Battery module

Abstract

The application provides a battery module, which comprises a box assembly, a cell assembly and a busbar assembly. The box assembly comprises a box and a partition plate. The box comprises a containing cavity, an inlet and an outlet. The partition plate is arranged in the containing cavity and divides the containing cavity into a first cavity and a second cavity. The inlet is communicated with the first cavity, and the outlet is communicated with the second cavity. The partition plate is provided with an overflow hole communicated with the first cavity and the second cavity. The cell assembly is arranged in the containing cavity and comprises a plurality of cells. The cells pass through the partition plate, so that one end of the cell is located in the first cavity, and the other end of the cell is located in the second cavity. The busbar assembly is arranged in the first cavity and connected with one end of the cell located in the first cavity. When temperature adjusting medium is provided to the inlet to cool the cells, the temperature adjusting assembly can first cool the busbar and the area with higher cell temperature, and then cool the area with relatively lower cell temperature, which is beneficial to reduce the temperature difference of the cells and make the performance of the cells more stable.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery module. Background Technology

[0002] In related technologies, in order to improve the temperature regulation effect on the battery cells, the battery module will fill the battery box with a temperature regulating medium, so that the temperature regulating medium directly contacts the battery cells to quickly regulate the temperature of the battery cells.

[0003] However, during the charging and discharging process of the battery module, a large amount of heat is generated in the area where the battery cell is connected to the busbar. Even if the temperature of the battery cell is regulated by a temperature regulating medium, there is still a problem of uneven temperature distribution in the battery cell. Utility Model Content

[0004] The embodiments of this application provide a battery module that can improve the technical problem of uneven temperature distribution in the battery cells.

[0005] In a first aspect, embodiments of this application provide a battery module, comprising: A housing assembly includes a housing and a partition. The housing includes a receiving cavity, an inlet, and an outlet. The partition is disposed within the receiving cavity and divides the receiving cavity into a first cavity and a second cavity. The inlet communicates with the first cavity, and the outlet communicates with the second cavity. The partition is provided with a flow hole communicating between the first cavity and the second cavity. A battery cell assembly is disposed within the receiving cavity. The battery cell assembly includes a plurality of battery cells, which pass through the partition such that one end of the battery cell is located in the first cavity and the other end of the battery cell is located in the second cavity. A current-combining assembly is disposed in the first cavity, and the current-combining assembly is connected to one end of the battery cell located in the first cavity.

[0006] In some embodiments, a structural adhesive layer is provided on the side of the separator facing the first cavity, and the structural adhesive layer contacts the outer peripheral surface of the battery cell. Therefore, the structural adhesive layer can seal the gap between the separator and the battery cell, allowing the temperature regulating medium to remain in the first cavity for a longer period, resulting in better cooling of the busbar assembly and the portion of the battery cell located within the first cavity, which is beneficial for further reducing the temperature difference of the battery cell. Moreover, the high hardness of the structural adhesive layer provides better positioning for the battery cell, making its position more stable.

[0007] In some embodiments, the partition plate has a first protrusion protruding from the side facing the first cavity, the first protrusion passing through the structural adhesive layer, and the flow hole passing through the first protrusion. This facilitates the formation of the structural adhesive layer and prevents the adhesive from clogging the flow hole or leaking into the second cavity during the process of forming the structural adhesive layer by protruding the adhesive from the side of the partition plate facing the first cavity.

[0008] In some embodiments, the structural adhesive layer includes a side surface located on the side of the structural adhesive layer opposite to the partition; the first protrusion extends from the side surface to further reduce the risk of adhesive clogging the flow hole or leaking into the second cavity during the process of forming the structural adhesive layer by protruding adhesive towards the first cavity side of the partition.

[0009] In some embodiments, the height of the first protrusion extending beyond the side is greater than or equal to 3 mm, thereby reducing the risk of adhesive clogging the flow hole or leaking into the second cavity through the flow hole during the formation of the structural adhesive layer.

[0010] In some embodiments, the housing includes a cover plate, the first cavity is located between the cover plate and the structural adhesive layer, and a support post is provided on the side of the cover plate facing the first cavity, the support post being connected to the structural adhesive layer. The structural adhesive layer can support the cover plate through the support post, reducing the risk of cover plate deformation.

