Packaging film for battery thermal insulation sheet and preparation method and application thereof

Abstract

The present invention discloses a packaging film for a battery thermal insulation sheet and a preparation method and application thereof, and relates to the technical field of packaging films. By forming a structure of an insulating layer, a first adhesive layer, a barrier layer, a second adhesive layer and a heat-sealing layer, the packaging film is suitable for use as a phase-change thermal insulation packaging material, and can ensure that the product has the characteristics of high barrier to water and oxygen, and has the advantages of low water permeability, low oxygen permeability, high breaking force and high insulation, and provides support for the development of new thermal insulation sheets.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging films, and in particular to a packaging film for a battery thermal insulation sheet, and a preparation method and application thereof. Background Art

[0002] Thermal runaway is a critical safety issue for both lithium and sodium batteries. This phenomenon occurs when a battery becomes self-destructive due to uncontrolled thermal conditions, resulting in potentially dangerous consequences. Thermal runaway is critical not only for battery manufacturers but also for end users to ensure safety in a variety of applications, from smartphones to electric vehicles.

[0003] At present, the means to prevent thermal runaway include water cooling, thermal insulation and flame retardant, directional eruption, etc. An efficient heat-resistant and flame-retardant insulation layer is formed between the battery cells. When a single battery cell has thermal runaway, the presence of the thermal insulation sheet can prevent the heat from spreading to other surrounding battery cells, thereby preventing the occurrence of chain thermal runaway. However, the current thermal insulation sheets are relatively single functional materials, and their main function is thermal insulation. When the battery heats up, the heat can only be isolated in a limited space, and the heat is taken away by the cooling system. This not only consumes energy, but also fails to effectively utilize the excess heat.

[0004] Phase change material insulation sheets can effectively solve the above defects, but phase change materials have strict requirements on water vapor and oxygen. The current pure organic packaging materials cannot meet the requirements of low water permeability, low oxygen permeability, high rupture force and high insulation.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a packaging film for a battery thermal insulation sheet, a preparation method and application thereof, aiming to provide a packaging film with low water permeability, low oxygen permeability, high rupture force and high insulation.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a packaging film for a battery thermal insulation sheet, comprising a barrier layer, the barrier layer having a first surface and a second surface opposite to the first surface, a first adhesive layer and an insulating layer are sequentially arranged on the first surface, and a second adhesive layer and a heat sealing layer are sequentially arranged on the second surface.

[0009] In an optional embodiment, a first anti-oxidation layer is further provided between the barrier layer and the first adhesive layer, and a second anti-oxidation layer is further provided between the barrier layer and the second adhesive layer;

[0010] The materials of the first anti-oxidation layer and the second anti-oxidation layer are independently selected from at least one of fluorocarbon resin, chromium nitrate, zinc nitrate, zinc oxide and modified polyolefin resin;

[0011] Preferably, the thickness of the first anti-oxidation layer and the second anti-oxidation layer are both 0.01 μm-1.0 μm;

[0012] More preferably, the materials of the first anti-oxidation layer and the second anti-oxidation layer are both chromium nitrate, and the chromium content is 80ppm-100ppm.

[0013] In an optional embodiment, the barrier layer is selected from at least one of aluminum foil, aluminized film, copper foil, iron foil and steel foil;

[0014] When the material of the barrier layer is selected from at least one of aluminum foil, copper foil, iron foil and steel foil, the thickness of the barrier layer is 10 μm-100 μm;

[0015] When the barrier layer is made of an aluminum-plated film, the thickness of the aluminum-plated film is controlled to be 0.038 μm-1 μm; preferably, the aluminum-plated film includes a polyester film with a thickness of 12 μm-100 μm, and an aluminum-plated layer is provided on both sides of the polyester film;

[0016] Preferably, the barrier layer is an aluminum foil with a thickness of 20 μm-60 μm.

[0017] In an optional embodiment, the materials of the first adhesive layer and the second adhesive layer are independently selected from at least one of polyurethane resin, polyolefin resin, polyacrylic resin, hot melt adhesive, epoxy resin, urea-formaldehyde resin, phenolic resin and melamine-formaldehyde;

[0018] Preferably, the thickness of the first adhesive layer and the second adhesive layer are both 2 μm-10 μm;

[0019] More preferably, the first adhesive layer and the second adhesive layer are both made of polyurethane resin and have a thickness of 4 μm-5 μm.

