Battery module and battery pack

Abstract

The invention discloses a battery module and a battery pack. The battery module comprises a battery pack, and the battery pack comprises a plurality of battery cells which are sequentially arranged along a first direction; the end plate assemblies are arranged at the two ends of the battery pack in the first direction, each end plate assembly comprises an end plate and a buffer layer, the buffer layers are arranged on the sides, close to the battery pack, of the end plates, and the buffer layers are attached to the corresponding battery cells; a concave part is arranged in the middle area of the side, facing the buffer layer, of the end plate, a convex part is arranged in the middle area of the side, facing the end plate, of the buffer layer, and the concave part and the convex part are correspondingly arranged in a matched mode. The battery pack comprises a box body, a mounting cavity is formed in the box body, and supporting beams are arranged at the two ends of the mounting cavity in the first direction; the battery pack is mounted in the adaptive mounting cavity, one side, far away from the battery pack, of the end plate is connected with the supporting beam, and the other side, in the third direction, of the battery module is fixed in the box body through heat-conducting glue. Through the buffer structure, the expansion uniformity of the battery cell is improved, and local stress concentration is reduced, so that the performance of the battery cell is ensured, and the long cycle life of the battery module and the battery pack is maintained.

Description

A battery module and battery pack Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a battery module and battery pack. Background Technology

[0002] With the rapid development of new energy vehicles and the energy storage industry, the reliability, cycle life, and assembly efficiency of power battery packs have become core technical indicators. A power battery pack typically consists of multiple cells arranged in rows with end plates at both ends to form a battery module. These battery modules are then installed inside a housing to constitute the power battery pack. Among these, prismatic cells are widely used in various types of power battery packs due to their high energy density and strong structural stability.

[0003] However, the performance stability of prismatic cells throughout their entire lifecycle is significantly affected by the endplate structure, and existing endplate structures face technical bottlenecks in adapting to cell characteristics. Specifically, after electrolyte injection and during multiple cycles of use, prismatic cells exhibit an uneven bulging phenomenon with an "arched thickness distribution," meaning the expansion in the central area of ​​the cell is greater than that in the surrounding areas. Existing endplates generally use rigid structures with uniform thickness, which cannot accommodate the uneven expansion of the cell. This leads to a large-area stress imbalance and localized stress concentration within the cell, which not only accelerates the degradation of cell performance but also affects the cycle life of the power battery pack.

[0004] Therefore, there is an urgent need for a new type of end plate structure to adapt to the uneven expansion characteristics of the battery cells in order to meet the requirements of power battery packs for long cycle life. Summary of the Invention

[0005] One of the objectives of this invention is to disclose a battery module that improves the uniformity of cell expansion, reduces local stress concentration in the cell, and balances the stress on the large surface of the cell by setting a buffer structure on the end plate, thereby ensuring the performance of the cell and maintaining the life of the battery module.

[0006] The second objective of this invention is to disclose a battery pack that utilizes the aforementioned battery module structure to avoid performance degradation caused by uneven cell swelling during operation, thereby ensuring a long cycle life for the battery pack.

[0007] To achieve the above objectives, one aspect of the present invention discloses a battery module, comprising: a battery pack, the battery pack including a plurality of battery cells arranged sequentially along a first direction; an end plate assembly, the end plate assembly being disposed at both ends of the battery pack in the first direction, the end plate assembly including an end plate and a buffer layer, the buffer layer being disposed on the side of the end plate close to the battery pack, and the buffer layer being fitted to its corresponding battery cell; a recess is provided in the middle region of the end plate facing the buffer layer, and a protrusion is provided in the middle region of the buffer layer facing the end plate, the recess and the protrusion being correspondingly adapted to each other.

[0008] As an optional implementation, the recess includes a first arcuate groove disposed along a second direction in the middle region of the end plate facing the buffer layer, and the protrusion includes a first arcuate protrusion disposed along a second direction in the middle region of the buffer layer facing the end plate; and / or, the recess includes a second arcuate groove disposed along a third direction in the middle region of the end plate facing the buffer layer, and the protrusion includes a second arcuate protrusion disposed along a third direction in the middle region of the buffer layer facing the end plate; the first direction, the second direction, and the third direction are perpendicular to each other, and the first direction and the second direction are parallel to the mounting plane of the battery module.

[0009] As an optional implementation, the end plate includes an end plate body and a recess, the recess being recessed away from the buffer layer relative to the end plate body, and the end plate body being disposed on the periphery of the recess; the buffer layer includes a buffer body and a protrusion, the protrusion being protruded closer to the end plate than the buffer body, and the buffer body being disposed on the periphery of the protrusion; the recess and the protrusion, and the end plate body and the buffer body are all provided in a concave-convex fit.

[0010] As an optional implementation, the thickness D1 of one end of the end plate body in the third direction along the first direction is 1~10mm, the thickness D2≤D1 of the other end of the end plate in the third direction along the first direction, the thickness D3≥0.5mm of the concave part along the first direction, and both D1 and D2 are greater than D3; the thickness d1 of both ends of the buffer body in the third direction along the first direction is 1~10mm, the thickness d2 of the convex part along the first direction, and D1+d1=D3+d2.

