Electrode assembly, battery cell and secondary battery

Abstract

The utility model provides an electrode assembly, a battery cell and a secondary battery. The electrode assembly comprises pole pieces stacked along a first direction and pole lugs extending along a second direction, the tab is provided with a first end, a second end and a bending part positioned between the first end and the second end, and the first end is connected to the corresponding pole piece; and when the tabs are bent, the distance between the second ends of any two tabs is less than or equal to 2mm. According to the structure, the dislocation of the second end of the tab stacking body can be avoided, and the utilization rate of the internal space of the battery shell is improved; when a plurality of battery cell bodies are arranged in the shell, the adjacent tab stacking bodies can be prevented from being overlapped to other welding areas, pseudo soldering is avoided, and the welding reliability and the conductivity and safety of the battery are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a kind of electrode assembly, electric core and secondary battery. BACKGROUND

[0002] In the related art, in order to improve the space utilization rate inside the battery shell, for the structure of laminated core, the lug needs to be bent, wherein the lug is composed of multiple sub-lugs, since each sub-lug is connected to different parts of the core body, the length of each sub-lug is inconsistent, which causes the end of the bent lug away from the core body to be misaligned, and the lug misalignment may cause local accumulation, increase the local thickness of the core, and reduce the space utilization rate inside the battery shell. SUMMARY

[0003] Therefore, the utility model aims at providing an electrode assembly, an electric core and a secondary battery to prevent the end of the lug away from the core body from misaligning, to at least partially solve the problems in the related art.

[0004] To achieve the above purpose, the utility model provides an electrode assembly in the first aspect, comprising:

[0005] The pole piece is stacked along the first direction;

[0006] The lug extends from the pole piece along the second direction, the lug includes a first end, a second end and a bending portion between the first end and the second end, and the first end is connected to the corresponding pole piece;

[0007] In the second direction, the distance between the second ends of any two lugs is less than or equal to 2mm.

[0008] Optionally, the end faces of the second ends of any two lugs are coplanar.

[0009] Optionally, the lug includes a first segment between the bending portion and the first end and a second segment between the bending portion and the second end, and the bending portion is configured to bend the second segment relative to the first segment around a first rotation line;

[0010] The second segment includes a welding site for welding a connecting piece;

[0011] The lug has two side edges opposite along the first rotation line, and the side edges extend obliquely from the first end towards the second end.

[0012] Optionally, the angle between the side edge and the first rotation line is α;

[0013] α is 70° to 160°.

[0014] Optionally, the second section includes a transition site, the transition site is arranged between the welding site and the second end, and a width of the transition site is 0.5-3 mm.

[0015] Optionally, a width of the transition site is b, a thickness of the stack of the tab is c, and a thickness of the battery cell body provided with the tab is d, c≤b≤d.

[0016] Optionally, an end surface of an end of the connecting piece away from the battery cell body is recessed toward one side of the battery cell body to form a groove for accommodating the stack of the tab.

[0017] Optionally, a height of the groove is equal to a thickness of the second section, so that the end surface of the end of the connecting piece away from the battery cell body is flush with the end surface of the end of the second section away from the connecting piece.

[0018] The second aspect of the utility model further provides a battery cell, comprising: a battery cell body and the electrode assembly as described in the first aspect.

[0019] The electrode assembly comprises a positive electrode assembly and a negative electrode assembly arranged oppositely along the length direction of the battery cell body.

[0020] The positive electrode assembly comprises a positive tab, and the negative electrode assembly comprises a negative tab, both the positive tab and the negative tab are arranged to be bent toward the battery cell body, and the second section of the positive tab and the second section of the negative tab both extend in a first direction.

[0021] The end surface of the second end of the positive tab is coplanar with the end surface of the second end of the negative tab.

[0022] The third aspect of the utility model further provides a secondary battery, comprising the battery cell as described in the second aspect.

