CN219677330U

CN219677330U - Winding type battery cell and electric equipment

Info

Publication number: CN219677330U
Application number: CN202320630428.9U
Authority: CN
Inventors: 杜娟; 高云雷; 于子龙; 郑明清
Original assignee: Zhejiang Liwei Energy Technology Co ltd
Current assignee: Zhejiang Liwei Energy Technology Co ltd
Priority date: 2023-03-28
Filing date: 2023-03-28
Publication date: 2023-09-12
Anticipated expiration: 2033-03-28

Abstract

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a winding type battery cell and electric equipment, which comprises a battery cell body formed by sequentially stacking and winding a positive electrode plate, an isolating film and a negative electrode plate, wherein the battery cell body comprises a straight area and corner areas positioned at two ends of the straight area, the straight area is provided with a first coating, the corner areas are provided with a second coating, the second coating comprises an upper coating and a lower coating which are overlapped up and down, the thickness of the first coating is smaller than or equal to the total thickness of the second coating, the adhesive force of the upper coating is smaller than or equal to the lower coating, the surface density of the upper coating is smaller than or equal to the lower coating, and the extrusion of the expansion of the electrode plates at the corner areas to the corner areas is slowed down by increasing the gaps among particles at the corner areas, so that the wetting and reflux of electrolyte at the corner areas are increased, thereby improving the corner interfaces, reducing the generation of corner lithium precipitation phenomenon, and simultaneously enhancing the safety and the cycle performance of the battery cell body.

Description

Winding type battery cell and electric equipment

Technical Field

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a winding type battery cell and electric equipment.

Background

The lithium ion battery has the advantages of high capacity, large working voltage, long cycle life, environmental friendliness and the like, and is widely applied to products such as mobile phones, notebook computers, digital codes and the like. With the improvement of portable demands of people on travel, higher demands are also put on the performance of lithium ion batteries, and the lithium ion batteries are expected to have higher charging speed, higher cycle life and higher capacity.

The existing lithium ion battery adopts a structure that an anode pole piece, a cathode pole piece and an isolating film are wound, an outer ring is an anode pole piece wrapping cathode, an inner ring is a cathode pole wrapping cathode, the influence of a battery core body is avoided, extrusion received at a corner is large, the requirements on the laminating degree between the cathode and the anode are higher along with the improvement of the charging multiplying power, the interface gap between the anode and the cathode of the outer ring is further reduced, particularly, the expansion extrusion corner area of the cathode and the anode after long circulation is easy to generate ion bridge cutoff, black spots are caused to separate lithium, the side edge of the battery core is deformed, the side edge of the battery core is increased, and the safety and the circulation performance of the battery core are influenced.

Disclosure of Invention

The utility model aims at: aiming at the defects of the prior art, a winding type battery cell is provided to solve the problems that the existing lithium battery corner is extruded and lithium is easy to separate out, thereby influencing the safety and the cycle performance of a battery cell body.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

a winding type battery cell comprises a battery cell body formed by sequentially stacking and winding a positive electrode plate, a separation film and a negative electrode plate, wherein the battery cell body comprises a flat region and corner regions positioned at two ends of the flat region,

the straight area is provided with a first coating, the corner area is provided with a second coating, the second coating comprises an upper coating and a lower coating which are overlapped up and down, the thickness of the first coating is smaller than or equal to the total thickness of the second coating, the adhesion force of the upper coating is smaller than or equal to that of the lower coating, and the surface density of the upper coating is smaller than or equal to that of the lower coating.

As a preferred embodiment of the present utility model, the length d1 of the straight region is equal to or greater than the arc length d2 of the corner region, and satisfies the relationship 0.2.ltoreq.d1-d2.ltoreq.2.

As a preferred embodiment of the present utility model, the relationship between the first coating thickness h1 and the second coating thickness h2 is: h2/h1 is more than or equal to 1 and less than or equal to 1.5.

As a preferred embodiment of the utility model, the thickness h3 of the upper coating is smaller than the thickness h4 of the lower coating, wherein 1 < h4/h 3.ltoreq.15.

