Battery cell and battery pack
By bending and welding the electrode through the holes of the connecting plate in the lithium-ion battery cell, the problem of thicker thickness of the connecting plate and the electrode is solved, and efficient utilization of the internal space of the battery cell and the improvement of production efficiency is achieved.
Patent Information
- Application Number
- CN202422132420.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-08-30
AI Technical Summary
In existing lithium-ion batteries, the connecting plate and the pole ear need to be bent when connecting, resulting in the thicker thickness of the connecting plate and the pole ear, occupying more internal space of the battery cell, reducing the space utilization rate.
The electrode ear is bent and welded after passing through the hole of the connecting piece. Only the electrode ear needs to be bent without bending the connecting piece. By setting welding openings and liquid injection holes on the shell, the manufacturing process is simplified and the space utilization is improved.
It reduces the space occupied by the battery cell, improves energy density, simplifies the manufacturing process, reduces production costs, and improves welding efficiency and shell strength.
Smart Images
Figure CN223066307U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of batteries, in particular to an electric core and a battery pack. Background Art
[0002] At present, a lithium-ion electric core is a large-capacity and high-power electric core. Due to its characteristics such as high energy density, long cycle life and low self-discharge rate, it has been widely used in many fields, such as consumer electronics, electric vehicle field, energy storage field, etc.
[0003] A lithium-ion electric core usually includes a housing, a pole group, pole columns, connection pieces, etc. The pole group is received in the housing and is formed by winding or laminating positive and negative electrode sheets and a separator. The tab of the pole group is connected to the pole column through a transfer piece, and the tab is located below the transfer piece. When the connection piece and the electrode sheet are connected, bending is required, which results in a relatively thick thickness after the connection piece and the tab are connected, occupying more internal space of the electric core, and the utilization rate of the internal space of the electric core is relatively low. Summary of the Utility Model
[0004] In view of this, the utility model provides an electric core and a battery pack to solve the problem that when the connection piece and the electrode sheet are connected, bending is required, resulting in a relatively thick thickness after the connection piece and the tab are connected and occupying more internal space of the electric core.
[0005] In a first aspect, the utility model provides an electric core, comprising: a housing having a receiving cavity with an open end, the housing including an end wall and a side wall surrounding the end wall, the end wall and the side wall enclosing the receiving cavity, and two welding openings spaced apart from each other, a liquid injection port located between the two welding openings, and two installation openings spaced apart from each other are formed on the end wall; two pole columns, the two pole columns are arranged in one-to-one correspondence with the two installation openings; a pole group disposed in the receiving cavity, one side of the pole group having a plurality of tab groups corresponding to the two welding openings, each tab group including two tabs; two connection pieces, each connection piece having a first connection portion and a second connection portion, the first connection portion is connected to the corresponding pole column, a through hole for the corresponding tab group to pass through is provided on the second connection portion, each tab passes through the corresponding through hole and then is bent to form a bent portion, and the bent portion is welded to the second connection portion through the corresponding welding opening.
[0006] Beneficial effects: When welding the connection piece and the tab, first insert the electrode into the accommodation cavity of the housing and sequentially pass the tab group through the corresponding through holes and welding openings. Then, after bending the tab, the bent portion is welded to the second connection portion of the connection piece by welding processes such as laser welding or ultrasonic welding. Only the tab needs to be bent, and there is no need to bend the connection piece. Compared with the connection method in the prior art where both the connection piece and the tab need to be bent during connection, the thickness after connection of the connection piece and the tab becomes thinner, which can reduce the space occupied inside the battery cell, contribute to improving the energy density of the battery cell, and enhance the space utilization rate inside the battery cell. Moreover, the bending process of the connection piece is reduced, simplifying the manufacturing process, improving production efficiency, reducing production costs, and also reducing the potential damage or deformation risk caused by bending the connection piece. Without bending the connection piece, material waste can be reduced and costs can be saved. The setting of the welding opening avoids the bending device and the welding device, which not only facilitates bending the tab but also facilitates welding the tab and the connection piece, improving welding efficiency and reducing costs. The two welding openings are spaced apart, so that the end wall is not completely disconnected in the middle, enhancing the self-strength of the end wall and thus enhancing the structural strength of the housing. The liquid injection hole is used to inject electrolyte into the battery cell. During the process of injecting electrolyte, gas may be generated inside the battery cell. The liquid injection hole can serve as an exhaust hole to release the gas and prevent the internal pressure of the battery cell from being too high. After the electrolyte injection is completed, the liquid injection hole is sealed by a sealing plug or the like to ensure the sealing of the internal environment of the battery cell and prevent electrolyte leakage or intrusion of external moisture. Setting the liquid injection hole directly on the end wall eliminates the need to open a liquid injection hole on the cover plate, facilitating welding the connection piece and the tab and injecting electrolyte on the same side of the battery cell. Operating on the same side of the housing can reduce operation complexity.