[0011] In some embodiments, the cover plate has a first flow channel communicating with the inlet, and the cover plate has a plurality of first connecting holes on the side facing the first cavity, connecting the first flow channel and the first cavity. This allows the temperature regulating medium to flow into different positions within the first cavity through the plurality of first connecting holes, which helps to improve the cooling uniformity of the temperature regulating medium on the multiple battery cells.

[0012] In some embodiments, the partition has a positioning hole for the battery cell to pass through, and the positioning hole is interference-fitted with the battery cell. This further improves the sealing effect between the partition and the battery cell, preventing the temperature regulating medium in the first cavity from leaking out between the partition and the battery cell.

[0013] In some embodiments, the separator includes a main body and a sealing portion connected to each other, the sealing portion forming the positioning hole, and the hardness of the sealing portion being less than that of the main body. Therefore, the sealing portion has a certain degree of flexibility, allowing for a tighter fit with the outer peripheral surface of the battery cell, which further improves the sealing effect between the battery cell and the separator.

[0014] In some embodiments, the body and the sealing part are injection molded together, thereby increasing the connection strength between the body and the sealing part and making the processing of the body and the sealing part more convenient.

[0015] In some embodiments, the housing includes a bottom, and the second cavity is located between the bottom and the partition; the bottom is provided with a second flow channel communicating with the outlet, and the side of the bottom facing the second cavity is provided with a plurality of second connecting holes communicating with the second flow channel and the second cavity. This allows the temperature regulating medium in the second cavity to flow out from the outlet through the plurality of second connecting holes at different locations, which is beneficial for improving the cooling uniformity of the temperature regulating medium on multiple battery cells.

[0016] In some embodiments, a second protrusion is provided on the bottom side facing the second cavity. The second protrusion is located in the gap between the plurality of battery cells, and the second connecting hole penetrates the second protrusion. This allows the temperature regulating medium in the second cavity to enter the second connecting hole from the end of the second protrusion away from the bottom, thereby increasing the contact time between the temperature regulating medium in the second cavity and the area of ​​the battery cell near the separator, which is beneficial for improving the temperature uniformity of the battery cell.

[0017] The beneficial effects of the embodiments of this application are as follows: The battery module provided in this application embodiment includes a housing cavity, an inlet, and an outlet in the housing assembly. The housing cavity is divided into a first cavity communicating with the inlet and a second cavity communicating with the outlet by a partition in the housing cavity. The first cavity is connected to the second cavity through the flow hole of the partition. The battery cell of the battery cell assembly passes through the partition, with one end of the battery cell located in the first cavity and connected to the busbar assembly in the first cavity, and the other end of the battery cell located in the second cavity.

[0018] Since the busbar assembly and the battery cell are located at a higher temperature at one end of the first cavity, when a temperature regulating medium is supplied to the inlet to cool the battery cell, the temperature regulating medium will first enter the first cavity to cool the busbar assembly and the part of the battery cell located in the first cavity. Then, the temperature regulating medium in the first cavity flows into the second cavity through the flow holes of the partition to cool the part of the battery cell located in the second cavity. That is, the temperature regulating assembly first cools the area of ​​the busbar and the battery cell with a higher temperature, and then cools the area of ​​the battery cell with a relatively lower temperature. This helps to reduce the temperature difference of the battery cell and make the performance of the battery cell more stable. Attached Figure Description

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

[0020] Figure 1 This is an exploded structural diagram of one embodiment of the battery module provided in this application. Figure 2 A top view of the internal structure of the battery module provided in an embodiment of this application; Figure 3 A top view of the battery module provided in the embodiments of this application; Figure 4 for Figure 3 A cross-sectional view along the AA direction; Figure 5 for Figure 4 Enlarged view of point A in the middle.