[0023] According to the above technical solution, the first end of the tab is connected to the corresponding tab in the battery cell body, when the tab is in the bent state, the second end of the tab can be cut in the form of cutting, so that the distance between the second ends of the two adjacent tabs is less than or equal to 2 mm, thereby avoiding the dislocation of the second end of the tab stack as much as possible, thereby improving the space utilization rate in the battery shell to a certain extent, and when a plurality of battery cell bodies are arranged in one battery shell, if the second end of the tab stack connected to the battery cell body is dislocated, the adjacent tab stack may be accidentally lapped to the welding area of the other battery cell body, resulting in unstable welding or virtual welding, affecting the conductivity and safety of the battery, and the end surface of the second end of the cut tab stack is a plane, which can effectively avoid lapping errors and improve the reliability of welding.

[0024] Other features and advantages of the present disclosure will be described in detail in the following detailed description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 is a structural schematic view of the cover plate assembly and the battery core body provided in the exemplary embodiment of the present disclosure;

[0027] Figure 2 is a structural schematic view of the cover plate assembly provided in the exemplary embodiment of the present disclosure;

[0028] Figure 3 is a structural schematic view of the tab in a folded state, wherein the second end of the tab is misaligned;

[0029] Figure 4 is a structural schematic view of the tab in a folded state, wherein the end face of the second end of the tab is a plane;

[0030] Figure 5 is a structural schematic view of the battery core provided in the exemplary embodiment of the present disclosure;

[0031] Figure 6 is Figure 5 is a partial enlarged schematic view of position A in FIG.

[0032] EXPLANATION OF REFERENCE NUMERALS

[0033] 1-battery core body; 2-tab; 201-first end; 202-second end; 203-folded part; 204-first section; 205-second section; 2051-welding site; 2052-transition site; 2053-receiving site; 3-cover plate body; 4-connection piece; 5-pole. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the specific embodiments and the drawings.

[0035] It should be noted that, unless otherwise defined, technical or scientific terms used in the embodiments of the present application should be understood as having the common meaning in the field of the present disclosure to which they belong. The terms "first", "second", and similar terms used in the present disclosure do not denote any order, number or importance, but are used to distinguish different components. The terms "comprise", "include" and similar terms mean that the elements or objects before the term encompass the elements or objects listed after the term and their equivalents, and do not exclude other elements or objects. The terms "connected" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationships, which may change accordingly when the absolute position of the described object changes.

[0036] In the related art, when the battery core body is installed inside the battery shell, the tab of the battery core body can be connected to the pole provided on the cover plate through the connecting piece. In view of the assembly process, the tab needs to be bent before the connecting piece and the tab are welded. However, since the tab is composed of multiple layers of sub-tabs, and each sub-tab connected to the battery core body is connected to a different position on the battery core body, during the tab bending process, the sub-tab near the outer side of the battery core body is stretched more due to the larger bending stress, while the sub-tab near the inner side of the battery core body is subjected to smaller stress. This will cause the outer tab to be "longer" than the inner tab after being folded, resulting in misalignment at the end away from the battery core body. If the misalignment of the tab is large at this time, it will cause some sub-tabs to be unable to be effectively connected, increase the internal resistance of the battery, and even cause local overheating or uneven performance. At the same time, the misalignment of the tab can cause local accumulation, increase the local thickness of the battery core, and thus reduce the space utilization inside the entire battery shell. Especially when multiple tabs are installed inside the battery shell, the misalignment of multiple tabs will reduce the assembly efficiency of personnel, and in severe cases, the battery core body cannot be well inserted into the shell, reducing the yield of the battery.

[0037] Furthermore, when multiple battery core bodies are provided in one battery shell, and the tabs connected to the battery core bodies are misaligned (as shown in Figure 3 The adjacent tabs may accidentally overlap the welding area of the other battery core body, causing unstable welding or virtual welding, affecting the conductivity and safety of the battery.

[0038] Based on this, the first aspect of the present application provides an electrode assembly, as shown in Figures 1 to 6As shown, the electrode assembly comprises: pole pieces stacked along a first direction, and tabs 2 extending out from the pole pieces along a second direction, wherein a plurality of tabs 2 are stacked to form a tab 2 stack, the tab 2 stack is capable of being welded with a connecting piece 4, the tab 2 comprises a first end 201, a second end 202, and a bending portion 203 between the first end 201 and the second end 202, the first end 201 is connected to the corresponding pole piece, and the distance between the second ends 202 of any two tabs 2 in the second direction is less than or equal to 2 mm.

