Battery cell, battery, and electric device

Abstract

The utility model discloses a kind of electric core, battery and electric equipment, electric core includes the first pole piece of winding arrangement, second pole piece, first isolation film and second isolation film, first isolation film is more close to the inner layer of winding structure relative to second isolation film, winding structure includes straight area and two bending areas respectively located in the both sides of straight area, winding start of first isolation film is first winding start, winding start of second isolation film is second winding start, second winding start does not protrude to first isolation film, first isolation film first bending section is first bending section, and bending area including first bending section is first bending area;First bending section includes first winding start;Or, first winding start is located in straight area, and more close to first bending area, i.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0002] In recent years, the lithium-ion battery manufacturing industry has developed rapidly, leading to increasingly stringent requirements for the automated feeding and winding processes of lithium battery separators. The separator is one of the key internal components of a rechargeable battery, positioned between the anode and cathode plates to prevent short circuits while allowing ions to pass through. In existing technologies, the separator is typically positioned in the flat area of ​​the battery cell. During processing, the interaction force between the winding needle and the separator causes a certain amount of tension when the needle is withdrawn. Due to the winding process, the flat area of ​​the cell is relatively loose, providing space for the separator to deform. Therefore, when the needle is withdrawn, the separator is prone to wrinkling due to the tension, posing a safety risk to the battery. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery cell that can be used in batteries to improve battery safety.

[0004] This utility model also provides a battery including the above-mentioned battery cell.

[0005] This utility model also provides an electrical device that includes the above-mentioned battery.

[0006] The battery cell according to a first aspect of the present invention includes: a first electrode, a second electrode, a first separator, and a second separator.

[0007] A first separator, a first electrode, a second separator, and a second electrode are stacked and wound together to form a wound structure. The first separator and the second separator separate the first electrode and the second electrode, and the first separator is closer to the inner layer of the wound structure than the second separator. The wound structure includes a straight region and two bending regions located on both sides of the straight region. The winding start end of the first separator is the first winding start end, and the winding start end of the second separator is the second winding start end. In the winding direction of the wound structure, the second winding start end does not protrude from the first separator. Along the winding direction of the wound structure, the first bending segment of the first separator is the first bending segment. One of the bending regions includes the first bending segment, and the bending region including the first bending segment is defined as the first bending region. The first bending segment includes the first winding start end. Alternatively, the first winding start end is located in the straight region and along the direction in which the two bending regions face each other, and in the two bending regions, the first winding start end is closer to the first bending region.

[0008] The battery cell according to the embodiments of this utility model has at least the following beneficial effects:

[0009] In this embodiment, the first separator is closer to the inner side of the battery cell than the second separator, and in the winding direction of the winding structure, the starting end of the second separator is located within the range of the first separator. The first bending section includes the first winding starting end, i.e., the first winding starting end is located in the bending area. Alternatively, the first winding starting section is located in the straight area, and along the direction in which the two bending areas face each other, the first winding starting end is closer to the first bending area, i.e., the first winding starting end extends out of the first bending area but is close to it. Since the bending area corresponds to the fulcrum where the first separator bends on the winding needle in the winding process, the bending area of ​​the battery cell is more compact than the straight area. That is, for the first separator, its winding starting end is fixed in the bending area. Therefore, during the removal of the winding needle, the risk of the first separator being pulled away by the winding needle can be reduced, i.e., the risk of wrinkles in the first separator during processing can be reduced. Furthermore, since the second separator does not directly contact the winding needle, the risk of wrinkling in the second separator is even lower than the risk of wrinkling in the first separator. Therefore, when the cell of this embodiment is used in a battery, battery safety can be improved.

[0010] According to some embodiments of the present invention, the second winding starting end is located in any of the bending areas.

[0011] According to some embodiments of the present invention, the first bending segment includes the first winding starting end;

[0012] The bending region includes a first end and a second end arranged sequentially along the winding direction of the winding structure. In the winding direction of the winding structure, the first winding start end is closer to the first end of the first bending region.

[0013] According to some embodiments of the present invention, the first electrode includes a first straight section located in the straight region, the winding start end of the first electrode is a third winding start end, the innermost first straight section includes the third winding start end, and the third winding start end faces the first bending region.

