Heat insulation pad and preparation method therefor

Abstract

A heat insulation pad and a preparation method therefor. The heat insulation pad comprises a heat insulation core material, wherein the heat insulation core material comprises at least two layers of heat insulation felt, which are connected by means of an adhesive layer; and the adhesive layer contains a water-based adhesive and is provided with a gas escape channel. The heat insulation pad has a relatively large thickness, a flat surface, a small thickness tolerance and excellent heat insulation performance.

Description

Thermal insulation pad and preparation method thereof Technical Field

[0001] The present disclosure relates to the technical field of aerogels, and in particular to a thermal insulation pad and a preparation method thereof. Background Art

[0002] When batteries are in use, they generate a certain amount of heat due to electrochemical changes and material transfer within the battery cells. If this heat cannot be fully dissipated into the environment, it will cause heat accumulation within the battery cells. Once the heat accumulation causes the internal temperature of the battery cells to become too high, side reactions will occur within the battery cells, affecting the battery's cycle life. In severe cases, thermal runaway may occur and spread to adjacent battery cells, causing a chain reaction. Because aerogel has excellent thermal insulation properties and is elastic and deformable, thermal pads made of thermal insulation felt are used in battery thermal management. Specifically, they are often used as thermal insulation buffers between battery cells and between battery cells and top covers.

[0003] Among the existing insulation mats on the market, some aerogel mats can only be produced in thin products, and the single-layer thickness does not meet the requirements for battery thermal management insulation mats. Although some aerogel mats are thicker, these also have large thickness tolerances, poor surface flatness, poor internal structural uniformity, and uneven thermal insulation performance, which does not meet the requirements of battery thermal management insulation mats. Therefore, how to produce thicker and smoother insulation mats is an urgent problem that needs to be solved. Summary of the Invention

[0004] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and to provide a thermal insulation pad and a preparation method thereof. The method of the present invention can be used to prepare a thermal insulation pad with a large thickness and a smooth surface.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides an insulation pad, including an insulation core material, the insulation core material includes at least two layers of insulation felt, and the insulation felts are connected by an adhesive layer; the adhesive layer contains a water-based adhesive and is provided with a gas escape channel.

[0007] In some embodiments, based on the area of ​​the thermal insulation felt, the coverage of the water-based adhesive is 30%-70%; and / or,

[0008] The width of the gas escape channel is 8-70 mm; and / or,

[0009] In the adhesive layer, the gas escape channels are arranged at intervals along the width direction of the thermal insulation felt; and / or,

[0010] In the adhesive layer, the water-based adhesive is in the shape of at least one of strips, dots, and blocks;

[0011] Preferably, in the adhesive layer, when the water-based adhesive is in the shape of strips or blocks, the coating width is 8-30 mm.

[0012] In some embodiments, the thickness of the thermal insulation pad is greater than 1 mm; and / or,

[0013] The thickness tolerance of the thermal insulation pad is within ±0.25 mm, preferably within ±0.15 mm; and / or,

[0014] The thickness of each layer of thermal insulation felt is less than 0.9 mm, preferably 0.2 mm to 0.8 mm; and / or,

[0015] The thickness tolerance of each layer of thermal insulation felt is within ±0.1mm.

[0016] In some embodiments, the thermal insulation felt comprises original felt and / or composite felt;

[0017] Preferably, the raw felt is selected from at least one of pre-oxidized silk fiber felt, glass fiber felt and ceramic fiber felt;

[0018] Preferably, the composite felt comprises raw felt and functional materials, wherein the functional materials preferably include at least one of a heat insulating material, a light-shielding material, a buffer material and a structural member; and / or,

[0019] The water-based adhesive includes at least one of silica sol, aluminum sol, sodium polyacrylate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose and sodium alginate.

[0020] In some embodiments, the thermal insulation material comprises at least one of thermal insulation powder, aerogel, thermal insulation material, and fiber-reinforced aerogel composition; and / or,

[0021] The cushioning material includes foam and / or silica gel.

[0022] In some embodiments, the thermal insulation pad further comprises at least one of an encapsulation layer and a functional layer;

[0023] Preferably, the encapsulation material of the encapsulation layer comprises an encapsulation film material and / or an encapsulation coating;

[0024] Preferably, the functional layer includes at least one of a heat conducting layer, a heat absorbing layer, a heat reflecting layer and a buffer layer;

[0025] More preferably, the buffer layer includes foam and / or silica gel.

[0026] In some embodiments, the thermal insulation pad comprises at least three layers of thermal insulation felt, and two adjacent layers of thermal insulation felt are connected by an adhesive layer;

[0027] Preferably, the coating positions of the water-based adhesive on different adhesive layers are not exactly the same.