[0039] For example, for ease of understanding, the first direction can refer to the thickness direction of the battery cell body 1, and the second direction can refer to the length direction of the battery cell body 1.

[0040] According to the above technical solution, the first end 201 of the tab 2 is connected to the corresponding pole piece in the battery cell body 1, and when the tab 2 is in a bent state, the second end 202 of the tab 2 can be cut in the form of cutting to make the distance between the second ends 202 of any two tabs 2 less than or equal to 2 mm, thereby avoiding the dislocation of the second ends 202 of the tab 2 stack as much as possible, thereby improving the space utilization rate in the battery shell to a certain extent. When a plurality of battery cell bodies 1 are arranged in a battery shell, if the second ends 202 of the tab 2 stacks connected to the battery cell bodies 1 are dislocated, the adjacent tab 2 stacks may accidentally overlap the welding area of other battery cell bodies 1, resulting in unstable welding or virtual welding, affecting the conductivity and safety of the battery. The end face of the second end 202 of the tab 2 stack after cutting is a plane, which can effectively avoid the overlap error and improve the reliability of welding.

[0041] In some embodiments, the second end 202 of the tab 2 stack in the bent state can be cut to make the distance between the second ends 202 of any two tabs 2 in the tab 2 stack less than or equal to 2 mm, wherein the cutting method can be ordinary mechanical mold cutting, non-contact cutting such as local high-temperature cutting of laser, or liquid cutting of other tools.

[0042] In another embodiment of the end face of the second end 202, the second end 202 after cutting, the end faces of the second ends 202 of any two tabs 2 are coplanar, thereby effectively avoiding the overlap error between the stacks of the adjacent two tabs 2 and improving the reliability of welding.

[0043] In some embodiments, referring to Figure 1 and Figure 4As shown, the tab 2 includes a first section 204 between the bending portion 203 and the first end 201, and a second section 205 between the bending portion 203 and the second end 202, and the bending portion 203 is configured such that the second section 205 is bent relative to the first section 204 around a first rotation line, wherein the first rotation line is a virtual line segment, which can be understood as a line segment extending along the width direction of the battery cell body 1 for ease of understanding. By bending the second section 205 relative to the first section 204 around the first rotation line, the tab 2 can be arranged compactly in a limited space, avoiding excessive length of the tab 2 to occupy additional space, which helps the battery cell to utilize the space more effectively, thereby improving the energy density of the entire battery system. At the same time, by cutting the second end 202 after bending, the end face of the second end 202 is kept flat and aligned neatly, which helps the precise butt joint of the tab 2 and the connecting piece 4 during welding, improves the welding precision and consistency, avoids problems such as virtual welding and missed welding, and thus improves the electrical performance and safety of the battery.

[0044] In some embodiments, with reference to Figure 1 and Figure 4 As shown, the bending portion 203 can absorb part of the mechanical stress, especially when the battery is subjected to external force or vibration during use, the bending portion 203 can effectively reduce the risk of fracture of the tab 2 at the welding point or the bending portion, and improve the mechanical strength and durability of the battery cell.

[0045] In some embodiments, with reference to Figure 1 and Figure 4 As shown, by cutting the tab 2 stack after bending, the length of the tab 2 stack can be shortened and the end face of the second end 202 of the tab 2 stack can be kept flat, which provides certain convenience for arranging multiple battery cells inside the battery shell, i.e., when there are multiple battery cell bodies 1 (multi-cell structure) in the battery shell, the tabs 2 connected to each battery cell body 1 can be arranged more closely, avoiding interference or lapping between adjacent tab 2 stacks, and ensuring smooth welding operation.

[0046] In some embodiments, with reference to Figure 1 and Figure 4 As shown in the present disclosure, by bending the tab 2 stack and cutting the second end 202 after bending, the shape and length of the entire tab 2 stack are more standardized, which makes it easier for automated equipment to handle the tab 2 (cutting, welding and other operations), improves production efficiency and reduces the necessity of manual intervention, and the neat arrangement of the tab 2 improves the operation precision of the automated equipment, thereby reducing errors in the production process.

