Battery shell, preparation method and battery

Abstract

The embodiment of the invention provides a battery shell, a preparation method and a battery, and relates to the technical field of batteries. The battery shell comprises a shell and an insulating heat-conducting coating coated in the shell, wherein the insulating heat-conducting coating consists of an insulating heat-conducting glue material and a high-heat-conductivity material. Through the insulating heat-conducting coating, the temperature rise in the rapid charging process of the battery is effectively reduced, electrolyte decomposition and safety risks caused by high temperature are prevented, and the heat management capability, the cycle performance and the safety of the battery are improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery casing, a preparation method and a battery. Background Art

[0002] Lithium-ion batteries are widely used in consumer electronics, electric vehicles, energy storage systems, etc. due to their high energy density, long cycle life and low self-discharge rate. At the same time, with the development of technology and the improvement of market application requirements, the fast charging performance of batteries has become a strong competitive point.

[0003] During fast charging, the current density inside the battery increases significantly, causing the reaction between the electrode material and the electrolyte to intensify, generating a large amount of heat and causing the battery temperature to rise rapidly. In current battery applications, especially in electric vehicles and large energy storage systems, battery packs usually manage heat dissipation by adding a liquid cooling system at the bottom. When the fast charging performance of the battery is improved, the speed of the electrochemical reaction inside the battery is significantly accelerated, resulting in increased heat generation. The bottom liquid cooling system cannot dissipate the heat in a timely and effective manner, causing the battery temperature to rise rapidly. At the same time, it may lead to the decomposition of the electrolyte and the occurrence of a series of side reactions, which consumes the electrolyte, reduces the battery's liquid retention, and increases the internal pressure and safety risks of the battery.

[0004] In summary, providing a technical solution to improve battery safety performance during fast charging is a technical solution that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide a battery case, a preparation method and a battery, which are used to effectively reduce the temperature rise of the battery during rapid charging, prevent electrolyte decomposition and safety risks caused by high temperature, and improve the thermal management capability, cycle performance and safety of the battery.

[0006] In a first aspect, an embodiment of the present application provides a battery case, comprising: a case and an insulating thermally conductive coating coated inside the case, wherein the insulating thermally conductive coating is composed of an insulating thermally conductive adhesive material and a high thermal conductivity material.

[0007] In a possible implementation manner, the thickness of the insulating thermal conductive coating is 0.05 mm-0.3 mm.

[0008] In a possible implementation, the insulating thermally conductive adhesive material is acrylic emulsion.

[0009] In a possible implementation, the high thermal conductivity material is aluminum nitride particles or boron nitride particles.

[0010] In a possible implementation, in the insulating and heat-conducting coating, the dosage ratio of aluminum nitride particles to the acrylic emulsion is 0.1% - 5%; or, the dosage ratio of boron nitride particles to the acrylic emulsion is 0.1% - 5%.

[0011] In a second aspect, an electrode core provided by an embodiment of the present application is a positive electrode sheet, a negative electrode sheet, and a separator are made by a stacking or winding method, and the outside of the electrode core is not wrapped with a mylar film.

[0012] In a third aspect, an embodiment of the present application provides a battery, including:

[0013] The battery case described in the first aspect, and an electrode core, an electrolyte, and a structural member that are not wrapped with a mylar film and are arranged inside the battery case.

[0014] In a fourth aspect, an embodiment of the present application provides a method for preparing a battery case, including:

[0015] Adding a high thermal conductivity material to an insulating and heat-conducting adhesive material to obtain a mixed slurry;

[0016] Spraying the mixed slurry inside the case to obtain the battery case described in the first aspect.

[0017] In a possible implementation, the insulating and heat-conducting adhesive material is an acrylic emulsion, and adding a high thermal conductivity material to the insulating and heat-conducting adhesive material to obtain a mixed slurry includes:

[0018] Adding a high thermal conductivity material to the acrylic emulsion to obtain an acrylic slurry as the mixed slurry.

