Polymer lithium ion battery

Abstract

The invention relates to a lithium ion secondary battery, in particular to a gel polymer lithium ion battery and a production method thereof. The polymer lithium ion battery comprises an anode and a cathode. The polymer lithium ion battery is characterized in that a separator is arranged between the anode and the cathode, and two gel electrolyte layers are respectively arranged between the separator and the anode and the cathode. The method includes the following steps: electrode plate production, polymer coating, electrical core assembly, electrolyte filling and formation. Low-cost, lithium electrolyte-free cellulose acetate butyrate or the mixture of cellulose acetate butyrates with different hydroxy contents or modified polymer based on the cellulose acetate butyrate and added with other groups is dissolved in a certain amount of solvent to prepare polymer solution, which is coated on the surfaces of the electrodes to become films. Under an appropriate temperature, electrolyte solvent swells the polymer layers on the surfaces of the electrodes, so that polymer electrolyte is formed, and under moderate pressure, uniform interfaces are formed between the electrodes and the separator.

Description

technical field [0001] The invention relates to a lithium ion secondary battery, in particular to a gel polymer lithium ion battery and a manufacturing method thereof. Background technique [0002] At present, compared with traditional liquid lithium-ion batteries, secondary polymer lithium-ion batteries are safer, have higher energy density, and are easy to manufacture to less than 3 mm, so they occupy an increasing share in the market. There are many manufacturing methods for secondary polymer lithium batteries, and one of the typical methods is a preparation method of a plasticized state polymer electrolyte (US Patent 5296318) published by Bell Communications Research Institute (BELLCORE, USA) in 1994. Although this method completes relatively few processes in the drying room in the entire manufacturing process, it requires extraction operations, and it is difficult to automate production. Another manufacturing method of gel electrolyte battery is to add a prepolymer (su...

AI Technical Summary

Problems solved by technology

But too many processes in the drying room increase the manufacturing cost of the battery

Moreover, when preparing gel electrolytes, the volatility of low boiling point solvents makes it extremely difficult to control the consistency of gel electrolytes containing low boiling point solvents during the coating process

If a high boiling point solvent is used to prepare the gel electrolyte, it will not only make it difficult to control the coating process of the gel electrolyte, but also lead to poor low temperature performance of the battery cell.

Some people use vinylidene fluoride and hexafluoropropylene (PVDF-HEP) as gel lithium-ion batteries, but the production cost is high, the cost performance of the lithium-ion batteries produced is lower, and the market competitiveness is weak

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