Battery cell and battery module including the same

Abstract

The present invention relates to a battery cell and a battery module including the same, and more particularly to a battery cell for direct water cooling and a battery module for direct water cooling including the same. According to the present invention, the corrosion resistance of the battery cell can be improved by using a sacrificial metal having a higher metal ionization tendency than a battery cell case, and the heat of the battery cell can be cooled by using general vehicle coolant.

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. 10-2022-00410076, filed April 1, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Batteries used in eco-cars are required to have high output, which generates 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 12 to prevent corrosion of the battery cell 12 as in the conventional method, a post-treatment process 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 12, 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 first plating layer formed on the outer surface of the case, a scratch portion formed by removing a portion of the first plating layer, and a sacrificial metal portion that surrounds the scratch portion and is formed of a material that has a higher metal ionization tendency than the first plating layer.

[0015] The scratched portion may be formed by removing a portion of the first plating layer along a thickness direction of the first plating layer.

[0016] The scratched portion may be formed along the thickness direction of the first plating layer, from a portion of the first plating layer to an outer peripheral surface of the case facing the portion. In this case, the sacrificial metal portion may be bonded to the outer peripheral surface of the case by a laser brazing method. Specifically, the sacrificial metal portion may be bonded to the outer peripheral surface of the case by melting a region of the sacrificial metal portion that passes through the portion of the first plating layer with a laser beam.

[0017] 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.

[0018] The scratch portion may be provided in a band shape along the periphery of the case.

[0019] The scratch portion may include a first scratch portion located at an upper end of the case and a second scratch portion located at a lower end of the case. The sacrificial metal portion may surround the first scratch portion and the second scratch portion so that the first and second scratch portions are not exposed to the outside. The sacrificial metal portion may be bonded to the first scratch portion and the second scratch portion, respectively. The sacrificial metal portion may be bonded to the first scratch portion and the second scratch portion while being melted by a laser beam.

[0020] The first plating layer may also include a nickel plating layer.

[0021] The scratched portion may be formed by peeling off a partial area of ​​the first plating layer with a laser or by peeling off a partial area of ​​the first plating layer through etching.

[0022] The battery cell may include a cell sheet including a polymer film and surrounding the sacrificial metal portion.

[0023] The cell sheet may 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.

[0024] In addition, a battery module according to one aspect of the present invention includes the plurality of battery cells, a cell frame in which the 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, and a coolant supply unit for supplying coolant into the inside of the cell frame.

[0025] The battery module may further include a waterproof layer disposed inside the cell frame and covering the upper and lower ends of the case, and the waterproof layer may include a waterproof adhesive or a potting resin.

[0026] The cooling water supply unit may be configured to supply cooling water that is not insulated. [Effects of the Invention]

[0027] 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.

[0028] The corrosion resistance of the battery cell can be improved by using a sacrificial metal that has a higher ionization tendency than the battery cell case and the first plating layer.In addition, the heat of the battery cell can be cooled using general coolant for low-cost vehicles that are not insulated.

[0029] In addition, the heat resistance, waterproofing, and insulating properties of the battery cell can be improved through the cell sheet surrounding the sacrificial metal portion. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic configuration diagram of a conventional battery module. [Figure 2] 1 is a schematic diagram showing a direct water-cooling battery module according to an embodiment of the present invention; FIG. [Figure 3] FIG. 2 is a front view showing a scratched portion of a battery cell according to an embodiment of the present invention. [Figure 4] FIG. 2 is a front view showing a scratched portion of a battery cell according to an embodiment of the present invention. [Figure 5] 10A and 10B are diagrams for explaining a method of joining a scratch portion and a sacrificial metal portion. [Figure 6] FIG. 10 is a perspective view schematically illustrating a battery cell in a state where a sacrificial metal portion is bonded onto a first plating layer. [Figure 7] FIG. 2 is a perspective view schematically illustrating a battery cell arranged in a battery module. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a state cut along line XX in FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view schematically showing a state cut along line XX in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, a direct water-cooling battery cell (hereinafter also referred to as a "battery cell") according to one embodiment of the present invention and a direct water-cooling battery module (hereinafter also referred to as a "battery module") including the same will be described in detail with reference to the drawings.

[0032] 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.

[0033] FIG. 2 is a schematic diagram showing a direct water-cooling battery module 100 according to one embodiment of the present invention, and FIGS. 3 and 4 are front views showing a scratched portion of a battery cell 120 according to one embodiment of the present invention.

