阅读说明：本技术 电池以及应用所述电池的电子装置 (Battery and electronic device using same ) 是由 陈晓 张远兵 胡克文 石长川 于 2020-12-24 设计创作，主要内容包括：一种电池,包括电极组件和封装所述电极组件的封装膜,所述电极组件包括第一极片、第二极片和隔膜,所述隔膜设置于所述第一极片和所述第二极片之间,所述隔膜与所述第一极片或所述第二极片之间的粘结力≥3N/m,所述电池还包括胶粘层,所述胶粘层设置于所述电极组件的表面与所述封装膜之间并将所述电极组件与所述封装膜粘结在一起。本申请有利于提高安全性及电池能量密度。本申请还提供一种应用上述电池的电子装置。(A battery comprises an electrode assembly and an encapsulation film for encapsulating the electrode assembly, wherein the electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, the diaphragm is arranged between the first pole piece and the second pole piece, the adhesive force between the diaphragm and the first pole piece or the second pole piece is not less than 3N/m, the battery also comprises an adhesive layer, and the adhesive layer is arranged between the surface of the electrode assembly and the encapsulation film and bonds the electrode assembly and the encapsulation film together. The application is beneficial to improving the safety and the energy density of the battery. The application also provides an electronic device using the battery.)

1. A battery comprises an electrode assembly and an encapsulation film for encapsulating the electrode assembly, and is characterized in that the electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, the diaphragm is arranged between the first pole piece and the second pole piece, the adhesive force between the diaphragm and the first pole piece or the second pole piece is not less than 3N/m, the battery further comprises an adhesive layer, and the adhesive layer is arranged between the surface of the electrode assembly and the encapsulation film and bonds the electrode assembly and the encapsulation film together.

2. The battery according to claim 1, wherein the adhesive layer has an adhesive force of 3N/m to 1000N/m with respect to the encapsulation film.

3. The battery according to claim 1, wherein the adhesive layer has a bonding force between 3N/m and 1000N/m with respect to the surface of the electrode assembly.

4. The battery of claim 1, wherein the adhesion between the separator and the first or second pole piece is 3N/m to 30N/m.

5. The battery of claim 1, wherein the adhesive layer has a thickness of 1 μm to 20 μm.

6. The battery according to claim 1, wherein an area where the surface of the electrode assembly is bonded to the adhesive layer accounts for 20% to 100% of a total area of the surface of the electrode assembly.

7. The battery of claim 1, wherein the adhesive layer comprises at least one of a polyolefin, an epoxy, a silicone, or an acrylate.

8. The battery according to claim 1, wherein the adhesive layer is provided on the surface of the electrode assembly, and the shape of the adhesive layer includes at least one of a block shape, a dot shape, or a linear shape.

9. The battery of claim 1, wherein the separator comprises a porous substrate and a bonding layer disposed on a surface of the porous substrate, wherein a side of the bonding layer facing away from the porous substrate is bonded to the first or second pole piece.

10. The battery of claim 9, wherein the tie layers are disposed on opposite surfaces of the porous substrate.

11. An electronic device, characterized in that the electronic device comprises a battery according to any of claims 1-10.

Technical Field

The present disclosure relates to a battery, and more particularly to a battery and an electronic device using the same.

Background

With the mature application of consumer electronics, customers pay more and more attention to the risk of the whole machine application. For example, the drop resistance of electronic products is increasingly required. The battery, as an important component of electronic products, also has a requirement for drop resistance.

When the battery falls along with the electronic product, the electrode assembly contained in the battery packaging film is easy to move in the packaging film. When the electrode assembly moves in the packaging film, the diaphragm positioned at the head part of the electrode assembly provided with the pole lugs and the tail part opposite to the head part is easy to pleat or shrink, so that the cathode pole piece and the anode pole piece are in direct contact, the electrode assembly is short-circuited, and the safety of the battery is further influenced. Therefore, it is generally required to attach a winding adhesive to the head and the tail of the electrode assembly to fix the separator. However, the winding adhesive increases the thickness of the battery, resulting in a decrease in the volumetric energy density of the battery.

