Battery and preparation method therefor, and electric device

Abstract

The present disclosure provides a battery and a preparation method therefor, and an electric device. The battery comprises: a separator, which comprises a base film and an adhesive arranged on at least one side of the base film. The adhesive comprises: a core, which comprises an acrylate copolymer and a coating material at least partially covering the surface of the core, wherein the coating material comprises at least one of a water-soluble silicate and an anti-caking agent, and the mass ratio of the core to the coating material is 100:(0.1-20).

Description

Battery and preparation method thereof, and power utilization device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of batteries, and in particular, to a battery and a preparation method thereof, and a power utilization device. BACKGROUND

[0002] In recent years, batteries are widely used in energy storage power systems such as hydroelectric, thermal, wind and solar power stations, and in many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. As a non-active material in the battery, the binder is used to bond each component in the battery and adjacent battery parts together. Although the cost and amount of the binder in the battery are small, it can effectively improve the performance of the battery. For example, the binder on the separator can effectively improve the bonding strength between the separator and the pole piece. Good bonding strength helps the separator and the pole piece to adhere to each other and support each other, thereby reducing the internal resistance of the battery. However, there are still problems such as insufficient bonding force in the current battery, which needs to be further improved.

[0003] It should be noted that the above statements are only used to provide background technical information related to the present application, and do not necessarily constitute the prior art.

[0004] SUMMARY

[0005] In a first aspect of the present application, a battery is provided, comprising: a separator, the separator comprising a base film and a binder located on at least one side of the base film, the binder comprising: an inner core, the inner core comprising an acrylate copolymer; a coating material, the coating material at least partially covering the surface of the inner core, the coating material comprising at least one of a water-soluble silicate and an anti-blocking agent, and the mass ratio of the inner core to the coating material is 100:(0.1-20). Thus, the binder has good anti-swelling and processing performance, the separator is not prone to self-bonding during winding, and the bonding between the separator and the pole piece after rolling is relatively firm, and the cycle performance of the battery is good.

[0006] In some embodiments, the mass ratio of the inner core to the coating material is 100:(2-15). Thus, both the poor self-bonding of the separator and the good bonding performance of the binder after rolling can be alleviated.

[0007] In some embodiments, the water-soluble silicate comprises at least one of sodium silicate, potassium silicate, lithium silicate, calcium silicate, magnesium silicate, sodium aluminum silicate, and a water-soluble organic polymer compound. The water-soluble organic polymer comprises at least one of polyacrylic acid, polyacrylamide, and polyvinyl alcohol. Thus, it helps to improve the poor self-bonding of the separator.

[0008] In some embodiments, the anti-blocking agent comprises at least one of potassium ferrocyanide, tricalcium phosphate, silicon dioxide, ferric tartrate, ferric ammonium citrate, and microcrystalline cellulose. Thus, it is helpful to improve the self-bonding of the separator film.

[0009] In some embodiments, the monomers of the acrylic copolymer comprise a first monomer, a second monomer, and a third monomer, the first monomer comprises at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, trimethylolpropane triacrylate, acrylonitrile, methacrylonitrile, ethyl acrylonitrile, vinyl acetate, styrene, butadiene, and isoprene; the second monomer comprises at least one of ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isooctyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate; and the third monomer comprises at least one of acrylic acid, methacrylic acid, butenyl acid, heptenyl acid, itaconic acid, maleic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylamide, and N-methylol acrylamide. Thus, the binder has better bonding performance.

[0010] In some embodiments, the acrylic copolymer has a mass ratio of the first monomer, the second monomer, and the third monomer of (0.1-0.4):1:(0.1-0.2). Thus, the acrylic copolymer has higher toughness, better infiltration between the pole piece after rolling, can fully exert the intermolecular force, and improve the bonding performance of the binder.

[0011] In some embodiments, the binder has a Dv50 particle size of 5-25 μm. Thus, it can reduce the blocking of the binder to the pores of the base film, and make the coating thickness formed by the binder moderate.

[0012] In the second aspect of the present application, a method for preparing the aforementioned battery is provided, comprising: mixing an acrylic copolymer emulsion and a solution of a coating material to obtain a mixed slurry, wherein the coating material comprises at least one of a water-soluble silicate and an anti-blocking agent; performing spray drying treatment on the mixed slurry to obtain a binder; and disposing the binder on at least one side of a base film to obtain a separator film, thereby obtaining the battery. Thus, the aforementioned battery can be prepared by a simple method.

[0013] In some embodiments, the mass fraction of the coating material in the solution of the coating material is 10%-30%. Thus, it is helpful to obtain a binder with better performance.

[0014] In some embodiments, the separator film is arranged between the positive electrode tab and the negative electrode tab, and a cold-pressing process is performed to obtain the battery. In this way, the separator film can better bond the adjacent electrode tabs.

[0015] In a third aspect of the present application, a power consuming device is provided, which comprises the battery as described above. In this way, the power consuming device has all the features and advantages of the battery as described above, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0017] FIG. 1 is a scanning electron microscope image of a polymer according to an embodiment of the present application;

[0018] FIG. 2 is a schematic view of a battery cell according to an embodiment of the present application;

[0019] FIG. 3 is an exploded view of the battery cell shown in FIG. 2 according to an embodiment of the present application;

[0020] FIG. 4 is a schematic view of a battery module according to an embodiment of the present application;

[0021] FIG. 5 is a schematic view of a battery pack according to an embodiment of the present application;

[0022] FIG. 6 is an exploded view of the battery pack shown in FIG. 5 according to an embodiment of the present application;

[0023] FIG. 7 is a schematic view of a power consuming device using the battery as a power source according to an embodiment of the present application.