As a preferred embodiment of the present utility model, the upper coating area adhesion AF1 is smaller than the lower coating adhesion AF2 and is also smaller than the first coating adhesion AF3; and satisfies the relationship: AF1 is more than AF2 and less than or equal to AF3; the viscosity of the first coating is 3-10N/m; the viscosity of the coating on the second coating is 2-4N/m; wherein upper layer adhesion viscosity-lower coating adhesion range: 1-8N/m.

As a preferred embodiment of the present utility model, the upper coating layer has an areal density ρ2 smaller than that of the lower coating layer region ρ1 and smaller than that of the first coating layer ρ3, and satisfies the relationship: ρ2 < ρ1 is less than or equal to ρ3; the first coating areal density ρ1 and the second coating areal density ρ2 satisfy the relation: 1.02.ltoreq.ρ1/ρ2.ltoreq.3 and 1.0.ltoreq.ρ3/ρ1.ltoreq.1.5.

As a preferred embodiment of the present utility model, the barrier film comprises a base film and a coating layer, the base film mainly comprising: polyethylene, polypropylene, polyvinylidene fluoride or polyolefin materials and modified or multi-layer composite diaphragms thereof.

As a preferred embodiment of the utility model, the coating is PVDF, PMMA, ceramic material.

As a preferred embodiment of the present utility model, the upper and lower coating layers may be the same material or different materials.

The utility model also provides electric equipment, which comprises the winding type battery cell.

The utility model has the beneficial effects that the winding type battery cell comprises a battery cell body formed by sequentially stacking and winding a positive pole piece, a separation film and a negative pole piece, wherein the battery cell body comprises a straight area and corner areas positioned at two ends of the straight area, the straight area is provided with a first coating, the corner areas are provided with a second coating, the second coating comprises an upper coating and a lower coating which are overlapped up and down, the thickness of the first coating is smaller than or equal to the overall thickness of the second coating, the adhesive force of the upper coating is smaller than or equal to the lower coating, and the surface density of the upper coating area is smaller than or equal to the lower coating area. Through the clearance between the pole pieces in the corner area is increased, the extrusion of the pole pieces in the corner area to the corner area is slowed down, and the infiltration and the reflux of electrolyte in the corner area are increased, so that the corner interface is improved, the generation of lithium precipitation in the corner is reduced, and the safety and the cycle performance of the battery cell body are enhanced.

Drawings

Features, advantages, and technical effects of exemplary embodiments of the present utility model will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the overall structure of a coiled cell according to the present utility model;

fig. 2 is a schematic view of a partial structure of a separator for a lithium battery according to the present utility model.

Wherein reference numerals are as follows:

1. a cell body; 10. a flat region; 20. corner regions; 30. a negative electrode plate; 40. a separation film; 50. a positive electrode sheet; 60. a base film; 70. a first coating; 80. a second coating; 110. a first flat portion; 120 a second flat portion; 801. a lower coating layer; 802. and (5) coating.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model; the terms "comprising" and "having" and any variations thereof in the description of the utility model and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present utility model, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present utility model, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the utility model. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present utility model, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a alone, both a and B, and a plurality of cases alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of the embodiments of the present utility model, the term "plurality" means two or more (including two), and similarly, "plural sets" means two or more (including two), and "plural sheets" means two or more (including two).

In the description of the embodiments of the present utility model, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present utility model.

In the description of the embodiments of the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like should be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may 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 embodiments of the present utility model will be understood by those of ordinary skill in the art according to specific circumstances.

The present utility model will be described in further detail below with reference to fig. 1 to 2, but is not limited thereto.

The following describes an embodiment in connection with fig. 1 and 2;

a winding type battery cell comprises a battery cell body formed by sequentially stacking and winding a positive electrode plate 50, a separation film 40 and a negative electrode plate 30, wherein the battery cell body comprises a straight region 10 and corner regions 20 positioned at two ends of the straight region 10,

the flat region 10 is provided with a first coating 70, the corner region 20 is provided with a second coating 80, the second coating 80 comprises an upper coating 802 and a lower coating 801 which are stacked one on top of the other, the thickness of the first coating 70 is smaller than or equal to the total thickness of the second coating 80, the adhesion force of the upper coating 802 is smaller than or equal to the lower coating 801, and the surface density of the upper coating 802 is smaller than or equal to the lower coating 801.

