CN220604925U - Battery cell - Google Patents

Abstract

The utility model relates to a battery, which comprises a shell, a first winding core and a second winding core, wherein the first winding core and the second winding core are arranged in the shell, the first winding core comprises a first tab, a first negative plate, a first diaphragm and a first positive plate which are sequentially overlapped, one of the first negative plate and the first positive plate is provided with a first empty foil area, and the other one is connected with the first tab; the second winding core comprises a second lug, a second negative plate, a second diaphragm and a second positive plate which are sequentially overlapped, one of the second negative plate and the second positive plate is provided with a second empty foil area, and the other is connected with the second lug; the polarity of the electrodes of the first empty foil area is opposite to that of the electrodes of the second empty foil area, and the first empty foil area is welded with the second empty foil area. The battery is directly welded through the first empty foil area of the first winding core and the second empty foil area of the second winding core, and the two are not required to be welded with the electrode lugs, so that the stacking thickness of the double winding cores is reduced, and the arrangement mode of the two winding cores is more flexible.

Description

Battery cell

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery.

Background

The battery is widely applied to equipment such as electric vehicles, communication base stations, emergency equipment and the like as energy storage equipment. Currently, in order to increase the power supply voltage of a battery, as shown in fig. 1, two battery cells are often required to be connected in series, wherein the battery includes two battery cells, namely, a first battery cell 1 'and a second battery cell 2', namely, a first positive tab 11 'of the first battery cell 1' is connected with a second negative tab 21 'of the second battery cell 2', and a first negative tab 12 'of the first battery cell 1' and a second positive tab 22 'of the second battery cell 2' are used for connecting an external electrical appliance. The prior art has the following defects: the two battery cores are all required to be connected in series by welding the first positive lug 11 'and the second negative lug 21' on the pole piece, and the internal resistance of the battery can be increased by connecting the two winding cores through the two lugs. Meanwhile, welding the first positive tab 11 'and the second negative tab 21' for connection to the two battery cells increases the thickness of the winding core, thereby reducing the energy density of the battery.

Disclosure of Invention

The aim of the embodiment of the utility model is that: the battery is simple in structure, high in energy density and small in internal resistance.

To achieve the purpose, the embodiment of the utility model adopts the following technical scheme:

provided is a battery including:

a housing;

the first winding core is arranged in the shell and comprises a first negative plate, a first diaphragm and a first positive plate which are sequentially arranged, one of the first negative plate and the first positive plate is provided with a first empty foil area, and the other one of the first negative plate and the first positive plate is connected with the first tab;

the second winding core is arranged in the shell and comprises a second negative plate, a second diaphragm and a second positive plate which are sequentially arranged, one of the second negative plate and the second positive plate is provided with a second empty foil area, and the other is connected with the second lug;

the polarity of the electrodes of the first empty foil area is opposite to that of the electrodes of the second empty foil area, and the first empty foil area is connected with the second empty foil area.

As a preferred solution of the battery, the first empty foil area is disposed at one end of the first negative electrode sheet or the first positive electrode sheet far away from the winding center of the first winding core; and/or the number of the groups of groups,

the second empty foil area is arranged at one end of the second negative electrode plate or the second positive electrode plate, which is far away from the winding center of the second winding core.

As a preferred embodiment of the battery, the first empty foil area and the second empty foil area are arranged at least partially overlapping.

As a preferred embodiment of the battery, an insulating layer is provided at least in the outer sidewall region where the first winding core and the second winding core are in contact or adjacent.

As a preferred embodiment of the battery, the insulating layer is a gummed paper or a ceramic layer.

As a preferred embodiment of the battery, the winding direction of the first winding core is the same as the winding direction of the second winding core.

As a preferred embodiment of the battery, the cross sections of the first winding core and the second winding core are elliptical;

the length of the first empty foil area is L1, the long axis of the first winding core is A1, the short axis of the first winding core is B1, A1-B1 is less than or equal to L1 and less than or equal to 2 (A1-B1); and/or the number of the groups of groups,

the length of the second empty foil area is L2, the long axis of the second winding core is A2, the short axis of the second winding core is B2, A2-B2 is less than or equal to L2 and less than or equal to 2 (A2-B2).

