Battery cell and square shell battery

Abstract

The utility model provides a battery cell and a square-shell battery, and relates to the technical field of batteries. The cell has a winding center. The battery cell comprises a first pole piece, a first connecting piece and a first tab, the first pole piece comprises a plurality of straight sections, and at least part of the straight sections are connected with the first tab. The first tab comprises a first connecting part and a first bending part which are connected with each other, the first connecting part is connected with the straight section, and each first bending part is bent towards the winding center. The first bending parts of the plurality of first tabs are connected with the first connecting sheet, a first included angle alpha is formed between the first connecting part and the first bending part, and the first included angle alpha is greater than or equal to 90 degrees and less than or equal to 160 degrees. Therefore, the possibility that the tabs are reversely inserted to pierce the first pole piece can be reduced, the performance of the battery cell and the square-shell battery carrying the battery cell can be improved, and the possibility that the square-shell battery is short-circuited and the like to cause safety problems is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery cell and a prismatic battery. BACKGROUND

[0002] With the development of new energy technology, energy storage batteries are developing rapidly. Among them, prismatic batteries are more commonly used due to their large capacity, reliable packaging, high space utilization and other advantages.

[0003] However, the existing technology does not reasonably arrange the tab of the battery cell in the prismatic battery, which can easily cause the tab to pierce the pole piece, resulting in a decrease in the performance of the prismatic battery, and even a short circuit. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a battery cell and a prismatic battery, which can reduce the possibility of tab piercing the pole piece, improve the performance of the prismatic battery, and reduce the possibility of short circuit.

[0005] In a first aspect, the present application provides a battery cell having a winding center. The battery cell includes a first pole piece, a first connecting piece, and a first tab. The first pole piece includes a plurality of straight sections, and at least some of the straight sections are connected with the first tab. The first tab includes a first connecting portion and a first bending portion connected with each other. The first connecting portion is connected with the straight section, and each first bending portion is bent towards the winding center.

[0006] The first bending portion of each of the plurality of first tabs is connected with the first connecting piece, and a first included angle a is formed between the first connecting portion and the first bending portion. The first included angle a satisfies 90°≤a≤160°.

[0007] Through the above arrangement, the possibility of the first tab piercing the first pole piece by reverse insertion can be reduced, thereby improving the performance of the battery cell and the prismatic battery equipped with the battery cell, and reducing the possibility of short circuit in the prismatic battery and thus the occurrence of safety problems.

[0008] Optionally, in the distribution direction of the plurality of straight sections, the first bending portion of any adjacent first tab in the partial first tabs with the same bending direction has an overlapping portion.

[0009] Through the above arrangement, the first bending portion of the adjacent first tab can overlap, so that the plurality of first bending portions can support each other. When the first connecting piece is connected subsequently, the plurality of first bending portions can be in close contact with each other, thereby improving the welding quality and strength between the first tab and the first connecting piece.

[0010] Optionally, in the partial first tabs with the same bending direction, in the distribution direction of the plurality of straight sections, the length of the first bending portion of the first tab close to the winding center is less than the length of the first bending portion of the first tab away from the winding center.

[0011] The length of the first bending part is L1, and the distance between the opposite ends of the first bending part in the distribution direction of the plurality of straight sections is L2.

[0012] In this way, the plurality of first bending parts can be overlapped to accommodate the winding of the first pole piece.

[0013] Optionally, the first connecting piece has opposite first and second surfaces, the second surface is convex in a direction away from the first surface, and the second surface is connected to the plurality of first bending parts.

[0014] In this way, the second surface has a certain pushing effect on the first bending part, which can make the first connecting piece and the first bending part better fit, reduce the possibility of empty space between the plurality of first bending parts and between the first connecting piece and part of the first bending part, so as to facilitate subsequent connection.

[0015] Optionally, in a direction from the winding center of the battery cell to the outer side of the battery cell, the second surface has opposite first and second ends, and the second surface also has a top end opposite the winding center. The first end and the first surface have a first distance L1, the second end and the first surface have a second distance L2, and the top end and the first surface have a third distance L3.

[0016] L1, L2, and L3 satisfy L1≤L3 and L2≤L3.

[0017] Through the above-mentioned differentiated processing of the size of the first connecting piece, the second surface can act on the first bending part, so that the contact between the first bending parts is better, and the second surface and the first bending part can be in close contact.

[0018] Optionally, a bending position is formed at the connection position of the first connecting part and the first bending part. For any two adjacent first pole lugs, in a direction from the winding center of the battery cell to the outer side of the battery cell, the bending position of the first pole lug close to the winding center is flush with the bending position of the first pole lug away from the winding center.

