Study Of The Paralleled Hybrid Power System Of Lead-acid Battery And Lithium-ion Battery

In this paper, we studied the paralleled hybrid power system of lead-acid battery and lithium battery, then explored it applied for the start-stop system of micro-hybrid vehicles. The hybrid power system is simple, it utilizes the intrinsic charging and discharging characteristics of the two batteries not relys on control circuit to implement adaptive control. At present, the hybrid power generally composed by “battery+supercapacitor”, but this idea overlaps the both shortcomings of low energy density, while the higher cost of the capacitor. This paper proposes a new idea that the hybrid power system composed of paralleled lead-acid and lithium titanate batteries, which combines high energy, high specific power of lithium-ion batteries and high reliability, low cost, high security of lead-acid batteries etc, the hybrid system has a favorable technical economy and application prospect.The hybrid power system selected lead-carbon battery and lithium titanate battery by studying the charge and discharge characteristics, energy efficiency, resistance of various lead-acid batteries and lithium-ion batteries. The charging and discharging characteristics of the hybrid system were characterized and analyzed. The results indicate: the lead-acid battery have a weak charging acceptance, it will appear voltage hystereis at high charging rate. After composing hybrid power system with lithium titanate, the lithium battery will accept the main current when suffering large current pulse, avoiding the high current damage lead-acid battery. The hybrid power system helps to improve the cycle life of lead-acid batteries and improves the energy saving of start-stop system.Taking advantages of the oxygen circulation as lead-acid battery overcharging to solve the equilibrium problem of lithium-ion batteries was explored. The results showed that: at room temperature, the biggest difference of the single lithium battery decreased from 30% to 8%, it’s a significant increase in consistency.This paper studied the hybrid power system referring to the start-stop situation and the related standards of start-stop battery. The results suggest: the static and dynamic charging acceptance is relatively poor when lead-acid batteries as start-stop battery alone. After composed of hybrid power system with lithium titanate battery, the charging acceptance capability would be greatly improved. It can meet the requirements of start-stop batterry at different state.