As a preferred embodiment of the battery, the winding direction of the first winding core is opposite to the winding direction of the second winding core.

As a preferred embodiment of the battery, the cross sections of the first winding core and the second winding core are elliptical;

the length of the first empty foil area is L1, the long axis of the first winding core is A1, the short axis of the first winding core is B1, A1+B1 is less than or equal to L1 and less than or equal to 2 (A1+B1); and/or the number of the groups of groups,

the length of the second empty foil area is L2, the long axis of the first winding core is A2, the short axis of the first winding core is B2, A2+B2 is less than or equal to L2 and less than or equal to 2 (A2+B2).

As a preferred embodiment of the battery, the winding start position of the first winding core is on the first negative electrode sheet or the first positive electrode sheet; and/or the number of the groups of groups,

the winding initial position of the second winding core is on the second negative plate or the second positive plate.

As a preferable mode of the battery, one of the first positive electrode sheet and the first negative electrode sheet, which is not provided with the first empty foil region, is provided with at least one first foil guiding portion protruding in the width direction thereof;

as a preferred embodiment of the battery, all the first foil guiding portions are connected with the first tab

As a preferable mode of the battery, one of the second positive electrode sheet and the second negative electrode sheet, which is not provided with the second empty foil region, is provided with at least one second foil guiding portion protruding in the width direction thereof.

As a preferred embodiment of the battery, all of the second foil guiding portions are connected to the second tab.

As a preferred scheme of the battery, one of the first positive electrode sheet and the first negative electrode sheet, which is not provided with the first empty foil region, is provided with a third empty foil region, the third empty foil region is connected with a first tab, and the third empty foil region is positioned at one end of the first positive electrode sheet or the first negative electrode sheet, which is adjacent to the winding center of the first winding core; and/or the number of the groups of groups,

one of the second positive electrode plate and the second negative electrode plate, which is not provided with the second empty foil area, is provided with a fourth empty foil area, the fourth empty foil area is connected with a second lug, and the fourth empty foil area is positioned at one end of the second positive electrode plate or the second negative electrode plate, which is adjacent to the winding center of the second winding core.

The embodiment of the utility model has the beneficial effects that: the battery is with first reel core and second reel core all set up in the casing, can make the structure of battery compacter, and can reduce the occupation space of casing, increased the energy density of battery. The first hollow foil area is arranged on the first positive plate or the first negative plate of the first winding core, the second hollow foil area is arranged on the second positive plate or the second negative plate of the second winding core, and the first hollow foil area and the second hollow foil area are welded. In the design, the first empty foil area is directly connected with the second empty foil area, the first empty foil area and the second empty foil area are not required to be welded with the electrode lug, and the contact internal resistance between the electrode plates can be reduced due to the large welding area of the first empty foil area and the second empty foil area, so that the contact internal resistance of the whole battery is reduced. In addition, the first empty foil area and the second empty foil area are not connected through the pole lugs, so that the thickness of the first winding core and the thickness of the second winding core are reduced, and the energy density of the battery is further increased.

Drawings

The utility model is described in further detail below with reference to the drawings and examples.

Fig. 1 is a schematic view of a prior art battery

Fig. 2 is a cross-sectional view of a battery according to an embodiment of the present utility model.

Fig. 3 is a cross-sectional view of a battery according to another embodiment of the present utility model.

Fig. 4 is a schematic diagram showing the connection of the first empty foil area and the second empty foil area according to an embodiment of the present utility model.

Fig. 5 is a partially developed schematic illustration of a first negative electrode sheet according to an embodiment of the utility model.

