On board power lithium battery system -Lithium - Ion Battery Equipment

On board power lithium battery system -Lithium - Ion Battery Equipment

Electric vehicles, powered by electricity instead of fossil fuels, are the only long-term solution for future transportation. As the heart of electric vehicles, the power battery system can be successfully promoted only if it is fully understood. From the perspective of the development trend of the main on-board power battery of electric vehicles at home and abroad, this paper focuses on the analysis of the promising lithium-ion battery and its battery management system.

The unbalanced charging of lithium ion battery pack charger easily causes overcharge and discharge problems, which seriously damages its service life. This paper proposes a new charging mode of intelligent charger, which can make the battery pack charge safely and reliably, extend its service life, increase safety and reduce the use cost.(Lithium - Ion Battery Equipment)

On board lithium ion battery management system

As the "brain" of battery monitoring in electric vehicles, the battery management system (BMS) can monitor the remaining battery power in hybrid electric vehicles, predict the battery power intensity, and facilitate the understanding of the entire battery system and the control of the vehicle system.

In a pure electric vehicle, BMS has intelligent adjustment functions such as predicting the remaining battery power, predicting the driving range and fault diagnosis. BMS has a particularly obvious effect on lithium ion batteries, which can improve the service state of batteries, extend the service life of batteries, and increase battery safety. BMS will be the key technology for the development of electric vehicles in the future.

Power battery system, vehicle charger charging technology, electric vehicle charging technology

As shown in Figure 1, the data acquisition module in BMS measures the voltage, current and temperature of the battery pack, and then transmits the collected data to the thermal management module and the safety management module for data display. The thermal management module controls the temperature of the battery cell to ensure that the battery pack is within the optimal temperature range.

The safety management module judges the estimated results of voltage, current, temperature and state of charge (SOC) of the battery pack, sends out a fault alarm when a fault occurs, and takes emergency protection measures such as open circuit in a timely manner. The state estimation module estimates the SOC and the state of health (SOH) according to the collected battery state data.

At present, it is mainly SOC estimation, and SOH estimation technology is not yet mature. The energy management module controls the charging and discharging process of the battery, including the battery power balance management, to eliminate the problem of inconsistent power of each cell in the battery pack. The data communication module adopts CAN communication mode to realize the communication between BMS and on-board equipment and non on-board equipment.

The core functions of BMS are SOC estimation, balance management and thermal management. In addition, BMS also has other functions, such as charge and discharge management, pre charger charge management, etc. In the process of battery charging and discharging, it is necessary to manage according to the environmental state, battery state and other relevant parameters, and set the best charging and discharging curve of the battery, such as setting the charging current of the charger, the upper limit voltage value of the charger, the lower limit voltage value of the discharge, etc. The capacitive load in the high-voltage system circuit of electric vehicles is equivalent to short circuit at the moment of power on, so it is necessary to conduct charging management of the pre charger to prevent the transient current impact of high-voltage circuit power on.



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