Tab welding structure and lithium ion battery

Abstract

The utility model belongs to the technical field of batteries, and discloses a tab welding structure and a lithium ion battery, the tab welding structure comprises a pole piece and a tab, the pole piece comprises a current collector, and a first active material layer and a second active material layer which are arranged on two sides of the current collector in the thickness direction; a welding groove for placing a tab is formed in the edge of the first active material layer in the width direction, and the welding groove penetrates through the surface of the current collector in the thickness direction of the first active material layer. The tab comprises a connecting part and a welding part, the connecting part is connected with an external circuit, the welding part is arranged in the welding groove, the welding part is welded in the welding groove, and the welding part and the current collector are welded to form a welding printing area; the area of the welding printing area is set to be A, one side face, welded with the current collector, of the welding part is set to be a welding face, the area of the welding face is set to be S, and A is larger than 1 / 8S and smaller than 1 / 4S. According to the utility model, the welding strength and the stability of the tabs can be effectively ensured, and the use performance and the use reliability of the lithium ion battery are ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a tab welding structure and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries have high energy density, high average output voltage, low self-discharge, no memory effect, good cycle performance, and can achieve rapid charge and discharge. They also do not contain toxic substances and are known as green batteries, currently widely used in various electronic products and the electric vehicle industry. A lithium-ion battery consists of a positive electrode, a negative electrode, and a separator. Typically, a positive electrode tab is welded to the empty foil area on the surface of the positive electrode, and a negative electrode tab is welded to the empty foil area on the surface of the negative electrode. The positive and negative electrodes are then connected to an external circuit to enable the charging and discharging function of the lithium-ion battery.

[0003] Currently, electrode tabs are generally welded to the foil surface using ultrasonic welding equipment. Existing electrode tab welding technology is prone to problems such as low welding quality, easy detachment after welding, or easy welding of the foil during the welding process. These poor welding will reduce the performance and reliability of lithium batteries. Utility Model Content

[0004] The purpose of this invention is to provide a tab welding structure and a lithium battery that can effectively ensure the welding strength and stability of the tabs, and guarantee the performance and reliability of the lithium-ion battery.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] On the one hand, a tab welding structure is provided, including a tab and a electrode sheet. The electrode sheet includes a current collector and a first active material layer and a second active material layer disposed on both sides of the current collector in the thickness direction. The edge of the first active material layer is provided with a welding groove for placing the tab in the width direction. The welding groove extends through the thickness direction of the first active material layer to the surface of the current collector.

[0007] The electrode tab includes a connecting part and a welding part. The connecting part is connected to an external circuit, and the welding part is disposed in the welding groove. The welding part is welded to the current collector to form a solder mark area. The area of ​​the solder mark area is set as A. The side of the welding part that is welded to the current collector is set as the welding surface. The area of ​​the welding surface is set as S, where 1 / 8S < A < 1 / 4S.

[0008] In one embodiment, the length of the welded portion placed in the weld groove is set as H, and the length of the weld mark area along the length direction of the welded portion is set as h, where 1 / 3H < h < 1 / 2H.

[0009] In one embodiment, the width of the welded portion is set to D, and the width of the solder mark area along the width direction of the welded portion is set to d, where 1 / 3D < d < 1 / 2D.

[0010] In one embodiment, the width of the welded portion is smaller than the width of the weld groove, and the two sides of the welded portion in the width direction are respectively spaced apart from the first active material layer to form empty foil areas.

[0011] In one embodiment, the welding portion is disposed in the middle of the welding groove, and the empty foil areas on both sides of the welding portion are the same size.

[0012] In one embodiment, the solder mark area is centrally located within the soldering surface.

[0013] In one embodiment, the thickness of the tab is greater than the depth of the welding groove, and the edge of the first active material layer is provided with a clearance groove along the width direction. The clearance groove and the welding groove are arranged alternately along the length direction of the electrode sheet, and the positions of the clearance grooves of the two mating electrode sheets are corresponding to the positions of the tabs.

[0014] In one embodiment, the inner side of the clearance groove is provided with insulating tape.

[0015] In one embodiment, a protective gasket is provided on the side of the clearance groove facing the current collector, and when the two mating electrodes are mated, the protective gasket abuts against the electrode tab.

[0016] On the other hand, a lithium-ion battery is also provided, including the above-mentioned tab welding structure. The electrode includes a positive electrode and a negative electrode, and the tab includes a positive tab and a negative tab. The positive tab is welded to the positive electrode and the negative tab is welded to the negative electrode. When the positive electrode and the negative electrode are attached, the position of the positive tab corresponds to the position of the clearance groove on the negative electrode, and the position of the negative tab corresponds to the position of the clearance groove on the positive electrode.

