Battery module and battery pack

Abstract

This utility model belongs to the field of battery technology and discloses a battery module and battery pack. The battery module includes battery cells, heat sinks, and a pre-tightening assembly, with multiple battery cells arranged sequentially at intervals. Each battery cell has heat sinks attached to two opposite sides in the arrangement direction. The pre-tightening assembly includes an elastic element and a limiting element. The elastic element is connected between the heat sinks on the sides of two adjacent battery cells with an initial pre-tightening force. The expansion of the battery cell causes the elastic element to undergo elastic deformation. The limiting element is used to stop the elastic deformation of the elastic element when it is in a preset deformation position. This battery module can suppress the high expansion problem of pouch cells, avoid abnormal cell deterioration caused by electrode fragmentation and cracking due to expansion, and effectively improve cycle life and safety.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery module and battery pack. Background Technology

[0002] Lithium-ion battery modules have advantages such as good performance, small size, and light weight. Among them, soft-pack lithium-ion power batteries are usually composed of soft-pack cells connected in series or in parallel to form power battery modules.

[0003] The outer packaging of pouch cells is a flexible aluminum-plastic film shell. The gap between the shell and the internal core is small. During charging and discharging, the expansion of the core is mainly reflected in changes in the cell thickness. These changes in thickness can adversely affect the lifespan of lithium-ion batteries and battery pack assembly. If the cell expansion is allowed to continue, it will greatly degrade the cell performance, shorten the battery pack life, cause a rapid decline in the battery pack's cycle capacity, and even lead to a drop in cycle capacity, ultimately resulting in safety issues.

[0004] Therefore, there is an urgent need for a battery module and battery pack to solve the above problems. Utility Model Content

[0005] The purpose of this utility model is to provide a battery module that can suppress the problem of high expansion of pouch cells, avoid abnormal cell deterioration caused by electrode fragmentation and cracking due to expansion, and effectively improve cycle life and safety of use.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] Battery module, including:

[0008] Battery cells, wherein multiple battery cells are arranged sequentially at intervals;

[0009] A heat sink is attached to two opposite sides of each of the battery cells in the arrangement direction;

[0010] The pre-tightening assembly includes an elastic element and a limiting element. The elastic element is connected between the heat sinks on the sides of two adjacent battery cells with an initial pre-tightening force. The expansion of the battery cells causes the elastic element to undergo elastic deformation. The limiting element is used to stop the elastic deformation of the elastic element when the elastic element is in a preset deformation position.

[0011] Optionally, the pretensioning assembly further includes a support rod through which multiple heat dissipation plates are sequentially passed, and the elastic element and the limiting element are both disposed on the support rod.

[0012] Optionally, a receiving groove is formed along the axial direction of the support rod, and the elastic element is movably disposed in the receiving groove;

[0013] The pre-tightening assembly also includes a connector. The side wall of the support rod is provided with an axial clearance groove that communicates with the receiving groove. The connector passes through the clearance groove and can slide along the length direction of the clearance groove. One end of the connector is connected to the elastic element and the other end is connected to the heat sink. When the battery cell expands, it can drive the connector and the heat sink to slide simultaneously along the length direction of the receiving groove.

[0014] Optionally, the limiting member protrudes from the inner wall of the receiving groove, and when the connecting member abuts against the limiting member, the elastic member is located at the preset deformation position.

[0015] Optionally, the elastic element is sleeved outside the support rod, and the two ends of the elastic element abut against the heat dissipation plates on the sides of two adjacent battery cells. The expansion of the battery cell causes the heat dissipation plates to press against the elastic element and produce elastic deformation.

[0016] Optionally, the limiting member protrudes from the outer wall of the support rod, and when the side wall of the heat sink abuts against the limiting member, the elastic member is located at the preset deformation position.

[0017] Optionally, multiple support rods are provided, and the multiple support rods are spaced apart on the periphery of the battery cell.

[0018] Optionally, the battery module further includes a foam layer sandwiched between the heat sinks on the sides of two adjacent battery cells.

[0019] Optionally, the heat sink is a solid panel; or, the heat sink is a perforated panel.

[0020] Another objective of this utility model is to provide a battery pack, including a housing and the aforementioned battery module, wherein the battery module is disposed within the accommodating space of the housing.

