CN117096507A

CN117096507A - Heat insulation buffer sheet for battery unit cells, preparation method thereof and hot pressing die

Info

Publication number: CN117096507A
Application number: CN202210522791.9A
Authority: CN
Inventors: 邵琦
Original assignee: Dupont China R & D Management Co ltd
Current assignee: Dupont China R & D Management Co ltd
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2023-11-21

Abstract

The present disclosure provides a thermal insulation buffer sheet for use between battery cells, the thermal insulation buffer sheet comprising an outer package and an inner layer located in the outer package; the outer package has a top sheet, a bottom sheet, a left side sheet, a right side sheet, and front and rear sealing ports, which are integrally folded via rectangular sheets, and has a rectangular cross section; wherein the top sheet is formed by overlapping a left part and a right part; the inner layer comprises an aerogel layer; the heat insulation buffer sheet further comprises foam layers which serve as inner layers and are alternately overlapped with the aerogel layers to form a sandwich structure; and/or the foam layer is laminated outside the top sheet and/or the bottom sheet. The disclosure also provides a preparation method of the heat insulation buffer sheet and a hot pressing die.

Description

Heat insulation buffer sheet for battery unit cells, preparation method thereof and hot pressing die

Technical Field

The present disclosure relates to a thermal insulation buffer sheet used as a battery (batteries) inter-cell (cell-to-cell), a method of manufacturing the same, and a hot press mold.

Background

A battery structure having a plurality of unit cells (multi-cells) has battery unit cells arranged in parallel or in series, and is generally called a battery module (battery module) and a battery pack (battery pack). In these multi-cell battery pack structures, thermal energy from abnormal thermal problems (e.g., failure or malfunction in one cell) may be transferred to adjacent cells. If the thermal problem is severe enough, it may spread from one or more cells to adjacent cells and result in a thermal runaway condition that can affect all cells in the battery block or pack in succession, resulting in an even more severe fire. In addition, particularly for lithium ion batteries, the battery inevitably undergoes severe expansion and contraction during charge/discharge cycles, which deteriorates electrochemical performance, reliability and safety of the battery.

Therefore, an insulating buffer is required to separate the battery cells, prevent overheating and hot spots (hot spots) in one cell, so as not to cause the entire battery pack to evolve into a thermal runaway (thermal runaway) state that may cause a fire or explosion, and withstand severe volume changes during charge/discharge cycles. Thus, there is a need for an insulating cushion that is sufficiently thermally and dimensionally stable in a flame and that is sufficiently resilient.

However, some of the suggested insulating materials have properties that are not desirable to battery manufacturers. Some insulation materials made of inorganic materials have a high tendency to shed inorganic particles, which is undesirable because they create dust and adhesion problems. Some elastomeric materials have poor thermal insulation and low high temperature resistance. It is difficult to balance thermal insulation against resilience because conventional cushioning pads typically have a significant reduction in thermal insulation performance, e.g., at least 40% or 50%.

What is needed is a structure that provides a good balance between thermal insulation and elasticity, does not shrink drastically when exposed to direct flame or heat, accommodates shrinkage and expansion caused by battery charge-discharge cycles, and does not have undesirable properties of the battery manufacturer, such as shed inorganic particles.

In addition, in the conventional assembly method of the multi-layer heat insulation buffer material, each buffer layer and each heat insulation layer need to be placed respectively, the operation times are large, the assembly efficiency is low, and the assembly faults are easily caused due to dislocation among the layers. Accordingly, there is also a need to provide a method of preparing a multi-layered thermal insulation buffer material that improves assembly efficiency, avoids assembly failure.

Disclosure of Invention

The present disclosure provides a thermal insulation buffer sheet for use between battery cells, the thermal insulation buffer sheet comprising an outer package and an inner layer located in the outer package,

the outer package has a top sheet, a bottom sheet, a left side sheet, a right side sheet, and front and rear sealing ports, which are integrally folded via rectangular sheets, and has a rectangular cross section; wherein the top sheet is formed by overlapping a left part and a right part,

the inner layer comprises an aerogel layer,

the heat insulation buffer sheet further comprises foam layers which serve as inner layers and are alternately overlapped with the aerogel layers to form a sandwich structure; and/or the foam layer is laminated outside the top sheet and/or the bottom sheet.

The insulating buffer sheet according to the present disclosure achieves a good balance between insulation and elasticity.

The present disclosure also relates to a method of preparing an insulating buffer sheet comprising the steps of:

a) Folding a rectangular sheet into a shape with a top sheet, a bottom sheet, a left side sheet, a right side sheet and front and rear openings, wherein the top sheet is formed by overlapping left and right parts;

b) Combining the lap joint parts of the left part and the right part of the top sheet to form a hollow outer package with a rectangular cross section;

c) Sealing an opening of the outer package;

d) Placing an inner layer in the hollow portion of the outer package from the other opening of the outer package; and

e) Sealing the other opening of the outer package.