As a preferred embodiment of the present utility model, the length d1 of the flat region 10 is equal to or greater than the arc length d2 of the corner region 20, and satisfies the relationship 0.2.ltoreq.d1-d2.ltoreq.2.

As a preferred embodiment of the present utility model, the relationship between the thickness h1 of the first coating 70 and the thickness h2 of the second coating 80 is: h2/h1 is more than or equal to 1 and less than or equal to 1.5.

As a preferred embodiment of the present utility model, the thickness h3 of the coating 802 on the second coating 80 is less than the thickness h4 of the small coating, where 1 < h4/h 3.ltoreq.15.

As a preferred embodiment of the present utility model, the bonding force AF1 of the upper coating 802 of the second coating 80 is smaller than the bonding force AF2 of the lower coating 801 of the second coating 80 and smaller than the bonding force AF3 of the first coating 70; and satisfies the relationship: AF1 is more than AF2 and less than or equal to AF3; the viscosity of the first coating layer 70 is 3-10N/m; the viscosity of the coating 802 on the second coating 80 is 2-4N/m; wherein the upper layer adhesion viscosity of the second coating 80-lower coating 801 adhesion range of the second coating 80: 1-8N/m.

As a preferred embodiment of the present utility model, the areal density ρ2 of the coating 802 on the second coating 80 is less than the areal density ρ3 of the first coating 70 while the coating 801 ρ1 under the second coating 80, and satisfies the relationship: ρ2 < ρ1 is less than or equal to ρ3; the first coating 70 areal density ρ1 and the second coating 80 areal density ρ2 satisfy the relation: 1.02.ltoreq.ρ1/ρ2.ltoreq.3 and 1.0.ltoreq.ρ3/ρ1.ltoreq.1.5.

As a preferred embodiment of the present utility model, the barrier film 40 includes a base film 60 and a coating layer, and the base film 60 is mainly: polyethylene, polypropylene, polyvinylidene fluoride or polyolefin materials and modified or multi-layer composite diaphragms thereof.

As a preferred embodiment of the utility model, the coating material is PVDF, PMMA, ceramic material.

The ceramic material is one of hydrated alumina, magnesia, silicon carbide and silicon nitride, the binder is one or a combination of more of polyvinylidene fluoride, polyacrylate, methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate, and the solvent is N-methyl pyrrolidone. The ceramic material is hydrated alumina, and the binder is polyvinylidene fluoride.

As a preferred embodiment of the present utility model, the first coating 70 and the second layer upper coating 802 and the lower coating 801 may be the same material or different materials.

In the implementation of the utility model, the battery cell body 1 is formed by sequentially stacking and winding the positive electrode plate 50, the isolating film 40 and the negative electrode plate 30, and the battery cell body 1 manufactured by winding is elliptic cylindrical; the positive electrode lug and the negative electrode lug are connected with the corresponding positive electrode pole piece 30, the positive electrode lug and the negative electrode pole piece 30 are connected in the modes of riveting, welding, punching and tapping, the pole piece and the positive electrode pole piece 30 are connected by using screws after the positive electrode lug and the negative electrode pole piece are drilled and tapped, the mechanical connection strength is high, firmness and low cost are realized, but the mode has a certain risk in operation, the pole piece and the pole piece are welded by using common welding materials after being drilled and tapped, the mode is simple in equipment, convenient to operate and low in cost, the reliability of welding the pole piece and the pole piece is low, the pole piece and the pole piece are easy to fall off, particularly when a battery is collided, the mode is also commonly used to adopt M51 welding wires (low-temperature welding wires) and low-temperature copper-aluminum welding, the mode is simple to operate, the welding performance is strong, the pole piece is difficult to fall off, and the defect is that the cost is too high.