Disclosure of Invention

In view of the above, it is necessary to provide a battery advantageous for improving safety and energy density.

In addition, there is a need to provide an electronic device using the above battery.

A battery of the present application includes an electrode assembly and an encapsulation film encapsulating the electrode assembly. The electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, wherein the diaphragm is arranged between the first pole piece and the second pole piece, and the adhesive force between the diaphragm and the first pole piece or the second pole piece is more than or equal to 3N/m. The battery further includes an adhesive layer disposed between the surface of the electrode assembly and the encapsulation film and bonding the electrode assembly and the encapsulation film together.

As a scheme of the application, the bonding force between the adhesive layer and the packaging film is 3N/m to 1000N/m.

As one aspect of the present application, the adhesive force between the adhesive layer and the surface of the electrode assembly is 3N/m to 1000N/m.

As one scheme of the application, the adhesion force between the diaphragm and the first pole piece or the second pole piece is 3N/m to 30N/m.

As one aspect of the present application, the thickness of the adhesive layer is 1 μm to 20 μm, which is advantageous for reducing the overall thickness of the battery while securing the adhesive force, thereby reducing the influence on the energy density of the battery.

As one aspect of the present application, an area where the surface of the electrode assembly is bonded to the adhesive layer occupies 20% to 100% of the area of the surface of the electrode assembly, thereby further securing the stability of the bonding between the electrode assembly and the encapsulation film.

As an aspect of the present application, the adhesive layer includes at least one of polyolefin, epoxy resin, silicone, or acrylate.

As an aspect of the present application, the adhesive layer is disposed on the surface of the electrode assembly, and a shape of the adhesive layer includes at least one of a block shape, a dot shape, or a linear shape.

As a scheme of this application, the diaphragm includes the diaphragm substrate and set up in the tie coat on the surface of diaphragm substrate, the tie coat deviates from one side of diaphragm substrate with first pole piece or second pole piece bonds.

As a scheme of this application, the tie coat set up in two surfaces that carry on the back of the diaphragm substrate mutually, be favorable to further reducing the risk of the short circuit of first pole piece with the second pole piece.

The application also provides an electronic device, which comprises the battery.

This application is through set up high viscidity diaphragm in the battery for diaphragm and first pole piece or second pole piece bond closely, work as the battery is receiving the exogenic action, the diaphragm is difficult for pleating or shrink, and then can avoid electrode subassembly short circuit for the battery possesses higher anti falling performance, has reduced the possibility that the battery became invalid when receiving the impact has improved the security of battery. Meanwhile, the adhesive layer bonds the electrode assembly and the packaging film together, so that the situation that the electrode assembly moves in the packaging film and even breaks the packaging film when the battery is subjected to external force is reduced, and the falling resistance and the safety of the battery are further improved. Namely, the high-viscosity separator and the adhesive layer act together, so that the battery has high drop resistance and safety. On the other hand, the winding glue at the head and the tail of the electrode assembly is eliminated, so that the thickness of the battery is reduced, and the energy density of the battery is improved.

Drawings

Fig. 1 is a schematic structural diagram of a battery according to an embodiment of the present application.

Fig. 2 is a disassembled schematic view of a battery according to an embodiment of the present application.

Fig. 3 is a schematic structural view of an electrode assembly provided with an adhesive layer according to an embodiment of the present application.

Fig. 4 is a schematic structural view of an electrode assembly provided with an adhesive layer according to an embodiment of the present application.

Fig. 5 is a schematic cross-sectional view of an electrode assembly provided with an adhesive layer according to an embodiment of the present application.

Fig. 6 is a partial cross-sectional view of an electrode assembly according to an embodiment of the present application.

Fig. 7 is a partial cross-sectional view of an electrode assembly according to an embodiment of the present application.

Fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Description of the main elements

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

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 application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The features of the following examples/embodiments and examples/embodiments may be combined with each other without conflict.

Referring to fig. 1 and 2, the present embodiment provides a battery 100 including an electrode assembly 10 and an encapsulation film 30 encapsulating the electrode assembly 10.

The battery 100 further includes an adhesive layer 50, and the adhesive layer 50 is disposed between the surface of the electrode assembly 10 and the packaging film 30 and bonds the surface of the electrode assembly 10 and the packaging film 30, thereby reducing the possibility that the electrode assembly 10 moves in the packaging film 30 or even breaks the packaging film 30 when the battery 100 is subjected to external force, and thus reducing the possibility that the battery 100 fails when the battery 100 is subjected to impact.

Preferably, the adhesive force between the adhesive layer 50 and the encapsulation film 30 is 3N/m to 1000N/m, and the adhesive force between the adhesive layer 50 and the surface of the electrode assembly 10 is 3N/m to 1000N/m. Therefore, the electrode assembly 10 and the sealing film 30 are tightly adhered, thereby further preventing the electrode assembly 10 from moving in the sealing film 30 and even breaking the sealing film 30 when the battery 100 is subjected to an external force.

In some embodiments, the adhesive layer 50 may be selected from, but not limited to, polyolefins, epoxies, silicones, acrylates, or combinations thereof. Preferably, the adhesive layer 50 has a thickness of 1 μm to 20 μm, which is advantageous in reducing the overall thickness of the battery 100 while securing the adhesive force, thereby reducing the influence on the energy density of the battery 100.

The area where the surface of the electrode assembly 10 is bonded to the adhesive layer 50 accounts for 20% to 100% of the total area of the surface of the electrode assembly 10, thereby further securing the bonding stability between the electrode assembly 10 and the encapsulation film 30.

Referring to fig. 2, 3 and 4, on the surface of the electrode assembly 10, the adhesive layer 50 may have at least one of a block shape, a dot shape, a linear shape, and combinations thereof.

The electrode assembly 10 is of a winding type structure, and the surface of the electrode assembly 10 includes two main flat surfaces 101 arranged oppositely and two bending surfaces 103 connected with the two main flat surfaces 101 and arranged oppositely. Preferably, the adhesive layer 50 is disposed on the major plane 101.

Referring to fig. 5, the electrode assembly 10 includes a first pole piece 11, a second pole piece 13, and a separator 15. The diaphragm 15 is arranged between the first pole piece 11 and the second pole piece 13, and the adhesive force between the diaphragm 15 and the first pole piece 11 or the second pole piece 13 is more than or equal to 3N/m. This application sets up high viscidity diaphragm 15 in electrode subassembly 10 for diaphragm 15 and first pole piece 11 or second pole piece 13 bond closely, and when battery 100 when receiving the exogenic action, diaphragm 15 is difficult for pleating or shrink, and then avoids electrode subassembly 10 short circuit, makes battery 100 equally can have higher anti falling performance, has further improved battery 100's security. Therefore, the high-viscosity separator 15 and the adhesive layer 50 work together, so that the battery 100 has high drop resistance and safety. On the other hand, since the winding of the head and the tail of the electrode assembly 10 is eliminated, the increase in thickness of the battery 100 caused by fixing the separator 15 by winding is avoided, which is advantageous to improve the energy density of the battery 100.

Referring to fig. 6, the diaphragm 15 includes a diaphragm substrate 151 and an adhesive layer 153 disposed on a surface of the diaphragm substrate 151. The side of the adhesive layer 153 facing away from the diaphragm substrate 151 is adhered to the first or second pole piece 11, 13.

In some embodiments, as shown in fig. 6, the adhesive layer 153 is disposed on only one side of the diaphragm substrate 151 for adhesion with the first or second pole piece 11 or 13. In some embodiments, referring to fig. 7, the adhesive layers 153 may also be disposed on two opposite surfaces of the diaphragm substrate 151, and the adhesive layers 153 on the two opposite surfaces of the diaphragm substrate 151 are respectively adhered to the first pole piece 11 and the second pole piece 13, which is beneficial to further reduce the risk of short circuit of the first pole piece 11 and the second pole piece 13.