[0014] The first winding start end is located in the straight area, and in the direction in which the two bending areas face each other, the first winding start end is located between the third winding start end and the first bending area.

[0015] According to some embodiments of the present invention, the first electrode includes a first active material, and the first straight section of the innermost layer is provided with the first active material on both sides in its thickness direction.

[0016] The second electrode includes a fourth straight segment located in the straight region. The second electrode includes a second active material. The second active material is disposed on both sides of the innermost fourth straight segment in its thickness direction. The winding start end of the second electrode is the fourth winding start end. The innermost fourth straight segment includes the fourth winding start end. The third winding start end and the fourth winding start end face opposite directions. The innermost fourth straight segment is located between the innermost first straight segment and the next innermost first straight segment.

[0017] According to some embodiments of the present invention, there is a first isolation membrane between the innermost first straight segment and the innermost fourth straight segment.

[0018] According to some embodiments of the present invention, and along the direction in which the two bending areas face each other, the size of the straight area is L1, the size of the innermost first straight segment is L2, the size of the innermost fourth straight segment is L3, 0.2mm≤L2-L1≤5mm; and / or, 0.2mm≤L3-L1≤5mm.

[0019] According to some embodiments of the present invention, the first corner is bonded to the first bending area.

[0020] The battery according to a second aspect embodiment of the present invention includes the battery cell of the first aspect embodiment.

[0021] The battery according to the embodiments of the present invention has at least the following beneficial effects:

[0022] The battery cell of the first aspect embodiment has a lower risk of wrinkling of the first and second separators, thereby improving the safety of the battery of this embodiment.

[0023] The electrical device according to a third aspect embodiment of the present invention includes the battery of the second aspect embodiment.

[0024] The electrical equipment according to the embodiments of this utility model has at least the following beneficial effects:

[0025] The battery using the third aspect embodiment has higher safety, thereby improving the safety of the battery in this example.

[0026] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0028] Figure 1 This is a schematic diagram of the structure of the first type of battery cell according to the first aspect of this utility model;

[0029] Figure 2 This is a schematic diagram of the structure of the second type of battery cell according to the first aspect of this utility model;

[0030] Figure 3 This is a schematic diagram of the structure of the third type of battery cell according to the first aspect of this utility model;

[0031] Figure 4 This is a schematic diagram of the structure of the fourth type of battery cell according to the first aspect of this utility model;

[0032] Figure 5 This is a schematic diagram of the structure of the fifth type of battery cell according to the first aspect of this utility model.

[0033] Figure label:

[0034] Straight area 1000, bending area 2000, first bending area 2000a, first end 2100, second end 2200;

[0035] First electrode 100, first straight section 110, innermost first straight section 111, next innermost first straight section 112, third winding start end 120, first active material 130.

[0036] Second electrode 200, fourth straight section 210, innermost fourth straight section 211, fourth winding start end 220, second active material 230;

[0037] First separating membrane 300, first winding start end 310, second straight section 320, innermost second straight section 321, next innermost second straight section 322, first curved section 330;

[0038] Second separator 400, second winding start end 410, third straight section 420, innermost third straight section 421, next innermost third straight section 422, second curved section 430. Detailed Implementation

[0039] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0040] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0041] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0042] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0043] In recent years, the lithium-ion battery manufacturing industry has developed rapidly, leading to increasingly stringent requirements for the automated feeding and winding processes of lithium battery separators. The separator is one of the key internal components of a rechargeable battery, positioned between the anode and cathode plates to prevent short circuits while allowing ions to pass through. In existing technologies, the separator is typically positioned in the flat area of ​​the battery cell. During processing, the interaction force between the winding needle and the separator causes a certain amount of tension when the needle is withdrawn. Due to the winding process, the flat area of ​​the cell is relatively loose, providing space for the separator to deform. Therefore, when the needle is withdrawn, the separator is prone to wrinkling due to the tension, posing a safety risk to the battery.

