Winding battery cell structure and secondary battery

Abstract

The utility model discloses a winding battery cell structure and a secondary battery, and relates to the technical field of secondary batteries, the winding battery cell structure comprises a negative pole piece, a first positive pole piece and a second positive pole piece which are wound on the outer peripheral side of a battery cell winding needle in a reel type structure, and the second positive pole piece is U-shaped; the head parts of the negative pole piece and the first positive pole piece extend into the U-shaped opening of the second positive pole piece, and the head part of the negative pole piece is positioned between the first positive pole piece and the second positive pole piece. The utility model also provides a secondary battery comprising the winding battery core structure. By arranging the second positive pole piece into the U-shaped structure and winding the second positive pole piece on the outer sides of the negative pole piece and the first positive pole piece, the coverage area of the second positive pole piece and the negative pole piece is increased, the active substance of the negative pole piece is fully utilized, and the energy density of the winding type battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of secondary batteries, in particular to a wound battery core structure and a secondary battery. Background Art

[0002] At present, commercial secondary batteries are widely used in the field of power batteries due to their high energy density. The energy density of secondary batteries is closely related to the endurance of new energy vehicles, and the improvement of battery energy density has become the focus of current technology research and development.

[0003] In existing designs, secondary batteries are mostly made by winding the positive electrode sheet, separator, and negative electrode sheet together to form a finished cell. In a wound cell made by continuously coating the electrode sheet, there is no corresponding positive electrode sheet on the inside of the negative electrode and the outside of the end, and the negative electrode active coating is not fully utilized, which reduces the energy density of the cell.

[0004] In the prior art, CN217903143U discloses a wound cell structure and a wound stacked battery, wherein the wound cell structure comprises a first positive electrode sheet, a second positive electrode sheet, a negative electrode sheet and a separator, wherein the first positive electrode sheet is linear and arranged at the heads of the second positive electrode sheet and the negative electrode sheet, such an arrangement makes it possible for only one side of the active material to be opposite to the negative electrode sheet, and the energy density is limited; on the other hand, the head of the negative electrode sheet is a single-sided uncoated negative electrode empty foil area, that is, an AB surface coating method is adopted, which not only increases the coating difficulty, but also the existence of the empty foil area reduces the overall energy density of the battery. Utility Model Content

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide a wound battery cell structure and a secondary battery to solve the problem of low energy density of the battery cell in the prior art.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] On the one hand, the present application provides a wound battery cell structure, including a negative electrode sheet, a first positive electrode sheet and a second positive electrode sheet wound on the outer circumference of a battery cell winding needle in a scroll-like structure, the second positive electrode sheet is U-shaped, the heads of the negative electrode sheet and the first positive electrode sheet are both extended into the U-shaped opening of the second positive electrode sheet, and the head of the negative electrode sheet is located between the first positive electrode sheet and the second positive electrode sheet.

[0008] In some optional embodiments, the second positive electrode plate includes a second positive electrode collector, a positive electrode coating arranged on one side of the second positive electrode collector, and tabs extending from both ends of the second positive electrode collector and integrally formed with the second positive electrode collector.

[0009] In some optional embodiments, the negative electrode plate is coated on both sides, and the head has a negative electrode empty foil area that is uncoated on both sides, the above-mentioned first positive electrode plate is coated on both sides, and the head has a first positive electrode empty foil area that is uncoated on both sides, and the tail has a second positive electrode empty foil area that is uncoated on one side, the negative electrode empty foil area of ​​the above-mentioned negative electrode plate extends into the U-shaped opening of the above-mentioned second positive electrode plate and is opposite to the uncoated surface of the above-mentioned second positive electrode plate, and the first positive electrode empty foil area of ​​the above-mentioned first positive electrode plate partially extends into the U-shaped opening of the above-mentioned second positive electrode plate and is opposite to the uncoated surface of the above-mentioned second positive electrode plate.

