Busbar and battery pack

Abstract

The utility model provides a busbar and a battery pack, the busbar comprises two fixing parts and a connecting part, one side of each fixing part is used for welding a pole of a corresponding battery cell, the connecting part is connected between the end parts of the two fixing parts, and the other side of each fixing part is provided with an annular groove. Due to the fact that the annular groove is formed in the busbar, welding laser can be reflected for multiple times between the two opposite inner walls of the groove in the welding process, most laser energy can be absorbed by materials of the groove, the utilization rate of the welding laser energy is improved, and the welding efficiency is improved. And meanwhile, most welding slag generated in the welding process can be limited in the groove through the annular structure of the groove, and the influence of welding slag splashing on a battery product is reduced.

Description

Technical Field

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

[0002] In related technologies, to secure the busbar to the battery cell terminals, a circular groove is often milled on the busbar's upper surface, and the battery cell terminals are welded together within this groove. However, during the welding process, some of the laser light used for welding is reflected and wasted, resulting in low laser energy utilization. Furthermore, the welding process can produce slag spatter, which can pose a safety hazard to battery products. Utility Model Content

[0003] The embodiments of the present utility model provide a busbar and a battery pack, which can solve the problems of low welding laser energy utilization and welding slag splashing.

[0004] In a first aspect, an embodiment of the present invention provides a busbar, comprising:

[0005] Two fixing parts, one side of each fixing part is used for welding the corresponding battery cell pole; and

[0006] A connecting portion connected between ends of the two fixing portions;

[0007] Wherein, an annular groove is provided on the other side of the fixing portion.

[0008] In one embodiment, the angle between the bottom surface of the groove and the side surface of the groove is 30° to 90°.

[0009] In one embodiment, 2 mm ≤ T1 ≤ 5 mm, 1 mm ≤ D1 ≤ 2.5 mm, and D1 < T1; wherein T1 is the thickness of the fixing portion, and D1 is the depth of the groove.

[0010] In one embodiment, the busbar further includes a sealing member, which is located in the groove and abuts against an inner wall of the groove.

[0011] In one embodiment, 0.7 mm ≤ T2 ≤ D1-0.3 mm; wherein T2 is the thickness of the sealing member in the depth direction of the groove.

[0012] In one embodiment, T3≥T4+2 mm; wherein T3 is the width of the seal, and T4 is the width of the opening of the groove.

[0013] In one embodiment, 1.5 mm ≤ D2 ≤ 2.5 mm; wherein D2 is the distance between the bottom surface of the groove and the other side of the fixing portion.

[0014] In one embodiment, the width of the bottom surface of the groove is 2 mm to 4 mm.

[0015] In one embodiment, 3 mm ≤ R ≤ 29 mm; wherein R is the distance between the edge of the orthographic projection of the center line of the bottom surface of the groove on one side of the fixing portion and the edge of the orthographic projection of the pole on one side of the fixing portion.

[0016] In one embodiment, each fixing portion has a welding area on one side for welding the pole, and the orthographic projection of the groove on one side is located in the welding area.

[0017] In one embodiment, the sides of the two fixing portions used for welding the corresponding poles are oriented in the same direction and are both facing away from the groove.

[0018] In a second aspect, an embodiment of the present invention provides a battery pack comprising a plurality of bus bars as described in the first aspect.

[0019] The utility model provides a busbar and a battery pack. The busbar includes two fixing portions, one side of each fixing portion being used to weld a corresponding battery cell pole; and a connecting portion connected between the ends of the two fixing portions; wherein the other side of the fixing portion is provided with an annular groove. Because the busbar provided by the utility model is provided with an annular groove, during the welding process, the welding laser will be reflected multiple times between the two opposing inner walls of the groove, so that most of the laser energy will be absorbed by the material of the groove, thereby improving the utilization rate of the welding laser energy. At the same time, the annular structure of the groove can also confine most of the welding slag generated during the welding process within the groove, reducing the impact of welding slag splash on the battery product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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.