In a conventional manufacturing method, an inner layer is sandwiched between two sheets serving as an outer layer and heat-sealed around the periphery of the sheets. For the structure that the inner layer is a multi-layer sheet, the layer-to-layer movement brought in the hot pressing process can cause that the traditional preparation method can not effectively seal the inner layer material, thereby causing the risk of powder leakage of the inner aerogel layer.

In contrast, in the production method according to the present disclosure, a rectangular sheet is integrally folded to form an exterior package, and such exterior package has a fixing effect on an inner layer material due to having a crease.

Moreover, after the inner layer material is placed in the outer package, if the outer package is sealed by hot pressing, only one opening of the outer package is hot pressed, so that the inner layer material is not damaged, and the phenomenon that powder is removed due to the damage of the inner layer material and the adhesive strength of the outer seal is reduced is avoided.

In addition, the preparation method according to the present disclosure is easy to operate, and the structural integrity, stability, heat insulating performance, and elasticity of the heat insulating buffer sheet are significantly improved.

If a plurality of inner layers are taken as a whole and put into the outer package at one time, the stiffness of the inner layer material can be increased, and the assembly is convenient. In addition, a plurality of inner layers are not required to be sequentially arranged in the outer package, so that the operation times are reduced, and assembly faults caused by dislocation of the inner layers when the inner layers are separately arranged are avoided. Thus, the manufacturing method according to the present disclosure improves assembly efficiency and avoids assembly failure. In particular, the methods of the present disclosure increase the feasibility and convenience of operation for aerogels that are inconvenient to place individually.

The present disclosure also relates to a hot press mold for making a thermal insulation buffer sheet or for carrying out a method of making a thermal insulation buffer sheet, wherein the mold has upper and lower portions that cooperate with each other, and a ram corresponding to one or both openings of the overpack, wherein one or each of the upper and lower portions has a recess corresponding to the shape of the inner layer of the thermal insulation buffer sheet.

The hot press die according to the present disclosure has the advantages of facilitating simple and convenient preparation of the thermal insulation buffer sheet, and improving the structural integrity, stability, thermal insulation performance and elasticity of the thermal insulation buffer sheet.

Drawings

Further features and advantages of the present disclosure will become apparent from the detailed description that follows, taken in conjunction with the accompanying drawings, illustrating by way of example the features of the technology. The drawings are not to scale, but are provided for illustrative purposes only and are not intended to limit the present disclosure in any way.

Fig. 1 shows a schematic view of an integrally folded sheet.

Fig. 2 illustrates a top view of an insulating buffer sheet according to one embodiment of the present disclosure.

FIG. 3 (a) shows a cross section A-A' of one embodiment of the insulating buffer sheet of FIG. 2.

FIG. 3 (B) shows a section B-B' of one embodiment of the insulating buffer sheet of FIG. 2.

FIG. 4 (a) shows a cross section A-A' of one embodiment of the insulating buffer sheet of FIG. 2.

FIG. 4 (B) shows a section B-B' of one embodiment of the insulating buffer sheet of FIG. 2.

FIG. 5 (a) shows a cross section A-A' of one embodiment of the insulating buffer sheet of FIG. 2.

FIG. 5 (B) shows a section B-B' of one embodiment of the insulating buffer sheet of FIG. 2.

Fig. 6 illustrates a top view of an insulating buffer sheet according to another embodiment of the present disclosure.

Detailed Description

the inner layer comprises an aerogel layer,

In some examples, the insulating buffer sheets are symmetrical up-down, symmetrical front-back, and/or symmetrical left-right.

In some examples, the foam layers are alternately stacked with the aerogel layers as inner layers to form a sandwich structure, the number of layers of the sandwich structure being an odd number of at least 3;

preferably, the middle of the sandwich structure is the aerogel layer or the foam layer.

In some examples, a foam layer is laminated to the outside of both the top sheet and the bottom sheet;

the foam layers are the same thickness and are each about 0.5 to about 10 millimeters, preferably about 0.5 to about 4 millimeters;

the aerogel layer has a thickness of about 0.5 to about 15 millimeters, preferably about 0.5 to about 10 millimeters; and is also provided with

The ratio of the thickness of the aerogel layer to the foam layer is from 0.1:1 to 10:1, preferably from 0.3:3 to 3:0.3.

In some examples, the sealed port is formed via bonding;

preferably, the adhesive is a double sided tape, an adhesive that is liquid at room temperature, or a hot melt adhesive that is solid at room temperature;

preferably, the adhesive is a flame retardant adhesive.

In some examples, the sealing port is formed via bonding after folding;

wherein the folding comprises folding the top sheet and the bottom sheet together towards the top sheet direction, or folding the top sheet downwards and folding the bottom sheet upwards and then lapping the top sheet and the bottom sheet together.

In some examples, the overwrap is subjected to heat pressing, or evacuation, or a combination of evacuation and heat pressing.

In some examples, the sheet of overwrap is selected from at least one of the following materials: aramid material, combinations of aramid material and mica, polyethylene terephthalate, polyimide and polypropylene.