[0011] As an optional implementation, at least one end of the end plate in the third direction is provided with a chamfer structure, and the chamfer structure is provided on the side of the end plate away from the buffer layer.

[0012] As an optional implementation, multiple cells of the battery pack are connected in series and / or in parallel via multiple electrical connectors. The multiple electrical connectors are located on one side of the battery pack in a third direction, and the multiple electrical connectors are distributed at both ends of the battery pack in a second direction. In the second direction, the distance between the corresponding ends of the electrical connectors and the protrusions is set.

[0013] As an optional implementation, the thickness of any position of the protrusion along the first direction gradually increases as the distance between it and the edge of the protrusion increases, and the gradual change process satisfies any one of the following function curves: linear function, quadratic function, tangent function, or piecewise function.

[0014] The second invention discloses a battery pack, comprising: a housing, a mounting cavity provided in the housing, and support beams provided at both ends of the mounting cavity in a first direction; the aforementioned battery module, wherein the battery pack is installed in the appropriate mounting cavity, and the side of the end plate away from the battery pack is connected to the support beam, and the other side of the battery module in a third direction is fixed to the housing by thermally conductive adhesive.

[0015] As an optional implementation, an overflow channel is provided on the side of the end plate near the support beam, and the overflow channel is provided and connected to the thermally conductive adhesive at the other end of the end plate in the third direction. The overflow channel extends along the second direction and / or the third direction.

[0016] As an optional implementation, the adhesive overflow channel includes a first adhesive overflow channel extending in a third direction and a second adhesive overflow channel extending in a second direction. Multiple first adhesive overflow channels are spaced apart in the second direction. One end of each of the multiple first adhesive overflow channels is connected to the thermally conductive adhesive, and the other end of each of the multiple first adhesive overflow channels is connected to the second adhesive overflow channel. One end of the first adhesive overflow channel is located close to the flared opening of the thermally conductive adhesive.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the battery module of the present invention, a buffer layer is provided on the side of the end plate near the battery pack. The convex part of the buffer layer is provided corresponding to the middle area of ​​the cell, and the peripheral side of the convex part is provided corresponding to the peripheral side of the large surface of the cell. Thus, the cooperation between the convex structure and the peripheral structure of the buffer layer can be used to deal with the uneven expansion of the cell, reduce the problem of local stress concentration of the cell, and balance the stress on the large surface of the cell. In addition, the buffer layer also has the function of shock absorption, which can avoid damage to the cell from external impacts. Thus, the end plate assembly with the buffer structure is beneficial to improving the stability of the cell performance to maintain the cycle life of the battery module.

[0018] (2) The battery pack of the present invention adopts the above-mentioned battery module structure, which can avoid the performance degradation caused by uneven swelling of the cells during operation, thereby improving the operational stability of the battery pack and ensuring the long cycle life of the battery pack. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 is a structural schematic diagram of the battery module of the present invention; Figure 2 is a structural schematic diagram of the end plate assembly of the present invention; Figure 3 is an exploded view of the first embodiment of the end plate assembly of the present invention; Figure 4 is an exploded view of the second embodiment of the end plate assembly of the present invention; Figure 5 is a side exploded view of the first embodiment of the end plate assembly of the present invention; Figure 6 is an enlarged view of point A in Figure 5; Figure 7 is an enlarged view of point B in Figure 5; Figure 8 is an enlarged view of point C in Figure 5; Figure 9 is a partial top view of the battery module of the present invention; Figure 10 is a structural schematic diagram of the battery pack of the present invention; Figure 11 is an exploded view of the battery pack of the present invention; Figure 12 is a partial structural schematic diagram of the battery pack of the present invention; Figure 13 is a structural schematic diagram of the thermally conductive adhesive applied to the housing of the present invention; Figure 14 is a structural schematic diagram of the end plate assembly and the strip-shaped thermally conductive adhesive of the present invention.

[0021] Key reference numerals in the attached drawings: 1. Battery pack; 11. Cell; 2. End plate assembly; 21. End plate; 211. Recess; 2111. First arc-shaped groove; 2112. Second arc-shaped groove; 212. End plate body; 213. Chamfered structure; 2131. First chamfered bevel; 2132. Second chamfered bevel; 214. Glue overflow channel; 2141. First glue overflow channel; 2142. Second glue overflow channel; 22. Buffer layer; 221. Protrusion; 2211. First arc-shaped protrusion; 2212. Second arc-shaped protrusion; 222. Buffer body; 3. CCS assembly; 31. Electrical connection piece; 4. Housing; 41. Mounting cavity; 42. Support beam; 5. Thermally conductive adhesive. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0025] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0026] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0027] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0028] Please refer to Figure 1. This application embodiment provides a battery module, which includes a battery pack 1 and an end plate assembly 2. The end plate assembly 2 is disposed at both ends of the battery pack 1 in a first direction. The first direction is the X direction as shown in Figure 1, which is generally the length direction of the battery module and / or the battery pack 1.

