Connecting bar, battery module, and battery pack

Abstract

Provided in the present application are a connecting bar, a battery module, and a battery pack. The connecting bar comprises a main body portion and at least one welding portion, the thickness of the welding portion being less than the thickness of the main body portion. The connecting bar can mitigate the technical problem of damage to plastic elements of batteries during laser welding.

Description

Connector bars, battery modules, and battery packs

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 15, 2023, with application number 202323444551.0. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a connecting bar, a battery module and a battery pack. Background Art

[0003] The square battery module includes multiple batteries connected in series. The connecting bars between the batteries are usually made of aluminum bars. In related technologies, the connecting bars are usually configured as sheets with uniform thickness. In order to improve the current carrying capacity of the connecting bars, the thickness of the connecting bars is usually increased. In addition, the connecting bars are welded to the battery poles by laser welding. In order to ensure that the laser has enough energy to penetrate the connecting bars and weld the connecting bars to the poles, high-energy lasers are usually used for welding. However, during the laser welding process, the high energy of the laser can cause damage to the plastic parts at the edge of the battery poles, thereby leading to the risk of battery insulation failure. SUMMARY OF THE INVENTION

[0004] The embodiments of the present application provide a connecting bar, a battery module, and a battery pack, which can improve the technical problem that the connecting bar may damage the plastic parts of the battery during the laser welding process.

[0005] In a first aspect, an embodiment of the present application provides a connecting bar for connecting batteries in series and / or in parallel, wherein the connecting bar includes a main body and at least one welding portion, wherein the thickness of the welding portion is smaller than the thickness of the main body.

[0006] In a second aspect, an embodiment of the present application provides a battery module, comprising a first battery and a second battery arranged adjacent to each other and the above-mentioned connecting bar, wherein the connecting bar connects the positive electrode column of the first battery and the negative electrode column of the second battery.

[0007] In a third aspect, an embodiment of the present application provides a battery pack, which includes the above-mentioned battery module. Beneficial effects

[0008] The beneficial effects of this application are:

[0009] (1) The present application provides a connecting bar. By setting the thickness of the welding portion of the connecting bar to be smaller than the thickness of the main body, the thickness of the welding portion is reduced. Therefore, in the process of welding the welding portion of the connecting bar to the battery pole, the laser energy required for the welding portion can be reduced, thereby effectively avoiding high-energy laser damage to the insulating plastic parts near the battery pole.

[0010] (2) The present application provides a battery module, which includes a first battery and a second battery arranged adjacent to each other and the above-mentioned connecting bar, wherein the connecting bar connects the positive electrode post of the first battery and the negative electrode post of the second battery. By setting the thickness of the welding portion of the connecting bar to be less than the thickness of the main body, the thickness of the welding portion is reduced. Therefore, in the process of welding the welding portion of the connecting bar to the battery post, the laser energy required for the welding portion can be reduced, thereby effectively avoiding damage to the insulating plastic parts near the battery post by high-energy laser.

[0011] (3) The present application provides a battery pack, which includes the above-mentioned battery module, and the battery module includes a first battery and a second battery arranged adjacent to each other and the above-mentioned connecting bar, wherein the connecting bar connects the positive electrode post of the first battery and the negative electrode post of the second battery. By setting the thickness of the welding portion of the connecting bar to be less than the thickness of the main body, the thickness of the welding portion is reduced. Therefore, in the process of welding the welding portion of the connecting bar to the battery post, the laser energy required for the welding portion can be reduced, thereby effectively avoiding damage to the insulating plastic parts near the battery post by the high-energy laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG1 is a perspective view of a connection bar provided in an embodiment of the present application;

[0013] FIG2 is a front view of a connecting bar provided in an embodiment of the present application;

[0014] FIG3 is a perspective view of a connection row provided by an embodiment of the present application;

[0015] FIG4 is a perspective view of a connecting row from another perspective provided by an embodiment of the present application;

[0016] FIG5 is a cross-sectional view of a connecting bar provided in accordance with an embodiment of the present application;

[0017] FIG6 is an enlarged view of a portion A of FIG5 ;

[0018] FIG7 is an enlarged view of a portion B of FIG5 ;

