Research On Key Materials And Circuit Simulation Design Of Radioisotope Battery Energy Storage System

Marine monitoring equipment has attracted wide attention in the development and utilization of marine resources in recent years.However,the commonly used power supply for marine monitoring equipment currently cannot work for long periods of time in deep sea and other harsh environmental conditions.The widespread application of monitoring equipment is limited.Radioisotope battery can directly convert the energy generated by nuclear radiation into electrical energy and can operate stably for decades in harsh environments.Therefore,it has broad application scenarios in marine monitoring equipment.But radioisotope battery can’t independently power high-power equipment due to the low output characteristics.It needs to introduce a power source for power compensation to supplement the power of radioisotope battery.Because of the advantages of low self-discharge and no pollution to the marine environment.The aqueous lithium-ion battery can be used as a power compensation power supply in marine monitoring equipment.This article designed the energy storage subsystem of radioisotope batteries based on their output characteristics and application scenarios.This subsystem consists of a power compensation battery and a power regulation circuit.Radioisotope battery and aqueous lithium-ion battery can be coupled through power regulation circuits to achieve power management of the power supply.The work of this article is mainly divided into two parts:（1）Modification research has been conducted on commonly used positive electrode materials for power compensation battery to improve the cyclic stability of energy storage subsystem.The influence of different preparation processes on the electrochemical properties of LiMn₂O₄ was investigated.LiMn₂O₄ obtained by high-temperature solid-state method showed better electrochemical performance.This battery can maintain 67%of the initial discharge capacity(119 mAh·g^-1)after 100 cycles.Then,a layer of silicon dioxide was coated on the surface of LiMn₂O₄.The coating layer was used to isolate the positive electrode material from the electrolyte.The coating layer can effectively improve the cycling life of the battery.The cycling stability of the battery is the best when the coating amount is 1 wt.%.Its capacity retention rate was 90%after 50 cycles.Finally,the effect of different conductive agents on battery performance was studied.It was found that the battery has the best electrochemical performance when VGCF were used as conductive materials.The LiMn₂O₄ can maintain 88.5%of the initial discharge capacity(119.4 mAh·g^-1)after 100 cycles.（2）Designed a power regulation circuit to successfully couple radioisotope battery with lithium-ion battery.The schematic diagram of the power regulation circuit was designed through the functional requirements of the equipment,and analyzed its working principle,working mode,power flow direction under different working states.The feasibility of the circuit was simulated and verified.Then,corresponding working modules were designed according to the functional requirements of the circuit.The physical construction of the circuit was carried out and the circuit board was tested and verified.The results show that the power regulation circuit designed based on a three-port converter can successfully couple radioisotope battery and lithium-ion battery.It also can automatically switch the circuit working mode under the control of a microcontroller.The power management of the battery can be achieved according to the different operating states of the circuit.This article focuses on the design of an energy storage subsystem for radioisotope battery.The power regulation circuit was designed based on a three-port converter to couple radioisotope battery with lithium-ion battery.The long-term operation of equipment has been achieved through power management.This subsystem can provide important technical references for the application of isotope batteries in the ocean and expanding the application scenarios of radioisotope batteries.It also has very important guiding significance for the miniaturization and lightweight design of marine monitoring equipment.