[0007] In an alternative embodiment, the battery cell further includes two sealing members, and the two sealing members are arranged in one-to-one correspondence with the two welding openings, and each sealing member seals the corresponding welding opening.
[0008] Beneficial effects: After welding the connection piece and the tab, the sealing member can effectively seal the welding opening, preventing external moisture and contaminants from entering the battery interior, ensuring the long-term performance and reliability of the battery, and also helping to prevent leakage of the electrolyte inside the battery and reducing potential safety hazards.
[0009] In an alternative embodiment, the battery cell further includes two insulating sheets, and the two insulating sheets are arranged in one-to-one correspondence with the two welding openings, and the sealing member is arranged above the insulating sheet.
[0010] Beneficial effects: The insulating sheet is used to isolate the sealing member from charged components such as the tab to prevent short circuits, and can also support internal components of the battery, such as the tab, to keep its position stable and avoid displacement during transportation or use.
[0011] In an alternative embodiment, a limiting structure is provided between the insulating sheet and the seal, and the limiting structure is used to limit the positions of the insulating sheet and the seal relative to each other.
[0012] Advantageous effects: The limiting structure can ensure the relative positions between the insulating sheet and the seal and restrict the movement therebetween, making the assembly more convenient during assembly and improving the assembly efficiency.
[0013] In an alternative embodiment, the limiting structure includes a limiting protrusion and a limiting groove. The limiting protrusion is provided on one of the insulating sheet and the seal, and the limiting groove is provided on the other of the insulating sheet and the seal.
[0014] Advantageous effects: The cooperation between the limiting protrusion and the limiting groove enables quick positioning between the insulating sheet and the seal, simplifies the assembly process, and helps improve the production efficiency.
[0015] In an alternative embodiment, the thickness T1 of the first connecting portion is 0.8 mm - 1.5 mm.
[0016] Advantageous effects: Setting the thickness T1 of the first connecting portion within a reasonable range can not only ensure the welding reliability between the connecting piece and the pole column, but also reduce the space occupied inside the battery cell, which helps improve the energy density of the battery cell and enhances the space utilization rate inside the battery cell.
[0017] In an alternative embodiment, the thickness T2 of the second connecting portion is greater than or equal to 1.5 mm.
[0018] Advantageous effects: Ensure the strength of the connecting piece itself, which is not easily bent during welding, and ensure that the laser does not penetrate the connecting piece when welding the pole ear, thereby improving the welding reliability.
[0019] In an alternative embodiment, the two welding openings are located between the two mounting openings.
[0020] In an alternative embodiment, the welding opening is rectangular.
[0021] In a second aspect, the present utility model further provides a battery pack, including: the above-mentioned battery cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0023] Figure 1A perspective view of a battery cell according to an embodiment of the present utility model;
[0024] Figure 2 is Figure 1 a top view of the battery cell shown;
[0025] Figure 3 is Figure 2 a cross-sectional view of the battery cell shown taken along the A-A direction;
[0026] Figure 4 is Figure 3 a partially enlarged view of the battery cell shown;
[0027] Figure 5 is Figure 2 a partial cross-sectional view of the battery cell shown taken along the B-B direction;
[0028] Figure 6 is Figure 1 a perspective view of two connecting pieces of the battery cell shown;
[0029] Figure 7 is Figure 6 a cross-sectional view of one of the connecting pieces shown;
[0030] Figure 8 is Figure 1 a perspective view of the electrode tab of the battery cell passing through the connecting piece shown;
[0031] Figure 9 is Figure 8 a perspective view of the cell body and the connecting piece shown;
[0032] Figure 10 is Figure 8 a perspective view of the electrode tab bent 90° shown;
[0033] Figure 11 is Figure 10 a perspective view of the cell body and the connecting piece shown.
