HIGH PERFORMANCE THERMAL CONDUCTIVE ADHESIVE

Power battery is the "heart" of new energy vehicles. The battery pack of new energy vehicle needs to work in harsh environment for a long time, which will shorten the service life of battery. The uneven distribution of temperature field in the battery box will cause the performance imbalance of each battery module. The thermal monitoring and thermal management of battery pack of new energy vehicles is directly related to the performance of the vehicle, which is of great significance to the safe operation of the vehicle. 

Battery thermal management system is a complete system to ensure that the battery pack works in the appropriate temperature range. The change of battery temperature will change the performance of battery. For example, at low temperature, the available capacity of the battery will be greatly reduced. If the temperature is too low, there may be instantaneous voltage overcharge, resulting in electrolyte precipitation in the battery and causing short circuit. The thermal management system needs to preheat the battery at low temperature to ensure the efficiency and safety of low-temperature charging and discharging. When the battery temperature rises after a long time of operation, it is necessary to rely on the thermal management system for effective heat dissipation and heat sharing, so as to avoid the local overheating of the battery pack and affect its life and safety.

As an important part of battery thermal management system, thermal conductive adhesive should not only have excellent heat conduction effect, but also adapt to different application requirements to ensure the normal operation of thermal management system. Different thermal bonding schemes are needed for different lithium battery structures

1. Cylindrical battery pack: multiple cylindrical batteries (such as the common 18650 battery) are installed and fixed in the bracket to form a battery module. The adhesive with both thermal conductivity and flame retardant performance is used to fix and seal the battery module and the external fireproof board. Sometimes, in order to further improve the heat transfer effect and protect the battery pack, it is necessary to pour the heat conduction potting adhesive with low specific gravity, good flame retardant and strong flexibility into the battery module.

Cylindrical battery pack

2. Soft package battery pack: the soft package battery pack is composed of multiple soft package batteries. Aluminum plates are usually used to isolate the soft package batteries one by one, and thermal conductive adhesive is used to bond and fix the soft package battery and aluminum plate. This type of thermal conductive adhesive requires good initial bonding strength and fast curing ability, so as to adapt to large-scale mechanized production. After curing, it also has good thermal conductivity and vibration filtering effect.

Soft pack battery pack

3. Square battery pack: it is composed of multiple square batteries, and the parts between square batteries, battery and module partition board or module side plate can be bonded and fixed with thermal conductive adhesive similar to soft package battery. The gap between the battery and the bottom plate is filled with thermal interface material, such as thermal conductive gasket or heat conducting gel, so that the heat of the battery pack can be effectively transmitted to the outside world, while slowing down vibration and impact, and protecting the normal operation of the battery.

Square battery pack

Battery thermal management of new energy vehicles is not only an important link that can not be ignored, but also a system engineering, which needs to consider many factors. In the design of thermal management, the proper thermal conductive bonding scheme should be selected according to the characteristics and application requirements of different batteries, so as to ensure the service life and operation safety of the battery.