[0044] In view of the above background, the first aspect of this utility model provides a battery cell that can be used in a battery to improve battery safety. (See also...) Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of the first type of battery cell according to the first aspect of this utility model. Figure 2 This is a schematic diagram of the structure of the second type of battery cell according to the first aspect of this utility model. Figure 2 The center line in the middle is the dividing line between the straight area 1000 and the bending area 2000. The battery cell in this embodiment includes a first electrode 100, a second electrode 200, a first separator 300 and a second separator 400.

[0045] In this structure, the first electrode 100 is, for example, an anode, and the second electrode 200 is, for example, a cathode. The first separator 300, the first electrode 100, the second separator 400, and the second electrode 200 are stacked and wound together to form a wound structure. The first separator 300 and the second separator 400 separate the first electrode 100 and the second electrode 200, with the first separator 300 being closer to the inner layer of the wound structure than the second separator 400. The wound structure includes a straight region 1000 and two bent regions 2000 located on either side of the straight region 1000. The winding start end of the first separator 300 is a first winding start end 310, and the winding start end of the second separator 400 is a second winding start end 410. In the winding direction of the wound structure, the second winding start end 410 does not protrude from the first separator 300. For example, the second winding start end 410 is flush with the first winding start end 310, or the second winding start end 410 is located between the first winding start end 310 and the end of the first electrode 100 (e.g. Figure 1As shown), during the winding process, the winding needle only contacts the first release film 300. That is, when the winding needle is pulled out, it only directly pulls the first release film 300. Along the winding direction of the winding structure, the first curved section of the first release film 300 is the first curved section 330, and a bending region 2000 includes the first curved section 330. The bending region 2000 including the first curved section 330 is defined as the first bending region 2000a. The first curved section 330 includes the first winding start end 310, that is, the first winding start end 310 is located in the bending region 2000 (e.g., as shown). Figure 1 (As shown). Alternatively, the first winding start end 310 is located in the flat region 1000, and along the direction in which the two bending regions 2000 face each other (the width direction of the cell in the figure), of the two bending regions 2000, the first winding start end 310 is closer to the first bending region 2000a (as shown). Figure 2 As shown), the first winding start end 310 extends out of the first bending area 2000a, but is close to the first bending area 2000a. For example, the distance between the first winding start end 310 and the first bending area 2000a is 2mm.

[0046] Specifically, during the winding process, the first electrode 100, the second electrode 200, the first separator 300, and the second separator 400 need to adapt to the bending path of the winding machine in the bending zone 2000. That is, the bending zone 2000 corresponds to the fulcrum where the first separator 300 bends on the winding needle. Therefore, the tension of the first separator 300 is greater in the bending zone 2000, making the bending zone 2000 of the battery cell more compact than the straight zone 1000. Therefore, the starting end of the winding of the first separator 300 is set in the bending zone 2000 of the battery cell, and the starting end of the winding of the first separator 300 is fixed in the bending zone 2000, thereby reducing the risk of wrinkling of the first separator 300 when the winding needle is withdrawn. Meanwhile, since the second separator 400 does not directly contact the winding needle, the risk of wrinkling of the second separator 400 mainly arises from the pulling between it and the first separator 300. Therefore, in this embodiment, the risk of wrinkling in the first separator 300 is lower, and the risk of wrinkling in the second separator 400 is also lower. Thus, when the cell of this embodiment is used in a battery, battery safety can be improved.

[0047] It should be noted that, in this embodiment, the starting end of the winding of the second separator 400 is located in the bending region 2000, but is not limited thereto. Since it does not directly contact the winding needle during the winding process, the starting end of the winding of the second separator 400 can also be located in the straight region 1000 (e.g., Figure 1 (As shown). Preferably, the second winding start end 410 is also located in the bending region 2000, but is not limited to being located in the same bending region 2000 as the first winding start end 310. The fact that the second winding start end 410 is located in the bending region 2000 can further reduce the risk of wrinkles in the second separator 400.