[0019] In a possible implementation, the high thermal conductivity material is aluminum nitride particles or boron nitride particles, and adding a high thermal conductivity material to the acrylic emulsion includes:

[0020] Adding boron nitride particles or aluminum nitride particles to the acrylic emulsion, wherein the dosage ratio of the aluminum nitride particles to the acrylic emulsion is 0.1% - 5%; or, the dosage ratio of the boron nitride particles to the acrylic emulsion is 0.1% - 5%.

[0021] A battery case, a preparation method, and a battery provided by an embodiment of the present application significantly improve the thermal management ability of the battery through an insulating and heat-conducting coating applied inside the battery case, can effectively reduce the temperature rise during fast charging, and prevent the decomposition of the electrolyte and safety risks caused by high temperature. At the same time, the insulating and heat-conducting coating applied inside the battery case can replace the traditional mylar polyester film, which not only improves the production efficiency and battery energy density, enhances the insulation protection of the electrode core, but also improves the cycle performance and safety of the battery. Description of the Drawings

[0022] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0023] Figure 1 A schematic structural diagram of a battery housing provided for this application;

[0024] Figure 2 A schematic diagram of a specific implementation manner of a battery housing provided for this application;

[0025] Figure 3 A process schematic of a preparation method of a battery housing provided for this application.

[0026] Through the above accompanying drawings, clear embodiments of this application have been shown, and there will be more detailed descriptions hereinafter. These accompanying drawings and written descriptions are not intended to limit the scope of the concept of this application in any way, but to illustrate the concept of this application to those skilled in the art by referring to specific embodiments. Specific Embodiments

[0027] To enable those skilled in the art to better understand the solution of this invention, the following further details this invention. The specific embodiments listed below only describe the principles and features of this invention, and the examples given are only used to explain this invention and do not limit the scope of this invention. Based on the embodiments of this invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this invention.

[0028] First, the terms involved in this application are explained:

[0029] Mylar film: A polyester film made of polyethylene terephthalate (PET), widely used in batteries, especially for wrapping battery cores. Its main function is to provide electrical insulation and mechanical protection, preventing internal short circuits and external physical damage in the battery. Mylar film has good chemical resistance and can resist electrolyte leakage or erosion by other chemical substances. In addition, its thermal stability and dimensional stability enable it to maintain the integrity of its shape and function under various temperature conditions, thereby improving the safety and reliability of the battery. By using Mylar film, the battery can operate in a harsh environment and extend its service life.

[0030] Next, the application background of this application is explained as follows:

[0031] As an advanced energy storage technology, lithium-ion batteries have become the core components of modern electronic devices and electric vehicles due to their high energy density, long cycle life, and low self-discharge rate. The long cycle life ensures that the battery can still maintain a high capacity after multiple charge and discharge cycles, which is crucial for electric vehicles and energy storage systems as they need to maintain stable performance and reliability over a long usage period.

[0032] With the continuous progress of technology and the change of market demand, the fast charging performance of lithium-ion batteries has become a new competitive focus. The improvement of fast charging technology can significantly shorten the charging time and greatly improve the user experience. Especially in the field of electric vehicles, fast charging can reduce the vehicle's stay time, improve travel efficiency, and thus promote the popularization of electric vehicles. During the fast charging process, the current density inside the battery increases significantly, leading to an intensified reaction between the electrode material and the electrolyte, generating a large amount of heat and causing the battery temperature to rise rapidly. Therefore, an effective thermal management system is needed to control the battery temperature and ensure its operation within a safe range. The improvement of fast charging performance is not only an embodiment of technological innovation but also an important indicator of market competitiveness, driving the continuous development and application expansion of lithium-ion battery technology.