In some examples, the foam layer comprises any one or any combination of the following selected from: polyurethane foam, silicone foam, melamine foam and neoprene foam;

Preferably, the foam is in the form of felt, paper or blanket.

In some examples, the aerogel is selected from the group consisting of inorganic aerogels, organic aerogels, and organic-inorganic hybrid aerogels;

preferably, the aerogel is in the form of a fiber reinforced mat, paper or blanket.

In some examples, the inorganic aerogel is based on oxides, carbides, and/or nitrides of: silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium and cerium, preferably the inorganic aerogel is a silica aerogel.

In some examples, the organic aerogel is based on at least one of the following organic polymers: polyamides, polyimides, poly (meth) acrylic acid, poly (meth) acrylates, polyacrylamides, polyacrylonitriles, polystyrenes, polyurethanes, polybutadiene, polyfurfuryl alcohol, polyisocyanates, epoxy resins, polysiloxanes, polyglucosamines, polyethers, chitins and polybenzimidazoles.

The present disclosure provides a method of preparing the thermal insulation buffer sheet according to any one of claims 1-12, comprising the steps of:

c) Sealing an opening of the outer package;

d) Placing an inner layer in the hollow part of the outer package from the other opening of the outer package; and

e) Sealing the other opening of the outer package.

In some examples, when the foam layer is the inner layer, the aerogel layer and the foam layer are placed in the outer package separately in sequence, or at least two, preferably all, of the aerogel layer and the foam layer are placed in the outer package as a whole after lamination.

In some examples, the two openings of the outer package are sealed via an adhesive;

preferably, before the bonding, the top sheet and the bottom sheet are folded together toward the top sheet, or the top sheet is folded downward and the bottom sheet is folded upward and then overlapped.

In some examples, prior to step e), the overwrap is treated by hot pressing, vacuuming, or a combination of vacuuming and hot pressing.

In some examples, the method according to the present disclosure further comprises the step of laminating the foam layer outside the topsheet and/or the backsheet.

The present disclosure also provides a hot press mold for preparing a thermal insulation buffer sheet according to the present disclosure or for carrying out a method according to the present disclosure, wherein the mold has upper and lower portions that cooperate with each other, and a ram corresponding to one or both openings of the overpack, wherein one or each of the upper and lower portions has a recess corresponding to the shape of the inner layer of the thermal insulation buffer sheet.

According to the present disclosure, "cell thermal insulation buffer" refers to a material interposed between individual battery cells in a battery pack structure having a plurality of cells, the material providing thermal insulation; that is, if the battery cells create thermally related "hot spots" or abnormal thermal problems occur such as thermal runaway that may lead to explosion, these materials attempt to insulate each battery cell and retard the transfer of thermal energy. In addition, the material also provides cushioning; that is, when the battery cell expands and contracts in size due to charge and discharge of the battery cell, and the stability of the layered structure inside the battery is affected, the material relieves the excessive expansion and contraction in size of the battery, to bring about the effects of improving the stability of the performance of the battery and prolonging the service life.

Fig. 1 shows a schematic view of an integrally folded sheet. The sheet 10 is folded to form a shape having a top sheet, a bottom sheet 201, left and right side sheets 301 and 401, and front and rear two openings. The top sheet has left and right portions 102 and 101, the left portion 102 of the top sheet having a lap 103 for overlapping the right portion 101 of the top sheet.

Fig. 2 illustrates a top view of an insulating buffer sheet according to one embodiment of the present disclosure. Fig. 6 illustrates a top view of an insulating buffer sheet according to another embodiment of the present disclosure. The insulating buffer sheet 100 of fig. 2 and 6 includes an outer package and an inner layer located in the outer package. The outer package has a top sheet, a bottom sheet, left and right side sheets, and front and rear sealing ports (104, 105) integrally folded via a rectangular sheet, and has a rectangular cross section; wherein the top sheet is formed by overlapping left and right parts (102, 101). The left portion 102 of the top sheet has a lap 103 for overlapping the right portion 101 of the top sheet. In fig. 2, two sealed ports (104, 105) of the overpack are formed via thermocompression bonding. In fig. 6, two sealed ports (104, 105) of the overwrap are formed via the steps of: and folding the top sheet and the bottom sheet together towards the top sheet direction, and then performing thermocompression bonding.

FIG. 3 (a) shows a cross section A-A' of one embodiment of the insulating buffer sheet of FIG. 2. FIG. 3 (B) shows a section B-B' of one embodiment of the insulating buffer sheet of FIG. 2. In fig. 3 (a) and 3 (b), the insulating buffer sheet includes an outer package and an inner layer located in the outer package. The outer package has a top sheet, a bottom sheet 201, left and right side sheets 301, 401, and front and rear sealing ports (104, 105) integrally folded via rectangular sheets, and has a rectangular cross section; wherein the top sheet is formed by overlapping left and right parts (102, 101). The inner layer comprises a foam layer 120, an aerogel felt layer 110 and a foam layer 130 which are alternately stacked in sequence to form a 3-layer sandwich structure.

