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CN-122025733-A - Battery monomer and preparation method thereof, battery device, power utilization device and energy storage device

CN122025733ACN 122025733 ACN122025733 ACN 122025733ACN-122025733-A

Abstract

The application provides a battery monomer, a preparation method thereof, a battery device, an electricity utilization device and an energy storage device. The battery monomer comprises a positive plate, a composite electrolyte sheet and a Li-In alloy negative electrode, wherein the positive plate comprises a positive electrode material, the positive electrode material comprises a modified lithium iron phosphate material, the modified lithium iron phosphate material comprises lithium iron phosphate, a first alloy and a second alloy, the first alloy is doped In a crystal lattice of the lithium iron phosphate, the second alloy is coated on the surface of the lithium iron phosphate, the first alloy comprises indium tin bismuth alloy, and the second alloy comprises indium tin bismuth alloy. According to the application, the indium tin bismuth alloy is simultaneously acted on the lithium iron phosphate material in a double mode of lattice doping and surface cladding, so that the key technical bottlenecks of poor electronic conductivity, slow lithium ion diffusion rate, unstable interface in the circulation process and the like inherent to the lithium iron phosphate material are cooperatively solved.

Inventors

  • Bi Ruobing
  • MA YUJUN
  • SHI YUTAO

Assignees

  • 浙江晶科储能有限公司

Dates

Publication Date
20260512
Application Date
20260415

Claims (16)

  1. 1. The battery cell is characterized by comprising a positive plate, a composite electrolyte plate and a Li-In alloy negative electrode, wherein the positive plate comprises a positive electrode material, the positive electrode material comprises a modified lithium iron phosphate material, the modified lithium iron phosphate material comprises lithium iron phosphate, a first alloy and a second alloy, the first alloy is doped In a crystal lattice of the lithium iron phosphate, the second alloy is coated on the surface of the lithium iron phosphate, the first alloy comprises an indium-tin-bismuth alloy, and the second alloy comprises an indium-tin-bismuth alloy.
  2. 2. The battery cell of claim 1, wherein the mass ratio of the first alloy to the second alloy is 30% -50%, 50% -70%.
  3. 3. The battery cell of claim 1, wherein the total mass of the first alloy and the second alloy is 2.5-3.5% of the mass of the modified lithium iron phosphate material.
  4. 4. The battery cell according to any one of claims 1 to 3, wherein a mass ratio of In element, sn element and Bi element In the first alloy is 0.37 to 0.39:0.32 to 0.34:0.28 to 0.30, the first alloy includes an InBi phase and an InSn 4 phase, and a mass ratio of the InBi phase and the InSn 4 phase is 29:33 to 50:50.
  5. 5. The battery cell according to any one of claims 1 to 3, wherein a mass ratio of In element, sn element and Bi element In the second alloy is 0.37 to 0.39:0.32 to 0.34:0.28 to 0.30, the second alloy includes an InBi phase and an InSn 4 phase, and a mass ratio of the InBi phase and the InSn 4 phase is 29:33 to 50:50.
  6. 6. A method for preparing the battery cell according to any one of claims 1 to 5, comprising preparing a positive electrode material and preparing a positive electrode sheet comprising the positive electrode material, sequentially stacking and assembling the positive electrode sheet, a composite electrolyte sheet and a Li-In alloy negative electrode to obtain the battery cell, wherein the positive electrode material comprises a modified lithium iron phosphate material, and the method for preparing the modified lithium iron phosphate material comprises the following steps: step S1, mixing and drying raw materials comprising a lithium source, an iron source, a phosphorus source, a solvent and an indium-tin-bismuth alloy to obtain a precursor; And S2, sintering the precursor in a first inert atmosphere to obtain the modified lithium iron phosphate material.
  7. 7. The method for preparing a battery cell according to claim 6, wherein the step S1 comprises: mixing raw materials comprising the lithium source, the iron source, the phosphorus source and the solvent to obtain slurry; mixing the slurry with the indium tin bismuth alloy, and drying to obtain the precursor; Wherein the mass of the indium-tin-bismuth alloy is 2.5-3.5% of the mass of the slurry; and/or the average grain diameter of the indium tin bismuth alloy is 50-100 nm.
  8. 8. The method for preparing a battery cell according to claim 6, wherein the preparation process of the indium-tin-bismuth alloy comprises: In a second inert atmosphere, melting and ball-milling raw materials comprising In powder, sn powder and Bi powder according to an atomic ratio to obtain the indium-tin-bismuth alloy, wherein the melting temperature is 150-200 ℃, and the melting time is 30-60 min; And/or the second inert atmosphere is selected from any one or more of Ar, N 2 and He.
  9. 9. The method according to claim 6, wherein in the step S1, the first inert atmosphere is selected from any one or more of Ar, N 2 , and He; and/or the lithium source is selected from one or more of Li 2 CO 3 、LiOH、LiNO 3 、LiCH 3 COO、LiH 2 PO 4 ; and/or, the iron source is selected from one or more of FeC 2 O 4 ·2H 2 O、Fe 2 O 3 、Fe 3 O 4 、Fe(NO 3 ) 3 、FeSO 4 ; and/or, the phosphorus source is selected from one or more of (NH 4 ) 2 HPO 4 、NH 4 H 2 PO 4 、H 3 PO 4 、LiH 2 PO 4 、P 2 O 5 ; and/or the solvent is selected from any one or more of water, ethanol, glycol and NMP.
  10. 10. The method for preparing a battery cell according to claim 6, wherein in the step S1, ultrasound is performed in the mixing process, the frequency of the ultrasound is 20-80 khz, and the time of the ultrasound is 1.5-2.5 h; and/or the drying temperature is 70-90 ℃, and the drying time is 10-14 h.
  11. 11. The method of manufacturing a battery cell according to claim 6, wherein in the step S2, the sintering includes a first sintering and a second sintering that are sequentially performed, the second sintering having a temperature higher than that of the first sintering; And/or the temperature of the first sintering is 300-400 ℃, and the time of the first sintering is 2-3 hours; and/or the temperature of the second sintering is 650-750 ℃, and the time of the second sintering is 5-7 h.
  12. 12. The method for producing a battery cell according to claim 6, further comprising a production process of the composite electrolyte sheet, the production process comprising: mixing raw materials comprising LiPSCl, liPO 3 and an organic solvent, and sequentially grinding and calcining to obtain the composite electrolyte; wherein the mass ratio of LiPSCl to LiPO 3 is 7:3-8:2; and/or the organic solvent is selected from any one or more of ethanol, glycol and NMP.
  13. 13. The method for producing a battery cell according to claim 12, wherein the calcination is performed in a third inert atmosphere selected from any one or more of Ar, N 2 , and He; And/or the calcining temperature is 500-600 ℃, and the calcining time is 3-4 h.
  14. 14. A battery device, characterized in that the battery device comprises the battery cell of any one of claims 1 to 5, and the battery device comprises one or more of a battery module, a battery pack and an energy storage battery.
  15. 15. An electric power consumption device, characterized in that it comprises the battery device according to claim 14, the battery device is used for providing electric energy.
  16. 16. An energy storage device comprising the battery device of claim 14 for storing electrical energy.

