Compression pad, battery cell stack including compression pad, and battery module

Abstract

A battery cell stack according to an embodiment of the present invention may comprise: a plurality of battery cells arranged in parallel to each other, each battery cell comprising an electrode assembly having an electrode tab and an external material accommodating the electrode assembly; and a compression pad interposed between the plurality of battery cells. Each compression pad includes: a main portion; and a side portion provided at an end portion of the main portion and having a compression ratio lower than that of the main portion, the side portion overlapping with a side portion of an electrode tab of the battery cell with respect to a thickness direction of the compression pad.

Description

Technical Field

[0001] Cross-reference of related technologies

[0002] This application claims priority to Korean Patent Application No. 10-2023-0190432, filed in Korea on December 22, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0004] This disclosure relates to a compression pad placed between multiple battery cells, a battery cell stack including the compression pad, and a battery module. Background Technology

[0005] With technological advancements and the growing demand for mobile devices, the need for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting significant attention as a power source for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, as well as for powering electric bicycles, electric vehicles, and hybrid electric vehicles.

[0006] Small mobile devices use at least one battery per device, while medium and large devices, such as vehicles, require high output and large capacity. Therefore, medium and large battery modules, which include multiple battery cells that are electrically connected, are used.

[0007] The goal is to minimize the size and weight of medium and large battery modules, and therefore, to use prismatic or pouch-shaped batteries, which can be tightly stacked and have a low weight per capacity, primarily as battery cells for medium and large battery modules.

[0008] Additionally, the battery module may include a module frame that houses the battery cell stacks within an internal space to protect the battery cell stacks from external impacts, heat, or vibration.

[0009] Battery cell stacks may include multiple battery cells and compression pads that contact the battery cells. The compression pads can absorb shocks transmitted to adjacent battery cells and slow down heat propagation in the event of a fire in any battery cell.

[0010] When expansion occurs due to gas generated during the charging and discharging of the battery cell, a compression pad applies pressure to the battery cell as it is compressed. However, because the thickness of the battery cell is not uniform at each location, the pressure applied by the compression pad to the battery cell may vary, and gas may migrate to areas of lower pressure, leading to performance degradation of the battery cell, such as lithium deposition. Summary of the Invention Technical issues

[0011] This disclosure aims to provide a compression pad for applying uniform pressure to a battery cell, as well as a battery cell stack and a battery module including the compression pad. Technical solution

[0012] A battery cell stack according to embodiments of the present disclosure may include: a plurality of battery cells arranged parallel to each other, each battery cell including an electrode assembly and an outer packaging, the electrode assembly having electrode tabs, the outer packaging accommodating the electrode assembly; and a compression pad disposed between the plurality of battery cells. The compression pad may include: a main portion; and a side portion disposed at an end portion of the main portion and having a lower compression ratio than the main portion, the side portion overlapping a portion of the electrode tab side region of the battery cell in the thickness direction of the compression pad.

[0013] The electrode assembly may include electrodes and spacers arranged in an alternating manner. The electrodes may include overlapping regions where electrode tabs are connected, and the overlapping regions overlap with the side portions along the thickness direction of the compression pad.

[0014] The length of the overlapping region in the longitudinal direction of the battery cell can be 5% to 10% of the length of the electrode.

[0015] The side portion may include: an inner portion connected to the main portion and having a thickness corresponding to the main portion; and an outer portion located outside the inner portion and having an outwardly increasing thickness.

[0016] When the compression pad is separated from multiple battery cells, the thickness of the inner part and the thickness of the outer part can correspond to each other.

[0017] The main portion may include polyurethane material, and the side portions may include silicone material.

[0018] The side portions can be positioned on both sides along the length of the battery cell, with the main portion placed between the two sides.

[0019] The main part can correspond to the central part and the long edge part of the battery cell, and the side part can correspond to the short edge part of the battery cell.