In some embodiments, the material of the separator substrate 151 may be at least one selected from Polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and the like. The separator substrate 151 may be a single layer structure or a multi-layer composite structure of various kinds mixed.

In some embodiments, the adhesive layer 153 may include a core-shell adhesive (not shown) including a core and a shell covering the core. The core and the shell are homopolymers or copolymers formed by polymer monomers, and the polymer monomers forming the core comprise at least one of acrylate monomers, aromatic monovinyl compounds, monocarboxylic acid anhydrides or dicarboxylic acid anhydrides. Acrylate monomers include, but are not limited to, ethyl acrylate, butyl acrylate, and ethyl methacrylate. Aromatic monovinyl compounds include, but are not limited to, styrene, chlorostyrene, fluorostyrene, and methylstyrene.

The polymer monomer forming the shell includes at least one of an acrylate monomer, an aromatic monovinyl compound, or a cyanated vinyl compound. Acrylate monomers include, but are not limited to, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Aromatic monovinyl compounds include, but are not limited to, ethylene, chlorostyrene, fluorostyrene, and methylstyrene. The vinyl cyanated compounds include, but are not limited to, acrylonitrile and methacrylonitrile.

In other embodiments, the adhesive layer 153 may be formed of a non-core-shell structured adhesive including a homopolymer or copolymer formed from a polymer monomer including at least one of vinylidene fluoride, hexafluoropropylene, acrylic acid, acrylate, butadiene, styrene, acrylonitrile, ethylene, chlorostyrene, fluorostyrene, or propylene.

In some embodiments, the adhesive layer 153 may further include an auxiliary binder, and the mass ratio of the binder to the auxiliary binder is (85% to 95%): (5% to 15%). The auxiliary binder includes at least one of homopolymers or copolymers of ethyl acrylate, butyl acrylate, ethyl methacrylate, styrene, chlorostyrene, fluorostyrene, methylstyrene, acrylic acid, methacrylic acid, maleic acid, acrylonitrile, and butadiene.

Further, the adhesive layer 153 may further contain a thickener and a wetting agent. The thickener is used for improving the stability of the slurry and preventing the slurry from settling. The wetting agent serves to reduce the surface energy of the slurry and prevent coating skip. Wherein, the mass of the binder accounts for 88 to 92.5 percent of the total mass of the bonding layer 153, the mass of the thickening agent accounts for 0.5 to 2 percent of the total mass of the bonding layer 153, and the mass of the wetting agent accounts for 7 to 10 percent of the total mass of the bonding layer 153. In some embodiments, the thickening agent may be sodium carboxymethylcellulose (CMC). The wetting agent comprises at least one of dimethyl siloxane, polyethylene oxide, ethylene oxide alkylphenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer or dioctyl sodium sulfosuccinate.

In some embodiments, the separator 15 may further include a ceramic coating (not shown) applied to the separator substrate 151. The bonding layer 153 is located on the surface of the ceramic coating and/or the surface of the diaphragm substrate 151 that is not coated with the ceramic coating. For example, the ceramic coating is disposed on one surface of the diaphragm substrate 151, the number of the bonding layers 153 is two, one bonding layer 153 is disposed on the surface of the ceramic coating, and the other bonding layer 153 is disposed on the surface of the diaphragm substrate 151 on which the ceramic coating is not disposed. Among other things, the ceramic coating is used to improve the heat resistance and puncture resistance of the separator 15. The ceramic coating is provided with nanoscale inorganic particles, and the inorganic ceramic particles can be selected from at least one of hydrated alumina (boehmite), alumina, silica, titanium oxide, cerium oxide, calcium carbonate, calcium oxide, zinc oxide, magnesium oxide, cerium titanate, calcium titanate, barium sulfate, lithium phosphate or lithium titanium phosphate.