[0020] In an optional embodiment, the material of the insulating layer is selected from at least one of polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polystyrene, polyamide, polyimide, polyethylene terephthalate and polyethylene naphthalate;

[0021] Preferably, the thickness of the insulating layer is 3 μm-100 μm;

[0022] Preferably, the insulating layer is a polyethylene terephthalate film with a thickness of 3 μm-50 μm.

[0023] In an optional embodiment, the heat seal layer is made of polyolefin resin;

[0024] Preferably, the material of the heat-sealing layer is selected from at least one of polypropylene, polyethylene, poly-1-butene and poly-4-methyl-1-pentene; more preferably, the heat-sealing layer is selected from at least one of cast polypropylene film and polyethylene film;

[0025] Preferably, the thickness of the heat-sealing layer is 10 μm-100 μm; more preferably 20 μm-80 μm;

[0026] Preferably, the heat-sealing layer is a multi-layer structure.

[0027] In an optional embodiment, a slippery layer is further formed on the heat-sealing layer, and the material of the slippery layer is selected from at least one of erucamide, oleamide, behenamide, ethylenebisoleamide and biserucamide;

[0028] Preferably, the material of the slippery layer is selected from at least one of erucamide and oleamide;

[0029] Preferably, when preparing the slippery layer, the coating amount is controlled to be 10 mg / m 2 -20mg / m 2 .

[0030] In a second aspect, the present invention provides a method for preparing a packaging film for a battery thermal insulation sheet according to any one of the aforementioned embodiments, comprising:

[0031] providing a barrier layer material, the barrier layer material having a first surface and a second surface opposite to the first surface;

[0032] Forming a first anti-oxidation layer, a first adhesive layer and an insulating layer in sequence on a first surface of the barrier layer material, and forming a second anti-oxidation layer, a second adhesive layer and a heat-sealing layer in sequence on a second surface;

[0033] Preferably, the anti-oxidation layer material is firstly coated on the first surface and the second surface of the barrier layer material, and then dried to form the first anti-oxidation layer and the second anti-oxidation layer;

[0034] Coating the adhesive layer material on the second anti-oxidation layer, drying and laminating it with the heat-sealing layer film, so as to form the second adhesive layer and the heat-sealing layer on the second surface;

[0035] Coating an adhesive layer material on the first anti-oxidation layer, and thermally bonding the adhesive layer material to the insulating layer film after drying to form a first adhesive layer and an insulating layer on the first surface;

[0036] More preferably, the method further comprises: after forming the first adhesive layer and the insulating layer, performing an aging treatment at 40° C.-85° C. for 72 h-144 h, and then coating a lubricant on the insulating layer or the heat-sealing layer.

[0037] In a third aspect, the present invention provides a battery thermal insulation sheet, comprising a thermal insulation sheet and a packaging film for packaging the thermal insulation sheet, wherein the packaging film is a packaging film for a battery thermal insulation sheet in any of the aforementioned embodiments or a packaging film for a battery thermal insulation sheet prepared by the preparation method of the aforementioned embodiments;

[0038] Preferably, the thermal insulation sheet contains a phase change material.

[0039] In a fourth aspect, the present invention provides a secondary battery, comprising the battery thermal insulation sheet of the aforementioned embodiment.

[0040] The present invention has the following beneficial effects: by forming a structure of an insulating layer, a first adhesive layer, a barrier layer, a second adhesive layer and a heat-sealing layer, the present invention is suitable as a phase change thermal insulation packaging material, which can ensure that the product has the characteristics of high barrier to water and oxygen, and has the advantages of low water permeability, low oxygen permeability, high breaking force and high insulation, thus providing support for the development of new thermal insulation sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 It is the encapsulation membrane structure of the traditional aerogel insulation sheet;

[0043] Figure 2 A schematic diagram of the packaging film structure provided by an embodiment of the present invention.

[0044] 1-insulating layer; 2-hot melt adhesive; 3-insulating layer; 4-first bonding layer; 5-first anti-oxidation layer; 6-barrier layer; 7-second anti-oxidation layer; 8-second bonding layer; 9-heat sealing layer; 10-slip layer. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0046] Figure 1 A conventional aerogel thermal insulation sheet packaging film structure is provided, including an insulating layer 1 and a hot melt adhesive 2, which has a simple structure and cannot meet the requirements of low water permeability, low oxygen permeability, high rupture force and high insulation.