[0028] A second aspect of the present disclosure provides a method for preparing a thermal insulation pad, the method comprising:

[0029] (1) bonding at least two layers of thermal insulation felt using a water-based adhesive so that adjacent thermal insulation felts are connected to each other to obtain a bonded preform;

[0030] (2) drying the bonded preform to obtain a thermal insulation mat comprising thermal insulation felt connected by an adhesive layer;

[0031] A gas escape channel is provided in the adhesive layer.

[0032] In some embodiments, based on the area of ​​the thermal insulation felt, the coating rate of the water-based adhesive is 30%-70%; and / or,

[0033] The width of the gas escape channel is 8-70 mm; and / or,

[0034] In the adhesive layer, the gas escape channels are arranged at intervals along the width direction of the thermal insulation felt; and / or,

[0035] In the adhesive layer, the water-based adhesive is in the shape of at least one of strips, dots, and blocks;

[0036] Preferably, in the adhesive layer, when the water-based adhesive is in the shape of strips or blocks, the coating width is 8-30 mm.

[0037] In some embodiments, the thermal insulation felt comprises original felt and / or composite felt;

[0038] Preferably, the raw felt is selected from at least one of pre-oxidized silk fiber felt, glass fiber felt and ceramic fiber felt;

[0039] Preferably, the composite felt comprises raw felt and functional materials, wherein the functional materials preferably include at least one of a heat insulating material, a light shielding material, a buffer material and a structural member; and / or

[0040] The water-based adhesive includes at least one of silica sol, aluminum sol, sodium polyacrylate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose and sodium alginate.

[0041] In some embodiments, in step (2), the drying method is at least one of oven drying, drying tunnel drying, and microwave drying;

[0042] Preferably, the drying conditions include: a drying temperature of 60° C. to 200° C., and a drying time of 1 to 30 minutes.

[0043] In some embodiments, the oven drying conditions include: a temperature of 60-200° C., a drying time of 5-30 min; or,

[0044] The drying conditions in the drying tunnel include: drying temperature of 120-180°C, preferably 140-160°C, drying time of 1-15 minutes, preferably 2-10 minutes; or,

[0045] The conditions for microwave drying include: drying temperature of 70° C.-130° C., preferably 80-120° C., and drying time of 1-10 min, preferably 2-5 min.

[0046] In some embodiments, the method further comprises providing a functional layer on at least one side of the at least one layer of thermal insulation felt and / or outside the thermal insulation core material;

[0047] Preferably, the functional layer includes at least one of a heat conducting layer, a heat absorbing layer, a heat reflecting layer and a buffer layer;

[0048] More preferably, the buffer layer includes foam and / or silica gel.

[0049] In some embodiments, the method further comprises packaging the dried thermal insulation core material to obtain a thermal insulation mat;

[0050] Preferably, the material used for the encapsulation process comprises an encapsulation film material and / or an encapsulation coating;

[0051] Preferably, the encapsulating coating is a flame retardant coating.

[0052] The third aspect of the present invention provides the use of the thermal insulation pad described in the first aspect or the thermal insulation pad prepared by the method described in the second aspect as a thermal insulation component in the battery field.

[0053] The above technical solution adopted by the present disclosure has the following beneficial effects:

[0054] (1) The thermal insulation pad disclosed in the present invention is thicker and has a smaller thickness tolerance, and has better thermal insulation performance. In addition, the addition of adhesive in the thermal insulation pad improves the mechanical strength of the thermal insulation pad, making the thermal insulation pad less likely to deform, delaminate, and bulge, and can meet the application requirements of power battery thermal management.

[0055] (2) The method disclosed herein is simple to operate, is conducive to achieving continuous and standardized production, has relatively higher production efficiency, and relatively lower production costs.

[0056] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. Herein, unless otherwise specified, data ranges include endpoints. DETAILED DESCRIPTION

[0057] The technical solutions of the present disclosure will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present disclosure and should not be construed as limiting the scope of protection of the present disclosure. All technologies implemented based on the above content of the present disclosure are included within the scope of protection intended by the present disclosure.

[0058] It should be noted that the numerical expressions such as "first" and "second" in the present disclosure are only used to distinguish different substances or usage methods, and do not represent a difference in order.

[0059] Unless otherwise defined, all scientific and technical terms used in the present disclosure have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs.

[0060] During their research, the inventors of the present disclosure discovered that by stacking multiple layers of insulation felt with small tolerances and uniform thickness, and then applying adhesive to the insulation felt, a thicker insulation mat can be prepared. However, this is prone to problems with large thickness tolerances. Even if no problems occur when the insulation mat is obtained, the problem of increased thickness tolerances may occur during subsequent use. This is especially true when the insulation mat is obtained by stacking more than three layers of insulation felt. These problems are more likely to occur, and may also be accompanied by yellowing of the color. Through research, it was found that by leaving a gas escape channel in the adhesive layer when applying the adhesive, especially in combination with preferred drying conditions, an insulation mat with a larger thickness and small thickness tolerance can be produced, and the quality is stable during subsequent storage and use.

