Battery cell

Abstract

The utility model provides a battery cell which comprises a busbar and a pole piece, the pole piece comprises a main body and a pole lug, the pole lug is provided with a top surface and a bottom surface opposite to the top surface, the bottom surface is connected with the main body, and the top surface is far away from the main body; the tab is connected with the busbar and forms a welding mark, the edge of the welding mark is in a smoothly extending circle or oval shape, the distance between the position, closest to the bottom face, of the edge of the welding mark and the bottom face is D1, and D1 is larger than or equal to 10 mm. The welding marks connected between the busbar and the tabs on the pole pieces are arranged to be round or oval with the edges extending smoothly, so that the shearing force at the edges of the welding marks can be reduced, the stress directions of the edges are more uniformly dispersed in the welding process, the possibility that the edges of the welding marks are not prone to cracks and are damaged is reduced, and the service life of the welding marks is prolonged. In addition, the distance between the position, closest to the bottom face, on the welding printing edge and the bottom face is set to be larger than or equal to 10 mm, the possibility that the welding printing edge is torn can be further reduced, the product yield is improved, and the manufacturing cost is reduced.

Description

Technical Field

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

[0002] In current battery cells, the tabs and busbars are mostly connected together using ultrasonic welding technology. During welding, the welding head presses the tab foil onto the busbar surface, and under the high-frequency vibration of the ultrasonic waves, the tab and busbar are stably connected together in the soldering area. However, the foil at the edge of the soldering area is prone to damage and tearing, which reduces the yield of the tab-bus connection and increases manufacturing costs. Utility Model Content

[0003] The purpose of this application is to provide a battery cell with a high yield and reduced manufacturing cost.

[0004] This application provides a battery cell, including:

[0005] Busbar; and

[0006] An electrode includes a body and a tab. The tab has a top surface and a bottom surface opposite to the top surface. The bottom surface is connected to the body, and the top surface is away from the body. The tab is connected to the busbar and has a solder mark. The edge of the solder mark is a smoothly extending circle or ellipse, and the distance between the position closest to the bottom surface on the edge of the solder mark and the bottom surface is D1, where D1 ≥ 10 mm.

[0007] In one embodiment, the distance between the position closest to the top surface on the edge of the solder mark and the top surface is D2, where D2 ≥ 2 mm.

[0008] In one embodiment, the tab is provided with a slot that extends from the top surface to the bottom surface and penetrates both sides of the electrode sheet along the thickness direction to divide the tab into a first part and a second part, both of which have the solder mark formed thereon.

[0009] In one embodiment, the distance between the top surface and the bottom surface is set to D, and the distance from the position on the slot closest to the bottom surface to the bottom surface is D3, then D / 4 < D3 < D1.

[0010] In one embodiment, D1-D3 ≥ 2 mm.

[0011] In one embodiment, the slot has an inner bottom surface near the bottom surface, the inner bottom surface being a semi-circular arc surface.

[0012] In one embodiment, the slot has two inner sides extending from the top surface to the bottom surface, both inner sides being planar and parallel to each other, and the distance between the two inner sides being d1, where 1mm≤d1≤5mm.

[0013] In one embodiment, the inner side surface and the top surface are smoothly connected by a transition surface.

[0014] In one embodiment, the transition surface is an arc surface with a central angle of 90°.

[0015] In one embodiment, the solder mark includes a pre-soldering area and a final soldering area, the final soldering area is located within the range of the pre-soldering area and is concentrically arranged with the pre-soldering area, and the distance between the edge of the pre-soldering area and the edge of the final soldering area is d2, d2≥2mm.

[0016] The beneficial effects of the battery cell provided in this application embodiment are as follows: By setting the solder joint connecting the busbar and the electrode tab on the electrode plate to a circular or elliptical shape with a smooth, extending edge, the shear force at the edge of the solder joint can be reduced, making the force direction at the edge more evenly distributed during the welding process. This reduces the possibility of cracks and damage to the solder joint edge, thereby improving product yield and reducing manufacturing costs. Furthermore, by setting the distance between the position closest to the bottom surface on the solder joint edge and the bottom surface to be greater than or equal to 10mm, that is, setting the distance between the solder joint and the main body to be greater than or equal to 10mm, the possibility of the solder joint edge being torn can be further reduced, improving product yield and reducing manufacturing costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the connection structure between the busbar and the electrode in a battery cell provided in an embodiment of this application;