[0021] The beneficial effects of this utility model are:

[0022] The battery module provided by this utility model has heat sinks attached to two opposite sides of each cell in the arrangement direction. These heat sinks not only dissipate heat but also secure the cells. The pre-tightening assembly includes an elastic element and a limiting element. The elastic element is connected between the heat sinks on the sides of two adjacent cells with an initial pre-tightening force, ensuring a tight fit between the heat sink and the cell. When the cell expands during use, the heat sink on the cell's side moves outward, compressing the elastic element and causing it to elastically deform. In other words, the heat sink applies pressure to the elastic element under the expansion force of the cell, and the elastic element, in turn, recovers its elastic deformation, thus acting as a reaction force on the heat sink to suppress excessive cell expansion. When the elastic element reaches a preset deformation position, the limiting element stops the elastic deformation. Even if the cell continues to expand, the heat sink cannot further compress the elastic element, effectively controlling cell expansion. This battery module suppresses the problem of high expansion of pouch cells by setting up pre-tightening components, avoiding abnormal cell deterioration caused by electrode fragmentation and cracking due to expansion, and effectively improving cycle life and safety of use. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the battery module provided in Embodiment 1 of this utility model;

[0025] Figure 2 This is a schematic diagram of the heat sink and support rod provided in Embodiment 1 of this utility model;

[0026] Figure 3 This is a first cross-sectional view of the pre-tightening component provided in Embodiment 1 of this utility model;

[0027] Figure 4 This is a second cross-sectional view of the pre-tightening component provided in Embodiment 1 of this utility model.

[0028] In the picture:

[0029] 1. Battery cell;

[0030] 2. Heat sink;

[0031] 3. Pre-tightening assembly; 31. Support rod; 311. Receiving groove; 32. Elastic element; 33. Limiting element; 34. Connecting element;

[0032] 4. Foam layer;

[0033] 5. Fixing rod. Detailed Implementation

[0034] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this utility model, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this utility model, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0042] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0043] Example 1

[0044] This embodiment provides a battery module, such as Figure 1 As shown, the battery module includes a battery cell 1, a heat sink 2, and a pre-tightening assembly 3. In this embodiment, the battery cell 1 is a pouch cell. Pouch cells typically refer to lithium-ion cells with an aluminum-plastic composite film encapsulation. They have advantages such as light weight, low mold costs, and high safety, and are widely used in energy storage and new energy vehicles.

[0045] Specifically, the battery module includes multiple battery cells 1, which are arranged sequentially at intervals. Each battery cell 1 has a heat sink 2 attached to two opposite sides in the arrangement direction. The heat sink 2 not only serves to dissipate heat but also to fix the battery cells 1 in place.

[0046] More specifically, heat sink 2 is a solid panel. The thickness of heat sink 2 is 20um-500um, such as 50um, 100um, 150um, 200um, 250um, 300um, 350um, 400um, 450um, or 500um. Heat sink 2 can be made of aluminum or steel, and has good thermal conductivity.

[0047] Alternatively, in other embodiments, the heat sink 2 can also be a perforated panel to increase airflow rate and area, further improving heat dissipation. The perforations can be designed with different diameters and densities as needed, and are not limited here.

[0048] like Figures 1-4 As shown, the pre-tightening assembly 3 includes an elastic element 32 and a limiting element 33. The elastic element 32 is connected between the heat sink plates 2 on the sides of two adjacent battery cells 1 with an initial pre-tightening force. The elastic element 32 can apply an initial pre-tightening force to the heat sink plates 2 on both sides, ensuring that the heat sink plates 2 and the battery cells 1 are tightly fitted. In this embodiment, the elastic element 32 is a spring. The spring is installed in a compressed state so that the spring can apply an initial pre-tightening force to the heat sink plates 2 on both sides. The initial pre-tightening force is adjusted according to the required elastic force, specifically maintaining the initial surface pressure of the battery cell 1 at 0.01 MPa-0.3 MPa. This setting can ensure that the heat sink plates 2 play a preliminary role in fixing the battery cells 1.

