Connecting structure of tab and battery cell cover plate and battery cell

Abstract

The invention relates to the technical field of batteries, and particularly discloses a connecting structure of a tab and a battery cell cover plate and a battery cell, a tab precursor comprises a plurality of substrates stacked along a first direction, each substrate is led out from one end of a pole piece of a pole group along a second direction, a first welding mark is formed after the plurality of substrates are welded, and a second welding mark is formed after the plurality of substrates are welded. The tab precursor is cut along a cutting line to form a tab, the cutting line extends along a third direction and penetrates through the first welding mark, the part, which is not cut off, of the tab is a welding part, the welding part is welded with a pole integrated on the cover plate body to form a second welding mark, and then circuit connection between the pole group and the pole is realized. The arrangement of a connecting piece is omitted, the tabs of the pole group are directly welded on the pole columns, the assembly process is simple, the space utilization rate is high, and the energy density is favorably improved. The invention also provides a battery cell which comprises the connecting structure of the tab and the battery cell cover plate.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a connection structure between a tab and a cell cover, and a battery cell. Background Technology

[0002] Lithium-ion batteries currently possess relatively mature technology and are a hot research topic in power batteries. The battery cell, as the core component of a lithium-ion battery, mainly consists of an aluminum casing, a cell cover, and electrode assemblies. The electrode assemblies are housed within the aluminum casing, and the cell cover connects to the aluminum casing to encapsulate the electrode assemblies. The electrode tabs of the electrode assemblies are typically connected to the terminals integrated on the cell cover via connecting tabs. The assembly process is relatively complex, involves many types of components, and results in high production costs. Summary of the Invention

[0003] The purpose of this invention is to provide a connection structure between the electrode tab and the cell cover plate, and a cell, which directly welds the electrode tab of the electrode group to the electrode post, eliminating the need for connecting pieces, reducing assembly processes, saving internal space of the cell, which is beneficial to improving energy density and reducing costs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] On one hand, the present invention provides a connection structure between the electrode tab and the cell cover plate, comprising:

[0006] A cell cover plate includes a cover plate body and a terminal post, wherein the terminal post is integrated on the cover plate body;

[0007] A tab precursor includes a plurality of substrates stacked along a first direction, each substrate being led out from one end of the electrode of the electrode group along a second direction, and the plurality of substrates being welded together to form a first solder mark, the first solder mark being located in the middle region of the tab precursor.

[0008] The tab is cut along the cutting line to form a tab. The cutting line extends in a third direction and passes through the first weld mark. The part of the tab that is not cut off is the first weld mark. The weld mark is welded to the pole post to form a second weld mark.

[0009] Wherein, the dimension of the electrode front body along the second direction is A;

[0010] The range of values ​​for A is: 26mm≤A≤32mm.

[0011] Optionally, the dimension of the welded portion along the second direction is D, and the dimension of the welded portion along the third direction is C;

[0012] The value range of D is: 4.5mm≤D≤9.5mm;

[0013] The value of C is in the range of 15mm≤C≤20mm.

[0014] Optionally, before the tab front body is cut along the cutting line, the dimension of the first solder mark along the second direction is B;

[0015] The relationship between D and B satisfies: 0.5mm ≤ BD ≤ 3mm;

[0016] The value of B is in the range of 5mm ≤ B ≤ 10mm.

[0017] Optionally, along the second direction, the distance between the side of the welded portion near the electrode assembly and the root of the electrode tab is G1;

[0018] The value range of G1 is: 6mm≤G1≤14mm.

[0019] Optionally, the welding part is centrally disposed on the electrode tab along a third direction; at the end of the electrode tab away from the electrode group, the distance between the side of the welding part disposed opposite to the electrode tab along a third direction and the adjacent side of the electrode tab disposed opposite to the electrode tab along a third direction is t1;

[0020] The value range of t1 is: 1.0mm≤t1≤3.0mm.

[0021] Optionally, the second solder mark is located in the central region of the welded portion, the dimension of the second solder mark along the second direction is E, and the dimension of the second solder mark along the third direction is F;

[0022] The value range of E is: 1.0mm≤E≤2.5mm;

[0023] The value range of F is: 10mm≤F≤20mm.

