CN-122000551-A - Multi-layer functional composite battery cell heat insulation sheet and preparation method thereof

CN122000551ACN 122000551 ACN122000551 ACN 122000551ACN-122000551-A

Abstract

A multi-layer functional composite battery cell heat-insulating sheet and a preparation method thereof relate to a battery cell heat-insulating sheet and a preparation method thereof. The invention aims to solve the technical problems that the traditional battery cell heat-insulating sheet cannot effectively resist thermal runaway instant explosive thermal shock and high-intensity radiant heat due to single structure and isolated function, and is easy to cause structural damage and immediate failure of heat-insulating function. The invention is provided with the symmetrical alternating structure of the fiber reinforced phase change layer, the reflecting layer and the heat insulating layer, the fiber reinforced phase change layer on the outermost layer resists explosion impact through the glass fiber cloth framework to prevent the brittle fracture of the internal aerogel, and meanwhile, the encapsulated phase change material can quickly absorb a large amount of latent heat to realize the integrated defense from mechanical protection to active heat buffering, thereby solving the fundamental problem of instant failure of functions caused by structural damage of the traditional heat insulating sheet under instant thermal shock. The invention integrates the cooperative defense functions of resisting mechanical impact, absorbing phase change latent heat, reflecting radiant heat and blocking heat conduction into the sample for the first time.

Inventors

LI WENJIE
HE FEI
LI MINGWEI
JIANG YAOXING
MU YUWEN
HE XIAODONG

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260508
Application Date: 20260209

Claims (10)

1. The multi-layer functional composite battery cell heat insulation sheet is characterized by comprising a first fiber reinforced phase change layer, a first reflecting layer, a first heat insulation layer, a second reflecting layer, a second heat insulation layer, a third reflecting layer and a second fiber reinforced phase change layer from top to bottom.
2. The multi-layer functional composite battery cell heat-insulating sheet according to claim 1, wherein the first fiber-reinforced phase-change layer and the second fiber-reinforced phase-change layer have the same structure and are composed of glass fiber cloth and an organic silicon resin-phase-change composite coating layer coated and cured on the glass fiber cloth.
3. The multi-layer functional composite battery cell heat-insulating sheet according to claim 2 is characterized in that the organic silicon resin-phase change composite coating comprises, by weight, 10-20 parts of organic silicon resin, 5-20 parts of epoxy resin, 1-5 parts of curing agent, 10-60 parts of phase change material and 40-60 parts of absolute ethyl alcohol.
4. The multi-layer functional composite battery cell heat-insulating sheet according to claim 3, wherein the phase change material is one or a mixture of a plurality of calcium chloride hexahydrate, magnesium chloride hexahydrate, sodium sulfate decahydrate, gypsum, sodium acetate and sodium polyacrylate.
5. The multi-layer functional composite battery cell heat-insulating sheet according to claim 1, wherein the first reflecting layer, the second reflecting layer and the third reflecting layer are all metal foils or vacuum metal plating films, and are made of one or a mixture of more of silver, aluminum, copper or steel.
6. The multi-layer functional composite battery cell heat-insulating sheet according to claim 1, wherein the first heat-insulating layer and the second heat-insulating layer are aerogel heat-insulating layers, and are made of silica aerogel, ceramic fiber felt or ceramic fiber paper.
7. The multi-layer functional composite battery cell heat insulation sheet according to claim 1 is characterized in that the thickness of the first heat insulation layer and the second heat insulation layer is 0.5 mm-1 mm, the thickness of the first fiber reinforced phase change layer and the second fiber reinforced phase change layer is 0.2 mm-0.4 mm, and the thickness of the first reflection layer, the second reflection layer and the third reflection layer is 0.0125 mm-0.015 mm.
8. The multi-layer functional composite battery cell heat-insulating sheet according to claim 1, wherein the outer side of the multi-layer functional composite battery cell heat-insulating sheet is further required to be coated and packaged by a packaging film, and the packaging film is a PET film, a PI film or an aluminum plastic film.
9. The method for preparing the multi-layer functional composite battery cell heat-insulating sheet according to claim 4, which is characterized by comprising the following steps: s1, preparing a composite layer preform, namely uniformly coating organic silicon resin-phase change composite slurry on the upper surface and the lower surface of glass fiber cloth, immediately attaching a reflecting layer on the surface of wet glass fiber cloth, and heating, drying and curing to obtain an integrally formed fiber reinforced phase change layer-reflecting layer preform; S2, stacking and assembling, namely alternately stacking the fiber reinforced phase change layer-reflecting layer prefabricated body, the first heat insulation layer, the second reflecting layer, the second heat insulation layer and the fiber reinforced phase change layer-reflecting layer prefabricated body according to the structural sequence to obtain a multi-layer structure; s3, integrally packaging, namely placing the stacked multilayer structure of the S2 into a packaging film, and tightly combining all layers through hot pressing or vacuum packaging to obtain the battery cell heat insulation sheet.
10. The method for preparing the multi-layer functional composite battery cell heat-insulating sheet according to claim 9, wherein the composite slurry coating in the step S1 adopts a coating mode of doctor blade coating, roller coating or slit extrusion.