[0017] The beneficial effects of this utility model are:

[0018] This utility model discloses a tab welding structure. A welding groove is provided for the tab to be inserted and welded to the current collector portion within the groove. The tab includes a welding portion disposed within the welding groove and a connecting portion disposed outside the groove for connection to an external circuit. Furthermore, the welding portion and the current collector form a weld area of ​​a certain size. This ensures that the tab and current collector have a sufficient effective welding area while avoiding excessively large welding areas that could lead to overheating and compromise welding quality. This, in turn, helps ensure the welding quality of the tab and the electrode sheet, improves the welding strength and stability of the tab, and guarantees the performance and reliability of the lithium-ion battery. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the electrode tab welding structure in one embodiment;

[0020] Figure 2 This is a schematic diagram of the planar structure of the electrode lug welding structure in one embodiment;

[0021] Figure 3 This is a schematic diagram of the structure of the electrode lug and the welding groove in one embodiment;

[0022] Figure 4 This is a schematic diagram of the electrode tab in one embodiment;

[0023] Figure 5 This is a schematic diagram of the structure of a lithium-ion battery in one embodiment.

[0024] In the picture:

[0025] 100, Electrode; 110, Current collector; 120, First active material layer; 130, Second active material layer; 140, Welding groove; 150, Clearance groove; 160, Empty foil area; 200, Tab; 210, Connecting part; 220, Welding part; 221, Welding stamp area; 222, Welding surface; 300, Insulating tape; 400, Protective gasket;

[0026] 11. Positive electrode plate; 12. Negative electrode plate; 21. Positive electrode tab; 22. Negative electrode tab. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0028] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0031] like Figures 1 to 4 As shown, an electrode tab welding structure of this embodiment includes an electrode sheet 100 and an electrode tab 200. The electrode sheet 100 includes a current collector 110 and a first active material layer 120 and a second active material layer 130 disposed on both sides of the current collector 110 in the thickness direction. The edge of the first active material layer 120 is provided with a welding groove 140 for placing the electrode tab 200 along the width direction. The welding groove 140 extends through the thickness direction of the first active material layer 120 to the surface of the current collector 110.

[0032] The electrode tab 200 includes a connecting part 210 and a welding part 220. The connecting part 210 is connected to an external circuit. The welding part 220 is disposed in a welding groove 140. The welding part 220 is welded to the current collector 110 to form a solder area 221. The area of ​​the solder area 221 is set as A. The side of the welding part 220 that is welded to the current collector 110 is set as a welding surface 222. The area of ​​the welding surface 222 is set as S, where 1 / 8S < A < 1 / 4S.

[0033] In this embodiment, a welding groove 140 is provided for the tab 200 to be inserted and partially welded to the current collector 110 within the welding groove 140. The tab 200 includes a welding portion 220 disposed in the welding groove 140 and a connecting portion 210 disposed outside the welding groove 140 for connection with an external circuit. Furthermore, the welding portion 220 and the current collector 110 are welded to form a solder area 221 of a certain size. This ensures that the tab 200 and the current collector 110 have a certain effective welding area 222, while avoiding excessively large welding areas that could lead to excessively high local welding temperatures and damage to the welding quality. This helps to ensure the welding quality of the tab 200 and the electrode sheet 100, improves the welding strength and stability of the tab 200, and guarantees the performance and reliability of the lithium-ion battery.

[0034] In one embodiment, such as Figure 3 As shown, the length of the welding portion 220 placed in the welding groove 140 is set as H, and the length of the solder area 221 along the length direction of the welding portion 220 is set as h, where 1 / 3H < h < 1 / 2H. Further, the width of the welding portion 220 is set as D, and the width of the solder area 221 along the width direction of the welding portion 220 is set as d, where 1 / 3D < d < 1 / 2D. This ensures that the area of ​​the solder area 221 is kept within a certain range, effectively guaranteeing that the tab 200 and the current collector 110 have a certain effective welding surface area 222, while avoiding excessively large welding surface area 222 which could lead to excessively high local welding temperatures and damage to the welding quality. This helps to ensure the welding quality of the tab 200 and the electrode 100, improves the welding strength and stability of the tab 200, and guarantees the performance and reliability of the lithium-ion battery.

[0035] In one embodiment, the width of the welding portion 220 is smaller than the width of the welding groove 140, and the two sides of the welding portion 220 in the width direction are respectively spaced apart from the first active material layer 120 to form empty foil areas 160. Further, the welding portion 220 is located in the middle of the welding groove 140, and the empty foil areas 160 on both sides of the welding portion 220 are the same size. This avoids damage to the first active material layer 120 on both sides of the welding portion 220 in the width direction during the welding process, thus preventing material loss.

[0036] Furthermore, the soldering area 221 is centrally located within the soldering surface 222 to avoid damage to the first active material layer 120 during the soldering process, which could lead to material loss and affect the performance of the first active material layer 120, thereby helping to ensure the overall performance of the electrode 100.

