WO2022133859A1

WO2022133859A1 - Battery and electronic apparatus using said battery

Info

Publication number: WO2022133859A1
Application number: PCT/CN2020/138848
Authority: WO
Inventors: 陈晓; 张远兵; 胡克文; 石长川
Original assignee: 宁德新能源科技有限公司
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2022-06-30
Also published as: CN113875083A

Abstract

A battery, which comprises an electrode assembly and an encapsulation film encapsulating the electrode assembly, the electrode assembly comprising a first electrode piece, a second electrode piece, and a separation membrane, the separation membrane being arranged between the first electrode piece and the second electrode piece, and a bonding force ≥ 3 N/m being present between the separation membrane and the first electrode piece or the second electrode piece; the battery further comprises an adhesive layer, the adhesive layer is arranged between a surface of the electrode assembly and the encapsulation film, and said layer bonds the electrode assembly and the encapsulation film together. The present application facilitates improving safety and battery energy density. Further provided in the present application is an electronic apparatus using said battery.

Description

Battery and electronic device using the same

technical field

The present application relates to the field of batteries, and in particular, to a battery and an electronic device using the battery.

Background technique

With the mature application of consumer electronic products, customers are paying more and more attention to the application risks of the whole machine. For example, the requirements for the anti-drop performance of electronic products are getting higher and higher. As an important part of electronic products, batteries also have requirements for anti-drop performance.

When the battery is dropped along with the electronic product, the electrode assembly accommodated in the battery packaging film is likely to move in the packaging film. When the electrode assembly moves in the encapsulation film, the diaphragm located at the head of the electrode assembly with the tabs and the tail opposite to the head is prone to pleating or shrinking, so that the cathode and anode are in direct contact with each other. This leads to a short circuit of the electrode assembly, which in turn affects the safety of the battery. Therefore, it is usually necessary to stick a wrap around the head and tail of the electrode assembly to fix the diaphragm. However, wrapping will increase the thickness of the battery, resulting in a decrease in the volumetric energy density of the battery.

SUMMARY OF THE INVENTION

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

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

A battery of the present application includes an electrode assembly and an encapsulation film that encapsulates the electrode assembly. The electrode assembly includes 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, and the diaphragm is connected to the first pole piece or the diaphragm. The bonding force between the second pole pieces is ≥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 solution of the present application, the adhesive force between the adhesive layer and the packaging film is 3 N/m to 1000 N/m.

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

As a solution of the present application, the adhesive force between the separator and the first pole piece or the second pole piece is 3 N/m to 30 N/m.

As a solution of the present application, the thickness of the adhesive layer is 1 μm to 20 μm, which is beneficial to reduce the overall thickness of the battery while ensuring the adhesive force, thereby reducing the impact on the energy density of the battery.

As a solution of the present application, the area where the surface of the electrode assembly is bonded to the adhesive layer accounts for 20% to 100% of the area of the surface of the electrode assembly, thereby further ensuring the The stability of the bond between the electrode assembly and the encapsulation film.

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

As a solution of the present application, the adhesive layer is disposed on the surface of the electrode assembly, and the shape of the adhesive layer includes at least one of a block shape, a point shape, or a line shape.

As a solution of the present application, the separator includes a separator substrate and an adhesive layer disposed on the surface of the separator substrate, and a side of the adhesive layer facing away from the separator substrate is connected to the first electrode sheet or the second pole piece is bonded.

As a solution of the present application, the adhesive layer is disposed on two opposite surfaces of the diaphragm substrate, which is beneficial to further reduce the risk of short circuit between the first pole piece and the second pole piece .

The present application also provides an electronic device comprising the above-mentioned battery.

In the present application, a highly viscous separator is arranged in the battery, so that the separator is closely bonded with the first pole piece or the second pole piece. When the battery is subjected to an external force, the separator is not easily pleated or shrunk, and further The short circuit of the electrode assembly can be avoided, so that the battery has high anti-drop performance, the possibility of failure of the battery when the battery is impacted is reduced, and the safety of the battery is improved. At the same time, the adhesive layer bonds the electrode assembly and the encapsulation film together, reducing the movement of the electrode assembly in the encapsulation film or even breaking the encapsulation film when the battery is subjected to external force. Therefore, the drop resistance and safety of the battery are further improved. That is, the high-viscosity separator and the adhesive layer work together to give the battery high drop resistance and safety. On the other hand, since the wrapping of the head and tail of the electrode assembly is eliminated, the thickness of the battery is reduced, which is beneficial to improve the energy density of the battery.