FIG. 4 (a) shows a cross section A-A' of one embodiment of the insulating buffer sheet of FIG. 2. FIG. 4 (B) shows a section B-B' of one embodiment of the insulating buffer sheet of FIG. 2. In fig. 4 (a) and 4 (b), the insulating buffer sheet includes an outer package and an inner layer located in the outer package. The outer package has a top sheet, a bottom sheet 201, left and right side sheets 301, 401, and front and rear sealing ports (104, 105) integrally folded via rectangular sheets, and has a rectangular cross section; wherein the top sheet is formed by overlapping left and right parts (102, 101). The inner layer comprises an aerogel blanket layer 120, a foam layer 110 and an aerogel blanket layer 130 which are alternately stacked in sequence to form a 3-layer sandwich structure.

FIG. 5 (a) shows a cross section A-A' of one embodiment of the insulating buffer sheet of FIG. 2. FIG. 5 (B) shows a section B-B' of one embodiment of the insulating buffer sheet of FIG. 2. In fig. 5 (a) and 5 (b), the insulating buffer sheet includes an outer package and an inner layer located in the outer package. The outer package has a top sheet, a bottom sheet 201, left and right side sheets 301, 401, and front and rear sealing ports (104, 105) integrally folded via rectangular sheets, and has a rectangular cross section; wherein the top sheet is formed by overlapping left and right parts (102, 101). The inner layer includes an aerogel blanket 110. Foam layers (120, 130) are laminated outside the top sheet (102, 101) and bottom sheet 201, respectively. Two foam layers (120, 130) located outside the overall overwrap may provide good thermal insulation and cushioning. In some examples, the two foam layers are the same thickness and are each about 0.5 to about 10 millimeters, preferably about 0.5 to about 3 millimeters; the aerogel blanket has a thickness of about 0.5 to about 15 millimeters, preferably about 0.5 to about 10 millimeters; and the ratio of the thickness of the aerogel blanket layer to the foam layer is from 0.1:1 to 10:1, preferably from 0.3:3 to 3:0.3. In some examples, the overwrap is subjected to a vacuum. The evacuation helps to provide a good thermal insulation. The evacuation also helps to provide thickness uniformity and helps to reduce the bulk of the overall battery structure. When an abnormal heat problem occurs in one unit cell in the battery pack structure, the foam layer positioned outside the outer package can provide good heat insulation and buffering effects; if the thermal problem is less severe and does not destroy the vacuum state of the overwrap, the vacuum state helps to provide better insulation; if the thermal problem is so severe that the outer package in a vacuum state bursts, air enters the outer package and the aerogel blanket within the outer package rebounds from the vacuum compressed state to a normal thickness, thereby providing a better insulation effect. Thus, such an insulating buffer sheet has several advantages: in the normal working state of the battery, an ultrathin heat insulation buffer space and better thickness uniformity are provided, so that the high integration level of the whole battery pack is assisted, and meanwhile, excellent buffer performance is provided; but also can provide the heat insulation performance which is regulated according to the thermal runaway state when the battery is in thermal runaway, thereby maximally utilizing the dual advantages of buffering and heat insulation and reducing the disadvantages of space and poor uniformity caused by thickness.

The symmetrically arranged structure helps to maintain a uniform state between the unit cells, so that the life and cycle stability of the battery pack structure can be improved.

In some examples, foam layers are stacked alternately as an inner layer with the aerogel layers, preferably aerogel blanket layers, to form a sandwich structure. The number of layers of the sandwich structure is an odd number of at least 3, for example 3, 5, 7, 9 or 11, etc.

Preferably, the middle most of the sandwich structure is an aerogel layer, preferably an aerogel felt layer, or a foam layer.

The aerogel blanket and/or foam layer provides insulation and cushioning to the insulation buffer.

According to the present disclosure, double-sided tape (not shown in the drawings) may be disposed on the top and bottom surfaces of the thermal insulation buffer sheet. Double sided tape may be used to adhere the insulating buffer sheet to the battery cell or to place the insulating buffer sheet in a battery block or pack. Double sided adhesives comprising flame retardant adhesives are preferred. The area of the double-sided adhesive tape may be as large as the entire top and/or bottom surface, or may be 1 or more strips of adhesive tape as desired.

The double-sided tape may be replaced with other adhesives commonly used if desired. There are no particular restrictions on the type of other adhesives, either adhesives that are liquid at room temperature (about 25 ℃) or hot melt adhesives that are solid at room temperature may be used in the present disclosure. The adhesive is preferably a flame retardant adhesive. The double-sided tape is preferably a flame-retardant double-sided tape.

Unless otherwise indicated or clearly contradicted, references to the thickness of the aerogel layer and the thickness of the foam layer hereinafter mean a single layer thickness.

In some examples, the aerogel layer, particularly the ratio of the thickness of the aerogel blanket layer to the thickness of the foam layer, is from 0.1:1 to 10:1, preferably from 0.3:3 to 3:0.3.

In some examples, the foam layer has a thickness of about 0.5 to about 10 millimeters, preferably about 0.5 to about 3 millimeters.