[0024] Optionally, the second solder mark is centered on the welded portion along the second direction.

[0025] Optionally, along the second direction, the distance between the side of the weld portion facing away from the electrode group and the side of the second solder mark facing away from the electrode group is G2;

[0026] The value range of G2 is: 1.0mm≤G2≤3.0mm.

[0027] Optionally, at the end of the electrode tab away from the electrode group, the distance between the side of the second solder mark away from the center of the cover plate body along the third direction and the adjacent side of the welded part that is opposite to it along the third direction is t2;

[0028] The range of t2 is: 1.0mm≤t2≤3.0mm.

[0029] On the other hand, the present invention provides a battery cell including the connection structure between the electrode tab and the battery cell cover plate in any of the above embodiments.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention provides a connection structure between a tab and a cell cover plate. The tab front body includes multiple substrates stacked along a first direction. Each substrate extends from one end of a electrode in a second direction. The multiple substrates are welded together to form a first solder mark located in the central region of the tab front body. The tab front body is cut along a cutting line to form a tab. The cutting line extends along a third direction and passes through the first solder mark. The uncut portion of the first solder mark in the tab is the welding part. This welding part is welded to a terminal post integrated on the cover plate body to form a second solder mark, thereby achieving a circuit connection between the electrode group and the terminal post. This invention eliminates the need for connecting tabs, directly welding the tab of the electrode group to the terminal post, reducing assembly processes, saving internal space in the cell, improving energy density, and reducing costs.

[0032] The present invention also provides a battery cell, including the connection structure between the aforementioned electrode tab and the battery cell cover. Its assembly process is simple, the battery cell has a large internal space, high energy density, and low cost. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0034] Figure 1 This is a front view of the tab precursor and the electrode assembly provided in an embodiment of the present invention;

[0035] Figure 2 This is a left view of the tab precursor and the pole assembly provided in an embodiment of the present invention;

[0036] Figure 3 This is a front view of the electrode tab (after cutting the electrode tab precursor) and electrode assembly provided in an embodiment of the present invention;

[0037] Figure 4 This is a left view of the electrode tab (after the electrode tab front body is cut) and the electrode assembly provided in an embodiment of the present invention;

[0038] Figure 5 This is a front view of the battery cell cover, electrode tabs, and electrode assembly provided in an embodiment of the present invention.

[0039] Figure 6 for Figure 5 A magnified view of section I in the middle.

[0040] In the picture:

[0041] 10. Cell cover plate; 11. Cover plate body; 12. Terminal post; 20. Terminal tab front body; 21. First solder mark; 22. Cutting line; 200. Terminal tab; 210. Welding part; 211. Second solder mark; 30. Electrode group. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0046] like Figures 1-6 As shown, this embodiment provides a connection structure between the electrode tab and the cell cover plate for circuit connection between the electrode group 30 and the cell cover plate 10. The cell cover plate 10 includes a cover plate body 11 and an electrode post 12, with the electrode post 12 integrated on the cover plate body 11.

[0047] The tab precursor 20 includes multiple substrates stacked along a first direction. Each substrate extends from one end of the electrode of the electrode assembly 30 along a second direction. After the multiple substrates are welded together, a first solder mark 21 is formed. The first solder mark 21 is located in the middle region of the tab precursor 20 to facilitate welding operations. After the multiple substrates are welded into a single structure, the connection strength between adjacent substrates is high. Further, after the tab precursor 20 is cut along the cutting line 22, the side connected to the electrode assembly 30 forms a tab 200. The cutting line 22 extends along a third direction and passes through the first solder mark 21. The uncut portion of the first solder mark 21 in the tab 200 is the welded portion 210. By adopting this cutting method, on the one hand, the area where the first solder mark 21 is not firmly welded around the edge is cut off, ensuring that the remaining part of the first solder mark 21 on the tab 200 has high welding strength and the connection between two adjacent substrates is reliable; on the other hand, it can ensure the flatness of the tab front body 20 at the cutting line 22 after cutting, and avoid the tab 200 formed after cutting the tab front body 20 cracking.