[0034] Explanation of reference numerals:
[0035] 1. Housing; 101. End wall; 1011. Welding opening; 1012. Liquid injection hole; 102. Side wall;
[0036] 2. Cover plate;
[0037] 3. Terminal;
[0038] 4. Electrode group; 401. Electrode tab; 4011. Bending part;
[0039] 5. Connecting piece; 501. First connecting part; 502. Second connecting part; 5021. Through hole;
[0040] 6. Sealing member; 601. Limiting groove
[0041] 7. Insulating sheet; 701. Limit projection;
[0042] 8. First plastic part;
[0043] 9. Second plastic part;
[0044] 10. Sealing ring. Specific embodiments
[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.
[0046] The following will be combined with Figures 1 to 11 , to describe the embodiments of the present utility model.
[0047] According to an embodiment of the present utility model, on the one hand, a battery cell is provided, including: a housing 1, two pole columns 3, a pole group 4, and two connecting pieces 5. The housing 1 has a receiving cavity with an open end. The housing 1 includes an end wall 101 and a side wall 102 surrounding the end wall 101. The end wall 101 and the side wall 102 define the receiving cavity. Two welding openings 1011 are provided at intervals on the end wall 101, a liquid injection port located between the two welding openings 1011, and two installation openings provided at intervals; the two pole columns 3 are arranged in one-to-one correspondence with the two installation openings; the pole group 4 is arranged in the receiving cavity. One side of the pole group 4 has a plurality of pole ear groups corresponding to the two welding openings 1011, and each pole ear group includes two pole ears 401; each connecting piece 5 has a first connecting portion 501 and a second connecting portion 502. The first connecting portion 501 is connected to the corresponding pole column 3. A through hole 5021 for the corresponding pole ear group to pass through is provided on the second connecting portion 502. After each pole ear 401 passes through the corresponding through hole 5021, it is bent to form a bent portion 4011, and the bent portion 4011 is welded to the second connecting portion 502 through the corresponding welding opening 1011.
[0048] When applying the battery cell of this embodiment to weld the connecting piece 5 and the tab 401, first place the electrode assembly 4 into the accommodation cavity of the housing 1 and pass the tab assembly through the corresponding through holes 5021 and welding openings 1011 in sequence. Then, after bending the tab 401, weld the bent portion 4011 and the second connecting portion 502 of the connecting piece 5 together by welding processes such as laser welding or ultrasonic welding. Only the tab 401 needs to be bent, and there is no need to bend the connecting piece 5. Compared with the connection method in the prior art where both the connecting piece and the tab need to be bent during connection, the thickness after the connection of the connecting piece 5 and the tab 401 becomes thinner, which can reduce the space occupation inside the battery cell, help improve the energy density of the battery cell, and enhance the space utilization rate inside the battery cell. Moreover, the bending process of the connecting piece 5 is reduced, the manufacturing process is simplified, the production efficiency is improved, the production cost is reduced, and the potential damage or deformation risk caused by the bending of the connecting piece 5 is also reduced. Since the connecting piece 5 does not need to be bent, material waste can be reduced and costs can be saved.
[0049] Furthermore, the welding openings 1011 are arranged to avoid the bending equipment and the welding equipment, which not only facilitates the bending of the tab 401 but also the welding of the tab 401 and the connecting piece 5, improving the welding efficiency and reducing the cost. The two welding openings are arranged at intervals, so that the end wall is not completely disconnected in the middle, enhancing the self-strength of the end wall and thus the structural strength of the housing.
[0050] Specifically, as Figure 1 and Figure 2 shown, the liquid injection hole 1012 is used to inject electrolyte into the battery cell. During the process of injecting the electrolyte, gas may be generated inside the battery cell. The liquid injection hole 1012 can serve as an exhaust hole to release the gas and prevent the pressure inside the battery cell from being too high. After the electrolyte injection is completed, the liquid injection hole 1012 is sealed by a sealing plug or the like to ensure the sealing of the internal environment of the battery cell and prevent the leakage of the electrolyte or the intrusion of external moisture. The liquid injection hole 1012 is directly provided on the end wall, eliminating the need to open the liquid injection hole 1012 on the cover plate 2, which is convenient for welding the connecting piece 5 and the tab 401 and injecting the electrolyte on the same side of the battery cell. Operating on the same side of the housing 1 can reduce the operation complexity.