[0047] For this reason, Figure 2As shown, an embodiment of the present invention provides a packaging film for a battery heat insulation sheet, including a barrier layer 6, the barrier layer 6 has a first surface and a second surface opposite to the first surface, a first anti-oxidation layer 5, a first adhesive layer 4 and an insulating layer 3 are sequentially arranged on the first surface, and a second anti-oxidation layer 7, a second adhesive layer 8 and a heat sealing layer 9 are sequentially arranged on the second surface. By forming a composite layer structure, it can effectively block water and oxygen, and has a certain burst strength effect. The heat insulation sheet using this packaging film has a long service life and stable performance.

[0048] In some embodiments, the barrier layer 6 is selected from at least one of aluminum foil, aluminum-plated film, copper foil, iron foil and steel foil, and the barrier layer 6 can be any one or more of the above.

[0049] When the material of the barrier layer 6 is selected from at least one of aluminum foil, copper foil, iron foil and steel foil, the thickness of the barrier layer 6 is 10 μm-100 μm, such as 10 μm, 20 μm, 30 μm, 50 μm, 60 μm, 80 μm, 100 μm, etc. When the material of the barrier layer 6 is an aluminum-plated film, the aluminum-plated film includes a polyester film with a thickness of 12 μm-100 μm, and aluminum coatings are provided on both sides of the polyester film, and the thickness of the aluminum coatings on both sides is controlled to be 0.038 μm-1 μm.

[0050] In a preferred embodiment, the barrier layer 6 is an aluminum foil with a thickness of 20 μm-60 μm. Aluminum foil is easily available and has a more prominent barrier effect, thereby having a higher cost-performance ratio.

[0051] In some embodiments, the materials of the first anti-oxidation layer 5 and the second anti-oxidation layer 7 are independently selected from at least one of fluorocarbon resin, chromium nitrate, zinc nitrate, zinc oxide and modified polyolefin resin. The materials of the first anti-oxidation layer 5 and the second anti-oxidation layer 7 can be the same or different, and can be selected from any one or more of the above. The thickness of the first anti-oxidation layer 5 and the second anti-oxidation layer 7 is 0.01 μm-1.0 μm. If the thickness of the anti-oxidation layer is too large, it will affect the composite bonding performance, and it is preferably controlled to be less than 1.0 μm.

[0052] Specifically, the modified polyolefin resin is obtained by modifying a polyolefin resin grafted with maleic anhydride, and is a commercially available material, such as a product of model PMA-KE that can be purchased from Toyobo Co., Ltd. of Japan.

[0053] In a preferred embodiment, the first anti-oxidation layer 5 and the second anti-oxidation layer 7 are both made of chromium nitrate, and the chromium content is 80ppm-100ppm, such as 80ppm, 85ppm, 90ppm, 95ppm, 100ppm, etc. Chromium nitrate is coated on both sides of the barrier layer 6, and after drying, the chromium content on the aluminum foil and other materials is detected, and the chromium content is 80ppm-100ppm.

[0054] In some embodiments, the materials of the first adhesive layer 4 and the second adhesive layer 8 are independently selected from at least one of polyurethane resin, polyolefin resin, polyacrylic resin, hot melt adhesive, epoxy resin, urea-formaldehyde resin, phenolic resin and melamine-formaldehyde. The materials of the first adhesive layer 4 and the second adhesive layer 8 can be the same or different, and can be selected from any one or more of the above. The thickness of the first adhesive layer 4 and the second adhesive layer 8 is 2μm-10μm, such as 2μm, 5μm, 8μm, 10μm, etc.

[0055] In a preferred embodiment, the first adhesive layer 4 and the second adhesive layer 8 are both polyurethane resins, and have a thickness of 4 μm-5 μm, which is a dry thickness, that is, a thickness after drying. Specifically, the thickness may be 4.0 μm, 4.3 μm, 4.5 μm, 4.8 μm, 5.0 μm, etc.

[0056] In some embodiments, the material of the insulating layer 3 is selected from at least one of polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polystyrene, polyamide, polyimide, polyethylene terephthalate and polyethylene naphthalate. The material of the insulating layer 3 can be any one or more of the above materials and meet the flame retardant requirements of UL94-V2 and above. The thickness of the insulating layer 3 is 3μm-100μm, such as 3μm, 10μm, 30μm, 50μm, 80μm, 100μm, etc.