[0019] Through the above-mentioned arrangement, the bending positions of the plurality of first pole lugs are on the same plane, so that the plurality of first pole lugs can be bent conveniently.

[0020] Optionally, the battery cell further includes a diaphragm, a second pole piece, a second connecting piece, and a plurality of second pole lugs. The plurality of second pole lugs are connected to the second pole piece. The diaphragm is located between the second pole piece and the first pole piece and is wound with the first pole piece and the second pole piece to form the battery cell. The second pole lug includes a second connecting part and a second bending part connected to each other. The second connecting part is connected to the second pole piece. Each second bending part is bent towards the winding center. The second bending parts of the plurality of second pole lugs are connected to the second connecting piece.

[0021] The first and second pole pieces can cooperate to convert chemical energy into electrical energy, and jointly maintain normal operation of the battery cell. The separator can isolate the first and second pole pieces to avoid the possibility of short circuiting of the battery cell caused by direct contact between the first and second pole pieces, so that the battery cell can operate safely.

[0022] Optionally, in the extension direction of the winding center, the first and second tabs are located on opposite sides of the battery cell.

[0023] Through the above arrangement, the first and second tabs can be located on opposite sides of the battery cell, which can facilitate subsequent separate welding of the first and second tabs, and reduce the possibility of mutual influence or even direct contact between the first and second tabs during welding, which can cause short circuit.

[0024] Optionally, the first pole piece further comprises a transition section connected to adjacent two straight sections, the plurality of straight sections are parallel to each other, the transition section is curved in a direction away from the straight section connected to the transition section, and the plurality of transition sections are distributed on opposite sides of the battery cell.

[0025] In the distribution direction of the plurality of transition sections, the straight section has one end and another end opposite to the one end, and the first tab on one straight section extends from the one end of the straight section to the other end of the straight section.

[0026] In this way, when the first tab is used for current transmission, the current path can be more, the transmission distance of the current can be reduced, the internal resistance of the prismatic battery can be reduced, and the rate performance of the prismatic battery can be increased, so that the energy conversion efficiency of the prismatic battery during storage and release of electrical energy is higher.

[0027] In a second aspect, the present application provides a prismatic battery comprising the battery cell of any one of the above first aspect.

[0028] The prismatic battery provided in the above second aspect and each possible design of the above second aspect can have the beneficial effects as described in the above first aspect and each possible embodiment of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A schematic view of a prismatic battery according to an embodiment of the present application.

[0030] Figure 2 A side view of a battery cell according to an embodiment of the present application.

[0031] Figure 3 A schematic view of a battery cell and a first connecting piece according to an embodiment of the present application.

[0032] Figure 4A schematic view of a first tab of an embodiment of the present application.

[0033] Figure 5 A schematic view of bending a first tab of an embodiment of the present application.

[0034] Figure 6 A schematic view of a first tab of an embodiment of the present application.

[0035] Figure 7 A schematic view of a first tab and a first connecting piece of an embodiment of the present application.

[0036] Figure 8 A schematic view of another first connecting piece of an embodiment of the present application.

[0037] Legend of reference signs:

[0038] 100: battery cell; 101: winding center; 10: first tab; 11: flat section; 12: transition section; 20: first connecting piece; 21: first face; 22: second face; 221: first end; 222: second end; 223: top end; 30: first tab; 31: first connecting portion; 32: first bending portion; 33: bending position; 200: square battery. DETAILED DESCRIPTION

[0039] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing the specific embodiments only and is not intended to be limiting of the application; the use of the terms "including", "comprising" and "having" and any variations thereof in this description and in the claims are intended to cover both the inclusive and exclusive cases.

[0041] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments. It is expressly understood that any of the features, structures, or characteristics described in connection with an embodiment can be included in a different embodiment.

[0042] The term "and / or", merely describes an associated relationship between associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are A, A and B, and B. In addition, the character " / " in this paper generally represents that the front and rear associated objects are an "or" relationship.

[0043] The orientation words appearing in the following description are the directions shown in the drawings, and are not limited to the specific structure of the flow limiting module of the present application. For example, in the description of the present application, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0044] In addition, the terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects, and are not used to describe a specific order, which can explicitly or implicitly include one or more of the features.

[0045] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more (including two), and similarly, "a plurality of groups" means two or more groups (including two groups).