In some examples, the aerogel layer, and particularly the aerogel blanket layer, has a thickness of about 0.5 to about 15 millimeters, preferably about 0.5 to about 10 millimeters.

In some examples, the thickness of the sheet used to form the outer layer is from about 0.02 to about 0.3 millimeters, preferably from about 0.05 to about 0.2 millimeters.

In some examples, the total thickness of the insulating buffer sheet is about 1 to about 20 millimeters, preferably about 1 to about 15 millimeters.

In some examples, the left and right portions of the top sheet of the outer package overlap via bonding.

In some examples, the sealed port of the overpack is formed via bonding. In some examples, the sealed port is formed via folding and then via bonding. Folding includes folding the top sheet and the bottom sheet together toward the top sheet, or folding the top sheet downward and folding the bottom sheet upward and then overlapping them together.

In some examples, the bonding is by adhesive at the top and bottom surfaces of the inner layer that are in contact with the inside of the top sheet and the inside of the bottom sheet of the outer package.

Preferably, the adhesive is a double sided tape, an adhesive that is liquid at room temperature, or a hot melt adhesive that is solid at room temperature, preferably the adhesive is a flame retardant adhesive.

In some examples, the overwrap is subjected to a heat press or a vacuum, or a heat press plus vacuum process. The vacuum is helpful in providing good thermal insulation and better thickness uniformity.

In fig. 3 (b), 4 (b) and 5 (b), the front and rear sealing ports (104, 105) have widths 14 and 15, respectively. The width of the sealing port should be wide enough to adequately seal the material of the inner layer in the insulating buffer sheet and prevent the inorganic matter in the inner layer from falling off, and also should be sufficient to allow the insulating buffer sheet to withstand handling during manufacture of the battery block or pack and subsequent use without breaking the peripheral seal. Preferably, widths 14 and 15 are equal and preferably less than 10mm. In some examples, the front and back sealing ports (104, 105) each have a width of 2-10 mm.

In some examples, the sheet for forming the overwrap comprises at least one selected from the group consisting of: aramid material, combinations of aramid material and mica, polyethylene terephthalate, polyimide and polypropylene. Such materials provide flame retardancy, fire resistance and high temperature resistance. In some examples, the aramid material, or a combination of aramid material and mica, is in the form of paper, floe, fibrids, or mixtures thereof. In some examples, the polyethylene terephthalate, polyimide, or polypropylene is in the form of a film. In some examples, the overpack comprises 50-70 wt% uniformly distributed mica and 30-50 wt% aramid material, based on the total weight of the overpack. In some examples, the overpack comprises 50-60 wt% uniformly distributed mica and 40-50 wt% aramid material, based on the total weight of the overpack.

Preferably, the sheet material used to form the overwrap is an aramid material. Preferably, at least about 50% by weight of mica is included in the outer package to provide the desired dimensional stability of those layers under flame conditions, as evidenced by minimal crack formation, shrinkage and expansion of the outer package under flame. Further, in the case of exterior packaging, it is useful that the amount of mica is more than 70% by weight from the viewpoints of fire resistance and dimensional stability. However, it is believed that when the amount of mica in the outer package is increased to more than 70 weight percent, the outer layer is more prone to mica shedding, and therefore in some applications, an amount of mica greater than 70 weight percent is undesirable.

By homogeneously distributed mica is meant that the mica can be homogeneously distributed throughout the thickness of the overwrap or in the entire concentrated (concentrated) planar area of the outer layer, the mica can be homogeneously and areally distributed, the concentrated planar area being closer to one of the surfaces of the layer. Implicit in this definition is that the mica is sufficiently distributed to provide the desired properties of the final insulating buffer sheet structure.

The mica may comprise mica of the muscovite or phlogopite type or a blend thereof, and may be calcined or uncalcined mica. As used herein, "calcined mica" refers to mica obtained by heating natural mica to high temperatures (typically above 800 ℃, sometimes above 950 ℃). This treatment removes water and impurities and improves the temperature resistance of the mica. Calcined mica is generally used in the form of plate-like particles, and muscovite-type mica is preferred. As used herein, "uncalcined mica" refers to mica in a substantially pure natural form, which is preferably homogenized and purified to remove defects and impurities. Due to the large size of the natural mica flakes, the uncalcined mica can form a very porous mica layer. The preferred mica for use in the first outer layer and/or the second outer layer is calcined mica because calcined mica has improved dielectric properties and corona resistance compared to uncalcined mica.

The overwrap may have a preferred thickness of 0.01-0.25mm and a basis weight of 10-300 grams per square meter. In some examples, the overwrap may have a thickness of 0.03-0.1 mm. In some examples, the overwrap may have a basis weight of 45-120 grams per square meter.

In some examples, the foam layer comprises closed cell foam, open cell foam, or a combination thereof. The foam may be selected from polyurethane foam, silicone foam, melamine foam, neoprene foam, and any combination thereof.

