Roll core assembly, roll core unit, battery and electronic equipment

Abstract

The utility model discloses a roll core assembly, roll core unit, battery and electronic equipment, roll core assembly includes: roll core body, roll core body has positive pole piece, diaphragm and negative pole piece, diaphragm separates positive pole piece and negative pole piece, the end of positive pole piece is equipped with the first leading-out foil that extends along its length direction, and the end of negative pole piece is equipped with the second leading-out foil that extends along its length direction. A second leading-out foil extending in the length direction is arranged at the ending end of the negative plate, and the second leading-out foil and the first leading-out foil are staggered in position; the first tab is used for being connected with the first lead-out foil, and the second tab is used for being connected with the second lead-out foil. According to the roll core assembly disclosed by the utility model, the roll core body, the first tab and the second tab are arranged, so that the positive plate and the negative plate can be connected with the first tab and the second tab after being wound to form the roll core body, and the positions of the first tab and the second tab can be accurately controlled; the problem of poor battery packaging caused by large deviation of the mounting position of the tab is effectively avoided, and the packaging quality of the battery is improved.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology, specifically relating to a winding assembly, winding unit, battery, and electronic device. Background Technology

[0002] In related technologies, during the fabrication of battery core units, the positive and negative tabs are typically welded to the positive and negative electrode sheets before they are wound into a core. This method, due to factors such as the winding operation, is prone to significant positional deviations of the positive and negative tabs, leading to problems such as poor battery encapsulation and consequently affecting battery quality.

[0003] Therefore, a new technical solution is needed to solve the above-mentioned technical problems. Utility Model Content

[0004] The first objective of this invention is to provide a new technical solution for a core assembly.

[0005] The second objective of this invention is to provide a new technical solution for a core unit.

[0006] The third objective of this invention is to provide a new technical solution for batteries.

[0007] The fourth objective of this invention is to provide a new technical solution for an electronic device.

[0008] According to a first aspect of the present invention, a winding core assembly is provided, comprising: a winding core body having a positive electrode sheet, a separator, and a negative electrode sheet, the separator separating the positive electrode sheet and the negative electrode sheet, the positive electrode sheet having a first lead foil extending along its length at its terminal end, and the negative electrode sheet having a second lead foil extending along its length at its terminal end, the second lead foil being offset from the first lead foil; a first electrode tab and a second electrode tab, the first electrode tab being used to connect with the first lead foil, and the second electrode tab being used to connect with the second lead foil.

[0009] Optionally, the winding core assembly further includes an insulating connector, wherein both the first tab and the second tab are disposed on the insulating connector.

[0010] Optionally, the diaphragm bonds the positive electrode and the negative electrode.

[0011] Optionally, the diaphragm is configured as a bag, which is fitted over the positive electrode or the negative electrode.

[0012] Optionally, a first empty foil area is provided on one side of the positive electrode, and the position of the first empty foil area corresponds to the starting end of the negative electrode.

[0013] Optionally, the negative electrode sheet has a negative electrode starting segment, which includes a first sub-segment, a bending segment, and a second sub-segment connected in sequence.

[0014] The first sub-segment and the second sub-segment are stacked, and the side of the first sub-segment and the second sub-segment that are close to each other, as well as the inner side of the bent segment, are configured as the second empty foil area.

[0015] Optionally, the outer side of the positive or negative electrode sheet located on the outer ring of the core body is configured as a third empty foil area, and the third empty foil area is provided with an insulating layer.

[0016] According to a second aspect of the present invention, a core unit is provided, comprising: a core assembly as described in any of the preceding claims, wherein a first tab is welded to a first lead-out foil, a second tab is welded to a second lead-out foil, and the first tab and the second tab extend from the side of the core body; and insulating adhesive paper, wherein the insulating adhesive paper is adhered to the first lead-out foil and the second lead-out foil, and to the connection between the first tab and the first lead-out foil and the connection between the second tab and the second lead-out foil.

[0017] Optionally, the core body is configured as a curved flat core or a straight flat core.

[0018] Optionally, the first lead foil and the second lead foil are led out from one side of the length direction of the core body. The first lead foil has one or more first bends so that the connection between the first lead foil and the first tab is located on one side of the core body in its thickness direction. The second lead foil has one or more second bends so that the connection between the second lead foil and the second tab is located on one side of the core body in its thickness direction. In the length direction of the core body, the tail ends of the first tab and the second tab are away from the core body.