[0046] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, the "connection" or "connection" of mechanical structure can mean physical connection, for example, physical connection can be fixed connection, for example, fixed connection through spacer, for example, fixed connection through screws, bolts or other spacers; physical connection can also be detachable connection, for example, mutual clamping or clamping connection; physical connection can also be integrally connected, for example, welding, bonding or integrally formed connection for connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] It should be understood that the reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described is included in at least one embodiment of the application. Therefore, appearances of "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, various particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0048] As shown in Figure 1 An embodiment of the application provides a square shell battery 200. The square shell battery 200 includes a battery cell 100 as shown in Figure 1

[0049] In this way, the battery cell 100 is carried in the square shell battery 200, and the square shell battery 200 can output electrical energy to the outside through the battery cell 100 or be connected to a power source for charging.

[0050] In the square shell battery 200 carrying the battery cell 100 provided by the application, the tab of the battery cell 100 is reasonably arranged, which can reduce the possibility of the tab damaging other components in the battery cell 100 and causing the performance of the square shell battery 200 to decrease, thereby improving the safety of the square shell battery 200 and reducing the possibility of problems such as leakage and short circuit.

[0051] It should be noted that the square shell battery 200 can serve as an energy source for an electrical device to provide the electrical device with the required electrical energy, so that the electrical device can work normally without an external power source.

[0052] The electrical device can be a new energy vehicle, an electric vehicle, a computer, a mobile phone, etc. The specific type of the electrical device is not limited in the embodiments of the application.

[0053] It should be further noted that the square shell battery 200 can be provided with one battery cell 100 or a plurality of battery cells 100. The plurality of battery cells 100 can be connected in series or in parallel, which can effectively utilize the space inside the square shell battery 200 and increase the capacity and energy density of the square shell battery 200.

[0054] The battery cell 100 provided by the embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0055] As shown in Figures 2 to 4 The application provides a battery cell 100 having a winding center 101. The battery cell 100 includes a first tab 10, a first connecting piece 20, and a first tab 30. The first tab 10 includes a plurality of flat sections 11, and at least part of the flat sections 11 are connected with the first tab 30.

[0056] ​Through the above arrangement, the first tab 30 is connected to the first tab sheet 10, and the first connecting sheet 20 is connected to the first tab 30. In this way, the first tab 30 can guide the current inside the battery cell 100 to the first connecting sheet 20, and then the first connecting sheet 20 can conveniently transmit the current to the power device provided with the square shell battery 200, so as to realize power supply to the power device.

[0057] Specifically, the first tab sheet 10 includes a plurality of flat sections 11, which are portions of the first tab sheet 10 that do not deform when the first tab sheet 10 is wound, and are located at relatively large straight faces of the battery cell 100.

[0058] The first tab 30 is connected to at least part of the flat section 11, which can reduce the possibility that the first tab 30 also deforms when the first tab sheet 10 is wound to form the battery cell 100, and then the first tab 30 is pierced.

[0059] As shown in Figure 5 and Figure 6 , the first tab 30 includes a first connecting portion 31 and a first bending portion 32 connected to each other. The first connecting portion 31 is connected to the flat section 11, and each first bending portion 32 is bent towards the winding center 101.

[0060] The first bending portions 32 of the plurality of first tabs 30 are connected to the first connecting sheet 20, and a first included angle α is formed between the first connecting portion 31 and the first bending portion 32, and the first included angle α satisfies: 90°≤α≤160°.

[0061] In the embodiment of the present application, the first tab 30 includes a first connecting portion 31 and a first bending portion connected to each other. The first tab 30 can be connected to the first tab sheet 10 through the first connecting portion 31, and connected to the first connecting sheet 20 through the first bending portion.

[0062] The first bending portion 32 is bent towards the winding center of the battery cell 100, so that the first connecting portion 31 intersects with the first bending portion 32, and a first included angle α is formed between the first connecting portion 31 and the first bending portion 32.

[0063] Since the first bending portion 32 is bent towards the winding center, the first bending portion 32 will be inclined towards the winding center 101, which makes the bending directions of the first tabs 30 located on both sides of the winding center 101 opposite.

[0064] In this way, the possibility that the first bending portion 32 protrudes from the first tab sheet 10 when the first bending portion 32 is bent outward can be reduced, which reduces the size of the battery cell 100, and then reduces the energy density of the battery cell 100.

[0065] In combination with Figure 5In the embodiment of the present application, the first tab 30 is bent once to obtain the first connecting portion 31 and the first bent portion 32 connected with each other, which can reduce the bending times of the first tab 30, reduce the height of the first tab 30, and further reduce the space occupied by the first tab 30 in the battery cell 100, thereby facilitating the improvement of the energy density of the battery cell 100.

[0066] The height of the first tab 30 is the distance between the opposite ends of the first tab 30 on the straight line where the winding center 101 is located.

[0067] In addition, in the present application, the first included angle α satisfies 90°≤α≤160°, so that the first bent portion 32 can be relatively far away from the first tab 10.