[0020] A battery module according to embodiments of the present disclosure may include: a module housing; and a battery cell stack housed within the module housing. The battery cell stack may include: a plurality of battery cells arranged parallel to each other, each battery cell including an electrode assembly and an outer packaging, the electrode assembly having electrode tabs, the outer packaging housing the electrode assembly; and a compression pad disposed between the plurality of battery cells. The compression pad may include: a main portion; and a side portion disposed at an end portion of the main portion and having a lower compression ratio than the main portion, the side portion overlapping a portion of the electrode tab side region of the battery cell in the thickness direction of the compression pad.

[0021] The battery module may also include a busbar frame disposed outside the battery cell stack, on which busbars are mounted. The battery cell may also include electrode leads connected to electrode tabs, protruding outward from the outer packaging and connecting to the busbars. Side portions may face the busbar frame with respect to the length of the battery cell.

[0022] A compression pad according to an embodiment of the present disclosure can be placed between multiple battery cells arranged parallel to each other. Each battery cell includes an electrode assembly and an outer packaging. The electrode assembly has electrode tabs, and the outer packaging houses the electrode assembly. The compression pad may include: a main portion; and a side portion disposed at an end portion of the main portion and having a lower compression ratio than the main portion. The side portion overlaps with a portion of the electrode tab side region of the battery cell in the thickness direction of the compression pad. Beneficial effects

[0023] According to an exemplary embodiment of this disclosure, in the event of expansion within the battery cell, the side portion of the compression pad may have a lower compression ratio than the main portion in order to compensate for the thickness difference between the electrode tab side region and the central region of the battery cell. Therefore, the compression pad can apply uniform pressure to the battery cell, thereby preventing performance degradation of the battery cell caused by lithium deposition.

[0024] Furthermore, the effects of this disclosure may include those readily predictable by those skilled in the art from the exemplary embodiments of this disclosure. Attached Figure Description

[0025] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description, are intended to provide a better understanding of the technical aspects of the present disclosure, and therefore the present disclosure should not be construed as limited to the drawings.

[0026] Figure 1 This is a perspective view of a battery module according to an embodiment of the present disclosure.

[0027] Figure 2 yes Figure 1 The image shows an exploded perspective view of the battery module.

[0028] Figure 3 This is a plan view of a battery cell stack according to an embodiment of the present disclosure.

[0029] Figure 4 This is a diagram illustrating the operation of a compression pad according to an embodiment of the present disclosure.

[0030] Figure 5 This is a cross-sectional view showing the compression pad and the internal portion of the battery cell according to an embodiment of the present disclosure.

[0031] Figure 6 This is a schematic diagram showing a compression pad and battery cell according to another embodiment of the present disclosure. Detailed Implementation

[0032] In the following, exemplary embodiments of the present disclosure will be described in sufficient detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the disclosure. However, the present disclosure may be implemented in many different forms and is not limited to or construed as described below.

[0033] In order to clearly describe this disclosure, irrelevant descriptions or detailed descriptions of related known techniques that may unnecessarily obscure the gist of this disclosure have been omitted, and throughout the specification, the same or similar reference numerals are attached to the same or similar elements when reference numerals are attached to the elements in the figures.

[0034] Furthermore, the terms or words used in the specification and appended claims should not be construed as limited to their general or dictionary meanings, but should be interpreted based on their meanings and concepts corresponding to the technical aspects of this disclosure, on the basis of allowing the inventors to appropriately define the terms for the best interpretation.

[0035] In the accompanying drawings, each element of a secondary battery according to an embodiment of the present disclosure is schematically shown, and the dimensions of the elements or the thickness of the lines may be slightly exaggerated for ease of understanding.

[0036] Figure 1 This is a perspective view of a battery module according to an embodiment of the present disclosure, and Figure 2 yes Figure 1 The image shows an exploded perspective view of the battery module.

[0037] According to embodiments of the present disclosure, the battery module 10 may include a battery cell stack 100 and a module housing 20.

[0038] The battery cell stack 100 can be housed within the module housing 20. The battery cell stack 100 may include a plurality of battery cells 200 and a compression pad 300 disposed between the plurality of battery cells 200.

