How to heat the power battery, the core component of new energy electric vehicles?

The power battery is the core of electric vehicles, to withstand high temperature and waterproof and cold. Electric vehicles seem to drive, the previous time will think of the "core" (battery) out of the problem, that in the summer high temperature atmosphere, the power battery can withstand 40 degrees of high temperature?

How to give electric vehicle power battery heat? The working current of the power battery is large, the heat production is large, and the battery pack is in a relatively closed environment, which will cause the temperature of the battery to rise. This is because the electrolyte in the Lithium Battery, the electrolyte plays a charge conduction role inside the lithium battery, and the battery without electrolyte is unable to charge and discharge the battery.

Water cooling tube liquid thermal silicone film

Lithium Batteries are mostly composed of flammable and volatile non-aqueous solutions, and this component system has a higher specific energy and voltage output than the battery composed of aqueous electrolytes, which meets the higher energy requirements of users. As the non-aqueous electrolyte itself is flammable and volatile, it infiltrates inside the battery and forms the combustion source of the battery.

Therefore, the working temperature of the above two battery materials should not be higher than 60°C, but now the outdoor temperature is close to 40°C, and the battery itself generates a lot of heat, which will cause the working environment temperature of the battery to rise, and if there is thermal runaway, the situation will be very dangerous. To avoid becoming a "barbecue", it is particularly important to heat the battery.

Thermal Conductive Materials for Power Batteries

There are two types of battery pack heat dissipation, active and passive, and there is a big difference in efficiency between the two. The cost required for passive systems is lower and the measures taken are simpler. Active systems are more complex and require more additional power, but their thermal management is more efficient. The heat dissipation effect of different heat transfer media is different, air cooling and liquid cooling have their advantages and disadvantages.

The main advantages of using gas (air) as a heat transfer medium are: simple structure, light weight, effective ventilation when harmful gases are generated, and low cost; the disadvantages are: low heat transfer coefficient between the battery wall, slow cooling speed, and low efficiency. At present it is widely used. The main advantages of using liquid as the heat transfer medium are:

Thermal conductive silicone film for power battery

High heat transfer coefficient between the battery wall and the cooling speed; The disadvantages are: high sealing requirement, relatively large quality, complex maintenance and servicing, the need for water jacket, heat exchanger and other components, the structure is relatively complex. In the actual application of electric buses, due to the large capacity and volume of the battery pack, the power density is relatively low, so the air cooling scheme is mostly used. For ordinary Car Battery packs, the power density is much higher. Accordingly, its heat dissipation requirements will be higher, so the water cooling scheme is also more common.

Depending on the temperature measurement point and the requirements, different sensors are used in the battery pack structure. The temperature sensor is placed in a more representative location with a wide temperature range, such as the air inlet and outlet and the middle area of the battery pack. This is especially important at high and low temperatures and in areas where heat accumulation in the centre of the battery pack is high. This helps to control the temperature of the battery in a relatively safe environment to avoid overheating and overcharging.