Lithium battery is mainly composed of two blocks, the cell and the protection board PCM (power battery is generally called battery management system BMS), the protection board is mainly composed of protection chip (or management chip), MOS tube, resistance, capacitance and PCB board The battery is equivalent to the heart of lithium battery, the management system is equivalent to the brain of lithium battery, the battery is mainly composed of positive material, negative material, electrolyte, diaphragm and shell.