[0019] Figure 2 for Figure 1 A partially enlarged schematic diagram of the structure shown;

[0020] Figure 3 This is a schematic diagram of the busbar and electrode connection structure in a battery cell according to another embodiment;

[0021] The following are the labeling elements in the figure:

[0022] 100. Electrode; 110. Body; 111. Upper surface; 120. Tab; 121. Top surface; 122. Bottom surface; 123. Solder mark; 124. Pre-welding area; 125. Final welding area; 126. Groove; 127. Inner bottom surface; 128. Inner side surface; 129. Transition surface; 131. First part; 132. Second part; 133. Outer side surface; 134. Connecting surface; 200. Busbar. Detailed Implementation

[0023] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0024] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0025] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] Please refer to the following: Figures 1 to 3 The battery cells provided in the embodiments of this application will now be described.

[0028] The battery cell includes a busbar 200 and electrode plates 100. The electrode plate 100 includes a body 110 and a tab 120. The tab 120 has a top surface 121 and a bottom surface 122 opposite to the top surface 121. The bottom surface 122 is connected to the body 110, and the top surface 121 is away from the body 110. The tab 120 is connected to the busbar 200 and has a solder mark 123 formed thereon. The edge of the solder mark 123 is a smoothly extending circle (e.g., ...). Figure 1 , Figure 2 (as shown) or oval (as shown) Figure 3 As shown in the figure, the distance between the position closest to the bottom surface 122 on the edge of the solder mark 123 and the bottom surface 122 is D1, where D1 ≥ 10 mm.

[0029] Research has revealed that conventional solder marks 123 are rectangular. When the ultrasonic welding head presses the tab 120 foil onto the busbar 200, the edges of the foil in the pressure area wrinkle and lift. Under high-frequency ultrasonic vibration, the foil at the edge of the pressure area is prone to damage and tearing. In this application, by setting the solder mark 123 connecting the busbar 200 and the tab 120 on the electrode 100 to a circular or elliptical shape with smooth, extending edges, the shear force at the edge of the solder mark 123 can be reduced, making the force direction more evenly distributed. This reduces the possibility of cracks and damage at the edge of the solder mark 123, thereby improving product yield and reducing manufacturing costs.

[0030] Furthermore, research has revealed that because the thickness of the main body 110 in the electrode 100 is greater than the thickness of the tab 120, when the solder mark 123 is positioned close to the main body 110, the edge of the solder mark 123 is also prone to tearing due to pulling between it and the main body 110 under the action of the ultrasonic welding head. In this application, by setting the distance between the position closest to the bottom surface 122 on the edge of the solder mark 123 and the bottom surface 122 to be greater than or equal to 10 mm, that is, by setting the distance between the solder mark 123 and the main body 110 to be greater than or equal to 10 mm, the possibility of the edge of the solder mark 123 being torn can be further reduced, thereby improving product yield and reducing manufacturing costs.

[0031] In this application, the solder mark 123 includes a pre-soldering area 124 and a final soldering area 125. The final soldering area 125 is located within the range of the pre-soldering area 124 and is concentrically arranged with the pre-soldering area 124. The distance between the edge of the pre-soldering area 124 and the edge of the final soldering area 125 is d2, where d2 ≥ 2 mm.

[0032] It is understandable that for the formation of solder mark 123, a pre-soldering operation is required to form a pre-soldering area 124 on the tab 120, and then a final soldering operation is required to form a final soldering area 125 on the tab 120. The final soldering area 125 is located within the range of the pre-soldering area 124, so the edge of the pre-soldering area 124 constitutes the edge of solder mark 123.

[0033] During the formation of the pre-welding area 124, the ultrasonic welding head can press down on the tab 120 with a relatively small force, which can reduce the degree of wrinkling and deformation at the edge of the pre-welding area 124 and reduce the possibility of damage and tearing at the edge of the pre-welding area 124. During the formation of the final welding area 125, the ultrasonic welding head can further press down on the tab 120 within the pre-welding area 124. Due to the pre-connection effect of the outer pre-welding area 124, the degree of wrinkling and deformation at the edge of the final welding area 125 is also reduced, which further reduces the possibility of damage and tearing at the edge of the final welding area 125.

