Hybrid and Electric Vehicle Thermal Management
Battery Thermal Management and Inverter Cooling – IGBT (Insulated Gate Bipolar Transistor)
Temperature management is crucial to the success of hybrid and electric vehicles. Heat is created when either charging or discharging batteries which can lead to reduced life or catastrophic failure at high temperatures. Heat is generated from the internal resistance of the battery which is called Joule or Ohmic heating. Consistent cooling across battery cooling plates is one method to manage these temperatures.
Inverters, specifically the IGBTs (Insulated Gate Bipolar Transistors) transfer power between the motors and batteries. Cooling of IGBT’s also has become critical in maintaining reliability and efficiency. As an OEM supplier to many well-known vehicle manufactures, we have been working on these new thermal management challenges with our customers. This EV industry head start was gained by applying our extensive thermal management experience from gas and diesel power train systems. Our customers also have the advantage of working with an established industry partner that offers complete engineering, in house testing and large global production capabilities.
Battery Thermal Management
The current generation of electric vehicle batteries needs to be managed effectively. The current standard is to use liquid cooling. These water-glycol coolants can either be passed in between cells, battery packages or even through a cooling plate to manage the heat being generated. Typical cooling plate designs have a large temperature gradient across the heat exchanger surface offering inconsistent battery cooling. In contrast, our unique two pass battery cooling plate design provides a maximum of 3°C degree delta across the entire contact surface.
Power Inverters and IGBTs (insulated gate bipolar transistors)
Electric vehicles demand high efficiency and performance. The power inverter is one of the critical components in an electric vehicle. The inverter converts DC to AC when power is required to drive the electric motors, and converts in the opposite direction during regenerative braking. The main component inside the inverter is the IGBT (insulated gate bipolar transistor), and it generates heat. An effective method of cooling the IGBT is through a liquid cooled heatsink.
The IGBT heatsink is made up of a base plate, cover plate, and fin. Coolant enters through a spigot in the cover plate and then flows across the fin and exits through the spigot on the opposite side. The base plate sits on top of the IGBT to allow for surface contact cooling.
Increasing the heatsinks ability to transfer heat is important to achieve the increasing demands for reducing size and increasing current of the IGBT.
Senior Flexonics’ “Omega Fin” design was created in order to solve the challenge of increasing the performance of the heatsink while maintaining a minimum gap for particle size. The Omega fin works by increasing the amount of fin surface area inside the heatsink.
Omega Fin Design Benefits
- Developed to increase performance
while maintaining a minimum gap for
- More surface area can be utilized
with the Omega fin
- Straight fin design has 9 fins while the
Omega fin design has 12 fins a 33%
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