Wherein the middle part of the battery cell body 1 is a straight area 10, and the corners at two sides of the battery cell body 1 are corner areas 20;

the flat region 10 is divided into a first flat portion 110 and a second flat portion 120, and the corner region 20 connects the first flat portion 110 and the second flat portion 120 of the flat region 10 in a semicircular structure.

The first coating 70 is then applied to the flat region 10 and the second coating 80 is applied to the corner region 20;

the second coating 80 also includes an upper coating 802 and a lower coating 801 that are superimposed one on top of the other;

in the practice of the present utility model, both the first coating 70 and the second coating 80 of the present utility model are coated with PVDF material.

In this embodiment, PVDF material is coated only on the separator, but PMMA, ceramic, or other materials may be used in addition to this embodiment, and this is not a limitation.

In the practice of the present utility model, the areal density of the material-coated areas of the first coating 70 is greater than the areal density of the material-coated areas of the second coating 80.

In practice, by changing the ratio of the areal density between the coating materials of the first coating 70 and the second coating 80, the gaps between the particles of the corner region 20 are changed, the extrusion of the corner region 20 by the expansion of the pole pieces of the corner region 20 due to heat generated during operation is slowed down, and the infiltration and backflow of the electrolyte in the corner region 20 are increased.

Compared with the prior art, the utility model uses the positive and negative pole pieces 30 after changing the surface density ratio between two image layer areas, the positive and negative pole pieces 30 are overlapped and wound to obtain the battery core body 1, the battery generates heat during operation, the battery core body 1 absorbs heat and slightly expands, and the expansion of the battery core body 1 does not have great influence on the corner areas 20 due to the increase of the gaps between particles in the corner areas 20 on the two sides of the battery core body 1, so that the lithium precipitation phenomenon of the corner areas 20 of the battery core body 1 can be effectively controlled.

The utility model also provides electric equipment, which comprises the positive electrode plate 50, the negative electrode plate 30, the isolating film 40 and electrolyte.

The positive electrode sheet 50 includes a base film 60 and an active material layer coated on the base film 60. Likewise, the negative electrode tab 30 also includes a base film 60 and an active material layer coated on the base film 60. Positive electrode sheet 50 and negative electrode sheet 30 may typically be continuous double-sided sheets. By "continuous" is meant herein that the active material layer of the pole piece is continuously coated on the base film 60 of the pole piece. "double sided" here means that both sides of the base film 60 of the pole piece are coated with an active material layer.

The positive pole piece, the isolating film and the negative pole piece are wound in the same direction to obtain the battery core body, and the battery core body can be realized by means of the winding needle. The positive electrode sheet 50, the negative electrode sheet 30, and the separator are stacked together, a winding needle is placed at a winding start end, and then winding is performed around the winding needle, thereby forming a stacked structure in which the positive electrode sheet 50 and the negative electrode sheet 30 are alternately stacked on each other and spaced apart by the separator. After the winding is completed, the winding needle may be withdrawn. In the case of winding by means of a winding needle, the winding axis is usually located on the winding needle.

The difference in areal density between the first coating 70 and the second coating 80 of the above-described embodiments will be demonstrated experimentally as follows: positive electrode sheet 50: active material lithium cobaltate, conductive agent acetylene black, conductive carbon nano tube and binder polyvinylidene fluoride (PVDF) are mixed according to the weight ratio of 97.6:0.5:0.6:1.3 fully and uniformly dispersing in an N-methyl pyrrolidone solvent system, coating the mixture on a base film 60, and then carrying out cold pressing and stripping to obtain the positive electrode sheet 50.

Negative electrode sheet 30: negative electrode active material, sodium carboxymethyl cellulose (CMC) dry powder, styrene Butadiene Rubber (SBR) emulsion were mixed according to 97.7:1.1:1.2, fully mixing in deionized water to form uniformly dispersed cathode slurry; the negative electrode sheet 30 is formed by coating the negative electrode sheet 30 on a copper foil base film 60, and then cold pressing and slitting are carried out to obtain the negative electrode sheet 30.