[0051] Furthermore, the end wall 101 and the side wall 102 are integrally formed without the need for welding connection, resulting in a high structural strength of the housing 1, which can better resist external impacts and pressures, reduce the risk of the battery cell malfunctioning when suffering an accidental impact, and thus ensure the safety and reliability of the battery cell.
[0052] In one embodiment, as Figures 1 to 4As shown, the battery cell further includes two seals 6, and the two seals 6 are arranged in one-to-one correspondence with the two welding openings 1011. Each seal 6 seals the corresponding welding opening 1011. After the connecting piece 5 and the tab 401 are welded, the welding opening 1011 can be effectively sealed by the seal 6, preventing external moisture and pollutants from entering the battery interior, ensuring the long-term performance and reliability of the battery, and also helping to prevent the leakage of the electrolyte inside the battery, reducing potential safety hazards.
[0053] Furthermore, the seal 6 is generally made of materials with high heat resistance, good chemical stability, and excellent sealing performance. These materials need to be able to withstand the high-temperature and high-pressure environment during battery operation and be compatible with the material of the housing 1 to ensure long-term sealing effectiveness. The material of the seal 6 can be metal materials such as stainless steel, aluminum, or aluminum alloy. It can be understood that the material of the seal 6 can also be composite materials that combine metal and plastic, etc.
[0054] Specifically, the seal is a sealing plate. Forming the seal with a plate is convenient for processing and manufacturing, reducing the manufacturing cost. The sealing plate is welded to the end wall 101, and the welding is firm and reliable, enhancing the overall structural strength.
[0055] In one embodiment, as Figure 4 shown, the battery cell further includes two insulating sheets 7, and the two insulating sheets 7 are arranged in one-to-one correspondence with the two welding openings 1011. The seal 6 is disposed above the insulating sheet 7. The insulating sheet 7 is used to isolate the seal 6 from charged components such as the tab 401 to prevent short circuits, and can also support internal battery components, such as the tab 401, to keep its position stable and avoid displacement during transportation or use.
[0056] Furthermore, the materials of the insulating sheets 7 are all plastics. Plastics have the advantages of electrical insulation, light weight, corrosion resistance, high structural strength, easy processing, strong plasticity, and good thermal stability.
[0057] In one embodiment, a limiting structure is provided between the insulating sheet 7 and the seal 6, and the limiting structure is used to limit the positions between the insulating sheet 7 and the seal 6. The limiting structure can ensure the relative positions between the insulating sheet and the seal and restrict the movement between the insulating sheet and the seal, making the assembly more convenient during assembly and improving the assembly efficiency.
[0058] Further, the limiting structure includes a limiting protrusion 701 and a limiting groove 601. The limiting protrusion 701 is disposed on one of the insulating sheet 7 and the seal 6, and the limiting groove 601 is disposed on the other of the insulating sheet 7 and the seal 6. The cooperation of the limiting protrusion 701 and the limiting groove 601 realizes the rapid positioning between the insulating sheet 7 and the seal 6, simplifies the assembly process, and helps to improve the production efficiency.
[0059] In one embodiment, asFigure 7 As shown, the thickness T1 of the first connecting portion 501 is 0.8 mm - 1.5 mm. The thickness of the first connecting portion 501 is also the Figure 7 vertical dimension of the first connecting portion 501 in [description]. The thickness of the first connecting portion 501 should neither be too large nor too small. If the thickness of the first connecting portion 501 is too small, it indicates that the welding strength between the connecting piece 5 and the pole column 3 is weak, and thus the welding reliability between the connecting piece 5 and the pole column 3 cannot be ensured. If the thickness of the first connecting portion 501 is too large, it means that the thickness of the connecting piece 5 is relatively thick, occupying a large amount of space inside the battery cell, and the utilization rate of the space inside the battery cell is relatively low. Therefore, setting the thickness T1 of the first connecting portion 501 within 0.8 mm - 1.5 mm, that is, setting the thickness T1 of the first connecting portion 501 within a reasonable range, can not only ensure the welding reliability between the connecting piece 5 and the pole column 3, but also reduce the space occupied inside the battery cell, contribute to improving the energy density of the battery cell, and enhance the utilization rate of the space inside the battery cell.