[0029] A battery module may have only one battery pack 1 or at least two battery packs 1. When the battery module has at least two battery packs 1, the at least two battery packs 1 are arranged side by side along a second direction, which is the Y direction as shown in Figure 1, and is generally the width direction of the battery module and / or battery pack 1. Regardless of the number of battery packs 1, the battery pack 1 includes a plurality of cells 11 arranged sequentially along a first direction. In this embodiment, the cell 11 is described using a square cell as an example. In practical applications, the cell 11 can also be a cylindrical cell, etc., as long as the structural layout is adjusted accordingly. The battery cell 11 includes two large surfaces arranged opposite each other. When multiple battery cells 11 are arranged sequentially along the first direction, the large surfaces of two adjacent battery cells 11 are arranged correspondingly. A heat insulation buffer pad is provided between two adjacent battery cells 11. The heat insulation buffer pad has the function of buffering and shock absorption, which can absorb the expansion of the battery cell 11 and reduce the damage to the battery cell 11 caused by external impact. At the same time, the heat insulation buffer pad also has the function of heat insulation, which can reduce the heat transfer between two adjacent battery cells 11 and prevent the adjacent battery cells 11 from having a cascading effect when the temperature of any battery cell 11 is too high or even thermal runaway.

[0030] Multiple battery cells 11 in the battery pack 1 are arranged along a first direction, and end plate assemblies 2 are provided at both ends of the battery pack 1 in the first direction. Referring to Figure 2, the end plate assembly 2 includes an end plate 21 and a buffer layer 22. The buffer layer 22 is located on the side of the end plate 21 close to the battery pack 1, and the buffer layer 22 is attached to its corresponding battery cell 11. An end plate 21 is provided at each end of the battery pack 1 in the first direction to isolate the battery pack 1 in the first direction. The end plate 21 is a rigid structure and can be made of materials such as PC, nylon PA, ABS, etc., or it can be a plastic with a mixture of multiple components, such as ABS+PC. The end plate 21 has a small amount of deformation and is difficult to absorb the expansion of the battery pack 1, especially the battery cells 11 at the end in the first direction, and is difficult to mitigate the impact damage from external forces. The buffer layer 22 can improve this defect. A buffer layer 22 is sandwiched between the end plate 21 at the corresponding end in the first direction and the battery cell 11. Both sides of the buffer layer 22 in the first direction are in contact with the large surface of the corresponding battery cell 11 and the side of the end plate 21. Thus, the buffer layer 22 can absorb the expansion of the battery pack 1, especially its corresponding battery cell 11, and reduce the damage to the battery cell 11 caused by external impacts by utilizing the buffer and shock absorption function of the buffer layer 22. In this way, the cooperation between the buffer layer 22 and the heat insulation buffer pad can absorb the expansion of each battery cell 11 in the battery pack 1 and effectively buffer and dampen external impacts to ensure the safety performance of the battery pack 1.

[0031] The buffer layer 22 and the end plate 21 can be fixed by bonding or injection molding. The buffer layer 22 and the heat insulation buffer pad can be molded by silicone foaming process to form a porous foam structure with good resilience and mechanical strength to meet the needs of cushioning and shock absorption, and can withstand external impact.

[0032] It is worth noting that during the charge and discharge cycle, the expansion of the central area of ​​the large surface of the battery cell 11 is generally greater than that of the peripheral area. This uneven expansion of the large surface of the battery cell 11 can easily lead to local stress concentration and accelerate the degradation of its performance.

[0033] Based on this problem, referring to Figure 3, in this embodiment, the end plate 21 facing the buffer layer 22 has a recess 211 in the middle region, and the buffer layer 22 facing the end plate 21 has a protrusion 221 in the middle region. The recess 211 and the protrusion 221 are correspondingly adapted to each other. The cooperation between the recess 211 and the protrusion 221 can ensure the fit between the end plate 21 and the buffer layer 22. The protrusion 221 is set in the middle region of the large surface of the cell 11, and the periphery of the protrusion 221 is set in the periphery of the large surface of the cell 11. Thus, the cooperation of the protrusion of the buffer layer 22 and its periphery can be used to deal with the uneven expansion of the cell 11, reduce the problem of local stress concentration in the cell 11, and balance the stress on the large surface of the cell 11. This can avoid the performance degradation of the cell 11 caused by uneven expansion, thereby maintaining the cycle life of the battery module.

[0034] It should be noted that the concave-convex mating structure of the end plate 21 and the buffer layer 22 in this embodiment is mainly intended to address the uneven expansion of the battery cell 11. Therefore, generally, the protrusion 221 only needs to correspond to the middle area of ​​the large surface of the battery cell 11 and protrude towards the end plate 21; the specific structure is not limited. However, since the peripheral edges of the battery cell 11 do not change significantly when the large surface expands, and the middle area transitions to the center of the large surface in an arc shape, the protrusion 221 can be designed as an arc-shaped transition structure to better adapt to the shape of the large surface expansion of the battery cell 11, thereby achieving the best buffering effect. The fact that the protrusion 221 protrudes towards the end plate 21 rather than the battery cell 11 is to ensure that the end plate 21, the buffer layer 22, and the battery pack 1 are sequentially fitted together, thereby achieving stable assembly of the battery module.