[0034] 2, a battery module 100 according to an embodiment of the present invention includes a plurality of battery cells 120, a cell frame 110 that houses the plurality of battery cells 120, and a coolant supply unit 150. The battery module 100 also includes the cell frame 110 in which the plurality of battery cells 120 are spaced apart from each other and in which coolant W can flow between the plurality of battery cells 120, and the coolant supply unit 150 that supplies coolant into the cell frame 110.

[0035] Furthermore, the cell frame 110 has a predetermined space 111 therein, and is configured to allow the coolant W to flow within the space 111. 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. For this purpose, 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. Furthermore, the coolant supply unit 150 may be configured to supply uninsulated coolant W. The general coolant W may be coolant commonly used in vehicles.

[0036] FIG. 5 is a diagram for explaining a method of bonding a scratch portion and a sacrificial metal portion, FIG. 6 is a perspective view schematically showing a battery cell with a sacrificial metal portion bonded to a first plating layer, FIG. 7 is a perspective view schematically showing a battery cell arranged in a battery module, and FIGS. 8 and 9 are cross-sectional views schematically showing a state cut along line XX in FIG. 7.

[0037] A battery cell 120 according to an embodiment of the present invention includes an electrode assembly 121, a case 122, a first plating layer 123, a scratch portion 124, and a sacrificial metal portion 125. The battery cell 120 may also include a cell sheet 126 including a polymer film and disposed to surround the sacrificial metal portion 125.

[0038] The battery cell 120 includes an electrode assembly 121, a case 122 that houses the electrode assembly 121, a first plating layer 123 formed on the outer peripheral surface of the case 122, a scratch portion 124 (124a, 124b) formed by removing a portion of the first plating layer 123, and a sacrificial metal portion 125 that is arranged to surround the scratch portion 124 and is formed of a material having a higher metal ionization tendency than the first plating layer 123.

[0039] 2, when the direct water-cooling battery cell 120 is immersed in cooling water W, the water H may be transferred to the sacrificial metal part 125. At this time, the metal ionization reaction of the sacrificial metal part 125 with the water H is greater than the metal ionization reaction of the case 122 with the water, thereby improving the corrosion resistance of the case 210.

[0040] As an example, the sacrificial metal portion 125 may be plated onto the first plating layer 123 or may be welded onto the first plating layer 123.

[0041] Referring to FIG. 2, when the battery module 100 uses general coolant W, if water H penetrates through the corroded portion on the surface of the battery cell 120, the power source of the battery cell may be electrically connected to the general coolant, which may cause damage to the battery module 100.

[0042] 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 part 212 due to the difference in the metal ionization reaction between the case 122 and the sacrificial metal part 125 of the direct water-cooled battery cell 120. As a result, the metal ionization reaction of the case 122 is suppressed, and corrosion of the case 122 can be prevented.

[0043] The electrode assembly 121 is housed in a case 122 and includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. The electrodes and separator may be integrated to form the electrode assembly 121. For example, the electrode assembly 121 may be a jelly-roll type electrode assembly in which sheet-shaped 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.

[0044] In addition, the case 122 accommodates the electrode assembly 121 and serves to protect the battery cell 120 from external impact. The case 122 may be cylindrical, pouch-shaped, or rectangular, for example, the case 122 may be cylindrical. In particular, the electrode assembly 121 may be a wound jelly-roll type electrode assembly, the case 122 may be a cylindrical case, and the direct water-cooling battery cell 120 may be a cylindrical battery cell.

[0045] In addition, the case 122 may be made of a metal material, and the case 122 may be made of one or more selected from the group consisting of steel and stainless steel.

[0046] The surface of the case 122 may be plated with nickel (Ni). That is, the first plating layer 123 may include a nickel plating layer.

[0047] On the other hand, nickel plating layers are less likely to discolor and have excellent rust prevention, corrosion resistance, and wear resistance. However, due to their material properties, nickel plating layers can corrode when immersed in cooling water, and as corrosion progresses, polarity develops and insulation properties deteriorate.

[0048] On the other hand, when the sacrificial metal portion 125 is provided on the first plating layer 123, the first plating layer 123 can become a factor that hinders the movement of electrons between the sacrificial metal portion 125 and the case 122.

[0049] After forming the scratched portion 124 on the first plating layer 123, the sacrificial metal portion 125 is bonded to the scratched portion 124, thereby allowing electrons to be transferred smoothly between the sacrificial metal portion 125 and the case 122.