[0068] In this way, whether the first tab 30 is bent to form the first bent portion 32 or the first bent portion 32 is connected with the first connecting piece 20, the possibility of the first tab 30 being inserted and pierced into the first tab 10 can be reduced, thereby improving the performance of the battery cell 100 and the square cell battery 200 equipped with the battery cell 100, and reducing the possibility of short circuit of the square cell battery 200 and the occurrence of safety problems.

[0069] The first included angle α can be any value in the range of 90° to 160°, for example, 90°, 98°, 100°, 134°, 150°, 160°, and the like. The specific value of the first included angle α is not limited in the embodiment of the present application.

[0070] In addition, the specific setting of the first included angle α can also facilitate the connection of the first tab 30 and the first connecting piece 20. Compared with the mode of not bending the first tab 30 and directly connecting the side of the first tab 30 away from the first tab 10 with the first connecting piece 20, the first bent portion 32 and the first connecting piece 20 in the present application can increase the connection area of the first tab 30 and the first connecting piece 20, and improve the connection stability of the first connecting piece 20 and the first tab 30.

[0071] As a preferred embodiment, the first included angle α can be 90°, at which time the first bent portion 32 and the first connecting portion 31 are perpendicular to each other. On the one hand, the size of the first tab 30 extending from the first tab 10 as a whole can be reduced, the space occupied by the first tab 30 in the battery cell 100 can be reduced, the miniaturization of the battery cell 100 can be facilitated, and the energy density of the battery cell 100 can be improved.

[0072] On the other hand, the flatness of the first bent portion 32 can also be improved, so that the connection area of the first bent portion 32 and the first connecting portion 31 can be larger, and the connection stability of the first connecting piece 20 and the first tab 30 can be improved.

[0073] Furthermore, in the initial state where the first tab 30 is not bent, the angle between the first connecting part 31 and the first bent part 32 is 180°, and the two are coplanar.

[0074] Specifically, the first bending portion 32 can be formed by bending the first electrode tab 30 at a certain angle. After bending, the unbent portion of the first electrode tab 30 forms the first connecting portion 31. The bending angle is complementary to the aforementioned first included angle.

[0075] When bending multiple first tabs 30 to form multiple first bends 32, the bending angles of the multiple first tabs 30 can be the same. At this time, the first included angles are the same in the multiple first tabs 30 obtained after bending.

[0076] In this way, the same tooling can be used to bend multiple first tabs 30, reducing the possibility of adjusting the tooling midway and making the operation easier.

[0077] Of course, the bending angles of the multiple first electrode tabs 30 can also be different, so that when bending the first electrode tabs 30, the bending of the first electrode tabs 30 can be adapted to the winding of the first electrode sheet 10.

[0078] For example, for the first electrode tab 30 near the winding center 101, there are fewer first electrode tabs 30 in its bending direction, while for the first electrode tab 30 far from the winding center 101, there are more first electrode tabs 30 in its bending direction. When bending, it is more likely to be affected by other first electrode tabs 30.

[0079] At this time, during bending, the bending angle of the first electrode 30 located on the outer side can be greater than the bending angle of the first electrode 30 located on the inner side.

[0080] The inner side is the side of the battery cell 100 closest to the winding center 101, and the outer side is the side of the battery cell 100 furthest from the winding center 101.

[0081] Of course, when the bending angles of the multiple first tabs 30 are different, the size of the bending angles of the multiple first tabs 30 can also vary in other ways.

[0082] The bending angles of the multiple first tabs 30 are not specifically limited in this embodiment.

[0083] In some embodiments, such as Figure 4 As shown, the first electrode 10 may also include a transition section 12 connected to two adjacent straight sections 11. The multiple straight sections 11 are parallel to each other, and the transition section 12 is bent in a direction away from the straight section 11 to which it is connected. The multiple transition sections 12 are distributed on opposite sides of the cell 100.

[0084] In the embodiment of the present application, the first tab sheet 10 further comprises a transition section 12 connected between the flat sections 11. That is, the flat sections 11 and the transition sections 12 are sequentially adjacent and continuously distributed.

[0085] In the process of winding the first tab sheet 10 to form the battery cell 100, the flat sections 11 are not bent and remain in their original flat state, so that the plurality of flat sections 11 are parallel to each other. The transition section 12 is located between two adjacent flat sections 11 and is the part of the first tab sheet 10 that is bent during winding.

[0086] The transition section 12 is bent in a direction away from the flat section 11 connected thereto, so that the flat section 11 connected thereto can be distributed around the winding center 101.