[0010] In some optional embodiments, the length of the second positive electrode sheet along the winding direction is the circumference of the battery cell winding needle, the length of the negative electrode empty foil area along the winding direction is / of the circumference of the battery cell winding needle, the length of the first positive electrode empty foil area along the winding direction is / of the circumference of the battery cell winding needle, and the length of the second positive electrode empty foil area along the winding direction is the circumference of the battery cell winding needle.

[0011] In some optional embodiments, the negative electrode plate includes a negative electrode current collector, a first negative electrode coating and a second negative electrode coating respectively arranged on both sides of the negative electrode current collector, and a negative electrode tab arranged at the end of the negative electrode current collector.

[0012] In some optional embodiments, the tails of the first negative electrode coating and the second negative electrode coating are aligned with the tail of the negative electrode current collector, and the lengths of the first negative electrode coating and the second negative electrode coating are less than the length of the negative electrode current collector, thereby forming the negative electrode empty foil area in the area where the head of the negative electrode current collector is not covered.

[0013] In some optional embodiments, the first positive electrode plate includes a first positive electrode collector, a first positive electrode coating and a second positive electrode coating respectively arranged on both sides of the first positive electrode collector, and a positive electrode ear arranged at the end of the first positive electrode collector.

[0014] In some optional embodiments, the first positive electrode coating and the second positive electrode coating are flush on one side of the first positive electrode collector head, and the uncoated area extending along the flush position toward the first positive electrode collector head forms the first positive electrode empty foil area, and the area of ​​the tail of the first positive electrode collector not covered by the second positive electrode coating forms the second positive electrode empty foil area.

[0015] In some optional embodiments, the separator is compounded on both sides of the negative electrode plate.

[0016] On the other hand, the present application also provides a secondary battery, comprising any one of the above-mentioned wound battery cell structures.

[0017] Compared with the prior art, the advantages of the utility model are:

[0018] By setting the second positive electrode sheet as a U-shaped structure and winding it on the outside of the negative electrode sheet and the first positive electrode sheet, the coverage area of ​​the second positive electrode sheet and the negative electrode sheet is increased, the active material of the negative electrode sheet is fully utilized, and the energy density of the wound battery cell is improved; by locating the head of the above-mentioned negative electrode sheet between the above-mentioned first positive electrode sheet and the above-mentioned second positive electrode sheet, when winding, the tail is ended with the positive electrode wrapped around the negative electrode, thereby avoiding the core being in a low potential state due to the end of the negative electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is a structural schematic diagram of a wound battery core structure of the utility model;

[0021] Figure 2 for Figure 1 A schematic top view of the second positive electrode plate;

[0022] Figure 3 for Figure 1 A schematic diagram of a front view of the second positive electrode plate;

[0023] Figure 4 for Figure 1 A schematic top view of the first positive electrode plate;

[0024] Figure 5 for Figure 1 Schematic diagram of the top view of the middle negative electrode.

[0025] In the figure: 1. negative electrode plate; 11. negative electrode empty foil area; 12. negative electrode collector; 13. first negative electrode coating; 14. second negative electrode coating; 15. negative electrode ear; 2. first positive electrode plate; 21. first positive electrode empty foil area; 22. second positive electrode empty foil area; 23. first positive electrode collector; 24. first positive electrode coating; 25. second positive electrode coating; 26. positive electrode ear; 3. second positive electrode plate; 31. ear; 32. second positive electrode collector; 33. positive electrode coating; 4. diaphragm; 41. first diaphragm; 42. second diaphragm. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] The following is a further detailed description of an embodiment of a wound battery cell structure and a secondary battery of the present invention in conjunction with the accompanying drawings.

[0028] like Figure 1 As shown, the present application provides a wound battery cell structure, including a negative electrode sheet 1, a first positive electrode sheet 2 and a second positive electrode sheet 3 wound on the outer circumference of the battery cell winding needle in a scroll-like structure, the second positive electrode sheet 3 is U-shaped, the heads of the negative electrode sheet 1 and the first positive electrode sheet 2 are both extended into the U-shaped opening of the second positive electrode sheet 3, and the head of the negative electrode sheet 1 is located between the first positive electrode sheet 2 and the second positive electrode sheet 3.

