A super capacitors is a very large capacitor with a capacitance of up to thousands of farads. According to the principle of the capacitor, the capacitance depends on the distance between the electrodes and the surface area of ​​the electrodes. In order to obtain such a large capacitance, it is necessary to reduce the distance between the electrodes of the supercapacitor as much as possible and increase the surface area of ​​the electrodes. For this reason, the principle of electric double layer and the porous activated carbon electrode.

The battery is a key electrical component in a car, and its performance directly affects the start of the car. The current car start without exception uses the starter motor start method. During the starting process, especially at the moment of starting, since the starting motor speed is zero and no induced potential is generated, the starting current: I=E/(RM+RS+RL); where: E is the no-load terminal voltage of the battery, RM It is the armature resistance of the starting motor, RS is the internal resistance of the battery, and RL is the line resistance. Since RM, RB, and RL are all very low, the starting current is very large. For example, using a 12 V, 45 Ah battery to start a car with a 1.9 L diesel engine, the voltage of the battery drops from 12.6 V to about 3.6 V at the moment of starting. The battery voltage waveform during the starting process is shown in Figure 1. The instantaneous current at startup is 550 A, which is approximately 12C discharge rate of the battery> battery current waveform during startup. The current/voltage conversion ratio of the current sensor is 100 A/V. Although the car battery is a special battery for starting, it can discharge at a high rate, but the performance of the battery becomes very poor when the high rate discharge is more than 10 times, and the damage to the battery is very obvious when the high rate discharge is so high. The drastic voltage change during the start-up process is also a very strong electromagnetic interference, which can cause the electrical equipment to lose power, forcing the electrical equipment to re-energize after the generator starts, and the computer is very easy to crash during this process. Therefore, from the perspective of improving the electromagnetic environment of automobile electrical equipment, improving the starting performance and battery performance of the automobile, or extending the service life of the battery, it is necessary to improve the performance of the automobile power supply during the starting process. One of the solutions to the problem is to increase the capacity of the battery, but it needs to be increased a lot and its volume is increased, which is not a good choice. Parallel connection of super capacitors with batteries can solve this problem well.