[0048] After the welding part 210 is welded to the electrode post 12, a second weld mark 211 is formed, realizing the circuit connection between the electrode group 30 and the electrode post 12. This invention eliminates the need for connecting tabs, directly welding the electrode tabs 200 of the electrode group 30 to the electrode post 12, reducing assembly processes, saving internal space in the battery cell, improving energy density, and reducing costs. Wherein, the aforementioned first direction is... Figure 2 The X-axis direction shown is the second direction. Figure 1 The Y-axis direction shown is the third direction. Figure 1 The Z-axis direction is shown in the figure.

[0049] See also Figures 1-4 In this embodiment, before the tab precursor 20 is trimmed, its dimension along the second direction is A, and the value of A is in the range of 26mm ≤ A ≤ 32mm. For example, the value of A can be 26mm, 28mm, 30mm, or 32mm, etc. By limiting the value of A to the above range, sufficient space is ensured for welding of the tab precursor 20, and the area of ​​the first solder mark 21 in the YZ plane is large, thereby ensuring high connection strength between multiple substrates. At the same time, the tab precursor 20 also has sufficient trimming allowance along the second direction, which can ensure that the tab precursor 20 still has sufficient length to connect with the pole post 12 after subsequent trimming.

[0050] Furthermore, before the tab front body 20 is cut along the cutting line 22, the dimension of the first solder mark 21 along the second direction is B, and the dimension of the first solder mark 21 along the third direction is C. The value range of B is 5mm ≤ B ≤ 10mm, and the value range of C is 15mm ≤ C ≤ 20mm. For example, the value of B can be 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm, etc. The value of C can be 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm, etc. By limiting the values ​​of B and C to the above ranges, the area of ​​the first solder mark 21 in the YZ plane is larger, and the connection between multiple substrates is stable and reliable. In addition, limiting the value of C to the above ranges can ensure that the tab 200 can meet the overcurrent requirements.

[0051] Furthermore, after the tab precursor 20 is cut to form the tab 200, the dimension of the welding portion 210 on the tab 200 along the second direction is D, and the dimension of the welding portion 210 along the third direction is C. That is, along the second direction, the width of the portion of the first weld mark 21 that is cut off is BD. The length of the first weld mark 21 along the third direction remains unchanged. The value of D ranges from 4.5mm to 9.5mm. For example, the value of D can be 4.5mm, 5.0mm, 6.0mm, 7.0mm, 8.0mm, 9.0mm, or 9.5mm, etc. The relationship between D and B satisfies: 0.5mm ≤ BD ≤ 3mm. By limiting the value of BD within the above range, on the one hand, it can be ensured that the tab 200 does not crack after cutting, and at the same time, the alignment of multiple cut substrates at the top of the tab 200 (that is, the end of the tab 200 away from the electrode group 30) is good, avoiding short circuits and other problems caused by misalignment of the ends of the tab 200; on the other hand, it can ensure that the connection area between multiple substrates is large enough to meet the overcurrent requirements of the tab 200.

[0052] Along the second direction, the distance G1 between the side of the welded portion 210 near the electrode assembly 30 and the root of the tab 200 (i.e., the end where the tab 200 connects to the electrode assembly 30) is defined as follows: G1. The value of G1 ranges from 6mm to 14mm. For example, the value of G1 can be 6mm, 8mm, 10mm, 12mm, or 14mm. By limiting the value of G1 to the above range, the distance between the welded portion 210 and the root of the tab 200 is sufficiently large to meet the connection requirements between the tab 200 and the pole post 12, while also minimizing the heat impact generated during the welding of the tab 200 and the pole post 12, thus avoiding any adverse effects on the performance of the electrode assembly 30.