[0021] Explanation of reference numerals in the attached figures: 1-Battery module; 10-Box assembly; 11-Box; 110-Receiving cavity; 1101-First cavity; 1102-Second cavity; 111-Inlet; 112-Outlet; 113-Cover plate; 1131-Support column; 1132-First flow channel; 1133-First connecting hole; 114-Bottom; 1141-Second flow channel; 1142-Second protrusion; 1143-Second connecting hole; 12-Separator; 121-Main body; 122-Sealing part; 123-First protrusion; 124-Flow hole; 125-Positioning hole; 13-Structural adhesive layer; 131-Side; 20-Cell assembly; 21-Cell; 30-Bucket assembly. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0023] Figure 1 This is an exploded structural diagram of one embodiment of the battery module provided in this application. Figure 1 As shown, the battery module 1 includes a housing assembly 10, a cell assembly 20, and a busbar assembly 30. The housing assembly 10 includes a housing 11, which includes a receiving cavity 110. The cell assembly 20 is disposed in the receiving cavity 110 and includes a plurality of cells 21. The busbar assembly 30 is disposed in the receiving cavity 110 and is connected to one end of the cell 21.

[0024] The housing 11 also includes an inlet 111 and an outlet 112, which are connected to the receiving cavity 110 so that the temperature regulating medium can enter the receiving cavity 110 through the inlet 111 and come into contact with the surfaces of the battery cell 21 and the busbar assembly 30 in the receiving cavity 110, so that the temperature regulating medium can quickly exchange heat with the battery cell 21 and the busbar assembly 30 to quickly regulate the temperature of the battery cell 21 and the busbar assembly 30. After that, the temperature regulating medium in the receiving cavity 110 is discharged through the outlet 112.

[0025] It should be noted that the temperature regulating medium can cool the battery cell 21 and the busbar assembly 30, or it can heat the battery cell 21 and the busbar assembly 30, depending on the environment and operating state of the battery module 1. Furthermore, the temperature regulating medium can be coolant, cooling oil, refrigerant, etc., and there are no restrictions here.

[0026] During the charging and discharging process, the battery module 1 generates significant heat near the connection between the battery cell 21 and the busbar assembly 30, causing a rapid temperature rise and resulting in large temperature differences at different locations of the battery cell 21, which affects the performance of the battery cell 21. To improve the uniformity of cooling of the battery cell 21 by the temperature regulating medium and reduce the temperature difference of the battery cell 21, this application provides a battery module 1.

[0027] In some embodiments, such as Figures 2 to 4 As shown, the housing assembly 10 includes a housing 11 and a partition 12. The housing 11 includes a receiving cavity 110, an inlet 111, and an outlet 112. The partition 12 is disposed within the receiving cavity 110 and divides the receiving cavity 110 into a first cavity 1101 and a second cavity 1102. The inlet 111 communicates with the first cavity 1101, and the outlet 112 communicates with the second cavity 1102. The partition 12 has a flow hole 124 connecting the first cavity 1101 and the second cavity 1102. The battery cell assembly 20 is disposed within the receiving cavity 110 and includes a plurality of battery cells 21. The battery cells 21 pass through the partition 12 such that one end of the battery cell 21 is located in the first cavity 1101, and the other end of the battery cell 21 is located in the second cavity 1102. The busbar assembly 30 is disposed in the first cavity 1101 and is connected to the end of the battery cell 21 located in the first cavity 1101.

[0028] The battery module 1 provided in this application embodiment includes a housing 11 of the housing assembly 10 comprising a receiving cavity 110, an inlet 111, and an outlet 112. The receiving cavity 110 is divided into a first cavity 1101 communicating with the inlet 111 and a second cavity 1102 communicating with the outlet 112 by a partition 12 in the receiving cavity 110. The first cavity 1101 is connected to the second cavity 1102 through a flow hole 124 in the partition 12. The battery cell 21 of the cell assembly 20 passes through the partition 12, with one end of the battery cell 21 located in the first cavity 1101 and connected to the busbar assembly 30 in the first cavity 1101, and the other end of the battery cell 21 located in the second cavity 1102.

