Lithium battery high-temperature fixture formation technique

Abstract

The invention discloses a lithium battery high-temperature fixture formation technique. According to the lithium battery high-temperature fixture formation technique, a battery cell is clamped in a fixture cabinet; a formation fixture is heated; and a formation process is performed on the battery cell. The formation process of the battery cell includes the following steps that: the battery cell isarranged in the fixture cabinet; constant-current charging is performed, the battery cell is pressurized, so that gases generated inside the battery cell can be squeezed out; constant-current charging current, charging voltage and the pressure of the fixture cabinet are increased, so that gases generated inside the battery cell are further squeezed out; the constant-current charging current, charging voltage and the pressure of the fixture cabinet are further increased, so that the battery cell can be shaped; and the battery cell is taken out of the fixture cabinet so as to cool, and the formation process is completed. Compared with conventional high-temperature pressurization formation, the lithium battery high-temperature fixture formation technique of the invention can reduce the viscosity of an electrolyte, improve the conductivity of the electrolyte and improve the ion migration speed of a battery material during a formation process, thereby shortening formation time, and increasing the utilization rate of equipment, and can also improve the discharge rate performance of a battery without affecting the service life of the battery.

Description

technical field [0001] The invention belongs to a polymer lithium ion battery production process, in particular to a lithium battery high-temperature fixture formation process. Background technique [0002] In recent years, with the popularization of smart mobile terminals and the promotion of resources and environmental protection, lithium-ion batteries have been widely used in portable electronic products, power tools, energy storage, and electric vehicles. [0003] Lithium-ion batteries need to undergo a pre-charge formation process during the production process. The purpose of this process is to form a SEI passivation film on the surface of the pole piece to prevent further reaction between the electrolyte and the pole piece, resulting in irreversible battery capacity and gas Adverse conditions such as swelling. [0004] In the existing technology, components with low boiling points are selected in the formula of battery electrolyte, such as ethyl methyl carbonate EMC, ...

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Problems solved by technology

[0004] In the existing technology, components with low boiling points are selected in the formula of battery electrolyte, such as ethyl methyl carbonate EMC, ethylene carbonate EC and diethyl carbonate DEC, and the formation temperature is generally set at 35°C-65°C. It leads to high electrolyte viscosity, low conductivity and low ion migration speed of battery materials; although there are also some high-temperature pressurized chemical formation processes on the market, which can form SEI films more effectively, but due to the high price of equipment for realizing the process , leading to an increase in the cost of battery production, and the formation time needs to be further optimized; even if some processes can effectively shorten the formation time, the performance of the battery produced by it is degraded; Processes that affect battery performance

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