[0029] It can be understood that the second positive electrode sheet 3 is located at the center of the wound cell structure and corresponds to the head position of the first positive electrode sheet 2 and the negative electrode sheet 1. By setting the second positive electrode sheet 3 as a U-shaped structure and winding it outside the head position of the negative electrode sheet 1 and the first positive electrode sheet 2, the coverage area of ​​the second positive electrode sheet 3 and the negative electrode sheet 1 is increased, so that the active material of the negative electrode sheet 1 is fully utilized, and the energy density of the wound cell is improved.

[0030] On the other hand, by placing the head of the negative electrode sheet 1 between the first positive electrode sheet 2 and the second positive electrode sheet 3, the tail is wrapped with the positive electrode to end with the negative electrode during winding, thereby preventing the winding core from being in a low potential state due to the end of the negative electrode. This is to solve the problem of short circuit between the shell and the winding core when the shell is charged, such as the outer diaphragm or insulating sheet of the winding core being damaged or leaking in extreme cases; or when the shell is not charged, the outer potential of the winding core is low, and similarly, the outer diaphragm or insulating sheet of the winding core is damaged or leaking in extreme cases, which easily causes the shell corrosion problem.

[0031] In some optional embodiments, such as Figure 2 and Figure 3 As shown, the second positive electrode plate 3 includes a second positive electrode collector 32 , a positive electrode coating 33 arranged on one side of the second positive electrode collector 32 , and tabs 31 extending from both ends of the second positive electrode collector 32 and integrally formed with the second positive electrode collector 32 .

[0032] That is, the positive electrode coating 33 is coated on one side of the second positive electrode current collector 32 , and after coating, the empty foil left by the second positive electrode current collector 32 is punched or laser cut to be the electrode tab 31 .

[0033] Compared with the welding pole ear method, this arrangement does not require the reservation of an empty foil area, and can increase the coating area of ​​the positive electrode coating 33, thereby improving the energy density. The second positive electrode plate 3 uses an integrally formed bipolar ear 31 to ensure that the inner layer of the winding has good conductivity, effectively suppressing the problem of heat generation due to high resistance, and improving the safety of the battery. On the other hand, the side-out pole ear method can also reduce the space layout problem caused by the U-shaped winding of the positive pole plate and reduce the occupied thickness.

[0034] In some optional embodiments, such as Figure 5 As shown, the negative electrode plate 1 is coated on both sides, and the head has a negative electrode empty foil area 11 that is not coated on both sides, the first positive electrode plate 2 is coated on both sides, and the head has a first positive electrode empty foil area 21 that is not coated on both sides, and the tail has a second positive electrode empty foil area 22 that is not coated on one side, the negative electrode empty foil area 11 of the negative electrode plate 1 extends into the U-shaped opening of the second positive electrode plate 3 and is opposite to the uncoated surface of the second positive electrode plate 3, and the first positive electrode empty foil area 21 of the first positive electrode plate 2 partially extends into the U-shaped opening of the second positive electrode plate 3 and is opposite to the uncoated surface of the second positive electrode plate 3.

[0035] It can be understood that both the negative electrode sheet 1 and the first positive electrode sheet 2 are continuously coated. When the negative electrode sheet 1 is coated, a negative electrode empty foil area 11 with double-sided uncoated is left at one end. When the first positive electrode sheet 2 is coated, a first positive electrode empty foil area 21 with double-sided uncoated is left at one end, and a second positive electrode empty foil area 22 with single-sided uncoated is left on one side of the other end. The negative electrode empty foil area 11 with double-sided uncoated and the first positive electrode empty foil area 21 with single-sided uncoated are both used for welding the pole ears, and the second positive electrode empty foil area 22 with single-sided uncoated is used for the final finishing. Since it is located at the outermost side, it does not need to be coated on both sides, avoiding waste of the coating area and saving costs.

[0036] In this example, the negative electrode plate 1 is coated on both sides, and the double-sided coating areas fully correspond to the coating areas of the first positive electrode plate 2 and the second positive electrode plate 3, so that the negative electrode active coating is fully utilized, thereby improving the energy density of the wound battery cell.

