As the market for electric vehicles (e.g. electric cars, electric buses and electric trucks) continues to grow, the demands on the efficiency and lifetime of lithium-ion battery systems are constantly increasing.
Acceptance will only increase if the ranges of the vehicles increase significantly.
The performance of lithium-ion batteries is highly dependent on the correct maintenance of the cell temperature. Therefore, an effective thermal management system is crucial to achieve maximum performance when operating under different environmental conditions.
Primary influencing factors for battery thermal management systems
There are four primary influencing factors that should be the focus of an appropriate battery thermal management system:
- Cooling
- Heating
- Insulation
- Ventilation
These four primary factors, when properly combined, maximise the safety, life expectancy, available power and capacity of the battery.
Cooling of rechargeable Li-ion batteries
Due to the inherent inefficiencies of Li-ion battery systems, the cells of the batteries generate heat when they release energy. For safety and performance reasons, this heat must be conducted away from the system to prevent overheating, which can damage the cells.
Dr. Dietrich Müller GmbH supplies various ready-made solutions here, which are explained in the article "8 ready-made thermal management solutions". Gap fillers, heat conducting foils and gap pads are particularly preferred here.
Heating of rechargeable Li-ion batteries
Conversely, if the cell temperature falls below the desired temperature limit, performance is also compromised and the cells require an additional heat source.
Dr. Dietrich Müller GmbH supplies 4 different heating systems with which the desired and required heat output can be achieved.
The four heating systems for the rechargeable Li-ion batteries are as follows:
1. wire heaters - wire heating
2. PTC Heaters - PTC heater
3. polyimide film based heaters - polyimide film heaters
4. high performance paper based heaters - high temperature paper heaters
Insulation of rechargeable Li-ion batteries
The use of appropriate insulation materials helps to reduce temperature fluctuations within the battery pack when it is exposed to extreme weather conditions.
It also reduces the power required to maintain a constant and desirable internal temperature, which is necessary for optimum battery performance.
Battery thermal insulation materials are capable of performing the following functions:
- Thermal insulation of rechargeable Li-ion batteries.
- UL94 V0 - fire protection
- electrical insulation
- compressibility
- technical cleanliness
- Burst protection
Ventilation of rechargeable Li-ion batteries
A well-designed ventilation system serves two functions, to exhaust hazardous gases within the battery system and to support the cooling system. However, a venting system can also undermine the heating and insulation of the battery if it is not designed appropriately.
Dr. Dietrich Mueller GmbH's materials for the ventilation of rechargeable Li-ion batteries are permeable membrane materials that are formed into various contours.
We also manufacture membranes that include an installable frame. The membranes are often made of PTFE film.