[0060] In one embodiment, as Figure 7 shown, the thickness T2 of the second connecting portion 502 is greater than or equal to 1.5 mm. The thickness T2 of the second connecting portion 502 is also the Figure 7 vertical dimension of the second connecting portion 502 in [description]. Setting the thickness T2 of the second connecting portion 502 to be greater than or equal to 1.5 mm can ensure the strength of the connecting piece 5 itself, making it not easily bent during welding, and ensuring that the laser does not penetrate the connecting piece 5 when welding the pole ear 401, thereby improving the welding reliability.
[0061] In one embodiment, in each pole ear group, the bending directions of the two pole ears 401 are opposite. When bending the pole ears 401, the bending head of the bending device can occupy the bending space before the pole ears 401 are bent, without the need to open too large a welding opening 1011 on the end wall 101 for avoidance, which can maximize the utilization rate in the width direction of the battery, and minimize the width of the welding opening 1011 on the end wall 101.
[0062] In one embodiment, the number of through holes 5021 is two, and the two through holes 5021 are arranged corresponding to the two pole ear groups one by one. At this time, the pole group 4 has four pole ear groups, and four pole ears 401 are welded on one connecting piece 5.
[0063] It can be understood that in another embodiment, the number of through holes 5021 is one, and one through hole is arranged corresponding to one pole ear group one by one. At this time, the pole group has 2 pole ear groups, and two pole ears 401 are welded on one connecting piece 5.
[0064] In one embodiment, the battery cell further includes a cover plate 2, two first plastic parts 8, a second plastic part 9, and two sealing rings 10. The cover plate 2 is disposed at the open end. The number of the pole columns 3 and the connecting pieces 5 is two. Each pole column 3 is installed at the installation opening through a first plastic part 8 and a sealing ring 10. The second plastic part 9 is disposed on the inner surface of the end wall 101. The first plastic part 8 is sleeved outside the corresponding pole column 3 and assembled at the corresponding installation opening. The first plastic part 8 can completely isolate the pole column 3 from the housing 1, prevent a short circuit between the pole column 3 and the housing 1, and ensure the electrical isolation between the pole column 3 and the housing 1. The second plastic part 9 is located inside the end wall 101 and is used to isolate the end wall 101 from the charged components such as the pole ear 401 inside the battery, preventing a short circuit; it can also support the internal components of the battery, such as the pole ear 401, to keep its position stable and avoid displacement during transportation or use. The sealing ring 10 is sleeved outside the pole column 3 and is in sealing fit with the end wall 101 and the first connecting portion 501, and is used to ensure the sealing performance of the battery, prevent the leakage of the electrolyte, and at the same time prevent the entry of external moisture and impurities into the interior of the battery cell.
[0065] Further, the two pole columns 3 are respectively a positive pole column and a negative pole column, the two connecting pieces 5 are respectively a positive pole connecting piece and a negative pole connecting piece. The positive pole connecting piece is welded to the positive pole column, and the negative pole connecting piece is welded to the negative pole column. The materials of the positive pole column and the negative pole column are metals. Generally, the material of the negative pole column is copper, aluminum, etc., and the material of the positive pole column is aluminum, etc.
[0066] It should be noted that before welding the connecting piece 5 and the pole ear 401, the pole column 3, the first plastic part 8, the second plastic part 9, and the sealing ring 10 have been assembled on the end wall 101, and the first connecting portion 501 of the connecting piece 5 has been fixed on the pole column 3.
[0067] In one embodiment, the two welding openings 1011 are located between the two installation openings.
[0068] It can be understood that in another embodiment, the two installation openings are located between the two welding openings.
[0069] In one embodiment, the welding opening 1011 is rectangular. It can be understood that the welding opening can also be other shapes and is not limited thereto.
[0070] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, including: the above-mentioned battery cell.
[0071] In the related art, both sides of the connecting piece are bent downward to form two lower bending portions. A pair of pole ears pass through between the two lower bending portions and are bent on the corresponding lower bending portions. When the connecting piece and the pole ear are welded, bending is required, resulting in a relatively thick thickness after the connection between the connecting piece and the pole ear, occupying more internal space of the battery, and the process is also complex.