[0047] And, by keeping the end face of the second end 202 of the tab 2 stack flat, the second end 202 is prevented from being misaligned, the tab 2 stack can more evenly contact the connecting piece 4, the contact resistance at the welding point is reduced, the current transmission efficiency of the battery cell is ensured, local heating or power loss caused by poor contact is avoided, and the overall conductivity and reliability of the battery cell are improved.

[0048] In some embodiments, with reference to Figure 5 and Figure 6 As shown, the tab 2 has two side edges opposite along the first rotation line, and the side edges extend obliquely from the first end 201 to the second end 202. When the tab 2 is bent along the first rotation line, the oblique side edges help to reduce stress concentration during bending, that is, the oblique side edges can evenly distribute bending stress compared to a perpendicular side edge structure, thereby reducing the risk of damage or cracking of the tab 2 at the bending point. This improves the bending flexibility and durability of the tab 2, making it less likely to break when repeatedly bent or subjected to external forces.

[0049] At the same time, the oblique side edges can simplify the operation of the automated equipment during the cutting and welding of the tab 2, especially when cutting after the tab 2 stack is bent. The oblique side edges can reduce the friction of the cutting tool and improve the flatness of the cutting. At the same time, due to the reduced misalignment between the tabs 2 during welding, the automated equipment can more efficiently perform welding operations, improving overall production efficiency.

[0050] In some embodiments, with reference to Figure 5 and Figure 6 As shown, the angle between the side edge and the first rotation line is a, and an exemplary angle of a is 70° to 160°, such as 70°, 80°, 90°, 100°, 120°, 140°, or 160°. If a is too small (less than 70°), the tab 2 has too many burrs, and the process is too difficult. If a is too large (greater than 160°), the root of the tab 2 is too wide, and the tab 2 root is prone to form redundancy later, which can cause damage to the battery cell. By reasonably setting the angle of a, the space inside the battery shell can be maximized. A larger oblique angle (such as close to 160°) helps to reduce the thickness of the tab 2 after bending, allowing the tab 2 to be more evenly and compactly arranged inside the battery, improving the overall space utilization and thus the energy density of the battery.

[0051] In some embodiments, with reference to Figure 5 and Figure 6As shown, the second section 205 includes a welding site 2051 for welding the connecting tab 4, wherein the welding site 2051 is arranged on the second section 205, which can ensure that the tab 2 is precisely docked with the connecting tab 4 during welding, thereby improving the precision of the welding process, reducing the risk of virtual welding or missed welding due to irregular shape or inconsistent length of the tab 2, and ensuring the firmness of the welding point and the reliability of the electrical connection. In addition, the arrangement of the welding site 2051 can simplify the production process. In particular, during the welding process, the clear welding site 2051 allows the relevant equipment to be more accurately aligned and welded, thereby reducing the workload of manual adjustment, improving production efficiency, and reducing welding failure or rework caused by positioning errors.

[0052] When a battery contains multiple cell bodies 1, the welding site 2051 can ensure that the welding site 2051 of each tab 2 is clearly arranged, avoiding the overlap of the welding area of the stack of adjacent tabs 2, and effectively reducing interference during welding.

[0053] In some embodiments, referring to Figure 5 and Figure 6 As shown, the second section 205 includes a transition site 2052 arranged between the welding site 2051 and the second end 202. The arrangement of the transition site 2052 can effectively disperse mechanical stress during welding, avoiding stress concentration problems that may occur when the welding site 2051 directly contacts the second end 202. By leaving a certain width of the transition region between the welding site 2051 and the second end 202, the stress on the welding point is more uniform, which helps to enhance the welding strength and improve the mechanical stability of the welding site.

[0054] In addition, if the welding site 2051 is directly connected to the second end 202 of the tab 2, excessive thermal stress or mechanical stress may be generated on the edge of the tab 2 during welding, which may cause damage. Therefore, the transition site 2052 also acts as a buffer region to prevent the heat or mechanical stress during welding from directly affecting the end of the tab 2, thereby reducing the risk of damage to the edge of the tab 2 and prolonging the service life of the cell.

[0055] In some embodiments, referring to Figure 5 and Figure 6 As shown, the width of the transition site 2052 is 0.5 to 3 mm. This interval distance does not occupy too much space of the tab 2, making the overall structure of the tab 2 more compact. That is, the transition site 2052 can provide sufficient buffer region without excessively increasing the overall size of the tab 2, thereby improving the utilization rate of the internal space of the battery as much as possible.