[0039] Multiple battery cells 200 can be arranged parallel to each other. Multiple battery cells 200 can be arranged facing each other along a first direction (e.g., a direction parallel to the Y-axis). More specifically, multiple battery cells 200 can be stacked on top of each other along the first direction. Additionally, each battery cell 200 can extend along a second direction perpendicular to the first direction (e.g., a direction parallel to the X-axis). The first direction can be parallel to the width direction of the module frame 20, the thickness direction of the battery cell 200, or the thickness direction of the compression pad 300. The second direction can be parallel to the length direction of the module frame 20, the length direction of the battery cell 200, or the length direction of the compression pad 300.

[0040] The length direction of each battery cell 200 may be parallel to the second direction. The width direction of each battery cell 200 may be parallel to a third direction (e.g., a direction parallel to the Z-axis), which is perpendicular to the first and second directions.

[0041] Each battery cell 200 may include: an electrode assembly 210 having electrode tabs 213; and an outer packaging 220 that houses the electrode assembly 210 (see...). Figure 5 ).

[0042] Electrode assembly 210 can be formed by placing electrodes 211 and spacers 212 in an alternating manner. That is, electrode assembly 210 may include a plurality of electrodes 211 and spacers 212 disposed between the plurality of electrodes 211 to insulate the plurality of electrodes 211 from each other. Electrode assembly 210 may be of various types, such as stacked, wound, or stack-folded, and the type of electrode assembly 210 is not limited to these.

[0043] Each battery cell 200 can be a pouch-type battery cell. Pouch-type battery cells allow for a maximum number of cells stacked per unit area, resulting in increased energy density of the battery module 10. For example, the battery cell 200 can be manufactured by receiving the electrode assembly 210 in an outer package 220 of a shaped laminate and sealing the outer package 220 by thermal fusion. However, the battery cell 200 is not limited to a pouch type and can be prismatic, cylindrical, or any other type where such other types are sufficient to achieve the storage capacity required by the device on which the battery cell 200 will subsequently be mounted.

[0044] Each battery cell 200 may have an electrode tab 213. The electrode tab 213 can connect the electrode 211 of the electrode assembly 210 to the electrode lead 214, as described below. The electrode tab 213 may include a positive electrode tab connected to the positive electrode and a negative electrode tab connected to the negative electrode.

[0045] Each battery cell 200 may have electrode leads 214. The electrode leads 214 may include a positive electrode lead connected to a positive electrode contact and a negative electrode lead connected to a negative electrode contact. That is, the electrode leads 214 may include a pair of electrode leads projecting in opposite directions and may project parallel to the length direction of the battery cell 200. However, this disclosure is not limited thereto, and the pair of electrode leads 214 may project parallel to each other in the same direction.

[0046] Compression pad 300 can be placed between multiple battery cells 200. Compression pad 300 may include at least one compression pad, and preferably multiple compression pads. For example, such as... Figure 3 As shown, multiple battery cells 200 and multiple compression pads 300 can be arranged in an alternating manner.

[0047] The battery cell 200 can contact two surfaces of each compression pad 300. More specifically, the two surfaces of each compression pad 300 can contact adjacent battery cells 200.

[0048] In the event of expansion within the battery cell 200, the compression pad 300 can be compressed between the two battery cells 200. The compression pad 300 can apply pressure to the battery cell 200 to suppress expansion within the battery cell 200 and mitigate the impact applied to the battery cell 200.

[0049] Compression pads 300 can be arranged parallel to battery cells 200. More specifically, the length direction of each compression pad 300 can be parallel to a second direction. The width direction of each compression pad 200 can be parallel to a third direction.

[0050] The detailed configuration of the compression pad 300 will be described in detail below.

[0051] Meanwhile, the module frame 20 can form the exterior of the battery module 10. The module frame 20 may include a high-strength metal material.

[0052] The structure of the module frame 20 can vary. As an example, the module frame 20 can be a single frame. The single frame can be a metal plate with an integrally formed top surface, bottom surface, and two side surfaces. As another example, the module frame 20 can have a structure where a U-shaped frame and a top plate (top surface) are combined. The U-shaped frame can be a metal plate with a combined or integrally formed bottom plate (bottom surface) and side plates (two sides). Furthermore, the structure of the module frame 20 can be provided as a structure where L-shaped frames are combined, and can be provided as various structures not described in the examples above.

