Lithium battery is the power battery used in new energy vehicles at present. The power battery has high energy density and obvious heat generation during large rate charge and discharge, which is mainly caused by internal resistance and electrochemical polarization. The existing technology is mainly to cool it and ensure that the battery works at a stable temperature.
The best working temperature of lithium battery is 20~40℃. If the local temperature is higher than 80℃, it will run out of control and cause the battery to burn. Therefore, each power battery has its own set of heat pipe system.At present, there are many cooling methods studied, mainly including air cooling, liquid cooling, phase change material cooling and heat pipe cooling.
At present, the commercial lithium battery cooling technology is mainly air cooling and double circuit liquid cooling.Air cooling is forced convection heat transfer through natural wind. When the battery capacity increases, the heat dissipation effect is poor.Large capacity batteries are generally liquid cooled, which is mainly shared with the automobile air conditioning system. The coolant is cooled through the air conditioning system, and the coolant is circulated through the pump to cool the battery.This scheme is mainly concerned about the corrosivity of coolant and short circuit caused by liquid leakage.At present, glacier coolant LM-8 coolant has no corrosion and has corresponding applications in power batteries.
The cooling channel of power battery is characterized by large aspect ratio, and the width is generally less than 1mm, which belongs to the category of microchannel. The traditional automobile coolant is ethylene glycol solution, which has high viscosity and large thermal boundary layer, which is not conducive to microchannel heat exchange, and the temperature field in the battery is easy to be uneven, resulting in the decline of efficiency and life of the battery.LM-8 glacier coolant has large unit capacity and small viscosity change within – 40 ~ 40 ℃. It is especially suitable for the power battery of new energy vehicles used in the north. In the long-term low-temperature environment, it can ensure the circulation of coolant and the uniformity of flow field in the flow channel. Some dead corners can be recycled through injection, so that the temperature at each point during battery operation does not exceed the optimal temperature zone.Improve the efficiency and stability of the battery and provide favorable guarantee for the thermal management system of the battery.