[0053] See also Figure 3The welding part 210 is centrally located on the tab 200 along a third direction. At the end of the tab 200 opposite to the electrode assembly 30, the distance between the opposite side of the welding part 210 along the third direction and the adjacent opposite side of the tab 200 along the third direction is t1. The value of t1 ranges from 1.0mm to 3.0mm. For example, the value of t1 can be 1.0mm, 1.5mm, 2.0mm, 2.5mm, or 3.0mm. By limiting the value of t1 to the above range, a certain space is maintained between the welding part 210 and the side of the tab 200 along the third direction, avoiding the risk of welding defects such as pinholes when welding multiple substrates stacked along the first direction, while also ensuring good alignment of the top of the tab 200.

[0054] See also Figure 5 and Figure 6 In this embodiment, the second weld mark 211 formed after the tab 200 and the post 12 are welded is located in the central region of the welded portion 210. The dimension of the second weld mark 211 along the second direction is E, and the dimension of the second weld mark 211 along the third direction is F. The value range of E is 1.0mm ≤ E ≤ 2.5mm, and the value range of F is 10mm ≤ F ≤ 20mm. For example, the value of E can be 1.0mm, 1.5mm, 2.0mm, or 2.5mm, etc. The value of F can be 10mm, 12mm, 15mm, 18mm, or 20mm, etc. By limiting the values ​​of E and F to the above ranges, the area of ​​the second weld mark 211 in the YZ plane is larger, ensuring a stable and reliable connection between the tab 200 and the post 12, making it less likely for the tab 200 to separate from the post 12, and ensuring stable current transmission. Additionally, it should be noted that the second solder mark 211 should be located within the area of ​​the soldering part 210 so that the multilayer substrates can form a reliable connection with the pole post 12, i.e., E < D, F < C.

[0055] Furthermore, the second weld mark 211 is centrally positioned on the welding portion 210 along the second direction to ensure balanced force on both sides of the electrode tab 200 along the second direction. Along the second direction, the distance between the side of the welding portion 210 facing away from the electrode assembly 30 and the side of the second weld mark 211 facing away from the electrode assembly 30 is G2, and the value of G2 ranges from 1.0mm to 3.0mm. For example, the value of G2 can be 1.0mm, 1.5mm, 2.0mm, 2.5mm, or 3.0mm, etc. By limiting the value of G2 within the above range, a certain space is maintained between the second weld mark 211 and the top of the electrode tab 200, ensuring good welding quality between the electrode tab 200 and the electrode post 12 and avoiding welding defects such as pinholes.

[0056] At the end of the tab 200 away from the electrode assembly 30, the distance between the side of the second weld mark 211 away from the center of the cover plate body 11 along the third direction and the adjacent side of the welded part 210 arranged opposite to it along the third direction is t2. The value of t2 is in the range of 1.0mm ≤ t2 ≤ 3.0mm. For example, the value of t2 can be 1.0mm, 1.5mm, 2.0mm, 2.5mm or 3.0mm, etc. By limiting the value of t2 to the above range, a certain space is provided between the second weld mark 211 and the side of the welded part 210 along the third direction, avoiding the risk of poor welding when the tab 200 is welded to the electrode post 12.

[0057] This embodiment also provides a battery cell, including the connection structure between the tab and the cell cover plate in the above scheme. By reasonably optimizing the process parameters for welding multiple substrates of the tab front body 20, cutting the tab front body 20 to form the tab 200, and welding the tab 200 to the terminal post 12, the alignment of the top of the tab 200 can be effectively guaranteed, and the connection between the tab 200 and the terminal post 12 can be reliable.

[0058] Specifically, the battery cell includes two electrode groups 30 and a cell cover plate 10. The cell cover plate 10 includes a cover plate body 11 and two terminals 12. The two terminals 12 are spaced apart along a third direction, with one terminal 12 being the positive terminal and the other being the negative terminal. Each electrode group 30 has two tabs 200 extending from one end along a second direction. The two tabs 200 are a positive tab and a negative tab, respectively. Both the positive and negative tabs are cut using the same cutting method as the tab front body 20 described above. The positive tabs of both electrode groups 30 are assembled with the positive terminals using the same tab-to-cell cover plate connection structure as described above. Similarly, the negative tabs of both electrode groups 30 are also assembled with the negative terminals using the same tab-to-cell cover plate connection structure as described above.