[0024] BRIEF DESCRIPTION OF REFERENCE NUMERALS: 1 battery pack; 2 upper case; 3 lower case; 4 battery module; 5 battery cell; 11 negative current collector; 12 negative active material layer; 21 positive current collector; 22 positive active material layer; 31 base film; 32 polymer; 51 housing; 52 electrode assembly; 53 top cover assembly; 110 primary binder particles; 120 secondary binder particles; 200 functional coating. DETAILED DESCRIPTION

[0025] Embodiments of the present application are described in detail below with reference to the attached drawings, which are provided as examples and thus do not limit the subject matter of the claims. For example, the detailed description is provided with reference to the accompanying drawings, but the detailed description is not limited to the examples provided in the drawings. In the drawings, similar reference numerals are used to refer to similar elements throughout the several views. The size of elements in the drawings can be exaggerated for the sake of clarity. Also, like reference numerals are used to denote like elements throughout the several views. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the subject matter of the claims and are not intended to limit the subject matter of the claims.

[0026] Unless otherwise defined, 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 in the specification is for describing particular embodiments only and is not intended to be limiting of the application; and any parameters recited are only approximations, unless otherwise specified. Unless otherwise specified, any parameters recited are approximations.

[0027] As used in the description of the application and the appended claims, the terms "including" and "having", along with their derivatives, are meant to be construed open-ended terms, i.e., meaning including, but not limited to.

[0028] In describing and claiming the application, all numbers are to be understood as approximations, unless otherwise specified. Each numerical value should be construed in light of the statement "plus or minus 10% or within a range of values that one of ordinary skill in the art would accept for the particular parameter.

[0029] The ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other, unless specifically indicated otherwise. It is specifically intended that the ranges include both values and sub-ranges encompassed therein. For example, a range of "about 0.1 to about 10" is specifically intended to include "from 0.1 to 10," "from 0.1 to 2.1," "from 1.1 to 10," "from 2.1 to about 10," etc. Also, use of the "term "about" means that a value described is approximately that value and thus can vary from the stated value by a reasonable amount, or, in the case of a range, approximately between the values that define the range. For example, "about 10" means that the value of 10 can vary between 8 and 12, or approximately between 8 and 12. In addition, when a parameter is stated as being an integer, it is understood that the parameter can be any integer value, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0030] All embodiments and optional embodiments of the application can be combined with each other, unless otherwise specified, to form new technical solutions.

[0031] All technical features and optional technical features of the application can be combined with each other, unless otherwise specified, to form new technical solutions.

[0032] Generally, the battery includes a positive electrode sheet, a negative electrode sheet and a separator. A binder needs to be provided between the separator and the electrode sheet in order to tightly bond the two parts together. The positive electrode sheet, the negative electrode sheet and the separator bonded together are in close contact with each other and support each other, forming a structure with a certain thickness, so that the battery has a certain hardness. At the same time, the negative electrode sheet will swell and shrink in volume during the charging and discharging process of the battery. When the bonding force between the separator and the electrode sheet is weak, gaps will be formed between the positive electrode sheet, the negative electrode sheet and the separator due to swelling and shrinking, resulting in the positive electrode sheet, the negative electrode sheet and the separator not being in close contact with each other and supporting each other. Ultimately, the battery becomes loose, the hardness decreases, and the internal resistance increases significantly, thereby significantly reducing the cycle performance of the battery.

[0033] By providing a binder on the surface of the base film of the separator, the bonding performance of the separator can be effectively improved, and the bonding effect between the separator and the electrode sheet can be improved, so that the separator has better bonding performance. Taking polyvinylidene fluoride binder as an example, although the bonding performance of polyvinylidene fluoride binder is better, the cost of polyvinylidene fluoride is high, and a hot pressing process is needed to tightly bond the separator and the electrode sheet. The temperature control and pressure control in the hot pressing process are relatively complex, and the energy consumption is high. In order to realize the speed reduction of the battery production line, the hot pressing process is gradually replaced by the cold pressing process to realize effective bonding between the electrode sheet and the separator by means of the original battery process. Specifically, the cold pressing process refers to a process of shaping the wound battery cell (i.e. the electrode assembly made by the winding process) at a lower ambient temperature than the hot pressing process, so that the elasticity of the battery cell is reduced, and the consistency of the qualified rate of the battery cell and the thickness of the finished battery cell is improved. Because the ambient temperature of the cold pressing process is low, a binder with a lower glass transition temperature needs to be used to achieve effective bonding between the electrode sheet and the separator. Acrylate copolymer can have a lower glass transition temperature by adjusting the type and ratio of monomers, and then can be used as a binder for cold pressing process to achieve effective bonding between the electrode sheet and the separator.

[0034] In order to facilitate storage and storage, the dried isolation film needs to be wound after being coated with an acrylate copolymer on the base film to form an adhesive layer and obtained through a drying process. Due to the low glass transition temperature of the acrylate copolymer, it has good adhesion at room temperature. In the winding process of the isolation film, the adhesive layers on the surface of the isolation film will be bonded to each other, and the isolation film will be self-bonded. When the isolation film includes a base film and a functional coating (such as a ceramic coating) sequentially stacked on both sides of the base film, and an adhesive layer (i.e. a layer structure formed by the adhesive) formed by a spraying process, after the isolation film is wound, the polymer in the adhesive layer will be tightly bonded with the adjacent functional coating. When the adhesion of the adhesive layer is too large, during the unwinding of the isolation film, the adhesive layer will stick the adjacent functional coating from the surface of the base film, resulting in a gap between the functional coating and the base film, and the isolation film cannot be used normally. When the isolation film includes a base film and an adhesive layer on both sides of the base film, after the isolation film is wound, the adjacent adhesive layers will be tightly bonded, so that the interaction between the adjacent base films is large. During the unwinding of the isolation film, the adhesive layer will affect the tension stability of the unwinding of the isolation film, affect the consistency of the cell winding, and then affect the consistency between the cells.

[0035] In the present application, when the mass ratio of the acrylate copolymer to the coating material is 100:(0.1-20), the coating material forms a complete or partial coating layer on the surface of the acrylate copolymer. The coating layer acts as a physical isolation layer to effectively block the direct contact and adhesion between the acrylate copolymer particles, thereby reducing the adhesion of the acrylate copolymer that has not been subjected to rolling treatment. This helps to reduce the adhesion of the acrylate copolymer itself during the winding and unwinding of the isolation film, and further reduces the adhesion of the isolation film itself.