FIG. 6 is a partially developed view of a second positive electrode sheet according to an embodiment of the utility model

In fig. 1:

1', a first winding core; 11', a first positive tab; 12', a first negative electrode ear; 2', a second winding core; 21', a second positive tab; 22', a second negative electrode ear;

fig. 2-6:

1. a housing; 2. a first winding core; 21. a first tab; 22. a first negative electrode sheet; 221. a third empty foil region; 222. a first foil guiding portion; 23. a first diaphragm; 24. a first positive electrode sheet; 241. a first empty foil region; 3. a second winding core; 31. a second lug; 32. a second negative electrode sheet; 321. a second empty foil region; 33. a second diaphragm; 34. a second positive electrode sheet; 341. a fourth empty foil region; 342. a second foil guiding portion; 4. an insulating layer.

Detailed Description

In order to make the technical problems solved by the present utility model, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present utility model will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to fall within the scope of the utility model.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

As shown in fig. 2 and 3, the present utility model provides a battery including a case 1, a first winding core 2 and a second winding core 3, the first winding core 2 being disposed in the case 1, the first winding core 2 including a first negative electrode sheet 22, a first separator 23 and a first positive electrode sheet 24 disposed in this order, one of the first negative electrode sheet 22 and the first positive electrode sheet 24 being provided with a first empty foil region 241, the other being connected to a first tab 21; the second winding core 3 is arranged in the shell 1, the second winding core 3 comprises a second negative plate 32, a second diaphragm 33 and a second positive plate 34 which are sequentially arranged, one of the second negative plate 32 and the second positive plate 34 is provided with a second empty foil area 321, and the other is connected with the second lug 31; the polarity of the electrodes of the first and second empty foil areas 241, 321 is opposite, and the first empty foil area 241 is connected to the second empty foil area 321.

The battery of this embodiment is with first reel core 2 and the equal setting of second reel core 3 in casing 1, can make the structure of battery compacter, and can reduce the occupation space of casing 1, has increased the energy density of battery. By arranging the first empty foil region 241 on the first positive plate 24 or the first negative plate 22 of the first winding core 2, arranging the second empty foil region 321 on the second positive plate 34 or the second negative plate 32 of the second winding core 3, and welding the first empty foil region 241 and the second empty foil region 321, the first winding core 2 and the second winding core 3 can be connected in series due to the opposite polarities of the electrodes of the second empty foil region 321 and the first empty foil region 241, so that the discharge voltage of the battery is increased, and the battery is suitable for more application scenes. In this design, the first empty foil area 241 and the second empty foil area 321 are directly connected, and the two areas do not need to be welded to connect with the tab, and the larger welding area of the two areas can reduce the contact internal resistance between the pole pieces, thereby reducing the contact internal resistance of the whole battery. In addition, the first and second empty foil sections 241 and 321 do not need to be connected by tabs, and the thickness of the first and second winding cores 2 and 3 is reduced, thereby further increasing the energy density of the battery. It will be appreciated that the pole piece is wound lengthwise with the diaphragm.

One of the first negative electrode sheet 22 and the first positive electrode sheet 24, which is not provided with a first empty foil area, is connected with the first tab 21, one of the second negative electrode sheet 32 and the second positive electrode sheet 34, which is not provided with a second empty foil area, is connected with the second tab, one of the first tab 21 and the second tab 31 is a positive tab, the other is a negative tab, and the positive tab and the negative tab are used for being connected with a pole and connected to an external electric appliance so as to supply power for the electric appliance.

In this embodiment, the first empty foil area 241 and the second empty foil area 321 are welded, so that the first empty foil area 241 and the second empty foil area 321 are connected more tightly, so as to reduce the internal resistance of the winding core.

Alternatively, the first negative electrode sheet 22, the first separator 23, and the first positive electrode sheet 24 are sequentially stacked and wound to form a first winding core; the second negative electrode sheet 32, the second separator 33, and the second positive electrode sheet 34 are stacked in this order and wound to form a second winding core.

Alternatively, the housing 1 may be made of steel, aluminum, copper or other materials. Wherein the case 1 may serve as an outermost layer of the bare cell. The shape of the housing 1 may be a cylinder, a tri-diamond, a tetra-diamond, or other shapes, and is not limited to the present embodiment.