[0049] When the battery cell 1 expands during use, the heat sink 2 on the side of the battery cell 1 moves outward, thereby compressing the elastic element 32 and causing it to elastically deform. In other words, the heat sink 2 applies pressure to the elastic element 32 under the expansion force of the battery cell 1, and the elastic element 32 needs to recover its elastic deformation, thus acting as a reaction force on the heat sink 2, pushing the heat sink 2 to suppress the excessive expansion of the battery cell 1. When the elastic element 32 reaches a preset deformation position, the limiting member 33 can stop the elastic deformation of the elastic element 32. This preset deformation position is the maximum travel position of the heat sink 2, and also the maximum value of the expansion deformation of the battery cell 1. At this time, the surface pressure between the heat sink 2 and the battery cell 1 is 0.1 MPa-0.3 MPa. Even if the battery cell 1 continues to expand, the heat sink 2 can no longer compress the elastic element 32; the elastic element 32 no longer compresses, the position of the heat sink 2 no longer moves, and the reverse restraining force on the battery cell 1 increases, thereby effectively preventing the expansion of the battery cell 1 and effectively improving cycle life and usage safety.

[0050] Continue to refer to Figures 1-4 In this embodiment, the pretensioning assembly 3 further includes a support rod 31, through which multiple heat dissipation plates 2 are sequentially inserted. Elastic members 32 and limiting members 33 are both disposed on the support rod 31. The support rod 31 can be made of steel, aluminum, or plastic; no specific material is required here.

[0051] Specifically, such as Figure 3 and Figure 4As shown, a receiving groove 311 is formed along the axial direction of the support rod 31, and the elastic member 32 is movably disposed within the receiving groove 311. The pre-tightening assembly 3 also includes a connecting member 34. The side wall of the support rod 31 has an axially formed clearance groove communicating with the receiving groove 311. The connecting member 34 passes through the clearance groove and can slide along the length direction of the clearance groove. One end of the connecting member 34 is connected to the elastic member 32, and the other end is connected to the heat sink 2. When the elastic member 32 undergoes elastic deformation, it can drive the connecting member 34 and the heat sink 2 to slide simultaneously along the length direction of the receiving groove 311. In this embodiment, the connecting member 34 can be a snap fastener, with one end of the snap fastener fixedly connected to a spring and the other end of the snap fastener fixedly connected to the heat sink 2. When the battery cell 1 expands, the side of the battery cell 1 pushes the heat sink 2 to move, thereby driving the connecting member 34 and the elastic member 32 to move, causing the elastic member 32 to be compressed and undergo elastic deformation.

[0052] More specifically, the limiting member 33 protrudes from the inner wall of the receiving groove 311. When the connecting member 34 abuts against the limiting member 33, the elastic member 32 is located at a preset deformation position. The limiting member 33 can be a protruding structure provided on the inner wall of the receiving groove 311. The distance between the limiting member 33 and the initial position of the heat sink 2 is the maximum stroke of the heat sink 2, which is also the maximum compression stroke of the elastic member 32. When the heat sink 2 moves under the push of the expansion force of the battery cell 1 until the connecting member 34 abuts against the limiting member 33, the heat sink 2 is fixed, thereby preventing further expansion of the battery cell 1.

[0053] Optionally, multiple support rods 31 are provided, and the multiple support rods 31 are spaced apart on the periphery of the battery cell 1. In this embodiment, four support rods 31 are provided, and the four support rods 31 are distributed in a rectangular array around the battery cell 1. This arrangement can make the force on the heat sink 2 uniform, thereby ensuring the uniformity of the reverse suppressive force when the battery cell 1 expands, thus ensuring the safety of the battery module during use.

[0054] Continue to refer to Figure 1 The battery module also includes a foam layer 4, which is sandwiched between the heat sink 2 on the sides of two adjacent battery cells 1. The foam layer 4 helps to fix the initial position of the battery cells 1. In addition, when the battery cells 1 expand, the foam layer 4 is compressed and provides a reverse restraining force, allowing the heat sink 2 to provide a more uniform force to limit the expansion of the battery cells 1. The thickness of the foam layer 4 is calculated based on half of the expansion thickness calculated according to the theoretical maximum expansion rate of the battery cells 1.

[0055] Preferably, one foam layer 4 is provided above and one below the height of the battery cell 1 to further improve the uniformity of the force on the heat sink 2.

[0056] Continue to refer to Figure 1The battery module also includes a fixing rod 5. In this embodiment, the fixing rod 5 is parallel to the height direction of the battery cell 1, located at both ends in the direction in which the battery cells 1 are arranged, and connects to the ends of the upper and lower support rods 31. The fixing rod 5 enables the battery module to be installed at the desired location.