[0035] Referring to Figure 4, the concave-convex fit structure between the end plate 21 and the buffer layer 22 can be as follows: the recess 211 includes a first arc-shaped groove 2111 located in the middle region of the end plate 21 facing the buffer layer 22 along the second direction, and the convex part 221 includes a first arc-shaped protrusion 2211 located in the middle region of the buffer layer 22 facing the end plate 21 along the second direction. Alternatively, the recess 211 can include a second arc-shaped groove 2112 located in the middle region of the end plate 21 facing the buffer layer 22 along the third direction, and the convex part 221 can include a second arc-shaped protrusion 2212 located in the middle region of the buffer layer 22 facing the end plate 21 along the third direction. Another option is that the concave-convex fit structure between the end plate 21 and the buffer layer 22 can be provided in both the second and third directions, i.e., the first arc-shaped groove 2111 and the first arc-shaped protrusion 2211, and the second arc-shaped groove 2112 and the second arc-shaped protrusion 2212 are both provided. Among them, the third direction, as shown in Figure 1, is the Z direction, which is generally the height direction of the battery module and / or battery pack 1. The first direction, the second direction, and the third direction are perpendicular to each other, and the first direction and the second direction are parallel to the mounting plane of the battery module.

[0036] The first arc-shaped protrusion 2211 can gradually protrude from both ends of the buffer layer 22 in the second direction towards the middle area, and the first arc-shaped groove 2111 can be matched with the arc-shaped recess of the first arc-shaped protrusion 2211. The second arc-shaped protrusion 2212 can gradually protrude from both ends of the buffer layer 22 in the third direction towards the middle area, and the second arc-shaped groove 2112 can be matched with the arc-shaped recess of the second arc-shaped protrusion 2212. However, since the expansion of the large surface of the cell 11 is not obvious, especially the expansion of its four corners, the starting ends of the first arc-shaped protrusion 2211 and the second arc-shaped protrusion 2212 can avoid the peripheral area of ​​the buffer layer 22 facing the end plate 21, especially the four corners. This is beneficial to reduce the processing technology and cost, and facilitates the stable assembly of other components of the battery module, such as the CCS module 3.

[0037] The concave-convex mating structures of the three end plates 21 and buffer layers 22 can be selected according to the expansion characteristics of the cells 11 in the specific battery module. It is preferable to set concave-convex mating structures in both the second and third directions to further improve the expansion uniformity of the cells 11. If the concave-convex mating structure is set in only one direction, the battery module has a large expansion characteristic in the first direction and a small expansion degree in the third direction. Moreover, after the battery module is assembled, the top will be pressed by the top cover of the housing 4 to form a rigid constraint. Therefore, it is preferable to set the concave-convex mating structure in the third direction.

[0038] Furthermore, regardless of the position and shape of the convex-concave mating structure between the end plate 21 and the buffer layer 22, the corresponding end faces of the end plate 21 and the buffer layer 22 must be fitted together. The end plate 21 includes an end plate body 212 and a recess 211. The recess 211 is recessed away from the buffer layer 22 relative to the end plate body 212, and the end plate body 212 is located on the periphery of the recess 211. The buffer layer 22 includes a buffer body 222 and a protrusion 221. The protrusion 221 is protruding closer to the end plate 21 relative to the buffer body 222, and the buffer body 222 is located on the periphery of the protrusion 221. The recess 211 and the protrusion 221, as well as the end plate body 212 and the buffer body 222, are all convex-concave mating. In this way, not only are the recessed portion 211 and the protruding portion 221 tightly connected, but the end plate body 212 and the buffer body 222 can also be firmly connected, thereby ensuring the connection stability between the end plate 21 and the buffer layer 22, so that the end plate assembly 2 can be firmly set at both ends of the battery pack 1.

[0039] In the third direction, the thickness of both ends of the end plate 21 is equal, that is, the two ends of the end plate 21 on the side away from the buffer layer 22 in the third direction are on the same plane, which facilitates processing. Alternatively, the thickness of one end of the end plate 21 is greater than the thickness of the other end of the end plate 21. Specifically, the thickness of the top end of the end plate 21 in the third direction is greater than the thickness of the bottom end. That is, the bottom end of the end plate 21 on the side away from the buffer layer 22 in the third direction is recessed compared to the top end. The top end of the end plate 21 in the third direction has greater structural strength, so that when the battery module is assembled, the top end of the end plate 21 in the third direction can form a greater compressive force with the support beam 42, preventing the battery module from shaking or even detaching from the battery pack housing 4 due to vibration.