The separator 40: the first coating 70 of the PE surface is coated with an oil-based PVDF, the second coating 80 is coated with an aqueous PMMA, and the thickness of the first coating 70 is equal to that of the second coating 80 as the barrier film 40, the second coating 80 is coated with an aqueous PMMA, and the lower coating 801 is coated with an oil-based PVDF as the barrier film, and the coating structure is shown in fig. 2.

Electrolyte solution: ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC) and Propyl Propionate (PP) are mixed according to the volume ratio of 1:1:4:4: the mixture was then dissolved in a mixed organic solvent at a ratio of 1 mol/L to prepare an electrolyte.

Full cell preparation: the positive electrode sheet 50, the isolating film 40 and the negative electrode sheet 30 are wound to manufacture the battery core body 1, and then the battery core body is packaged and injected with electrolyte to manufacture the finished lithium battery.

The batteries of examples 2 to 4 and comparative examples 1 to 2 were each prepared in a similar manner to example 1, and are specifically shown in table 1. Table 1 shows the design parameters of the release film 40 for all examples and comparative examples.

TABLE 1

Corner lithium analysis is performed when the battery cell is charged to 4.3V in a 3C step, the conversion rate is 1.8C, the battery cell is charged to a cut-off voltage, the battery cell is cycled for 100 times, the design parameters of the embodiment and the comparative example shown in the table 1 are used for disassembling the interface of the battery cell after the battery cell is cycled, the following results are obtained according to the table 1:

TABLE 2

Case (B)	Corner lithium evolution condition
		Example 1	Without any means for
Example 2	Without any means for
		Example 3	Without any means for
Example 4	Without any means for
		Example 5	Without any means for
Example 6	Without any means for
		Comparative example 1	Severe lithium precipitation
Comparative example 2	Slightly precipitating lithium

Corner lithium precipitation prevention: the corner of the negative electrode plate 30 is free of lithium;

slight corner lithium evolution: lithium is separated out from the corner of the negative electrode plate 30, but the negative electrode plate is not connected with the lithium separating plate;

serious corner lithium precipitation: lithium is separated out from the corners of the negative electrode plate 30, and the separated lithium is connected with the plate.

It can be seen that when the second coating surface density of the separator 40 is less than the first coating surface density, the corner lithium precipitation condition can be significantly improved, mainly because the second coating surface density is reduced when the second coating thickness is consistent with the first coating thickness, the gap between particles in the corner region 20 is increased, the extrusion of the pole piece expansion in the corner region 20 to the corner region 20 is slowed down, the wetting and reflux of the electrolyte in the corner region 20 are increased, the corner interface is improved, the corner lithium precipitation generation is reduced, and the utility model only optimizes the corner position without significantly affecting the overall performance of the battery cell.

A process for preparing the battery as described above is briefly described below.

Firstly, the anode or cathode powder and other ingredients are stirred and mixed uniformly, and the mixture is prepared into slurry.

The fully stirred and uniform slurry is coated on the surface of the base film 60 according to actual conditions, (the flat area 10 and the corner area 20 of the cell body 1 are determined by calculating the size and the length of the final finished cell, the corner area 20 is coated again by other methods such as asynchronous coating or manual coating, or the thickness, the density and the like of the flat area 10 and the corner area 20 are coated in a different manner in the first coating process, the solvent in the slurry paved on the base film 60 is removed by drying and heating, so that solid matters are well adhered to the base film 60, and the base film 60 is dried to be manufactured into a positive electrode coil sheet and a negative electrode coil sheet respectively.

And compacting the dried positive and negative pole piece 30 rolls to reach proper density and thickness.

The compacted roll of pole pieces is then slit into large pieces and then subdivided into the desired rolls of small positive and negative pole pieces 30.