[0021] Figure 1 This is a schematic structural diagram of a busbar provided by an embodiment of the present utility model;

[0022] Figure 2 yes Figure 1 A top view of

[0023] Figure 3 yes Figure 2 sectional view of ;

[0024] Figure 4 This is a schematic diagram of the structure of a sealing member provided by an embodiment of the present utility model being fixed to a busbar;

[0025] Figure 5 yes Figure 4 It is a top view;

[0026] Figure 6 yes Figure 5 sectional view of ;

[0027] Figure 7 yes Figure 6 A magnified schematic diagram of part C;

[0028] Figure 8 It is a schematic diagram of the structure of the busbar connected to the battery cell;

[0029] Figure 9 yes Figure 8 Schematic diagram of the first and second orthographic projections of the lower surface of the middle busbar;

[0030] Description of reference numerals:

[0031] 100 , busbar; 101 , fixing portion; 102 , connecting portion; 110 , groove; 120 , sealing member; 200 , battery cell; 301 , first orthographic projection; 302 , second orthographic projection. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present utility model, unless otherwise specified, 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.

[0033] In related technologies, to secure the busbar to the battery cell terminals, a circular groove is often milled on the busbar's upper surface, and the battery cell terminals are welded together within this groove. However, during the welding process, some of the laser light used for welding is reflected and wasted, resulting in low laser energy utilization. Furthermore, the welding process can produce slag spatter, which can pose safety risks to battery products.

[0034] In order to solve the above-mentioned problems of low welding laser energy utilization and welding slag splashing, the embodiment of the present invention provides a busbar 100. Figure 1 , Figure 1This is a schematic structural diagram of a busbar 100 provided in an embodiment of the present invention. Figure 1 The busbar 100 is connected to the battery cell 200 (see Figure 8 ). The busbar 100 includes two fixing portions 101 and a connecting portion 102. One side of each fixing portion 101 is used for welding the corresponding battery cell 200 pole, and the connecting portion 102 is connected between the ends of the two fixing portions 101. The other side of the fixing portion 101 is provided with an annular groove 110.

[0035] The annular groove 110 structure on the busbar 100 provided in this embodiment can ensure that during the welding process of the busbar 100, the welding laser will undergo multiple reflections between the two opposing inner walls of the groove 110, so that most of the laser energy will be absorbed by the material of the groove 110, thereby improving the utilization rate of the welding laser energy. At the same time, the annular structure of the groove 110 also helps to confine most of the welding slag generated during the welding process within the groove 110, thereby reducing the impact of welding slag splash on the battery product. It should be noted that the shape of the groove 110 is not limited in this embodiment, that is, the shape of the groove 110 includes but is not limited to straight lines, rectangles, triangles, etc.

[0036] In order to further improve the utilization rate of laser energy, in some embodiments, the angle between the bottom surface of the groove 110 and the side surface of the groove 110 is 30° to 90°.

[0037] It is easy to understand that the welding laser enters the interior of the groove 110 from the opening of the groove 110. As the angle between the bottom surface of the groove 110 and the side surface of the groove 110 decreases, the number of reflections of the welding laser entering the groove 110 between the bottom surface of the groove 110 and the side surface of the groove 110 increases, thereby improving the energy utilization rate of the welding laser. Compared with the related art, the groove 110 structure provided in this embodiment can achieve a higher utilization rate of the laser power when using the same power welding laser for welding. Therefore, when using the busbar 100 provided in this embodiment, the power of the welding laser can be appropriately reduced to reduce the amount of welding slag generated during the welding process.

[0038] Among them, since the angle between the incident direction of the welding laser and the bottom surface of the groove 110 is usually not perpendicular, and after the groove 110 absorbs the laser energy, the groove 110 will absorb heat and melt, thereby causing the structure to usually change. Therefore, even when the angle between the bottom surface of the groove 110 and the side surface of the groove 110 is 90°, the welding laser is reflected many times between the bottom surface of the groove 110 and the side surface of the groove 110, which can still ensure a high utilization rate of the laser energy.