[0033] In current battery applications, especially in electric vehicles and large-scale energy storage systems, the battery pack is usually cooled by adding a liquid cooling system at the bottom for heat dissipation management. When the fast charging performance of the battery is improved, the battery will generate more heat, and the temperature of some batteries will exceed 70°C. The electrochemical reaction rate inside the battery will increase significantly, resulting in side reactions. At the same time, it may cause the decomposition of the electrolyte and a series of side reactions to occur, consuming the electrolyte, reducing the liquid retention capacity of the battery, increasing the internal pressure of the battery, and increasing the safety risk.

[0034] In summary, providing a technical solution to improve the battery safety performance during fast charging, enhancing the battery's thermal management ability, effectively reducing the temperature rise during fast charging, and preventing the decomposition of the electrolyte and safety risks caused by high temperature is an urgent technical problem to be solved.

[0035] Based on the above technical problems, during the research on battery material modification and force system optimization, the inventor found that by coating an insulating and heat-conducting coating inside the battery housing, not only can the temperature rise during fast charging be effectively reduced, preventing the decomposition of the electrolyte and safety risks caused by high temperature, but also the traditional mylar polyester film can be replaced by the insulating and heat-conducting coating to improve production efficiency and battery energy density, enhance the insulation protection of the electrode core, and improve the cycle performance and safety of the battery. Based on this, the present application provides a battery housing, a preparation method, and a battery.

[0036] Figure 1 The structural schematic diagram of a battery housing provided by the present application Figure 2Schematic diagram of a specific implementation manner of a battery housing provided for this application, as Figure 1 shown, the battery housing includes a housing 10 and an insulating and heat-conducting coating 11 coated inside the housing. The insulating and heat-conducting coating 11 is composed of an insulating and heat-conducting adhesive material and a high heat-conducting material.

[0037] In a possible implementation manner, as Figure 2 shown, the insulating and heat-conducting adhesive material is acrylic emulsion, and the high heat-conducting material is aluminum nitride particles or boron nitride particles.

[0038] The acrylic emulsion is a milky white or nearly transparent viscous liquid, which is an emulsion copolymerized from pure acrylate monomers, and is a kind of emulsion with small particle size, multiple uses and excellent performance. It has outstanding water resistance and chemical resistance, and has good adhesion to the surfaces of masonry, wood and steel, etc., and the viscosity is 50 - 500 mPa s.

[0039] Both aluminum nitride and boron nitride are high-performance heat-conducting materials. The thermal conductivity of aluminum nitride can reach 310 W / m K at room temperature, far exceeding that of alumina with a thermal conductivity of about 20 - 35 W / m K, silicon nitride with a thermal conductivity of about 20 - 30 W / m K, magnesium oxide with a thermal conductivity of about 35 - 60 W / m K, zinc oxide with a thermal conductivity of about 50 - 60 W / m K, silicon oxide with a thermal conductivity of about 1.3 W / m K, and beryllium oxide with a thermal conductivity of about 200 - 300 W / m K, making aluminum nitride an ideal heat sink material. And boron nitride, especially cubic boron nitride, has a thermal conductivity of up to 600 - 700 W / m K. At the same time, since boron nitride or aluminum nitride itself is insulating and non-conductive, and the resistivity of boron nitride is , the resistivity of aluminum nitride is , comparable to that of acrylic with a resistivity of and mylar film with a component of PET and a resistivity of , so boron nitride particles or aluminum nitride particles will not reduce the insulation of the insulating and heat-conducting coating itself.

[0040] In a possible implementation manner, in the insulating and heat-conducting coating, the dosage ratio of aluminum nitride particles to acrylic emulsion is 0.1% - 5%; or, the dosage ratio of boron nitride particles to acrylic emulsion is 0.1% - 5%.

[0041] By adding an appropriate amount of high - thermal - conductivity materials, such as boron nitride particles or aluminum nitride particles with a particle size of 100 nm, to the insulating material, the thermal conductivity of the insulating thermal - conductive coating can be significantly improved, thereby effectively conducting the heat generated during the rapid charging of the battery to the outside of the battery case and reducing the overall temperature rise of the battery. Regarding the dosages of the insulating material and the high - thermal - conductivity material, it is necessary to ensure the balance among the thermal conductivity, insulation property, and adhesion of the insulating thermal - conductive coating. Too low a content of the high - thermal - conductivity material may not provide sufficient thermal conductivity, while too high a content of the high - thermal - conductivity material may affect the adhesiveness and flexibility of the insulating thermal - conductive coating, and may even cause cracking or peeling of the insulating thermal - conductive coating.