[0061] A first aspect of the present disclosure provides an insulation pad, comprising an insulation core material, wherein the insulation core material comprises at least two layers of insulation felt, and the insulation felts are connected by an adhesive layer; the adhesive layer contains a water-based adhesive and is provided with a gas escape channel.

[0062] The thermal insulation felt may be a conventional layered material having thermal insulation properties. In some embodiments, the thermal insulation felt includes original felt and / or composite felt.

[0063] In some embodiments, the raw felt is selected from at least one of pre-oxidized silk fiber felt, glass fiber felt, and ceramic fiber felt.

[0064] In some embodiments, the glass fiber mat is a needle-punched glass fiber mat and / or a wet-laid glass fiber mat.

[0065] The composite felt may have a single or multiple layer structure. A single-layer composite felt may be a product of a base felt blended with a material having a specific function. A multi-layer composite felt, i.e., a laminated structure, may include, in addition to the base felt and / or a material containing the base felt and the functional material, a functional layer, etc. Functional materials and functional layers are described below.

[0066] In some embodiments, the composite felt comprises a raw felt and a functional material. The functional material preferably includes at least one of a thermal insulation material, a light-shielding material, a cushioning material, and a structural component. The functional material can be added in the form of a powder. The structural component, for example, is a metal part that has a certain mechanical strength and can provide structural support.

[0067] In some embodiments, the thermal insulation material comprises at least one of thermal insulation powder, aerogel, thermal insulation material (such as rock wool, asbestos mesh, etc.), and fiber-reinforced aerogel composition. The fiber-reinforced aerogel composition can be a product formed by pressing fibers and thermal insulation material.

[0068] When the composite felt contains aerogel, the composite felt is an aerogel felt, for example, it can be at least one of pre-oxidized silk fiber aerogel felt, glass fiber aerogel felt and ceramic fiber aerogel felt.

[0069] In some embodiments, the thermal insulation powder includes micron thermal insulation powder and / or nano thermal insulation powder.

[0070] In some embodiments, the specific material of the micron thermal insulation powder is not limited and can be selected according to needs. For example, it can be at least one of micron fumed alumina powder, micron fumed silica powder, silica ash, white carbon black, diatomaceous earth, fly ash, micron alumina aerogel powder and micron silica aerogel powder.

[0071] In some embodiments, the particle size Dv50 of the micron thermal insulation powder is 1-100 μm.

[0072] In the present invention, Dv50 refers to the particle size corresponding to when the cumulative volume particle size distribution percentage of a sample reaches 50%, which can be obtained by testing with a particle size analyzer.

[0073] In some embodiments, the specific material of the nano thermal insulation powder is not limited and can be selected according to needs. For example, it can be at least one of nano silica powder, nano alumina powder, nano zirconium oxide powder, nano titanium oxide powder, nano iron oxide powder, nano zirconium oxide aerogel powder, nano silica aerogel powder and nano alumina aerogel powder.

[0074] In some embodiments, the particle size Dv50 of the nano thermal insulation powder is 5nm-100nm.

[0075] The thermal insulation powder can be mixed with an adhesive and an optional light-shielding material so that the thermal insulation powder is embedded in the pores of the fiber mat. The adhesive facilitates the connection between the thermal insulation powder and the fibers in the fiber mat.

[0076] In some embodiments, the light-shielding material comprises a light-shielding agent.

[0077] In some embodiments, the choice of the sunscreen is not particularly limited and can be selected according to actual needs. For example, the sunscreen can be at least one of silicon carbide, titanium dioxide, zirconium oxide, zinc oxide, potassium hexatitanate whiskers, or silicon carbide whiskers.

[0078] In some embodiments, the particle size Dv50 of the sunscreen is 2 μm-10 μm.

[0079] In some embodiments, the opacifier is potassium hexatitanate whiskers and / or silicon carbide whiskers.

[0080] In some embodiments, the potassium hexaferrite whiskers have an aspect ratio of 5-25 and a diameter of 1.5-5 μm.

[0081] In some embodiments, the silicon carbide whiskers have an aspect ratio of 20-30 and a diameter of 0.2-2.5 μm.

[0082] In the present invention, the diameter of the whiskers can be measured by microscopic observation.