[0053] The module frame 20 may have an internal space that can accommodate the battery cell stack 100. More specifically, the module frame 20 may include a top surface, a bottom surface, and two sides. The module frame 20 may have two open end portions in the longitudinal direction, and these two open end portions may be covered by end caps 40, as described below.

[0054] The battery module 10 may also include a busbar frame 30, which is disposed outside the battery cell stack 100 and on which busbars 31 are mounted.

[0055] Busbar frames 30 can be disposed on both sides of the battery cell stack 100. At least one busbar 31 can be mounted on the busbar frame 30. Electrode leads 214 of the battery cell 200 can be connected to the busbar 31.

[0056] Battery module 10 may also include end cap 40.

[0057] The end cap 40 can be disposed outside the busbar frame 30. That is, the busbar frame 30 can be disposed between the battery cell stack 100 and the end cap 40.

[0058] End cap 40 can be attached to module frame 20. End cap 40 can cover two open end portions of module frame 20. End cap 40 can have opening 40H, and electrical connection of busbar 31 can be established through opening 40H. Busbar 31 of one battery module 10 can be electrically connected to another battery module 10, battery disconnect unit (BDU), or external load through opening 40H.

[0059] Figure 3 This is a plan view of a battery cell stack according to an embodiment of the present disclosure. Figure 4 This is a diagram illustrating the operation of a compression pad according to an embodiment of the present disclosure, and Figure 5 This is a cross-sectional view showing the compression pad and the internal portion of the battery cell according to an embodiment of the present disclosure.

[0060] A compression pad with the same compression ratio throughout the entire area has been used. Therefore, when expansion occurs within the battery cell, the pressure applied by the compression pad to the cell will deviate. More specifically, the pressure applied to the electrode contact side of the battery cell is less than the pressure applied to the central area of ​​the battery cell. Consequently, gas within the battery cell may move towards the electrode contacts, leading to lithium deposition and performance degradation.

[0061] To address this problem, the compression pad 300 according to embodiments of the present disclosure may include a main portion 310 and a side portion 320 with different compression ratios.

[0062] The main part 310 can extend along the length of the compression pad 300 and has a predetermined width.

[0063] The side portion 320 may be provided at the end portion of the main portion 310. The side portion 320 may form the end portion of the compression pad 300.

[0064] The side portion 320 may extend from the main portion 310. The length of the side portion 320 may be shorter than the length of the main portion 310. The width of the side portion 320 and the width of the main portion 310 may correspond to each other. The thickness of the side portion 320 and the thickness of the main portion 310 may correspond to each other. Here, correspondence may mean identical or similar.

[0065] The side portion 320 may have a lower compressibility than the main portion 310. That is, the side portion 320 may have a higher stiffness than the main portion 310. For example, the main portion 310 may comprise a urethane material, particularly a polyurethane material, and the side portion 320 may comprise a silicone material. However, the materials of the main portion 310 and the side portion 320 are not limited thereto.

[0066] The side portion 320 may overlap with a portion of the electrode tab 213 side region of the battery cell 200 with respect to the thickness direction of the compression pad 300. The electrode tab 213 can connect the electrode 211 of the electrode assembly 210 to the electrode lead 214. That is, the side portion 320 may overlap with a portion of the electrode lead 214 side region of the battery cell 200 with respect to the thickness direction of the compression pad 300.

[0067] In this embodiment, the electrode leads 214 can protrude from two sides of the battery cell 200 in opposite directions along its length. That is, the electrode tab 213 side region of the battery cell 200 can refer to the region at or near the two end portions of the battery cell 200. Therefore, the side portions 320 can be provided at the two end portions of the main portion 310. The side portions 320 can be provided on both sides with respect to the length of the battery cell 200, with the main portion 310 positioned between the two sides. The side portions 320 can form the two end portions of the compression pad 300. The side portions 320 can face the busbar frame 30 (see [link]) with respect to the length of the battery cell 200. Figure 2 ).

