CN-121983604-A - Lithium fluorocarbon battery capable of continuously discharging at high power and manufacturing method thereof

CN121983604ACN 121983604 ACN121983604 ACN 121983604ACN-121983604-A

Abstract

The invention belongs to the technical field of lithium primary batteries, and particularly discloses a lithium fluorocarbon battery pack capable of continuously discharging with high power and a manufacturing method thereof. The battery pack includes at least one unit cell composed of a plurality of unit cells, a battery case, and a sheet-shaped thermal management interlayer. The sheet thermal management interlayer is arranged between adjacent single cells in the single cells and/or between different single cells and/or between the single cells and the cell shell, and is made of a graphene skeleton phase change composite material, and is composed of a three-dimensional porous graphene network and composite phase change materials filled in pores of the network. The flexible interlayer with the high heat conduction and high heat storage functions is integrated, so that heat can be actively and rapidly absorbed and homogenized during high-power discharge, the temperature rise of a battery pack is effectively inhibited, local hot spots are eliminated, continuous and stable high-power output of the lithium carbon fluoride battery is realized, and the safety and reliability of a system are remarkably improved.

Inventors

ZHANG HONGMEI
CHEN SHAOMIN
XU XING
YUAN ZAIFANG
WANG GUOJIANG
YAO DEMING
WANG QINGJIE
YU HUA

Assignees

贵州梅岭电源有限公司

Dates

Publication Date: 20260505
Application Date: 20260210

Claims (10)

1. A lithium fluorocarbon battery capable of sustaining high power discharge, comprising at least two unit cells and a battery case, the unit cells comprising a plurality of unit cells and a unit case, characterized by further comprising: a sheet-shaped thermal management interlayer disposed between adjacent unit cells within the unit cells, and/or between different unit cells, and/or between the unit cells and the battery case; the flaky thermal management interlayer is mainly a flaky graphene skeleton phase-change composite material which is formed by a three-dimensional porous graphene network and composite phase-change materials filled in the network pores.
2. The lithium fluorocarbon battery of claim 1, wherein the thermal management interlayer is a multilayer composite flexible sheet, further comprising: a porous polymer interface layer covering upper and lower surfaces of the sheet-shaped thermal management interlayer; and the flexible sealing layer is coated on the periphery of the sheet.
3. The lithium fluorocarbon battery of claim 1 or 2, wherein the composite phase change material comprises a main phase change component having a phase change temperature of 50 ℃ to 90 ℃ and a thermally conductive reinforcing nanofiller.
4. The lithium fluorocarbon cell of claim 1, further filled with thermally conductive silicone grease between adjacent cells within the cell.
5. The lithium fluorocarbon battery of claim 1 in which the contact area of the sheet thermal management interlayer to the cell side is greater than 80%.
6. The lithium fluorocarbon cell of claim 1, wherein the sheet thermal management interlayer has an in-plane thermal conductivity of 15 or more W/(m-K) and a thickness of 0.5 mm to 10.0 mm.
7. The lithium fluorocarbon cell of claim 1, wherein the main phase change component in the composite phase change material is selected from at least one of high purity paraffin wax, fatty acid, or alkane eutectic mixture.
8. A method for manufacturing a lithium fluorocarbon battery capable of sustaining high power discharge according to any one of claims 1,2,4 to 7, comprising the steps of: (1) Preparing a graphene skeleton, namely taking graphene hydrogel with high concentration and uniform dispersion as a raw material, taking deionized water as a solvent, and stirring at a high speed of 2000-3000 r/min for 60-150 min to obtain uniform and stable diluted graphene hydrogel; (2) Immersing the graphene skeleton into the molten phase-change material, vacuumizing and degassing, pressurizing by introducing inert gas, filling the molten composite phase-change material into pores of the skeleton through vacuum impregnation, and carrying out hot-pressing reduction treatment to obtain the flaky material; (3) Cutting the sheet material obtained in the step (2), attaching the sheet material to the surface of the single battery, and assembling a plurality of single batteries and the sheet material into a unit shell together to form the unit battery; (4) The battery module is integrated, namely, at least two unit cells are assembled into the battery module through spacing and thermal connection of the sheet-shaped materials obtained in the step (2); (5) System integration, namely, the battery module is installed in a battery shell and packaged.
9. The method according to claim 8, wherein the hot press reduction treatment in step (2) is performed at a temperature of 150 to 250 ℃ and a pressure of 5 to 20 MPa.
10. The method according to claim 8, wherein in the step (2), the vacuum impregnation temperature is 90 to 120 ℃.