[0037] In some optional embodiments, the length of the second positive electrode sheet 3 along the winding direction is the circumference of the battery cell winding needle, the length of the negative electrode empty foil area 11 along the winding direction is 1 / 2 of the circumference of the battery cell winding needle, the length of the first positive electrode empty foil area 21 along the winding direction is 1 / 4 of the circumference of the battery cell winding needle, and the length of the second positive electrode empty foil area 22 along the winding direction is the circumference of the battery cell winding needle.

[0038] like Figure 1 As shown in the figure, since the negative electrode sheet 1, the first positive electrode sheet 2 and the second positive electrode sheet 3 are all wound on the outside of the battery cell winding needle, the length of the second positive electrode sheet 3 is set to the circumference of the battery cell winding needle, the length of the negative electrode empty foil area 11 is set to 1 / 2 of the circumference of the battery cell winding needle, the length of the first positive electrode empty foil area 21 is set to 1 / 4 of the circumference of the battery cell winding needle, and the length of the second positive electrode empty foil area 22 is set to the circumference of the battery cell winding needle, all of which are to improve the effective utilization rate of the active materials and reduce costs while ensuring the energy density of the battery cell.

[0039] It should be noted that Figure 1 The figure is a schematic diagram of the wound battery cell structure. In order to fully demonstrate the relative position and winding method of each electrode piece, the winding density and the winding circumference of each electrode piece are magnified during winding.

[0040] In some optional embodiments, such as Figure 5 As shown, the negative electrode sheet 1 includes a negative electrode current collector 12 , a first negative electrode coating 13 and a second negative electrode coating 14 respectively arranged on both sides of the negative electrode current collector 12 , and a negative electrode tab 15 arranged at the end of the negative electrode current collector 12 .

[0041] It can be understood that the coating areas of the first negative electrode coating 13 and the second negative electrode coating 14 can be equal or different. In this example, since the second positive electrode plate 3 is arranged in a U-shaped winding manner, the positions of the first negative electrode coating 13 and the second negative electrode coating 14 can be made corresponding to the coating area positions of the second positive electrode plate 3 and the first positive electrode plate 2.

[0042] In this example, the tails of the first negative electrode coating 13 and the second negative electrode coating 14 are aligned with the tails of the negative electrode current collector 12, and the lengths of the first negative electrode coating 13 and the second negative electrode coating 14 are smaller than the length of the negative electrode current collector 12, thereby forming the negative electrode empty foil area 11 in the area where the head of the negative electrode current collector 12 is not covered.

[0043] It is understandable that Figure 5 As shown, the coating areas of the first negative electrode coating 13 and the second negative electrode coating 14 are equal, and the first negative electrode coating 13 and the second negative electrode coating 14 are located on one side of the tail of the negative electrode collector 12 and are flush with the negative electrode collector 12 to maximize the area of ​​the coating active material and correspond to the coating area of ​​the second positive electrode plate 3.

[0044] In some optional embodiments, such as Figure 4 As shown, the first positive electrode plate 2 includes a first positive electrode collector 23 , a first positive electrode coating 24 and a second positive electrode coating 25 respectively arranged on both sides of the first positive electrode collector 23 , and a positive electrode tab 26 arranged at the end of the first positive electrode collector 23 .

[0045] Furthermore, the first positive electrode coating 24 and the second positive electrode coating 25 are flush with each other on one side of the head of the first positive electrode collector 23, and the uncoated area extending from the flush position to the head of the first positive electrode collector 23 forms the first positive electrode empty foil area 21, and the area at the tail of the first positive electrode collector 23 not covered by the second positive electrode coating 25 forms the second positive electrode empty foil area 22.

[0046] That is to say, the coating areas of the first positive electrode coating 24 and the second positive electrode coating 25 are not equal and partially overlap, so that the coatings on both sides of the first positive electrode plate 2 are coated in the manner of A and B. The first positive electrode empty foil area 21 is used for welding the positive electrode tab 26, and the second positive electrode empty foil area 22 covers the tail of the negative electrode plate 1 and is located at the outermost side of the wound battery cell structure, so there is no need to coat the active material.