[0019] FIG8 is a perspective view of a copper-aluminum composite bar provided in another embodiment of the present application;

[0020] FIG9 is an exploded view of a copper-aluminum composite bar provided in yet another embodiment of the present application;

[0021] FIG10 is a perspective view of a copper busbar provided in another embodiment of the present application;

[0022] FIG11 is a front view of a copper busbar provided in another embodiment of the present application;

[0023] Figure Number:

[0024] 100, connecting row;

[0025] 10. Aluminum busbar; 11. Main body; 111. First main body; 112. Second main body; 113. Third main body; 12. Welding portion; 121. First welding portion; 122. Second welding portion; 131. First surface; 132. Second surface; 141. First arch bridge portion; 142. Second arch bridge portion; 143. Third arch bridge portion; 15. Bend portion; 151. First bend portion; 152. Second bend portion; 153. Third bend portion; 154. First portion; 155. Second portion; 161. First through hole; 162. Second through hole; 17. Notch;

[0026] 20. Copper busbar; 21. Base portion; 211. First base portion; 212. Second base portion; 22. Hollow portion; 221. First hollow portion; 222. Second hollow portion; 23. Fourth arch bridge portion. Modes for Carrying Out the Invention

[0027] An embodiment of the present application provides a battery module comprising a plurality of batteries arranged in a matrix. The batteries may be cylindrical or prismatic, and the batteries may be connected in series, parallel, or hybrid to meet the capacity requirements of the battery module.

[0028] Taking a square battery module as an example, multiple batteries arranged side by side in a first direction form a battery pack, and multiple battery packs arranged side by side in a second direction form a single-layer battery module. The battery module can be a single-layer battery module or a double-layer battery module. The battery packs arranged side by side in the first direction include multiple groups of adjacent first and second batteries.

[0029] Each battery includes an outer shell, a core assembly wound in the inner cavity of the outer shell, and a top cover assembly for covering the open end of the outer shell. The core assembly includes a positive electrode sheet, a negative electrode sheet, and a separator arranged between the positive electrode sheet and the negative electrode sheet. The top cover assembly includes a cover plate and a positive electrode column and a negative electrode column fixed on the cover plate at intervals. The top cover assembly also includes two insulating plastic parts fixed on the cover plate, the positive electrode column is fixed in one of the insulating plastic parts, and the negative electrode column is fixed in the other insulating plastic part.

[0030] The battery module also includes a connecting bar 100, through which the adjacent first battery and second battery are connected in series. One side of the connecting bar 100 is connected to the positive electrode of the first battery or the second battery, and the other side of the connecting bar 100 is connected to the negative electrode of the second battery or the first battery. Furthermore, the connecting bar 100 is fixed to the battery electrode by laser welding.

[0031] The connecting bar 100 can also be used to connect at least two batteries in parallel.

[0032] In the related art, the connecting bar 100 is usually configured as a sheet with uniform thickness. During the laser welding process, the high energy of the laser may cause damage to the insulating plastic parts at the edge of the battery pole, thereby causing the risk of insulation failure of the battery.

[0033] The connecting bar 100 for connecting prismatic batteries in series typically uses an aluminum bar 10. The aluminum bar 10 needs to meet current-carrying capacity requirements, which are related to its design dimensions. The length and width of the aluminum bar 10 are typically designed based on the battery specifications, so there are design limits to the length and width of the aluminum bar 10. Therefore, the current-carrying capacity requirement can only be met by increasing the thickness of the aluminum bar 10. To meet the current-carrying capacity requirement, the thickness of the aluminum bar 10 cannot be less than 1.5 mm. Furthermore, to avoid high energy generated by laser welding, the thickness of the aluminum bar 10 cannot exceed 1.5 mm.

[0034] In order to prevent the insulating plastic parts of the battery from being melted by the laser during the process of laser welding the connecting bar 100 to the battery pole, and also to meet the current carrying capacity requirements of the connecting bar 100, the structure of the connecting bar 100 is optimized in the embodiments of the present application. Specifically, with reference to Figures 1 to 6, the connecting bar 100 includes a main body 11 and at least one welding part 12, and the thickness d2 of the welding part 12 is less than the thickness d1 of the main body 11.