[0019] Optionally, the core body has an inner arc side and an outer arc side that are disposed opposite to each other in its thickness direction, and the first lead foil and the second lead foil are located on the outer arc side of the core body.

[0020] According to a third aspect of the present invention, a battery is provided, comprising the winding unit described in any of the preceding claims.

[0021] According to a fourth aspect of the present invention, an electronic device is provided, comprising the aforementioned battery.

[0022] According to the present invention, the core assembly, by setting a core body, a first tab, and a second tab, allows the positive and negative electrode sheets to be connected to the first and second tabs after being wound to form the core body. This allows for precise control of the positions of the first and second tabs, effectively avoiding problems such as poor battery encapsulation caused by large deviations in the tab installation positions, and improving the battery encapsulation quality. Moreover, the core body can be prepared using automated winding equipment, ensuring battery production efficiency.

[0023] Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present invention and, together with their description, serve to explain the principles of the present invention.

[0025] Figure 1 This is a schematic diagram of the structure of a core assembly according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a core assembly according to another embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the positive electrode sheet of a winding core assembly according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the negative electrode sheet of a winding core assembly according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the positive and negative electrode sheets of the winding core assembly according to an embodiment of the present invention when it is not wound.

[0030] Figure 6 This is a schematic diagram of the structure of the starting segment of the negative electrode sheet of the core assembly according to another embodiment of the present invention when it is not bent.

[0031] Figure 7 This is a schematic diagram of the structure of the starting segment of the negative electrode sheet of the core assembly according to another embodiment of the present invention after bending.

[0032] Figure 8 This is a schematic diagram of the structure of the first and second lead foils of the core unit according to an embodiment of the present invention when they are not bent.

[0033] Figure 9 This is a schematic diagram of the structure of a core unit according to an embodiment of the present invention;

[0034] Figure 10 This is a schematic diagram of the structure of the core body after welding with the first and second pole tabs according to another embodiment of the present invention;

[0035] Figure 11 This is a schematic diagram of the structure of the first and second lead foils of the core unit according to another embodiment of the present invention when they are not bent;

[0036] Figure 12 This is a schematic diagram of the core unit according to another embodiment of the present invention.

[0037] Figure label:

[0038] 100. Core unit;

[0039] 10. Core body; 11. Positive electrode sheet; 111. First lead foil; 112. First empty foil area; 12. Separator; 13. Negative electrode sheet; 131. Second lead foil; 132. First sub-segment; 133. Bending segment; 134. Second sub-segment; 135. Second empty foil area; 136. Insulating layer;

[0040] 20. First tab; 30. Second tab; 40. Insulating connector; 50. Insulating tape. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0042] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0043] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0044] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0046] The core assembly according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0047] like Figures 1 to 7 As shown, the core assembly according to an embodiment of the present invention includes: a core body 10, a first tab 20, and a second tab 30.

[0048] Specifically, the core body 10 has a positive electrode 11, a separator 12, and a negative electrode 13. The separator 12 separates the positive electrode 11 and the negative electrode 13. The end of the positive electrode 11 is provided with a first lead foil 111 extending along its length direction. The end of the negative electrode 13 is provided with a second lead foil 131 extending along its length direction. The second lead foil 131 is offset from the first lead foil 111. A first tab 20 is used to connect with the first lead foil 111, and a second tab 30 is used to connect with the second lead foil 131.

[0049] In other words, such as Figures 1 to 7 As shown, the core assembly according to this embodiment of the present invention mainly consists of a core body 10, a first tab 20, and a second tab 30. The core body 10 includes a positive electrode sheet 11, a separator 12, and a negative electrode sheet 13, all of which are elongated structures. During the preparation of the core body 10, the positive electrode sheet 11 and the negative electrode sheet 13 are stacked, with the separator 12 separating them. The positive electrode sheet 11, the separator 12, and the negative electrode sheet 13 have the same length direction, and are stacked to form a core preform. When winding the core body 10, the core preform is simply wound along its length direction to obtain the core body 10.