[0036] Further, when the isolation film is cold-pressed after being wound with the pole piece, the acrylate copolymer will deform under pressure, break through the constraints of the coating layer, exhibit good adhesion properties, effectively bond with the pole piece, and at the same time improve the intermolecular forces of the acrylate copolymer itself, achieving tight adhesion between the isolation film and the pole piece. In addition, due to the good chemical resistance and anti-swelling ability of the coating material, the adhesive has good chemical stability and less swelling in the electrolyte, which helps to improve the dimensional stability of the adhesive and the structural stability of the isolation film

[0037] Adhesive refers to a material with adhesive properties used to bond different substances together.

[0038] Copolymer, a polymerization reaction involving two or more monomers, is called copolymerization. The polymer formed contains two or more monomer units, and such polymer is called copolymer, also known as copolymer.

[0039] In some embodiments, the acrylate copolymer emulsion can be prepared by emulsion polymerization, the acrylate copolymer emulsion is mixed with a solution of the coating material to obtain a mixed slurry, and the mixed slurry is subjected to spray drying. After spray drying, the coating material tends to migrate to the surface of the acrylate copolymer, forming a coating layer structure. The coating layer structure not only prevents direct contact between the acrylate copolymer powder particles, reduces the friction between the powder particles, and increases the flowability of the powder, but also is insoluble in water, so that the acrylate copolymer is not easily coagulated due to moisture in the air or other factors, and the loose state of the powder is maintained, greatly alleviating the self-sticking of the acrylate copolymer.

[0040] Specifically, the solution of the coating material is mixed and subjected to spray drying. During spray drying, the droplets containing the coating material and the acrylate copolymer emulsion are sprayed in the form of droplets, and then meet and mix in the air. During the mixing process, the coating material forms a complete coating or a partially coated physical isolation layer (i.e., a coating layer formed by the coating material) on the surface of the acrylate copolymer particles under the action of surface tension. The physical isolation layer tends to grow on the surface of the acrylate copolymer emulsion particles, which helps to improve the processing performance of the acrylate copolymer emulsion, reduce the caking of the acrylate copolymer particles, and improve the yield of spray drying.

[0041] In a first aspect of the present application, a battery is provided, comprising: a separator film, the separator film comprising a base film and a binder located on at least one side of the base film, the binder comprising: an inner core, the inner core comprising an acrylate copolymer; a coating material, the coating material at least partially covering the surface of the inner core, the coating material comprising at least one of a water-soluble silicate and an anti-caking agent, and the mass ratio of the inner core to the coating material being 100:(0.1-20). When the mass ratio of the acrylate copolymer to the coating material is 100:(0.1-20), the coating layer formed by the coating material as a physical isolation layer can effectively prevent direct contact and sticking between the acrylate copolymer particles, which helps to reduce the self-sticking of the separator film during the winding and unwinding of the separator film. Further, after the separator film and the pole piece are wound and subjected to cold pressing, the binder can exhibit good sticking properties, realizing the close sticking between the separator film and the pole piece, and the battery has good cycle performance. In addition, the good anti-swelling ability of the coating material also helps to improve the anti-swelling property of the binder.

[0042] In some embodiments, the mass ratio of the inner core to the coating material is 100:(2-15). In this way, the self-sticking of the separator film can be alleviated, and the binder can have good sticking properties after rolling.

[0043] As an example, the mass ratio of the core to the coating material can be 100:0.1, 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15, 100:16, 100:17, 100:18, 100:19, or 100:20.

[0044] In some embodiments, the core and the coating material on the surface of the core collectively form a binder primary particle 110, a plurality of the binder primary particles 110 are agglomerated to form a binder secondary particle 120, for example, see FIG. 1 (the binder is shown on the side of the functional coating 200 away from the base film), the binder secondary particle 120 is formed by agglomeration of a plurality of binder primary particles 110 with a particle size of 100-200 nm, at this time, the coating material is on the outside and the inside of the binder, and the coating material on the outside of the binder is more.

[0045] In some embodiments, the water-soluble silicate includes at least one of sodium silicate, potassium silicate, lithium silicate, calcium silicate, magnesium silicate, sodium aluminum silicate, and a water-soluble organic polymer compound, thereby helping to improve the poor self-bonding of the release film.

[0046] The water-soluble silicate and the water-soluble organic polymer compound refer to a substance used in combination with the water-soluble silicate and the water-soluble organic polymer, wherein the water-soluble organic polymer includes at least one of polyacrylic acid, polyacrylamide, and polyvinyl alcohol.

[0047] The water-soluble silicate can be uniformly dispersed in water to form a solution of the water-soluble silicate, and the solution of the water-soluble silicate and the emulsion of the acrylate copolymer are mixed to obtain a mixed slurry. In the process of spray drying the mixed slurry, the solvent in the solution of the water-soluble silicate volatilizes, and the water-soluble silicate solidifies and adheres to the surface of the acrylate copolymer latex, and forms a protective layer, thereby effectively blocking the direct contact and adhesion between the acrylate copolymer particles, improving the processing performance of the acrylate copolymer, and increasing the yield of the powder.

[0048] As an example, the water-soluble organic polymer can promote the solidification of the water-soluble silicate.

[0049] In some embodiments, the anti-blocking agent includes at least one of potassium ferrocyanide, tricalcium phosphate, silicon dioxide, iron tartrate, ferric ammonium citrate, and microcrystalline cellulose, thereby helping to improve the poor self-bonding of the release film.

[0050] The anti-caking agent can be uniformly dispersed in water to form a solution of the anti-caking agent. The solution of the anti-caking agent can be mixed with the emulsion of the acrylate copolymer to obtain a mixed slurry. During the spray drying of the mixed slurry, the anti-caking agent forms a protective layer on the surface of the acrylate copolymer latex, which has anti-caking properties. Specifically, the anti-caking agent can reduce the friction between the acrylate copolymer particles and the formation of liquid bridges. The anti-caking agent itself has strong hygroscopicity and can compete with the acrylate copolymer for moisture, reducing the caking tendency of the acrylate copolymer due to hygroscopicity. The anti-caking agent can also eliminate the static charge and molecular forces on the surface of the acrylate copolymer, reducing the adverse forces between the acrylate copolymer molecules and improving the flowability. Thus, the anti-caking agent can effectively improve the processability of the acrylate copolymer and increase the yield of the powder.