There are no specific limitations on Polyurethane (PU) foam, and conventional PU foam may be used herein as long as they do not adversely affect the purposes of the present disclosure. Methods of making polyurethane foams (e.g., flexible PU foams) are known in the art and are disclosed, for example, in Plastics Manual, volume 7, polyurethane, becker/Braun, pages 170-235; version 2, carl Hanser Verlag publication. Conventionally, PU foam (e.g., flexible, semi-flexible, and rigid PU foam) can be prepared by reacting polyols with polyfunctional isocyanates such that NCO and OH groups form urethane linkages through addition reactions, and polyurethane is typically foamed with carbon dioxide generated in situ from isocyanate reaction with water, but other volatile non-reactive solvents and gases (e.g., acetone, pentane, and infused carbon dioxide) and mechanical foaming can also be used to form cell spaces within the foam.

Silicone foam compositions are known in the art. For example, reference may be made to U.S. Pat. nos. 4,189,545;3,923,705;4,599,367 and 3,436,366. Silicone foam is typically prepared from a foamable composition comprising a vinyl-containing siloxane, a hydride-containing siloxane, a hydroxyl source, and a platinum catalyst. These compositions undergo curing to form foam.

Melamine foam is known, for example, from us patent No. 6,350,511B2. For example, melamine foam may be produced by foaming an aqueous solution of a melamine foam condensate comprising an emulsifier, a curing agent, and a foaming agent, such as a C4-C8 hydrocarbon, and curing the melamine foam condensate at an elevated temperature.

Neoprene foam is well known in the art. They can be prepared from Neoprene Latex as discussed in "Neoprene Latex", john C. Carl, E.I. du Pont de Nemours & Co., pages 89-94 (1962).

In the inner layer, the foam layer may have a preferred thickness of 0.5-10mm and a basis weight of 100-2500 grams per square meter.

An aerogel layer, in particular an aerogel blanket, is located as an inner layer in the outer package.

Aerogels are porous materials comprising open cells having an interconnected structure framework in which a corresponding network of cells is integrated into the framework, the network of cells having a interstitial phase therein, the interstitial phase comprising primarily a gas, such as air. Aerogels are characterized by low density, high porosity, large surface area, and small pore size, and therefore, aerogels can provide good thermal insulation and cushioning properties.

In some examples, the aerogel can have one or more of the following physical and structural properties (as measured by nitrogen porosimetry): (a) an average pore diameter of about 2nm to about 100nm, (b) a porosity of at least 80% or greater, and (c) about 20m ² Surface area/g or greater.

In some examples, the aerogel may also have one or more of the following physical properties: (d) A pore volume of about 2.0mL/g or greater, preferably about 3.0mL/g or greater; (e) A density of about 0.50g/cc or less, preferably about 0.25g/cc or less; and (f) at least 50% of the pore volume comprises pores having a pore diameter of from 2 to 50 nm.

In some examples, the aerogel is selected from the group consisting of inorganic aerogels, organic aerogels, and organic-inorganic hybrid aerogels.

The inorganic aerogel may be based on oxides, carbides and/or nitrides of: silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium and cerium, preferably the inorganic aerogel is a silica aerogel.

The organic aerogel may be based on at least one of the following organic polymers: polyamides, polyimides, poly (meth) acrylic acid, poly (meth) acrylates, polyacrylamides, polyacrylonitriles, polystyrenes, polyurethanes, polybutadiene, polyfurfuryl alcohol, polyisocyanates, epoxy resins, polysiloxanes, polyglucosamines, polyethers, chitins and polybenzimidazoles.

The organic-inorganic hybrid aerogel may be based on any combination of inorganic substances selected from the following oxides, carbides and/or nitrides: silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium and cerium, the organic polymer is selected from the group consisting of polyamides, polyimides, poly (meth) acrylic acids, poly (meth) acrylates, polyacrylamides, polyacrylonitriles, polystyrenes, polyurethanes, polybutadiene, polyfurfuryl alcohol, polyisocyanates, epoxy resins, polysiloxanes, polyglucosamine polyethers, chitins and polybenzimidazoles. Preferably, the organic-inorganic hybrid aerogel is selected from the group consisting of silica-polysiloxanes, silica-polyethers, silica-poly (meth) acrylates and silica-chitosans.

Preferably, the aerogel is a fiber reinforced aerogel blanket. Fiber reinforced aerogels can improve mechanical properties of the aerogel, such as flexibility, resilience, uniformity, and/or structural stability.

The fibers may be selected from glass fibers, ceramic fibers, polyacrylonitrile (PAN) fibers, and oxidized polyacrylonitrile fibers. The glass fibers may be selected from, for example, S-glass, 901 glass, 902 glass, 475 glass, E-glass, and the like.

In some examples, the fiber-reinforced aerogel comprises an aerogel attached to fibers.

The aerogel can be in the form of a blanket, paper, or blanket. In some examples, the blanket, paper or blanket of silica aerogel used in the inner layer also contains an organic or inorganic binder, and one useful and exemplary organic binder is an acrylic binder.

Aerogel and fiber reinforced aerogel blankets are commercially available.

