Connecting bar, battery module and battery pack

Abstract

The utility model provides a connecting row, a battery module and a battery pack, the connecting row comprises a main body part and at least one welding part, the thickness of the welding part is smaller than that of the main body part, and the connecting row can solve the technical problem that plastic parts of batteries are damaged in the laser welding process.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a connecting bar, a battery module and a battery pack. Background Art

[0002] The square battery module includes a plurality of batteries connected in series. The connecting bars between the batteries are usually made of aluminum bars. In the related art, 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. Moreover, 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 to 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 causing the risk of battery insulation failure. Utility Model Content

[0003] The embodiments of the utility model 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.

[0004] In a first aspect, an embodiment of the utility model provides a connecting bar for connecting batteries in series and / or in parallel, wherein the connecting bar comprises a main body and at least one welding part, wherein the thickness of the welding part is smaller than the thickness of the main body.

[0005] In one embodiment, the thickness of the welding portion is reduced by 10% to 40% of the thickness of the main body portion relative to the thickness of the main body portion;

[0006] And / or, the thickness of the main body is not less than 1.5 mm, and the thickness of the welding part is less than 1.5 mm.

[0007] In one embodiment, a thickening structure is further included, wherein the thickening structure is connected to the main body, and the thickening structure and the welding portion are at least partially staggered.

[0008] In one embodiment, the thickening structure is integrally provided with the main body, and the thickening structure includes a bent portion formed by bending a portion of the main body; and / or the thickening structure includes a protrusion on the main body.

[0009] In one embodiment, the connection row is further provided with a notch, the notch is adjacent to the bending portion, and the notch is configured to be formed by bending the bending portion.

[0010] In one embodiment, the main body portion includes a first main body portion, a second main body portion and a third main body portion located between the first main body portion and the second main body portion, the welding portion includes a first welding portion and a second welding portion, the first welding portion is located on the first main body portion, the second welding portion is located on the second main body portion, a first arch bridge portion is connected between the first main body portion and the third main body portion; and / or a second arch bridge portion is connected between the second main body portion and the third main body portion.

[0011] In one embodiment, the bending portion includes a first bending portion located on the first main body portion, a second bending portion located on the second main body portion, and a third bending portion located on the third main body portion, wherein the first bending portion is arranged close to the first arch bridge portion, the third bending portion is arranged between the first arch bridge portion and the second arch bridge portion, and the second bending portion is arranged close to the second arch bridge portion.

[0012] In one embodiment, the thickening structure is separately provided with the main body portion, and the thickening structure is overlapped with the main body portion.

[0013] In one embodiment, the connecting row includes a first metal row and a second metal row, the first metal row includes the main body and the welding portion, the thickened structure includes the second metal row, the second metal row is combined on the first metal row, the second metal row includes a base portion and a hollow portion, and the orthographic projection of the welding portion on the second metal row is located in the hollow portion.

[0014] In one embodiment, the conductivity of the second metal row is greater than the conductivity of the first metal row.

[0015] In one embodiment, the first metal bar includes a first main body portion, a second main body portion, and a third arch bridge portion for connecting the first main body portion and the second main body portion.

[0016] In one embodiment, the second metal row includes a first base portion, a second base portion, and a fourth arch bridge portion for connecting the first base portion and the second base portion, the first base portion is in contact with the first main body portion, the fourth arch bridge portion is in contact with the third arch bridge portion, and the second base portion is in contact with the second main body portion.

[0017] In one embodiment, the main body portion and the welding portion are integrally provided.

[0018] In a second aspect, an embodiment of the utility model provides a battery module, which includes a first battery and a second battery arranged adjacent to each other and the above-mentioned connecting row, wherein the connecting row connects the positive electrode column of the first battery and the negative electrode column of the second battery.

[0019] In a third aspect, an embodiment of the present invention provides a battery pack, which includes the above-mentioned battery module.

[0020] Beneficial effects of the embodiments of the utility model:

[0021] In an embodiment of the utility model, the thickness of the welding portion of the connecting row is set to be smaller than the thickness of the main body, so that the thickness of the welding portion is thinned. Therefore, in the process of welding the welding portion of the connecting row to the pole of the battery, 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 pole of the battery.

