Preparation method of polymer lithium ion battery and polymer lithium ion battery

Abstract

The invention discloses a preparation method of a polymer lithium ion battery and the polymer lithium ion battery. The preparation method comprises the following steps of: preparing a positive plate and a negative plate which contains a silicon carbon active layer; coating a layer of polymer film on the two surfaces of the positive plate and the negative plate; arranging a diaphragm in the middle of the positive plate and the negative plate so that the positive plate, the diaphragm and the negative plate are prepared into a bare battery cell, and packaging the bare battery cell into the battery shell; injecting liquid electrolyte into the battery shell in a drying room, and sealing the opening of the battery shell to obtain a polymer lithium ion battery precursor; heating and pressurizing the polymer lithium ion battery precursor, and plasticizing to form the polymer lithium ion battery; and performing formation on the polymer lithium ion battery. The volume energy density of the polymer lithium ion battery is improved, the phenomenon that the silicon carbon active layer is powdered or drops from a negative current collector in the process of charging and discharging the negative plate which contains the silicon carbon active layer in the polymer lithium ion battery is avoided, and the cycle performance of the battery is improved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method for manufacturing a polymer lithium ion battery and the polymer lithium ion battery. Background technique [0002] Due to the characteristics of high voltage, no memory effect and high volumetric energy density, lithium-ion batteries have been widely used in portable appliances (smart phones, laptops, etc.). With the development of smart phones, the requirements for lithium-ion batteries are getting higher and higher, especially for the safety and volumetric energy density of lithium-ion batteries. [0003] In terms of improving the safety of lithium-ion batteries, polymer lithium-ion batteries are currently used. Because it does not have the problem of liquid leakage, and can inhibit the side reaction between the electrolyte solvent and the positive and negative electrodes of the battery, the safety of the polymer lithium-ion battery has been greatly improved. [00...

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Problems solved by technology

[0005] Although silicon resources are abundant in nature, it can be used as a new type of negative electrode material for polymer lithium-ion batteries with great development prospects, but when silicon is used as the negative electrode active material of polymer lithium-ion batteries, silicon is in the intercalation / delithiation process. During the process, there will be a huge volume change (the change rate exceeds 300%). Due to its huge volume change, the structure of the negative electrode active material of the polymer lithium-ion battery will collapse rapidly, pulverize or fall off from the negative electrode collector, resulting in electrons Can not be transferred quickly, so that the electrochemical performance of the negative electrode active material of the polymer lithium-ion battery drops sharply, thus affecting the overall performance of the polymer lithium-ion battery

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