Description of drawings

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

FIG. 2 is a schematic diagram of disassembly of a battery according to an embodiment of the present application.

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

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

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 schematic diagram of an electrode assembly according to an embodiment of the present application.

7 is a schematic 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 main component symbols

电池 Battery	100100
电极组件 Electrode assembly	1010
封装膜 packaging film	3030
胶粘层 adhesive layer	5050
主平面 main plane	101101
弯折面 Bend face	103103
第一极片 first pole piece	1111
第二极片 second pole piece	1313
隔膜 diaphragm	1515
隔膜基材 Diaphragm substrate	151151
粘结层 adhesive layer	153153
电子装置 electronic device	200200

The following specific embodiments will further illustrate the present application in conjunction with the above drawings.

Detailed ways

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. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the application are for the purpose of describing specific embodiments only, and are not intended to limit the application.

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

Referring to FIGS. 1 and 2 , an embodiment of the present application provides a battery 100 , which includes an electrode assembly 10 and an encapsulation film 30 that encapsulates the electrode assembly 10 .

The battery 100 further includes an adhesive layer 50, the adhesive layer 50 is disposed between the surface of the electrode assembly 10 and the encapsulation film 30, and bonds the surface of the electrode assembly 10 and the encapsulation film 30, so as to reduce the electrode assembly when the battery 100 is subjected to external force 10 moves in the packaging film 30 or even breaks the packaging film 30, thereby reducing the possibility of failure of the battery 100 when it is impacted.

Preferably, the adhesive force between the adhesive layer 50 and the packaging 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 encapsulation film 30 are closely bonded, thereby further preventing the electrode assembly 10 from moving in the encapsulation film 30 or even breaking the encapsulation film 30 when the battery 100 is subjected to external force.

In some embodiments, the adhesive layer 50 may be selected from, but not limited to, polyolefins, epoxy resins, silicones, acrylates, or combinations thereof. Preferably, the thickness of the adhesive layer 50 is 1 μm to 20 μm, which is beneficial to reduce the overall thickness of the battery 100 while ensuring the adhesive force, thereby reducing the influence on the energy density of the battery 100 .

The bonding area between the surface of the electrode assembly 10 and the adhesive layer 50 accounts for 20% to 100% of the total area of the surface of the electrode assembly 10 , so as to further ensure the stability of the bonding between the electrode assembly 10 and the packaging film 30 .

Please refer to FIG. 2 , FIG. 3 and FIG. 4 at the same time, on the surface of the electrode assembly 10 , the shape of the adhesive layer 50 may be, but not limited to, the shape of a block, a point, a line, etc., and a combination of the above shapes. at least one.

The electrode assembly 10 is a wound structure, and the surface of the electrode assembly 10 includes two oppositely arranged main planes 101 and two oppositely arranged bending surfaces 103 connecting the two main planes 101 . Preferably, the adhesive layer 50 is disposed on the main plane 101 .

Referring to FIG. 5 , the electrode assembly 10 includes a first pole piece 11 , a second pole piece 13 and a diaphragm 15 . The separator 15 is arranged between the first pole piece 11 and the second pole piece 13 , and the adhesive force between the separator 15 and the first pole piece 11 or the second pole piece 13 is ≥3N/m. In the present application, a highly viscous separator 15 is arranged in the electrode assembly 10, so that the separator 15 is closely bonded with the first pole piece 11 or the second pole piece 13. When the battery 100 is subjected to external force, the separator 15 is not easy to be pleated or contracted. Further, the short circuit of the electrode assembly 10 is avoided, so that the battery 100 can also have high anti-drop performance, and the safety of the battery 100 is further improved. 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 wrapping of the head and the tail of the electrode assembly 10 is eliminated, the increase in the thickness of the battery 100 caused by fixing the diaphragm 15 by wrapping the glue is avoided, which is beneficial to improve the energy density of the battery 100 .