In the present embodiment, the first empty foil region 241 is disposed on the first positive electrode sheet 24, and the second empty foil region 321 is disposed on the second negative electrode sheet 32. The polarity of the first empty foil area 241 is thus positive and the polarity of the second empty foil area 321 is negative. Wherein the first empty foil area 241 is copper foil and the second empty foil area 321 is aluminum foil. In other embodiments, the blank foil region may be made of other materials, not limited to the present embodiment.

In other embodiments, the first empty foil region 241 is disposed on the first negative electrode sheet 22, and the second empty foil region 321 is disposed on the second positive electrode sheet 34, in which embodiment the polarity of the first empty foil region 241 is negative and the polarity of the second empty foil region 321 is positive.

It should be noted that the pole piece includes a current collector and an active layer disposed on two opposite sides of the current collector, the active layer is capable of chemically reacting with the electrolyte to form a current, and the current collector is used for guiding the formed current. Wherein the area of the current collector not coated with the active layer is an empty foil area.

Specifically, the first empty foil region 241 is disposed at one end of the first negative electrode sheet 22 or the first positive electrode sheet 24 away from the winding center of the first winding core 2; the second empty foil area 321 is disposed at an end of the second negative electrode sheet 32 or the second positive electrode sheet 34 away from the winding center. In this embodiment, the first positive electrode sheet 24 is far away from the winding center of the first winding core 2, and the second empty foil area 321 is arranged at the end of the second negative electrode sheet 32 far away from the winding center of the second winding core 3, so that on one hand, the production and the manufacturing of the first positive electrode sheet 24 and the second negative electrode sheet 32 are facilitated, and an active layer is not required to be coated at the end parts of the first positive electrode sheet and the second negative electrode sheet 32, and an empty foil area is directly formed; on the other hand, the first empty foil region 241 and the second empty foil region 321 are both at the outer periphery, facilitating welding of the first empty foil region 241 and the second empty foil region 321.

In other embodiments, the first empty foil region 241 may also be disposed at a non-end region of the first negative electrode sheet 22 or the first positive electrode sheet 24, and the second empty foil region 321 may also be disposed at a non-end region of the second negative electrode sheet 32 or the second positive electrode sheet 34.

In an alternative embodiment, the first empty foil area 241 and the second empty foil area 321 are only partially overlapped, so that the contact area of the first empty foil area 241 and the second empty foil area 321 is increased, and the internal resistance of the two winding cores is reduced. Preferably, the first empty foil area 241 and the second empty foil area 321 are equal, and the first empty foil area 241 covers the entire side of the second empty foil area 321.

In some embodiments, as shown in fig. 4, the end surfaces of the first and second hollow foil regions 241, 321 may be welded.

In another embodiment, as shown in fig. 2, the winding direction of the first winding core 2 is the same as the winding direction of the second winding core 3, so that the first winding core 2 and the second winding core 3 can be vertically stacked in the case 1. In this design, after the first winding core 2 and the second winding core 3 are wound, the first empty foil area 241 and the second empty foil area 321 may be attached to each other along the winding direction, so as to reduce the gap between the two winding cores, thereby increasing the energy density of the battery.

In other embodiments, as shown in fig. 3, the first winding core 2 and the second winding core 3 may be stacked horizontally in the case 1 when the winding direction of the first winding core 2 is opposite to the winding direction of the second winding core 3.

Specifically, an insulating layer 4 is provided at least in the outer sidewall area where the first winding core 2 and the second winding core 3 are in contact, to prevent the first winding core 2 and the second winding core 3 from being accidentally in contact to cause a short circuit in the case 1.

In this embodiment, the cross sections of the first winding core 2 and the second winding core 3 are elliptical. In other embodiments, the first winding core 2 or the second winding core 3 may be circular, so the insulating layer 4 is disposed at the rounded corners of the first winding core 2 and the second winding core 3, and in other embodiments, the cross section of the first winding core 2 or the second winding core 3 may be other shapes.