[0057] In a preferred embodiment, the insulating layer 3 is a polyethylene terephthalate film with a thickness of 3 μm-50 μm. By optimizing the material of the insulating layer, the voltage breakdown resistance can be further improved. The insulating layer film is one of colorless and transparent, colored and transparent, and colored and opaque.

[0058] In some embodiments, the material of the heat sealing layer 9 is polyolefin resin, and the specific material is not limited. Preferably, the material of the heat sealing layer 9 is selected from at least one of polypropylene, polyethylene, poly-1-butene and poly-4-methyl-1-pentene, and the material of the heat sealing layer 9 can be any one or more of the above, and the heat sealing layer 9 can be a multi-layer structure, which can be any one of a four-layer, three-layer, two-layer or single-layer structure, and the thickness is 10μm-100μm, such as 10μm, 30μm, 50μm, 80μm, 100μm, etc.

[0059] In a preferred embodiment, the heat sealing layer 9 is selected from at least one of a cast polypropylene film and a polyethylene film, and has a thickness of 20 μm-80 μm, such as 20 μm, 40 μm, 60 μm, 80 μm, etc. By optimizing the material and thickness of the heat sealing layer 9, a better packaging effect can be achieved and the burst pressure of the package can be increased.

[0060] In some embodiments, a slippery layer 10 is formed on the heat-sealing layer 9 or the insulating layer 3 to further improve the effect of blocking water and oxygen. In a preferred embodiment, the slippery layer 10 is located on the heat-sealing layer 9 to better play its role.

[0061] Furthermore, the material of the slippery layer is selected from at least one of erucamide, oleamide, behenamide, ethylenebisoleamide and biserucamide, and the material of the slippery layer may be any one or more of the above.

[0062] In a preferred embodiment, the material of the slippery layer is selected from at least one of erucic acid amide and oleic acid amide. When preparing the slippery layer, the coating amount is controlled to be 10 mg / m 2 -20mg / m 2 (Specifically, it can be 10mg / m 2 , 15mg / m 2 , 20mg / m 2 By controlling the material and coating amount of the slippery layer, the water and oxygen barrier properties of the product can be further improved.

[0063] like Figure 2 As shown, an embodiment of the present invention provides a method for preparing a packaging film for a battery thermal insulation sheet, comprising: providing a barrier layer 6 material, the barrier layer 6 material having a first surface and a second surface opposite to the first surface; forming a first anti-oxidation layer 5, a first adhesive layer 4 and an insulating layer 3 on the first surface of the barrier layer 6 material in sequence, and forming a second anti-oxidation layer 7, a second adhesive layer 8 and a heat-sealing layer 9 on the second surface in sequence.

[0064] It should be noted that the formation order of each layer is not limited, and the following can be obtained in the end: Figure 2 The structure of each layer is as shown, and the material and thickness of each layer can be referred to in the parameter manual for the packaging film product for battery insulation sheet.

[0065] In some embodiments, a method for preparing a packaging film for a battery thermal insulation sheet comprises the following steps:

[0066] S1. Forming the first anti-oxidation layer 5 and the second anti-oxidation layer 7

[0067] First, the anti-oxidation layer material is coated on the first surface and the second surface of the barrier layer 6 material, and then dried to form the first anti-oxidation layer 5 and the second anti-oxidation layer 7.

[0068] That is to say, the material of the anti-oxidation layer is the material corresponding to the first anti-oxidation layer 5 and the second anti-oxidation layer 7, such as chromium nitrate, but not limited thereto.

[0069] S2, forming the second adhesive layer 8 and the heat sealing layer 9

[0070] The adhesive layer material is coated on the second anti-oxidation layer 7, dried and thermally bonded to the heat-sealing layer 9 film to form the second adhesive layer 8 and the heat-sealing layer 9 on the second surface.

[0071] Specifically, the adhesive layer material may be the material corresponding to the second adhesive layer 8, such as polyurethane resin, but not limited thereto. The heat sealing layer 9 may be a polyethylene film, but not limited thereto.

[0072] S3, forming the first bonding layer 4 and the insulating layer 3

[0073] The adhesive layer material is coated on the first anti-oxidation layer 5, and after drying, it is thermally bonded to the insulating layer 3 film to form the first adhesive layer 4 and the insulating layer 3 on the first surface.

[0074] Specifically, the material of the adhesive layer may be the material corresponding to the first adhesive layer 4, such as polyurethane resin, but not limited thereto. The insulating layer 3 may be a polyethylene terephthalate film, but not limited thereto.