[0048] Reference Figure 2 In the above embodiment, the bending region 2000 includes a first end 2100 and a second end 2200 arranged sequentially along the winding direction of the winding structure. In the winding direction of the winding structure, the first winding starting end 310 is closer to the first end 2100 of the bending region 2000 where it is located, that is, the first winding starting end 310 is closer to the first bending region 2000a. The length S1 of the innermost part of the first separator 300 located in the first bending region 2000a is S2 of the corresponding length of the innermost electrode (first electrode 100 or second electrode 200) in the first bending region 2000a. 0.8≤S1 / S2≤1, thereby increasing the degree of bending of the winding starting section of the first separator 300. Therefore, when subjected to a force along the width direction of the first separator 300 (that is, the length direction of the cell), the shape of the winding starting section is more difficult to change, further reducing the risk of wrinkles in the first separator 300. Meanwhile, the first separator 300 is extended to the first end 2100 near the bending area 2000 to prevent the first winding start end 310 from moving to the flat area 1000 due to the shrinkage of the first separator 300 during the winding process, thereby improving the safety of the battery.

[0049] Reference Figure 3 , Figure 3This is a schematic diagram of the structure of a third type of battery cell according to the first aspect of this utility model. In some embodiments, the first electrode 100 includes a first straight section 110 located in the straight region 1000, and the innermost first straight section 111 includes the winding start end of the first electrode 100. The winding start end of the first electrode 100 is called the third winding start end 120. The third winding start end 120 faces the first bending region 2000a. The first winding start end 310 is located in the straight region 1000 and along the direction in which the two bending regions 2000 face each other, the first winding start end 310 is located between the third winding start end 120 and the first bending region 2000a to reduce the thickness of the battery. Specifically, the first separator 300 includes a second straight section 320 located in the straight region 1000. The innermost second straight section 321 includes a first winding start end 310, which is located between the third winding start end 120 and the first bending region 2000a. That is, the innermost second straight section 321 is located between the innermost first straight section 111 and the first bending region 2000a, so that the innermost second straight section 321 and the innermost first straight section 111 are offset in the thickness direction of the battery cell. Therefore, after winding, the first separator 300 can be deformed by applying pressure to the battery cell, so that the innermost second straight section 321 does not need to occupy additional space in the thickness direction of the battery cell, thereby reducing the thickness of the battery cell and increasing the energy density. Similarly, in some embodiments, the second separator 400 includes a third straight section 420 located in the straight region 1000, and the innermost third straight section 421 includes a second winding start end 410. The orientation of the second winding start end 410 is opposite to that of the third winding start end 120, and the second winding start end 410 is located between the third winding start end 120 and the first bending region 2000a, so that the innermost third straight section 421 does not need to occupy additional space in the thickness direction of the battery cell.

[0050] Reference Figure 4 , Figure 4This is a schematic diagram of the structure of a fourth type of battery cell according to the first aspect of this utility model. In some embodiments, the first electrode 100 includes a first active material 130, and the innermost first straight section 111 has the first active material 130 disposed on both sides in its thickness direction. The second electrode 200 includes a fourth straight section 210 located in the straight region 1000, and the second electrode 200 includes a second active material 230, and the innermost fourth straight section 211 has the second active material 230 disposed on both sides in its thickness direction. The innermost fourth straight section 211 includes the winding start end of the second electrode 200, which is the fourth winding start end 220. The fourth winding start end 220 faces away from the third winding start end 120. The innermost fourth straight section 211 is located between the innermost first straight section 111 and the next innermost first straight section 112. The next innermost first straight section 112 is the second first straight section 110 along the winding direction of the winding structure. That is, in this embodiment, the heads (winding start sections) of the first electrode 100 and the second electrode 200 are in a paired structure, and there is no empty foil area at the head, making greater use of the foil material of the first electrode 100 and the second electrode 200, thereby improving the energy density of the battery.