Description

Lithium fluorocarbon battery capable of continuously discharging at high power and manufacturing method thereof Technical Field The invention belongs to the technical field of lithium primary batteries, and particularly relates to a lithium fluorocarbon battery with excellent heat management capability and a manufacturing method thereof, which are particularly suitable for high-energy-density application scenes requiring long-time and large-current discharge. Background The lithium carbon fluoride battery has extremely high theoretical specific energy (about 2180 Wh/kg), is one of batteries with highest energy density in the current primary battery system, and has irreplaceable application in the special fields of spacecrafts, military equipment, medical implantation equipment, exploration instruments and the like. However, with the continuous increase of power demand of electric equipment, the lithium fluorocarbon battery is often required to be assembled into a battery pack in a multi-section serial or parallel manner to meet the voltage and capacity requirements. However, battery packs face more severe thermal challenges than cells when discharged at high power: 1. Heat accumulation effect, namely, heat generated by simultaneous heavy current discharge of a plurality of batteries is mutually overlapped to form serious heat accumulation in the battery pack; 2. And the heat distribution is uneven, so that the heat dissipation at the central position is difficult due to the structural limitation of the battery pack, and a temperature gradient is easy to form, so that the performances of all the single batteries are uneven, and the overall discharge capacity and the stability of a voltage platform are influenced. Local overheating may cause internal short circuits, with a risk of burning or explosion. 3. The thermal runaway propagation risk is that overheat of the single battery may cause temperature interlocking of adjacent batteries to rise, thereby increasing the safety risk; 4. power output decays-to prevent overheating, battery management systems often force limiting the discharge current or terminate the discharge prematurely, resulting in actual available power well below theoretical. 5. Performance decay, namely, high temperature accelerates electrolyte decomposition and irreversible side reaction of electrode materials, and seriously damages battery performance. In the prior art, battery pack thermal management mainly relies on external heat dissipation systems, such as air cooling, liquid cooling or phase change material wrapping. However, the methods have obvious defects that the volume, the weight and the energy consumption of an air cooling system and a liquid cooling system are increased, and the traditional phase change material (such as a paraffin plate) has low heat conductivity, is not adjustable in shape, is in poor contact with a battery, and cannot actively regulate and control the heat flow direction. Particularly for lithium fluorocarbon batteries, the heat generation in the discharge process has time non-uniformity, and dynamic matching is difficult to realize by the traditional heat dissipation scheme. Therefore, developing a novel thermal management structure capable of efficiently managing heat from inside and ensuring continuous high-power discharge of the battery pack becomes a key for promoting technical development of the lithium fluorocarbon battery pack. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a lithium fluorocarbon battery which is efficient in thermal management and can ensure continuous high-power discharge and a manufacturing method thereof. In order to achieve the purpose, the technical scheme is that the lithium fluorocarbon battery capable of continuously discharging with high power comprises at least two unit batteries and a battery shell, wherein the unit batteries comprise a plurality of unit batteries and the unit shell, and the lithium fluorocarbon battery further comprises: a sheet-shaped thermal management interlayer disposed between adjacent unit cells within the unit cells, and/or between different unit cells, and/or between the unit cells and the battery case; the flaky thermal management interlayer is mainly a flaky graphene skeleton phase-change composite material which is formed by a three-dimensional porous graphene network and composite phase-change materials filled in the network pores. Preferably, as an improvement, the thermal management interlayer is a multilayer composite flexible sheet, further comprising: The porous polymer interface layer is a hydrophobic modified porous polymer film, the porosity of the porous polymer interface layer is more than 50%, the thickness of the porous polymer interface layer is 10-50 mu m, and the porous polymer interface layer covers the upper surface and the lower surface of the sheet-shaped thermal management interlayer and i