[0087] That is, when the first tab sheet 10 is wound, the transition section 12 is located at the winding arc corner of the first tab sheet 10, and the flat section 11 is located at the relatively large straight face of the first tab sheet 10. Thus, it is beneficial to orderly and stably perform winding.

[0088] In addition, in the distribution direction of the plurality of transition sections 12, the flat section 11 has opposite ends, and the first tab 30 on one flat section 11 can extend from one end of the flat section 11 to the other end of the flat section 11.

[0089] Therefore, at the flat section 11 connected with the first tab 30, each position of the flat section 11 is connected with the first tab 30, which makes the distribution of the first tab 30 wider.

[0090] In this way, when the current is transmitted through the first tab 30, the current path can be more, the transmission distance of the current can be reduced, the internal resistance of the square case battery 200 can be reduced, and the rate performance of the square case battery 200 can be increased, so that the energy conversion efficiency of the square case battery 200 during storage and release of electric energy is higher, that is, the energy efficiency of the square case battery 200 can be improved.

[0091] In the embodiment of the present application, the first tab 30 connected on one flat section 11 can be a large long tab. Alternatively, it can also be a plurality of small tabs connected with each other. The specific setting mode of the first tab 30 is not limited in the embodiment of the present application.

[0092] It can be understood that no matter which setting mode is used, the first tab 30 can extend from one end of the flat section 11 to the other end of the flat section 11.

[0093] In some embodiments, as Figure 5 and Figure 7As shown, in the distribution direction of the plurality of flat sections 11, the first bending portions 32 of any adjacent first tabs 30 in the same bending direction can have overlapping portions.

[0094] Through the above arrangement, the first bending portions 32 of adjacent first tabs 30 can overlap, so that the plurality of first bending portions 32 can support each other, and when the first connecting piece 20 is subsequently connected, the close contact between the plurality of first bending portions 32 can be facilitated, and the welding quality and welding strength between the first tab 30 and the first connecting piece 20 can be improved.

[0095] In the embodiments of the present application, the plurality of first bending portions 32 can have different arrangement modes, and here, in order to facilitate understanding, the first tabs 30 in the direction from the winding center 101 to the outside of the battery cell 100 are distinguished as the first tab, the second tab, the third tab, and the like. Correspondingly, the plurality of first bending portions 32 are respectively referred to as the first bending position, the second bending position, and the third bending position.

[0096] The first tab 30 can be arranged by referring to the following description, so that adjacent first bending portions 32 have overlapping portions.

[0097] For example, every two first tabs 30 form a group, and the first bending portions 32 of the group of first tabs 30 overlap each other.

[0098] That is, the second bending position overlaps the first bending position, the third bending position overlaps the second bending position, and so on.

[0099] In this way, the overlap of every two first bending portions 32 can make the number of layers of the first bending portions 32 consistent at each position after all the first tabs 30 are processed, so that the planarity of the plurality of first bending portions 32 is high, and the connection of the first connecting portion 31 and the plurality of first bending portions 32 is facilitated.

[0100] Alternatively, the second bending position overlaps the first bending position. In the first tabs 30 located on the side of the second tab away from the winding center 101, each first bending portion 32 overlaps the first bending portions 32 of the two first tabs 30 adjacent thereto.

[0101] That is, the second bending position overlaps the first bending position, the third bending position overlaps the second bending position and the first bending position, the fourth bending position overlaps the third bending position and the second bending position, and so on.

[0102] Of course, the plurality of first bending portions 32 can also have other arrangement modes, which are not specifically limited in the embodiments of the present application.

[0103] By the above arrangement, the plurality of first bending portions 32 have overlaps therebetween, which makes the connection between the plurality of first bending portions 32 more reliable. In this way, the connection of the first connecting piece 20 and the plurality of first bending portions 32 can be facilitated, the connection strength of the first connecting piece 20 and the plurality of first bending portions 32 can be improved, and the reliability of the first tab 30 in transmitting current can be improved.

[0104] It should be noted that the material of the first tab 30 is generally a metal material such as aluminum or nickel, and has a small thickness and a certain flexibility.

[0105] Therefore, the mutual overlap of the first bending portions 32 has little effect on the thickness of the first tab 30 as a whole at the first bending portions 32, and there is also a certain deformation at the first bending portions 32 when the first bending portions 32 overlap, which further makes the thickness of the first tab 30 as a whole at the first bending portions 32 smaller.

[0106] That is, at the position where the first bending portions 32 overlap, the thickness of the plurality of first bending portions 32 at each position can be considered to be approximately the same, that is, the plurality of first bending portions 32 can be considered to be on the same plane. Figure 7 The thickness of the plurality of first bending portions 32 after overlapping is made larger only to facilitate the illustration of the overlapping condition.