[0029] Since the busbar assembly 30 and the battery cell 21 are located at a relatively high temperature at one end of the first cavity 1101, when a temperature regulating medium is supplied to the inlet 111 to cool the battery cell 21, the temperature regulating medium will first enter the first cavity 1101 to cool the parts of the busbar assembly 30 and the battery cell 21 located in the first cavity 1101. Then, the temperature regulating medium in the first cavity 1101 flows into the second cavity 1102 through the flow hole 124 of the partition 12 to cool the part of the battery cell 21 located in the second cavity 1102. That is, the temperature regulating assembly first cools the area of ​​the busbar and the battery cell 21 with a higher temperature, and then cools the area of ​​the battery cell 21 with a relatively lower temperature. This helps to reduce the temperature difference of the battery cell 21 and make the performance of the battery cell 21 more stable.

[0030] It should be noted that all the cells 21 of the cell assembly 20 can pass through the partition 12, with one end of each cell 21 located in the first cavity 1101 and the other end located in the second cavity 1102. Alternatively, some of the cells 21 of the cell assembly 20 can pass through the partition 12, with one end of each cell 21 located in the first cavity 1101 and the other end located in the second cavity 1102.

[0031] In some embodiments, a structural adhesive layer 13 may be provided on the side of the partition 12 facing the first cavity 1101, and this structural adhesive layer 13 contacts the outer peripheral surface of the battery cell 21. Thus, the structural adhesive layer 13 can seal the gap between the partition 12 and the battery cell 21, allowing the temperature regulating medium to remain in the first cavity 1101 for a longer period, resulting in better cooling of the portion of the bus assembly 30 and the battery cell 21 located within the first cavity 1101, which is beneficial for further reducing the temperature difference of the battery cell 21. Moreover, the structural adhesive layer 13 has high hardness, providing better positioning for the battery cell 21 and making its position more stable.

[0032] In this process, adhesive can be applied to the side of the partition 12 facing the first cavity 1101. After the adhesive solidifies, a structural adhesive layer 13 is formed, which makes the formation of the structural adhesive layer 13 more convenient. Moreover, the structural adhesive layer 13 adheres more tightly to the battery cell 21, which is beneficial to improving the positioning effect of the battery cell 21 and the sealing effect of the gap between the battery cell 21 and the partition 12.

[0033] In some embodiments, such as Figure 4 and Figure 5 As shown, a first protrusion 123 can be provided on the side of the partition 12 facing the first cavity 1101. The first protrusion 123 passes through the structural adhesive layer 13, and the flow hole 124 of the partition 12 passes through the first protrusion 123. This makes the formation of the structural adhesive layer 13 more convenient and avoids the glue from clogging the flow hole 124 or leaking into the second cavity 1102 through the flow hole 124 during the process of forming the structural adhesive layer 13 by protruding the glue on the side of the partition 12 facing the first cavity 1101.

[0034] Among them, such as Figure 2 As shown, there are multiple first protrusions 123. Each of the multiple first protrusions 123 is provided with a flow hole 124 to allow the temperature regulating medium in the first cavity 1101 to flow more evenly into the second cavity 1102.

[0035] like Figure 4 and Figure 5 As shown, the structural adhesive layer 13 includes a side surface 131 located on the side of the structural adhesive layer 13 facing away from the partition 12. In some embodiments, a first protrusion 123 may extend beyond the side surface 131 to further reduce the risk of adhesive clogging the flow hole 124 or leaking into the second cavity 1102 through the flow hole 124 during the process of forming the structural adhesive layer 13 with adhesive protruding towards the first cavity 1101 from the partition 12.

[0036] Specifically, the height H of the first protrusion 123 extending from the side 131 can be greater than or equal to 3mm, thereby reducing the risk of adhesive clogging the flow hole 124 or leaking into the second cavity 1102 through the flow hole 124 during the formation of the structural adhesive layer 13. The height H of the first protrusion 123 extending from the side 131 can be 3.1mm, 3.3mm, 3.6mm, 4mm, etc.

[0037] like Figure 4 and Figure 5 As shown, the housing 11 includes a cover plate 113, and a first cavity 1101 is located between the cover plate 113 and the structural adhesive layer 13. A support post 1131 may be provided on the side of the cover plate 113 facing the first cavity 1101, and this support post 1131 is connected to the structural adhesive layer 13. Thus, the structural adhesive layer 13 can support the cover plate 113 through the support post 1131, reducing the risk of deformation of the cover plate 113.