[0050] Specifically, the positive electrode 11 has a first lead-out foil 111 extending along its length (i.e., a negative electrode current collector without negative electrode active material in the thickness direction) at its end, so that the first lead-out foil 111 is led out from the side of the core body 10. The negative electrode 13 has a second lead-out foil 131 extending along its length (i.e., a positive electrode current collector without positive electrode active material in the thickness direction) at its end, so that the second lead-out foil 131 is led out from the side of the core body 10. The width of the first lead-out foil 111 and the second lead-out foil 131 is less than the height of the core body 10 (i.e., the width of the wound portion of the positive electrode 11 and the negative electrode 13), and the positions of the first lead-out foil 111 and the second lead-out foil 131 are staggered.

[0051] The first tab 20 is a positive tab, used to connect with the first lead foil 111. The second tab 30 is a positive tab, used to connect with the second lead foil 131. When manufacturing the core unit 100, connecting the first tab 20 to the first lead foil 111 of the core body 10 and connecting the second tab 30 to the second lead foil 131 of the core body 10 ensures the accuracy of the installation positions of the first tab 20 and the second tab 30.

[0052] Therefore, according to the embodiment of the present invention, by setting the core assembly 10, the first tab 20 and the second tab 30, the positive electrode 11 and the negative electrode 13 can be connected to the first tab 20 and the second tab 30 after being wound to form the core assembly 10. This allows for precise control of the positions of the first tab 20 and the second tab 30, effectively avoiding problems such as poor battery encapsulation caused by large deviations in the tab installation positions, and improving the battery encapsulation quality. Moreover, the core assembly 10 can be prepared using automated winding equipment, which can ensure the battery production efficiency.

[0053] According to one embodiment of the present invention, the core assembly further includes an insulating connector 40, wherein the first tab 20 and the second tab 30 are both disposed on the insulating connector 40.

[0054] Specifically, such as Figure 1 and Figure 2 As shown, the first electrode tab 20 includes a first connecting segment, a first intermediate segment, and a second connecting segment distributed along its length direction, and the second electrode tab 30 includes a third connecting segment, a second intermediate segment, and a fourth connecting segment distributed along its length direction. The first intermediate segment of the first electrode tab 20 and the second intermediate segment of the second electrode tab 30 are connected together by an insulating connector 40, while the first electrode tab 20 and the second electrode tab 30 maintain a certain distance in the width direction of the first electrode tab 20.

[0055] In this embodiment, the first electrode 20 and the second electrode 30 are connected as a whole by an insulating connector 40, and can be welded as a whole. This reduces the cumulative error that may occur when welding each electrode individually, and can ensure the accuracy of the position of the first electrode 20 and the second electrode 30.

[0056] In some specific embodiments of this utility model, the diaphragm 12 bonds the positive electrode 11 and the negative electrode 13.

[0057] In other words, the positive electrode 11 and the negative electrode 13 can be bonded together by the separator 12. For example, the separator 12 can be a polymer material. After the positive electrode 11 and the negative electrode 13 are wound, the wound structure is hot-pressed. During the hot-pressing process, the separator 12 will bond together with the positive electrode 11 and the negative electrode 13, so that it is not necessary to use adhesive tape to fix the end of the core body 10, which effectively simplifies the structure of the core body 10.

[0058] According to one embodiment of the present invention, the diaphragm 12 is configured as a bag, which is fitted onto the positive electrode 11 or the negative electrode 13.

[0059] Specifically, such as Figure 5 As shown, the diaphragm 12 is formed into a bag, which can be fitted onto the positive electrode 11 from the starting end of the positive electrode 11, or the bag can be fitted onto the negative electrode 13 from the starting end of the negative electrode 13.

[0060] In this embodiment, by configuring the separator 12 as a bag, the positive electrode 11 or the negative electrode 13 is completely covered in the separator 12 bag, which can effectively avoid the occurrence of short circuit problems and ensure the structure of the core body 10, which is beneficial for subsequent shaping.

[0061] In some specific embodiments of this utility model, a first empty foil area 112 is provided on one side of the positive electrode 11, and the position of the first empty foil area 112 corresponds to the starting end of the negative electrode 13.

[0062] In other words, such as Figure 5 As shown, the positive electrode 11 has a first empty foil area 112 (i.e., an area where no positive electrode active material is provided) on one side surface in the thickness direction. Since no positive electrode active material is provided in the first empty foil area 112, the positive electrode 11 forms a groove in this area. After the positive electrode 11 and the negative electrode 13 are wound together to form a core body 10, the position of the first empty foil area 112 (i.e., the groove) corresponds to the starting end of the negative electrode 13. The position of the negative current collector at the starting end of the negative electrode 13 corresponding to the position of the positive electrode 11 does not have positive electrode active material provided, thus effectively avoiding the generation of lithium plating problem.