[0040] Referring to Figure 5-8, the thickness D1 of one end of the end plate body 212 in the third direction along the first direction is 1~10mm, the thickness D2 ≤ D1 of the other end of the end plate 21 in the third direction along the first direction, and the thickness D3 ≥ 0.5mm of the recess 211 in the first direction, with both D1 and D2 being greater than D3. D1 is the thickness of the top part of the end plate 21 in the third direction without the recessed structure, i.e., the top thickness of the end plate body 212, which can stably support the CCS component 3 on top. D2 is the thickness of the bottom part of the end plate 21 in the third direction without the recessed structure, i.e., the bottom thickness of the end plate body 212, which can be set to D2=D1 or D2<D1 according to the assembly process requirements of the battery module. D3 is the thickness of the area of ​​the end plate 21 with the recessed structure, i.e., the thickness of the recess 211. The arc-shaped gradient structure of the recess 211 needs to ensure that the thickness of each part is not less than 0.5mm to guarantee the structural strength of the end plate 21.

[0041] The thickness d1 of both ends of the buffer body 222 in the third direction along the first direction is 1~10mm, so as to play a basic buffering role for the peripheral area of ​​the large surface of the battery cell 11. The thickness of the protrusion 221 along the first direction is d2, D1+d1=D3+d2, so as to ensure the tight fit between the buffer layer 22 and the end plate 21.

[0042] It should be noted that the above dimensions are limitations imposed by the embodiments of this application in conjunction with conventional battery module structures. For different types of battery modules, the dimensions of each part of the end plate 21 and buffer layer 22 can be adjusted according to actual needs, as long as the buffering and stable assembly effect is guaranteed.

[0043] Referring to Figures 5-7, at least one end of the end plate 21 in the third direction has a chamfered structure, which is located on the side of the end plate 21 away from the buffer layer 22. The chamfered top end of the end plate 21 in the third direction avoids obstruction by the grippers during assembly, facilitating the grippers' gripping of the battery module and its assembly into the housing 4. It also avoids obstruction by the tilted structure of the blister tray during CCS component 3 assembly, and helps reduce the size of the battery module, thus improving assembly efficiency. The chamfered bottom end of the end plate 21 in the third direction facilitates the connection and engagement between the battery module and the support beam 42 when the battery module is assembled into the housing 4, improving installation convenience.

[0044] Regardless of whether the chamfer structure is located at the top, bottom, or both ends of the end plate 21 in a third direction, the chamfer structure is always located on the side of the end plate 21 away from the buffer layer 22, so as not to affect the assembly effect between the end plate 21 and the buffer layer 22.

[0045] The chamfer structure can be a rounded corner structure or a chamfered bevel structure, etc. In order to better adapt to the assembly process of the battery module, the chamfer structure in this embodiment is set as a chamfered bevel, and both ends of the end plate 21 in the third direction are provided with chamfered bevels. The angle of the chamfered bevel is set as an obtuse angle, and after the chamfered bevel is set, both ends of the end plate 21 in the third direction retain a certain thickness so that the force applied to the end can be effectively transferred, thereby ensuring the structural strength of the end plate 21.

[0046] Specifically, one end of the end plate 21 in the third direction is provided with a first chamfered bevel 2131. The first chamfered bevel 2131 is located on the side of the end plate 21 away from the buffer layer 22. The height of the first chamfered bevel 2131 in the third direction satisfies 0 < H1 < 10 mm. After chamfering, the thickness D4 of the end of the end plate body 212 in the third direction in the first direction is ≥ 0.3 mm. The angle α1 of the first chamfered bevel 2131 is 180° - arctan((D1-D4) / H1). The end plate 21 has a second chamfered bevel 2132 at the other end in the third direction. The second chamfered bevel 2132 is located on the side of the end plate 21 away from the buffer layer 22. The height of the second chamfered bevel 2132 in the third direction satisfies 0 < H2 < 10 mm. The thickness D5 of the other end of the end plate body 212 in the third direction after chamfering is ≥ 0.3 mm in the first direction. The angle α2 of the second chamfered bevel 2132 is 180° - arctan((D2-D5) / H2). This is only a size limitation for a conventional end plate 21. For different types of battery modules, the size of each part of the end plate 21 can be adjusted according to actual needs.

[0047] In addition to the battery pack 1 and end plate assembly 2 mentioned above, the battery module also includes a CCS assembly 3 to connect the individual cells 11 in series and / or in parallel, and to collect signals such as temperature and voltage of each cell 11 and transmit them to the battery management system (BMS). The BMS then monitors and manages the performance of each cell, ensuring the safe operation of the battery module. Referring to Figures 10-11, the CCS assembly 3 includes a separator, electrical connectors 31, and a circuit board. The separator is generally made of plastic and is positioned corresponding to the positive and negative terminals at the third-direction top of the cell 11. It serves both as electrical insulation and to support the installation of components such as the electrical connectors 31 and the circuit board. Multiple cells 11 of the battery pack 1 are connected in series and / or in parallel via multiple electrical connectors 31. These connectors 31 are located on one side of the battery pack 1 in the third direction and distributed at both ends of the battery pack 1 in the second direction. After passing through the separator, the positive and negative terminals of each cell 11 are connected in series and / or in parallel via the electrical connectors 31. The circuit board is electrically connected to the electrical connector 31 to accurately collect signals such as voltage and temperature of each battery cell 11.