[0042] The addition ratio of boron nitride particles or aluminum nitride particles is 0.1% - 5% of the mass of the acrylic emulsion, such as 0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%. That is, when the mass fraction of the acrylic emulsion is 1 part, the mass fractions of boron nitride particles or aluminum nitride particles can be 0.001 part, 0.002 part, 0.005 part, 0.01 part, 0.02 part, 0.03 part, 0.04 part, and 0.05 part respectively. The thermal conductivity of the insulating thermal - conductive coating can be controlled by the addition amount of boron nitride or aluminum nitride particles. As can be seen from the above, due to the excellent thermal conductivity of boron nitride particles or aluminum nitride particles, the addition amount of only 0.1% - 5% of the mass of the acrylic emulsion is sufficient to significantly improve the thermal conductivity of the insulating thermal - conductive coating, thereby effectively conducting the heat generated during the rapid charging of the battery to the outside of the battery case and reducing the overall temperature rise of the battery.

[0043] In a possible implementation, the thickness of the insulating thermal - conductive coating is 0.05 mm - 0.3 mm.

[0044] Exemplarily, the thickness of the insulating thermal - conductive coating can be 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, etc. This not only ensures that the insulating thermal - conductive coating has good mechanical strength, durability, and flexibility, enabling it to effectively adhere to the inside of the battery case. Secondly, this thickness is equivalent to that of the mylar film traditionally used to wrap the electrode core, and the hardness of the insulating coating is higher than that of the mylar film. Therefore, it can directly replace the mylar film without changing the existing battery design, reducing the space in the overlapping area of the mylar film, increasing the remaining space in the case, and improving the battery energy density.

[0045] A battery housing provided by an embodiment of the present application effectively improves the thermal management ability of the battery by coating an insulating and thermally conductive coating composed of an insulating thermally conductive adhesive and a highly thermally conductive material inside the battery housing. Specifically, the insulating thermally conductive adhesive material is selected as acrylic emulsion, and the highly thermally conductive material is selected as aluminum nitride or boron nitride particles and added in a proportion of 0.1% - 5% of the mass of the acrylic emulsion. By making full use of their excellent thermal conductivity, the thermal conductivity coefficient of the coating is significantly improved. Through the above battery housing, the heat generated during the fast charging process of the battery is effectively conducted to the outside of the battery housing quickly, reducing the overall temperature rise of the battery and ensuring the safety and reliability of the battery, providing an innovative solution for the efficient heat dissipation and safe operation of the battery.

[0046] Figure 3 The flow chart of a preparation method of a battery housing provided for this application is shown as Figure 3 shown. The preparation method of this battery housing specifically includes the following steps:

[0047] S301: Add a highly thermally conductive material to the insulating thermally conductive adhesive material to obtain a mixed slurry.

[0048] Specifically, select acrylic emulsion as the insulating thermally conductive adhesive material, and select aluminum nitride particles or boron nitride particles as the highly thermally conductive material, that is, add boron nitride particles or aluminum nitride particles to the acrylic emulsion to obtain acrylic slurry as the mixed slurry. It should be noted that the dosage ratio of aluminum nitride particles to acrylic emulsion is 0.1% - 5%; or, the dosage ratio of boron nitride particles to acrylic emulsion is 0.1% - 5%. By adding aluminum nitride particles or boron nitride particles to the acrylic emulsion, the thermal conductivity of the mixed slurry can be significantly improved without significantly affecting the insulating performance of the acrylic emulsion.

[0049] S302: Spray the mixed slurry inside the housing to obtain a battery housing.