In other embodiments, the diaphragm 15 may also be free of ceramic coatings. At this time, the adhesive layer 153 may further include nano-sized inorganic ceramic particles. By adding inorganic ceramic particles to the adhesive layer 153, the heat resistance and puncture resistance of the separator 15 can be improved as well.

Referring to fig. 8, the battery 100 is applied to an electronic device 200. The electronic device 200 may be, but is not limited to, a mobile phone, a toy, a notebook computer, an e-reader, etc.

The present application will be specifically described below by way of comparative examples and examples. It should be understood that the parameters in the present application are not limited to the contents described in the comparative examples and examples, and can be specifically selected according to actual needs.

Comparative example 1

Preparing a cathode plate: selecting 10-micron aluminum foil as a cathode current collector, and mixing lithium cobaltate, conductive carbon black and polyvinylidene fluoride according to a mass ratio of 97: 1.4: dissolving the mixture in N-methyl pyrrolidone (NMP) solvent according to the proportion of 1.6 to form cathode active slurry, coating the cathode active slurry on the surface of a cathode current collector, drying and cold-pressing to obtain the cathode pole piece.

Preparing an anode piece: selecting a copper foil with the thickness of 6 mu m as an anode current collector, and mixing graphite, conductive carbon black, CMC and Styrene Butadiene Rubber (SBR) according to the mass ratio of 96.5: 1.0: 1.0: dissolving the anode active slurry in deionized water according to the proportion of 1.5, stirring the mixture under the action of a vacuum stirrer until the system is uniform to obtain anode active slurry, coating the anode active slurry on the surface of an anode current collector, drying and carrying out cold pressing to obtain the anode piece.

Preparing a diaphragm: selecting 5 mu m Polyethylene (PE) as a diaphragm substrate, and coating a ceramic coating with the thickness of 2 mu m on one side of the diaphragm substrate, wherein the ceramic coating comprises boehmite with the particle size D50 of 0.8-1 mu m; adding 2 parts of acrylic copolymer into 100 parts of water, uniformly stirring, adding 35 parts of polyvinylidene fluoride (PVDF), adding 0.5 part of thickening agent sodium carboxymethyl cellulose (CMC), uniformly coating the slurry on a diaphragm base material and a ceramic coating respectively, and drying to obtain the diaphragm.

Preparation of electrode assembly: the cathode plate, the separator and the anode plate were sequentially laminated and wound to form a wound electrode assembly, and the wound electrode assembly was terminated with a double-sided hot-melt adhesive tape (as an adhesive layer to be bonded to an encapsulating film in subsequent encapsulation) having a length of 70mm, a width of 20mm and a thickness of 48 μm, with a bonding force between the hot-melt adhesive tape and the encapsulating film of 158.5N/m. And then respectively carrying out one-strip glue winding treatment on the head part provided with the lugs of the electrode assembly by adopting single-side hot melt adhesive with the length of 24mm and the thickness of 48 mu m, and carrying out two-strip glue winding treatment on the bottom part of the electrode assembly, which is opposite to the head part. Wherein, the adhesive force between the diaphragm and the cathode pole piece is 1.1N/m, and the adhesive force between the diaphragm and the anode pole piece is 0.4N/m.

Preparing a battery: and packaging, drying and injecting the electrode assembly through a packaging film, carrying out formation treatment for 40min at 80 ℃ and under the pressure of 1030kg/2ea, degassing, sealing and folding to obtain the battery. Wherein the adhesive layer bonds the encapsulation film and the electrode assembly.

Example 1

Preparing a cathode plate: the difference from comparative example 1 is that the adhesive layer was formed by coating polyolefin hot melt adhesive on the blank area of the tail of the pole piece prepared in comparative example 1 and drying, wherein the thickness of the adhesive layer was 1 μm.

Preparing an anode piece: same as in comparative example 1.