[0083] The cushioning material can provide the composite felt with better resilience and impact resistance. In some embodiments, the cushioning material includes foam and / or silicone. The foam may include but is not limited to PU foam, EPE, CR foam, EVA foam, PE foam, PP foam, PVC foam, polyester foam, polyurethane foam, melamine foam, etc.

[0084] It should be understood that those skilled in the art may also add additives to achieve desired functions as needed, which are not listed here one by one. Unless otherwise specified, the materials used may be conventional materials in the art.

[0085] In some embodiments, the thickness of each layer of thermal insulation felt is less than 0.9 mm, preferably 0.2 mm to 0.8 mm; for example, it can be 0.20 mm, 0.25 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm and 0.8 mm, as well as any value in the range formed by any two of these point values.

[0086] In some embodiments, the thickness tolerance of each layer of thermal insulation felt is within ±0.1 mm.

[0087] In some embodiments, the thermal insulation felt is a sheet or a roll.

[0088] In some embodiments, the insulation felt is a roll.

[0089] In some embodiments, the thickness of the thermal insulation pad is greater than 1 mm, for example, it can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm and 10 mm.

[0090] In some embodiments, the thickness tolerance of the thermal insulation pad is within ±0.25 mm, preferably within ±0.15 mm.

[0091] In this disclosure, the type of water-based adhesive is not specifically limited and can be selected based on actual needs. For example, it can be at least one of silica sol, aluminum sol, sodium polyacrylate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium alginate. For a given thickness of thermal insulation mat, the strength of multiple layers of thermal insulation felt after coating with adhesive is greater than that of a single layer of aerogel felt. Therefore, the thermal insulation mat is less prone to deformation and can meet the requirements of power battery thermal management applications.

[0092] In some embodiments, in the adhesive layer, the water-based adhesive is in the shape of at least one of strips, dots, and blocks.

[0093] In some embodiments, when the water-based adhesive in the adhesive layer is in the form of a strip or block, the coating width is 8-30 mm, for example, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm. It is understood that the width refers to the shorter side of the strip or block.

[0094] In some embodiments, based on the area of ​​the thermal insulation felt, the coverage of the water-based adhesive is 30%-70%; for example, it can be 30%, 40%, 50%, 60% and 70%.

[0095] In the present disclosure, the coverage of the water-based adhesive is the ratio of the adhesive coating area to the insulation felt area.

[0096] In the present disclosure, the gas escape channel refers to a channel provided in the adhesive layer through which gas can freely pass. The provision of the gas escape channel makes the thermal insulation pad more flat and the thickness more uniform.

[0097] In some embodiments, the width of the gas escape channel is 8-70 mm; for example, it can be 8 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, and 70 mm. The width of the gas escape channel refers to the width of the channel for gas escape.

[0098] In some embodiments, the gas escape channels in the adhesive layer are spaced apart along the width of the insulation felt. This allows moisture generated by drying the adhesive at different locations to be discharged through the spaced-apart channels, thereby producing an insulation mat with more uniform thickness, improved flatness, and better bonding. In this technical solution, the insulation core material obtained after pasting and drying must be cut to the target size as required. If the gas escape channels are too wide, individual insulation felts will not be coated with adhesive after cutting, and the product cannot be guaranteed to remain in contact after cutting. Therefore, the airflow channels cannot be set too wide.

[0099] In some embodiments, the thermal insulation mat comprises at least three layers of thermal insulation felt, and two adjacent layers of thermal insulation felt are connected by an adhesive layer. The thickness of the thermal insulation felt can be the same or different.

[0100] In some embodiments, the water-based adhesive can be applied at the same or different locations on different adhesive layers. That is, the width of the gas escape channel can be the same or different on different adhesive layers. The application locations of the water-based adhesive can be staggered in different adhesive layers, thereby helping to achieve uniform thickness in the final thermal insulation mat.

[0101] In some embodiments, the coating positions of the water-based adhesive on different adhesive layers are not exactly the same.

[0102] In some embodiments, the thermal insulation pad includes at least one of an encapsulation layer and a functional layer.

[0103] In some embodiments, the thermal insulation pad includes an encapsulation layer, wherein the encapsulation layer is used to encapsulate the thermal insulation core material. The encapsulation material of the encapsulation layer is not specifically limited and can be selected according to actual needs.

[0104] In some embodiments, the encapsulation material of the encapsulation layer includes an encapsulation film material and / or an encapsulation coating.

[0105] In some embodiments, the packaging film material may include at least one of a PE film, a PET film, a PC film, a PI film, and a PP film.

[0106] In some embodiments, the encapsulating coating is a flame retardant coating.

[0107] In some embodiments, the flame retardant coating may include at least one of a polyurethane coating, an epoxy coating, a silicone coating, a modified silicone coating, and an EVA coating.