[0048] Referring to Figures 1 and 9, after the CCS component 3 is assembled, the electrical connector 31 and the corresponding end of the protrusion 221 are spaced apart in the second direction. The protrusion 221 is located in the middle region of the buffer layer 22. The periphery of the buffer layer 22, especially the four corner regions, are not protruded to form the buffer body 222. The end of the protrusion 221 in the second direction is connected to the buffer body 222. The distance between this connection and the corresponding end of the electrical connector 31 is set, and this distance m is not less than 5mm, so as to limit the initial protrusion of the buffer layer 22, delay the electrical connector 31 from being pulled and torn by the expansion of the cell 11 in the first direction, thereby ensuring the safe assembly of the battery module.

[0049] Regardless of the structural or dimensional limitations imposed on the components of the battery module as described above, the core purpose of the buffer layer 22 in this embodiment is to utilize the cooperation between the protrusion 221 and the buffer body 222 to cope with the uneven expansion of the battery cell 11, thereby ensuring stable battery module performance and a longer cycle life. Since the expansion thickness of the central region of the battery cell 11 is greater than that of the peripheral edge region when the cell 11 expands significantly, and the thickness is gradually varying, the thickness of the corresponding buffer layer 22 also gradually varies along the first direction. Furthermore, the thickness variation characteristics of the protrusion 221 are coupled with the nonlinear structural characteristics of the buffer material, enabling the buffer layer 22 to possess a deformation response capability adapted to the expansion curve of the battery cell. Ideally, the buffer layer 22 has the characteristics of low initial stiffness, a wide plateau region, and high resilience, which can smoothly absorb the expansion force of the battery cell 11. However, during battery module assembly, a certain pre-tightening force needs to be applied to the battery module using tooling. Therefore, the thickness of the buffer layer 22 needs to achieve the expected compressive deformation based on the pre-tightening force to provide effective initial pressure. Therefore, based on different application scenarios, the thickness of any position of the protrusion 221 along the first direction gradually increases as the distance between it and the edge of the protrusion 221 increases, and the gradual change process satisfies any one of the following function curves: linear function, quadratic function, tangent function, or piecewise function.

[0050] With T base The thickness at the connection between the protrusion 221 and the buffer body 222 represents the minimum thickness of the buffer layer 22; T represents the thickness at the connection between the protrusion 221 and the buffer body 222. max The thickness of the center of the protrusion 221 is the maximum thickness of the buffer layer 22; H represents the distance from the connection between the protrusion 221 and the buffer body 222 to the center of the protrusion 221; x represents the distance from a certain position of the protrusion 221 to the connection between the protrusion 221 and the buffer body 222, where 0 ≤ x ≤ H.

[0051] When the thickness of buffer layer 22 changes linearly, T(x) = T base + (T max T base For example, the thickness T at the connection between the protrusion 221 and the buffer body 222. base The thickness T at the center of the protrusion 221 is 1mm. max If the thickness is 3mm, then T(x) = 1 + 2 / H*x. When x = 0, T(0) = 1 = T base Therefore, T0 can be used to replace T. base ;2 / H or (T max T base H represents the slope of the linear gradient, which can be replaced by k. Thus, the thickness of the buffer layer 22 can satisfy the linear gradient function curve of T(x) = T0 + kx.

[0052] Based on the above example, the following table shows the characteristics of the thickness variation of buffer layer 22 when it satisfies different types of function curves.

[0053]

[0054] The design of the thickness variation of the buffer layer 22 requires the selection of the corresponding function curve type based on the application scenario. Its core objective is to make the stress-strain curve of the buffer layer 22 best match the expansion force curve of the cell 11, so that the buffer layer 22 and the cell 11 maintain a stable and uniform contact pressure throughout the entire battery module life, ensuring the safe operation of the battery module and its high performance.

[0055] Referring to Figure 10, this embodiment of the application also provides a battery pack, including a housing 4 and the aforementioned battery module. Referring to Figures 11-12, the housing 4 has a mounting cavity 41. There may be only one mounting cavity 41, or two or more. Support beams 42 are provided at both ends of the mounting cavity 41 in a first direction. When the battery module is assembled in the mounting cavity 41, the support beams 42 are used to fix the two ends of the battery module in the first direction. Specifically, the battery pack 1 is installed in the suitable mounting cavity 41, and the side of the end plate 21 away from the battery pack 1 is connected to the support beam 42. The other side of the battery module in a third direction is fixed to the housing 4 via thermally conductive adhesive 5. The end plate assembly 2 is located between the battery pack 1 and the support beam 42. The end plate 21 is fitted to the support beam 42, and the buffer layer 22 is fitted to the battery pack 1. This allows the concave-convex fit structure of the end plate 21 and the buffer layer 22 to prevent performance degradation caused by uneven expansion of the battery cells 11 during operation, thereby improving the operational stability of the battery pack and ensuring a long cycle life.