[0034] Furthermore, by making the distance between the edge of the pre-welding area 124 and the edge of the final welding area 125 greater than or equal to 2 mm, the area of ​​the outer pre-welding area 124 can be larger, thus providing a better pre-connection effect, reducing the degree of wrinkling and deformation of the edge of the final welding area 125, and reducing the possibility of damage and tearing of the edge of the final welding area 125.

[0035] In this application, the distance between the position closest to the top surface 121 on the edge of the weld mark 123 and the top surface 121 is D2, where D2 ≥ 2 mm. It is understood that when the distance between the position closest to the top surface 121 on the edge of the weld mark 123 and the top surface 121 is less than 2 mm, the top surface 121 is prone to warping during ultrasonic welding, causing damage and tearing of the edge of the weld mark 123. By maintaining a certain safe distance between the weld mark 123 and the top surface 121, the possibility of the weld mark 123 being damaged and torn can be reduced.

[0036] In this application, the tab 120 is provided with a slot 126, which extends from the top surface 121 to the bottom surface 122 and penetrates both sides of the electrode sheet 100 along the thickness direction to divide the tab 120 into a first part 131 and a second part 132. Both the first part 131 and the second part 132 are formed with solder marks 123.

[0037] It is understood that the slot 126 has a U-shaped inner wall surface, and the opening is located on the top surface 121. Thus, the two portions of the tab 120 located on both sides of the slot 126 are the first portion 131 and the second portion 132, respectively. The slot 126 can be located in the middle of the tab 120, so that the first portion 131 and the second portion 132 have equal areas. In other embodiments, the slot 126 may not be located in the middle of the tab 120, so that the first portion 131 and the second portion 132 have unequal areas.

[0038] By providing solder marks 123 in both the first part 131 and the second part 132, multiple connections can be formed between the entire tab 120 and the busbar, thereby improving the reliability of the connection between the two. Specifically, in this application, one solder mark 123 is provided in each of the first part 131 and the second part 132.

[0039] Furthermore, without the slot 126, if multiple solder marks 123 are provided on the tab 120, the solder marks 123 will be pulled against each other under the high-frequency action of the ultrasonic waves, resulting in damage and tearing at the edges of the solder marks 123. The presence of the slot 126 reduces the mutual interference between the solder marks 123 located in the first part 131 and the solder marks 123 located in the second part 132, thus reducing the possibility of damage and tearing at the edges of the solder marks 123.

[0040] In this application, the distance between the top surface 121 and the bottom surface 122 is set as D, and the distance from the position on the slot 126 closest to the bottom surface 122 to the bottom surface 122 is set as D3. Then, D / 4 < D3 < D1. It can be understood that the slot 126 needs to extend to a position closer to the bottom surface 122 than the edge of the solder mark 123, so that the solder mark 123 located in the first part 131 and the solder mark 123 located in the second part 132 will be completely isolated by the slot 126, thereby reducing the possibility of mutual interference between the two. Furthermore, the distance D between the top surface 121 and the bottom surface 122 is also the height dimension of the tab 120. By making the distance from the position closest to the bottom surface 122 on the slot 126 to the bottom surface 122 greater than D / 4, the height of the slot 126 in the direction from the top surface 121 to the bottom surface 122 is less than 3 / 4 of the height of the tab 120. This can avoid the problem that the height of the slot 126 is too large, which may easily lead to a decrease in the support strength of the first part 131 and the second part 132 and cause bending.

[0041] In this application, D1-D3≥2mm. It can be understood that the slot 126 extends towards the bottom surface 122 and needs to exceed the lower edge of the solder mark 123 (i.e., the position on the edge of the solder mark 123 closest to the bottom surface 122) by more than 2mm. In this way, the slot 126 can play a better role in segmentation and reduce the possibility of interference between the solder mark 123 located in the first part 131 and the solder mark 123 located in the second part 132.

