Pulse discharge self-heating method and device for lithium ion battery

Abstract

The invention discloses a pulse discharge self-heating method and device for a lithium ion battery. The pulse discharge self-heating method comprises the following steps: collecting the initial temperature of the lithium ion battery; controlling the lithium ion battery to perform high-frequency pulse discharge according to the initial temperature; collecting the temperature of the discharged lithium ion battery to obtain a discharge temperature; and adjusting discharge current according to the discharge temperature so as to allow the lithium ion battery to undergo self-heating. According to the invention, self-heating of the battery is realized in virtue of high-frequency pulse discharge control; due to the existence of the internal resistance of the lithium ion battery and the mechanism of an electrochemical reaction, heat is generated during cyclic charging and discharging of the battery, and thus, the battery is heated from the inside and battery temperature is more uniform; therefore, the insufficiency that conventional lithium-ion battery systems cannot be used under low temperature conditions is overcome, hardware facilities needed in other external heating design methods areomitted, equipment cost is lowered, and the applicability of the battery under low temperature conditions is improved.

Description

technical field [0001] The invention relates to the field of lithium ion battery heating, in particular to a lithium ion battery pulse discharge self-heating method and device. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, large capacity, small size, light weight, and wide operating temperature range. Lithium-ion battery packs have been widely used in various fields, including electric bicycles, electric tools and electric vehicles. Lithium-ion batteries are more sensitive to the temperature of the operating environment. When the temperature is low, the dischargeable energy, power and discharge efficiency of the battery are low, and there are certain safety hazards when charging at low temperatures, such as the generation of dendrites. Therefore, the problem of low temperature use has greatly affected the application and promotion of lithium-ion batteries. [0003] Currently, there are three main options for use in cryogenic enviro...

AI Technical Summary

Problems solved by technology

(1) There is no heating system. During the use of this scheme, the discharge efficiency of the battery pack is relatively low, which seriously affects the power, service life and safety of the battery pack.

(2) It is designed to use external heating such as electric heating wire auxiliary heating. Due to the poor heat transfer performance of the battery itself, this solution has defects such as low efficiency and easy to cause uneven battery temperature.

The unevenness of the working temperature of the battery pack will have an impact on battery life, safety, etc.

(3) In the low-temperature environment of adding resistors inside the battery, an internal short circuit occurs inside the battery so that the battery temperature rises above zero in a short period of time. However, this design scheme has two disadvantages.

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