[0107] In some embodiments, among the first tabs 30 with the same bending direction, in the distribution direction of the plurality of flat sections 11, the length of the first bending portion 32 of the first tab 30 close to the winding center 101 is smaller than the length of the first bending portion 32 of the first tab 30 away from the winding center 101.

[0108] The length of the first bending portion 32 is the distance between the opposite ends of the first bending portion 32 in the distribution direction of the plurality of flat sections 11.

[0109] By the above arrangement, the length of the first bending portion 32 of the first tab 30 close to the winding center 101 is smaller, and the length of the first bending portion 32 of the first tab 30 away from the winding center 101 is larger.

[0110] In this way, the plurality of first bending portions 32 can have overlapping portions therebetween to adapt to the winding of the first pole piece 10.

[0111] Specifically, as the first pole piece 10 continues to wind, the distance between adjacent flat sections 11 gradually increases. In this way, the possibility that the first bending portion 32 of the first tab 30 located on the outside is too small in length to overlap with the first bending portion 32 of the adjacent first tab 30 can be reduced.

[0112] In some embodiments, as Figure 7 andFigure 8 As shown, the first connecting sheet 20 has opposite first face 21 and second face 22, the second face 22 is convex in the direction away from the first face 21, and the second face is connected with the plurality of first bending portions 32.

[0113] According to the foregoing description, the first bending portion 32 of the plurality of first tabs 30 is with overlapping portion.

[0114] In the embodiment of the present application, the surface directly connected with the first connecting sheet 20 and the first bending portion 32 is also curved, so that the second face 22 is in a curved state.

[0115] Since the second face 22 is convex in the direction away from the first face 21, the middle part of the second face 22 is closer to the first tab 10 than the edge of the second face 22.

[0116] In this way, the second face 22 has a certain pushing effect on the first bending portion 32, so that the first connecting sheet 20 and the first bending portion 32 can be better fitted, and the possibility of voids between the plurality of first bending portions 32 and between the first connecting sheet 20 and part of the first bending portion 32 can be reduced, so as to facilitate subsequent connection.

[0117] In some embodiments, as shown in Figure 2 , Figure 7 and Figure 8 As shown, in the direction from the winding center 101 of the battery cell 100 to the outside of the battery cell 100, the second face has opposite first end 221 and second end 222, and the second face also has top end 223 opposite the winding center 101. The first end 221 and the first face 21 have a first distance L1, the second end 222 and the first face 21 have a second distance L2, and the top end 223 and the first face 21 have a third distance L3.

[0118] Wherein, L1, L2, L3 can satisfy: L1≤L3, L2≤L3. Therefore, the distance between the top end 223 and the first face 21 can be made larger, and the first end 221 and the second end 222 are closer to the first face 21, and the second face 22 in a curved state can be obtained.

[0119] Through the above setting, the size of the first connecting sheet 20 is differentially processed, so that the second face 22 can act on the first bending portion 32, so that the contact between the first bending portion 32 is better, and the second face 22 and the first bending portion 32 can be in close contact.

[0120] In the embodiment of the present application, the first distance L1 and the third distance L3 have a difference, which can satisfy 0.05mm≤L3-L1≤0.3mm. In this way, the second face 22 can be better connected with the plurality of first bending portions 32.

[0121] Specifically, the difference between the first distance L1 and the third distance L3 can be 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.3mm, etc., which can be set according to the winding number of the first tab 10, the thickness of the first lug 30, and other parameters. The present application embodiment is not limited here.

[0122] In addition, the difference between the second distance L2 and the third distance L3 can also satisfy 0.05mm≤L3-L2≤0.3mm. For details, please refer to the above description, which will not be repeated here.

[0123] In some embodiments, as shown in Figure 7 The first connecting portion 31 and the first bending portion 32 form a bending position 33 at the connecting position.

[0124] In the present application embodiment, for any two adjacent first lugs 30, in the direction from the winding center 101 of the battery cell 100 to the outside of the battery cell 100, the bending position 33 of the first lug 30 close to the winding center 101 can be flush with the bending position 33 of the first lug 30 away from the winding center 101.

[0125] It can be understood that Figure 7 is to facilitate the dislocation of the plurality of bending positions 33.

[0126] Through the above setting, the bending positions of the plurality of first lugs 30 are on the same plane, so that the plurality of first lugs 30 can be bent conveniently.

[0127] Specifically, the first lug 30 can be bent by a tool, and after adjusting the bending position of the tool once, the plurality of first lugs 30 can be bent to form a plurality of first bending portions 32.

[0128] In this way, the possibility of reducing the operation complexity and production efficiency caused by multiple adjustments of the tool can be reduced.