[0068] The electrode tab 213 side region of the battery cell 200 may have a smaller thickness than the central region of the battery cell 200. That is, there may be a thickness difference between the electrode tab 213 side region and the central region of the battery cell 200. In particular, this thickness difference may increase in the event of expansion within the battery cell 200. Therefore, when expansion occurs within the battery cell 200, the main portion 310 in the compression pad 300 is compressed more due to the pressure exerted through the central region of the battery cell 200, while the side portion 320 is compressed less due to the pressure exerted through the electrode tab 213 side region of the battery cell 200.

[0069] Relatedly, since the side portion 320 has a lower compressibility, i.e., higher stiffness than the main portion 310, the side portion 320 can generate a strong restoring force even when slightly compressed. Therefore, the side portion 320 can apply sufficient pressure to the electrode tab 213 side region of the battery cell 200 even when slightly compressed. Thus, the compression pad 300 can apply uniform pressure across the entire battery cell 200.

[0070] Meanwhile, the side portion 320 may include: an inner portion 321 connected to the main portion 310 and having a thickness corresponding to the main portion 310; and an outer portion 322 located outside the inner portion 321 and having an outwardly increasing thickness.

[0071] More specifically, refer to Figure 4 Before expansion occurs in the battery cell 200, the main portion 310 and the side portion 320 of the compression pad 300 may have an initial thickness t1 corresponding to each other. When expansion occurs in the battery cell 200, the main portion 310 has a compression thickness t2 smaller than the initial thickness t1, and the side portion 320 may be divided into an inner portion 321 and an outer portion 322.

[0072] The inner portion 321 may have a compression thickness t2 corresponding to that of the main portion 310. The outer portion 322 may have a thickness greater than the compression thickness t2, and this thickness may increase outwards. However, the maximum thickness of the outer portion 322 may be equal to or less than the initial thickness t1.

[0073] When the compression pad 300 separates from the plurality of battery cells 200, the thickness of the inner portion 321 and the thickness of the outer portion 322 can correspond to each other. That is, the inner portion 321 and the outer portion 322 can be restored to their initial thickness t1.

[0074] The main portion 310 may correspond to the central portion and the long edge portion 201 of the battery cell 200 (see [link]). Figure 2 ), and the side portion 320 may correspond to the short edge portion 202 of the battery cell 200 (see Figure 2 Here, "correspondence" can mean that they are in contact or close to each other. Therefore, it is possible to prevent excessive pressure from being applied to the long edge portion 201 of the battery cell 200 and to prevent lithium deposition at the long edge portion.

[0075] At the same time, refer to Figure 5 The electrode 211, particularly the positive electrode, of the electrode assembly 210 of the battery cell 200 may include an overlapping region that overlaps with the side portion 320 along the thickness direction of the compression pad 300. The electrode tab 213 may be connected to the overlapping region.

[0076] The length L1 of the overlapping region in the longitudinal direction of the battery cell 200 can be 5% to 10% of the length of the electrode 211. That is, the end region corresponding to 5% to 10% of the length of the electrode 211 can overlap with the side portion 320. Therefore, the battery cell 200 can be subjected to uniform pressure caused by the compression pad 300.

[0077] When the length L1 of the overlapping region is less than 5% of the length of electrode 211, sufficient pressure may not be applied to the electrode tab 213 side region of battery cell 200. When the length L1 of the overlapping region is greater than 10% of the length of electrode 211, excessive pressure may be applied to the central region of battery cell 200. In other words, when the length L1 of the overlapping region is outside the range of 5% to 10% of the length of electrode 211, uniform pressure may not be applied to battery cell 200.

[0078] Figure 6 This is a schematic diagram showing a compression pad and battery cell according to another embodiment of the present disclosure.

[0079] In this embodiment, the electrode leads 214 can protrude parallel to each other in the same direction from one side of the battery cell 200' in the longitudinal direction. That is, the region on the side of the electrode tab 213 of the battery cell 200' can refer to the region at or near one end portion of the battery cell 200'. Therefore, the side portion 320 can be provided at one end portion of the main portion 310. That is, the side portion 320 can form one end portion of the compression pad 300, and the other end portion of the compression pad 300 can be part of the main portion 310.