[0075] In some embodiments, the method further comprises: after forming the first adhesive layer 4 and the insulating layer 3, performing an aging treatment at 40°C-85°C for 72h-144h, and then coating a slip agent on the insulating layer 3 or the heat-sealing layer 9 to form a slip layer. Specifically, the aging temperature may be 40°C, 50°C, 60°C, 70°C, 80°C, 85°C, etc., and the aging treatment time may be 72h, 80h, 90h, 100h, 110h, 120h, 130h, 140h, 144h, etc.

[0076] Specifically, the coating method of each layer is not limited, for example, a composite film can be formed by using micro-concave coating or dry composite molding process.

[0077] An embodiment of the present invention also provides a battery thermal insulation sheet, comprising a thermal insulation sheet and a packaging film for packaging the thermal insulation sheet. The packaging film is the packaging film for the above-mentioned battery thermal insulation sheet. By improving the packaging film, the service life of the battery thermal insulation sheet can be further improved and the performance of the battery thermal insulation sheet can be made more stable.

[0078] In some embodiments, the thermal insulation sheet contains phase change material. The packaging film provided by the embodiment of the present invention is particularly suitable for the phase change material thermal insulation sheet, can effectively block water and oxygen, and has a certain burst strength.

[0079] The embodiment of the present invention further provides a secondary battery, comprising the above-mentioned battery heat insulation sheet, which can improve the thermal stability of the battery and improve the safety performance of the battery.

[0080] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0081] It should be noted that the preparation process of the following examples and comparative examples is as follows: (1) Provide a barrier layer material, coat the anti-oxidation material on both sides of the barrier layer material, dry it, coat it with an adhesive material, and thermally bond it with a heat-sealing layer tape (the bonding temperature is 90° C.) to obtain a semi-finished product A. (2) Coat the adhesive layer material on the other side of the barrier layer on the semi-finished product A, dry it, and thermally bond it with an insulating layer tape (the bonding temperature is 90° C.) to obtain a semi-finished product B. (3) Put the semi-finished product B into an oven for aging, then take it out to obtain a semi-finished product C, and control the aging temperature to be 60° C. and the aging time to be 144 h.

[0082] When the product also contains a slippery layer, the following steps are also included: coating a slippery agent on the heat-sealing layer of the semi-finished product C, with a coating amount of 15 mg / m 2 , and after drying, semi-finished product D is obtained.

[0083] Example 1

[0084] This embodiment provides a packaging film for packaging a heat insulation sheet, and its structure is as follows:

[0085] Insulation layer (15 μm);

[0086] First adhesive layer (4-5 μm);

[0087] Barrier layer (35 μm);

[0088] Second adhesive layer (4-5 μm);

[0089] Heat seal layer (30μm)

[0090] Slippery layer (0.01μm).

[0091] Among them, the barrier layer is aluminum foil; the insulating layer is a polyimide film (purchased from Suzhou Kechuan Electronics Co., Ltd. with model number PI12); the adhesive layer (the first adhesive layer and the second adhesive layer, the same below) is a polyurethane resin (purchased from Suzhou Mingguan Co., Ltd. with model number T146); the heat sealing layer is a single-layer polypropylene film (purchased from Zhangjiagang Kangdexin Co., Ltd. with model number 1030) with a melting point of 145°C; and the slippery layer is erucamide.

[0092] Example 2

[0093] This embodiment provides a packaging film for packaging a heat insulation sheet, which is different from the embodiment 1 only in that the insulating layer is made of nylon 6 film (purchased from Changsu Company with the model number PHA).

[0094] Example 3

[0095] The only difference from Example 1 is that the thickness of the insulating layer is 25 μm.

[0096] The voltage breakdown resistance of the packaging film was obtained by testing Examples 1-3, and the results are shown in Table 1. Voltage breakdown resistance test method: refer to GB / T 31034-2014.

[0097] Table 1 Comparison of voltage breakdown resistance of different materials

[0098] Serial number project Example 1 Example 2 Example 3 1 Breakdown voltage KV 9.7 7.4 12.8

[0099] As shown in Table 1, polyimide has the best breakdown resistance. However, the thickness has a great influence, and when the film thickness increases, the breakdown voltage increases greatly.

