type electrode assembly in which unit cells, each of which includes a predetermined number of positive and negative electrodes stacked with a separator interposed therebetween, are placed on a separator film and wound up in order.

[0041] The case 121 accommodates the electrode assembly 129 and protects the battery cell 120 from external impact. The case 121 may be cylindrical, pouch-shaped, or rectangular, for example, cylindrical. In particular, the electrode assembly may be a wound jelly-roll type electrode assembly, the case may be a cylindrical case, and the direct water-cooling battery cell 120 may be a cylindrical battery cell.

[0042] As shown in FIG. 2, the direct water-cooling battery module 100 according to this embodiment includes a plurality of direct water-cooling battery cells 120, a cell frame 110 in which the plurality of battery cells 120 are spaced apart and in which coolant W can flow between the plurality of battery cells 120, and a coolant supply unit 150 for supplying coolant into the cell frame 110.

[0043] The cell frame 110 has a predetermined space 111 therein and is configured to allow coolant to flow within the space. The coolant W may be supplied to the internal space 111 of the cell frame 110 and then discharged to the outside of the cell frame 110. To this end, the battery module 100 may include a coolant discharge unit for discharging the coolant W to the outside of the cell frame 110. The coolant supply unit 150 may include a coolant storage tank and a pump. The coolant supply unit 150 may also be configured to supply uninsulated coolant W. The general coolant W may be coolant commonly used in vehicles.

[0044] The direct water-cooling battery cell 120 includes a case 121, sacrificial metal portions 122 and 123, and a cell sheet 124. The cell sheet 124 includes an adhesive layer 124a, a metal layer 124b, and a waterproof layer 124c.

[0045] In addition, the case 121 may be made of a metal material, and the surface of the case may be nickel-plated. That is, the surface of the case 121 may be provided with a nickel-plated layer.

[0046] In addition, the sacrificial metal portions 122 and 123 may be formed of a material having a greater metal ionization reaction than the case 121. The sacrificial metal portions 122 and 123 may include one or more selected from the group consisting of aluminum, magnesium, zinc, an aluminum alloy, a magnesium alloy, and a zinc alloy.

[0047] 4, the sacrificial metal portions 122 and 123 may be provided on the outer surface of the case 121. The sacrificial metal portions 122 and 123 may be provided on the upper surface 121a and the lower surface 121b of the case 121, respectively. The sacrificial metal portions 122 and 123 may be provided so as to expose at least a partial area of ​​the upper surface and the lower surface of the case 121 to the outside. The areas of the upper surface and the lower surface of the case 121 that are exposed to the outside may be connected to bus bars.

[0048] Referring to FIG. 5, the sacrificial metal portions 122, 123 may be provided so as to have a C-shape (or a horseshoe shape) along the circumferential direction of the upper and lower surfaces of the case 121.

[0049] Referring to FIG. 6, as another example, the sacrificial metal portions 122a and 123a may be provided to have a ring shape along the circumferential direction of the upper and lower surfaces of the case 121.

[0050] Referring to FIG. 2, when the direct water-cooled battery cell 120 is immersed in the cooling water W, the water H in the cooling water W undergoes an ionization reaction with the sacrificial metal parts 122 and 123 due to the difference in metal ionization reaction between the case 121 and the sacrificial metal parts 122 and 123 of the direct water-cooled battery cell 120. As a result, the metal ionization reaction of the case 121 is suppressed, and corrosion of the case 121 can be prevented.

[0051] 3 and 4, the cell sheet 124 is attached to surround the outer surface of the case 121. For example, the cell sheet 124 is attached to the side surface connecting the upper surface 121a and the lower surface 121b of the case 121.

[0052] The cell sheet 124 may include an adhesive layer 124a provided on one surface of the metal layer 124b and attached to the case, and a waterproof layer 124c provided on the other surface opposite to the one surface of the metal layer 124b.

[0053] Referring to FIG. 4, the cell sheet 124 is formed by integrally forming an adhesive layer 124a, a metal layer 124b, and a waterproof layer 124c.

[0054] Furthermore, cell sheet 124 surrounds the outer surface of case 121 such that one end of cell sheet 124 covers and overlaps the other end of cell sheet 124 along the circumferential direction of the side surface of case 121 .

[0055] The metal layer 124b may have a thickness of 20 μm or more to prevent oxygen and moisture penetration.

[0056] The metal layer 124b may be formed of a material having a greater metal ionization reaction than the case 121. For example, the metal layer 124b may be formed of an aluminum material. The metal layer 124b may also be formed of the same material as the sacrificial metal portions 122 and 123.

[0057] When the direct water-cooling battery cell 120 is immersed in cooling water W, the water H that has penetrated the metal layer 124b can be transferred to the sacrificial metal parts 122, 123 via the metal layer 124b. This is because the ionization reaction of the metal in the sacrificial metal parts 122, 123 with water is greater than the ionization reaction of the metal in the case 121 with water. This improves the corrosion resistance of the case 121.