[0051] Reference Figure 4 and Figure 5 , Figure 5 The schematic diagram of the fifth type of battery cell according to the first aspect of this utility model is as follows: Based on the above embodiment, there is only one first insulating film 300 between the innermost first straight segment 111 and the innermost fourth straight segment 211. Since the second winding starting end 410 does not protrude from the first insulating film 300, there is only one first insulating film 300 between the innermost first straight segment 111 and the innermost fourth straight segment 211, and no second insulating film 400 is provided, thereby reducing the obstruction of ion transport and reducing the impedance of the battery cell. Specifically, as shown in the figure... Figure 4 As shown, the innermost first straight segment 111 is located between the second straight segment 322 and the third straight segment 422 of the next innermost layer. That is, the first winding start end 310 is located in the innermost second straight segment 321, the second winding start end 410 is located in the innermost third straight segment 421, and both the innermost second straight segment 321 and the innermost third straight segment 421 are located between the third winding start end 120 and the first bending area 2000a. This ensures that the area directly opposite the innermost first straight segment 111 and the innermost fourth straight segment 211 is only provided with the second straight segment 322 of the next innermost layer. Alternatively, as... Figure 5As shown, the first winding start end 310 and the second winding start end 410 are both located in the same bending area 2000 (first bending area 2000a). The innermost first straight segment 111 is located between the innermost second straight segment 321 and the innermost third straight segment 421. That is, the innermost second straight segment 321 is provided between the innermost first straight segment 111 and the innermost fourth straight segment 211.

[0052] Reference Figure 4 , Figure 4 This is a schematic diagram of the structure of a fourth type of battery cell according to the first aspect of this utility model. In some embodiments, along the direction in which the two bending areas face each other, that is, corresponding to the width direction of the battery cell in the figure, the size of the straight area 1000 is L1, the size of the innermost first straight segment 111 is L2, and the size of the innermost fourth straight segment 211 is L3, with 0.2mm ≤ L2 - L1 ≤ 5mm. Specifically, it can be understood that during battery operation, the temperature inside the battery cell is higher than the temperature at the edge, resulting in a certain difference between the expansion inside and outside the battery cell. Due to the greater temperature change inside, the expansion of the inner electrode is greater. That is, the expansion of the innermost first straight segment 111 of the first electrode 100 is greater than that of the outer layer. If the starting end of the first electrode 100 extends into the bending area 2000, due to the rigidity of the first electrode 100 itself, the third winding starting end 120 will press against the second separator 400, increasing the risk of the second separator 400 being cut.

[0053] This embodiment effectively improves the above-mentioned problems. In this embodiment, 0.2mm ≤ L2-L1 ≤ 5mm, meaning the third winding start end 120 is spaced apart from the second end 2200 of the bending region 2000. Therefore, even if the innermost first straight section 111 expands more than the outermost first straight section 110, the third winding start end 120 can still be located outside the bending region 2000, thereby reducing the risk of the second separator 400 being cut and improving battery safety. Of course, if the size of the first straight section 110 is too small, it will result in less first active material 130 and reduce battery capacity. Therefore, in this embodiment, 0.2mm ≤ L2-L1 ≤ 5mm keeps the size of the first straight section 110 within a suitable range, thereby improving battery safety while ensuring battery capacity. Similarly, in some embodiments, 0.2mm ≤ L3-L1 ≤ 5mm is used to reduce the extension of the second electrode 200's winding start end into the bending region 2000, which will not be elaborated here.

[0054] Reference Figure 4In some embodiments, the first bent segment 330 is bonded to the first bending region 2000a. For example, the first bent segment 330 is bonded to the second electrode 200 located in the first bending region 2000a by an adhesive 500 or adhesive tape. However, this is not the only embodiment. In some embodiments, the winding structure has a first electrode 100 pre-wound one turn. That is, during the winding process, the first electrode 100 is wound one turn first, and then the second electrode 200 is wound synchronously. Thus, the first electrode 100 is close to the first bent segment 330 in the first bending region 2000a. By bonding the first bent segment 330 to the first bending region 2000a, the stability of the first separator 300 can be improved, thereby reducing the risk of the first separator 300 wrinkling due to the pulling of the winding needle. Further, in some embodiments, the second bent segment 430 of the second separator 400 (the first bent segment of the second separator 400 along the winding direction of the winding structure) is bonded to the first bending region 2000a.

