All-solid-state battery cell structure, preparation method thereof and all-solid-state battery cell group

Abstract

The invention provides an all-solid-state battery cell structure, a preparation method thereof and an all-solid-state battery cell group. The preparation method comprises the following steps: preparing a positive active layer by adopting a dry method, laminating and compounding the positive active layer and a positive current collector to obtain a positive plate, and sleeving the periphery of the positive active layer with an insulating ring to obtain a structure I; preparing electrolyte slurry, coating and drying to obtain an electrolyte diaphragm, attaching the electrolyte diaphragm to the positive electrode active layer of the structure I, and laminating and compounding with the structure I to obtain a structure II; preparing negative electrode slurry, coating and drying to obtain a negative electrode active layer, attaching the negative electrode active layer to the electrolyte diaphragm of the structure II, and laminating and compounding the negative electrode active layer with the structure II to obtain a structure III; and a negative current collector is laminated on the surface of the negative active layer of the structure III, and the all-solid-state battery cell structure is obtained after lamination and packaging. Through pre-lithiation in the assembly process, the first efficiency of the battery and the cycle performance of the battery using the silicon negative plate can be effectively improved, the preparation process is simplified, and the manufacturing efficiency and consistency are improved.

Description

technical field [0001] The invention belongs to the technical field of all-solid-state batteries, and relates to an all-solid-state battery structure, a preparation method thereof and an all-solid-state battery pack. Background technique [0002] The solid-state battery replaces the flammable organic liquid electrolyte with a non-flammable solid electrolyte, which greatly improves the safety of the battery system and achieves a simultaneous increase in energy density. Among all kinds of new battery systems, solid-state batteries are the next-generation technology closest to industrialization, which has become the consensus of the industry and the scientific community. Among them, the sulfide electrolyte has relatively high lithium ion conductivity. Mainly including thio-LISICON, Li 6 P.S. 5 Cl, Li 10 GeP 2 S 12 , Li 6 P.S. 5 Cl, Li 10 SnP 2 S 12 , Li 2 S-P 2 S 5 , Li 2 S-SiS 2 , Li 2 S-B 2 S 3 etc., the ionic conductivity at room temperature can reach 10 ...

AI Technical Summary

Problems solved by technology

[0004] The preparation process and operation of all-solid-state batteries in the glove box are complex, the production efficiency is low, and all-solid-state batteries are usually subjected to high pressure during testing or work, and the sulfide electrolyte membrane has poor shear resistance. Capacity all-solid-state cells (multi-layer laminates) are prone to edge micro-short circuits, and because the internal structure of the battery is usually that the area of ​​the negative electrode is larger than the area of ​​the positive electrode (the negative electrode current collector is larger than the positive electrode current collector), the extra negative electrode and electrolyte membrane area binding force Or the pressure is less than that of the composite part with the positive electrode, and the negative electrode current collector is larger than the positive electrode current collector, so the extra area will be powdered due to shear force and expansion and contraction during the charging and discharging process. If silicon-based negative electrodes are used together, the composition Generally, it is composed of sulfide electrolyte (ionic conductor), silicon material, conductive agent, graphite material or alloy, etc. The conductivity of silicon material itself is low. As an active material, when silicon inserts and extracts lithium during the charge / discharge cycle, the volume changes. Reaching 270-400%, the cycle life is poor. This volume expansion will lead to the crushing of silicon particles, repeated cracking of the pole piece during charging and discharging, and the separation of the pole piece coating from the copper current collector, followed by pulverization and attenuation, eventually leading to lithium Ion battery failure

In addition, the silicon negative plate has low first effect without lithium supplementation, which reduces the capacity of the battery. In addition, in order to reduce the cost and improve the overall performance of the battery, the research and development personnel use the positive plate prepared by the dry method on the solid-state battery to avoid practical solvents, but The preparation of batteries with dry-process positive electrodes and related components will bring a series of technical problems, and there are very few mature technologies. The safety, electrical performance and production capacity of the battery are reduced

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