[0042] In this application, the slot 126 has an inner bottom surface 127 near the bottom surface 122, and the inner bottom surface 127 is a semi-circular arc surface. It can be understood that the portion of the U-shaped inner wall of the slot 126 near the bottom surface 122 constitutes the inner bottom surface 127. By setting the inner bottom surface 127 as a semi-circular arc surface, the possibility of the electrode tab 120 being torn at the inner bottom surface 127 during ultrasonic welding can be reduced.

[0043] The slot 126 has two inner surfaces 128 extending from the top surface 121 to the bottom surface 122. Both inner surfaces 128 are planar and parallel, and the distance between them is d1, where 1mm ≤ d1 ≤ 5mm. It is understood that if the distance between the two inner surfaces 128 is too small, the first part 131 and the second part 132 will collide with each other under vibration during the formation of the solder mark 123, causing damage and tearing to the edge of the solder mark 123. If the distance between the two inner surfaces 128 is too large, with a fixed area of ​​the tab 120, the areas of the first part 131 and the second part 132 will become smaller, which is detrimental to the setting of the solder mark 123. By setting the distance between the two inner surfaces 128 to 1mm to 5mm, a larger area range for setting the solder mark 123 can be provided while avoiding collisions between the first part 131 and the second part 132.

[0044] Furthermore, the inner surface 128 and the top surface 121 are smoothly connected by a transition surface 129. It can be understood that the transition surface 129 makes the connection between the inner surface 128 and the top surface 121 more rounded, and makes the tab 120 more resilient to bending when subjected to impact.

[0045] Specifically, the transition surface 129 is an arc surface with a central angle of 90°. In this way, the transition surface 129 can be tangent to both the inner surface 128 and the top surface 121 to achieve the best smooth transition.

[0046] In this application, the surface of the main body 110 that connects to the bottom surface 122 is the upper surface 111, and the two side surfaces of the first part 131 and the second part 132 that are far apart from each other are the outer side surfaces 133. The outer side surfaces 133 and the upper surface 111 are smoothly connected by a connecting surface 134. The connecting surface 134 is an arc surface, and the connecting surface 134 extends from the outer side surfaces 133 to the upper surface 111 in a direction that gradually moves away from the groove 126. This arrangement can increase the structural strength of the connection between the tab 120 and the main body 110, and can also prevent the tab 120 and the upper surface 111 from being damaged or torn at the connection.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: Busbar; and An electrode includes a body and a tab. The tab has a top surface and a bottom surface opposite to the top surface. The bottom surface is connected to the body, and the top surface is away from the body. The tab is connected to the busbar and has a solder mark. The edge of the solder mark is a smoothly extending circle or ellipse, and the distance between the position closest to the bottom surface on the edge of the solder mark and the bottom surface is D1, where D1 ≥ 10 mm.

2. The battery cell according to claim 1, characterized in that, The distance between the position closest to the top surface on the edge of the solder mark and the top surface is D2, where D2 ≥ 2 mm.

3. The battery cell according to claim 1, characterized in that, The electrode tab has a slot that extends from the top surface to the bottom surface and penetrates both sides of the electrode sheet along the thickness direction to divide the electrode tab into a first part and a second part. Both the first part and the second part have the solder mark formed on them.

4. The battery cell according to claim 3, characterized in that, Let D be the distance between the top surface and the bottom surface, and let D3 be the distance from the position on the slot closest to the bottom surface to the bottom surface. Then D / 4 < D3 < D1.

5. The battery cell according to claim 4, characterized in that, D1-D3≥2mm.

6. The battery cell according to claim 3, characterized in that, The slot has an inner bottom surface near the bottom surface, and the inner bottom surface is a semi-circular arc surface.

7. The battery cell according to claim 3, characterized in that, The slot has two inner sides extending from the top surface to the bottom surface. Both inner sides are planar and parallel. The distance between the two inner sides is d1, where 1mm ≤ d1 ≤ 5mm.

8. The battery cell according to claim 7, characterized in that, The inner side surface and the top surface are smoothly connected by a transition surface.

9. The battery cell according to claim 8, characterized in that, The transition surface is a circular arc surface with a central angle of 90°.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The solder mark includes a pre-soldering area and a final soldering area. The final soldering area is located within the range of the pre-soldering area and is concentrically arranged with the pre-soldering area. The distance between the edge of the pre-soldering area and the edge of the final soldering area is d2, where d2 ≥ 2 mm.

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