[0129] Of course, in the direction from the inside of the battery cell 100 to the outside of the battery cell 100, the height of the first connecting portion 31 can also gradually increase, which makes the bending position 33 also gradually increase, and can reduce the possibility of mutual influence between the plurality of first lugs 30 in the process of bending the plurality of first lugs 30.

[0130] The height of the first connecting portion 31 refers to the distance between the opposite ends of the first connecting portion 31 on the straight line where the winding center 101 is located.

[0131] In addition, the first tab 30 can be pre-bent before being bent by the tool.

[0132] In some embodiments, the battery cell 100 can further include a diaphragm, a second tab, a second connecting tab, and a plurality of second tabs connected to the second tab. The diaphragm is located between the second tab and the first tab 10 and is wound with the first tab 10 and the second tab to form the battery cell 100. The second tab includes a second connecting portion and a second bent portion connected to each other, the second connecting portion is connected to the second tab, and each second bent portion is bent towards the winding center 101, and the second bent portions of the plurality of second tabs are connected to the second connecting tab.

[0133] The diaphragm is located between the first tab 10 and the second tab and can be wound with the first tab 10 and the second tab to form the battery cell 100.

[0134] In the formed battery cell 100, the diaphragm can separate the first tab 10 from the second tab to avoid the possibility of short circuit caused by direct contact between the first tab 10 and the second tab, so that the battery cell 100 can operate safely.

[0135] The second tab is connected to the second tab, and the second tab can participate in the electrochemical reaction inside the battery cell 100 together with the second tab and lead the current inside the battery cell 100 to the power consumption device.

[0136] The second tab also includes a second connecting portion and a second bent portion, the second tab can be connected to the second tab through the second connecting portion, and the second bent portion is bent towards the winding center 101. This makes the second bent portion inclined towards the winding center 101, which can reduce the possibility of the second bent portion protruding from the second tab, resulting in a larger size of the battery cell 100, and thus reducing the energy density of the battery cell 100.

[0137] In addition, in the embodiments of the present application, the second tab is bent once to obtain the second connecting portion and the second bent portion connected to each other, which can also reduce the bending times of the second tab, reduce the height of the second tab, and thus reduce the space occupied by the second tab in the battery cell 100, which is conducive to improving the energy density of the battery cell 100.

[0138] The height of the second tab is the distance between the opposite ends of the second tab on the straight line where the winding center 101 is located.

[0139] In the embodiments of the present application, the second connecting portion and the second bent portion can have a second included angle β, and the second included angle β can satisfy: 90°≤β≤160°.

[0140] In this way, the second bending part can be relatively far away from the second pole piece. In this way, no matter when the second pole lug is bent to form the second bending part or when the second bending part is connected with the second connecting piece, the possibility of the pole lug being inserted into the second pole piece in reverse can be reduced, and thus the performance of the battery cell 100 and the square battery 200 equipped with the battery cell 100 can be improved, and the possibility of the square battery 200 short-circuiting and thus causing a safety problem can be reduced.

[0141] Specifically, the second included angle β can be any value in the range of 90° to 160°, for example, 90°, 98°, 100°, 134°, 150°, 160°, and the like. The specific value of the second included angle β is not limited herein.

[0142] It should be noted that the first pole piece 10 and the second pole piece have opposite polarities, so that the first pole piece 10 and the second pole lug can cooperate to convert chemical energy into electrical energy and jointly maintain the normal operation of the square battery 200.

[0143] The first pole piece 10 can be a positive pole piece, which is an electrode with a relatively high potential in the battery cell 100. In the discharge process, the positive pole piece undergoes a reduction reaction, that is, cations can be removed from the positive pole piece and migrate to the negative pole piece.

[0144] The second pole piece can be a negative pole piece, which is an electrode with a relatively low potential in the battery cell 100. In the discharge process, the negative pole piece undergoes an oxidation reaction, and cations can be embedded in the negative pole piece and stored.

[0145] It should be further noted that in the above embodiments, the first pole piece 10 is taken as an example for description, and the second pole piece can also be similarly configured.

[0146] For example, the second pole piece can also have a flat section 11, and the second pole lug extends from one end of the flat section 11 of the second pole piece to the other end.

[0147] For another example, the side of the second connecting piece facing the second pole lug is also in a curved state, and the like.

[0148] It should be further noted that the first bending part 32 and the first connecting piece 20, and the second bending part and the second connecting piece are connected by welding.

[0149] In order to reduce the possibility of welding to the diaphragm during welding, the number of overlaps of the first bending part 32 and the number of overlaps of the second bending part can be more.