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

In some embodiments, as shown in FIG. 6 , the adhesive layer 153 is only provided on one side of the diaphragm substrate 151 for bonding with the first pole piece 11 or the second pole piece 13 . In some embodiments, please refer 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 opposite surfaces of the diaphragm substrate 151 are respectively bonded to the first One pole piece 11 and the second pole piece 13 are beneficial to further reduce the risk of short circuit between the first pole piece 11 and the second pole piece 13 .

In some embodiments, the material of the membrane substrate 151 may be selected from polyethylene (polyethylene, PE for short), polypropylene (PP), polyethylene terephthalate (PET), etc. at least one of the materials. The membrane substrate 151 may be a single-layer structure or a multi-layer composite structure that is mixed.

In some embodiments, the adhesive layer 153 may include an adhesive in a core-shell structure (not shown), and the adhesive includes a core body and a shell that coats the core body. The core body and the shell are homopolymers or copolymers formed by polymer monomers, and the polymer monomers forming the core body include acrylate monomers, aromatic monovinyl compounds, monocarboxylic acid anhydrides or dicarboxylic acids at least one of 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 shell-forming polymer monomer includes at least one of acrylate-based monomers, aromatic monovinyl compounds, or nitrified vinyl compounds. 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. Nitrilated vinyl compounds include, but are not limited to, acrylonitrile and methacrylonitrile.

In other embodiments, the adhesive layer 153 may be composed of a non-core-shell structure adhesive, and the adhesive includes a homopolymer or a copolymer formed from a polymer monomer, and the polymer monomer includes vinylidene fluoride, hexafluoroethylene At least one of fluoropropylene, acrylic acid, acrylate, butadiene, styrene, acrylonitrile, ethylene, chlorostyrene, fluorostyrene or propylene.

In some embodiments, the adhesive layer 153 may further include an auxiliary adhesive, and the mass ratio of the adhesive to the auxiliary adhesive is (85%-95%):(5%-15%). Secondary binders include ethyl acrylate, butyl acrylate, ethyl methacrylate, styrene, chlorostyrene, fluorostyrene, methylstyrene, acrylic acid, methacrylic acid, maleic acid, acrylonitrile and butanediol At least one of a homopolymer or copolymer of alkene.

Further, the adhesive layer 153 may also contain thickeners and wetting agents. The function of the thickener is to increase the stability of the slurry and prevent the slurry from settling. The role of the wetting agent is to reduce the surface energy of the slurry and prevent coating leakage. The mass of the binder accounts for 88% to 92.5% of the total mass of the bonding layer 153 , the mass of the thickener accounts for 0.5% to 2% of the total mass of the bonding layer 153 , and the mass of the wetting agent accounts for the mass of the bonding layer 153 . 7% to 10% of the total mass. In some embodiments, the thickening agent may be sodium carboxymethyl cellulose (CMC). Wetting agents include dimethylsiloxane, polyethylene oxide, oxyethylene alkyl phenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer, or dioctyl sulfosuccinate at least one of the sodium salts.

In some embodiments, the membrane 15 may also include a ceramic coating (not shown) applied to the membrane substrate 151 . The bonding layer 153 is located on the surface of the ceramic coating and/or the surface of the membrane substrate 151 not coated with the ceramic coating. For example, the ceramic coating is located on one surface of the diaphragm substrate 151, the number of adhesive layers 153 is two, one adhesive layer 153 is located on the surface of the ceramic coating, and the other adhesive layer 153 is located on the diaphragm substrate 151 without the Ceramic coated surface. Among them, the ceramic coating is used to improve the heat resistance and puncture resistance of the diaphragm 15 . Nanoscale inorganic particles are arranged in the ceramic coating, and the inorganic ceramic particles can be selected from but not limited to hydrated alumina (boehmite), alumina, silica, titania, cerium oxide, calcium carbonate, calcium oxide, zinc oxide , at least one of magnesium oxide, cerium titanate, calcium titanate, barium titanate, barium sulfate, lithium phosphate or lithium titanium phosphate.

In other embodiments, the membrane 15 may also not contain a ceramic coating. At this time, the bonding layer 153 may further include nano-scale inorganic ceramic particles. By adding inorganic ceramic particles to the adhesive layer 153, the heat resistance and puncture resistance of the separator 15 can also be improved.