[0057] This embodiment also provides a battery pack, which includes a housing and the aforementioned battery module, with the battery module disposed within the housing's accommodating space. The two ends of the fixing rod 5 are connected to the inner wall of the housing to secure the battery module within the housing.

[0058] Example 2

[0059] This embodiment provides a battery module that is basically the same as the battery module provided in Embodiment 1. The difference between this embodiment and Embodiment 1 lies in the specific structure of the pre-tightening component 3.

[0060] In this embodiment, the support rod 31 is a solid rod, and the elastic element 32 is sleeved on the outside of the support rod 31. The two ends of the elastic element 32 abut against the heat sink 2 on the sides of two adjacent battery cells 1. That is, the elastic element 32 is directly connected to the heat sink 2. When the battery cell 1 expands, the side of the battery cell 1 directly pushes the heat sink 2 to press against the elastic element 32, causing the elastic element 32 to undergo elastic deformation.

[0061] Meanwhile, the limiting member 33 protrudes from the outer wall of the support rod 31. When the side wall of the heat sink 2 abuts against the limiting member 33, the elastic member 32 is located at a preset deformation position. The limiting member 33 can be a protrusion structure provided on the outer wall of the support rod 31. The distance between the limiting member 33 and the initial position of the heat sink 2 is the maximum stroke of the heat sink 2, which is also the maximum compression stroke of the elastic member 32. When the heat sink 2 moves to abut against the limiting member 33 under the push of the expansion force of the battery cell 1, the heat sink 2 is fixed, thereby preventing further expansion of the battery cell 1.

[0062] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A battery module, characterized by, include: A battery cell (1), and a plurality of said battery cells (1) are arranged sequentially at intervals; Heat sink (2), each of the battery cells (1) has the heat sink (2) attached to both sides opposite to each other in the arrangement direction; The pre-tightening assembly (3) includes an elastic element (32) and a limiting element (33). The elastic element (32) is connected between the heat sinks (2) on the sides of two adjacent cells (1) with an initial pre-tightening force. The expansion of the cell (1) causes the elastic element (32) to undergo elastic deformation. The limiting element (33) is used to stop the elastic deformation of the elastic element (32) when the elastic element (32) is in a preset deformation position.

2. The battery module of claim 1, wherein, The pre-tightening assembly (3) also includes a support rod (31), through which multiple heat dissipation plates (2) are sequentially inserted, and the elastic element (32) and the limiting element (33) are both disposed on the support rod (31).

3. The battery module of claim 2, wherein, A receiving groove (311) is formed along the axial direction of the support rod (31), and the elastic element (32) is movably disposed in the receiving groove (311); The pre-tightening assembly (3) also includes a connector (34). The side wall of the support rod (31) is provided with an axial clearance groove that communicates with the receiving groove (311). The connector (34) passes through the clearance groove and can slide along the length direction of the clearance groove. One end of the connector (34) is connected to the elastic member (32), and the other end is connected to the heat sink (2). When the battery cell (1) expands, it can drive the connector (34) and the heat sink (2) to slide simultaneously along the length direction of the receiving groove (311).

4. The battery module of claim 3, wherein, The limiting member (33) protrudes from the inner wall of the receiving groove (311), and when the connecting member (34) abuts against the limiting member (33), the elastic member (32) is located at the preset deformation position.

5. The battery module according to claim 2, characterized in that, The elastic element (32) is sleeved on the outside of the support rod (31). The two ends of the elastic element (32) abut against the heat sink (2) on the side of the two adjacent battery cells (1). The expansion of the battery cell (1) causes the heat sink (2) to press against the elastic element (32) to produce elastic deformation.

6. The battery module of claim 5, wherein, The limiting member (33) protrudes from the outer wall of the support rod (31). When the side wall of the heat sink (2) abuts against the limiting member (33), the elastic member (32) is located at the preset deformation position.

7. The battery module of claim 2, wherein, Multiple support rods (31) are provided, and the multiple support rods (31) are spaced apart on the periphery of the battery cell (1).

8. The battery module of any one of claims 1-7, wherein, The battery module also includes a foam layer (4), which is sandwiched between the heat sinks (2) on the sides of two adjacent battery cells (1).

9. The battery module of any one of claims 1-7, wherein, The heat sink (2) is a solid panel; or, the heat sink (2) is a perforated panel.

10. A battery pack, characterized by, It includes a housing and a battery module as described in any one of claims 1-9, wherein the battery module is disposed within the receiving space of the housing.

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