[0037] In one embodiment, the thickness of the tab 200 is greater than the depth of the welding groove 140. The edge of the first active material layer 120 is provided with a relief groove 150 along the width direction. The relief groove 150 and the welding groove 140 are arranged alternately along the length direction of the electrode 100, and the positions of the relief grooves 150 of the two mating electrode 100 are corresponding to the positions of the tab 200.

[0038] In one embodiment, insulating tape 300 is provided on the inner side of the clearance groove 150 to provide insulation protection for the tab 200 of the other electrode 100, and to prevent short circuits or other situations from occurring when the two electrodes 100 are attached.

[0039] In one embodiment, a protective gasket 400 is provided on the side of the clearance groove 150 facing the current collector 110. The protective gasket 400 provides insulation. When two mating electrode plates 100 are mated, the protective gasket 400 abuts against the electrode tab 200, which also protects the electrode tab 200 and the electrode plate 100 from collision or friction, preventing damage to the electrode tab 200 or the electrode plate 100. Furthermore, the gasket abutting against the electrode tab 200 further ensures the stability of the electrode tab 200 and reduces the risk of the electrode tab 200 falling off.

[0040] On the other hand, such as Figure 5 As shown, a lithium-ion battery is also provided, including the above-mentioned electrode tab welding structure, wherein the electrode 100 includes a positive electrode 11 and a negative electrode 12, and the electrode tab 200 includes a positive electrode tab 21 and a negative electrode tab 22. The positive electrode tab 21 is welded to the positive electrode 11, and the negative electrode tab 22 is welded to the negative electrode 12. When the positive electrode 11 and the negative electrode 12 are attached, the position of the positive electrode tab 21 is correspondingly set to the position of the clearance groove 150 on the negative electrode 12, and the position of the negative electrode tab 22 is correspondingly set to the position of the clearance groove 150 on the positive electrode 11.

[0041] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A tab welding structure characterized by, The electrode tab (200) includes a connecting part (210) and a welding part (220), the connecting part (210) is connected with an external circuit, the welding part (220) is arranged in the welding groove (140), the welding part (220) is welded with the current collector (110) to form a welding mark area (221); the area of the welding mark area (221) is set as A, one side of the welding part (220) welded with the current collector (110) is set as a welding surface (222), the area of the welding surface (222) is set as S, 1 / 8S The length of the welding part (220) arranged in the welding groove (140) is set as H, the length of the welding mark area (221) along the length direction of the welding part (220) is set as h, 1 / 3H 2. The tab weld structure of claim 1, wherein The width of the welding part (220) is set as D, the width of the welding mark area (221) along the width direction of the welding part (220) is set as d, 1 / 3D 3. The tab weld structure of claim 2, wherein, The width of the welding part (220) is smaller than the width of the welding groove (140), and the two sides of the welding part (220) along the width direction are arranged to be spaced apart from the first active material layer (120) to form an empty foil area (160).

4. The tab weld structure of any one of claims 1 to 3, wherein The welding part (220) is arranged in the middle of the welding groove (140), and the empty foil areas (160) on both sides of the welding part (220) are of the same size.

5. The tab weld structure of claim 4, wherein, The welding mark area (221) is arranged centrally in the welding surface (222).

6. The tab weld structure of any one of claims 1 to 3, wherein The thickness of the electrode tab (200) is greater than the depth of the welding groove (140), the edge of the first active material layer (120) is arranged with a relief groove (150) along the width direction, the relief groove (150) and the welding groove (140) are arranged in sequence along the length direction of the electrode tab (100), and the positions of the relief grooves (150) of two abutting electrode tabs (100) correspond to the position of the electrode tab (200).

7. The tab weld structure of any one of claims 1 to 3, wherein The inner side of the relief groove (150) is provided with an insulating adhesive tape (300).

8. The tab weld structure of claim 7, wherein, The side of the relief groove (150) facing the current collector (110) is provided with a protective gasket (400), and when two abutting electrode tabs (100) are abutted, the protective gasket (400) abuts against the electrode tab (200).

9. The tab weld structure of claim 7, wherein, ​ 10. A lithium-ion battery, characterized by, The tab welding structure as claimed in any one of claims 1 to 9, the tab (200) comprises a positive tab (21) and a negative tab (22), the positive tab (21) is welded on the positive tab sheet (11), the negative tab (22) is welded on the negative tab sheet (12), when the positive tab sheet (11) and the negative tab sheet (12) are attached, the position of the positive tab (21) corresponds to the position of the avoiding slot (150) on the negative tab sheet (12), the position of the negative tab (22) corresponds to the position of the avoiding slot (150) on the positive tab sheet (11).

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