[0038] One end of the support post 1131 is connected to the cover plate 113, and the other end is connected to the structural adhesive layer 13. Specifically, the other end of the support post 1131 is located inside the structural adhesive layer 13, thereby making the connection between the support post and the structural adhesive layer 13 more stable. There are multiple support posts 1131. The support post is located in the gap between the battery cells 21.

[0039] In some embodiments, a first flow channel 1132 communicating with the inlet 111 may be provided in the cover plate 113, and a plurality of first connecting holes 1133 communicating with the first flow channel 1132 and the first cavity 1101 may be provided on the side of the cover plate 113 facing the first cavity 1101. This allows the temperature regulating medium to flow into different positions of the first cavity 1101 through the plurality of first connecting holes 1133, which is beneficial to improving the cooling uniformity of the temperature regulating medium on the multiple battery cells 21.

[0040] Specifically, a first channel communicating with an inlet 111 can be provided inside the housing 11. One end of the first channel is connected to the inlet 111, and the other end extends to a cover plate 113 and communicates with a first flow channel 1132 within the cover plate 113. The inlet 111 is located on the side wall of the housing 11. The first channel is located on the side wall of the housing 11 and extends to the cover plate 113, communicating with the first flow channel 1132 within the cover plate 113.

[0041] Multiple first flow channels 1132 are arranged side by side inside the cover plate 113. The distribution direction of the multiple first flow channels 1132 forms an angle with the length direction of the first flow channels 1132. Multiple first connecting holes 1133 communicating with the first flow channels 1132 are arranged along the length direction of the first flow channels 1132.

[0042] In some embodiments, such as Figure 4 and Figure 5 As shown, the partition 12 has a positioning hole 125 through which the power supply core 21 passes, and the positioning hole 125 is interference-fitted with the power supply core 21. This can further improve the sealing effect between the partition 12 and the power supply core 21, and prevent the temperature regulating medium in the first cavity 1101 from leaking out between the partition 12 and the power supply core 21.

[0043] The separator 12 may include a main body 121 and a sealing part 122 connected to each other. The sealing part 122 forms a positioning hole 125, and the hardness of the sealing part 122 is less than that of the main body 121. As a result, the sealing part 122 has a certain degree of flexibility and fits more tightly with the outer peripheral surface of the battery cell 21, which is beneficial to further improve the sealing effect between the battery cell 21 and the separator 12.

[0044] In this way, the main body 121 and the sealing part 122 can be injection molded together, thereby increasing the connection strength between the main body 121 and the sealing part 122 and making the processing of the main body 121 and the sealing part 122 more convenient.

[0045] Specifically, the body of the partition 12 can be made of polycarbonate (PC), acrylonitrile butadiene styrene (ABS), or other similar materials. The sealing part 122 can be made of thermoplastic elastomer (TPE). The width of the sealing part 122 in the radial direction of the positioning hole 125 is greater than or equal to 1 mm to ensure a good sealing effect. The thickness of the sealing part 122 is the same as the thickness of the body.

[0046] like Figure 4 and Figure 5 As shown, the housing 11 includes a bottom 114, and a second cavity 1102 is located between the bottom 114 and the partition 12. A second flow channel 1141 communicating with the outlet 112 may be provided in the bottom 114, and multiple second connecting holes 1143 communicating with the second flow channel 1141 and the second cavity 1102 are provided on the side of the bottom 114 facing the second cavity 1102. This allows the temperature regulating medium in the second cavity 1102 to flow out from the outlet 112 through the multiple second connecting holes 1143 at different locations, which helps to improve the cooling uniformity of the temperature regulating medium on the multiple battery cells 21.

[0047] A second channel communicating with the outlet 112 can be provided inside the housing 11. One end of the second channel is connected to the outlet 112, and the other end extends to the bottom 114 and communicates with the second flow channel 1141 inside the bottom 114. Specifically, the outlet 112 is located on the side wall of the housing 11. The second channel is located on the side wall of the housing 11 and extends to the bottom 114, communicating with the second flow channel 1141 inside the bottom 114.