[0058] The adhesive layer 124a is provided on one surface of the metal layer 124b and is a portion that adheres to the case 121. The adhesive layer 124a is provided by applying a pressure-sensitive adhesive (PSA) to one surface of the metal layer 124b.

[0059] The pressure-reducing adhesive may contain an anti-corrosion substance, which may be a rust inhibitor including substances such as phosphates, silicates, organic acid salts, or rubber grease.

[0060] Generally, if only a rust inhibitor is applied to the case 121, the surface tension causes the rust inhibitor to flow off the case 121. In contrast, in the present invention, the adhesive layer 124a adheres the cell sheet 124 to the case 121, thereby preventing the corrosion-resistant substance (e.g., the rust inhibitor) from flowing off the case 121.

[0061] A corrosion-resistant substance (e.g., a rust inhibitor) is contained in the adhesive layer 124a, and the cell sheet 124 is attached to the case 121 by a vacuum adhesive, which can have the effect of uniformly applying the corrosion-resistant substance to the outer surface of the case 121.

[0062] Waterproof layer 124c is a waterproof sheet provided on the other side of metal layer 124b to waterproof metal layer 124b. Waterproof layer 124c is a heat-resistant, insulating, and moisture-proof sheet, and a CPP (Casting Polypropylene) sheet can be used for waterproof layer 124c.

[0063] One end of the cell sheet 124 overlaps the other end of the cell sheet 124, forming a step in the overlapping area. The step interface of the cell sheet 124 is sealed with a sealing material. The sealing material may be a material containing a resin, a plasticizer, an antioxidant, and a wax.

[0064] In addition, the cell sheet 124 may be tightly bonded to the metal layer 124b by thermocompression bonding at the overlapping interface where one end of the waterproof layer 124c covers the other end of the waterproof layer 124c.

[0065] As a result, an embodiment of the present invention can prevent moisture and oxygen from penetrating into the case 121 through the overlapped interface of the cell sheet 124 when the battery cell is immersed in cooling water at high temperatures for a long period of time.

[0066] Meanwhile, the battery module 100 may include waterproof layers 125 and 126 provided inside the cell frame 110 and covering the upper surface 121a side end and the lower surface 121b side end of the case 121, respectively. The waterproof layers 125 and 126 prevent moisture from penetrating into the case 121. An upper waterproof layer 125 may be provided at the upper end of the case 121, and a lower waterproof layer 126 may be provided at the lower end of the case 121. Referring to FIGS. 3 and 4 , the waterproof layers 125 and 126 may be provided to surround the sacrificial metal portions 122 and 123. That is, the waterproof layers 125 and 126 prevent the sacrificial metal portions 122 and 123 from coming into contact with the coolant W inside the cell frame 110. Furthermore, the upper surface 121a and the lower surface 121b of the battery cell 120 can be fixed to the inner surface of the cell frame 110 via waterproof layers 125 and 126, respectively.

[0067] The waterproof layers 125 and 126 may include 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.

[0068] FIG. 7 is a structural diagram of a direct water-cooled battery module according to a second embodiment of the present invention, FIG. 8 is a diagram for explaining the state and shape of a sacrificial metal part according to the second embodiment of the present invention when provided on a case, FIG. 9 is a schematic perspective view of a battery cell according to the second embodiment of the present invention, and FIGS. 10 and 11 are schematic views of the BB cross section of FIG. 9.

[0069] Referring to FIG. 7, the direct water-cooled battery module 200 according to this embodiment includes a plurality of direct water-cooled battery cells 220, a cell frame 210 in which the plurality of battery cells 220 are spaced apart and in which coolant W can flow between the plurality of battery cells 220, and a coolant supply unit 250 for supplying the coolant W to an internal space 211 of the cell frame 210.

[0070] In the direct water-cooling battery module 200 according to this embodiment, the cell frame 210 and the coolant supply unit 250 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0071] The direct water-cooling battery cell 220 according to this embodiment includes an electrode assembly 229, a case 221 that houses the electrode assembly 229, a sacrificial metal portion 222 provided on the outer surface of the case 221, a corrosion-resistant sheet 223, and a waterproof sheet 224. The battery module 200 also includes an upper waterproof layer 225 and a lower waterproof layer 226.

[0072] The case 221, the upper waterproof layer 225, and the lower waterproof layer 226 are the same as those in the first embodiment, and therefore, a description thereof will be omitted in this embodiment.

[0073] The direct water-cooling battery cell 220 according to this embodiment differs from the first embodiment in the installation position of the sacrificial metal portion 222, and the following description will focus on the sacrificial metal portion 222.

[0074] The sacrificial metal portion 222 may be made of a material that has a greater metal ionization reaction than the case 221 .

[0075] 8, the sacrificial metal portion 222 may be provided in a band shape to surround a portion of the case 221. The sacrificial metal portion 222 may be bonded along the periphery of the case 221 at a central portion between an upper surface 221a and a lower surface 221b of the case 221. The sacrificial metal portion 222 is bonded to the case 221 by laser welding.