[0100] Example 4

[0101] This embodiment provides a packaging film for packaging a heat insulation sheet, and its structure is as follows:

[0102] Insulation layer (15 μm);

[0103] First adhesive layer (4-5 μm);

[0104] Barrier layer (35 μm);

[0105] Second adhesive layer (4-5 μm);

[0106] Heat seal layer (30μm)

[0107] Slippery layer (0.01μm).

[0108] Among them, the barrier layer is aluminum foil; the insulating layer is polyethylene terephthalate film; the adhesive layer (the first adhesive layer and the second adhesive layer, the same below) is polyurethane resin; the heat sealing layer is a single-layer polypropylene film (purchased from Zhangjiagang Kangdexin Company, model 1030), with a melting point of 145°C; and the slip layer is erucamide.

[0109] Example 5

[0110] The only difference from Example 4 is that the heat sealing layer is a single-layer polyethylene film (purchased from Mingguan Company, model BO) with a melting point of 120°C.

[0111] Example 6

[0112] The only difference from Example 4 is that the heat sealing layer is a three-layer polyethylene film with a melting point combination of 120°C / 130°C / 120°C and a layer thickness ratio of 1:1:1.

[0113] Example 7

[0114] The only difference from Example 4 is that the heat sealing layer is a three-layer polypropylene film with a melting point combination of 145°C / 163°C / 145°C and a layer thickness ratio of 1:1:1.

[0115] Example 8

[0116] The only difference from Example 4 is that the heat sealing layer has a thickness of 80 μm, the heat sealing layer is a three-layer polypropylene film with a melting point of 145° C. / 163° C. / 145° C. and a layer thickness ratio of 1:1:1.

[0117] The effects of Examples 4-8 on heat seal peel force were tested, and the results are shown in Table 2. Test method for the effect on heat seal peel force: refer to T / CIAPS0005018-2018.

[0118] Table 2 Effect of different heat seal materials on heat seal peeling force

[0119]

[0120] Table 2 shows that for different materials with the same thickness and the same structure, the heat-sealing peeling force of polypropylene is higher than that of polyethylene, and the heat-sealing film of a single-layer structure is higher than that of a multi-layer structure. However, the sol uniformity of the multi-layer structure is better, while the single layer is easy to break. In addition, under the same structure, the thicker the heat-sealing layer, the lower the peeling force.

[0121] Example 9

[0122] This embodiment provides a packaging film for packaging a heat insulation sheet, and its structure is as follows:

[0123] Insulation layer (15 μm);

[0124] First adhesive layer (4-5 μm);

[0125] Barrier layer (35 μm);

[0126] Second adhesive layer (4-5 μm);

[0127] Heat seal layer (30 μm);

[0128] Slippery layer (0.01μm).

[0129] Among them, the barrier layer is aluminum foil; the insulating layer is polyethylene terephthalate film; the adhesive layer is polyurethane resin (purchased from Suzhou Mingguan Company, model T146); the heat sealing layer is a three-layer polypropylene film with a melting point of 145℃ / 163℃ / 145℃ and a layer thickness ratio of 1:1:1; the slippery layer is erucamide.

[0130] Example 10

[0131] The only difference from Example 9 is that: a first anti-oxidation layer and a second anti-oxidation layer are added; the anti-oxidation layers (the first anti-oxidation layer and the second anti-oxidation layer, the same below) are chromium nitrate, and the chromium content is 106 ppm.

[0132] Insulation layer (15 μm);

[0133] First adhesive layer (4-5 μm);

[0134] First anti-oxidation layer (0.01μm)

[0135] Barrier layer (35 μm);

[0136] Second anti-oxidation layer (0.01μm)

[0137] Second adhesive layer (4-5 μm);

[0138] Heat seal layer (30 μm);

[0139] Slippery layer (0.01μm).

[0140] The aging lifespans of Example 9, Example 10 and Example 3 were tested, and the results are shown in Table 3.

[0141] Table 3 Effect of anti-oxidation layer on aging life

[0142] Serial number project Example 9 Example 10 Example 3 1 Double 85 high temperature and high humidity aging (layering days) 6 18 9

[0143] As shown in Table 3, by comparing Examples 9 and 10, it can be seen that the anti-oxidation layer has a great influence on the life of the product, and the life of the product with the anti-oxidation layer is much longer than that without the anti-oxidation layer. At the same time, under the same conditions, the thicker the PET, the better the aging high temperature and high humidity performance.