[0072] In this embodiment, the first plastic part 8, the second plastic part 9, the positive pole column, the negative pole column, the sealing ring 10, the connecting piece 5, etc. are arranged on the end wall 101 of the housing 1. A welding opening 1011 for welding the connecting piece 5 and the pole tab 401 is arranged on the end wall 101. The vertical pole tabs 401 of the pole group 4 are first assembled above the connecting piece 5, and then bent 90°. Then, welding processes such as laser welding or ultrasonic welding are used to weld the connecting piece 5 and the pole tab 401 through the welding opening 1011, reducing the bending process of the connecting piece 5, improving the space utilization rate inside the battery, and enhancing the production efficiency.
[0073] Specifically, the connecting piece 5 is divided into a first connecting portion 501 and a second connecting portion 502. The first connecting portion 501 is welded to the pole column 3. Two through holes 5021 are formed in the second connecting portion 502, and two pole tab groups pass through the two through holes 5021 and are bent 90°. The bent pole tabs 401 are welded to the second connecting portion 502. The bending directions of the two pole tabs 401 of each pole tab group are opposite, that is, the two pole tabs 401 of each pole tab group are bent towards each other, which can save the space occupied by the bending device in the width direction, reduce the width of the welding opening on the end wall, and can maximize the utilization rate of the battery in the width direction; make the width of the welding opening on the end wall the smallest, and ensure the strength of the housing 1.
[0074] Furthermore, the welding opening 1011 is a stepped hole. The stepped surface of the welding opening 1011 is convenient for fixing the sealing plate. The upper surface of the second connecting portion 502 is higher than the upper surface of the first connecting portion 501, that is, the connecting piece 5 has a stepped structure. Since the surface of the pole tab 401 close to the pole plate of the pole group 4 is convex, the stepped structure can adapt to the structure of the pole tab 401 close to the pole plate side.
[0075] It should be noted that the upper surface of the first connecting portion 501 forms a welding area (such as Figure 6 the grid-like area shown), and the upper surface of the bending portion 4011 forms a welding area (such as Figure 10 the grid-like area shown).
[0076] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A battery cell, characterized in that, Comprising: A housing having a receiving cavity with an open end, the housing including an end wall and a side wall surrounding the end wall, the end wall and the side wall enclosing the receiving cavity, and two spaced welding openings, a liquid injection port located between the two welding openings, and two spaced mounting openings being formed in the end wall; Two pole columns, the two pole columns being arranged in one-to-one correspondence with the two mounting openings; A pole group disposed in the receiving cavity, one side of the pole group having a plurality of pole ear groups corresponding to the two welding openings, each pole ear group including two pole ears; Two connecting pieces, each connecting piece having a first connecting portion and a second connecting portion, the first connecting portion being connected to the corresponding pole column, a through hole for the corresponding pole ear group to pass through being provided in the second connecting portion, each pole ear being bent after passing through the corresponding through hole to form a bent portion, and the bent portion being welded to the second connecting portion through the corresponding welding opening.
2. The battery cell according to claim 1, characterized in that, The battery cell further includes two sealing members, the two sealing members being arranged in one-to-one correspondence with the two welding openings, and each sealing member sealing the corresponding welding opening.
3. The battery cell according to claim 2, wherein, The battery cell further includes two insulating sheets, the two insulating sheets being arranged in one-to-one correspondence with the two welding openings, and the sealing members being disposed above the insulating sheets.
4. The cell according to claim 3, wherein A limiting structure is provided between the insulating sheet and the sealing member, and the limiting structure is used to limit the positions between the insulating sheet and the sealing member.
5. The battery cell according to claim 4, characterized in that, The limiting structure includes a limiting protrusion and a limiting groove, the limiting protrusion being provided on one of the insulating sheet and the sealing member, and the limiting groove being provided on the other of the insulating sheet and the sealing member.
6. The battery cell according to any one of claims 1 to 5, characterized in that The thickness T1 of the first connecting portion is 0.8 mm - 1.5 mm.
7. The battery cell according to any one of claims 1 to 5, characterized in that The thickness T2 of the second connecting portion is greater than or equal to 1.5 mm.
8. The battery cell according to any one of claims 1 to 5, characterized in that, The two welding openings are located between the two mounting openings.
9. The battery cell according to any one of claims 1 to 5, characterized in that, The welding openings are rectangular.
10. A battery pack, characterized in that, Comprising: The battery cell according to any one of claims 1 to 9.