[0056] The bottom of the housing 4 is provided with thermally conductive adhesive 5, which is in the form of a strip as shown in Figure 13 before assembly. During the assembly of the battery module into the housing 4, the strip is pressed open to form a flat thermally conductive adhesive 5, thereby utilizing the thermally conductive adhesive 5 for heat exchange and ensuring the bonding strength between the battery module and the housing 4. When assembling the battery module, the end of the battery module in the first direction is inserted into the housing 4 by excessive compression with the support beam 42. That is, the battery module is first compressed until the dimension in the first direction is smaller than the distance between the two support beams 42 in the first direction before being inserted into the housing 4. After being inserted to 1 / 3-1 / 2 of the height, the clamping device is released, and the module is pressed down into the housing 4 from the top in the third direction. During the pressing process, the end plate assembly 2 and the support beam 42 are tightly fitted to form a sealed space. When the thermally conductive adhesive 5 is pressed open by the battery module, the internal gas cannot be discharged, forming a cavitation area, which affects the bonding strength between the battery module and the housing 4 and the heat exchange between the battery module and the bottom cold plate.

[0057] Based on this, referring to Figures 1 and 11, an overflow channel 214 is provided on the side of the end plate 21 near the support beam 42. The overflow channel 214 is located at the other end of the end plate 21 in the third direction and is connected to the thermally conductive adhesive 5. The overflow channel 214 extends along the second direction and / or the third direction. There may be one, two or more overflow channels 214, depending on the venting requirements. After the battery module is inserted into the housing 4, a sealed space is formed between the bottom of the battery module and the housing 4. When the thermally conductive adhesive 5 is squeezed, the internal gas is discharged through the overflow channel 214 and the overflow channel 214 contains the overflowing thermally conductive adhesive 5, avoiding the formation of cavitation areas between the battery module and the housing 4, improving the bonding strength between the battery module and the housing 4 and the heat exchange between the battery module and the bottom cold plate; some of the thermally conductive adhesive 5 overflows through the overflow channel 214 to the space between the end plate 21 and the cell 11, forming an overflow layer of a certain height, increasing the bonding area between the end plate 21 and the cell 11, and increasing the overall rigidity. Furthermore, the overflow channel 214, together with the concave and convex structure of the end plate 21 and the buffer layer 22, can better cooperate in bearing force, so as to ensure stable installation of the battery module and improve space utilization.

[0058] The strip-shaped thermally conductive adhesive 5 needs to be evenly applied to ensure effective adhesion between the battery module and the bottom cold plate. The thermally conductive adhesive 5 can be made of polyurethane, silicone, gel, etc., which have good bonding strength and thermal conductivity to improve the bonding strength and heat exchange effect between the battery module and the cold plate. After the battery module is placed into the housing 4, a small amount of thermally conductive adhesive 5 overflows into the overflow channel 214. Since the upper part of the end plate 21 in the third direction is used for gripping by claws, and the middle part of the end plate 21 is the thinnest to fit the buffer layer 22, the overflow channel 214 is located in the lower part of the end plate 21 in the third direction. This also facilitates close contact between the upper part of the end plate 21 and the support beam 42, improving structural strength.

[0059] The adhesive overflow channel 214 can be arranged along a second direction, along a third direction, or in combination with the second direction, or in an inclined or curved shape. Referring to Figure 14, in this embodiment of the application, the adhesive overflow channel 214 includes a first adhesive overflow channel 2141 extending along a third direction and a second adhesive overflow channel 2142 extending along the second direction. Multiple first adhesive overflow channels 2141 are spaced apart along the second direction. One end of each of the multiple first adhesive overflow channels 2141 is connected to the thermally conductive adhesive 5, and the other end of each of the multiple first adhesive overflow channels 2141 is connected to the second adhesive overflow channel 2142. One end of the first adhesive overflow channel 2141 is flared near the opening of the thermally conductive adhesive 5.

[0060] One end of the first overflow channel 2141 is flared towards the bottom thermally conductive adhesive 5. This design prevents blockage at the beginning of the overflow channel 214 and allows for a larger amount of thermally conductive adhesive 5 to be accommodated at the bottom, thereby improving the structural strength of the bottom of the battery module. The flared structure can be triangular, trapezoidal, fan-shaped, etc. As it extends away from the bottom thermally conductive adhesive 5, the flow cross-section gradually decreases, generally maintaining an inclination angle of 45-150°. As shown in Figure 14, the inclination angle is 60°, which facilitates the flow and venting of the thermally conductive adhesive 5.

[0061] The overflow channel 214 is arranged in sequence with a flared area, a main body area of ​​the first overflow channel 2141, and a second overflow channel 2142, and the width decreases in sequence, which is conducive to smooth overflow and venting. The first overflow channel 2141 is mainly used for overflow to improve the structural strength of the bottom of the battery module, and the second overflow channel 2142 is mainly used for smooth venting.