[0051] In some embodiments, the monomers of the acrylate copolymer include a first monomer, a second monomer, and a third monomer.

[0052] In some embodiments, the first monomer includes at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, trimethylolpropane triacrylate, acrylonitrile, methacrylonitrile, ethyl acrylonitrile, vinyl acetate, styrene, butadiene, and isoprene. The first monomer is a hard monomer, which helps to increase the glass transition temperature (Tg) of the acrylate copolymer. The polymer segment formed by the first monomer is relatively hard and not easy to deform, and the addition of the first monomer can improve the hardness, chemical resistance, and thermal stability of the acrylate copolymer.

[0053] In some embodiments, the second monomer includes at least one of ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, isooctyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate.

[0054] The second monomer is a soft monomer, which helps to reduce the glass transition temperature of the acrylate copolymer. The polymer segment formed by the second monomer is relatively soft and elastic, and the addition of the second monomer can improve the flexibility, ductility, and processability at low temperatures of the acrylate copolymer, which helps to make the adhesive more suitable for cold pressing processes.

[0055] The third monomer includes at least one of acrylic acid, methacrylic acid, butenoic acid, heptoenoic acid, itaconic acid, maleic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylamide, and N-hydroxymethyl acrylamide. Thus, the adhesive has better adhesive properties.

[0056] The third monomer is a functional monomer, and the addition of the third monomer helps to improve the properties of the acrylate copolymer. For example, the unsaturated ester group in the third monomer can form the backbone of the molecular chain segment of the acrylate copolymer, so that the acrylate copolymer has excellent stability and better adhesion, and helps to improve the anti-swelling property of the acrylate copolymer; the unsaturated double bond in the third monomer is beneficial to the polymerization of the monomer; the carboxyl group in the third monomer can be combined with the functional groups on the base film to improve the adhesion of the acrylate copolymer to the base film, and can also increase the crosslinking active sites of the acrylate copolymer, thereby improving the anti-creep property and cohesive strength of the acrylate copolymer; the unsaturated amide group in the third monomer can play a role in adjusting the molecular weight, and can also improve the adhesion and anti-swelling property of the acrylate copolymer.

[0057] In some embodiments, the mass ratio of the first monomer, the second monomer, and the third monomer in the acrylate copolymer is (0.1-0.4):1:(0.1-0.2). Thus, the acrylate copolymer has high toughness, good infiltration between the polar pieces after cold pressing, and can fully exert the intermolecular force to improve the adhesive properties of the adhesive.

[0058] The acrylate copolymer has high toughness, and can better infiltrate and exert intermolecular force after cold pressing, so that it has good adhesive force. It can effectively alleviate the soft electric core, opening and other defects caused by insufficient adhesive force.

[0059] By optimizing the types and amounts of monomers of the acrylate copolymer, an acrylate copolymer with excellent performance can be obtained. The acrylate copolymer has high toughness, can better infiltrate and exert intermolecular force after cold pressing, and has good adhesive force. The coating material added in the acrylate copolymer can reduce the aggregation and clumping of acrylate copolymer particles or powders, and keep them in a loose or free-flowing state.

[0060] In some embodiments, the Dv50 particle size of the adhesive is 5-25 μm. Thus, the adhesive can reduce the blockage of the base film channels, and the coating thickness formed by the adhesive is moderate.

[0061] As an example, the Dv50 particle size of the binder can be 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 11 pm, 12 pm, 13 pm, 14 pm, 15 pm, 16 pm, 17 pm, 18 pm, 19 pm, 20 pm, 21 pm, 22 pm, 23 pm, 24 pm, or 25 pm.

[0062] The aforementioned Dv50 particle size refers to the particle size corresponding to the cumulative volume distribution percentage of 50%. The "Dv50 particle size" in the present application has the meaning known in the art and can be measured by using instruments and methods known in the art. As an example, the particle size of the acrylate copolymer can be measured by using a laser diffraction particle size analysis method. Specifically, the particle size of the acrylate copolymer can be measured by using a laser particle size analyzer (e.g., Malvern-Master-Size-3000) according to the standard GB / T 19077-2016.

[0063] As an example, the mixed slurry obtained by mixing the acrylate copolymer emulsion and the solution of the coating material can be subjected to spray drying to obtain the binder, and the binder can be directly tested to obtain the Dv50 particle size.

[0064] As an example, the acrylate copolymer in the acrylate copolymer emulsion can maintain its original particle size during spray drying, the coating material can be fully dissolved in water (except for silicon dioxide), and uniformly distributed on the surface of the acrylate copolymer after spray drying, and has little contribution to the particle size. Therefore, the acrylate copolymer emulsion can be directly subjected to spray drying to obtain acrylate copolymer particles, the particle size of the acrylate copolymer particles can be tested, and the particle size of the acrylate copolymer particles can be regarded as the Dv50 particle size of the binder.

[0065] In some embodiments, the separation film can include a base film, a functional coating layer (e.g., a ceramic coating layer), and a bonding layer (i.e., a coating layer of the binder) which are sequentially stacked.

[0066] As an example, the bonding layer can be formed by using a spraying method, and the coverage of the bonding layer on the functional coating layer can be about 15%.

[0067] In some embodiments, the base film of the separation film can include at least one of polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and non-woven fabric.

[0068] By using the above-mentioned material for the base film, the adhesion of the binder on the base film can be effectively improved, and thus the structural stability of the separation film can be improved.

[0069] During the charging and discharging of the battery, active ions are inserted and de-inserted between the positive electrode sheet and the negative electrode sheet. The electrolyte serves to conduct the active ions between the positive electrode sheet and the negative electrode sheet. The separator is disposed between the positive electrode sheet and the negative electrode sheet, and mainly serves to prevent the positive electrode and the negative electrode of the battery from short-circuiting, while allowing ions to pass through.

[0070] [Positive electrode sheet]

[0071] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on at least one side surface of the positive electrode current collector, the positive electrode active material layer including a positive electrode active material.