[0059] In this embodiment, the battery cell eliminates the need for connecting tabs found in traditional battery cells. The positive tabs of the two electrode groups 30 are directly welded to the positive terminals, and the negative tabs of the two electrode groups 30 are directly welded to the negative terminals. After welding, the four tabs 200 of the two electrode groups 30 are bent towards each other, and the two electrode groups 30 are joined together and arranged side-by-side. Then, the two electrode groups 30 are installed into the battery cell housing, and the cover plate body 11 is welded to the opening of the housing. The two electrode groups 30 are encapsulated by the battery cell cover plate 10 and the housing. Therefore, by adopting the tab-to-cell cover plate connection structure in this embodiment, the assembly process of the battery cell is reduced, internal space of the battery cell is saved, the cost of the battery cell is greatly reduced, and the energy density is high.

[0060] The following uses samples from specific implementation cases to verify the relevant dimensional design of the tab precursor 20 and tab 200 in the above-mentioned battery cell. For details, please refer to Table 1.

[0061] Table 1

[0062]

[0063] As can be seen from the above results, the value ranges of parameters A, B, C, D, E, F, and BD in Examples 1 to 7 meet their corresponding size limitations. During the process of cutting the tab precursor 20 to form the tab 200, and during the subsequent welding and assembly of the tab 200 and the terminal post 12, no tearing occurred on the side of the tab 200 near the welding part 210 (i.e., the side opposite to the first weld mark 21 of the tab precursor 20 along the third direction). The multilayer substrate of the tab 200 was undamaged, the connection strength between the multilayer substrates of the tab 200 was high, and the connection strength between the tab 200 and the terminal post 12 was also high. After the cell assembly is completed, the current carrying capacity of the tab 200 meets the requirements of high current carrying capacity, and the product is of good quality.

[0064] In Comparative Example 1, the values ​​of parameters A, B, C, D, E, and F are all less than the minimum value of their respective ranges, while the value of BD satisfies the range limitation. During the process of cutting the tab precursor 20 to form the tab 200, and during the welding of the tab 200 to the electrode post 12, the multilayer substrate of the tab 200 is far from the welding part 210 along the third direction. The welding pull-out force on the substrate of the tab 200 is moderate, ensuring connection strength without tearing. However, the current carrying capacity of the tab 200 formed after cutting the tab precursor 20 is insufficient, failing to meet the current carrying requirements of large currents. The tab 200 overheats severely during cell charging and discharging, shortening its service life and resulting in product defects.

[0065] In Comparative Example 2, the values ​​of parameters A, B, C, D, and BD are all greater than the maximum values ​​of their respective ranges, while the values ​​of E and F are less than the minimum values ​​of their respective ranges. At this time, a significant portion of the first solder mark 21 is removed during the cutting of the tab precursor 20, resulting in a smaller area of ​​the welded portion 210 in the YZ plane. This leads to lower connection strength between the multiple substrates of the tab 200. Furthermore, during the welding process between the tab 200 and the electrode post 12, the sides of the multiple substrates of the tab 200 are too close to the welded portion 210 along the third direction, resulting in a large pull-out force on the substrates of the tab 200 and a tendency for tearing to occur on the sides. Additionally, the area of ​​the second solder mark 211 during the welding of the tab 200 and the electrode post 12 in the YZ plane is also small, resulting in insufficient current carrying capacity of the tab 200, failing to meet the requirements for high current carrying capacity. This leads to severe overheating of the tab 200 during charging and discharging of the battery cell, shortening its service life and causing product defects.

[0066] In Comparative Example 3, the values ​​of parameters A, B, C, D, E, F, and BD are all greater than the maximum value of their respective ranges. At this time, the area of ​​the second weld mark 211 when the tab 200 is welded to the terminal post 12 in the YZ plane is relatively large, the current carrying capacity of the tab 200 is sufficient to meet the current carrying requirements of large currents, the tab 200 does not overheat during charging and discharging, and its service life is relatively long. However, a large portion of the first weld mark 21 is removed during the cutting of the tab front body 20, resulting in a smaller area of ​​the welded part 210 in the YZ plane. The connection strength between the multiple substrates of the tab 200 is low, and the side of the second weld mark 211 along the third direction is too close to the side of the tab 200 along the third direction, resulting in excessive pull-out force during welding, which easily causes tearing of the side of the tab 200 along the third direction, leading to product defects.

