Study On Charge Control Of Single Fluid Zinc-Nickel Battery

Single flow zinc-nickel battery has become a new energy storage device with good development prospects due to its large energy storage scale,cost-effective,strong cycle capability and environmental protection.It is very important to improve the battery performance and energy efficiency by building a charging system to study the charging control method of single-flow zinc-nickel battery.In this thesis,the equivalent circuit model is built according to the performance parameters of single liquid zinc-nickel battery.The Buck control circuit model is established to simulate the experiment.The programmable battery charging control system is designed,and the performance test and charging experiment analysis are carried out.The DSP is used by charging control system as the core control chip.The charging control module uses PID control algorithm,AD/DC conversion by single-phase PWM rectification technology,and Buck circuit of DC/DC converter to complete the constant current charging process of batteries.The electrolyte flow rate module takes STM32F107 as the core control unit,and uses the single closed-loop PI control algorithm to control the electrolyte flow rate.The detection module uses Hall linear voltage and current sensor to collect output voltage and current signals,and flow velocity sensor to collect velocity signals.Finally,constant-current charging experiments under different voltages,currents and electrolyte velocities are carried out and analyzed by choosing appropriate variable ranges.Combined with the hardware circuit and software control algorithm,the system performance is tested.The PMW experimental waveform of MOSFET is obtained by oscilloscope,and the feasibility of the control method is verified by analysis.The final constant current charging and discharging experiments show that charging current,charging voltage and electrolyte flow rate are important factors affecting the working efficiency of single-flow zinc-nickel batteries.With the increasing of charging current(5A-10A)and charging voltage(2.02V～2.07V),the working efficiency of the batteries tends to decrease gradually.In the range of 4.6-10.2 L/min,the coulomb efficiency and energy efficiency vary nonlinearly,and the system efficiency decreases gradually with the increase of pump loss.