Preparing a diaphragm: selecting PE with the thickness of 5 mu m as a diaphragm substrate, and coating a ceramic coating with the thickness of 2 mu m on one side of the diaphragm substrate, wherein the ceramic coating comprises boehmite with the particle size D50 of 0.8-1 mu m; adding 91 wt% of binder into a stirrer, wherein the polymerization monomer of the binder comprises 0.8 part of styrene, 0.1 part of isobutyl acrylate and 0.1 part of acrylonitrile, then adding 0.5 wt% of thickener sodium carboxymethyl cellulose (CMC), then continuously adding 8.5 wt% of wetting agent dimethyl siloxane, finally adding deionized water, adjusting the viscosity of the slurry, then respectively and uniformly coating the slurry on the diaphragm substrate and the ceramic coating to form a bonding layer (with the thickness of 8.3 mu m), and drying through a drying oven to obtain the diaphragm.

Preparation of electrode assembly: and sequentially laminating the cathode pole piece, the diaphragm and the anode pole piece, winding to form a winding type electrode assembly, and ending by a green glue with the thickness of 10 mu m. After winding, the blank area of the cathode pole piece provided with the adhesive layer is used as the whole surface of the electrode assembly, and the bonding area of the surface of the electrode assembly and the adhesive layer accounts for 50% of the total area of the surface of the electrode assembly. The adhesive force between the diaphragm and the cathode pole piece is 3N/m, and the adhesive force between the diaphragm and the anode pole piece is 3N/m.

Preparing a battery: same as in comparative example 1.

Example 2

Preparing a cathode plate: the difference from example 1 is that the adhesive layer has a thickness of 6 μm.

Preparing an anode piece: same as in example 1.

Preparing a diaphragm: the difference from example 1 is that the polymerized monomers of the binder include 0.7 part of styrene, 0.2 part of isobutyl acrylate and 0.1 part of acrylonitrile.

Preparation of electrode assembly: the difference from example 1 was that the area where the surface of the electrode assembly was bonded to the adhesive layer accounted for 20% of the total area of the surface of the electrode assembly. The adhesive force between the diaphragm and the cathode pole piece is 9.1N/m, and the adhesive force between the diaphragm and the anode pole piece is 10.2N/m.

Preparing a battery: same as in example 1.

Example 3

Preparing a cathode plate: the difference from example 1 is that the adhesive layer has a thickness of 8 μm.

Preparing an anode piece: same as in example 1.

Preparing a diaphragm: the difference from example 1 is that the polymerized monomers of the binder include 0.6 part of styrene, 0.3 part of isobutyl acrylate and 0.1 part of acrylonitrile.

Preparation of electrode assembly: the difference from example 1 was that the area where the surface of the electrode assembly was bonded to the adhesive layer accounted for 40% of the total area of the surface of the electrode assembly. The adhesive force between the diaphragm and the cathode pole piece is 9.8N/m, and the adhesive force between the diaphragm and the anode pole piece is 10.6N/m.

Preparing a battery: same as in example 1.

Example 4

Preparing a cathode plate: the difference from example 1 is that the thickness of the adhesive layer was 10 μm.

Preparing an anode piece: same as in example 1.

Preparing a diaphragm: the difference from example 1 is that the polymerized monomers of the binder include 0.7 parts of propylene, 0.2 parts of isobutyl acrylate and 0.1 parts of acrylonitrile.

Preparation of electrode assembly: the difference from example 1 was that the area where the surface of the electrode assembly was bonded to the adhesive layer accounted for 80% of the total area of the surface of the electrode assembly. The adhesive force between the diaphragm and the cathode pole piece is 8.8N/m, and the adhesive force between the diaphragm and the anode pole piece is 9.8N/m.

Preparing a battery: same as in example 1.

Example 5

Preparing a cathode plate: the difference from example 1 is that the adhesive layer has a thickness of 15 μm.

Preparing an anode piece: same as in example 1.

Preparing a diaphragm: the difference from example 1 is that the polymerized monomers of the binder include 0.8 parts of propylene, 0.1 parts of acrylonitrile and 0.1 parts of acrylic acid.