[0144] Embodiment 11

[0145] The only difference from Example 10 is that no slip layer is provided, that is, no slip agent coating treatment is performed after aging.

[0146] The tensile properties of Example 10, Example 11, Example 3 and Example 8 were tested, and the results are shown in Table 4. The test method refers to T / CIAPS0005018-2018.

[0147] Table 4 Effect of lubricant on tensile properties and layer thickness on tensile properties

[0148] Serial number project Example 10 Embodiment 11 Example 3 Example 8 1 Punching depth (mm) 4 2 5 4 2 Punching and rolling condition No curling No curling Rolling the insulation layer Rolling to the heat seal layer

[0149] As shown in Table 4, by comparing Examples 10 and 11, it can be seen that the application of the lubricant has an obvious positive effect on the punch shell. At the same time, the thicker the insulation layer is, the more conducive it is to stretching, but it will curl, which is not conducive to process production.

[0150] In addition, increasing the thickness of the heat-sealing layer will have no effect on tensile strength, but will cause thermal stratification and curling, so the thickness control of each layer will affect the curling and tensile properties of the product.

[0151] Comparative Example 1

[0152] This comparative example provides a traditional heat insulation film packaging film (purchased from Zhejiang Yangu Technology Co., Ltd., model number YGBZ80)), whose structure is as follows Figure 1 The insulating layer 1 and the hot melt adhesive 2 are shown. The insulating layer 1 is made of polyethylene terephthalate with a thickness of 50 μm. The hot melt adhesive 2 is made of polypropylene with a thickness of 30 μm and is formed by online lamination.

[0153] The barrier properties of Example 10 and Comparative Example 1 were tested, and the results are shown in Table 5. The test method is based on GB / T 21529-2008

[0154] Table 5 Barrier properties of traditional thermal insulation film packaging film and aluminum-containing packaging film

[0155] Serial number project Example 10 Comparative Example 1 1 Water vapor barrier(ppm) 0.52 173.43

[0156] As shown in Table 5, by comparing Example 10 with Comparative Example 1, it can be seen that the water vapor barrier performance of the conventional thermal insulation sheet is much weaker than that of the packaging film containing the aluminum layer. In particular, for the thermal insulation sheet of the phase change material, the conventional packaging film cannot meet the high water barrier requirements.

[0157] The breakdown voltage, packaging tensile force, shell punching performance, water vapor barrier performance and high temperature and high humidity double 85 performance of the test examples and comparative examples were compared, and the results are shown in Table 6.

[0158] The test method for high temperature and high humidity double 85 performance comparison refers to GB / T 37663.2-2019.

[0159] Table 6 Performance test results of embodiments and comparative examples

[0160]

[0161] Notes: ▲ means it is mainly impossible to test; ★ means the punching shell is flat; ● means the punching shell is curled; □ means the heat sealing sol is uniform; O means the heat sealing sol is irregular.

[0162] From the above examples, it can be seen that embodiment 10 has the best results.

[0163] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery thermal insulation sheet, characterized in that: A heat-insulating sheet and a packaging film for packaging the heat-insulating sheet, wherein the heat-insulating sheet contains a phase change material, and the packaging film comprises a barrier layer, wherein the barrier layer has a first surface and a second surface opposite to the first surface, wherein a first adhesive layer and an insulating layer are sequentially arranged on the first surface, and a second adhesive layer and a heat-sealing layer are sequentially arranged on the second surface; A first anti-oxidation layer is provided between the barrier layer and the first adhesive layer, and a second anti-oxidation layer is provided between the barrier layer and the second adhesive layer; the materials of the first anti-oxidation layer and the second anti-oxidation layer are independently selected from at least one of fluorocarbon resin, chromium nitrate, zinc nitrate, zinc oxide and modified polyolefin resin; A slippery layer is also formed on the heat-sealing layer, and the material of the slippery layer is selected from at least one of erucamide, oleamide, behenamide, ethylenebisoleamide and biserucamide; The barrier layer is selected from at least one of aluminum foil, aluminized film, copper foil, iron foil and steel foil; The material of the insulating layer is selected from at least one of polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polystyrene, polyamide, polyimide, polyethylene terephthalate and polyethylene naphthalate; The materials of the first adhesive layer and the second adhesive layer are independently selected from at least one of polyurethane resin, polyolefin resin, polyacrylic resin, hot melt adhesive, epoxy resin, urea-formaldehyde resin, phenolic resin and melamine-formaldehyde.