Specifically, when the winding direction of the first winding core 2 is the same as the winding direction of the second winding core 3, the first winding core 2 and the second winding core 3 are provided with insulating layers 4 on opposite side walls; when the winding direction of the first winding core 2 is opposite to the winding direction of the second winding core 3, the insulating layer 4 is provided on the side wall of the first winding core 3 facing the second winding core.

Optionally, the insulating layer 4 is a ceramic layer. The ceramic layer is thinner than the insulating separator, which can reduce the volume of the winding core, thereby increasing the energy density of the battery. In this embodiment, the insulating layer 4 may be formed by spraying or coating on the side wall of the winding core.

Optionally, the ceramic layer is made of a mixture of an electrically insulating material and a binder.

Alternatively, the electrically insulating material may be alumina, boehmite, mayenite, zirconia or other insulating material.

Alternatively, the binder may be PVDF, SBR, aqueous polyurethane, or the like.

In another embodiment, the insulating layer 4 is gummed paper.

It can be understood that when the outermost layer of the winding core is the negative plate, the insulating layer is arranged on the negative plate; when the outermost layer of the winding core is arranged on the positive plate, the insulating layer is arranged on the positive plate.

In some embodiments, the winding start position of the first winding core 2 is on the first negative electrode sheet 22 or the first positive electrode sheet 24; and/or the winding start position of the second winding core 3 is on the second negative electrode sheet 32 or the second positive electrode sheet 34. It can be understood that, when winding, the winding core has an initial winding area, wherein the positive electrode sheet and the negative electrode sheet are stacked on two sides of the separator, when the winding core starts winding from one side of the positive electrode sheet, the winding initial position is the positive electrode sheet, and the winding initial area is located on one side surface of the positive electrode sheet away from the separator; when the winding core starts winding from one side of the negative electrode sheet, the winding start position is the negative electrode sheet, and the winding start region is located on one side of the negative electrode sheet separator.

In another embodiment, as shown in fig. 2, the winding direction of the first winding core 2 is the same as the winding direction of the second winding core 3, and meanwhile, the sections of the first winding core 2 and the second winding core 3 are elliptical; the length of the first empty foil region 241 is L1, the major axis of the first winding core 2 is A1 (the major axis refers to the major axis constant of the first winding core 2 in an elliptical shape), the minor axis of the first winding core 2 is B1 (the minor axis refers to the minor axis constant of the first winding core 2 in an elliptical shape), and A1-B1 is equal to or less than L1 and equal to or less than 2 (A1-B1); and/or the length of the second empty foil area 321 is L2, the long axis of the second winding core 3 is A2, the short axis of the second winding core 3 is B2, and A2-B2 is less than or equal to L2 and less than or equal to 2 (A2-B2). Through this design, can guarantee to fold perpendicularly and establish the first empty foil district 241 of two cores and have sufficient area of contact between the empty foil district 321 of second, avoid empty foil district's area too short and influence the stability that both contacted, avoid empty foil district's length too big and influence the coating area of active layer.

In yet another embodiment, the winding direction of the first winding core 2 is opposite to the winding direction of the second winding core 3, the cross sections of the first winding core 2 and the second winding core 3 are elliptical, the length of the first empty foil region 241 is L1, the long axis of the first winding core 2 is A1, the short axis of the first winding core 2 is B1, a1+b1 is less than or equal to l1 is less than or equal to 2 (a1+b1); and/or the length of the second empty foil area 321 is L2, the long axis of the second winding core 3 is A2, the short axis of the second winding core 3 is B2, a2+b2 is equal to or less than L2 is equal to or less than 2 (a2+b2). Likewise, by the design, the first empty foil area 241 and the second empty foil area 321 of the two horizontally stacked winding cores can be ensured to have enough contact area, the contact stability of the two areas is prevented from being influenced due to the too short area of the empty foil area, the coating area of the active layer is prevented from being influenced due to the too long length of the empty foil area, and the energy density of the battery is ensured.