[0035] It should be noted that the thickness d1 of the main body 11 and the thickness d2 of the welding portion 12 are both set to extend along the thickness direction of the connecting bar 100 , wherein the thickness direction of the connecting bar 100 is set to be perpendicular to the flow direction of the connecting bar 100 .

[0036] The welding portion 12 of the connecting bar 100 is used to be welded to the battery's pole. Since the thickness d2 of the welding portion 12 is less than the thickness d1 of the main body 11, on the one hand, the laser welding process can use relatively less energy to weld the welding portion 12, thereby avoiding the use of high-energy laser to damage the insulating plastic parts of the battery; on the other hand, the thickness d2 of the welding portion 12 is less than the thickness d1 of the main body 11, so that the welding portion 12 will form a groove area relative to the main body 11, which facilitates the laser welding device to accurately weld the groove area where the welding portion 12 is located, thereby avoiding the laser from damaging the area outside the welding portion 12.

[0037] The thickness d1 of the main body 11 is greater than the thickness d2 of the welding portion 12 . By increasing the thickness d1 of the main body 11 , the flow capacity of the connecting bar 100 is improved, thereby meeting the flow capacity requirements of the connecting bar 100 .

[0038] Furthermore, the reduced thickness of the weld portion 12 relative to the main body 11 accounts for 10% to 40% of the thickness d1 of the main body 11. In one example, the reduced thickness of the weld portion 12 relative to the main body 11 accounts for 40% of the thickness d1 of the main body 11. For example, if the thickness d1 of the main body 11 is 2.5 mm, the thickness d2 of the weld portion 12 is 1.5 mm, and the reduced thickness of the main body 11 relative to the weld portion 12 is 1 mm. In other alternative examples, the reduced thickness of the weld portion 12 relative to the main body 11 accounts for 15%, 20%, 25%, 30%, 35%, or any value between any two of the aforementioned values, of the thickness d1 of the main body 11.

[0039] Furthermore, in some embodiments provided in the present application, the thickness d1 of the main body 11 is not less than 1.5 mm, and the thickness d2 of the welding portion 12 is less than 1.5 mm. For example, the thickness d1 of the main body 11 can be 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, and a value between any two of the above values. The thickness d2 of the welding portion 12 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, and a value between any two of the above values.

[0040] The connecting bar 100 is constructed as a sheet structure, and the connecting bar 100 includes a first surface 131 and a second surface 132 arranged opposite to each other. The welding portion 12 is configured to be recessed inward from the first surface 131 to form a groove. During the laser welding process, the second surface 132 of the welding portion 12 abuts against the positive electrode or negative electrode of the battery. One side of the groove area of ​​the welding portion 12 is used for laser irradiation, and the main body 11 abuts against the insulating plastic part of the battery. The laser irradiates the groove area. The laser energy penetrates the welding portion 12 to weld the portion where the second surface 132 of the welding portion 12 contacts the positive electrode or negative electrode of the battery, thereby preventing the laser from damaging the insulating plastic part.

[0041] In some embodiments, the connecting bar 100 further includes a thickening structure, the thickening structure is connected to the main body portion 11 , and the thickening structure and the welding portion 12 are at least partially staggered.

[0042] It should be noted that the sum of the thickness of the above-mentioned thickened structure and the thickness of the main body 11 is greater than the thickness of the main body 11, wherein the thickness of the thickened structure is also set to be the thickness extending along the thickness direction of the connecting row 100, and the thickness direction of the connecting row 100 is set perpendicular to the flow direction perpendicular to the connecting row 100.

[0043] By providing a thickened structure on the connecting bar 100 , the flow capacity of the connecting bar 100 can be further improved.

[0044] In one embodiment provided in the present application, with reference to Figures 3 to 7, the connecting bar 100 includes an aluminum bar 10, the aluminum bar 10 includes the main body 11 and the welding portion 12, the thickening structure is integrally formed with the main body 11, the thickening structure includes a bent portion 15 formed by at least partially bending the main body 11, or the thickening structure can also be a protruding structure provided on the main body 11, and the protruding structure is provided to increase the thickness of the main body 11, thereby increasing the flow capacity of the connecting bar 100.