[0022] The embodiments of the present invention also have the beneficial effects of:

[0023] In an embodiment of the utility model, by setting the thickness of the main body of the connecting row to be greater than the thickness of the welding portion, it is equivalent to thinning only the welding portion, thereby maintaining the thickness of the main body of the connecting row, thereby being able to maintain a higher current flow capacity of the connecting row as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 is a three-dimensional diagram of a connection row provided in an embodiment of the utility model;

[0026] Figure 2 It is a front view of a connecting bar provided by an embodiment of the utility model;

[0027] Figure 3 It is a three-dimensional diagram of a connection row from one viewing angle provided by an embodiment of the utility model;

[0028] Figure 4 is a three-dimensional diagram of a connection row from another perspective provided by an embodiment of the utility model;

[0029] Figure 5 is a cross-sectional view of a connecting bar provided by an embodiment of the utility model;

[0030] Figure 6 yes Figure 5 An enlarged view of the local A;

[0031] Figure 7 yes Figure 5 An enlarged view of the local B;

[0032] Figure 8 This is a three-dimensional diagram of a copper-aluminum composite bar provided by another embodiment of the utility model from one viewing angle;

[0033] Fig. 9 This is an exploded view of a copper-aluminum composite bar provided by another embodiment of the utility model;

[0034] Fig.10 is a three-dimensional diagram of a copper busbar provided in yet another embodiment of the utility model;

[0035] Fig.11 This is a front view of a copper busbar provided by another embodiment of the utility model;

[0036] Figure Number:

[0037] 100, connecting row;

[0038] 10. Aluminum bar; 11. Main body; 111. First main body; 112. Second main body; 113. Third main body; 12. Welding part; 121. First welding part; 122. Second welding part; 131. First surface; 132. Second surface; 141. First arch bridge part; 142. Second arch bridge part; 143. Third arch bridge part; 15. Bend part; 151. First bend part; 152. Second bend part; 153. Third bend part; 154. First part; 155. Second part; 161. First through hole; 162. Second through hole; 17. Notch;

[0039] 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; DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the utility model, and are not used to limit the utility model. In the utility model, unless otherwise stated, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0041] The embodiment of the utility model provides a battery module, which includes a plurality of batteries arranged in a matrix. The batteries can be cylindrical batteries or square batteries, and the plurality of batteries are arranged in series, parallel or mixed connection to meet the capacity requirements of the battery module.

[0042] Taking a square battery module as an example, multiple batteries are arranged side by side in a first direction to form a battery pack, and multiple battery packs are arranged side by side in a second direction to 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 adjacently arranged first batteries and second batteries.

[0043] Each battery includes an outer shell, a winding 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 winding 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, wherein 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.

[0044] The battery module also includes a connecting bar 100, through which the adjacent first battery and the second battery are connected in series, one side of the connecting bar 100 is connected to the positive electrode column of the first battery or the second battery, and the other side of the connecting bar 100 is connected to the negative electrode column of the second battery or the first battery. Furthermore, the connecting bar 100 is fixed to the battery column by laser welding.

[0045] The connecting bar 100 can also be used to connect at least two batteries in parallel.

[0046] In the related art, the connection 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.

[0047] The connection bar 100 for connecting square batteries in series usually adopts an aluminum bar 10. The aluminum bar 10 needs to meet the requirements of flow capacity, and the flow capacity of the aluminum bar 10 is related to its design size, wherein the length and width of the aluminum bar 10 are usually designed according to the specifications of the battery. Therefore, there are limits to the size design of the length and width of the aluminum bar 10. Therefore, the requirements of flow capacity can only be met by increasing the thickness of the aluminum bar 10. In order to meet the requirements of flow capacity, the thickness of the aluminum bar 10 cannot be less than 1.5 mm. In order to avoid high energy generated by laser welding, the thickness of the aluminum bar 10 cannot exceed 1.5 mm.

[0048] 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 requirements of the current carrying capacity of the connecting bar 100, the structure of the connecting bar 100 is optimized in the embodiment of the utility model. Figure 1 and Figure 2 As shown, the connection bar 100 includes a main body portion 11 and at least one welding portion 12 , and a thickness d2 of the welding portion 12 is smaller than a thickness d1 of the main body portion 11 .

[0049] The welding portion 12 of the connecting bar 100 is used for welding with the pole of the battery. 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 the welding portion 12 will form a groove area relative to the main body 11, which is convenient for 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.

[0050] 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 current carrying capacity of the connecting bar 100 is improved, thereby meeting the current carrying capacity requirement of the connecting bar 100 .

