From the perspective of commercial lithium-ion power battery systems, key core technologies include battery pack technology (integrated battery pack, thermal management, collision safety, electrical safety, etc.), battery management system (BMS) electromagnetic compatibility technology, and signal accuracy Measurement (such as cell voltage, current, etc.) technology, accurate estimation of battery state, battery balance control technology, etc.
The other key core components of BMS and battery systems, including sensors, controllers, actuators, and other components, are basically monopolized by powerhouses in automotive electronics technology (Germany, Japan, and the United States). At present, some domestic enterprises have successfully developed smart meters, which can replace foreign current, voltage, and insulation sensors. The primary factor affecting the promotion and application of electric vehicles is the safety and cost of use of lithium-ion power batteries. In addition to the further improvement of the safety, life and consistency of the battery body, battery modular technology, battery pack technology (integrated battery pack, Thermal management, collision safety, electrical safety, etc.) also have a significant gap with foreign countries. At present, the battery pack technology of international automobile companies is relatively mature, and domestic research units have carried out more in-depth research in BMS electromagnetic compatibility technology, accurate signal measurement technology, accurate battery state estimation, and battery balance control technology.
The research and development of key technologies for battery power management include comprehensive battery electrochemical models, electrical safety design, battery state estimation, balance management, fault diagnosis and calibration, and charging management. The key technology of battery thermal management and system research and development need to study the heat dissipation effect of different thermal management technologies based on the structural design of the battery pack and the calculation and analysis of battery heat production, and obtain a battery thermal management cooling solution with low cost, simple process, and strong safety and reliability. . The light weight of the battery structure needs to take the battery system and the related structure of the vehicle as the research object, consider the mutual coupling characteristics, and carry out the integrated optimization of structural vibration resistance, impact resistance and lightweight from two aspects of structural design optimization and material selection Design key technology research work. Optimize the design schemes of parts materials, structural design, connection, etc., in terms of battery safety, it is necessary to carry out the overall safety scheme design research of the battery system on the basis of electrical safety, mechanical safety and thermal safety, and carry out fault diagnosis and prediction for the battery system , Thermal safety monitoring, early warning and key technologies for prevention and control.
Lithium-ion battery electrolytes are generally mixed with high-dielectric constant cyclic carbonate and low-dielectric constant linear carbonate. Generally speaking, the electrolyte of lithium ion batteries should meet the requirements of high ionic conductivity (10-3~10-2S/cm), low electronic conductivity, wide electrochemical window (0~5V), and good thermal stability (-40~60℃) ) And other requirements. Lithium hexafluorophosphate and other new lithium salts, solvent purification, electrolyte preparation, and functional additives technology continue to advance. The current development direction is to further increase its working voltage and improve battery high and low temperature performance. Safe ionic liquid electrolytes and solid electrolytes are under development.