[0045] Taking the thickened structure including the bent portion 15 formed by at least partial bending of the main body 11 as an example, as shown in Figures 5 and 7, the bent portion 15 includes a first portion 154 and a second portion 155 that overlap each other, and the thickness d3 of the bent portion 15 is equal to the sum of the thickness of the first portion 154 and the thickness of the second portion 155. Therefore, the thickness of the bent portion 15 is greater than the thickness of the non-bent portion of the main body 11, and the thickness of the bent portion 15 is equal to twice the thickness of the non-bent portion of the main body 11.

[0046] As shown in FIG4 , the connecting bar 100 is further provided with a notch 17 adjacent to the bent portion 15. The notch 17 is formed by bending the bent portion 15. The notch 17 is used to avoid the mounting structure of the first and second batteries or other battery structures. By partially bending the main body 11 to form the avoidance notch 17, the current capacity of the partially bent connecting bar 100 is substantially the same as that of the non-bent connecting bar 100. It can be understood that although the cross-sectional area of ​​the region where the bent portion 15 is located is reduced, the thickness of the region where the bent portion 15 is located is increased. The area left by the bending of the bent portion 15 forms the avoidance notch 17, thereby preventing the cross-sectional area of ​​the connecting bar 100 from being too large and interfering with other structural components on the battery.

[0047] As shown in Figures 1 and 2, the main body 11 includes a first main body 111 and a second main body 112, and the aluminum bar 10 also includes a first arch bridge portion 141, which is used to connect the first main body 111 and the second main body 112. One end of the first arch bridge portion 141 is connected to the first main body 111, and the other end of the first arch bridge portion 141 is connected to the second main body 112; the welding portion 12 includes a first welding portion 121 and a second welding portion 122, the first welding portion 121 is located on the first main body 111, and the first main body 111 is configured to be arranged around the first welding portion 121, the second welding portion 122 is located on the second main body 112, and the second main body 112 is configured to be arranged around the second welding portion 122.

[0048] The first main body 111 is connected to the first battery, the first welding part 121 is welded to the positive electrode column of the first battery, the second main body 112 is connected to the second battery, the second welding part 122 is welded to the negative electrode column of the second battery, and the first arch bridge part 141 is located between the first battery and the second battery, thereby effectively buffering the relative displacement between the first battery and the second battery caused by battery expansion or vehicle vibration.

[0049] A through-hole structure is further provided on the welding portion 12, which is used to position the battery pole. A first through-hole 161 is provided on the first welding portion 121, and a second through-hole 162 is provided on the second welding portion 122. The first through-hole 161 is aligned with the top blind hole of the positive pole of the first battery, and the visual system recognizes it to achieve the positioning of the connecting row. The second through-hole 162 is aligned with the top blind hole of the negative pole of the second battery, and the visual system recognizes it to achieve the positioning of the connecting row, preventing welding to areas other than the battery pole, which may cause weld explosion and cold welding in the welding area of ​​the connecting row.

[0050] As shown in Figure 3, the main body 11 also includes a third main body 113 located between the first main body 111 and the second main body 112, and the connecting row 100 includes a first arch bridge portion 141 and a second arch bridge portion 142. The first arch bridge portion 141 is used to connect the first main body 111 and the third main body 113, and the second arch bridge portion 142 is used to connect the third main body 113 and the second main body 112.

[0051] By adding an arch bridge structure, the deformation capacity of the connecting bar 100 is further improved, thereby effectively buffering the relative displacement between the first battery and the second battery caused by battery expansion or vehicle vibration.

[0052] With further reference to Figures 3 and 4 , the connecting row 100 includes a first bending portion 151 located on the first main body portion 111, a second bending portion 152 located on the second main body portion 112, and a third bending portion 153 located on the third main body portion 113, wherein the first bending portion 151 is arranged close to the first arch bridge portion 141, the second bending portion 152 is arranged close to the first arch bridge portion 141 or the second arch bridge portion 142, and the third bending portion 153 is arranged close to the second arch bridge portion 142.