[0051] Further, the reduced thickness of the welding 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 welding portion 12 relative to the main body 11 accounts for 40% of the thickness d1 of the main body 11. For example, the thickness d1 of the main body 11 is 2.5 mm, the thickness d2 of the welding portion 12 is 1.5 mm, and the reduced thickness of the main body 11 relative to the welding portion 12 is 1 mm. In other optional examples, the reduced thickness of the welding portion 12 relative to the main body 11 accounts for 15%, 20%, 25%, 30%, 35% of the thickness d1 of the main body 11, and a value between any two of the above values.

[0052] Furthermore, in some embodiments provided by the present invention, 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.

[0053] 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 the negative electrode of the battery, and one side of the groove area of ​​the welding portion 12 is used for irradiating the laser, while the main body 11 abuts against the insulating plastic part of the battery. The laser irradiates the groove area, and the energy of the laser penetrates the welding portion 12 to weld the portion where the second surface 132 of the welding portion 12 contacts the positive electrode or the negative electrode of the battery, thereby avoiding damage to the insulating plastic part by the laser.

[0054] In some embodiments, the connection row 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.

[0055] By providing a thickened structure on the connecting bar 100 , the flow capacity of the connecting bar 100 can be further improved.

[0056] In one embodiment provided by the present utility model, reference Figures 3 to 7 As shown, the connecting bar 100 includes an aluminum bar 10, and the aluminum bar 10 includes the main body 11 and the welding portion 12. The thickened structure is integrally formed with the main body 11, and the thickened structure includes a bent portion 15 formed by at least partially bending the main body 11, or the thickened structure can also be a protruding structure provided on the main body 11. The protruding structure is provided to increase the thickness of the main body 11, thereby increasing the flow capacity of the connecting bar 100.

[0057] The thickened structure includes a bent portion 15 formed by at least a portion of the main body 11 being bent as an example. Figure 5 and Figure 7As shown, the bending portion 15 includes a first portion 154 and a second portion 155 overlapping each other, and a thickness d3 of the bending 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 bending portion 15 is greater than the thickness of the non-bending portion of the main body 11, and the thickness of the bending portion 15 is equal to twice the thickness of the non-bending portion of the main body 11.

[0058] like Figure 4 As shown, the connection bar 100 is also provided with a notch 17, which is adjacent to the bending portion 15. The notch 17 is configured to be formed by bending the bending portion 15, and the notch 17 is used to avoid the mounting structure of the first battery and the second battery or other battery structures. By partially bending the main body 11 to form the avoidance notch 17, the current capacity of the partially bent connection bar 100 is basically the same as the current capacity of the non-bent connection bar 100. It can be understood that although the cross-sectional area of ​​the area where the bending portion 15 is located is reduced, the thickness of the area where the bending portion 15 is located is increased, and the area left after the bending portion 15 is bent forms the avoidance notch 17, thereby avoiding the cross-sectional area of ​​the connection bar 100 from being too large and interfering with other structural parts on the battery.

[0059] like Figure 1 and Figure 2 As shown, 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, 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.

[0060] 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.

[0061] A through hole structure is further provided on the welding portion 12, and the through hole is used for positioning with 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, so as to prevent welding to the area other than the battery pole, which may cause welding explosion and cold welding in the welding area of ​​the connecting row.

[0062] like Figure 3 As shown, the main body portion 11 also includes a third main body portion 113 located between the first main body portion 111 and the second main body portion 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 portion 111 and the third main body portion 113, and the second arch bridge portion 142 is used to connect the third main body portion 113 and the second main body portion 112.

[0063] 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.

[0064] Further references Figure 3 and Figure 4 As shown, 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.

[0065] The first bent portion 151 on the first main body portion 111 has a greater thickness than the area where the non-bending portion on the first main body portion 111 is located, the second bent portion 152 on the second main body portion 112 has a greater thickness than the area where the non-bending portion on the second main body portion 112 is located, and the third main body portion 113 is configured as a bent structure as a whole. By providing a bent structure on the connecting row 100, while maintaining the current flow capacity of the connecting row 100, interference between the connecting row 100 and other structural components of the battery can also be avoided. 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, 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, the thickness of the second bending portion is 4.0 mm, and 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 current flow capacity of the connecting bar 100.

[0066] refer to Figures 8 to 11 As shown, in another embodiment provided by the present invention, 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 .

[0067] 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 58.5×106S / m, and the conductivity of aluminum is approximately 37.7×106S / 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.