[0076] 9 and 10, the waterproof sheet 224 surrounds the sacrificial metal portion 222. The waterproof sheet 224 is thermally shrunk and tightly bonded to the outer surface of the case 221, thereby preventing moisture from penetrating into the case.

[0077] The waterproof sheet 224 may be made of a heat-shrinkable polymer material, which may include one or more selected from the group consisting of polyvinyl chloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET).

[0078] Referring to FIG. 11, in order to improve the corrosion resistance of the direct water-cooled battery module 200, before bonding the waterproof sheet 224 to the case 221, the case 221 may be subjected to a corrosion-resistant treatment using a corrosion-resistant sheet 223, and then the waterproof sheet 224 may be bonded.

[0079] Here, the corrosion-resistant sheet 223 surrounds the outer surface of the case 221 including the sacrificial metal portion 222. Thereafter, the waterproof sheet 224 surrounds the corrosion-resistant sheet 223 and is bonded to the outer surface of the case 221 in close contact with it while being thermally shrunk.

[0080] The corrosion-resistant sheet 223 is made of a material that allows the corrosion-resistant substance to be uniformly absorbed. For example, the corrosion-resistant sheet 223 may be made of a material that allows the corrosion-resistant substance to be uniformly absorbed, such as a fabric such as a nonwoven fabric or cotton fabric.

[0081] The corrosion-resistant sheet 223 can be adhered to the case 221 by applying a sheet adhesive in a molten state using a hot-melting method and then cooling it. Here, an acrylic adhesive can be used as the sheet adhesive.

[0082] When the corrosion-resistant substance (e.g., rust inhibitor) is uniformly absorbed over the entire area of ​​the corrosion-resistant sheet 223 and comes into contact with the case 221, the effect of the corrosion-resistant substance being uniformly applied to the outer surface of the case 221 can be achieved.

[0083] The preferred embodiments of the present invention described above have been disclosed for illustrative purposes, and those skilled in the art having ordinary skill in the art may make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following claims. [Industrial Applicability]

[0084] According to at least one embodiment of the direct water-cooling battery cell and a direct water-cooling battery module including the same, the corrosion resistance of the battery cell can be improved by using a sacrificial metal that has a higher metal ionization tendency than the battery case. [Explanation of symbols]

[0085] 100, 200 Direct water-cooled battery module (battery module) 120, 220 Direct water cooling battery cell (battery cell) 121, 221 cases 122, 123, 222 Sacrificial metal parts 124 sell sheets 124b Metal layer 129, 229 electrode assembly 224 Tarpaulin

Claims

1. an electrode assembly; a case that accommodates the electrode assembly; a sacrificial metal portion provided on the outer surface of the case and made of a material having a higher metal ionization tendency than the case; a cell sheet including a metal layer and provided so as to surround the sacrificial metal portion and the case; Including battery cells.

2. The battery cell of claim 1 , wherein the sacrificial metal portion comprises one or more selected from the group consisting of aluminum, magnesium, zinc, an aluminum alloy, a magnesium alloy, and a zinc alloy.

3. The battery cell according to claim 1 , wherein the sacrificial metal portions are provided on the upper and lower surfaces of the case, respectively, so as to expose at least partial areas of the upper and lower surfaces of the case to the outside.

4. The battery cell according to claim 3 , wherein the sacrificial metal portion is provided in a ring shape along the periphery of the upper and lower surfaces of the case.

5. The battery cell according to claim 3 , wherein the sacrificial metal portion is provided in a C-shape along the periphery of the upper and lower surfaces of the case.

6. The cell sheet is an adhesive layer provided on one surface of the metal layer and adhering to the case; a waterproof layer provided on the other surface opposite to the one surface of the metal layer; The battery cell of claim 1 , comprising:

7. The battery cell according to claim 1 , wherein the metal layer is formed of a material having a higher metal ionization tendency than the case.

8. The battery cell according to claim 7 , wherein the metal layer is formed of the same material as the sacrificial metal portion.

9. The battery cell according to claim 1 , wherein the cell sheet surrounds the outer surface of the case such that one end of the cell sheet covers and overlaps the other end of the cell sheet along a circumferential direction of the case.

10. The battery cell of claim 1 , wherein the sacrificial metal portion is laser bonded to the outer surface of the case.

11. The battery cell according to claim 1 , wherein the sacrificial metal portion surrounds a portion of the case in a strip shape.

12. The battery cell of claim 11 , wherein the sacrificial metal portion is bonded along the periphery of the case in a central portion between the upper and lower surfaces of the case.

13. a plurality of the battery cells of claim 1; a cell frame in which a plurality of battery cells are arranged at a distance from each other and in which a coolant can flow between the plurality of battery cells; a cooling water supply unit for supplying cooling water to the inside of the cell frame; Including the battery module.

14. a waterproof layer provided inside the cell frame and covering an upper end and a lower end of the case, The battery module according to claim 13 , wherein the waterproof layer comprises a waterproof adhesive or a potting resin.

15. The battery module according to claim 14 , wherein the cooling water supply unit is configured to supply non-insulated cooling water.

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