[0053] The first bent portion 151 on the first main body portion 111 has a greater thickness than the area where the non-bent portion is located on the first main body portion 111, and the second bent portion 152 on the second main body portion 112 has a greater thickness than the area where the non-bent portion is located on the second main body portion 112. The third main body portion 113 is configured as a whole as a bent structure. By providing a bent structure on the connecting bar 100, while maintaining the current flow capacity of the connecting bar 100, it is also possible to avoid interference between the connecting bar 100 and other structural components of the battery. For example, the thickness of the non-bending portion of the first main body 111 of the connecting bar 100 is 2.0 mm, the thickness of the first welding portion 121 is 1.5 mm, and the thickness of the first bending portion is 4.0 mm. The thickness of the non-bending portion of the second main body 112 is 2.0 mm, the thickness of the second welding portion 122 is 1.5 mm, and the thickness of the second bending portion is 4.0 mm. The third main body 113 is configured as a third bending portion 153 as a whole, and the thickness of the third bending portion 153 is 4.0 mm, thereby effectively improving the flow capacity of the connecting bar 100.

[0054] 8 to 11 , in another embodiment provided in the present application, the thickened structure of the connecting bar 100 is separately provided from the main body 11 of the connecting bar 100 , and the thickened structure is stacked on the main body 11 .

[0055] Specifically, the connecting bar 100 includes a first metal bar and a second metal bar, wherein the first metal bar includes an aluminum bar 10 and the second metal bar includes a copper bar 20. The conductivity of copper is approximately 58.5×106 S / m, and the conductivity of aluminum is approximately 37.7×106 S / m. Since the conductivity of the copper bar 20 is greater than that of the aluminum bar 10, the current carrying capacity of the connecting bar 100 is effectively improved.

[0056] The copper busbar 20 includes a base portion 21 and a hollow portion 22 , and the orthographic projection of the welding portion 12 on the copper busbar 20 is located in the hollow portion 22 .

[0057] Furthermore, the aluminum bar 10 includes a first main body portion 111 , a second main body portion 112 and a third arch bridge portion 143 for connecting the first main body portion 111 and the second main body portion 112 . A first welding portion 121 is provided on the first main body portion 111 , and a second welding portion 122 is provided on the second main body portion 112 .

[0058] The copper busbar 20 includes a first base portion 211, a second base portion 212, and a fourth arch bridge portion 23 for connecting the first base portion 211 and the second base portion 212. A first hollow portion 221 is provided on the first base portion 211, and a second hollow portion 222 is provided on the second base portion 212. The orthographic projection of the first base portion 211 on the aluminum busbar 10 coincides with the first main portion 111, so that the first base portion 211 fits the first main portion 111, and the orthographic projection of the first hollow portion 221 on the aluminum busbar 10 coincides with the first welding portion 121. , so that the first hollow portion 221 is arranged correspondingly to the first welding portion 121, the orthographic projection of the second base portion 212 on the aluminum bar 10 coincides with the second main body portion 112, so that the second base portion 212 is fitted with the second main body portion 112, the orthographic projection of the second hollow portion 222 on the aluminum bar 10 coincides with the second welding portion 122, so that the second hollow portion 222 is arranged correspondingly to the second welding portion 122, and the orthographic projection of the fourth arch bridge portion 23 on the aluminum bar 10 coincides with the first arch bridge portion 141, so that the fourth arch bridge portion 23 is fitted with the third arch bridge portion 143.

[0059] In one example, the first welding portion 121 and the second welding portion 122 are both configured as grooves with a square cross-section, and correspondingly, the first hollow portion 221 and the second hollow portion 222 are both configured as square holes.

[0060] The thickness d1 of the main portion 11 of the aluminum busbar 10 is 2.0 mm, and the thickness d2 of the welding portion 12 of the aluminum busbar 10 is 1.5 mm. The thickness of the copper busbar 20 can be adaptively designed according to the required flow capacity of the connecting bar 100. When the connecting bar 100 requires a larger flow capacity, the thickness of the copper busbar 20 is increased. When the required flow capacity of the connecting bar 100 is smaller, the thickness of the copper busbar can be reduced accordingly.

[0061] An embodiment of the present application also provides a battery pack, which includes a case and multiple battery modules arranged inside the case. The multiple battery modules are arranged to be connected in series, parallel or mixed to meet the usage requirements of the battery pack. The battery pack is used in electrical equipment or the battery pack is used in power tools.