In an alternative embodiment, as shown in fig. 5, one of the first positive electrode sheet 24 and the first negative electrode sheet 22, which is not provided with the first empty foil region 241, is convexly provided with at least two first foil guiding portions 222 along the width direction thereof, in this embodiment, the first foil guiding portions 222 are disposed on the first negative electrode sheet 22, and all the first foil guiding portions 222 can be used as tabs together. And/or, as shown in fig. 6, one of the second positive electrode tab 34 and the second negative electrode tab 32 connected to the second tab 31 is provided with at least one second foil guiding portion protruding in the width direction thereof. In this embodiment, the second foil guiding portions 342 are disposed on the second positive electrode sheet 34, and all the second foil guiding portions 342 can be used as tabs together. It will be appreciated that by this design, the internal resistance of the winding core can be further reduced by drawing a portion of the blank foil in a die cut fashion over the pole piece to form the first and second lead foil portions 222, 342.

In another alternative embodiment, all of the first foil guiding portions 222 are connected to the first tab 21; and/or all of the second foil portions 342 are connected to the second tab 31. The foil guiding part is connected with the tab, so that a multi-tab structure can be formed, and the effect of reducing the internal resistance of the winding core is achieved.

In other embodiments, when the first empty foil region 241 is disposed on the first negative electrode sheet 22 and the second empty foil region 321 is disposed on the second positive electrode sheet 34, the first foil guiding portion 222 is disposed on the first positive electrode sheet 24 and the second foil guiding portion 342 is disposed on the second negative electrode sheet 32.

In another alternative embodiment, one of the first positive electrode sheet 24 and the first negative electrode sheet 22, which is not provided with the first empty foil region 241, is provided with a third empty foil region 221, the third empty foil region 221 is connected with the first tab 21, in this embodiment, the third empty foil region 221 is provided on the first negative electrode sheet 22, the first tab 21 is connected with the third empty foil region 221, and the third empty foil region 221 is located at one end of the first positive electrode sheet 24 or the first negative electrode sheet 22 adjacent to the winding center of the first winding core 2; and/or, the second hollow foil region 321 is not provided in one of the second positive electrode sheet 34 and the second negative electrode sheet 32, and the fourth hollow foil region 341 is connected to the second tab 31, in this embodiment, the fourth hollow foil region 341 is provided on the second negative electrode sheet 32, the second tab is connected to the fourth hollow foil region 341, and the fourth hollow foil region 341 is located at one end of the first negative electrode sheet 22 adjacent to the winding center of the second winding core 3. The arrangement of the end part of the pole piece in the empty foil area is beneficial to the processing and manufacturing of the pole piece, thereby reducing the manufacturing cost of the battery. In other embodiments, when the first empty foil region 241 is disposed on the first negative electrode sheet 22, the second empty foil region 321 is disposed on the second positive electrode sheet 34, the third empty foil region 221 is disposed on the first positive electrode sheet 24, and the fourth empty foil region 341 is disposed on the second negative electrode sheet 32.

In some embodiments, the third blank foil region 221 is disposed in a non-end region of the first negative electrode sheet 22, and the fourth blank foil region 341 is disposed in a non-end region of the second positive electrode sheet 34.

In the description herein, it should be understood that the terms "upper," "lower," and the like are used for convenience in description and simplicity of operation only, and are not necessarily indicative or implying any particular orientation, configuration or operation of such apparatus or elements herein, and therefore should not be construed as limiting the present utility model.

In the description of the present specification, reference to the term "an embodiment" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment.

Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in the foregoing embodiments, and that the embodiments described in the foregoing embodiments may be combined appropriately to form other embodiments that will be understood by those skilled in the art.

The technical principle of the present utility model is described above in connection with the specific embodiments. The description is made for the purpose of illustrating the general principles of the utility model and should not be taken in any way as limiting the scope of the utility model. Other embodiments of the utility model will be apparent to those skilled in the art from consideration of this specification without undue burden.