[0072] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode active material layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0073] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be employed. The composite current collector can include a polymer material base layer and a metal layer formed on at least one side surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material base material (e.g., a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0074] In some embodiments, when the battery is a lithium ion battery, the positive electrode active material can employ a positive electrode active material for a lithium ion battery known in the art.

[0075] As an example, the positive electrode active material can include at least one of a lithium-containing phosphate having an olivine structure, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material for a battery can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, the lithium transition metal oxide can include lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM523 LiNi 0.5 Co 0.25 Mn 0.25 O2(also can be referred to as NCM 211 LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM 622 LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM 811 LiNi 0.8 Co 0.15 Al 0.05 O2) and modified compounds thereof. Examples of the olivine-structured lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4(also can be referred to as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon. The modified compounds of each of the above materials can be a doping modification and / or a surface coating modification of the material.

[0076] The battery will be accompanied by Li deintercalation and consumption during charging and discharging, and the molar content of Li is different when the battery is discharged to different states. In the enumeration of the positive electrode active material in this application, the molar content of Li is the initial state of the material, i.e., the state before feeding. After the positive electrode active material is applied to the battery system and undergoes charging and discharging cycles, the molar content of Li will change.

[0077] In some embodiments, when the battery is a sodium ion battery, the positive electrode active material can use a positive electrode active material known in the art for sodium ion batteries.

[0078] By way of example, the positive electrode active material can include at least one of the following materials: sodium transition metal oxides, polyanion compounds, and prussian blue type sodium compounds, and modified compounds of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. The modified compounds of each of the above materials can be a doping modification and / or a surface coating modification of the material.

[0079] In some embodiments, the transition metal in the sodium transition metal oxide can be at least one of Ti, V, Mn, Co, Ni, Fe, Zn, V, Zr, Ce, Cr, Cu. The chemical formula of the sodium transition metal oxide can satisfy Na xMO2, wherein M comprises at least one of Ti, V, Mn, Co, Ni, Fe, Zn, V, Zr, Ce, Cr, Cu, and 0 < x < 1.

[0080] In some embodiments, the polyanionic compound can be a compound having a sodium ion, a transition metal ion, and a tetrahedral (YO4) n- anion unit. The transition metal can include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y can include at least one of P, S, and Si; and n represents a valence of (YO4) n- .

[0081] In some embodiments, the polyanionic compound can also be a compound having a sodium ion, a transition metal ion, a tetrahedral (YO4) n- anion unit, and a halogen anion. The transition metal can include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y can include at least one of P, S, and Si; n represents a valence of (YO4) n- ; and the halogen can include at least one of F, Cl, and Br.

[0082] In some embodiments, the polyanionic compound can also be a compound having a sodium ion, a tetrahedral (YO4) n- anion unit, a polyhedral unit (ZO y ) m+ , and an optional halogen anion. M can include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y can include at least one of P, S, and Si; n represents a valence of (YO4) n- ; Z represents a transition metal; m represents a valence of (ZO y ) m+ ; and the halogen can include at least one of F, Cl, and Br.

[0083] As an example, the polyanionic compound can satisfy at least one of the chemical formulas NaFePO4, Na3V2(PO4)3(Na3V2P04, NVP for short), Na4Fe3(PO4)2(P2O7), NaM’PO4F (M’ includes at least one of V, Fe, Mn, and Ni), and Na3(VO y )2(PO4)2F 3-2y (0 < y < 1).

[0084] In some embodiments, the Prussian blue compound can be a compound having a sodium ion, a transition metal ion, and a cyanide ion (CN -The transition metal can include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce.

[0085] As an example, the Prussian blue type compound can satisfy the chemical formula Na a Me b Me’ c (CN)6, where Me and Me’ each independently include at least one of Ni, Cu, Fe, Mn, Co, Zn, 0

[0086] The battery is accompanied by Na deintercalation and consumption during charging and discharging, and the molar content of Na is different when the battery is discharged to different states. In the enumeration of the positive electrode active material in this application, the molar content of Na is the initial state of the material, i.e., the state before feeding. After the positive electrode active material is applied to the battery system and undergoes charging and discharging cycles, the molar content of Na will change.

[0087] In the enumeration of the positive electrode active material in this application, the molar content of O is only the theoretical state value, and the release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of O will fluctuate.

[0088] In some embodiments, the positive electrode active material layer can also optionally include a binder.

[0089] As an example, the binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic ester resin.

[0090] In some embodiments, the positive electrode active material layer can also optionally include a conductive agent.

[0091] As an example, the conductive agent can include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0092] [Negative electrode tab]

[0093] The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side surface of the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material.

[0094] As an example, the negative electrode current collector has two surfaces opposite in its own thickness direction, and the negative electrode active material layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0095] In some embodiments, the negative current collector can employ a metal foil or a composite current collector. For example, as a metal foil, a copper foil can be employed. The composite current collector can include a polymer material base layer and a metal layer formed on at least one side surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material base layer (e.g., a base layer of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0096] In some embodiments, the negative active material can employ a negative active material for a battery as known in the art. As an example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, etc. The silicon-based material includes at least one of elemental silicon, silicon oxide compound, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material includes at least one of elemental tin, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative active material for a battery can also be used. These negative active materials can be used alone or in combination of two or more.

[0097] In some embodiments, the negative active material layer can further optionally include a binder.

[0098] As an example, the binder in the negative active material layer can include at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0099] In some embodiments, the negative active material layer can further optionally include a conductive agent.

[0100] As an example, the conductive agent includes at least one of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dot, carbon nanotube, graphene, and carbon nanofiber.

[0101] In some embodiments, the negative active material layer can further optionally include other additives, such as a thickening agent (e.g., sodium carboxymethyl cellulose (CMC-Na)) and the like.

[0102] [Electrolyte]

[0103] The electrolyte serves to conduct ions between the positive electrode tab and the negative electrode tab. The present application does not have a specific limitation on the type of electrolyte, which can be selected as needed. For example, the electrolyte can be in a liquid state, a gel state, or a full solid state.