[0039] It is easy to understand that when the welding laser is shot into the groove 110 in a direction not perpendicular to the bottom surface of the groove 110, the number of reflections of the welding laser in the groove 110 will increase as the depth of the groove 110 increases. In order to further improve the utilization rate of the laser capacity, please refer to Figure 2 、 Figure 3 , Figure 2 yes Figure 1 A top view of Figure 3 yes Figure 2 In the cross-sectional view, in some embodiments, 2 mm ≤ T1 ≤ 5 mm, 1 mm ≤ D1 ≤ 2.5 mm, and D1 < T1, where T1 is the thickness of the fixing portion 101 and D1 is the depth of the groove 110.

[0040] Specifically, the thickness T1 of the fixing portion 101 is generally between 2 mm and 5 mm. The depth D1 of the groove 110 is limited to the range of 1 mm to 2.5 mm. Under this setting, the ratio between the depth D1 of the groove 110 and the thickness T1 of the fixing portion 101 is between 0.2 and 1.25. When the ratio of the two is within this range, it is possible to ensure that the depth of the groove 110 is deeper, which helps the welding laser to be reflected multiple times in the groove 110, so that the utilization rate of the laser energy is higher, thereby improving the welding effect. At the same time, the structure of the fixing portion 101 under this ratio range can also ensure that there is sufficient thickness between the bottom of the groove 110 and the side of the fixing portion 101 close to the pole of the battery cell 200, so that the structure after welding is stronger and less prone to damage. Therefore, the busbar 100 provided in this embodiment can ensure better laser energy utilization and structural stability during the welding process to ensure the high reliability of the battery product.

[0041] To further reduce the impact of welding slag on battery products, please refer to Figures 4 to 6 , Figure 4 This is a schematic diagram of the structure of the sealing member 120 provided in an embodiment of the present invention fixed to the busbar 100. Figure 5 yes Figure 4 It is a top view. Figure 6 yes Figure 5 In some embodiments, the busbar 100 further includes a sealing member 120 , which is located in the groove 110 and abuts against the inner wall of the groove 110 .

[0042] Specifically, after the busbar 100 is welded to the poles of the battery cell 200, the seal 120 is embedded in the groove 110, so that the seal 120 is fixed in the groove 110 and can seal the opening of the groove 110. The busbar 100 provided in this embodiment can ensure that welding slag in the groove 110 is retained in the groove 110 after falling off due to vibration during the movement of the busbar 100, thereby preventing the welding slag from flying out of the groove 110 and affecting other components.

[0043] To ensure the sealing between the seal 120 and the groove 110, please refer to Figure 7 , Figure 7 yes Figure 6 In the enlarged schematic diagram of part C, in some embodiments, T2≤D1-0.3 mm, where T2 is the thickness of the sealing ring in the depth direction of the groove 110.

[0044] Specifically, after the bus 100 is welded, a protrusion will exist in the groove 110 due to the material being melted by heat and then solidified by cooling. In this embodiment, the thickness T1 of the fixing portion 101 is limited to be less than the depth D1-0.3 mm of the groove 110, that is, in order to reserve a space of 0.3 mm in height in the groove 110 for the protrusion to occupy. At the same time, in order to ensure that the sealing between the seal 120 and the groove 110 is not insufficient due to the thickness of the seal 120, and usually the depth of the groove 110 is greater than 1 mm, the thickness of the seal 120 is limited to greater than 0.7 mm in this embodiment, which can ensure that the sealing between the seal 120 and the groove 110 meets the requirements.

