Lithium battery bottleneck cannot be broken

In recent days, there have been many discussions on the data of new energy vehicles in the first half of the year. According to the news released by the Ministry of Industry and Information Technology, the output of new energy vehicles in China increased sharply in the first half of the year. From January to June 2015, the cumulative production of new energy vehicles totaled 78,500 units, a three-fold increase over the same period last year. Among them, the production of pure electric passenger vehicles was 36,300 units, a three-fold increase over the same period of last year. The plug-in hybrid passenger vehicles produced 20,400 units, a year-on-year increase of 4 times; the production of pure electric commercial vehicles was 15,500 units, a year-on-year increase of 5 times. Electric hybrid commercial vehicles produced 6,406 units, a year-on-year increase of 74%.

Looking at such bright data, many people will feel more confident. But in fact, the development of new energy vehicles is still a hidden danger, and battery is one of the most important factors limiting development.

Recently, at the 4th China Electric Power Development and Technology Innovation Academician Forum hosted by the Chinese Academy of Electric Power, Yusheng Yang, an academician of the Chinese Academy of Engineering, proposed that the development of electric vehicles depends on the development of batteries and electric vehicles. Otherwise, you may face greater danger.

“The development of pure electric buses under high subsidies is abnormal, and the armpits are found in various cities, and the country’s losses are serious.” He pointed out that with the current energy- enhanced lithium-ion batteries. The reasonable design mileage of pure electric vehicles is about 150 kilometers. If the mileage is long, more batteries are needed, the body is heavy, energy is wasted, and safety is poor. Such as BYD e6, the battery weighs 700 kilograms, the power consumption is 19.5 degrees per 100 kilometers; Tesla also burned 7 cars in 2 years because of the poor safety of the battery.

Compared with pure electric vehicles, Yusheng Yang is more admired for the extended-range electric vehicle, because the generator charges the battery while the vehicle is running, and the battery always runs between the semi-filled and the semi-discharged state. The advantage of this state is that the internal resistance of the battery is minimized and the heat generation is small; however, charging is safe and secure; however, the cycle life is long; the inconsistency problem is diluted; the power management system can be simplified.

“Beijing advocates the development of pure electric vehicles, and believes that the addition of electric vehicles to oil-burning is not environmentally friendly. But I think that if you change all the cars in Beijing into an extended-range vehicle, you can save half of the fuel consumption, which is easier to do. But it is very difficult to replace half of all cars in Beijing with pure electric vehicles," he said.

Another type of vehicle that he believes should be developed vigorously is a small short-range electric vehicle. He disapproves of the fact that many people now compare the driving range of electric vehicles with traditional cars. "The specific energy of the battery is about 50 times smaller than that of gasoline. It is difficult for electric vehicles to reach the level of traditional cars. 'Well, vigorously develop small short-range electric vehicles to achieve the goal of green energy conservation. But now this car has not yet obtained a 'birth certificate', or illegal products." He regretted.

For the development of China's battery industry, Yusheng Yang gave four suggestions:

The first is to be safe first, not to pursue high specific energy. Batteries are energetic devices that have varying degrees of danger and do not have an absolutely safe battery. But the difference in security is great. It is better to use high-safety batteries, preferring to sacrifice some specific energy. Lithium-ion batteries need to increase specific energy, but pay special attention to safety first. At the same time, in the design of large-scale electricity storage, it is necessary to control the chain reaction; in the use of safety procedures must be adhered to, must not be abused, abuse will have a great impact on battery life.

Second, we must pay attention to environmental issues, because the batteries are made of chemical materials, improper handling will pollute the environment. However, Yusheng Yang disagreed with the saying that many people think that lead-acid batteries pollute the environment and lithium-ion batteries are green.

“The lead-acid battery itself does not pollute the environment. The production and recycling of lead processing, such as poor management and poor supervision, may cause harm to the environment, but it is not a battery problem. The output of lead-acid batteries in the United States is equivalent to that of China, and it is not a polluting industry. It is wrong to say that the lead-acid battery pollutes the environment. It is unreasonable to introduce the lead-acid battery consumption tax in 2016. He said that it is not true that the lithium-ion battery is green in general, because the lithium-ion battery contains many chemicals and the production process is also problematic. If it contains lithium hexafluorophosphate, the fluorine-containing chemical is used in the preparation, and in the treatment of the waste battery, hydrogen fluoride is generated upon encountering water vapor. Moreover, the waste lead-acid batteries are basically recycled, and the problem of discarded lithium-ion batteries is more prominent.

Once again, it is necessary to be compatible with the development of the battery industry, there is no omnipotent battery. The ruler is short and the length is long. Don't say that a certain battery will replace a certain battery, but use a variety of batteries to fully utilize its new technology and new uses. At the same time, we must seriously consider hard work and innovation not follow the trend; we must welcome the birth of new battery systems and new materials technology, but be wary of stealing concepts, confusing, exaggerating and other behaviors.

"For example, nickel-carbon super capacitor is actually nickel-metal hydride batteries with activated carbon, in addition to long life, other performance is not prominent. There is also a world of the era of aluminum battery is also a bit exaggerated." Yusheng Yang said.

Finally, all technologies have the next generation, but the next generation must be seriously demonstrated. For example, the next generation of lithium-ion batteries is a lithium-sulfur battery, and the next generation is a lithium-air battery; the next generation of lead-acid batteries is developed into a super battery, and then developed into a lead-carbon battery.

So how should the next battery develop? Yusheng Yang also gave the answer.

Lithium-ion batteries should put safety first, study high specific energy, high specific power, long life, wide temperature range, high voltage, expand various application technologies, continue to demonstrate large-scale energy storage; lithium-sulfur batteries It is necessary to overcome the three majors of life, power and safety, and can focus on innovative sulfur-lithium ion batteries; liquid flow batteries should increase automation and energy efficiency, do not expand the scale, reduce costs, summarize economic benefits; super capacitors to break through the high-performance super-activated carbon material technology, replace imports, reduce costs and so on.

He also warned that the development of four types of batteries should be considered seriously, even considering whether to continue. Including lithium flow batteries with questionable safety, high cost and inconvenient operation; Sodium sulfur batteries with poor safety; Lithium air (oxygen) battery; Low energy efficiency and complex system of renewable fuel cells.

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