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CN-122025961-A - Composite buffer structure for battery and preparation method and application thereof

CN122025961ACN 122025961 ACN122025961 ACN 122025961ACN-122025961-A

Abstract

The invention relates to the technical field of batteries, in particular to a composite buffer structure for a battery, and a preparation method and application thereof. A composite buffer structure for a battery comprises a polymer matrix layer and a reinforcing phase positioned in the polymer matrix layer, wherein the reinforcing phase comprises a shape memory alloy fiber layer, the shape memory alloy fiber layer is of a three-dimensional net structure, and the volume fraction of the shape memory alloy fiber layer in the composite buffer structure for the battery is 10% -60%. The composite buffer structure for the battery, provided by the invention, has the advantages that the polymer matrix layer is used as a continuous phase, the shape memory alloy fiber layers are used as reinforcing phases, the reinforcing phases are mutually staggered in the polymer matrix layer to form a three-dimensional network structure, and the shape memory alloy fiber layers with proper volume fraction can be adopted to actively adapt to the volume change of an electric core, so that the composite buffer structure shows superelasticity at the working temperature of the battery, provides high and stable restoring stress, and has excellent fatigue resistance, thereby effectively maintaining long-term stable contact of a battery interface.

Inventors

  • SUN QIYUE
  • ZHANG SONGFENG
  • LIU KAIBO
  • FANG CHENG

Assignees

  • 中国第一汽车股份有限公司

Dates

Publication Date
20260512
Application Date
20260209

Claims (10)

  1. 1. A composite buffer structure for a battery, comprising a polymer matrix layer and a reinforcing phase in the polymer matrix layer, wherein the reinforcing phase comprises a shape memory alloy fiber layer, and the shape memory alloy fiber layer has a three-dimensional network structure; The volume fraction of the shape memory alloy fiber layer in the composite buffer structure for the battery is 10% -60%.
  2. 2. The composite buffer structure for a battery according to claim 1, wherein the volume fraction of the shape memory alloy fiber layer in the composite buffer structure for a battery is 30% -60%.
  3. 3. The composite buffer structure for a battery according to claim 1, comprising at least one of the following conditions: (1) The austenite phase transition ending temperature Af of the shape memory alloy fiber layer is less than or equal to minus 30 ℃; (2) The shape memory alloy fiber layer comprises at least one of nickel-titanium-based alloy fiber, copper-based alloy fiber and iron-based alloy fiber; (3) The fiber diameter of the shape memory alloy fiber layer is 0.05-0.5 mm; (4) The shape memory alloy fiber layer comprises a woven mesh and/or a non-woven fabric.
  4. 4. The composite buffer structure for a battery of claim 1, wherein the polymer matrix layer comprises an elastomeric material; preferably, the elastomeric material comprises a thermoset elastomer and a thermoplastic elastomer; Preferably, the thermosetting elastomer comprises at least one of thermosetting polyurethane and silicone rubber, and preferably, the Shore D hardness of the polyurethane is 80-85; Preferably, the thermoplastic elastomer includes at least one of a thermoplastic polyurethane elastomer and a polyester-based elastomer.
  5. 5. The method for manufacturing a composite buffer structure for a battery according to any one of claims 1 to 4, comprising the steps of: carrying out first impregnation on the shape memory alloy fiber layer by adopting a material system containing a thermosetting elastomer precursor material, and then carrying out heat treatment; or respectively arranging thermoplastic elastomer layers on the two side surfaces of the shape memory alloy fiber layer to form a laminated body, and carrying out hot pressing treatment on the laminated body to enable the melt formed by the polymer layer to carry out second impregnation on the shape memory alloy fiber layer.
  6. 6. The method for producing a composite buffer structure for a battery according to claim 5, comprising at least one of the following conditions: (1) The material system of the thermosetting elastomer precursor material comprises polyurethane prepolymer and curing agent, or liquid silicone rubber; (2) The first impregnation comprises vacuum infusion or casting; (3) The temperature of the heat treatment is 60-180 ℃, and the time of the heat treatment is 2-5 hours; (4) The heat treatment is followed by a first cooling and a first demoulding.
  7. 7. The method for producing a composite buffer structure for a battery according to claim 5, comprising at least one of the following conditions: (1) The thermoplastic elastomer layer is a film layer or a powder layer of a thermoplastic elastomer; (2) The temperature of the hot pressing treatment is higher than the melting point of the polymer layer and lower than the phase transition temperature of the shape memory alloy fiber layer; (3) The temperature of the hot pressing treatment is 10-50 ℃ higher than the melting point of the polymer layer, the pressure of the hot pressing treatment is 0.5-10.0 MPa, and the time of the hot pressing treatment is 10-90 min; (6) The hot pressing treatment further comprises a second cooling and a second demoulding.
  8. 8. The method for manufacturing a composite buffer structure for a battery according to claim 5, wherein the surface of the shape memory alloy fiber layer is previously subjected to roughening treatment or chemical treatment.
  9. 9. A battery is characterized by comprising a plurality of battery core units, wherein a composite buffer structure is arranged between every two adjacent battery core units, and the composite buffer structure is prepared by the preparation method of the composite buffer structure for the battery according to any one of claims 1-4 or the composite buffer structure for the battery according to any one of claims 5-8.
  10. 10. A powered device comprising the battery of claim 9.