[0045] Specifically, after the busbar 100 is welded, there will be a protrusion in the groove 110 where the material is melted by heat and then solidified by cooling. In order to deal with this situation, the present embodiment designs the thickness T1 of the fixing portion 101, which is limited to less than the depth D1 of the groove 110 minus 0.3 mm. The purpose of this setting is to leave enough height space for the protrusions that may appear in the groove 110 to ensure that the protrusions do not affect the installation of the seal 120. At the same time, in order to ensure effective sealing between the seal 120 and the groove 110, special consideration is given to the thickness of the seal 120. Normally, the depth of the groove 110 is greater than 1 mm, so the present embodiment limits the minimum thickness of the seal 120 to more than 0.7 mm. In this way, it can be ensured that the seal 120 has sufficient thickness and does not have insufficient sealing performance in the groove 110 due to being too thin. Through precise control of these design parameters, the protrusion in the groove 110 after welding can be effectively managed, while also ensuring good sealing between the seal 120 and the groove 110, thereby reducing the impact of welding slag located in the groove 110 flying out of the groove 110 on other components during the movement of the battery product.

[0046] To ensure the stability of the seal 120 in the groove 110, please refer to Figure 7 In some embodiments, T3 ≥ T4 + 2 mm, where T3 is the width of the seal 120 and T4 is the width of the opening of the groove 110 .

[0047] Specifically, in order to ensure that the seal 120 can be fixed in the groove 110, the seal 120 is usually made of a soft material with strong plasticity. In this embodiment, the width T3 of the seal 120 is limited to be greater than the width T4 of the opening of the groove 110 plus 2 mm. In the process of the seal 120 being embedded in the groove 110, the seal 120 will first be compressed until the width T3 of the seal 120 is less than the width T4 of the opening of the groove 110. Thereafter, the seal 120 will slowly expand until the width T3 of the seal 120 is equal to the width T4 of the opening of the groove 110. Since the seal 120 is made of a soft material, the two ends of the seal 120 close to the side of the groove 110 will cause an extrusion force on the side of the groove 110, thereby increasing the friction between the seal 120 and the side of the groove 110, thereby ensuring the stability of the seal 120 fixed in the groove 110.

[0048] To further ensure the sealing between the sealing member 120 and the groove 110 , in some embodiments, the side of the sealing member 120 away from the bottom surface of the groove 110 extends toward the side of the groove 110 to cover the groove 110 .

[0049] The seal 120 provided in this embodiment extends in the width direction of the seal 120 via a side away from the bottom of the groove 110 to form an extension portion, so that the width between the ends of the two extension portions of the seal 120 is greater than the width of the opening of the groove 110. This design ensures that the seal 120 can not only be fixed in the groove 110 to achieve effective sealing, but also that the upper extension portion can cover the opening of the groove 110, further strengthening the sealing between the seal 120 and the groove 110. Through this design of the seal 120, the seal 120 can fully cover the opening of the groove 110 after installation, which not only makes the installation of the seal 120 more stable and reliable, and is not easily loosened by the movement of the battery product, but also because the extension portions are located on both sides of the opening of the groove 110, the seal 120 can be easily replaced by controlling the extension portions.

[0050] Generally, the current carrying capacity of the busbar 100 increases with the thickness of the busbar 100, but the laser energy required for welding also increases with the thickness of the busbar 100. In order to ensure that the current carrying capacity of the busbar 100 meets the requirements while also ensuring that the laser energy required for welding is low, please refer to Figure 3 In some embodiments, 1.5 mm ≤ D2 ≤ 2.5 mm, where D2 is the distance between the bottom surface of the groove 110 and the other side of the fixing portion 101 , and the other side of the fixing portion 101 is the side close to the pole of the battery cell 200 .

[0051] Specifically, when the distance D2 between the bottom surface of the groove 110 and the other side of the fixing portion 101 is less than 1.5 mm, the current carrying capacity of the busbar 100 will be limited due to the excessively thin weld thickness. This will affect the electrical conductivity of the busbar 100. In particular, after the busbar 100 is electrically connected to the poles of the battery cell 200, the busbar 100 may not be able to effectively transmit current, thereby reducing the reliability of the battery product. On the other hand, if the distance D2 between the bottom surface of the groove 110 and the other side of the fixing portion 101 is greater than 2.5 mm, although the current carrying capacity of the busbar 100 is relatively strong in this case, the laser energy required for welding the busbar 100 to the poles of the battery cell 200 will also be significantly increased. High-energy laser welding not only increases production costs but also may cause potential thermal damage to other components of the battery assembly.