[0050] Specifically, evenly spray the acrylic slurry inside the battery housing. After the acrylic slurry dries, an insulating and thermally conductive coating is formed to obtain a battery housing, and the thickness of this insulating and thermally conductive coating is 0.05 mm - 0.3 mm.

[0051] A method for preparing a battery housing provided by an embodiment of the present application prepares a mixed slurry with excellent thermal conductivity by adding high thermal conductivity materials such as aluminum nitride particles or boron nitride particles to an acrylic emulsion, and uniformly sprays this mixed slurry inside the battery housing, and forms an insulating and thermally conductive coating with a thickness of 0.05 mm - 0.3 mm after drying, thereby obtaining a battery housing with excellent thermal management capabilities. Through the above method, not only the heat dissipation efficiency of the battery housing is improved, the performance and reliability of the battery are enhanced, but also good insulation characteristics are maintained, which is suitable for wide application in electronic devices. The overall preparation process is simple, the cost is controllable, and it is suitable for large-scale production.

[0052] The present application also provides an electrode core, which is made by laminating or winding a positive electrode sheet, a negative electrode sheet, and a separator, and the outside of the electrode core is not wrapped with a mylar film.

[0053] Specifically, a conventional positive electrode sheet, a negative electrode sheet, and a separator are made into an electrode core by laminating or winding, and are formed by high-temperature hot pressing. It should be noted that the outside of the electrode core is not wrapped with a mylar film before being connected to the cover plate and put into the battery housing.

[0054] As Figure 1 As described in the embodiment, since the hardness of the insulating and thermally conductive coating is higher than that of the mylar film, the coating provides better overall insulation protection for the electrode core, and can prevent the outer mylar film from being scratched when the traditional electrode core is put into the housing. The insulating and thermally conductive coating directly replaces the mylar film, and also reduces the process of wrapping the mylar film around the electrode core during battery production. Without using the mylar film, it can also improve the wetting of the electrolyte on the electrode core, shorten the wetting time, and improve the production efficiency of the battery. In addition, since the mylar film has an opening area or an overlapping area, it cannot completely prevent the electrode core from contacting the housing, which may corrode the housing. Replacing the mylar film with the insulating and thermally conductive coating can completely avoid the contact between the electrode core and the housing and the occurrence of housing corrosion, further ensuring the safety and reliability of the battery.

[0055] The present application also provides a battery, including: as Figure 1 the battery housing described in the embodiment and the electrode core, electrolyte, and structural components disposed inside the battery housing without being wrapped with a mylar film.

[0056] Specifically, the positive and negative electrode tabs of the electrode core described in the previous embodiment are welded to the positive and negative electrode cover plates, and are disposed inside the battery housing, and the electrolyte is injected, and a lithium-ion battery is formed through processes such as formation and grading. Among them, the electrode core, electrolyte, and structural components are all inside the battery housing. The battery can be in the shape of a blade, a square, or other shapes, which is not specifically limited in the present application.

[0057] The following will specifically introduce the battery housing, preparation method, and application of the battery provided by the present application through specific embodiments.

[0058] Unless otherwise specified, the reagents, materials, and instruments used in the following examples are all conventional reagents, conventional materials, and conventional instruments in the art, which can be obtained through commercial purchase, and the reagents involved can also be obtained by conventional methods in the art.

[0059] In the following examples and comparative examples, the battery fast charging cycle test method is as follows: Adopt the stepped fast charging mode, the average charging current is 4C, the average discharge current is 1C, the voltage range is 2.0V - 3.75V. After 800 cycles, calculate the capacity retention rate of the battery after 800 cycles and detect the temperature at the middle position of the large surface of the battery.

[0060] The battery thermal runaway test method is as follows: Assemble the battery described in the above example into a module, heat a specified single cell until thermal runaway occurs in the cell, and observe whether the cell explodes.