[0108] In some embodiments, the type of the functional layer is not specifically limited and can be selected according to actual needs, such as at least one of a heat conductive layer, a heat absorbing layer, a heat reflecting layer, and a buffer layer.

[0109] In some embodiments, the heat conductive layer may be a layer made of materials such as graphite.

[0110] In some embodiments, the heat absorption layer may include a phase change material (e.g., at least one of paraffin wax, inorganic hydrated salt, and hydrogel). The heat absorption layer may encapsulate the insulating core material by impregnating the phase change material into the insulating core material or wrapping the insulating core material.

[0111] In some embodiments, the heat reflective layer includes gold foil, silver foil, nickel foil, aluminum foil, copper foil or metal-plated polyester or polyimide film. The heat reflective layer can be arranged on one side or both sides of each layer of insulation felt or wrap the insulation core material to reflect thermal radiation.

[0112] The material of the buffer layer is not subject to specific restrictions and can be selected according to actual needs, such as foam and / or silicone. The foam can exist in the form of a foam layer and can be arranged on one side or both sides of each layer of insulation felt or wrap the insulation core material. When the buffer layer is silicone, it can be a silicone frame or a silicone strip. The silicone frame can be arranged on the outer edge of the insulation core material, surrounding the insulation core material on all sides, so that the insulation core material is embedded in the silicone frame; the silicone strip can be arranged on one side or both sides of the insulation core material, and arranged on the two corresponding sides of one side of the insulation core material, or the silicone strip can also be arranged on the outer edge of the insulation core material and arranged at the opposite ends of the insulation core material.

[0113] In some embodiments, the thermal insulation pad includes a packaging layer and a functional layer. The functional layer is arranged on one side or both sides of each layer of thermal insulation felt, and the packaging layer wraps the functional layer and the thermal insulation core material.

[0114] In some embodiments, the thermal insulation pad includes a packaging layer and a functional layer, the functional layer is disposed on one side or both sides of the thermal insulation core material, and the packaging layer wraps the functional layer and the thermal insulation core material.

[0115] In some embodiments, the thermal insulation pad includes a packaging layer and a functional layer, the functional layer directly wraps the thermal insulation core material, and the packaging layer wraps the outside of the functional layer.

[0116] A second aspect of the present disclosure provides a method for preparing a thermal insulation mat, the method comprising:

[0117] (1) bonding at least two layers of thermal insulation felt using a water-based adhesive so that adjacent thermal insulation felts are connected to each other to obtain a bonded preform;

[0118] (2) drying the bonded preform to obtain a thermal insulation mat comprising thermal insulation felt connected by an adhesive layer;

[0119] A gas escape channel is provided in the adhesive layer.

[0120] In some embodiments, the thermal insulation pad comprises two layers of thermal insulation felt, and the specific preparation method includes: coating an adhesive on the upper surface or lower surface of the first aerosol felt, superimposing the second thermal insulation felt on the surface coated with the adhesive, drying after superposition, and cutting into sheets to obtain the first thermal insulation pad.

[0121] In some embodiments, the thermal insulation pad comprises three layers of thermal insulation felt, and the specific preparation method includes: coating the upper and lower surfaces of the first thermal insulation felt with adhesive; superimposing the second thermal insulation felt and the third thermal insulation felt on the upper and lower surfaces of the first thermal insulation felt coated with adhesive, respectively; and drying and cutting the thermal insulation pad into sheets after superposition.

[0122] In some embodiments, the thermal insulation pad comprises three layers of thermal insulation felt, and the specific preparation method includes: coating an adhesive on one surface of the first thermal insulation felt; coating an adhesive on one surface of the second thermal insulation felt; stacking the first thermal insulation felt, the second thermal insulation felt, and the third thermal insulation felt so that adhesive is coated between each two thermal insulation felts; and drying and cutting the stacked thermal insulation pad into sheets.

[0123] In some embodiments, the thermal insulation pad can be made by unwinding the thermal insulation felt, applying glue and stacking more than four layers in the above manner according to the actual thickness requirements. After stacking and drying, the required thermal insulation pad is obtained.

[0124] In some embodiments, the thermal insulation felt is a sheet or a coil. When the thermal insulation felt is a coil, the thermal insulation mat is prepared by unwinding the coil, applying glue on the thermal insulation felt after unwinding, stacking and drying, and then cutting into sheets.

[0125] In addition, in some embodiments, the multi-layer thermal insulation felt is a sheet material, and the specific operation method is to apply glue to the sheet-like thermal insulation felt, stack and dry them to obtain a thermal insulation pad.

[0126] Regarding the structure and properties of the thermal insulation felt and the adhesive layer, please refer to the first aspect and will not be repeated here.