[0052] Therefore, to ensure that busbar 100 has sufficient current capacity while also controlling laser energy consumption during laser welding, this embodiment limits the distance between the bottom surface of groove 110 and the other side of fixing portion 101 to between 1.5 mm and 2.5 mm. Within this range, busbar 100 can stably transmit current while optimizing the energy required for laser welding, ensuring a balance between production efficiency and cost-effectiveness.

[0053] In some embodiments, the width of the bottom surface of the groove 110 is 2 mm to 4 mm.

[0054] Specifically, to ensure sufficient weld strength between the busbar 100 and the battery cell 200 posts while maintaining the busbar 100's flow area, this embodiment designs the bottom width of the groove 110 to be greater than or equal to 2 mm. However, if the bottom width of the groove 110 is too large, the number of reflections of the welding laser between the bottom and side surfaces of the groove 110 will be reduced, thereby reducing the utilization rate of the laser energy. Therefore, in this embodiment, the bottom width of the groove 110 is designed to be less than or equal to 4 mm. When the bottom width of the groove 110 is between 2 mm and 4 mm, it can ensure both good weld strength and flow area between the busbar 100 and the battery cell 200 posts, while also ensuring a high number of reflections of the welding laser between the bottom and side surfaces of the groove 110, resulting in higher laser energy utilization. This design of the busbar 100 structure considers the balance between weld strength, flow area, and laser utilization.

[0055] In some embodiments, please refer to Figure 8 、 Figure 9, 3mm≤R≤29mm, where R is the distance between the edge of the orthographic projection of the center line of the bottom surface of the groove 110 on one side of the fixing portion 101 and the edge of the orthographic projection of the pole of the battery cell 200 on one side of the fixing portion 101.

[0056] When welding the busbar 100 to the pole of the battery cell 200, the second orthographic projection 302 of the groove 110 on the side of the fixing portion 101 is located within the first orthographic projection 301 of the pole on the side of the fixing portion 101. When the area of ​​the first orthographic projection 301 is constant, the farther the edge of the second orthographic projection 302 is from the edge of the first orthographic projection 301, that is, the smaller the area of ​​the second orthographic projection 302, the smaller the perimeter of its edge. Since the perimeter of the edge of the second orthographic projection 302 also represents the perimeter of the welding surface of the busbar 100, when the edge of the second orthographic projection 302 is too far from the edge of the first orthographic projection 301, the perimeter of the welding surface of the busbar 100 will be too small, resulting in weak welding stability. In this embodiment, the distance between the edge of the second orthographic projection 302 and the edge of the first orthographic projection 301 is limited to between 3 mm and 29 mm. When the distance between the two is within this range, the structural stability of the busbar 100 and the poles of the battery cell 200 after welding is better, and the conductivity between the busbar 100 and the poles of the battery cell 200 is relatively stable.

[0057] It should be noted that the applicable scenario in this embodiment is that the first orthographic projection 301 is two concentric circles with different radii, and the second orthographic projection 302 is a circle with a radius greater than the two radii of the first orthographic projection 301 and concentric with the above two circles.

[0058] In some embodiments, one side of each fixing portion 101 of the busbar 100 has a welding area for welding to the corresponding battery cell 200 terminal, and the orthographic projection of the groove 110 on this side is located within the welding area. In this embodiment, by limiting the orthographic projection of the groove 110 on the side for welding the terminal to be located within the welding area, the area of ​​the groove used for welding remains within the welding area during the welding process, thereby ensuring the stability of the welded structure between the busbar 100 and the battery cell 200.

[0059] In some embodiments, the sides of the two fixing portions 101 of the busbar 100 used for welding the poles of the corresponding battery cells 200 face the same direction and are both away from the groove 110. In this embodiment, the sides of the two fixing portions 101 of the busbar 100 used for welding the poles face the same direction, that is, the two battery cells 200 electrically connected by the busbar 100 are on the same side of the busbar 100, thereby reducing the space occupied by the battery cells 200.