The positive electrode sheet 50, the isolating film 40 and the negative electrode sheet 30 are sequentially stacked, and then the stacked materials are wound in the same direction to form the battery core body 1, and the winding mode can be realized by means of a winding needle. The positive electrode sheet 50, the negative electrode sheet 30, and the separator are stacked together, a winding needle is placed at a winding start end, and then winding is performed around the winding needle, thereby forming a stacked structure in which the positive electrode sheet 50 and the negative electrode sheet 30 are alternately stacked on each other and spaced apart by the separator. After the winding is completed, the winding needle may be withdrawn. In the case of winding by means of a winding needle, the winding axis is usually located on the winding needle.

Packaging aluminum foil on the battery cell body 1, and thermally packaging the top and the side edges.

After drying and dewatering treatment is carried out inside the battery cell, electrolyte is added into the battery cell, and the battery cell is completely sealed.

Finally, the battery is obtained through ageing, trimming, flanging and other processes.

The cell corner regions 20 in the present cell have a lower areal density and viscosity than the cell flat regions 10, but the opposite corner regions have a greater porosity than the flat regions, and the present utility model can be achieved by the above cell preparation method.

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 embodiments of the disclosure may be suitably combined to form other embodiments as will be understood by those skilled in the art.

Variations and modifications of the above embodiments will occur to those skilled in the art to which the utility model pertains from the foregoing disclosure and teachings. Therefore, the present utility model is not limited to the above-described embodiments, but is intended to be capable of modification, substitution or variation in light thereof, which will be apparent to those skilled in the art in light of the present teachings. In addition, although specific terms are used in the present specification, these terms are for convenience of description only and do not limit the present utility model in any way.

Claims

1. The utility model provides a coiling formula electricity core, includes the electricity core body that is formed by positive pole piece, barrier film and negative pole piece stack gradually winding, the electricity core body includes straight district and is located the corner district at straight district both ends, its characterized in that:

the flat area is provided with a first coating, the corner area is provided with a second coating, the second coating comprises an upper coating and a lower coating which are overlapped up and down, the thickness of the first coating is smaller than or equal to the total thickness of the second coating, the bonding force of the upper coating is smaller than or equal to that of the lower coating, and the surface density of the upper coating is smaller than or equal to that of the lower coating.

2. The coiled electrical cell of claim 1, wherein: the length d1 of the straight area is larger than or equal to the arc length d2 of the corner area, and the relation of d1-d2 is more than or equal to 0.2 and less than or equal to 2.

3. The coiled electrical cell of claim 1, wherein: the relation between the first coating thickness h1 and the second coating thickness h2 is as follows: h2/h1 is more than or equal to 1 and less than or equal to 1.5.

4. The coiled electrical cell of claim 1, wherein: the thickness h3 of the upper coating is smaller than the thickness h4 of the lower coating, wherein h4/h3 is more than 1 and less than or equal to 15.

5. The coiled electrical cell of claim 1, wherein: the upper coating area bonding force AF1, the lower coating bonding force AF2 and the first coating bonding force AF3; the relation is satisfied: AF1 is more than AF2 and less than or equal to AF3; the viscosity of the first coating is 3-10N/m; the viscosity of the coating on the second coating is 2-4N/m; wherein the upper coating adhesion viscosity-the lower coating adhesion range: 1-8N/m.

6. The coiled electrical cell of claim 1, wherein: the surface density ρ2 of the upper coating layer, the lower coating layer region ρ1, and the first coating layer surface density ρ3 satisfy the relation: ρ2 < ρ1 is less than or equal to ρ3; the first coating area density ρ1 and the second coating area density ρ2 satisfy the relation: 1.02.ltoreq.ρ1/ρ2.ltoreq.3 and 1.0.ltoreq.ρ3/ρ1.ltoreq.1.5.

7. The coiled electrical cell of claim 1, wherein: the isolating film comprises a base film and a coating, wherein the base film mainly comprises: polyethylene, polypropylene, polyvinylidene fluoride or polyolefin material and modification or modification thereof

A multilayer composite separator.

8. The coiled electrical cell of claim 1, wherein: the coating is PVDF, PMMA and ceramic material.

9. The coiled electrical cell of claim 1, wherein: the upper coating and the lower coating are the same substance or a plurality of different substances.

10. An electrical consumer, characterized in that: comprising a wound cell according to any one of claims 1 to 9.