Description

Composite buffer structure for battery and preparation method and application thereof Technical Field The invention relates to the technical field of batteries, in particular to a composite buffer structure for a battery, and a preparation method and application thereof. Background In the charging and discharging process of the power battery, the battery cells expand and contract along with the battery cells, buffer pads are needed to be added between the battery cells, the buffer pads are compressed when the battery cells expand, the expansion between the battery cells is absorbed, the deformation of the battery cell structure is avoided, and when the battery cells contract, the buffer pads provide support through rebound, and the positions of the battery cells are fixed. Meanwhile, the buffer cushion provides the stacking supporting force for the electric core, and good contact of material interfaces in the electric core is guaranteed. With the development of semi-solid and solid-state batteries, the assembly pressure of the battery core is very high in order to ensure good contact between the battery core, electrolyte and current collector and maintain ionic conduction. The buffer cushion needs to provide stable supporting force along with the expansion and contraction cycle of the battery cell under the condition of bearing larger pressure for a long time, and the requirement on the mechanical performance of the buffer cushion is continuously improved. Currently, widely used cushioning materials mainly include rubber, foamed silica gel, and the like. These conventional materials have a significant stress relaxation phenomenon at high pressures, i.e., the internal stress of the material is gradually attenuated over time at constant strain, resulting in a decrease in the pressure maintenance capability on the cell. Meanwhile, under the long-term expansion and contraction cycle action of the battery core, the material is easy to generate plastic deformation, the fatigue resistance performance is reduced, the rebound resilience performance is weakened, sufficient supporting force cannot be continuously provided, and poor contact of a battery interface, increased internal resistance and shortened service life are finally caused. Therefore, developing a new buffer material that can adapt to the volume change of the battery cell, withstand high voltages and provide stable supporting force throughout the life cycle of the battery is a key technical problem in meeting the future battery performance requirements. In view of this, the present invention has been made. Disclosure of Invention An object of the present invention is to provide a composite buffer structure for a battery, which can actively adapt to volume change of a battery cell, exhibit superelasticity at a battery operating temperature, provide high and stable restoring stress, and have excellent fatigue resistance, thereby effectively maintaining long-term stable contact of a battery interface. Another object of the present invention is to provide a method for manufacturing a composite buffer structure for a battery. Another object of the present invention is to provide a battery. It is another object of the present invention to provide a powered device. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: a composite buffer structure for a battery comprises a polymer matrix layer and a reinforcing phase positioned in the polymer matrix layer, wherein the reinforcing phase comprises a shape memory alloy fiber layer, the shape memory alloy fiber layer is of a three-dimensional net structure, and the volume fraction of the shape memory alloy fiber layer in the composite buffer structure for the battery is 10% -60%. In some embodiments, the volume fraction of the shape memory alloy fiber layer in the composite buffer structure for a battery is 30% -60%. In some embodiments, the shape memory alloy fiber layer has an austenite phase transition end temperature Af of less than or equal to-30 ℃. In some embodiments, the shape memory alloy fiber layer includes at least one of nickel titanium based alloy fibers, copper based alloy fibers, and iron based alloy fibers. In some embodiments, the fiber diameter of the shape memory alloy fiber layer is 0.05-0.5 mm. In some embodiments, the shape memory alloy fiber layer comprises a woven mesh and/or a nonwoven fabric. In some embodiments, the polymer matrix layer comprises an elastomeric material. In some embodiments, the elastomeric material includes a thermoset elastomer and a thermoplastic elastomer. In some embodiments, the thermoset elastomer comprises at least one of a thermoset polyurethane and a silicone rubber. In some embodiments, the polyurethane has a shore D hardness of 80-85. In some embodiments, the thermoplastic elastomer comprises at least one of a thermoplastic polyurethane elastomer and a polyester-based elastomer. The preparat