Claims (15)

1. A battery, comprising:

a housing;

the first winding core is arranged in the shell and comprises a first negative plate, a first diaphragm and a first positive plate which are sequentially arranged, and one of the first negative plate and the first positive plate is provided with a first empty foil area;

the second winding core is arranged in the shell and comprises a second negative plate, a second diaphragm and a second positive plate which are sequentially arranged, and one of the second negative plate and the second positive plate is provided with a second empty foil area;

the polarity of the electrodes of the first empty foil area is opposite to that of the electrodes of the second empty foil area, and the first empty foil area is connected with the second empty foil area.

2. The battery of claim 1, wherein the first empty foil region is disposed at an end of the first negative electrode sheet or the first positive electrode sheet that is away from a winding center of the first winding core; and/or the number of the groups of groups,

the second empty foil area is arranged at one end of the second negative electrode plate or the second positive electrode plate, which is far away from the winding center of the second winding core.

3. The battery of claim 1, wherein the first empty foil area and the second empty foil area are at least partially overlapping.

4. The battery of claim 1, wherein an insulating layer is provided at least in the outer sidewall region where the first and second winding cores are in contact or adjacent.

5. The battery of claim 4, wherein the insulating layer is a gummed paper or a ceramic layer.

6. The battery of any of claims 1-5, wherein the winding direction of the first winding core is the same as the winding direction of the second winding core.

7. The battery of claim 6, wherein the first and second winding cores each have an oval cross-section;

the length of the first empty foil area is L1, the long axis of the first winding core is A1, the short axis of the first winding core is B1, A1-B1 is less than or equal to L1 and less than or equal to 2 (A1-B1); and/or the number of the groups of groups,

the length of the second empty foil area is L2, the long axis of the second winding core is A2, the short axis of the second winding core is B2, A2-B2 is less than or equal to L2 and less than or equal to 2 (A2-B2).

8. The battery of any of claims 1-5, wherein the winding direction of the first winding core is opposite to the winding direction of the second winding core.

9. The battery of claim 8, wherein the first and second winding cores each have an oval cross-section;

the length of the first empty foil area is L1, the long axis of the first winding core is A1, the short axis of the first winding core is B1, A1+B1 is less than or equal to L1 and less than or equal to 2 (A1+B1); and/or the number of the groups of groups,

the length of the second empty foil area is L2, the long axis of the first winding core is A2, the short axis of the first winding core is B2, A2+B2 is less than or equal to L2 and less than or equal to 2 (A2+B2).

10. The battery according to any one of claims 1 to 5, wherein the winding start position of the first winding core is on the first negative electrode sheet or the first positive electrode sheet;

and/or the winding starting position of the second winding core is on the second negative plate or the second positive plate.

11. The battery according to any one of claims 1 to 5, wherein one of the first positive electrode sheet and the first negative electrode sheet where the first empty foil region is not provided is provided with at least one first foil guiding portion protruding in the width direction thereof.

12. The battery of claim 11, wherein all of the first lead foil portions are connected to a first tab.

13. The battery according to any one of claims 1 to 5, wherein one of the second positive electrode sheet and the second negative electrode sheet where the second empty foil region is not provided is provided with at least one second foil guiding portion protruding in the width direction thereof.

14. The battery of claim 13, wherein all of the second lead foil portions are connected to second tabs.

15. The battery according to any one of claims 1 to 5, wherein one of the first positive electrode sheet and the first negative electrode sheet, which is not provided with the first empty foil region, is provided with a third empty foil region to which a first tab is connected, the third empty foil region being located at one end of the first positive electrode sheet or the first negative electrode sheet adjacent to the winding center of the first winding core; and/or the number of the groups of groups,

one of the second positive electrode plate and the second negative electrode plate, which is not provided with the second empty foil area, is provided with a fourth empty foil area, the fourth empty foil area is connected with a second lug, and the fourth empty foil area is positioned at one end of the second positive electrode plate or the second negative electrode plate, which is adjacent to the winding center of the second winding core.