In the inner layer, the aerogel containing blanket, paper or blanket may have a thickness of 0.3-15mm and a basis weight of 40-3300 grams per square meter. In some examples, the aerogel blanket may have a thickness of 0.5-8 mm. In some examples, the aerogel containing blanket, paper or blanket can have a basis weight of 70-1500 grams per square meter.

The foam layer may have a thickness of 0.5-10mm and a basis weight of 100-5000 grams per square meter. In some examples, the foam layer may have a thickness of 0.5-4 mm. In some examples, the foam layer may have a basis weight of 100-2000 grams per square meter.

In some examples, the insulating buffer sheet has a total basis weight of about 300-500000 grams per square meter, for example about 30000-5000 grams per square meter. If the central insulating region of the insulating buffer sheet is separated from the peripheral sealing region, it is found that the insulating region occupies a substantial portion of the basis weight; likewise, the basis weight of the narrow peripheral seal itself is only about 2-150 grams per square meter.

As used herein, the term aramid floe refers to aramid fibers having a short length and commonly used to make wet-laid sheets and/or paper. Typically, the aramid floe has a length of about 3 to about 20 millimeters. The preferred length of the aramid floe is about 3 to about 7 millimeters. Aramid floe is typically produced by cutting continuous fibers to the desired length using methods well known in the art.

As used herein, the term aromatic polyamide (aramid) refers to an aromatic polyamide (aromatic polyamide) in which at least 85% of the amide (-CONH-) linkages are directly attached to two aromatic rings. Optionally, additives may be used with the aramid and may be dispersed throughout the polymer structure. It has been found that up to about 10 wt% of other support materials can be blended with the aramid. It has also been found that copolymers having up to about 10% of other diamines substituted for the diamines of the aromatic polyamide or up to about 10% of other diacid chlorides substituted for the diacid chlorides of the aromatic polyamide can be used. The preferred aromatic polyamide is meta-aromatic polyamide. An aramid polymer is considered to be a meta-aramid when two rings or groups are meta-oriented relative to each other along a molecular chain. A preferred meta-aramid is poly (meta-phenylene isophthalamide) (MPD-I). U.S. Pat. nos. 3,063,966;3,227,793;3,287,324;3,414,645 and 5,667,743 describe methods for making aramid fibers that can be used to make aramid floe.

Alternatively, the aramid floe may be para-aramid or aramid copolymer. An aramid polymer is considered to be a para-aramid when two rings or groups are para-oriented relative to each other along a molecular chain. Methods of making para-aramid fibers are generally disclosed in, for example, U.S. Pat. nos. 3,869,430;3,869,429; and 3,767,756. One preferred para-aramid is poly (p-phenylene terephthalamide); one preferred para-aramid copolymer is a copolymer (p-phenylene/3, 4' -diphenyl ester terephthalamide). Preferred aramid floe is meta-aramid floe, and particularly preferred is floe made from meta-aramid poly (meta-phenylene isophthalamide) (MPD-I).

As used herein, the term fibrids refers to very small non-particulate fibrous or membranous particles, at least one of the three dimensions of which is of a small order of magnitude relative to the largest dimension. These particles are prepared by precipitating a solution of the support material under high shear using a non-solvent, as disclosed, for example, in U.S. Pat. nos. 2,988,782 and 2,999,788. Aramid fibrids are non-granular, film-like particles of aramid having a melting point or decomposition point above 320 ℃. The preferred aramid fibrids are meta-aramid fibrids, and particularly preferred fibrids made from meta-aramid poly (meta-phenylene isophthalamide) (MPD-I).

The maximum dimensional length of the fibrids is typically in the range of about 0.1mm to about 1mm with an aspect ratio of length to width of about 5:1 to about 10:1. The thickness dimension is on the order of a fraction of microns, e.g., about 0.1 microns to about 1.0 microns. Although not required, it is preferred that the aramid fibrids be incorporated into the layer while the fibrids are in an never-dried (receiver-dried) state. The first and second outer layers comprise an aramid material in the form of floe, fibrids, or mixtures thereof. When a mixture of floc and fibrids is used for the aramid, the preferred calculated weight ratio of floc to fibrid is 0.5-4.0, more preferably 0.8-2.0.

Polyethylene terephthalate (PET) films, such as Mylar (Mylar) available from Dupont (Dupont), can be prepared by heating dimethyl terephthalate and ethylene glycol with the aid of a relevant catalyst, transesterifying and vacuum polycondensing, biaxially stretching.

Polyimide (PI) films can be prepared by low temperature solution polycondensation of dianhydrides with diamines in polar solvents such as dimethylformamide, dimethylacetamide, and the like, to synthesize polyamic acids, which are then dehydrated at high temperature to effect imide cyclization. For example, kapton membranes available from Dupont (Dupont) can be prepared by thermal imine or imine cyclization using pyromellitic dianhydride monomer as a starting material.