[0127] The difficulty in stacking after gluing is that the insulation felt itself has good thermal insulation properties, making it difficult to dry the glue. Therefore, the degree of drying of the insulation felt will affect the delamination of the insulation mat. When there are many layers of insulation felt, it is difficult to dry, and the dried product is prone to bulging, which will further cause the insulation felt to delaminate. After packaging is completed, for insulation mats with residual moisture, that is, insulation mats that are not completely dry, when the external ambient temperature increases or the pressure drops, the gas expands and bulges. Therefore, drying conditions such as drying temperature, drying time, and the corresponding number of insulation felt layers and the amount of glue applied all have a significant impact on the final insulation mat's lack of delamination and bulging.

[0128] In some embodiments, in step (2), the drying method is at least one of oven drying, drying tunnel (such as tunnel oven) drying and microwave drying, which is conducive to producing a thermal insulation pad with better uniformity, and the produced thermal insulation pad is not easy to delaminate.

[0129] In some embodiments, the drying conditions include: a drying temperature of 60° C. to 200° C., and a drying time of 1 to 30 minutes.

[0130] In some embodiments, the oven drying conditions include: a temperature of 60-200° C. and a drying time of 5-30 min.

[0131] In some embodiments, the drying method is drying in a drying tunnel. For example, the bonded preform can be placed on a moving element, and the moving element conveys the product into the drying tunnel for drying. The drying conditions include: a drying temperature of 120°C-180°C, preferably 140-160°C, and a drying time of 1-15 minutes, preferably 2-10 minutes.

[0132] In some embodiments, the drying method is microwave drying, and the drying conditions include: drying temperature of 70° C.-130° C., preferably 80-120° C., and drying time of 1-10 min, preferably 2-5 min.

[0133] In some embodiments, the method for preparing the thermal insulation mat further comprises applying pressure to the thermal insulation core material using a pressing roller before or during drying to obtain a flat surface.

[0134] In some embodiments, when the thermal insulation core material is a sheet material, pressure is applied thereto by at least two pressing rollers, and the distance between the two pressing rollers is less than the length of the sheet material along the feeding direction.

[0135] In some embodiments, the method further comprises providing a functional layer on at least one side of at least one layer of insulation felt and / or outside the insulation core material. The functional layer can be provided on one or both sides of each layer of insulation felt, one or both sides of the insulation core material, or directly wrapping the insulation core material.

[0136] In some embodiments, the method for preparing the thermal insulation pad further includes packaging the dried thermal insulation core material to obtain the thermal insulation pad.

[0137] In some embodiments, the material used for the encapsulation process includes an encapsulation film and / or an encapsulation coating.

[0138] For the description of the functional layer and the materials used for packaging processing, please refer to the first aspect and will not be repeated here.

[0139] The third aspect of the present invention provides the use of the thermal insulation pad described in the first aspect or the thermal insulation pad prepared by the method described in the second aspect as a thermal insulation component in the battery field.

[0140] Those skilled in the art can use the thermal insulation pad as needed to ensure the thermal safety of the battery or perform thermal management of the battery. For example, the thermal insulation pad can be used in the preparation of energy storage cabinets or battery packs for new energy vehicles.

[0141] The present invention further provides a battery pack comprising a plurality of battery cells arranged in an array, wherein the thermal insulation pad as described above is disposed between at least two adjacent battery cells.

[0142] The present invention also provides an electric device comprising the battery pack described above.

[0143] The following will be combined with the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present disclosure.

[0144] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0145] The present disclosure is described in detail below with reference to specific embodiments, which are intended to help understand rather than limit the present disclosure.

[0146] Example 1 and Comparative Example 1

[0147] A wet-process glass fiber aerogel felt with a thickness of 0.8 mm (thickness tolerance within ±0.1 mm) is unwound, and then an adhesive is coated on its upper surface at preset intervals along the width direction of the thermal insulation pad through a coating device. The wet-process glass fiber aerogel felt is then stacked in sequence, and then coated with adhesive. After the top layer of aerogel felt is covered, it is sent into a tunnel furnace for drying or dried using 110°C hot air combined with microwave drying. It is then flattened by a pressing roller and cut into sheets to obtain a thermal insulation core material. The thermal insulation core material is then encapsulated by a PET encapsulation film to obtain a thermal insulation pad.

[0148] The different aerogel felt layer numbers, gluing methods, single layer gluing amounts, and drying conditions are shown in Table 1 The results of the stratification are shown in Table 1 .

[0149] In Example 1, the thickness tolerance of the thermal insulation pad obtained by stripe coating is within ±0.15mm, and the thickness tolerance of the thermal insulation pad obtained by full coating in Comparative Example 1 is about ±0.3mm. This thickness tolerance does not take bulging into account.