[0056] In some embodiments, referring to Figure 1 , Figure 4 , Figure 5 andFigure 6 As shown, the tab 2 in the present disclosure is suitable for the positive and negative tabs in the battery cell, and has better versatility.

[0057] In some embodiments, as shown in Figure 1 , Figure 2 , Figure 4 , Figure 5 and Figure 6 , when the stack of the tab 2 is in the bent state, a receiving site 2053 for receiving the connecting piece 4 is formed between the second section 205 and the battery cell body 1, that is, the receiving site 2053 formed after the tab 2 is bent can effectively utilize the limited space inside the battery cell, accurately receive the connecting piece 4 in the space between the battery cell body 1 and the tab 2, reduce the space waste caused by the random arrangement of the connecting piece 4 inside the battery cell, improve the space utilization of the battery, and help further compress the battery volume. At the same time, the receiving site 2053 provides a stable fixing position for the connecting piece 4, preventing the connecting piece 4 from being displaced or loosened due to vibration, thermal expansion or mechanical stress during battery operation, enhancing the stability of the internal structure of the battery, avoiding circuit short circuit or poor contact caused by the movement of the connecting piece 4, and improving the safety and reliability of the battery.

[0058] Moreover, by forming the receiving site 2053 after the stack of the tab 2 is bent, the connecting piece 4 can be more conveniently and accurately positioned in a specific area during assembly (the provision of the receiving site 2053 helps to more accurately position the connecting piece 4 and the tab 2 during welding, avoiding misalignment between the connecting piece 4 and the tab 2 during welding), reducing the alignment and adjustment time of the workers or equipment during assembly, optimizing the assembly process of the battery, and improving the assembly efficiency, thereby reducing the production cost to a certain extent.

[0059] In some embodiments, the end face of the connecting piece 4 away from the battery cell body 1 is recessed toward the side of the battery cell body 1 to form a groove for receiving the stack of the tab 2, that is, as shown in Figure 1 and Figure 2 , the groove can effectively receive the stack of the tab 2, reduce the exposure or disordered distribution of the stack of the tab 2, avoid possible poor contact or unstable connection problems, and improve the structural stability of the whole battery cell; at the same time, the height of the groove is equal to the thickness of the second section 205, so that the end face of the connecting piece 4 away from the battery cell body 1 is flush with the end face surface of the second section 205 away from the connecting piece 4, thereby making the whole battery cell surface flat, reducing the assembly difficulty, improving the space utilization of the battery cell, and reducing the possibility of misalignment and poor phenomenon during the assembly of the battery cell.

[0060] In some embodiments, the width of the transition site 2052 is b, the stack thickness of the tab 2 is c, and the thickness of the battery body 1 provided with the tab is d, c≤b≤d, that is, by ensuring that the thickness of the stack of the tab 2 is less than or equal to the width of the transition site 2052, the tab 2 can be effectively supported inside the battery, thereby improving the stability of the entire battery structure, and when the size relationship c≤b≤d is met, the space of the tab 2 and the transition site 2052 can be reasonably allocated while the thickness d of the battery body 1 is maintained, the internal space utilization of the battery is optimized, and the assembly process is easier to align, thereby improving the production efficiency of the battery and reducing the assembly difficulty of the battery.

[0061] On the basis of the above technical solutions, the second aspect of the utility model further provides a battery, comprising a battery body 1 and the electrode assembly of the above-mentioned first aspect or any embodiment of the above-mentioned first aspect, the electrode assembly comprising a positive electrode assembly and a negative electrode assembly oppositely arranged along the length direction of the battery body 1, the positive electrode assembly comprising a positive tab, and the negative electrode assembly comprising a negative tab, wherein the material selection and structural design of the positive tab and the negative tab are crucial to the thermal management performance of the battery, the positive tab is generally made of aluminum or aluminum alloy, so that the positive tab has good electrical conductivity, lightweight and oxidation resistance, and is suitable for matching the electrochemical characteristics of the positive material; the negative tab is usually made of copper or nickel-plated copper, so that the negative tab has excellent electrical conductivity and mechanical strength, and the positive tab and the negative tab are both folded towards the battery body 1, the second section 205 of the positive tab and the second section 205 of the negative tab both extend along the first direction, and the end face of the second end 202 of the positive tab is coplanar with the end face of the second end 202 of the negative tab, that is, the tab 2 is folded towards the battery body 1, and the end faces of the second sections 205 of the positive tab and the negative tab are coplanar, which ensures the compactness and surface flatness of the battery structure, helps to improve the assembly precision and production efficiency, and reduces the possibility of misalignment in the assembly process.