In a preferred embodiment, in order to uniformly and continuously bond the surface of each paper layer or film to the surface of the support layer, a liquid adhesive is applied to at least one surface of the layer in a relatively uniform manner. The adhesive may be applied to the paper layer or film, i.e., the inner layer, using any method that applies the adhesive uniformly to one side of the layer; such methods include those involving roll coating or knife coating or spray coating, and are not limited to these methods. Preferably, the adhesive is applied to a uniform thickness and is continuous in the insulation sheet structure.

The thermal insulation buffer sheet according to the present disclosure may be prepared using a conventional preparation method, and may also be prepared using a method according to the present disclosure.

In a conventional manufacturing method, each layer is manufactured separately and then combined with an adhesive layer provided therebetween, wherein the layers are a first outer layer, an inner layer, and then a second outer layer in that order. And hot-pressing the peripheries of the first outer layer and the second outer layer after sequentially superposing and combining the first outer layer, the inner layer and the second outer layer. The first outer layer and the second outer layer may be directly bonded to the inner layer in the insulated region by using a continuous or discontinuous adhesive layer; while the first outer layer and the second outer layer may be directly bonded to each other in the peripheral sealing region by preferentially using a continuous adhesive layer.

The present disclosure provides a method of preparing a thermal insulation buffer sheet, comprising the steps of:

c) Sealing an opening of the outer package;

e) Sealing the other opening of the outer package.

In some examples, when there is a foam layer on the outside of the outer package, the method according to the present disclosure further comprises the step of laminating the foam layer outside of the top sheet and/or the bottom sheet of the outer package.

Claims

1. The heat insulation buffer sheet comprises an outer package and an inner layer positioned in the outer package,

The inner layer comprises an aerogel layer,

2. The insulating buffer sheet of claim 1, wherein the insulating buffer sheet is symmetrical up-down, symmetrical front-back, and/or symmetrical left-right.

3. The thermal insulation buffer sheet according to claim 1 or 2, wherein the foam layers are alternately stacked with the aerogel layers as inner layers to form a sandwich structure, the number of layers of the sandwich structure being an odd number of at least 3;

4. The thermal insulation buffer sheet according to any one of claims 1 to 3, wherein a foam layer is laminated outside both the top sheet and the bottom sheet;

5. The insulating buffer sheet of any of claims 1-4, wherein the sealed port is formed via bonding;

preferably, the adhesive is a flame retardant adhesive.

6. The insulating buffer sheet of any of claims 1-5, wherein the sealing port is formed via bonding after folding;

7. The insulating buffer sheet of any of claims 1-6, wherein the overwrap is subjected to heat pressing, or vacuuming, or a combination of vacuuming and heat pressing.

8. The insulating buffer sheet of any of claims 1-7, wherein the sheet of overwrap is selected from at least one of the following materials: aramid material, combinations of aramid material and mica, polyethylene terephthalate, polyimide and polypropylene.

9. The insulating buffer sheet of any of claims 1-8, wherein the foam layer comprises any one or any combination of the following selected from: polyurethane foam, silicone foam, melamine foam and neoprene foam;

Preferably, the foam is in the form of felt, paper or blanket.

10. The thermal insulation buffer sheet according to any one of claims 1-9, the aerogel being selected from the group consisting of inorganic aerogels, organic aerogels, and organic-inorganic hybrid aerogels;

11. The insulating buffer sheet of claim 10, wherein the inorganic aerogel is based on oxides, carbides, and/or nitrides of: silicon, aluminum, titanium, zirconium, hafnium, yttrium, vanadium and cerium, preferably the inorganic aerogel is a silica aerogel.

12. The insulating buffer sheet of claim 11, wherein the organic aerogel is based on at least one of the following organic polymers: polyamides, polyimides, poly (meth) acrylic acid, poly (meth) acrylates, polyacrylamides, polyacrylonitriles, polystyrenes, polyurethanes, polybutadiene, polyfurfuryl alcohol, polyisocyanates, epoxy resins, polysiloxanes, polyglucosamines, polyethers, chitins and polybenzimidazoles.

13. A method of preparing the thermal insulation buffer sheet according to any one of claims 1-12, comprising the steps of:

c) Sealing an opening of the outer package;

e) Sealing the other opening of the outer package.

14. The method according to claim 13, wherein when the foam layer is an inner layer, the aerogel layer and the foam layer are placed in the outer package separately in sequence, or at least two, preferably all, of the aerogel layer and the foam layer are placed in the outer package as a whole after lamination.

15. The method of claim 13 or 14, wherein the two openings of the outer package are sealed via an adhesive;

16. The method of any one of claims 13-15, wherein prior to step e), the overwrap is treated by hot pressing, evacuating, or a combination of evacuating and hot pressing.

17. The method of any one of claims 13-16, further comprising the step of layering the foam layer outside of the topsheet and/or backsheet.

18. Hot-pressing mould for preparing a thermal insulation buffer sheet according to any one of claims 1-12 or for carrying out the method according to any one of claims 13-17, wherein the mould has upper and lower parts cooperating with each other and a ram corresponding to one or both openings of the outer package, wherein one or each of the upper and lower parts has a recess corresponding to the shape of the inner layer of the thermal insulation buffer sheet.