[0150] Table 1

[0151] From the results in Table 1, it can be seen that the thermal insulation pad prepared by stacking multiple thin layers of aerogel felt and gluing them with an adhesive has good uniformity and is not easy to delaminate.

[0152] The thermal conductivity and shear strength of the insulation core materials of Examples 1-1 to 1-5 were measured. A single-piece felt made of the same material and having a thickness consistent with the total thickness of the insulation mat was also measured using a standardized method for thermal conductivity and shear strength. The results are shown in Table 2. The thermal conductivity test method was the heat flow method; the shear strength test method was based on GB / T 1450.2-2005: Test method for punching shear strength of fiber-reinforced plastics.

[0153] Table 2

[0154] It can be seen from the above data that compared with the integral felt, the thermal insulation core material disclosed in the present invention has better thermal insulation performance and significantly higher shear strength.

[0155] Example 2 group

[0156] The operation was carried out according to the method described in Example 1-2, except that the composition of the thermal insulation core material was different.

[0157] Example 2-1: Wet-laid glass fiber raw mat is used instead of wet-laid glass fiber aerogel mat, and its thickness and number of layers remain unchanged.

[0158] Example 2-2: A 0.8 mm thick polyurethane foam layer was used to replace the wet-laid glass fiber aerogel mat in the middle of Example 1-2, with other conditions remaining unchanged. That is, the structure of the thermal insulation core material was wet-laid glass fiber aerogel mat - foam layer - aerogel mat.

[0159] The thermal conductivity and resilience of the prepared thermal insulation core material were tested. The test method for the resilience performance refers to GBT 34336-2017 Nanoporous Aerogel Composite Insulation Products. The test results are shown in Table 3.

[0160] Table 3

[0161] Example 3 group

[0162] The operation was carried out in the manner of Example 1-1, except that the number of aerogel felt layers and the coverage of the water-based adhesive based on the area of ​​the insulation felt were different (30%, 40%, 45%, 50%, 60%, and 70%, respectively). The peel strength of the prepared insulation core material was tested, and the results are shown in Table 4.

[0163] Peel strength test method: Test 180° peeling. Take the sample to be tested and cut it into 5 250mm*25+0.5mm specimens. Place them in the testing room (temperature 25±3℃ and humidity 50+5% RH environment) for more than 2 hours. Use a universal testing machine to continuously peel at a speed of 300±10mm / min. The effective peeling length of the adhesive surface is about 250mm, and the peel strength is tested.

[0164] When the coating rate is greater than or equal to 50%, the thermal insulation core material will be destroyed when being torn, and the force at this time is used as the peeling force.

[0165] Table 4

[0166] Example 4 Group

[0167] The procedure of Example 1-1 was followed, except that the number of aerogel felt layers (2, 3, 4, and 5, respectively) and the width of the escape channel (8 mm, 16 mm, 24 mm, 32 mm, 40 mm, 48 mm, 56 mm, and 64 mm, respectively) were varied. The coating rate was maintained at 50%, and the peel strength of the prepared thermal insulation core materials was tested. The results are shown in Table 5. The probability of bulging in every 100 samples was recorded, as shown in Table 6. The occurrence of bulging means that a significant bulge can be seen on the surface of the local area when observed with the naked eye, and gas can be discharged by pressing. The bulging area indicates that the adhesion was not successful.

[0168] Table 5

[0169] Table 6

[0170] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present disclosure is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0171] The above describes the embodiments of the present disclosure. However, the present disclosure is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A heat insulation pad, characterized in that, It includes a heat-insulating core material, and the heat-insulating core material includes at least two layers of heat-insulating felts, and the heat-insulating felts are connected by an adhesive layer; The adhesive layer contains an aqueous adhesive and is provided with gas escape channels.

2. The heat insulation pad according to claim 1, characterized in that, Based on the area of the heat-insulating felt, the coverage rate of the aqueous adhesive is 30%-70%; and / or, The width of the gas escape channel is 8-70 mm; and / or, In the adhesive layer, the gas escape channels are arranged at intervals along the width direction of the heat-insulating felt; and / or, In the adhesive layer, the shape of the aqueous adhesive is at least one of strip shape, dot shape and block shape; Preferably, when the shape of the aqueous adhesive in the adhesive layer is strip shape or block shape, the coating width is 8-30 mm.

3. The heat insulation pad according to claim 1 or 2, characterized in that, The thickness of the heat-insulating pad is more than 1 mm; and / or, The thickness tolerance of the heat-insulating pad is within ±0.25 mm, preferably within ±0.15 mm; and / or, The thickness of each layer of heat-insulating felt is below 0.9 mm, preferably 0.2 mm-0.8 mm; and / or, The thickness tolerance of each layer of heat-insulating felt is within ±0.1 mm.