[0104] In some embodiments, the electrolyte employs an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0105] In some embodiments, the electrolyte salt includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorobisoxalate borate, lithium bisoxalate borate, lithium difluorobisoxalate phosphate, lithium tetrafluorobisoxalate phosphate.

[0106] In some embodiments, the solvent includes at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, diethyl sulfone.

[0107] In some embodiments, the electrolyte solution can also optionally include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can also include an additive capable of improving certain performance of the battery, such as an additive for improving overcharge performance of the battery, an additive for improving high-temperature or low-temperature performance of the battery, etc.

[0108] In some embodiments, the battery can include an outer package. The outer package can be used to package the electrode assembly and the electrolyte described above.

[0109] In some embodiments, the outer package of the battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the battery can also be a soft package, such as a pouch-type soft package. The material of the soft package can be plastic, and as plastic, polypropylene, polybutylene terephthalate, and polybutylene succinate, etc. can be listed.

[0110] In some embodiments, the battery can include at least one of a battery cell, a battery module, and a battery pack.

[0111] The shape of the battery is not particularly limited in the present application, and it can be cylindrical, square, or any other arbitrary shape. For example, FIG. 2 is a battery cell 5 of a square structure as an example.

[0112] In some embodiments, referring to FIG. 3, the outer package can include a housing 51 and a top cover assembly 53. The housing 51 can include a bottom plate and side plates connected to the bottom plate, which enclose a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the top cover assembly 53 can be arranged on the opening to close the receiving cavity. The positive electrode tab, the negative electrode tab, and the separator film can form an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is packaged in the receiving cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, which can be selected by those skilled in the art according to specific actual needs.

[0113] In some embodiments, the battery cell can be assembled into a battery module, and the number of battery cells contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0114] FIG. 4 is a battery module 4 as an example. Referring to FIG. 4, in the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, other arbitrary arrangements can also be used. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0115] Optionally, the battery module 4 can also include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0116] In some embodiments, the above-mentioned battery module can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0117] FIGS. 5 and 6 are a battery pack 1 as an example. Referring to FIGS. 5 and 6, the battery pack 1 can include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be arranged on the lower box body 3 to form a closed space for receiving the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0118] In the second aspect of the present application, a method for preparing the above-mentioned battery is provided, which includes:

[0119] S100: mixing an acrylate copolymer emulsion with a solution of a coating material

[0120] In some embodiments, the acrylate copolymer emulsion is mixed with a solution of a coating material to obtain a mixed slurry, wherein the coating material includes at least one of a water-soluble silicate and an anti-blocking agent.

[0121] In some embodiments, the coating material can be uniformly dispersed in deionized water, wherein the water-soluble silicate and the anti-caking agent (except for silicon dioxide) can be completely dissolved in water, which helps to form a film on the surface of the acrylate copolymer after spray drying.

[0122] In some embodiments, the acrylate copolymer emulsion can be prepared by emulsion polymerization and mixed with a solution containing the coating material to obtain a mixed slurry.

[0123] Emulsion polymerization is a process in which monomers are dispersed in water to form an emulsion with the help of emulsifiers and mechanical stirring, and then an initiator is added to initiate polymerization of the monomers.

[0124] Emulsifiers are substances that can convert incompatible oil and water into an emulsion that is difficult to separate. Emulsifiers are usually surface active agents that have both hydrophilic polar groups and hydrophobic (lipophilic) non-polar groups.

[0125] Initiators are substances that can initiate polymerization of monomers. For example, free radical initiators are a class of compounds that can easily decompose into free radicals (i.e. primary free radicals) by heat, which can be used to initiate free radical polymerization and copolymerization of olefinic and diene monomers.

[0126] In some embodiments, the emulsifier can include at least one of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium dodecyl benzene sulfate, sodium laurate, sodium stearate, and sodium palmitoleate.

[0127] In some embodiments, the initiator can include at least one of the following: a persulfate initiator including at least one of potassium persulfate and ammonium persulfate; an acyl peroxide initiator including at least one of benzoyl peroxide and di-n-octyl peroxide; and an azo initiator including at least one of azobisisobutyronitrile and dimethyl azobisisobutyrate.

[0128] S200: performing spray drying on the mixed slurry

[0129] In some embodiments, the binder can be obtained by spray drying the mixed slurry. Specifically, the water-soluble silicate is soluble in the mixed slurry, and during the spray drying process, the water-soluble silicate can form a protective layer on the surface of the acrylate latex, improving the processing performance of spray drying and increasing the yield of the powder; the anti-caking agent can form a protective layer on the surface of the acrylate latex during the spray drying process, effectively reducing the caking of the binder; and at the same time, the processing performance of spray drying can be improved and the yield of the powder can be increased.

[0130] In some embodiments, the mass fraction of the coating material in the solution of the coating material is 10%-30%. In this way, the mass fraction of the coating material in the binder is moderate, which can not only alleviate the self-adhesion of the acrylate copolymer, but also fully release the acrylate polymer under the action of pressure, thereby helping to obtain a binder with better performance.

[0131] For example, the mass fraction of the coating material in the solution of the coating material can be 10%, 15%, 20%, 25%, or 30%.

[0132] For example, when the coating material is a water-soluble silicate, the mass fraction of the water-soluble silicate in the solution of the coating material is 10%-30%.

[0133] For example, when the coating material is an anti-blocking agent, the mass fraction of the anti-blocking agent in the solution of the coating material is 10%-30%.

[0134] Spray drying is a process in which the material to be dried is dispersed into very fine mist-like particles by mechanical action (increasing the water evaporation area and accelerating the drying process), and most of the water is removed in the instant of contact with hot air, so that the solid material in the material is dried into a powder.

[0135] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder, and any other components, in a solvent (such as N-methyl pyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on a positive electrode current collector, and then performing processes such as drying and cold pressing to obtain the positive electrode sheet.

[0136] In some embodiments, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder, and any other components, in a solvent (such as deionized water) to form a negative electrode slurry; coating the negative electrode slurry on a negative electrode current collector, and then performing processes such as drying and cold pressing to obtain the negative electrode sheet.