[0048] Multiple second flow channels 1141 are arranged side by side within the bottom 114. The distribution direction of the multiple second flow channels 1141 forms an angle with the length direction of the second flow channels 1141. Multiple second connecting holes 1143 communicating with the second flow channels 1141 are arranged along the length direction of the second flow channels 1141.

[0049] In some embodiments, a second protrusion 1142 may be provided on the side of the bottom 114 facing the second cavity 1102. The second protrusion 1142 is located in the gap between the plurality of battery cells 21, and the second connecting hole 1143 passes through the second protrusion 1142. As a result, the temperature regulating medium in the second cavity 1102 can enter the second connecting hole 1143 from the end of the second protrusion 1142 away from the bottom 114, thereby making the contact time between the temperature regulating medium in the second cavity 1102 and the area of ​​the battery cell 21 near the separator 12 longer, which is beneficial to improving the temperature uniformity of the battery cell 21.

[0050] The number of second protrusions 1142 can be multiple. Each of the multiple second protrusions 1142 is provided with a second connecting hole 1143.

[0051] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery module, characterized in that, include: A housing assembly includes a housing and a partition. The housing includes a receiving cavity, an inlet, and an outlet. The partition is disposed within the receiving cavity and divides the receiving cavity into a first cavity and a second cavity. The inlet communicates with the first cavity, and the outlet communicates with the second cavity. The partition is provided with a flow hole communicating between the first cavity and the second cavity. A battery cell assembly is disposed within the receiving cavity. The battery cell assembly includes a plurality of battery cells, which pass through the partition such that one end of the battery cell is located in the first cavity and the other end of the battery cell is located in the second cavity. A current-combining assembly is disposed in the first cavity, and the current-combining assembly is connected to one end of the battery cell located in the first cavity.

2. The battery module as described in claim 1, characterized in that, The partition plate has a structural adhesive layer on the side facing the first cavity, and the structural adhesive layer is in contact with the outer peripheral surface of the battery cell.

3. The battery module as described in claim 2, characterized in that, The partition plate has a first protrusion protruding on one side facing the first cavity, the first protrusion passing through the structural adhesive layer, and the flow hole passing through the first protrusion.

4. The battery module as described in claim 3, characterized in that, The structural adhesive layer includes a side surface located on the side of the structural adhesive layer opposite to the partition; the first protrusion extends out of the side surface.

5. The battery module as described in claim 4, characterized in that, The height of the first protrusion extending beyond the side is greater than or equal to 3 mm.

6. The battery module as described in claim 2, characterized in that, The enclosure includes a cover plate, the first cavity is located between the cover plate and the structural adhesive layer, and a support column is provided on the side of the cover plate facing the first cavity, the support column being connected to the structural adhesive layer.

7. The battery module as described in claim 6, characterized in that, The cover plate has a first flow channel communicating with the inlet, and the cover plate has a plurality of first connecting holes on the side facing the first cavity that connect the first flow channel and the first cavity.

8. The battery module as described in any one of claims 1 to 7, characterized in that, The partition plate has a positioning hole for the battery cell to pass through, and the positioning hole is interference-fitted with the battery cell.

9. The battery module as described in claim 8, characterized in that, The partition includes a main body and a sealing part that are connected to each other. The sealing part forms the positioning hole, and the hardness of the sealing part is less than the hardness of the main body.

10. The battery module as described in claim 9, characterized in that, The main body and the sealing part are injection molded together.

11. The battery module as described in any one of claims 1 to 7, characterized in that, The housing includes a bottom, and the second cavity is located between the bottom and the partition; the bottom is provided with a second flow channel communicating with the outlet, and the side of the bottom facing the second cavity is provided with a plurality of second connecting holes communicating with the second flow channel and the second cavity.

12. The battery module as described in claim 11, characterized in that, The bottom has a second protrusion protruding on the side facing the second cavity. The second protrusion is located in the gap between the plurality of battery cells, and the second connecting hole passes through the second protrusion.

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