4. The heat insulation pad according to any one of claims 1-3, characterized in that, The heat-insulating felt includes a virgin felt and / or a composite felt; Preferably, the virgin felt is selected from at least one of a pre-oxidized fiber felt, a glass fiber felt and a ceramic fiber felt; Preferably, the composite felt contains a virgin felt and a functional material, and the functional material preferably includes at least one of a heat-insulating material, a light-shielding material, a buffer material and a structural member; and / or, The aqueous adhesive includes at least one of silica sol, alumina sol, sodium polyacrylate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose and sodium alginate.

5. The heat insulation pad according to claim 4, characterized in that, The heat-insulating material includes at least one of heat-insulating powder, aerogel, heat-insulating material and fiber-reinforced aerogel composition; and / or, The buffer material includes foam and / or silica gel.

6. The heat insulation pad according to any one of claims 1-5, characterized in that, The heat-insulating pad further includes at least one of a packaging layer and a functional layer; Preferably, the packaging material of the packaging layer includes a packaging film material and / or a packaging coating; Preferably, the functional layer includes at least one of a heat-conducting layer, a heat-absorbing layer, a heat-reflecting layer and a buffer layer; More preferably, the buffer layer includes foam and / or silica gel.

7. The heat insulation pad according to any one of claims 1-6, characterized in that The heat-insulating pad includes at least three layers of heat-insulating felts, and adjacent two layers of heat-insulating felts are connected by an adhesive layer; Preferably, on different adhesive layers, the coating positions of the aqueous adhesive are not completely the same.

8. A method for preparing a heat insulation pad, characterized in that, The method includes: (1) Using an aqueous adhesive to bond at least two layers of heat-insulating felts so that adjacent heat-insulating felts are connected to each other to obtain a bonded preform; (2) Drying the bonded preform to obtain a heat-insulating pad containing heat-insulating felts connected by an adhesive layer; Gas escape channels are provided in the adhesive layer.

9. The method according to claim 8, wherein Based on the area of the heat-insulating felt, the coating rate of the aqueous adhesive is 30%-70%; and / or, The width of the gas escape channel is 8-70 mm; and / or, In the adhesive layer, the gas escape channels are arranged at intervals along the width direction of the heat-insulating felt; and / or, In the adhesive layer, the shape of the aqueous adhesive is at least one of strip shape, dot shape and block shape; Preferably, when the shape of the aqueous adhesive in the adhesive layer is strip-shaped or block-shaped, the coating width is 8 - 30 mm.

10. The method according to claim 8 or 9, characterized in that, The heat insulation felt includes a raw felt and / or a composite felt; Preferably, the raw felt is selected from at least one of a pre-oxidized fiber felt, a glass fiber felt, and a ceramic fiber felt; Preferably, the composite felt includes a raw felt and a functional material, and the functional material preferably includes at least one of a heat insulation material, a light shielding material, a buffer material, and a structural member; and / or The aqueous adhesive includes at least one of silica sol, aluminum sol, sodium polyacrylate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium alginate.

11. The method according to any one of claims 8-10, characterized in that, In step (2), the drying method is at least one of oven drying, tunnel drying, and microwave drying; Preferably, the drying conditions include: the drying temperature is 60°C - 200°C, and the drying time is 1 - 30 min.

12. The method according to claim 11, wherein The conditions for oven drying include: the temperature is 60 - 200°C, and the drying time is 5 - 30 min; or, The conditions for tunnel drying include: the drying temperature is 120°C - 180°C, preferably 140 - 160°C, and the drying time is 1 - 15 min, preferably 2 - 10 min; or, The conditions for microwave drying include: the drying temperature is 70°C - 130°C, preferably 80 - 120°C, and the drying time is 1 - 10 min, preferably 2 - 5 min.

13. The method according to any one of claims 8-12, characterized in that, The method further includes providing a functional layer on at least one side of at least one layer of heat insulation felt and / or outside the heat insulation core material; Preferably, the functional layer includes at least one of a heat conduction layer, a heat absorption layer, a heat reflection layer, and a buffer layer; More preferably, the buffer layer includes foam and / or silica gel.

14. The method according to any one of claims 8 - 13, characterized in that, The method further includes performing a packaging treatment on the heat insulation core material obtained by drying to obtain a heat insulation pad; Preferably, the material for the packaging treatment includes a packaging film material and / or a packaging coating; Preferably, the packaging coating is a flame retardant coating.

15. Use of the heat insulation pad according to any one of claims 1 - 7 or the heat insulation pad prepared by the method according to any one of claims 8 - 14 as a heat insulation member in the battery field.

Images