Referring to FIG. 8 , the above-mentioned battery 100 is applied to the electronic device 200 . The electronic device 200 may be, but is not limited to, a cell phone, a toy, a notebook computer, an e-reader, and the like.

The present application will be specifically described below through comparative examples and examples. It can 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 selected according to actual needs.

Comparative Example 1

Preparation of cathode electrode sheet: 10 μm aluminum foil was selected as cathode current collector, and lithium cobalt oxide, conductive carbon black and polyvinylidene fluoride were dissolved in N-methylpyrrolidone (NMP) in a mass ratio of 97:1.4:1.6 In a solvent, a cathode active slurry is formed, the cathode active slurry is coated on the surface of the cathode current collector, dried and cold pressed to obtain a cathode electrode sheet.

Preparation of anode sheet: 6 μm copper foil was selected as anode current collector, and graphite, conductive carbon black, CMC and styrene-butadiene rubber (SBR) were dissolved in deionized water in a mass ratio of 96.5:1.0:1.0:1.5. Under the action of a vacuum mixer, the system is stirred until the system is uniform to obtain an anode active slurry, and the anode active slurry is coated on the surface of the anode current collector, dried and cold pressed to obtain an anode electrode sheet.

Preparation of diaphragm: 5 μm polyethylene (PE) was selected as the diaphragm substrate, and a ceramic coating with a thickness of 2 μm was coated on one side of the diaphragm substrate, and the ceramic coating included boehmite with a particle size D50 of 0.8 μm to 1 μm ; Take 2 parts of acrylic copolymer and add it to 100 parts of water and stir evenly, then add 35 parts of polyvinylidene fluoride (PVDF), then add 0.5 parts of thickener sodium carboxymethyl cellulose (CMC), and then the slurry is uniform It is coated on the separator substrate and ceramic coating, and then dried to obtain the separator.

Preparation of electrode assembly: the above-mentioned cathode electrode sheet, the above-mentioned separator and the above-mentioned anode electrode sheet are stacked in sequence and then wound to form a wound electrode assembly, and a double-sided hot melt with a length of 70 mm, a width of 20 mm and a thickness of 48 μm is passed through. The tape (as the adhesive layer that is bonded to the packaging film during subsequent packaging) ends, and the adhesive force between the hot-melt tape and the packaging film is 158.5N/m. Then, a single-sided hot-melt adhesive with a length of 24mm and a thickness of 48μm is used to wrap one piece of glue on the head of the electrode assembly with the tabs, and two lines of glue for the bottom of the electrode assembly opposite to the head. . Among them, the adhesive force between the separator and the cathode electrode sheet is 1.1 N/m, and the adhesive force between the separator and the anode electrode sheet is 0.4 N/m.

Preparation of battery: The above electrode assembly was encapsulated, dried, injected with liquid through the encapsulation film, and processed for 40 minutes under the pressure of 80 degrees Celsius and 1030kg/2ea, and then degassed, sealed and folded to make the battery. Wherein, the adhesive layer bonds the encapsulation film and the electrode assembly.

Example 1

Preparation of cathode pole piece: the difference from Comparative Example 1 is that polyolefin hot-melt adhesive was coated on the blank area of the tail of the pole piece prepared in Comparative Example 1 and dried to form an adhesive layer, wherein the adhesive layer was The thickness of the layers is 1 μm.

Preparation of anode electrode sheet: the same as that of Comparative Example 1.

Preparation of diaphragm: choose PE with a thickness of 5 μm as the diaphragm substrate, and coat a ceramic coating with a thickness of 2 μm on one side of the diaphragm substrate. The ceramic coating includes boehmite with a particle size D50 of 0.8 μm to 1 μm; 91wt% of the binder is added into the mixer, the polymerized monomers of the binder include 0.8 parts of styrene, 0.1 part of isobutyl acrylate and 0.1 part of acrylonitrile, and then 0.5wt% of the thickener carboxymethyl cellulose is added Sodium (CMC), then continue to add 8.5wt% of the wetting agent dimethylsiloxane, and finally add deionized water to adjust the viscosity of the slurry, and then evenly coat the slurry on the diaphragm substrate and ceramic coating, respectively An adhesive layer (8.3 μm in thickness) was formed thereon, and drying was completed by passing through an oven, thereby producing a separator.