[0061] The specific example parameters of the examples and comparative examples are shown in Table 1:

[0062] Table 1 Specific example parameters of examples and comparative examples

[0063]

[0064] Example 1

[0065] This example provides a battery, including a battery housing coated with an insulating and heat-conducting coating, and a cell core, electrolyte, and structural components arranged inside the battery housing without being wrapped with mylar film. The thickness of the insulating and heat-conducting coating is 0.1mm, and its preparation method includes the following steps:

[0066] (1) Add boron nitride particles with a mass fraction of 0.001 to the insulating and heat-conducting adhesive material acrylic emulsion with a mass fraction of 1, and mix to obtain a mixed slurry acrylic slurry;

[0067] (2) Uniformly spray the acrylic slurry inside the battery housing. After the acrylic slurry dries, an insulating and heat-conducting coating is formed to obtain the battery housing, and the thickness of the insulating and heat-conducting coating is 0.1mm;

[0068] (3) Make the conventional positive electrode sheet, negative electrode sheet, and separator into a cell core by the method of laminating or winding, and form it by high-temperature hot pressing;

[0069] (4) Weld the positive and negative electrode tabs of the cell core to the positive and negative electrode covers, set them inside the battery housing, inject the electrolyte, and manufacture a lithium-ion battery through processes such as formation and grading.

[0070] Example 2

[0071] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1. The difference lies in that: in step (1), 0.005 parts by mass of a high heat-conductivity material, boron nitride particles, is added to 1 part by mass of an insulating and heat-conducting adhesive material, acrylic emulsion, and the mixture is mixed to obtain a mixed slurry, acrylic slurry.

[0072] Embodiment 3

[0073] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1. The difference lies in that: in step (1), 0.01 parts by mass of a high heat-conductivity material, boron nitride particles, is added to 1 part by mass of an insulating and heat-conducting adhesive material, acrylic emulsion, and the mixture is mixed to obtain a mixed slurry, acrylic slurry.

[0074] Embodiment 4

[0075] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1. The difference lies in that: in step (1), 0.02 parts by mass of a high heat-conductivity material, boron nitride particles, is added to 1 part by mass of an insulating and heat-conducting adhesive material, acrylic emulsion, and the mixture is mixed to obtain a mixed slurry, acrylic slurry.

[0076] Embodiment 5

[0077] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1. The difference lies in that: in step (1), 0.03 parts by mass of a high heat-conductivity material, boron nitride particles, is added to 1 part by mass of an insulating and heat-conducting adhesive material, acrylic emulsion, and the mixture is mixed to obtain a mixed slurry, acrylic slurry.

[0078] Embodiment 6

[0079] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1, except that: in step (1), 0.04 parts by mass of high heat-conducting material boron nitride particles are added to 1 part by mass of the insulating and heat-conducting adhesive material acrylic emulsion to obtain a mixed slurry acrylic slurry.

[0080] Embodiment 7

[0081] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1, except that: in step (1), 0.05 parts by mass of high heat-conducting material boron nitride particles are added to 1 part by mass of the insulating and heat-conducting adhesive material acrylic emulsion to obtain a mixed slurry acrylic slurry.

[0082] Embodiment 8

[0083] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method includes the following steps:

[0084] (1) 0.001 parts by mass of high heat-conducting material aluminum nitride particles are added to 1 part by mass of the insulating and heat-conducting adhesive material acrylic emulsion to obtain a mixed slurry acrylic slurry;

[0085] (2) The acrylic slurry is evenly sprayed inside the battery case. After the acrylic slurry dries, an insulating and heat-conducting coating is formed to obtain the battery case, and the thickness of the insulating and heat-conducting coating is 0.1 mm;

[0086] (3) A conventional positive electrode sheet, a negative electrode sheet, and a separator are made into a pole core by laminating or winding, and are formed by high-temperature hot pressing;

[0087] (4) The positive and negative electrode tabs of the pole core are welded to the positive and negative electrode covers, and are disposed inside the battery case, and an electrolyte is injected, and a lithium-ion battery is formed through processes such as formation and grading.

