Battery thermal management system -Lithium - Ion Battery Equipment

Talking about New Energy Vehicle Battery Thermal Management System -Lithium - Ion Battery Equipment

When it comes to pure electric vehicles, the biggest problem is probably the cruising range. Friends who drive new energy electric vehicles in the north know that the cruising range will be greatly reduced in winter. As a result, they did not dare to turn on the air conditioner for heating, so they could only endure the severe cold and shiver in the compartment. It directly leads to the extremely poor experience of new energy vehicles. To solve this problem, we have to rely on the battery management system. Today, the editor will talk to you about this topic.(Lithium - Ion Battery Equipment)

What is a battery management system

The important task of the battery management system is to ensure that the battery pack works within a safe range, supply the necessary information required for vehicle control, respond in time when an abnormality occurs, and determine the charging and discharging power of the battery according to the ambient temperature, battery status, and vehicle needs. wait. The important functions of BMS include battery parameter monitoring, battery state estimation, online fault diagnosis, charging control, automatic equalization, thermal management, etc.

The Importance of Thermal Management Systems

The heat-related problems of batteries are the key factors that determine their performance, safety, life and cost. First, the temperature level of a Li-ion battery directly affects its energy and power performance in use. When the temperature is low, the available capacity of the battery will rapidly decay. Charging the battery at an extremely low temperature (such as below 0°C) may cause instantaneous voltage overcharge, resulting in internal lithium precipitation and a short circuit. . Second, the heat-related issues of Li-ion batteries directly affect the safety of the batteries. Defects in the manufacturing process or improper operation during use may cause local overheating of the battery, which in turn causes a chain exothermic reaction, eventually causing serious thermal runaway events such as smoke, fire or even explosion, threatening the lives of vehicle drivers and passengers Safety. In addition, the operating or storage temperature of lithium-ion batteries affects their service life. The suitable temperature of the battery is about 10~30°C, too high or too low temperature will cause a rapid decay of battery life. The large-scale power lithium battery makes the ratio of its surface area to volume relatively smaller, and the internal heat of the battery is not easily dissipated, and problems such as uneven internal temperature and excessive local temperature rise are more likely to occur, thereby further accelerating battery attenuation and shortening battery life. increase the user's total cost of ownership.

The battery thermal management system is one of the key technologies to deal with the heat-related problems of the battery and ensure the performance, safety and life of the power lithium battery. Important functions of a thermal management system include:

1. Effective heat dissipation when the battery temperature is high to prevent thermal runaway accidents;

2. Preheat the battery when the battery temperature is low, increase the battery temperature, and ensure the charging and discharging performance and safety at low temperature;

3. Reduce the temperature difference in the battery pack, suppress the formation of local hot spots, prevent the battery from decaying too quickly at high temperature locations, and reduce the overall life of the battery pack.

The temperature environment in the battery pack (pACK) has a great impact on the reliability, life and performance of the battery cell. Therefore, it is particularly important to maintain the temperature in the pACK within a certain temperature range. This is mainly achieved by cooling and heating, and its cooling methods are mainly divided into three categories:

Air-cooling: Air-cooling is a heat dissipation method that uses low-temperature air as the medium and uses heat convection to reduce the temperature of the battery. It is divided into natural cooling and forced cooling (using fans, etc.). This technology uses natural wind or a fan to cool down the battery with the evaporator that comes with the car. The system has a simple structure and is easy to maintain. It was widely used in early electric passenger cars, such as Nissan Leaf, Kia Soul EV, etc. It is also widely adopted in current electric buses and electric logistics vehicles.



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