[0047] In some optional embodiments, the separator 4 is composited on the second positive electrode current collector 32 and the positive electrode coating 33 .

[0048] It can be understood that the separator 4 is used to separate the positive electrode sheet and the negative electrode sheet to prevent the positive and negative electrodes from contacting each other and causing a short circuit in the battery. In this example, the negative electrode sheet 1 and the separators 4 on both sides are connected by hot melting or hot pressing to form a composite layer.

[0049] Specifically, Figure 1 As shown, the separator 4 includes a first separator 41 and a second separator 42. The head of the first separator 41 is wound from the end of the second positive electrode sheet 3 located outside the first positive electrode sheet 2, along the outside of the positive electrode coating 33, so as to completely cover the positive electrode coating 33 and the second positive electrode collector 32 of the second positive electrode sheet 3, and is wound along the outside of the first positive electrode sheet 2 to the tail of the first positive electrode sheet 2; the head of the second separator 42 is wound from the outside of the head of the negative electrode sheet 1 to the tail of the negative electrode sheet 1.

[0050] This arrangement can ensure that a separator is provided between two adjacent positive and negative electrode sheets, and at the same time cooperate with the U-shaped wound second positive electrode sheet to achieve the most optimized separator winding method.

[0051] On the other hand, the present application also provides a secondary battery, comprising any one of the above-mentioned wound battery cell structures.

[0052] Specifically, the secondary battery includes an outer packaging aluminum-plastic film, a wound cell structure arranged inside the outer packaging aluminum-plastic film, and an electrolyte filled between the outer packaging aluminum-plastic film and the wound cell structure. The wound cell structure includes a negative electrode sheet 1, a first positive electrode sheet 2, and a second positive electrode sheet 3 wound on the outer circumference of the cell winding needle in a scroll-like structure, the second positive electrode sheet 3 is U-shaped, the heads of the negative electrode sheet 1 and the first positive electrode sheet 2 are both inserted into the U-shaped opening of the second positive electrode sheet 3, and the head of the negative electrode sheet 1 is located between the first positive electrode sheet 2 and the second positive electrode sheet 3.

[0053] The utility model discloses a wound cell structure and a secondary battery, wherein the second positive electrode sheet 3 is set as a U-shaped structure and is wound around the outside of the negative electrode sheet 1 and the first positive electrode sheet 2, thereby increasing the coverage area of ​​the second positive electrode sheet 3 and the negative electrode sheet 1, making full use of the active material of the negative electrode sheet 1, and improving the energy density of the wound cell; the head of the negative electrode sheet 1 is located between the first positive electrode sheet 2 and the second positive electrode sheet 3, so that when winding, the tail is wrapped with the positive electrode to end with the negative electrode, thereby avoiding the winding core being in a low potential state due to the end of the negative electrode; by side-out tabs 31 at both ends of the second positive current collector 32, not only can the coating area of ​​the positive electrode coating 33 be increased, thereby improving the energy density, but also the second positive electrode sheet 3 adopts an integrally formed bipolar tab 31 to ensure that the inner layer of the winding has good conductivity. Electrical properties, effectively suppressing the problem of heat generation due to large resistance, improving the safety of the battery, and the side-out tab method can also reduce the space layout problem caused by the U-shaped winding of the positive electrode plate, reducing the occupied thickness; the negative electrode plate 1 is double-sided coated, and the double-sided coating areas fully correspond to the coating areas of the first positive electrode plate 2 and the second positive electrode plate 3, so that the negative electrode active coating is fully utilized, thereby improving the energy density of the wound battery cell; the length of the second positive electrode plate 3 is set to the circumference of the battery cell winding needle, the length of the negative electrode empty foil area 11 is set to 1 / 2 of the circumference of the battery cell winding needle, the length of the first positive electrode empty foil area 21 is set to 1 / 4 of the circumference of the battery cell winding needle, and the length of the second positive electrode empty foil area 22 is set to the circumference of the battery cell winding needle, all of which are to improve the effective utilization rate of the active material, while ensuring the energy density of the battery cell, reducing the cost.