[0067] Taking all factors into consideration, when the dimensions of cells A, B, C, D, E, F, and BD all meet the above-mentioned dimensional requirements, it can be guaranteed that there will be no tearing of the tab 200, the connection strength between the tab 200 and the terminal 12 is high, and the current carrying capacity of the tab 200 is good, meeting the current carrying requirements of large currents, and the cell product is of good quality.

[0068] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. 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 the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A connection structure between a tab and a cell cover plate, characterized in that, include: A battery cell cover plate includes a cover plate body and a terminal post, wherein the terminal post is integrated on the cover plate body; A tab precursor includes a plurality of substrates stacked along a first direction, each substrate being led out from one end of the electrode of the electrode group along a second direction, and the plurality of substrates being welded together to form a first solder mark, the first solder mark being located in the middle region of the tab precursor. The tab is cut along the cutting line to form a tab. The cutting line extends in a third direction and passes through the first weld mark. The part of the tab that is not cut off is the first weld mark. The weld mark is welded to the pole post to form a second weld mark. Wherein, the dimension of the electrode front body along the second direction is A; The range of values ​​for A is: 26mm≤A≤32mm.

2. The connection structure between the electrode tab and the cell cover plate according to claim 1, characterized in that, The dimension of the welded part along the second direction is D, and the dimension of the welded part along the third direction is C; The value range of D is: 4.5mm≤D≤9.5mm; The value of C is in the range of 15mm≤C≤20mm.

3. The connection structure between the electrode tab and the cell cover plate according to claim 2, characterized in that, Before the tab precursor is cut along the cutting line, the dimension of the first solder mark along the second direction is B; The relationship between D and B satisfies: 0.5mm ≤ BD ≤ 3mm; The value of B is in the range of 5mm ≤ B ≤ 10mm.

4. The connection structure between the electrode tab and the cell cover plate according to claim 1, characterized in that, Along the second direction, the distance between the side of the welded portion near the electrode assembly and the root of the electrode tab is G1; The value range of G1 is: 6mm≤G1≤14mm.

5. The connection structure between the electrode tab and the cell cover plate according to claim 1, characterized in that, The welding part is centrally located on the electrode tab along a third direction; at the end of the electrode tab away from the electrode group, the distance between the side of the welding part that is opposite to the electrode tab along a third direction and the adjacent side of the electrode tab that is opposite to the electrode tab along a third direction is t1; The value range of t1 is: 1.0mm≤t1≤3.0mm.

6. The connection structure between the electrode tab and the cell cover plate according to claim 1, characterized in that, The second solder mark is located in the middle region of the welded part, and the dimension of the second solder mark along the second direction is E, and the dimension of the second solder mark along the third direction is F; The value range of E is: 1.0mm≤E≤2.5mm; The value range of F is: 10mm≤F≤20mm.

7. The connection structure between the electrode tab and the cell cover plate according to claim 1, characterized in that, The second solder mark is centered on the welded portion along the second direction.

8. The connection structure between the electrode tab and the cell cover plate according to claim 1 or 7, characterized in that, Along the second direction, the distance between the side of the weld portion facing away from the electrode group and the side of the second solder mark facing away from the electrode group is G2; The value range of G2 is: 1.0mm≤G2≤3.0mm.

9. The connection structure between the electrode tab and the cell cover plate according to claim 1, characterized in that, At the end of the electrode tab away from the electrode group, the distance between the side of the second solder mark away from the center of the cover plate body along the third direction and the adjacent side of the welded part that is opposite to it along the third direction is t2; The range of t2 is: 1.0mm≤t2≤3.0mm.

10. A battery cell, characterized in that, The connection structure between the electrode tab and the cell cover plate as described in any one of claims 1-9 is included.

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