[0060] The present invention provides a busbar 100, which includes two connecting parts 102 and a connecting part 102, wherein one side of each fixing part 101 is used to weld the pole of the corresponding battery cell 200, and the connecting part 102 is connected between the ends of the two fixing parts 101. The other side of the fixing part 101 is provided with an annular groove 110, and the positive projection of the groove 110 on one side is located within the positive projection of the pole on one side. Since the busbar 100 provided by the present invention is provided with an annular groove 110, during the welding process, the welding laser will be reflected multiple times between the two opposite inner walls of the groove 110, so that most of the laser energy will be absorbed by the material of the groove 110, thereby improving the utilization rate of the welding laser energy. At the same time, the annular structure of the groove 110 can also limit most of the welding slag generated during the welding process to the groove 110, reducing the impact of welding slag splashing on the battery product.

[0061] The present invention also provides a battery pack according to an embodiment of the present invention. The battery pack includes battery cells 200 and the busbar 100 described above. A fixed portion of each busbar is electrically connected to a corresponding battery cell, and another fixed portion of each busbar is electrically connected to another adjacent battery cell. The orthographic projection of each groove on one side of the corresponding fixed portion is located within the orthographic projection of the pole of the corresponding battery cell on one side. In this embodiment, the orthographic projection of the groove on the side of the corresponding fixed portion close to the battery cell on the battery pack is located within the orthographic projection of the pole of the battery cell on one side. This ensures that the weld is always located in the welding zone during the welding process, thereby ensuring the stability of the structure after welding. The battery pack also has all the advantages of the busbar 100 described above, which will not be repeated here.

[0062] 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 those skilled in the art, based on the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A busbar, characterized in that: include: Two fixing parts, one side of each fixing part is used for welding the corresponding battery cell pole; as well as a connecting portion connected between the ends of the two fixing portions; Wherein, an annular groove is provided on the other side of the fixing portion.

2. The busbar according to claim 1, wherein: The angle between the bottom surface of the groove and the side surface of the groove is 30° to 90°.

3. The busbar according to claim 1 or 2, characterized in that: 2mm≤T1≤5mm, 1mm≤D1≤2.5mm, and D1<T1; wherein T1 is the thickness of the fixing portion, and D1 is the depth of the groove.

4. The busbar according to claim 3, characterized in that The invention also includes a sealing member, which is located in the groove and abuts against the inner wall of the groove.

5. The busbar according to claim 4, characterized in that 0.7mm≤T2≤D1-0.3mm; wherein T2 is the thickness of the sealing member in the depth direction of the groove.

6. The busbar according to claim 4, characterized in that T3≥T4+2mm; wherein, T3 is the width of the seal, and T4 is the width of the opening of the groove.

7. The busbar according to claim 3, characterized in that 1.5mm≤D2≤2.5mm; wherein D2 is the distance between the bottom surface of the groove and the other side of the fixing portion.

8. The busbar according to claim 1 or 2, characterized in that: The width of the bottom surface of the groove is 2 mm to 4 mm.

9. The busbar according to claim 1 or 2, characterized in that: 3mm≤R≤29mm; wherein R is the distance between the edge of the orthographic projection of the center line of the bottom surface of the groove on one side of the fixing portion and the edge of the orthographic projection of the pole on the said side of the fixing portion.

10. The busbar according to claim 1 or 2, characterized in that: One side of each fixing portion has a welding area for welding the pole, and the orthographic projection of the groove on the one side is located in the welding area.

11. The busbar according to claim 1 or 2, characterized in that: The sides of the two fixing portions for welding the corresponding poles are oriented in the same direction and both face away from the groove.

12. A battery pack, characterized in that: It comprises a plurality of battery cells and a busbar as described in any one of claims 1 to 11, wherein a fixing portion of each of the busbars is electrically connected to a corresponding battery cell, and another fixing portion of each of the busbars is electrically connected to another adjacent battery cell; wherein the orthographic projection of each of the grooves on the one side of the corresponding fixing portion is located within the orthographic projection of the pole of the corresponding battery cell on the one side.

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