What compressibility of thermal pad is good for battery pack application?

What compressibility of thermal pad is the best for application? No body can answer affirmatively, because it varies with different design and specific application. For example, what compressibility of thermal pad is good for battery pack? Here is a case.

One of our customers designed a thermal pad for battery pack, requesting a compressibility of 50%, no problem, it is easy to proceed. But the next specification makes you feel dilemma, the maximum pressure is 100kPa. According to current raw material status, that is practically impossible, even the top class brand such as Bergquist, 3M or Fujipoly can not offer such a thermal pad.

Actually, battery modules can withstand much higher pressure than 100kPa, the frame of battery modules is made from plastic. By the test, 700kPa of pressure will not exihit adverse effect to modules. Can we expect a better performance from the biggest compression? Not really.

We had experienced a lot of case, 30% of compression is good to optimize heat transfer. Thermal pad can contact heat source and heat sink tightly, filling small gaps and expelling air. At the meantime, thermal pad works as vibration dampening cushion to protect components.

We don't need a maximum compression, if we apply much more forces, it may break components. Thermal pad perfectly contact with  heat source and heat sink will optimize thermal transfer, making devices work at their best.