[0080] The foregoing description has illustrated the technical aspects of this disclosure by way of example, and those skilled in the art to which this disclosure pertains will be able to make various modifications and variations without departing from the essential features of this disclosure.

[0081] Therefore, the disclosed embodiments are provided to describe the technical aspects of this disclosure and are not intended to be limiting, and the technical scope of this disclosure is not limited to these embodiments.

[0082] The scope of protection of this disclosure shall be interpreted by the appended claims, and shall be interpreted as including all technical spirit within the equivalent scope within the scope of protection of this disclosure.

[0083] [List of reference numerals]

[0084] 10: Battery Module 20: Module Frame

[0085] 30: Busbar frame; 40: End cap

[0086] 100: Battery cell stack 200: Battery cell

[0087] 210: Electrode assembly 211: Electrode

[0088] 212: Separator; 213: Electrode connector

[0089] 214: Electrode leads; 220: Outer packaging.

[0090] 300: Compression Pad; 310: Main Component

[0091] 320: Side section; 321: Interior section

[0092] 322: External Part

Claims

1. A battery cell stack, comprising: Multiple battery cells are arranged in parallel to each other, each battery cell including an electrode assembly and an outer packaging, the electrode assembly having electrode tabs, and the outer packaging accommodating the electrode assembly; as well as A compression pad is placed between the plurality of battery cells. The compression pad includes: Main parts; and A side portion is disposed at the end portion of the main portion and has a lower compression ratio than the main portion. The side portion overlaps with a portion of the electrode tab side region of the battery cell in the thickness direction of the compression pad.

2. The battery cell stack according to claim 1, in, The electrode assembly includes electrodes and spacers arranged in an alternating manner, and The electrodes include: An overlapping region, wherein the electrode tab is connected, and the overlapping region overlaps with the side portion along the thickness direction of the compression pad.

3. The battery cell stack according to claim 2, in, The length of the overlapping region in the longitudinal direction of the battery cell is 5% to 10% of the length of the electrode.

4. The battery cell stack according to claim 1, in, The side portion includes: An internal portion, the internal portion being connected to the main portion and having a thickness corresponding to the main portion; and An outer portion, located outside the inner portion, has an outwardly increasing thickness.

5. The battery cell stack according to claim 4, in, When the compression pad separates from the plurality of battery cells, the thickness of the inner portion and the thickness of the outer portion correspond to each other.

6. The battery cell stack according to claim 1, in, The main component includes polyurethane material, and The side portion includes a silicone resin material.

7. The battery cell stack according to claim 1, in, The side portions are arranged on both sides along the length of the battery cell, wherein the main portion is located between the two sides.

8. The battery cell stack according to claim 1, in, The main portion corresponds to the central portion and the long edge portion of the battery cell, and The side portion corresponds to the short edge portion of the battery cell.

9. A battery module, comprising: Module housing; as well as A battery cell stack, which is housed within the module housing. The battery cell stack includes: Multiple battery cells arranged parallel to each other, each battery cell including an electrode assembly and an outer packaging, the electrode assembly having electrode tabs, and the outer packaging housing the electrode assembly; and A compression pad is placed between the plurality of battery cells, and The compression pad includes: Main parts; and A side portion is disposed at the end portion of the main portion and has a lower compression ratio than the main portion. The side portion overlaps with a portion of the electrode tab side region of the battery cell in the thickness direction of the compression pad.

10. The battery module according to claim 9, further comprising: A busbar frame is disposed outside the battery cell stack, and busbars are mounted on the busbar frame. The battery cell further includes: Electrode leads, which are connected to the electrode contacts, protrude outward from the outer packaging and are connected to the busbar. The side portion faces the busbar frame along the length direction of the battery cell.

11. A compression pad disposed between a plurality of battery cells arranged parallel to each other, each battery cell including an electrode assembly and an outer packaging, the electrode assembly having electrode tabs, the outer packaging accommodating the electrode assembly, the compression pad comprising: Main parts; as well as A side portion is disposed at the end portion of the main portion and has a lower compression ratio than the main portion. The side portion overlaps with a portion of the electrode tab side region of the battery cell in the thickness direction of the compression pad.

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