Preparation of electrode assembly: the cathode electrode sheet, the separator and the anode electrode sheet are stacked in sequence and then wound to form a coiled electrode assembly, which is finished with a green glue with a thickness of 10 μm. Wherein, after winding, the cathode electrode sheet is provided with a blank area of the adhesive layer as the entire surface of the electrode assembly, and the area where the surface of the electrode assembly and the adhesive layer are bonded accounts for 50% of the total surface area of the electrode assembly. The adhesive force between the separator and the cathode electrode piece is 3 N/m, and the adhesive force between the separator and the anode electrode piece is 3 N/m.

Preparation of battery: the same as that of Comparative Example 1.

Example 2

Preparation of cathode electrode sheet: The difference from Example 1 is that the thickness of the adhesive layer is 6 μm.

Preparation of anode electrode sheet: the same as in Example 1.

Preparation of separator: The difference from Example 1 is that the polymerized monomers of the binder include 0.7 parts of styrene, 0.2 parts of isobutyl acrylate and 0.1 parts of acrylonitrile.

Preparation of electrode assembly: The difference from Example 1 is that the area where the surface of the electrode assembly is bonded with the adhesive layer accounts for 20% of the total area of the surface of the electrode assembly. The adhesive force between the separator and the cathode electrode sheet was 9.1 N/m, and the adhesive force between the separator and the anode electrode sheet was 10.2 N/m.

Preparation of battery: the same as in Example 1.

Example 3

Preparation of cathode electrode sheet: The difference from Example 1 is that the thickness of the adhesive layer is 8 μm.

Preparation of anode electrode sheet: the same as in Example 1.

Preparation of separator: The difference from Example 1 is that the polymerized monomers of the binder include 0.6 parts of styrene, 0.3 parts of isobutyl acrylate and 0.1 parts of acrylonitrile.

Preparation of electrode assembly: The difference from Example 1 is that the area where the surface of the electrode assembly is bonded with the adhesive layer accounts for 40% of the total area of the surface of the electrode assembly. The adhesive force between the separator and the cathode electrode sheet was 9.8 N/m, and the adhesive force between the separator and the anode electrode sheet was 10.6 N/m.

Preparation of battery: the same as in Example 1.

Example 4

Preparation of cathode electrode sheet: The difference from Example 1 is that the thickness of the adhesive layer is 10 μm.

Preparation of anode electrode sheet: the same as in Example 1.

Preparation of separator: 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 is that the area where the surface of the electrode assembly is bonded with the adhesive layer accounts for 80% of the total area of the surface of the electrode assembly. The adhesive force between the separator and the cathode electrode sheet was 8.8 N/m, and the adhesive force between the separator and the anode electrode sheet was 9.8 N/m.

Preparation of battery: the same as in Example 1.

Example 5

Preparation of cathode electrode sheet: The difference from Example 1 is that the thickness of the adhesive layer is 15 μm.

Preparation of anode electrode sheet: the same as in Example 1.

Preparation of separator: The difference from Example 1 is that the polymerized monomers of the binder include 0.8 part of propylene, 0.1 part of acrylonitrile and 0.1 part of acrylic acid.

Preparation of electrode assembly: The difference from Example 1 is that the area where the surface of the electrode assembly is bonded with the adhesive layer accounts for 80% of the total area of the surface of the electrode assembly. The adhesive force between the separator and the cathode electrode sheet was 9.5 N/m, and the adhesive force between the separator and the anode electrode sheet was 10.5 N/m.

Preparation of battery: the same as in Example 1.

Example 6

Preparation of cathode electrode sheet: The difference from Example 1 is that the thickness of the adhesive layer is 20 μm.

Preparation of anode electrode sheet: the same as in Example 1.

Preparation of separator: the same as in Example 1.

Preparation of electrode assembly: The difference from Example 1 is that the area where the surface of the electrode assembly is bonded with the adhesive layer accounts for 80% of the total area of the surface of the electrode assembly. The adhesive force between the separator and the cathode electrode piece is 3 N/m, and the adhesive force between the separator and the anode electrode piece is 3 N/m.

Preparation of battery: the same as in Example 1.

Comparative Example 4

Preparation of cathode electrode pieces: the same as in Example 6.

Preparation of anode electrode sheet: the same as in Example 6.

Preparation of separator: the same as in Comparative Example 1.