[0088] Embodiment 9

[0089] This embodiment provides a battery, which includes a battery housing coated with an insulating and thermally conductive coating, and a pole core, an electrolyte, and a structural member disposed inside the battery housing without being wrapped with a mylar film. The thickness of the insulating and thermally conductive coating is 0.1 mm, and its preparation method is basically the same as that of Example 8, except that: in step (1), 0.005 parts by mass of high-thermal-conductivity aluminum nitride particles are added to 1 part by mass of the insulating and thermally conductive adhesive material acrylic emulsion, and the mixture is mixed to obtain a mixed slurry acrylic slurry.

[0090] Example 10

[0091] This embodiment provides a battery, which includes a battery housing coated with an insulating and thermally conductive coating, and a pole core, an electrolyte, and a structural member disposed inside the battery housing without being wrapped with a mylar film. The thickness of the insulating and thermally conductive coating is 0.1 mm, and its preparation method is basically the same as that of Example 1, except that: in step (1), 0.01 parts by mass of high-thermal-conductivity aluminum nitride particles are added to 1 part by mass of the insulating and thermally conductive adhesive material acrylic emulsion, and the mixture is mixed to obtain a mixed slurry acrylic slurry.

[0092] Example 11

[0093] This embodiment provides a battery, which includes a battery housing coated with an insulating and thermally conductive coating, and a pole core, an electrolyte, and a structural member disposed inside the battery housing without being wrapped with a mylar film. The thickness of the insulating and thermally conductive coating is 0.1 mm, and its preparation method is basically the same as that of Example 1, except that: in step (1), 0.02 parts by mass of high-thermal-conductivity aluminum nitride particles are added to 1 part by mass of the insulating and thermally conductive adhesive material acrylic emulsion, and the mixture is mixed to obtain a mixed slurry acrylic slurry.

[0094] Example 12

[0095] This embodiment provides a battery, which includes a battery housing coated with an insulating and thermally conductive coating, and a pole core, an electrolyte, and a structural member disposed inside the battery housing without being wrapped with a mylar film. The thickness of the insulating and thermally conductive coating is 0.1 mm, and its preparation method is basically the same as that of Example 1, except that: in step (1), 0.03 parts by mass of high-thermal-conductivity aluminum nitride particles are added to 1 part by mass of the insulating and thermally conductive adhesive material acrylic emulsion, and the mixture is mixed to obtain a mixed slurry acrylic slurry.

[0096] Example 13

[0097] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1, except that: in step (1), 0.04 parts by mass of high heat-conductivity aluminum nitride particles are added to 1 part by mass of the insulating and heat-conducting adhesive material acrylic emulsion to obtain a mixed slurry acrylic slurry.

[0098] Embodiment 14

[0099] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm, and its preparation method is basically the same as that of Embodiment 1, except that: in step (1), 0.05 parts by mass of high heat-conductivity aluminum nitride particles are added to 1 part by mass of the insulating and heat-conducting adhesive material acrylic emulsion to obtain a mixed slurry acrylic slurry.

[0100] Comparative Example 1

[0101] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm. Except that boron nitride particles are not added to the insulating and heat-conducting adhesive material, other preparation steps are the same as those of Embodiment 1.

[0102] Comparative Example 2

[0103] This embodiment provides a battery, which includes a battery case coated with an insulating and heat-conducting coating, and a pole core, an electrolyte, and a structural member disposed inside the battery case without being wrapped with a mylar film. The thickness of the insulating and heat-conducting coating is 0.1 mm. Except that aluminum nitride particles are not added to the insulating and heat-conducting adhesive material, other preparation steps are the same as those of Embodiment 8.

[0104] Test Example

[0105] The batteries of the above embodiments and comparative examples are tested for the following performances:

[0106] 1. Battery fast charge cycle test: Adopt a stepped fast charging mode, with an average charging current of 4C, an average discharging current of 1C, and a voltage range of 2.0V - 3.75V. After 800 cycles, calculate the capacity retention rate of the battery after 800 cycles and detect the temperature at the middle position of the large surface of the battery. The test results are shown in Table 2.