2. The battery heat insulation sheet according to claim 1, characterized in that: The thickness of the first anti-oxidation layer and the second anti-oxidation layer are both 0.01 μm-1.0 μm.

3. The battery heat insulation sheet according to claim 2, characterized in that: The first anti-oxidation layer and the second anti-oxidation layer are both made of chromium nitrate, and the chromium content is 80ppm-100ppm.

4. The battery heat insulation sheet according to claim 1, characterized in that: When the material of the barrier layer is selected from at least one of aluminum foil, copper foil, iron foil and steel foil, the thickness of the barrier layer is 10 μm-100 μm; When the material of the barrier layer is an aluminum-plated film, the thickness of the aluminum-plated layer is controlled to be 0.038 μm-1 μm.

5. The battery heat insulation sheet according to claim 4, characterized in that: The aluminum-plated film comprises a polyester film with a thickness of 12 μm-100 μm, and the aluminum-plated layer is arranged on both sides of the polyester film.

6. The battery heat insulation sheet according to claim 4, characterized in that: The barrier layer is an aluminum foil with a thickness of 20 μm-60 μm.

7. The battery thermal insulation sheet according to claim 1, characterized in that: The thickness of the first adhesive layer and the second adhesive layer are both 2 μm-10 μm.

8. The battery heat insulation sheet according to claim 7, characterized in that: The first adhesive layer and the second adhesive layer are both made of polyurethane resin and have a thickness of 4 μm-5 μm.

9. The battery thermal insulation sheet according to claim 1, characterized in that: The thickness of the insulating layer is 3 μm-100 μm.

10. The battery heat insulation sheet according to claim 9, characterized in that: The insulating layer is a polyethylene terephthalate film with a thickness of 3 μm-50 μm.

11. The battery heat insulation sheet according to claim 1, characterized in that: The material of the heat sealing layer is polyolefin resin.

12. The battery heat insulation sheet according to claim 11, characterized in that: The material of the heat-sealing layer is selected from at least one of polypropylene, polyethylene, poly-1-butene and poly-4-methyl-1-pentene.

13. The battery heat insulation sheet according to claim 12, characterized in that: The heat sealing layer is selected from at least one of a cast polypropylene film and a polyethylene film.

14. The battery heat insulation sheet according to claim 13, characterized in that: The thickness of the heat sealing layer is 10 μm-100 μm.

15. The battery heat insulation sheet according to claim 14, characterized in that: The thickness of the heat sealing layer is 20 μm-80 μm.

16. The battery heat insulation sheet according to claim 12, characterized in that: The heat sealing layer is a multi-layer structure.

17. The battery thermal insulation sheet according to claim 1, characterized in that: The material of the slippery layer is selected from at least one of erucamide and oleamide.

18. The battery heat insulation sheet according to claim 17, characterized in that: When preparing the slippery layer, the coating amount is controlled to be 10 mg / m 2 -20mg / m 2 .

19. The battery thermal insulation sheet according to claim 1, characterized in that: The preparation process of the packaging film includes: providing a barrier layer material, wherein the barrier layer material has a first surface and a second surface opposite to the first surface; A first anti-oxidation layer, a first adhesive layer and an insulating layer are sequentially formed on the first surface of the barrier layer material, and a second anti-oxidation layer, a second adhesive layer and a heat-sealing layer are sequentially formed on the second surface.

20. The battery heat insulation sheet according to claim 19, characterized in that: Firstly, coating the first surface and the second surface of the barrier layer material with an anti-oxidation layer material, and then drying to form the first anti-oxidation layer and the second anti-oxidation layer; Coating the adhesive layer material on the second anti-oxidation layer, drying and laminating the adhesive layer with the heat-sealing layer film, so as to form the second adhesive layer and the heat-sealing layer on the second surface; The adhesive layer material is coated on the first anti-oxidation layer, and after drying, the adhesive layer material is thermally bonded to the insulating layer film to form the first adhesive layer and the insulating layer on the first surface.

21. The battery heat insulation sheet according to claim 20, characterized in that: Also includes: After the first adhesive layer and the insulating layer are formed, an aging treatment is performed at 40° C. to 85° C. for 72 h to 144 h, and then a lubricant is coated on the insulating layer or the heat-sealing layer.

22. A secondary battery, characterized in that: A battery heat insulation sheet comprising the battery heat insulation sheet according to any one of claims 1 to 21.

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