Claims

1. A connection bar (100) for connecting batteries in series and / or in parallel, the connection bar (100) comprising a main body (11) and at least one welding part (12), the thickness of the welding part (12) being smaller than the thickness of the main body (11).

2. The connecting bar (100) according to claim 1, wherein: The thickness of the welding portion (12) is reduced relative to the thickness of the main body (11) by 10% to 40% of the thickness of the main body (11); And / or, the thickness of the main body (11) is not less than 1.5 mm, and the thickness of the welding portion (12) is less than 1.5 mm.

3. The connecting row (100) according to any one of claims 1 to 2, further comprising a thickening structure, the total thickness of the thickening structure and the main body portion being greater than the thickness of the main body portion, the thickening structure being connected to the main body portion (11), and the thickening structure and the welding portion (12) being at least partially staggered.

4. The connecting bar (100) according to claim 3, wherein: The thickening structure is integrally arranged with the main body (11), and the thickening structure comprises a bent portion (15) formed by bending a portion of the main body (11); and / or the thickening structure comprises a protrusion on the main body (11).

5. The connecting bar (100) according to claim 4, wherein: The connection row (100) is further provided with a notch (17), the notch (17) being adjacent to the bending portion (15), and the notch (17) being configured to be formed by bending the bending portion (15).

6. The connecting bar (100) according to claim 4, wherein: The main body (11) comprises a first main body (111), a second main body (112), and a third main body (113) located between the first main body (111) and the second main body (112); the welding portion (12) comprises a first welding portion (121) and a second welding portion (122); the first welding portion (121) is located on the first main body (111), the second welding portion (122) is located on the second main body (112); a first arch bridge portion (141) is connected between the first main body (111) and the third main body (113); and / or a second arch bridge portion (142) is connected between the second main body (112) and the third main body (113).

7. The connecting bar (100) according to claim 6, wherein: The bending portion (15) comprises a first bending portion (151) located on the first main body portion (111), a second bending portion (152) located on the second main body portion (112), and a third bending portion (153) located on the third main body portion (113), wherein the first bending portion (151) is arranged close to the first arch bridge portion (141), the third bending portion (153) is arranged between the first arch bridge portion (141) and the second arch bridge portion (142), and the second bending portion (152) is arranged close to the second arch bridge portion (142).

8. The connecting bar (100) according to claim 3, wherein: The thickening structure is arranged separately from the main body (11), and the thickening structure is stacked on the main body (11).

9. The connecting bar (100) according to claim 8, wherein: The connecting bar (100) comprises a first metal bar and a second metal bar, the first metal bar comprises the main body portion (11) and the welding portion (12), the thickened structure comprises the second metal bar, the second metal bar is combined with the first metal bar, the second metal bar comprises a base portion (21) and a hollow portion (22), and the orthographic projection of the welding portion (12) on the second metal bar is located within the hollow portion (22).

10. The connecting bar (100) according to claim 9, wherein: The electrical conductivity of the second metal row is greater than the electrical conductivity of the first metal row.

11. The connecting bar (100) according to claim 10, wherein: The first metal bar is configured as an aluminum bar (10), and the second metal bar is configured as a copper bar (20).

12. The connecting bar (100) according to claim 9, wherein: The first metal row comprises a first main body portion (111), a second main body portion (112), and a third arch bridge portion (143) for connecting the first main body portion (111) and the second main body portion (112).

13. The connecting bar (100) according to claim 12, wherein: The second metal row comprises a first base portion (211), a second base portion (212), and a fourth arch bridge portion (23) for connecting the first base portion (211) and the second base portion (212); the first base portion (211) is in contact with the first main body portion (111), the fourth arch bridge portion (23) is in contact with the third arch bridge portion (143), and the second base portion (212) is in contact with the second main body portion (112).

14. The connecting bar (100) according to any one of claims 1-2, wherein: The main body (11) and the welding portion (12) are integrally arranged.

15. A battery module, comprising a first battery and a second battery arranged adjacent to each other and a connecting bar (100) according to any one of claims 1 to 14, wherein the connecting bar (100) connects the positive electrode column of the first battery and the negative electrode column of the second battery. 16 . A battery pack, comprising a box and a battery module arranged inside the box, wherein the battery module comprises the battery module according to claim 15 .

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