Lithium batteries, fuel cells, and supercapacitors who are the ultimate home of electric car batteries?

Since the world faces energy crisis and environmental pollution, new energy vehicles have taken on the responsibility of solving the above problems. However, from the perspective of the promotion of countries around the world, it is not ideal. In addition to the infrastructure construction that cannot meet the needs of the market, new energy vehicle battery technology is the main factor constraining development.

For consumers, the mileage of new energy vehicles is an important consideration. From the current point of view, the longest cruising range in practical applications is the Tesla Model S electric vehicle, with a maximum cruising range of 502 kilometers and conversion energy consumption of 169 watt-hours/km. Although Beijing Hongyuan Lanxiang Electric Vehicle Technology Co., Ltd. tested the modified Xiali N7, a charge continued to travel 682 kilometers, the domestic car conversion energy consumption was 101 watt-hour/km, much lower than Tesla, but only test data, No commercial mass production yet. The mileage of other new energy vehicles is far lower than that of Tesla.

The battery is also an important factor that restricts the mileage of new energy. At present, there are three directions for the development of new energy batteries: lithium batteries, fuel cells, or super capacitors. From the current application situation, the most widely used is the lithium battery, followed by the fuel cell, ultracapacitor battery is still in the ideal stage.

lithium battery

For lithium batteries, according to the different materials are divided into lithium iron phosphate batteries, lithium cobalt oxide batteries and lithium polymer batteries.

Most electric vehicles use lithium iron phosphate batteries such as Chevrolet Volt, Nissan Leaf, BYD E6, and others. This kind of battery technology is mature and safe, but its disadvantage is its energy density, which results in the short range of the electric vehicle and it is difficult to meet the requirements of consumers. In addition, the synthesis reaction of the lithium iron phosphate battery is complicated, resulting in battery consistency problem is difficult to solve, in addition, lithium iron phosphate battery manufacturing process requires reducing gas, resulting in the stability and accuracy of the material is difficult to control; zero temperature The following lithium iron phosphate batteries have no effect on power supply and affect the use of vehicles.

Lithium cobaltate battery and ternary polymer lithium battery are mainly Tesla electric vehicles, the Roadster electric vehicle uses lithium cobalt oxide battery, Model S uses a ternary polymer lithium battery. For lithium cobalt oxide batteries, although the energy density is large, the safety is low and the cost is high. Take Tesla as an example, its battery cost accounts for half of the whole vehicle. Therefore, Tesla uses a ternary polymer lithium battery with high energy density but lower cost.

In addition to the fuel cell, the fuel cell is the major automotive manufacturers focus on investment. The outstanding features of hydrogen fuels as energy sources are pollution-free, efficient, and recyclable. Hydrogen is a colorless gas. Burning one gram of hydrogen can release 142 kilojoules of heat, which is three times the heat of gasoline. Its combustion product is water, no ash and waste gas, no pollution to the environment, so hydrogen as fuel is considered to be the most ideal energy source for the 21st century.
In recent years, with strong support from the government in Europe, America and Japan, certain achievements have been made in the research and development of hydrogen fuel vehicles. Giant companies such as Mercedes-Benz, General Motors, and Toyota have all laid out one after another. The Japanese government is actively promoting the development of hydrogen fuel cell vehicles in the country. According to the "New Growth Strategy" plan, the Japanese government proposes the following goals: The market share of next-generation eco-cars, including hydrogen fuel cell vehicles, will increase from about 23% in 2013 to 50% to 70% in 2030. At the same time, it provided subsidies for hydrogen fuel cell vehicles, bringing its price to be the same as that of hybrid vehicles in 2025, and the integration of standards with international standards to promote its overseas sales was listed as a key implementation project.

In July 2014, at a briefing meeting on the development of hydrogen fuel cell vehicles (FCVs) in Tokyo, Toyota’s Vice President Kato Koichi stated that it will introduce sedan-type hydrogen fuel vehicles to the market in 2014. In June, modern hydrogen fuel cell vehicles were first sold in Southern California in the United States, meaning that the mass production of hydrogen fuel cell vehicles began to enter the commercial release phase in the United States. Honda will also launch a fuel cell vehicle in 2015.

However, hydrogen fuel cells also have certain disadvantages. Fuel cell production costs are high, and the construction of hydrogen refueling stations is even more difficult than charging stations for lithium battery electric vehicles. In addition, there are hidden dangers of hydrogen explosion and limited sources of hydrogen. The above reasons have restricted the application of hydrogen fuel in the market.

Super capacitor

For supercapacitors with broader market prospects, they are theoretically superior to lithium batteries and fuel cells. It has been predicted that the batteries of conventional electric vehicles are outdated, and that new types of vehicles using super-capacitor-powered systems will be replaced in the future. Its advantages are first of all superfast charging speed, regardless of the capacity, as long as the current is enough, one or two seconds will be able to fill; followed by resistance, hundreds of thousands of times no problem, and the energy does not decay; the third is very fast discharge, or It is said that the power that can be carried is high, which is also not comparable to the battery; Fourth, the efficiency is high. Because of the physical changes, its energy conversion efficiency is far from the chemically comparable battery.

However, supercapacitors also have their own drawbacks: one is safety, too fast discharge speed and too low internal resistance, if the design is not good, it inherently contains the risk of "sudden burst of energy." The second is lower operating voltage, which restricts its application in driving the car.

Forward-looking network of new energy automotive industry report analysis, from the above three kinds of batteries compared to the perspective of lithium batteries in the short term is still the main, and will show the phenomenon of lithium batteries and fuel cells go hand in hand. For supercapacitors, it is difficult to replace lithium batteries in the short term. From a technical point of view, supercapacitors and lithium batteries each have their own performance characteristics. The combination of lithium batteries and supercapacitors will become the mainstream in the market.