[0107] 2. Battery thermal runaway test: Assemble the batteries described in the above embodiments or comparative examples into modules, heat a designated single cell until thermal runaway occurs, and observe whether the cell explodes. The test results are shown in Table 2.

[0108] Table 2 Performance test results

[0109]

[0110] The following conclusions can be analyzed from Table 2:

[0111] (1) Compared with Comparative Examples 1-2, for the batteries provided in Embodiments 1-14, which include the battery case provided in the present application, the electrode core without wrapped mylar film, the electrolyte, and the structural parts disposed inside the battery case, the battery temperature rise can be effectively reduced, the decomposition of the electrolyte caused by high temperature can be avoided, and the cycle performance can be improved. At the same time, due to timely heat dissipation, the serious gas generation caused by too high temperature can be effectively avoided, the explosion of the shell can be avoided, and the safety performance can be improved.

[0112] (2) By adding different contents of highly thermally conductive materials boron nitride or aluminum nitride, the temperature rise during the fast charging process of the battery can be reduced. The more the addition amount, the greater the reduction of the temperature rise. However, the appropriate addition dose needs to be controlled at the same time. Too high a content of the highly thermally conductive material may affect the adhesiveness and flexibility of the insulating and thermally conductive coating, and may even cause cracking or peeling of the insulating and thermally conductive coating.

[0113] In summary, by adding different contents of boron nitride or aluminum nitride particles to the insulating and thermally conductive adhesive material, batteries with different heat dissipation effects can be prepared to meet different fast charging application requirements.

[0114] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery housing, characterized in that: include: A shell and an insulating thermal conductive coating coated inside the shell, wherein the insulating thermal conductive coating is composed of an insulating thermal conductive adhesive material and a high thermal conductivity material.

2. The battery housing according to claim 1, characterized in that: The thickness of the insulating thermal conductive coating is 0.05 mm-0.3 mm.

3. The battery housing according to claim 1 or 2, characterized in that: The insulating thermal conductive adhesive material is acrylic emulsion.

4. The battery case according to claim 3, characterized in that: The high thermal conductivity material is aluminum nitride particles or boron nitride particles.

5. The battery casing according to claim 4, characterized in that: In the insulating thermal conductive coating, the ratio of the aluminum nitride particles to the acrylic emulsion is 0.1%-5%; or, the ratio of the boron nitride particles to the acrylic emulsion is 0.1%-5%.

6. A pole core, characterized in that: The pole core is a positive pole sheet, and the negative pole sheet and the separator are made by lamination or winding, and the outside of the pole core is not wrapped with a Mylar film.

7. A battery, characterized in that: include: The battery casing according to any one of claims 1 to 5, and the pole core, electrolyte and structural parts not wrapped with mylar film arranged inside the battery casing.

8. A method for preparing a battery casing, characterized in that: include: Adding a high thermal conductivity material to an insulating thermal conductive adhesive material to obtain a mixed slurry; The mixed slurry is sprayed inside the shell to obtain the battery shell according to any one of claims 1 to 5.

9. The method according to claim 8, characterized in that The insulating thermally conductive adhesive material is an acrylic emulsion, and a high thermal conductivity material is added to the insulating thermally conductive adhesive material to obtain a mixed slurry, including: A high thermal conductivity material is added to the acrylic emulsion to obtain acrylic slurry as the mixed slurry.

10. The method according to claim 9, characterized in that The high thermal conductivity material is aluminum nitride particles or boron nitride particles, and the high thermal conductivity material is added to the acrylic emulsion, including: Boron nitride particles or aluminum nitride particles are added to the acrylic emulsion, wherein the ratio of the aluminum nitride particles to the acrylic emulsion is 0.1%-5%; or, the ratio of the boron nitride particles to the acrylic emulsion is 0.1%-5%.

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