[0063] According to one embodiment of the present invention, the negative electrode sheet 13 has a negative electrode starting segment, which includes a first sub-segment 132, a bending segment 133 and a second sub-segment 134 connected in sequence. The first sub-segment 132 and the second sub-segment 134 are stacked, and the side of the first sub-segment 132 and the second sub-segment 134 that are close to each other and the inner side of the bending segment 133 are configured as a second empty foil area 135.

[0064] Specifically, such as Figure 6 and Figure 7As shown, the negative electrode 13 includes a negative electrode starting segment, a middle segment, and a negative electrode ending segment connected sequentially along its length. The negative electrode starting segment includes a first sub-segment 132, a bending segment 133, and a second sub-segment 134 connected sequentially. The first sub-segment 132 and the second sub-segment 134 are stacked, so that the bending segment 133 serves as the starting end of the negative electrode 13. In this case, the entire starting end of the negative electrode 13 is covered by the negative electrode active material, which can effectively avoid the generation of lithium plating problem.

[0065] In addition, the side where the first sub-segment 132 and the second sub-segment 134 are close to each other and the inner side of the bent segment 133 are provided with negative electrode active material to form a second empty foil region 135. This is beneficial for the bending of the negative electrode starting segment and can avoid the thickness of the stacked position of the first sub-segment 132 and the second sub-segment 134 being too large.

[0066] In some optional examples of this utility model, the outer side of the negative electrode sheet 13 located on the outer ring of the core body 10 is configured as a third empty foil area, and the third empty foil area is provided with an insulating layer 136.

[0067] In other words, the core body 10 is a core structure with the negative electrode sheet 13 wrapped around its tail. The negative electrode sheet 13 is located on the outer ring of the core body 10. In this case, the outer side of the negative electrode sheet 13 located on the outer ring of the core body 10 is configured as a third empty foil area (i.e., the area where no negative electrode active material is provided), and the third empty foil area is covered with an insulating layer 136. This allows an insulating structure to be formed on the outer ring of the core body 10, which can achieve good insulation between the core body 10 and the packaging structure, effectively prevent internal short circuits in the battery, and effectively improve the safety performance of the battery.

[0068] In summary, the core assembly according to this utility model embodiment, by setting the core body 10, the first tab 20 and the second tab 30, allows the positive electrode 11 and the negative electrode 13 to be connected to the first tab 20 and the second tab 30 after being wound to form the core body 10. This allows for precise control of the positions of the first tab 20 and the second tab 30, effectively avoiding problems such as poor battery encapsulation caused by large deviations in the tab installation positions, and improving the battery encapsulation quality. Moreover, the core body can be prepared using automated winding equipment, which can ensure the battery production efficiency.

[0069] like Figures 8 to 12As shown, an embodiment of the present invention also provides a core unit 100, including the core assembly and insulating tape 50 described in any of the above embodiments. A first tab 20 is welded to a first lead-out foil 111, a second tab 30 is welded to a second lead-out foil 131, the first tab 20 and the second tab 30 are led out from the side of the core body 10, and the insulating tape 50 is adhered to the first lead-out foil 111 and the second lead-out foil 131, as well as the connection between the first tab 20 and the first lead-out foil 111 and the second tab 30 and the second lead-out foil 131.

[0070] like Figures 8 to 12 As shown, in other words, the core unit 100 according to the embodiment of the present invention mainly includes a core assembly and insulating tape 50, wherein the core assembly is the core assembly described in any of the above embodiments. When preparing the core unit 100, the first tab 20 is welded to a first or second side in the thickness direction of the first lead-out foil 111, and the second tab 30 is welded to a first or second side in the thickness direction of the second lead-out foil 131. After the first tab 20 and the second tab 30 are welded, the insulating tape 50 is adhered to the first lead-out foil 111 and the second lead-out foil 131, as well as the connection between the first tab 20 and the first lead-out foil 111 and the second tab 30 and the second lead-out foil 131, thus obtaining the desired core unit 100.

[0071] In this embodiment, the positive electrode 11 and the negative electrode 13 are connected to the first tab 20 and the second tab 30 after being wound to form the core body 10. This allows for precise control of the positions of the first tab 20 and the second tab 30, effectively avoiding battery encapsulation defects caused by large deviations in the tab installation positions and improving the battery encapsulation quality. Furthermore, the insulating tape 50 covers the first lead foil 111 and the second lead foil 131, as well as the connection between the first tab 20 and the first lead foil 111 and the second tab 30 and the second lead foil 131, ensuring battery safety.