[0054] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0055] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0056] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A wound battery cell structure, characterized in that: The invention comprises a negative electrode sheet (1), a first positive electrode sheet (2) and a second positive electrode sheet (3) which are wound around the outer periphery of a battery cell winding needle in a reel-like structure, wherein the second positive electrode sheet (3) is U-shaped, and the heads of the negative electrode sheet (1) and the first positive electrode sheet (2) are both inserted into the U-shaped opening of the second positive electrode sheet (3), and the head of the negative electrode sheet (1) is located between the first positive electrode sheet (2) and the second positive electrode sheet (3).

2. The wound battery core structure according to claim 1, characterized in that: The second positive electrode plate (3) comprises a second positive electrode current collector (32), a positive electrode coating (33) arranged on one side of the second positive electrode current collector (32), and pole ears (31) extending from both ends of the second positive electrode current collector (32) and integrally formed with the second positive electrode current collector (32).

3. The wound battery cell structure according to claim 2, characterized in that: The negative electrode sheet (1) is coated on both sides, and the head portion has a negative electrode empty foil area (11) that is not coated on both sides; the first positive electrode sheet (2) is coated on both sides, and the head portion has a first positive electrode empty foil area (21) that is not coated on both sides; the tail portion has a second positive electrode empty foil area (22) that is not coated on one side; the negative electrode empty foil area (11) of the negative electrode sheet (1) extends into the U-shaped opening of the second positive electrode sheet (3) and is opposite to the uncoated surface of the second positive electrode sheet (3); the first positive electrode empty foil area (21) of the first positive electrode sheet (2) partially extends into the U-shaped opening of the second positive electrode sheet (3) and is opposite to the uncoated surface of the second positive electrode sheet (3).

4. The wound battery core structure according to claim 3, characterized in that: The length of the second positive electrode sheet (3) along the winding direction is the circumference of the battery cell winding needle, the length of the negative electrode empty foil area (11) along the winding direction is 1 / 2 of the circumference of the battery cell winding needle, the length of the first positive electrode empty foil area (21) along the winding direction is 1 / 4 of the circumference of the battery cell winding needle, and the length of the second positive electrode empty foil area (22) along the winding direction is the circumference of the battery cell winding needle.

5. The wound battery core structure according to claim 3, characterized in that: The negative electrode sheet (1) comprises a negative electrode current collector (12), a first negative electrode coating (13) and a second negative electrode coating (14) respectively arranged on two surfaces of the negative electrode current collector (12), and a negative electrode tab (15) arranged at the end of the negative electrode current collector (12).

6. The wound battery cell structure according to claim 5, characterized in that: The tails of the first negative electrode coating (13) and the second negative electrode coating (14) are aligned with the tail of the negative electrode current collector (12), and the lengths of the first negative electrode coating (13) and the second negative electrode coating (14) are shorter than the length of the negative electrode current collector (12), thereby forming the negative electrode empty foil area (11) in the area where the head of the negative electrode current collector (12) is not covered.

7. The wound battery cell structure according to claim 3, characterized in that: The first positive electrode plate (2) comprises a first positive electrode current collector (23), a first positive electrode coating (24) and a second positive electrode coating (25) respectively arranged on two sides of the first positive electrode current collector (23), and a positive electrode tab (26) arranged at the end of the first positive electrode current collector (23).

8. The wound battery cell structure according to claim 7, characterized in that: The first positive electrode coating (24) and the second positive electrode coating (25) are located flush with each other on one side of the head of the first positive electrode collector (23), and the uncoated area extending from the flush position toward the head of the first positive electrode collector (23) forms the first positive electrode empty foil area (21), and the area of ​​the tail of the first positive electrode collector (23) not covered by the second positive electrode coating (25) forms the second positive electrode empty foil area (22).

9. The wound battery core structure according to claim 2, characterized in that: The separator (4) is composited on both sides of the negative electrode plate (1).

10. A secondary battery, characterized in that: The invention comprises the wound battery core structure according to any one of claims 1 to 9.

Images