Description

Multi-layer functional composite battery cell heat insulation sheet and preparation method thereof Technical Field The invention relates to a battery cell heat insulation sheet and a preparation method thereof. Background Along with the wide application of lithium ion batteries in new energy automobiles and energy storage fields, the chain type heat spreading safety problem caused by thermal runaway is increasingly severe, so that the arrangement of efficient heat insulation sheets between electric cores has become a key for improving the safety of battery systems. Currently, the technical development of battery cell heat insulation sheets mainly expands around the improvement of basic heat insulation performance. The prior art scheme is divided into three types, namely firstly, aerogel (such as silicon dioxide and ceramic fiber aerogel) is used as a core heat insulation material, static heat insulation is realized through the extremely low heat conductivity coefficient of the aerogel, secondly, a flame retardant layer (such as mica and glass fiber cloth) or a packaging layer (such as PET film) is compounded on the basis of a heat insulation core material so as to improve fire resistance and structural integrity, and thirdly, a phase change material is tried to be introduced, and the temperature rise is delayed through latent heat absorption. However, the above-mentioned prior art still has significant drawbacks, especially when dealing with extreme, dynamic, explosive thermal shocks generated instantaneously by thermal runaway, the single structural function being a common drawback, most solutions focus only on "insulation" in a single dimension. When the battery core explodes, the generated shock wave and high-speed jet flow can act on the surface of the heat insulation sheet at first, and the porous aerogel layer in the existing structure is extremely easy to crack and pulverize, so that the porous heat insulation structure depending on the existence of the porous heat insulation layer is instantaneously and physically damaged, and the heat insulation function is quickly disabled. In summary, the current design of the electric core heat-insulating sheet is mostly based on steady-state or slow-temperature-rising conditions, the single structure and the isolated functional layer of the electric core heat-insulating sheet are difficult to form an effective protection closed loop at the extreme moment of thermal runaway, and once the first physical defense line (impact resistance) is broken through, the subsequent heat-insulating and heat-absorbing functions are similar to dummy functions. Disclosure of Invention The invention provides a multi-layer functional composite battery cell heat-insulating sheet and a preparation method thereof, which aim to solve the technical problems that the conventional battery cell heat-insulating sheet cannot effectively resist thermal runaway instant explosive thermal shock and high-intensity radiant heat due to single structure and isolated function, and is easy to cause structural damage and immediate failure of a heat-insulating function. The multi-layer functional composite battery cell heat insulation sheet consists of a first fiber reinforced phase change layer, a first reflecting layer, a first heat insulation layer, a second reflecting layer, a second heat insulation layer, a third reflecting layer and a second fiber reinforced phase change layer from top to bottom. The preparation method of the multi-layer functional composite battery cell heat-insulating sheet comprises the following steps: s1, preparing a composite layer preform, namely uniformly coating organic silicon resin-phase change composite slurry on the upper surface and the lower surface of glass fiber cloth, immediately attaching a reflecting layer on the surface of wet glass fiber cloth, and heating, drying and curing to obtain an integrally formed fiber reinforced phase change layer-reflecting layer preform; S2, stacking and assembling, namely alternately stacking the fiber reinforced phase change layer-reflecting layer prefabricated body, the first heat insulation layer, the second reflecting layer, the second heat insulation layer and the fiber reinforced phase change layer-reflecting layer prefabricated body according to the structural sequence to obtain a multi-layer structure; s3, integrally packaging, namely placing the stacked multilayer structure of the S2 into a packaging film, and tightly combining all layers through hot pressing or vacuum packaging to obtain the battery cell heat insulation sheet. The invention provides a novel multi-layer functional composite battery cell heat-insulating sheet, wherein each layer structure can realize cooperative defense from mechanical impact resistance, latent heat absorption, barrier conduction to reflected radiant heat aiming at different stages and different heat transfer modes in thermal runaway chain reaction, so that the structural integrity and fu