[0137] In some embodiments, the polymer is arranged on at least one side of the base film, for example. The polymer can be formed on one side of the base film by spraying to obtain the separator film.

[0138] In some embodiments, the separator film is arranged between the positive electrode sheet and the negative electrode sheet, and the battery is assembled. Specifically, the positive electrode sheet, the negative electrode sheet, and the separator film can be made into an electrode assembly by a winding process or a stacking process. Subsequently, the roll pressing process is performed to obtain the battery. In this way, the separator film can better bond the adjacent electrode sheets.

[0139] In a third aspect of the present application, a power consuming device is provided, which comprises the battery as described above. Thus, the power consuming device has all the features and advantages of the battery as described above, which will not be repeated here.

[0140] The power consuming device can comprise at least one of the battery cell, the battery module, and the battery pack provided by the present application. The battery cell, the battery module, and the battery pack can be used as a power source of the power consuming device, or can be used as an energy storage unit of the power consuming device. The power consuming device can comprise a mobile device (e.g., a mobile phone, a laptop, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc.

[0141] As the power consuming device, the battery cell, the battery module, or the battery pack can be selected according to the use requirement thereof.

[0142] The scheme of the present application will be described below by means of specific examples. It should be noted that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the examples, the technology or condition described in the literature in the art or according to the product manual is used. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by purchase.

[0143] Example 1

[0144] Preparation of the acrylate copolymer emulsion:

[0145] According to the mass ratio of the three monomers 0.25:1:0.12, the styrene (first monomer): ethyl acrylate (second monomer): acrylamide (third monomer) was weighed and mixed uniformly. In a 1000 mL four-necked flask equipped with mechanical stirring, a thermometer and a condenser, 300 g of mixed monomers, 6 g of sodium dodecyl sulfate emulsifier, 2.2 g of ammonium persulfate initiator, and 360 g of deionized water were added, and emulsified at high speed for 30 min. Under nitrogen protection, the temperature was raised to 75°C and reacted for 4 h, then cooled to below 40°C, and the pH was adjusted to neutral with sodium hydroxide. The filtrate was obtained to give the acrylate copolymer emulsion.

[0146] Preparation of the solution of the coating material:

[0147] The coating material was sodium silicate, the solvent was deionized water, and the mass fraction of the coating material in the solution of the coating material was 20%.

[0148] Preparation of the mixed slurry:

[0149] The acrylate copolymer emulsion and the aqueous solution of the coating material were mixed uniformly at a mass ratio (calculated according to the solid content) of 100:1.

[0150] Preparation of the binder:

[0151] The mixed slurry was subjected to spray drying to obtain the binder. Specifically, the spray drying adopted a centrifugal spray process, the inlet air temperature was 115°C, the outlet air temperature was 60°C, and the air pressure was 0.3 MPa.

[0152] Preparation of the separator film:

[0153] A commercially available PE microporous film (from Zhuogao Electronics Technology Co., Ltd.) with a thickness of 7 pm and an average pore size of 80 nm was used as the base film. The above binder was stirred and mixed uniformly in deionized water to obtain a slurry (solid content of 20%). The slurry was uniformly coated on both surfaces of the base film, and the solvent was removed by drying. The coating density of the binder on the base film was 1 g / m 2 , to obtain the separator film.

[0154] The remaining examples, comparative examples, and example 1 are consistent, and the differences are shown in Table 1.

[0155] Table 1

[0156] The foregoing separator film was assembled to obtain a battery. Specifically,

[0157] Preparation of the positive electrode sheet:

[0158] Polyvinylidene fluoride (PVDF), lithium iron phosphate (LFP), conductive agent carbon black, and N-methyl pyrrolidone (NMP) were mixed uniformly at a mass ratio of 1.2:58.38:0.42:40 to prepare a positive electrode slurry. The positive electrode slurry was uniformly coated on the positive electrode current collector aluminum foil at a loading of 200 g / m 2 , followed by drying, cold pressing, and slitting to obtain the positive electrode sheet.

[0159] Preparation of the negative electrode sheet:

[0160] Artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), and thickening agent sodium carboxymethyl cellulose (CMC-Na) were added to deionized water at a mass ratio of 96.2:1.0:1.6:1.2, and fully stirred and mixed uniformly to prepare a negative electrode slurry (solid content of 63%). The negative electrode slurry was coated on the negative electrode current collector copper foil at a loading of 98 g / m 2 , followed by drying, cold pressing, and slitting to obtain the negative electrode sheet.

[0161] Preparation of the electrolyte:

[0162] Ethylene carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain a mixed solvent at 25°C, and then LiPF6 was dissolved in the mixed solvent to obtain an electrolyte, wherein the concentration of LiPF6 was 1 mol / L.

[0163] Preparation of the battery

[0164] The above positive electrode sheet, separator, and negative electrode sheet were stacked in order and wound and cold-pressed to form (during which the separator was bonded to the electrode sheets) to obtain an electric core; the electric core was placed in an outer package, the electrolyte prepared above was added, and after processes such as packaging, standing, formation, and aging, a battery was obtained.

[0165] The aforementioned polymer and battery were tested as follows, and the test results are shown in Table 2:

[0166] Binder particle size test: a laser particle size analyzer (MasterSizer 3000) was used for testing, and a helium-neon red light source was used as the main light source. A clean small beaker was taken and 1 g of the sample to be tested was added, a drop of surfactant was added, 20 ml of deionized water was added, and ultrasonic treatment was performed at 53 KHz / 120 W for 5 min to ensure complete dispersion of the sample. After turning on the laser particle size analyzer and cleaning the light path system, the background was automatically tested. The measured solution was stirred to ensure uniform dispersion, and was placed in the sample cell as required, and the particle size was measured. The measurement results can be read from the instrument.

[0167] Swelling test: 10 g of the binder was added to 90 g of NMP solvent, and stirring was performed until the solute was completely dissolved, the solution was clear and transparent, and the solution was poured into aluminum foil paper and dried in an oven at a temperature of 70°C for 3 days to obtain a dried adhesive film; the adhesive film with a mass of m1 was placed in an electrolyte and soaked for 7 days at a temperature of 70°C. After the time was up, it was taken out, wiped, and weighed as m2. Through calculation, the swelling rate w of the adhesive film was obtained as (m2-m1) / m1 x 100%, wherein the electrolyte was the electrolyte prepared above.

