The link between subsidies and mileage will affect the safety of power cells

"How should the power battery develop? In fact, it is closely related to how electric cars develop. What kind of battery develops what kind of electric car, not beyond the battery level to dream up the electric car target. "According to Yangyusheng, an academician of the Chinese Academy of Engineering.

On April 20-21, the "2018 First China New Energy power battery and energy storage Industry Conference" with the theme of "New Energy Conversion and High-Quality Development" was held in Taizhou, Jiangsu Province. At the meeting, Academician Yangyusheng published "Thinking on the problem of high-power power batteries." He said that the purpose of developing electric vehicles is to save energy and reduce emissions. The automotive power must rely on independent intellectual property rights to produce electric vehicles with the lowest energy consumption and the lowest emission.

The new subsidy policy should take safety into account

What are the following aspects of power battery performance requirements? How are the requirements ranked?

Yangyusheng said that the most important power battery is high safety, not flammable, explosion. The second most important is the long cycle life, low price, high specific power, high conversion efficiency, high specific energy, easy to use and easy to maintain. The third is cold and hot, rich in resources and a friendly environment.

"Subsidies and the upcoming policy of linking points to pure electric mileage have misled the excessive increase in battery specific energy and the use of batteries. Academician Yangyusheng believes that the new subsidy policy ignores that the higher the battery than the energy, the more the battery, the lower the safety.

Now that we focus on the development of pure electric vehicles, we still need to relieve the four major anxieties:

The first is mileage anxiety. Bring more batteries, still afraid of power outages. The car is heavy and does not save electricity.

Second safety anxiety: more batteries than energy will be high, dangerous, more combustion explosion accidents.

The third is charging anxiety. Although the charging pile is becoming more and denser and the investment is very large, it is still difficult to meet the demand for charging.

Fourth, price anxiety, large battery use, product prices are high, competitiveness is low.

Yangyusheng stressed that the development of highly subsidized pure electric vehicles is difficult to market. When there is a subsidy, special vehicles such as medium-sized logistics vehicles can be developed, but the second battery requires the user to pay. We now have more than 1.7 million electric cars in the country, and the longer the subsidy stops, the more difficult it will be to sell the cars that have been subsidized.

So what to do, Mr. Yangyusheng says, is, in principle, to use mature batteries to develop safe, energy-efficient, emission-reducing electric vehicles. In the technical route, it is necessary to use small and medium-sized pure electric vehicles as a breakthrough, and large and medium-sized vehicles develop purely electric-driven augmented vehicles. For miniature pure electric vehicles, lead-acid batteries can be used as low-speed vehicles, or lithium batteries can be used as high-speed vehicles, and finally handed over to the market to decide.

Academician Yangyusheng, who has always advocated the development of additional electric vehicles, believes that there are no four major anxiety problems for pure electric vehicles. At present, augmented electric vehicles have developed into third-generation products. "The first generation simply increased the mileage, so the engine power is large, the battery weight is large, and the vehicle's self-weight is also large, resulting in high fuel consumption. The second generation optimized the power system and saved 50 cents on the original basis. The third generation is the increase in power generation direct-drive electric vehicles. The electricity generated by the generator in the car directly drives the motor without a battery, inheriting all the advantages of the second generation, and further reducing the cost, with a fuel-saving rate of up to 60.

What other high-power batteries will there be in the future?

Fuel cells are seen as one of the most promising power cells in the future.

Yangyusheng pointed out that fuel cells are higher than energy, but it is difficult to meet the requirements of power changes in the driving of cars. The power demand must be adjusted by batteries. Yangyusheng says the first of the five major problems facing fuel cells is the variety of fuel cells. "Is a proton exchange membrane fuel the best battery? However, there are still the following five major issues. The first is the energy efficiency and low emission preparation of hydrogen; The second is the safe transportation and storage of hydrogen, and the hydrogenation station is also more expensive; The third is a short life and high price of fuel cells. Fourth, membrane and other key materials technology need to be improved. The fifth platinum resources are too few and platinum-free catalysts need to be developed. "

"In short, the technical route of fuel cell electric vehicles are still being explored. Heavy subsidies and drastic promotion of PMFC industrialization will cause waste and fraud," said Yangyusheng.

Lithium-sulfur batteries are also more and more concerned about the power cell type in the industry. In Yangyusheng's view, lithium-sulfur batteries are "easy to enter," but it is difficult to do well. "Lithium-sulfur batteries have five low: low safety, low volume than energy, low discharge ratio, low energy conversion efficiency, and low cycle times. Only after solving the five low problems can it be used as a vehicle power battery. Three years and five years is difficult to use in the car, and ten years and eight years is not pessimistic. "

In addition, lithium empty batteries are considered to be the "next generation" power cells after lithium-sulfur batteries. It is understood that the lithium empty battery has an energy of up to 700Wh / kg, and the mileage can be comparable to that of a fuel truck. Yangyusheng said, "But the lithium empty battery is likely to be far hydrolyzed not far thirsty. It is not yet a more secure battery type for many years. The energy conversion efficiency is too low, the life is short, and the function is lower than the function. "

Yangyusheng pointed out that electric cars can be sold, whether it is high or low speed, and it is necessary to reduce the use of batteries and reduce the price of the car, rather than pursuing long-term mileage, desperately improving energy, or installing more batteries to increase the risk.

So how will the future power battery develop? Yangyusheng gave the following advice: First, power batteries should be miniaturized, followed by the development of augmented electric vehicles, gradually to market. Third, the power generation direct drive program electric vehicles to increase the oil generation capacity of the extender, without demanding the high specific energy of the battery.

The page contains the contents of the machine translation.