SHANGHAI, Oct 22 (SMM) – At the 2021 (11th) China Secondary Lead Battery Industry Summit and China Lead-acid Battery Scrap Recycling Industry Summit held by SMM, Lin Haibo, a professor at the School of Chemistry of Jilin University, gave an explanation on the research on externally applied lead-carbon batteries, and gave his forecast on its development prospects.
Lead-carbon battery research
In recent years, more and more attention has been paid to the research and development of lead-carbon batteries, and the manpower and material investment in the basic research and development of lead-carbon batteries in various countries has gradually increased. However, there are various material and mechanism problems in the lead-carbon battery industry.
Special lead-carbon battery: externally-applied lead-carbon battery
Compared with the traditional lead-carbon battery, the externally-applied lead-carbon battery optimizes the secondary potential distribution in the conductive network, and has a larger electrolyte contact area, which allows it to have a higher specific capacitance and a stable charge buffer, which enhances the instantaneous high-current withstand capability of the battery, has prolongs the cycle life at high rates, and stabilise the discharge in a low-temperature environment.
However, the sulphation of the surface of the carbon material interferes will affect the double electric layer as well as the catalytic properties, which may accelerate the degradation of the electrode cycle life. Thus the research on carbon materials is very important.
The mechanism of carbon materials in externally-applied lead-carbon batteries
The main purpose of adding carbon materials is to inhibit sulphation and increase energy density.
The application of externally-applied lead-carbon battery
From 2014 to 2020, the market shares of the micro-hybrid vehicles equipped with 12V lead-acid batteries and the light-hybrid vehicles equipped with 48V lead-acid batteries have increased year by year. It is estimated that by 2025, the market share of micro-hybrid vehicles equipped with 12V lead-acid batteries in Europe, China and North America will reach 50~60%.
In addition, the most suitable battery for short-range electric vehicles is the lead-acid battery for its lowest risk, and the external lead-carbon battery is one of the best alternatives to the lead-acid battery. Therefore, short-range electric vehicle market is one of the application areas of lead-carbon batteries. And stationary energy storage is also one of its applications. Future trends, difficulties and breakthroughs. The cars with start-stop system are undergoing a transition from P0 to P4 structure, and their battery requirements are gradually increasing. The 48V battery under the P4 structure has attracted much attention. Compared with the 12V system, the 48V battery system has a higher fuel-saving rate of up to 10%; and it will not cause serious electric shock when powered by the 48V battery. In the future, the current in automotive electrical appliances needs to reach more than 100A, and the total power needs to reach more than 3KW. The 48V battery power supply current can reach 130A, and the power supply can reach 10KW, which can meet the electricity demand.
Future trends, difficulties and breakthroughs
The start-stop system cars are undergoing a transition from P0 to P4 structure, and their battery requirements are gradually increasing. The 48V battery under the P4 structure has attracted much attention. Compared with the 12V system, the 48V battery system has a higher fuel-saving rate of up to 10%, and it will not cause serious electric shock when powered by the 48V battery.
In the future, the current in automotive electrical appliances needs to reach more than 100A, and the total power needs to reach more than 3KW. The 48V battery current can reach 130A, and the power supply can reach 10KW, which can meet the demand.
The application and challenge of externally-applied lead-carbon battery in 48V battery
The energy and power density of nickel-hydrogen battery can meet the demand, but its high charging temperature and high costs have limited its large-scale promotion.
With the decline in the cost of lithium batteries, the temperature restrictions and safety have become the most critical issues. Considering the expensive auxiliary equipment, the prices of the 48V lithium battery start-stop system may remain high.
The performance of the lead-carbon battery can meet all the requirements. When the batteries are assembled into a battery pack, the unit cells have self-regulation characteristics, so the requirements for the parallelism of the unit cells are relatively low. It is easier to assemble and design than the 48V lithium batteries, and the costs of support equipment are low. It still has much room for improvement in the performance in high and low temperatures.
Therefore, the 48V lead-carbon start-stop battery has high feasibility and market competitiveness.
The high and low temperature endurance of externally-applied lead-carbon batteries
In the vehicle design, the battery is often close to the motor, and the temperature of the motor is higher than 70°C when it is working. In winter, the static environment inside the car is lower than -20℃, and a higher discharge current is required to better realise the cold start of the car. The LTO battery may be dangerous working in the high temperatures, and its discharge current is small in the low temperatures. The low-temperature lithium iron phosphate batteries are too expensive.
The externally-applied lead-carbon batteries can endure the temperature between 35-70℃, which is much better than that of lithium batteries, nickel-hydrogen batteries, etc. But it still has the room for improvement.