[0150] When the first bending part 32 overlaps more than a certain number of times, the possibility of welding energy passing through the first bending part 32 and then reaching the diaphragm can be reduced.

[0151] When the second bending part overlaps more than a certain number of times, the possibility of welding energy passing through the second bending part and reaching the diaphragm can be reduced.

[0152] The first bending part 32 and the second bending part overlap more than or equal to 15 times.

[0153] Specifically, the winding number can be controlled so that the number of flat sections 11 on one side of the winding center 101 of the battery cell 100 is large, and the first bending part 32 and the second bending part overlap more times.

[0154] In some embodiments, in the extension direction of the winding center 101, the first tab 30 and the second tab are located on opposite sides of the battery cell 100.

[0155] Through the above arrangement, the first tab 30 and the second tab can be located on opposite sides of the battery cell.

[0156] When the battery cell is subsequently assembled into a prismatic battery 200, the first tab 30 and the second tab can be located on opposite sides of the prismatic battery 200, respectively, which can facilitate subsequent separate welding of the first tab 30 and the second tab, and reduce the possibility of mutual influence or even direct contact between the first tab 30 and the second tab during welding, which can cause short circuit.

[0157] In the embodiments of the present application, whether the first tab 30 is bent to form the first bending part 32 or the first bending part 32 is connected to the first connecting piece 20, the possibility of the tab being inserted upside down and piercing the first tab 10 can be reduced, which can improve the performance of the battery cell 100 and the prismatic battery 200 equipped with the battery cell 100, and reduce the possibility of short circuit and other safety problems in the prismatic battery 200.

[0158] Finally, it should be noted that the above embodiments are merely specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An electric core having a winding center, characterized by, The first tab includes a first connecting portion and a first bending portion connected with each other, the first connecting portion is connected with the flat segment, and each first bending portion is bent towards the winding center; The first connecting portion and the first bending portion of each first tab are connected with the first connecting sheet, a first included angle a is formed between the first connecting portion and the first bending portion, and the first included angle a satisfies 90°≤a≤160°. In the distribution direction of the plurality of flat segments, the first bending portion of any adjacent first tab among the first tabs with the same bending direction has an overlapping portion.

2. The electric cell of claim 1, wherein, In the distribution direction of the plurality of flat segments, the length of the first bending portion of the first tab close to the winding center is smaller than the length of the first bending portion of the first tab away from the winding center among the first tabs with the same bending direction.

3. The electric cell of claim 2, wherein, The length of the first bending portion is the distance between the opposite ends of the first bending portion in the distribution direction of the plurality of flat segments. The first connecting sheet has opposite first and second surfaces, the second surface is convex in the direction away from the first surface, and the second surface is connected with the plurality of first bending portions.

4. The electric cell of claim 2, wherein, In the direction from the winding center of the battery cell to the outside of the battery cell, the second surface has opposite first and second ends, and the second surface also has a top end opposite to the winding center.

5. The electric cell of claim 4, wherein, The first end and the first surface have a first distance L1, the second end and the first surface have a second distance L2, and the top end and the first surface have a third distance L3. L1, L2 and L3 satisfy L1≤L3 and L2≤L3. The connecting position of the first connecting portion and the first bending portion forms a bending position, and in the direction from the winding center of the battery cell to the outside of the battery cell, the bending position of the first tab close to the winding center is flush with the bending position of the first tab away from the winding center among any adjacent two first tabs.

6. The electric cell of claim 1, wherein, The battery cell also includes a separator, a second tab, a second connecting sheet and a plurality of second tabs, the plurality of second tabs are connected to the second tab, the separator is located between the second tab and the first tab, and the first tab and the second tab are wound to form the battery cell; 7. The electric cell of claim 1, wherein, The second tab includes a second connecting portion and a second bending portion connected with each other, the second connecting portion is connected with the second tab, and each second bending portion is bent towards the winding center, and the second bending portion of the plurality of second tabs is connected with the second connecting sheet. In the extension direction of the winding center, the first tab and the second tab are located on opposite sides of the battery cell.

8. The electric cell of claim 7, wherein, The first tab also includes a transition segment connected with two adjacent flat segments, the plurality of flat segments are parallel to each other, the transition segment is bent in the direction away from the flat segment connected therewith, and the plurality of transition segments are distributed on opposite sides of the battery cell; 9. The electric cell of claim 1, wherein, ​ In a distribution direction of the plurality of transition sections, the flat section has one end and another end opposite to the one end, and the first tab on one of the flat sections extends from the one end of the flat section to the another end of the flat section.

10. A prismatic battery, characterized by An electric device comprising the electric cell of any one of claims 1-9.

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