Preparation of electrode assembly: the difference from example 1 was that the area where the surface of the electrode assembly was bonded to the adhesive layer accounted for 80% of the total area of the surface of the electrode assembly. The adhesive force between the diaphragm and the cathode pole piece is 9.5N/m, and the adhesive force between the diaphragm and the anode pole piece is 10.5N/m.

Preparing a battery: same as in example 1.

Example 6

Preparing a cathode plate: the difference from example 1 is that the adhesive layer has a thickness of 20 μm.

Preparing an anode piece: same as in example 1.

Preparing a diaphragm: same as in example 1.

Preparation of electrode assembly: the difference from example 1 was that the area where the surface of the electrode assembly was bonded to the adhesive layer accounted for 80% of the total area of the surface of the electrode assembly. The adhesive force between the diaphragm and the cathode pole piece is 3N/m, and the adhesive force between the diaphragm and the anode pole piece is 3N/m.

Preparing a battery: same as in example 1.

Comparative example 4

Preparing a cathode plate: same as in example 6.

Preparing an anode piece: same as in example 6.

Preparing a diaphragm: same as in comparative example 1.

Preparation of electrode assembly: the same as example 6, except that the adhesive force between the separator and the cathode plate was 1.1N/m, and the adhesive force between the separator and the anode plate was 0.4N/m.

Preparing a battery: same as in example 6.

The main parameters of comparative examples 1-2 and examples 1-6 are reported in table 1 below.

TABLE 1

The thickness measurements were performed on the batteries manufactured in comparative examples 1-2 and examples 1-6. Then, the batteries manufactured in comparative examples 1-2 and examples 1-6 were subjected to drop tests, and the corresponding drop results were recorded in table 2 below. 10 cells of each group of comparative examples or examples are tested, and the specific method of drop test is as follows: firstly, regulating the voltage of the battery to 100% SOC, and measuring the voltage and the internal resistance of the battery before dropping after charging and standing for 2 hours; sequentially placing a battery, a barrier strip and a silica gel pad into a fixture bin (an electrode assembly, the barrier strip and the silica gel pad), placing a 1mm silica gel pad on the surface of the battery, pressing for 12 hours by using a 5kg pressing block, and clamping an upper cover plate of the fixture bin; the clamp bin with the battery is dropped from the position of 1.5 meters in turn by automatic equipment dropping equipment in a mode that the head, the tail, the upper right corner, the lower right corner, the upper left corner and the lower left corner of the clamp bin are landed for one wheel, and the dropping is carried out for 3 wheels in total, namely 18 times. And measuring the voltage of the battery after each round of dropping, stopping dropping continuously when the battery is on fire, generates heat, leaks and has a voltage drop of more than or equal to 50mV, and finishing 3 rounds of dropping continuously if the battery is not on fire, generates heat, leaks and has a voltage drop of more than or equal to 50 mV. And taking out the battery after 3 times of dropping, standing the battery for 24 hours at normal temperature, and then measuring the voltage and the internal resistance of the battery. The measurement results are recorded in table 2 below.

TABLE 2

As can be seen from the table data, compared with comparative example 1, the batteries of examples 1 to 6 of the present application omit the winding of the adhesive on the head and bottom of the electrode assembly, and the highly adhesive separator is provided, so that the battery has a high drop resistance under the premise of reducing the overall thickness of the battery.

Comparing comparative example 2 and example 6, comparative example 2 and example 6 both provided polyolefin hot melt adhesives on the surface of the electrode assembly, however, the drop resistance of the battery of example 6 was greatly improved compared to comparative example 2, indicating that the provision of the highly adhesive separator in example 6 is the main reason for enabling the battery to maintain high drop resistance.

In addition, it is obvious to those skilled in the art that other various corresponding changes and modifications can be made according to the technical idea of the present application, and all such changes and modifications should fall within the protective scope of the present application.