[0168] Cold pressure bonding force: Overlap the negative electrode sheet and the separator together, and place them on a hot press. Set the hot press parameters as follows: temperature 25°C, pressure 7 t, and time 15 s. Press to obtain a bonded separator / negative electrode sheet sample. Cut the separator / electrode sheet sample into a 150 mm x 20 mm rectangular sample. Paste one side of the above rectangular sample to a steel plate using double-sided tape. Separate the separator and the electrode sheet by 2 cm in length at one end of the rectangular sample to obtain a test sample. Keep the steel plate horizontal and fix it with the lower clamp of a universal testing machine (Coer Strong Instrument Manufacturing (Shanghai) Co., Ltd., model CTM2100). Fix the peeled end of the separator as described above with the upper clamp of the universal testing machine and connect it to a tensile machine. Set the test conditions as follows: tensile rate 20 mm / min and horizontal pulling by 10 cm. After the tension is stable, record the tension value. The bonding force of the separator and the electrode sheet is obtained by dividing the tension value by the sample width.

[0169] Separator self-bonding force test: Overlap two pieces of separator together, and place them on a hot press. Set the hot press parameters as follows: temperature 25°C, pressure 10 t, and time 120 s. Press to obtain a bonded separator / separator sample. Cut the sample into a 150 mm x 20 mm rectangular sample. Paste one side of the above rectangular sample to a steel plate using double-sided tape. Separate the sample by 2 cm in length at one end of the rectangular sample to obtain a test sample. Keep the steel plate horizontal and fix it with the lower clamp of a universal testing machine (Coer Strong Instrument Manufacturing (Shanghai) Co., Ltd., model CTM2100). Fix the peeled end of the separator as described above with the upper clamp of the universal testing machine and connect it to a tensile machine. Set the test conditions as follows: tensile rate 20 mm / min and horizontal pulling by 10 cm. After the tension is stable, record the tension value. The self-bonding force of the separator is obtained by dividing the tension value by the sample width.

[0170] Battery cycle performance test: Apply a clamp force of 10,000 N to the battery. Perform cycle tests under this condition. The test procedure is as follows: at 25°C, charge the battery to 3.8 V at 1 / 3 C, then charge to a current of 0.05 C at 3.8 V constant voltage, stand for 5 min, then discharge to 2.0 V at 1 / 3 C. The obtained discharge capacity is recorded as initial capacity Co. Repeat the above steps for the same battery and record the discharge capacity of the battery after the nth cycle Cn. n Then the capacity retention rate P of the battery after each cycle is n = (Cn / C0) x 100%. The cycle performance difference can be reflected by the capacity retention rate of the battery after 500 cycles. n

[0171] Table 2 ​

[0172] The test results show that the coating material on the surface of the polymer in Examples 1-13 can effectively prevent direct contact and adhesion between the acrylate copolymer particles, and reduce the occurrence of self-adhesion of the separator film. After the separator film is wound with the pole piece and subjected to cold pressing, the adhesive shows better adhesion characteristics, and the battery has better cycle performance. In addition, the better anti-swelling ability of the coating material also helps to improve the anti-swelling property of the adhesive.

[0173] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect as the technical idea within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A battery, wherein, The battery comprises: a separator film, the separator film comprising a base film and an adhesive located on at least one side of the base film, the adhesive comprising: a core, the core comprising an acrylate copolymer; a coating material, the coating material at least partially covering the surface of the core, the coating material comprising at least one of a water-soluble silicate and an anti-blocking agent, the mass ratio of the core to the coating material being 100:(0.1-20).

2. The battery of claim 1, wherein, The mass ratio of the core to the coating material is 100:(2-15).

3. The battery according to claim 1 or 2, wherein The water-soluble silicate comprises at least one of sodium silicate, potassium silicate, lithium silicate, calcium silicate, magnesium silicate, sodium aluminum silicate, a silicate and a water-soluble organic polymer compound, wherein the water-soluble organic polymer comprises at least one of polyacrylic acid, polyacrylamide, and polyvinyl alcohol.

4. The battery according to claim 1 or 2, wherein The anti-blocking agent comprises at least one of potassium ferrocyanide, tricalcium phosphate, silicon dioxide, ferric tartrate, ferric ammonium citrate, and microcrystalline cellulose.

5. The battery of any one of claims 1-4, wherein, The monomers of the acrylate copolymer comprise a first monomer, a second monomer, and a third monomer, The first monomer comprises at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, trimethylolpropane triacrylate, acrylonitrile, methacrylonitrile, ethyl acrylonitrile, vinyl acetate, styrene, butadiene, and isoprene. The second monomer comprises at least one of ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isooctyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate. The third monomer comprises at least one of acrylic acid, methacrylic acid, butenyl acid, heptenyl acid, itaconic acid, maleic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylamide, and N-methylol acrylamide.

6. The battery of claim 5, wherein, The mass ratio of the first monomer, the second monomer, and the third monomer in the acrylate copolymer is (0.1-0.4):1:(0.1-0.2).

7. The battery of any one of claims 1-6, wherein, The Dv50 particle size of the adhesive is 5-25 μm.

8. A method of making the battery of any one of claims 1-7, wherein, The battery comprises: mixing an acrylate copolymer emulsion and a solution of a coating material to obtain a mixed slurry, wherein the coating material comprises at least one of a water-soluble silicate and an anti-blocking agent; spray drying the mixed slurry to obtain an adhesive; arranging the adhesive on at least one side of a base film to obtain a separator film, and obtaining a battery.

9. The method of claim 8, wherein, The mass fraction of the coating material in the solution of the coating material is 10%-30%.

10. The method of claim 8 or 9, wherein, Arranging the separator film between a positive electrode sheet and a negative electrode sheet, and performing cold pressing to obtain the battery.

11. An electrical device, comprising: The battery comprises any one of the batteries of claims 1-7, or is prepared by any one of the methods of claims 8-10.

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