In CPM, the supercapacitors serve as the core energy storage component, and its selection directly determines the reliability, timeliness, and safety of the unlocking action. Compared with lithium batteries, supercapacitors are based on a double-layer physical energy storage mechanism, which allows millisecond-level charging and discharging without chemical reactions. Their stability and instantaneous power output capability under extreme conditions better meet the core requirements of collision unlocking, making them the preferred energy storage solution for this scenario.

When selecting supercapacitors, the key factor should be the energy requirement for unlocking. The first considerations are capacitance, voltage, and the number of supercapacitors. Considering the size of supercapacitors, commonly selectable capacitances are 25F and 30F; rated voltages are 2.5V, 2.7V or 3V. Supercapacitors can be connected in series to increase energy, with common series numbers being 1 to 5. The energy calculation formula is:

Taking example of three 2.7V, 25F supercapacitors connected in series to calculate the energy that can be released.

Equivalent capacitance：

25F/3 = 8.33F

Operation voltage range ：

8.1V ~ 3V

Released energy：

When a supercapacitor discharges, considering the impact of internal resistance, the voltage can drop to as low as 3V. Therefore, the operating range is from 8.1V to 3V. At different voltages, capacity and series combinations can meet different energy requirements. Therefore, when selecting a supercapacitor, it is necessary to choose according to the energy required by the system, while leaving a certain margin, generally considered to be around 30%.

The equivalent series resistance (ESR) of supercapacitors is also a key factor affecting the unlocking response speed. Collision unlocking requires driving the door lock motor to generate an instantaneous large current, and low ESR can reduce energy loss and heating. For automotive-grade selection, priority should be given to products with an ESR of less than 30mΩ at room temperature, ensuring that the instantaneous discharge current reaches above 15A, and even in a -40°C low-temperature environment, it can still maintain an output capacity of over 10A to meet the normal driving requirements of the door lock motor.

Supercapacitors must meet automotive-grade reliability and safety standards when selecting models. CPM needs to work throughout the entire vehicle lifecycle; therefore, the cycle life of the supercapacitor should reach more than 500,000 times. Temperature adaptability is also essential, and the supercapacitor needs to cover a wide operating temperature range of -40°C to 105°C.