Meaning
High-temperature polymer films provide electrical insulation and chemical protection for sensitive electronic and electrochemical surfaces. Applying a polyimide coating to current collectors or circuit boards within a battery pack prevents electrical short circuits and protects against corrosion from electrolyte leakage.
Material Performance
Polyimide resins withstand extreme temperatures without melting or losing their mechanical strength. When used as a polyimide coating, the material maintains its structural integrity up to four hundred degrees Celsius, which is well above the thermal runaway temperature of most lithium cells. This thermal stability prevents the insulating layer from failing during localized overheating events.
In addition, its low moisture absorption ensures that its dielectric properties remain stable in humid environments.
Electrical Isolation
Thin layers of this polymer offer high dielectric strength, allowing for thin insulating barriers that do not add significant volume to the pack. This insulation prevents short circuits between adjacent cells and the module frame. The coating is applied to the copper busbars or flexible circuits that connect the voltage monitoring pins.
Sourcing Selection
Designers select these coatings for their chemical inertness and resistance to aggressive organic solvents. This choice ensures the insulation does not degrade in the presence of electrolyte vapor.