[0072] In some specific embodiments of this utility model, the core body 10 is configured as a curved flat core or a straight flat core. When the core body 10 is a curved flat core, it can be applied to curved batteries; when the core body 10 is a curved straight flat core, it can be applied to prismatic batteries.

[0073] According to one embodiment of the present invention, a first lead-out foil 111 and a second lead-out foil 131 are led out from one side of the length direction of the core body 10. The first lead-out foil 111 has one or more first bends so that the connection between the first lead-out foil 111 and the first tab 20 is located on one side of the core body 10 in its thickness direction. The second lead-out foil 131 has one or more second bends so that the connection between the second lead-out foil 131 and the second tab 30 is located on one side of the core body 10 in its thickness direction. In the length direction of the core body 10, the tail ends of the first tab 20 and the second tab 30 are away from the core body 10.

[0074] Specifically, such as Figures 8 to 12 As shown, the core body 10 is a flat core. The first lead foil 111 and the second lead foil 131 extend from the core body 10 along its length from either a first or second side. The first connecting segment of the first tab 20 is welded to the first lead foil 111, and the third connecting segment of the second tab 30 is welded to the second lead foil 131. When welding the second tab 30 and the second lead foil 131, the tail end of the second tab 30 (i.e., the fourth connecting segment) is close to the core body 10 along its length. After welding, the first lead foil 111 and the second lead foil 131 can be bent once or multiple times, including but not limited to the following situations:

[0075] Scenario 1, such as Figure 8 and Figure 9 As shown, when the lengths of the first lead foil 111 and the second lead foil 131 are relatively short, the first lead foil 111 and the second lead foil 131 can be bent once. Specifically, when the first lead foil 111 and the second lead foil 131 are not bent, in the length direction of the core body 10, the tail end of the first tab 20 (i.e., the second connecting section) and the tail end of the second tab 30 (i.e., the fourth connecting section) are close to the core body 10, and the first lead foil 111 and the second lead foil 131 are located on the first side of the core body 10 in its thickness direction. When bending, the first lead foil 111 can be bent along the winding direction of the positive electrode 11 and the negative electrode 13. Foil 111 and the second lead foil 131 are bent so that the connection between the first lead foil 111 and the first tab 20 and the connection between the second lead foil 131 and the second tab 30 are located on the second side of the core body 10 in its thickness direction. At this time, in the length direction of the core body 10, the tail ends of the first tab 20 and the second tab 30 are far away from the core body 10, so that the first tab 20 and the second tab 30 are led out from one side of the core in its length direction. This reduces the space occupied by the first lead foil 111, the second lead foil 131, the first tab and the second tab in the length direction of the core body 10, and is also beneficial for subsequent shaping.

[0076] Scenario 2, such as Figures 10 to 12 As shown, when the lengths of the first lead foil 111 and the second lead foil 131 are relatively long, the first lead foil 111 and the second lead foil 131 can be bent multiple times. Specifically, when the first lead foil 111 and the second lead foil 131 are not bent, in the length direction of the core body 10, the tail end of the first tab 20 (i.e., the second connecting segment) and the tail end of the second tab 30 (i.e., the fourth connecting segment) are away from the core body 10, and the first lead foil 111 and the second lead foil 131 are located on the first side of the core body 10 in its thickness direction. When bending, the first lead foil 111 and the second lead foil 131 can be bent at one end in the length direction of the core body 10. The lead foil 131 is zig-shaped and bent so that the connection between the first lead foil 111 and the first tab 20 and the connection between the second lead foil 131 and the second tab 30 are located on the first or second side of the core body 10 in its thickness direction. At this time, in the length direction of the core body 10, the tail ends of the first tab 20 and the second tab 30 are far away from the core body 10, so that the first tab 20 and the second tab 30 are led out from one side of the core in its length direction. This reduces the space occupied by the first lead foil 111, the second lead foil 131, the first tab and the second tab in the length direction of the core body 10, and is also beneficial for subsequent shaping.

[0077] In some optional examples of this utility model, the core body 10 has an inner arc side and an outer arc side that are arranged opposite to each other in its thickness direction, and the first lead foil 111 and the second lead foil 131 are located on the outer arc side of the core body 10.