[0050] 3 and 8, the scratched portion 124 (124a) may be formed by removing a portion of the first plating layer 123 along the thickness direction t of the first plating layer 123. That is, the scratched portion may be formed by scraping off a predetermined thickness of the first plating layer 123, and the thickness of the first plating layer in the region where the scratched portion 124 is formed on the first plating layer 123 is smaller than that of the surrounding region.

[0051] The scratched portion 124 may be formed by peeling off a portion of the first plating layer 123 with a laser or by etching the first plating layer 123. That is, the scratched portion 124 may be formed by scratching the first plating layer 123 with a laser, or by etching the first plating layer 123. The etching method is a chemical corrosion method.

[0052] 3 and 9, the scratched portion 124 (124c) may be formed in a portion of the first plating layer 123 along the thickness direction t of the first plating layer 123 and up to the outer peripheral surface of the case facing the portion. That is, the scratched portion 124c may be formed by scratching the first plating layer 123, penetrating the first plating layer 123 along the thickness direction t, and then scratching up to the exposed outer peripheral surface 122c of the case. At this time, the sacrificial metal portion 125 may be bonded to the outer peripheral surface 122c of the case 122. In this structure, the sacrificial metal portion 125 may penetrate the first plating layer 123 and be directly bonded to the outer peripheral surface 122c of the case 122.

[0053] 3 and 4, scratching the first plating layer 123 may form a plurality of recesses in the scratched area. As an example, the recesses may be arranged in a grid pattern. Furthermore, the scratched portion 124 may be arranged in a band pattern along the circumferential direction of the case 122.

[0054] Furthermore, the scratch portion 124 may be provided in a plurality of different regions of the first plating layer 123. For example, the scratch portion 124 may include a first scratch portion 124a located at the upper end 122a of the case 122 and a second scratch portion 124b located at the lower end 122b of the case 122.

[0055] 5 and 6, the sacrificial metal portion 125 may be disposed so as to surround the outer surface of the case 122 and may be disposed on the first plating layer 123 so as to surround the first plating layer 123.

[0056] In addition, the sacrificial metal portion 125 may be formed of a material having a greater metal ionization reaction than the case 122. The sacrificial metal portion 125 may include one or more selected from the group consisting of aluminum, magnesium, zinc, an aluminum alloy, a magnesium alloy, and a zinc alloy.

[0057] The sacrificial metal portion 125 is provided to surround the scratch portion 124 so that the scratch portion 124 is not exposed to the outside. As an example, the sacrificial metal portion 125 may be provided to surround the first scratch portion 124a and the second scratch portion 124b so that the first scratch portion 124a and the second scratch portion 124b are not exposed to the outside.

[0058] In this specification, the scratch portion 124 (first scratch portion 124a, second scratch portion 124b) may include an area where a portion of the thickness of the first plating layer 123 is scratched, and an area where the scratch treatment penetrates the first plating layer 123 to the outer peripheral surface of the case.

[0059] In this case, the sacrificial metal portion 125 may be bonded to the scratch portion 124, and if a plurality of scratch portions are provided, the sacrificial metal portion 125 may be bonded to the first scratch portion 124a and the second scratch portion 124b, respectively.

[0060] Furthermore, the first scratch portion 124a and the second scratch portion 124b may each be provided in a band shape along the circumferential direction of the case 122. Furthermore, the sacrificial metal portion 125 may be provided in a band shape along the circumferential direction of the case 122.

[0061] 4 and 6, the upper end of the sacrificial metal portion 125 may cover the first scratch portion 124a, and the lower end of the sacrificial metal portion 125 may cover the second scratch portion 124b. In this manner, the sacrificial metal portion 125 may be provided in the shape of a band that covers the scratch portion 124 and is coupled to the first plating layer 123 along the periphery of the case 122.

[0062] 5, the sacrificial metal portion 125 may be bonded to the scratched portion by a laser brazing method along imaginary bonding lines L1 and L2 extending in the circumferential direction of the case 121. FIG. 5 is a view illustrating a process of bonding the sacrificial metal portion to the outer peripheral surface of the case 122 (see FIG. 9) in an embodiment in which the scratched portion is formed through the first plating layer to the outer peripheral surface of the case.

[0063] Referring to FIG. 5, the sacrificial metal portion 125 can be bonded to the outer circumferential surface of the case 122 by melting the wire W with the laser beam B.

[0064] 4 to 6, the upper end of the sacrificial metal portion 125 may be bonded to the first scratch portion 124a by melting the wire W with a laser beam along the first bonding line L1. Here, the first bonding line L1 refers to an imaginary line along which the wire W is bonded to the first scratch portion 124a.