[0068] 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 .

[0069] 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 .

[0070] 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 body portion 111, so that the first base portion 211 fits the first main body 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.

[0071] 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.

[0072] Among them, the thickness d1 of the main body 11 of the aluminum bar 10 is 2.0 mm, the thickness d2 of the welding portion 12 of the aluminum bar 10 is 1.5 mm, and the thickness of the copper bar 20 can be adaptively designed according to the flow capacity required by the connecting bar 100. When the connecting bar 100 requires a larger flow capacity, the thickness of the copper bar 20 is increased, and when the flow capacity required by the connecting bar 100 is smaller, the thickness of the copper bar can be reduced accordingly.

[0073] An embodiment of the utility model also provides a battery pack, which includes a box body and a plurality of battery modules arranged inside the box body. The plurality of battery modules are arranged to be connected in series, in parallel or in mixed connection to meet the usage requirements of the battery pack. The battery pack is used in electrical equipment or in power tools.

[0074] The above is a detailed introduction to the embodiments of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for technicians in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A connecting bar for connecting batteries in series and / or in parallel, characterized in that: The connecting row includes a main body and at least one welding portion, and the thickness of the welding portion is smaller than the thickness of the main body; The connection row further includes a thickening structure, the thickening structure is connected to the main body, and the thickening structure and the welding portion are at least partially staggered.

2. The connecting bar according to claim 1, characterized in that: The thickness of the welding part is reduced by 10% to 40% of the thickness of the main body part; And / or, the thickness of the main body is not less than 1.5 mm, and the thickness of the welding part is less than 1.5 mm.

3. The connecting bar according to claim 1, characterized in that: The thickened structure is integrally arranged with the main body, and the thickened structure includes a bent portion formed by bending a portion of the main body; and / or the thickened structure includes a protrusion on the main body.

4. The connecting bar according to claim 3, characterized in that: The connection row is further provided with a notch, the notch is adjacent to the bending portion, and the notch is configured to be formed by bending the bending portion.

5. The connecting bar according to claim 3, characterized in that: The main body portion includes a first main body portion, a second main body portion and a third main body portion located between the first main body portion and the second main body portion, the welding portion includes a first welding portion and a second welding portion, the first welding portion is located on the first main body portion, the second welding portion is located on the second main body portion, a first arch bridge portion is connected between the first main body portion and the third main body portion; and / or a second arch bridge portion is connected between the second main body portion and the third main body portion.

6. The connecting bar according to claim 5, characterized in that: The bending portion includes a first bending portion located on the first main body portion, a second bending portion located on the second main body portion, and a third bending portion located on the third main body portion, wherein the first bending portion is arranged close to the first arch bridge portion, the third bending portion is arranged between the first arch bridge portion and the second arch bridge portion, and the second bending portion is arranged close to the second arch bridge portion.

7. The connection bar according to claim 1, characterized in that: The thickening structure is separately arranged with the main body, and the thickening structure is stacked on the main body.

8. The connecting bar according to claim 7, characterized in that: The connecting row includes a first metal row and a second metal row, the first metal row includes the main body and the welding portion, the thickened structure includes the second metal row, the second metal row is combined on the first metal row, the second metal row includes a base portion and a hollow portion, and the orthographic projection of the welding portion on the second metal row is located in the hollow portion.

9. The connecting bar according to claim 8, characterized in that: The electrical conductivity of the second metal row is greater than the electrical conductivity of the first metal row.

10. The connecting bar according to claim 8, characterized in that: The first metal bar includes a first main body portion, a second main body portion, and a third arch bridge portion for connecting the first main body portion and the second main body portion.

11. The connection bar according to claim 10, characterized in that: The second metal row includes a first base portion, a second base portion and a fourth arch bridge portion for connecting the first base portion and the second base portion, the first base portion is fitted with the first main body portion, the fourth arch bridge portion is fitted with the third arch bridge portion, and the second base portion is fitted with the second main body portion.

12. The connecting bar according to any one of claims 1-2, characterized in that: The main body portion and the welding portion are integrally arranged.

13. A battery module, characterized in that: The battery module comprises a first battery and a second battery arranged adjacent to each other and a connecting bar according to any one of claims 1 to 12, wherein the connecting bar connects the positive electrode column of the first battery and the negative electrode column of the second battery.

14. A battery pack, characterized in that: The battery pack includes the battery module according to claim 13.

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