[0078] like Figure 9 As shown, in this example, the core body 10 is a curved flat core, and the first lead foil 111 and the second lead foil 131 are located on the outer arc side of the core body 10, which is beneficial for subsequent shaping and can effectively improve the production efficiency of the battery.

[0079] An embodiment of this utility model also provides a battery, including the winding core unit 100 described in any of the above embodiments. Since the winding core assembly and winding core unit 100 according to the utility model embodiments have the above-described technical effects, the battery according to the utility model embodiments also has corresponding technical effects, which will not be repeated in this embodiment.

[0080] An embodiment of this utility model also provides an electronic device, including the battery described in the above embodiments. Since the winding core assembly and winding core unit 100 according to the utility model embodiments have the above-described technical effects, the electronic device according to the utility model embodiments also has corresponding technical effects, which will not be repeated in this embodiment.

[0081] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A winding core assembly, characterized in that, include: The core body (10) has a positive electrode sheet (11), a separator (12) and a negative electrode sheet (13). The separator (12) separates the positive electrode sheet (11) and the negative electrode sheet (13). The end of the positive electrode sheet (11) is provided with a first lead foil (111) extending along its length direction. The end of the negative electrode sheet (13) is provided with a second lead foil (131) extending along its length direction. The second lead foil (131) is offset from the first lead foil (111). A first tab (20) and a second tab (30), wherein the first tab (20) is used to connect to the first lead foil (111) and the second tab (30) is used to connect to the second lead foil (131).

2. The core assembly according to claim 1, characterized in that, Also includes: An insulating connector (40) is provided with both the first tab (20) and the second tab (30).

3. The core assembly according to claim 1, characterized in that, The diaphragm (12) bonds the positive electrode (11) to the negative electrode (13).

4. The core assembly according to claim 1, characterized in that, The diaphragm (12) is configured as a bag, which is fitted onto the positive electrode (11) or the negative electrode (13).

5. The core assembly according to claim 1, characterized in that, The positive electrode (11) has a first empty foil area (112) on one side, and the first empty foil area (112) corresponds to the position of the starting end of the negative electrode (13).

6. The core assembly according to claim 1, characterized in that, The negative electrode sheet (13) has a negative electrode starting segment, which includes a first sub-segment (132), a bending segment (133), and a second sub-segment (134) connected in sequence. The first sub-segment (132) and the second sub-segment (134) are stacked, and the side of the first sub-segment (132) and the second sub-segment (134) that are close to each other, as well as the inner side of the bent segment (133), are configured as the second empty foil area (135).

7. The core assembly according to claim 1, characterized in that, The outer side of the positive electrode sheet (11) or the negative electrode sheet (13) located on the outer ring of the core body (10) is configured as a third empty foil area, and the third empty foil area is provided with an insulating layer (136).

8. A winding core unit, characterized in that, include: According to any one of claims 1 to 7, the first tab (20) is welded to the first lead-out foil (111), the second tab (30) is welded to the second lead-out foil (131), and the first tab (20) and the second tab (30) are led out from the side of the core body (10); Insulating tape (50) is bonded to the first lead foil (111) and the second lead foil (131), as well as the connection between the first tab (20) and the first lead foil (111) and the connection between the second tab (30) and the second lead foil (131).

9. The core unit according to claim 8, characterized in that, The core body (10) is configured as a curved flat core or a straight flat core.

10. The core unit according to claim 9, characterized in that, The first lead foil (111) and the second lead foil (131) are led out from one side of the length direction of the core body (10). The first lead foil (111) has one or more first bends so that the connection between the first lead foil (111) and the first tab (20) is located on one side of the core body (10) in its thickness direction. The second lead foil (131) has one or more second bends so that the connection between the second lead foil (131) and the second tab (30) is located on one side of the core body (10) in its thickness direction. In the length direction of the core body (10), the tail ends of the first tab (20) and the second tab (30) are away from the core body (10).

11. The core unit according to claim 10, characterized in that, The core body (10) has an inner arc side and an outer arc side arranged opposite to each other in its thickness direction, and the first lead foil (111) and the second lead foil (131) are located on the outer arc side of the core body (10).

12. A battery, characterized in that, Includes the core unit as described in any one of claims 8 to 11.

13. An electronic device, characterized in that, Includes the battery as described in claim 12.

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