[0065] The lower end of the sacrificial metal portion 125 may be bonded to the second scratch portion 124b by melting the wire W with a laser beam along the second bonding line L2, where the second bonding line L2 refers to an imaginary line along which the wire W is bonded at the second scratch portion 124b.

[0066] That is, the sacrificial metal portion 125 may be provided to surround the upper and lower ends of the case 122, and the sacrificial metal portion 125 may be provided on the upper end 122a and the lower end 122b of the case 122, respectively.

[0067] The sacrificial metal portion 125 may be provided in a band shape to surround a portion of the circumferential direction of the case 122. The sacrificial metal portion 125 may be provided in a ring shape to surround the case 122 along the circumferential direction of the case 122.

[0068] 7 to 9, the battery cell 120 may include a cell sheet 126 including a polymer film and surrounding the sacrificial metal portion 125.

[0069] The cell sheet 126 may surround the outer surface of the case 122 such that one end of the cell sheet 126 overlaps the other end of the cell sheet 126 along the circumferential direction of the case 122 .

[0070] Furthermore, the cell sheet 126 can be closely attached to the sacrificial metal portion 125 while being thermally shrunk.

[0071] The cell sheet 126 may be formed 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).

[0072] Meanwhile, the battery module 100 may include waterproof layers 130 and 140 provided inside the cell frame 110 to cover the upper end 122a and the lower end 122b of the case 122 of the battery cell 120, respectively.

[0073] The waterproof layers 130 and 140 prevent moisture from penetrating into the case 122 and fix the battery cells 120 to the cell frame 110 .

[0074] An upper waterproof layer 130 may be provided at an upper end 122a of the case 122, and a lower waterproof layer 140 may be provided at a lower end 122b of the case 122. For example, the waterproof layers 130 and 140 may be provided to surround a portion of the sacrificial metal portion 125. In addition, the upper end 122a and the lower end 122b of the battery cell 120 may be fixed to the inner surface of the cell frame 110 via the waterproof layers 130 and 140, respectively.

[0075] The waterproof layers 130 and 140 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.

[0076] 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]

[0077] 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 having a higher metal ionization tendency than the battery cell case and the first plating layer. [Explanation of symbols]

[0078] 120 battery cells 121 Electrode assembly 122 cases 123 First plating layer 124 Scratch Section 125 Sacrificial Metal Part

Claims

1. an electrode assembly; a case that houses the electrode assembly; a first plating layer formed on the outer surface of the case; a scratched portion formed by removing a portion of the first plating layer; a sacrificial metal portion provided to surround the scratch portion and formed of a material having a higher metal ionization tendency than the first plating layer; A battery cell comprising: a battery cell including: a first end; a second end; a third end; a fourth end; a fourth end; a fifth end; a fifth end; a sixth ...

2. The battery cell according to claim 1 , wherein the scratched portion is formed by removing a portion of the first plating layer along a thickness direction of the first plating layer.

3. 3. The battery cell according to claim 2, wherein the scratch portion is formed along a thickness direction of the first plating layer, from a portion of the first plating layer to an outer peripheral surface of the case facing the portion of the first plating layer.

4. The battery cell according to claim 3 , wherein the sacrificial metal portion is bonded to an outer peripheral surface of the case.

5. 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.

6. The battery cell according to claim 1 , wherein the scratch portion is provided in a band shape along the circumferential direction of the case.

7. The scratch portion includes a first scratch portion located at an upper end of the case and a second scratch portion located at a lower end of the case, The battery cell of claim 1 , wherein the sacrificial metal portion surrounds the first scratched portion and the second scratched portion so that the first scratched portion and the second scratched portion are not exposed to the outside.

8. The battery cell of claim 7 , wherein the sacrificial metal portion is coupled to the first scratch portion and the second scratch portion, respectively.

9. The battery cell of claim 1 , wherein the first plating layer comprises a nickel plating layer.

10. 2. The battery cell of claim 1, wherein the scratched portion is formed by peeling off a portion of the first plating layer with a laser and / or by peeling off a portion of the first plating layer through an etching process.

11. The battery cell according to claim 1 , further comprising a cell sheet including a polymer film and disposed so as to surround the sacrificial metal portion.

12. The battery cell according to claim 11 , wherein the cell sheet surrounds 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.

13. A plurality of battery cells according to claim 1; a cell frame in which a plurality of battery cells are arranged at a distance from each other and in which a cooling water is allowed to 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 13 , wherein the cooling water supply unit is configured to supply non-insulated cooling water.

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