[0062] When the thermally conductive adhesive 5 is applied in the form of an adhesive strip, the adhesive strip is located between two adjacent first overflow channels 2141, and the width of the adhesive strip along the second direction is smaller than the distance between the two adjacent first overflow channels 2141, so that the adhesive strip is flattened and first bonded to the bottom of the end plate 21 before overflowing, so as to ensure the bonding strength.

[0063] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A battery module, characterized in that, include: A battery pack (1) includes a plurality of cells (11) arranged sequentially along a first direction; an end plate assembly (2) is disposed at both ends of the battery pack (1) in the first direction, the end plate assembly (2) includes an end plate (21) and a buffer layer (22), the buffer layer (22) is disposed on the side of the end plate (21) close to the battery pack (1), and the buffer layer (22) is fitted to the corresponding cell (11); the middle area of ​​the end plate (21) facing the buffer layer (22) is provided with a recess (211), and the middle area of ​​the buffer layer (22) facing the end plate (21) is provided with a protrusion (221), the recess (211) and the protrusion (221) are correspondingly adapted to each other.

2. The battery module according to claim 1, characterized in that: The recess (211) includes a first arcuate groove (2111) disposed along a second direction in the middle region of the end plate (21) facing the buffer layer (22), and the protrusion (221) includes a first arcuate protrusion (2211) disposed along a second direction in the middle region of the buffer layer (22) facing the end plate (21); and / or, the recess (211) includes a second arcuate groove (2112) disposed along a third direction in the middle region of the end plate (21) facing the buffer layer (22), and the protrusion (221) includes a second arcuate protrusion (2212) disposed along a third direction in the middle region of the buffer layer (22) facing the end plate (21); the first direction, the second direction and the third direction are perpendicular to each other, and the first direction and the second direction are parallel to the mounting plane of the battery module.

3. The battery module according to claim 2, characterized in that: The end plate (21) includes an end plate body (212) and the recess (211). The recess (211) is recessed away from the buffer layer (22) relative to the end plate body (212), and the end plate body (212) is located on the periphery of the recess (211). The buffer layer (22) includes a buffer body (222) and the protrusion (221). The protrusion (221) is protruding closer to the end plate (21) relative to the buffer body (222), and the buffer body (222) is located on the periphery of the protrusion (221). The recess (211) and the protrusion (221), and the end plate body (212) and the buffer body (222) are all provided in a concave-convex fit.

4. The battery module according to claim 3, characterized in that: The thickness D1 of one end of the end plate body (212) in the third direction along the first direction is 1~10mm, the thickness D2≤D1 of the other end of the end plate (21) in the third direction along the first direction, the thickness D3≥0.5mm of the concave part (211) along the first direction, and both D1 and D2 are greater than D3; the thickness d1 of both ends of the buffer body (222) in the third direction along the first direction is 1~10mm, the thickness d2 of the convex part (221) along the first direction, and D1+d1=D3+d2.

5. The battery module according to claim 2, characterized in that: At least one end of the end plate (21) in the third direction is provided with a chamfer structure, and the chamfer structure is provided on the side of the end plate (21) away from the buffer layer (22).

6. The battery module according to claim 1 or 2, characterized in that: The multiple cells (11) of the battery pack (1) are connected in series and / or in parallel via multiple electrical connectors (31). The multiple electrical connectors (31) are located on one side of the battery pack (1) in a third direction, and the multiple electrical connectors (31) are distributed at both ends of the battery pack (1) in a second direction. In the second direction, the electrical connectors (31) are spaced apart from the corresponding ends of the protrusion (221).

7. The battery module according to claim 1 or 2, characterized in that: The thickness of the protrusion (221) at any position along the first direction gradually increases as the distance between it and the edge of the protrusion (221) increases, and the gradual change process satisfies any one of the following function curves: linear function, quadratic function, tangent function, or piecewise function.

8. A battery pack, characterized in that, include: The housing (4) has an installation cavity (41) inside, and the two ends of the installation cavity (41) in the first direction are provided with support beams (42); the battery module according to any one of claims 1-7, wherein the battery pack (1) is installed in the matching installation cavity (41), and the end plate (21) is connected to the support beam (42) on the side away from the battery pack (1), and the other side of the battery module in the third direction is fixed to the housing (4) by thermally conductive adhesive (5).

9. The battery pack according to claim 8, characterized in that: An overflow channel (214) is provided on one side of the end plate (21) near the support beam (42). The overflow channel (214) is provided at the other end of the end plate (21) in a third direction and is connected to the thermally conductive adhesive (5). The overflow channel (214) extends along the second direction and / or the third direction.

10. The battery pack according to claim 9, characterized in that: The adhesive overflow channel (214) includes a first adhesive overflow channel (2141) extending in a third direction and a second adhesive overflow channel (2142) extending in a second direction. The first adhesive overflow channel (2141) is provided at intervals along the second direction. One end of each of the first adhesive overflow channels (2141) is connected to the thermally conductive adhesive (5), and the other end of each of the first adhesive overflow channels (2141) is connected to the second adhesive overflow channel (2142). One end of the first adhesive overflow channel (2141) is flared near the thermally conductive adhesive (5).

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