Description

Battery monomer and preparation method thereof, battery device, power utilization device and energy storage device Technical Field The invention relates to the technical field of battery preparation, in particular to a battery monomer and a preparation method thereof, a battery device, an electricity utilization device and an energy storage device. Background At present, the lithium iron phosphate (LFP) positive electrode material is widely applied to the field of lithium ion batteries due to the advantages of high safety, long cycle life, low cost and the like. However, the problems of low intrinsic electron conductivity, slow lithium ion diffusion rate, poor electrode/electrolyte interface stability, etc. severely restrict the application of the lithium ion battery in high-power, low-temperature and solid-state battery scenarios. In order to improve the performance, the prior art adopts strategies such as carbon coating, single metal element (such as Ti, mg and Zr) doping or binary alloy (such as Sn-Bi and Sn-Cu) surface modification. The carbon coating can improve the electron conductivity, but can reduce the tap density of an electrode and sacrifice the volume energy density, single metal doping is easy to cause lattice distortion to lead to capacity attenuation, binary alloy modification improves the conductivity to a certain extent, but is difficult to simultaneously realize the cooperative optimization of electron conduction, ion transmission and interface stress buffering, and especially in a solid-state battery system, interface peeling and rapid impedance rising are easy to be caused by poor interface contact and volume expansion in the circulation process, so that the battery performance is further deteriorated. In the above technology, the existing modification means cannot effectively construct a multifunctional composite interface structure with high electron conductivity, high ion mobility and good mechanical flexibility, and especially lacks a novel alloy system which can cooperate with lithium iron phosphate crystal lattices and form stable ion transmission channels. In addition, the prior art is limited to a single modification mode (such as doping or cladding only), so that the synergy of bulk phase strengthening and surface protection is difficult to realize, and key bottlenecks such as large polarization, poor circulation stability, insufficient rate performance and the like still commonly exist under the conditions of high-rate charge and discharge, low-temperature environment and solid-state battery assembly of materials, and the material requirements of the next-generation high-energy-density and high-safety solid-state lithium ion batteries are difficult to meet. Disclosure of Invention The invention mainly aims to provide a battery monomer, a preparation method thereof, a battery device, an electric device and an energy storage device, so as to solve the problems of low electronic conductivity, low ion diffusion rate and poor interface stability of a lithium iron phosphate anode material in the prior art. In order to achieve the above object, according to one aspect of the present invention, there is provided a battery cell including a positive electrode sheet, a composite electrolyte sheet, and a Li-In alloy negative electrode, the positive electrode sheet including a positive electrode material including a modified lithium iron phosphate material including lithium iron phosphate, a first alloy doped In a crystal lattice of the lithium iron phosphate, and a second alloy coated on a surface of the lithium iron phosphate, the first alloy including indium-tin-bismuth alloy, the second alloy including indium-tin-bismuth alloy. Further, the mass ratio of the first alloy to the second alloy is 30% -50%, 50% -70%. Further, the total mass of the first alloy and the second alloy accounts for 2.5-3.5% of the mass of the modified lithium iron phosphate material. Further, the mass ratio of In element, sn element and Bi element In the first alloy is 0.37-0.39:0.32-0.34:0.28-0.30, the first alloy comprises an InBi phase and an InSn 4 phase, and the mass ratio of the InBi phase to the InSn 4 phase is 29:33-50:50. Further, the mass ratio of In element, sn element and Bi element In the second alloy is 0.37-0.39:0.32-0.34:0.28-0.30, the second alloy comprises InBi phase and InSn 4 phase, and the mass ratio of InBi phase to InSn 4 phase is 29:33-50:50. In order to achieve the above object, according to another aspect of the present invention, there is provided a method for preparing the aforementioned battery cell, comprising preparing a positive electrode material and preparing a positive electrode sheet including the positive electrode material, sequentially stacking and assembling the positive electrode sheet, the composite electrolyte sheet and the Li-In alloy negative electrode to obtain the battery cell, wherein the positive electrode material includes a modified lithium iron phosphate materia