Preparation of electrode assembly: the same as in Example 6, except that the adhesive force between the separator and the cathode electrode sheet is 1.1 N/m, and the adhesive force between the separator and the anode electrode sheet is 0.4 N/m.

Preparation of battery: the 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

Thickness measurements were performed on the batteries prepared in Comparative Examples 1-2 and Examples 1-6. Then, the batteries prepared in Comparative Examples 1-2 and Examples 1-6 were subjected to a drop test, and the corresponding drop results were recorded in Table 2 below. Take 10 batteries of each group of comparative examples or examples for testing. The specific method of the drop test is: first adjust the voltage of the battery to 100% SOC, and measure the voltage and internal voltage of the battery before the drop after charging and standing for 2 hours. Put the battery, stop bar and silicone pad into the fixture compartment (electrode assembly - stop bar - silicone pad) in turn, and put a 1mm silicone pad on the battery surface, press with a 5kg pressure block for 12 hours, and then install the upper cover of the fixture compartment board; use automatic equipment drop equipment to drop the fixture compartment with battery from the position of 1.5 meters in turn in the manner of the head, tail, upper right corner, lower right corner, upper left corner, and lower left corner of the fixture compartment from the position of 1.5 meters, a total of 3 The round is 18 times. The voltage of the battery is measured after each round of falling. When the battery catches fire, heats up, leaks, and the voltage drop is ≥50mV, it stops falling, otherwise it continues to fall to complete 3 rounds. After 3 rounds of falling, take out the battery and let it stand at room temperature for 24 hours before measuring the voltage and internal resistance of the battery. The measurement results are reported in Table 2 below.

Table 2

It can be seen from the data in the table that, compared with Comparative Example 1, the batteries of Examples 1-6 of the present application do not have the glue around the head and bottom of the electrode assembly, and at the same time are provided with a high-viscosity separator, which is conducive to reducing the overall thickness of the battery. On the premise, it maintains a high battery anti-drop performance.

Comparing Comparative Example 2 and Example 6, both Comparative Example 2 and Example 6 were provided with polyolefin hot-melt adhesive on the surface of the electrode assembly. However, the anti-drop performance of the battery in Example 6 was greatly improved compared with Comparative Example 2, indicating that the embodiment 6 The setting of the high-viscosity separator is the main reason why the battery can maintain high anti-drop performance.

In addition, for those of ordinary skill in the art, various other corresponding changes and deformations can be made according to the technical concept of the present application, and all these changes and deformations should belong to the protection scope of the present application.

Claims

A battery, comprising an electrode assembly and a packaging film encapsulating the electrode assembly, characterized in that the electrode assembly includes a first pole piece, a second pole piece and a separator, and the separator is arranged on the first pole piece and the separator. Between the second pole pieces, the adhesive force between the separator and the first pole piece or the second pole piece is greater than or equal to 3N/m, and the battery further includes an adhesive layer. A layer is disposed between the surface of the electrode assembly and the encapsulation film and bonds the electrode assembly and the encapsulation film together.
The battery of claim 1, wherein the adhesive force between the adhesive layer and the packaging film is 3 N/m to 1000 N/m.
The battery of claim 1, wherein the adhesive force between the adhesive layer and the surface of the electrode assembly is 3 N/m to 1000 N/m.
The battery of claim 1, wherein the adhesive force between the separator and the first pole piece or the second pole piece is 3 N/m to 30 N/m.
The battery of claim 1, wherein the thickness of the adhesive layer is 1 μm to 20 μm.
The battery of claim 1, wherein an area where the surface of the electrode assembly is bonded to the adhesive layer accounts for 20% to 100% of the total area of the surface of the electrode assembly.
The battery of claim 1, wherein the adhesive layer comprises at least one of polyolefin, epoxy resin, silicone or acrylate.
The battery according to claim 1, wherein the adhesive layer is disposed 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 line shape .
The battery of claim 1, wherein the separator comprises a porous substrate and an adhesive layer disposed on the surface of the porous substrate, the adhesive layer facing away from the porous substrate and The first pole piece or the second pole piece is bonded.
The battery of claim 9, wherein the adhesive layer is disposed on two opposite surfaces of the porous substrate.
An electronic device, characterized in that, the electronic device comprises the battery according to any one of claims 1-10.