[0062] On the basis of the above technical solutions, the third aspect of the utility model further provides a secondary battery, comprising the battery of the above-mentioned second aspect, wherein the secondary battery further comprises a shell and a cover plate assembly, the shell has a cavity for accommodating the battery body 1, the cover plate assembly comprises a cover plate body 3, a connecting piece 4 and a pole 5, the pole 5 is arranged on the cover plate body 3, one end of the connecting piece 4 is connected to the pole 5, and the other end of the connecting piece 4 is connected to the stack of the tab 2, the cover plate body 3 covers the opening of the cavity, the battery body 1 is accommodated in the cavity of the shell, and the cover plate assembly accurately covers the opening, so that the cover plate body 3 can effectively seal the cavity where the battery is located, prevent dust, moisture or other contaminants from entering, improve the durability of the battery, reduce the aging speed of the internal components, and reduce the risk of liquid leakage and short circuit, thereby improving the long-term safety of the battery.

[0063] Those of ordinary skill in the art will understand that the above discussion of any of the embodiments is merely exemplary in nature and is not intended to imply that the scope of the disclosure, including the claims, is limited to these examples; the above embodiments or technical features among different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in detail for the sake of brevity.

[0064] Embodiments of the present application are intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the appended claims. Accordingly, any and all such alternations, modifications, permutations, combinations, sub-combinations, sub-combinations and variations are intended to fall within the scope of the present application as claimed.

Claims

1. An electrode assembly, characterized by, The electrode assembly comprises: polar pieces stacked along a first direction; tabs extending from the polar pieces along a second direction, the tabs comprising a first end connected to a corresponding polar piece, a second end, and a bent portion between the first end and the second end; in the second direction, a distance between the second ends of any two of the tabs is less than or equal to 2 mm.

2. The electrode assembly of claim 1, wherein, end faces of the second ends of any two of the tabs are coplanar.

3. The electrode assembly of claim 1, wherein, The tabs comprise a first section between the bent portion and the first end, and a second section between the bent portion and the second end, the bent portion being configured such that the second section is bent relative to the first section about a first rotation line; the second section comprises a welding site for a welding tab; the tabs have two side edges opposite along the first rotation line, the side edges extending obliquely from the first end toward the second end.

4. The electrode assembly of claim 3, wherein, an angle between the side edges and the first rotation line is a; a is 70° to 160°.

5. The electrode assembly of claim 4, wherein, The second section comprises a transition site between the welding site and the second end, the transition site having a width of 0.5 to 3 mm.

6. The electrode assembly of claim 5, wherein, The width of the transition site is b, a thickness of the stack of the tabs is c, and a thickness of a cell body provided with the polar pieces is d, c≤ b≤ d.

7. The electrode assembly of claim 3, wherein An end face of an end of the welding tab facing away from the cell body is recessed toward a side of the cell body to form a groove for receiving the stack of the tabs.

8. The electrode assembly of claim 7, wherein, A height of the groove is equal to a thickness of the second section, such that the end face of the end of the welding tab facing away from the cell body is flush with an end face of the end of the second section facing away from the welding tab.

9. An electric cell characterized by, The electrode assembly comprises: a cell body and an electrode assembly according to any one of claims 1 to 6; the electrode assembly comprises a positive electrode assembly and a negative electrode assembly disposed opposite along a length of the cell body; the positive electrode assembly comprises positive tabs, and the negative electrode assembly comprises negative tabs, the positive tabs and the negative tabs are both bent toward the cell body, and the second sections of the positive tabs and the negative tabs both extend along a first direction; end faces of the second ends of the positive tabs are coplanar with end faces of the second ends of the negative tabs.

10. A secondary battery characterized by comprising: The cell comprises the cell according to claim 9.

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