[0055] It should be noted that in the above embodiment, "innermost layer" refers to the first layer in the winding process, and "second innermost layer" refers to the second layer in the winding process. The innermost second straight section 321 and the second innermost second straight section 322 are used as examples. The innermost second straight section 321 is the first straight section of the first separator 300 in the winding process, and the second innermost second straight section 322 is the second straight section of the first separator 300 in the winding process. The innermost second straight section 321 and the second innermost second straight section 322 are connected by a curved section. For example, when the first winding start end 310 is located at the innermost second straight section 321, the innermost second straight section 321 and the second innermost second straight section 322 are connected by a first curved section 330.

[0056] The battery of the second aspect embodiment of this utility model is, for example, a pouch battery, a steel-cased battery, or an aluminum-cased battery. The battery includes the cell of the above embodiment. The first separator 300 and the second separator 400 in the cell have a lower risk of wrinkling, thereby improving the safety of the battery of this embodiment.

[0057] It should be noted that since this embodiment adopts all the technical features of the battery cell in the above embodiments, this embodiment has all the beneficial effects brought by the battery cell in the above embodiments, which will not be repeated here.

[0058] The electrical device of the third aspect embodiment of this utility model is, for example, a watch, a bracelet, a mobile phone, a tablet, or a new energy vehicle. The electrical device includes the battery of the second aspect embodiment, which has higher safety, thereby improving the safety of the battery in this example.

[0059] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, in the description of the present invention, the reference to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A battery cell, characterized in that, include: First electrode plate; Second electrode; First separating membrane; The second separator is formed by stacking and winding the first separator, the first electrode, the second separator, and the second electrode together to form a winding structure. The first separator and the second separator separate the first electrode and the second electrode, and the first separator is closer to the inner layer of the winding structure than the second separator. The winding structure includes a straight region and two bending regions located on both sides of the straight region. The winding start end of the first separator is the first winding start end, and the winding start end of the second separator is the second winding start end. In the winding direction of the winding structure, the second winding start end does not protrude from the first separator. Along the winding direction of the winding structure, the first bending segment of the first separator is the first bending segment. One of the bending regions includes the first bending segment. The bending region including the first bending segment is defined as the first bending region. Wherein, the first curved segment includes the first winding start end; or, The first winding start end is located in the straight area and along the direction in which the two bending areas face each other. Of the two bending areas, the first winding start end is closer to the first bending area.

2. The battery cell according to claim 1, characterized in that, The second winding start end is located in any of the bending areas.

3. The battery cell according to claim 1, characterized in that, The first curved section includes the first winding start end; The bending region includes a first end and a second end arranged sequentially along the winding direction of the winding structure. In the winding direction of the winding structure, the first winding start end is closer to the first end of the first bending region.

4. The battery cell according to claim 1, characterized in that, The first electrode includes a first straight section located in the straight region, the first electrode has a third winding start end, the innermost first straight section includes the third winding start end, and the third winding start end faces the first bending region. The first winding start end is located in the straight area, and in the direction in which the two bending areas face each other, the first winding start end is located between the third winding start end and the first bending area.

5. The battery cell according to claim 4, characterized in that, The first electrode includes a first active material, and the first straight section of the innermost layer is provided with the first active material on both sides in its thickness direction; The second electrode includes a fourth straight segment located in the straight region. The second electrode includes a second active material. The second active material is disposed on both sides of the innermost fourth straight segment in its thickness direction. The winding start end of the second electrode is the fourth winding start end. The innermost fourth straight segment includes the fourth winding start end. The third winding start end and the fourth winding start end face opposite directions. The innermost fourth straight segment is located between the innermost first straight segment and the next innermost first straight segment.

6. The battery cell according to claim 5, characterized in that, There is only one layer of the first isolation membrane between the first straight section of the innermost layer and the fourth straight section of the innermost layer.

7. The battery cell according to claim 5, characterized in that, And along the direction in which the two bending areas face each other, the size of the straight area is L1, the size of the innermost first straight segment is L2, the size of the innermost fourth straight segment is L3, 0.2mm≤L2-L1≤5mm; and / or, 0.2mm≤L3-L1≤5mm.

8. The battery cell according to claim 1, characterized in that, The first curved segment is bonded to the first bending area.

9. A battery, characterized in that, The battery cell includes any one of claims 1 to 8.

10. Electrical equipment, characterized in that, Includes the battery as described in claim 9.

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