By 2020, the energy density of lithium-ion battery cells may not be 350 watt-hours/kg?

Recently, at the press conference of “2018 China New Energy power battery and Energy Storage Industry Conference”, Xiao Chengwei, an expert of the national “863” plan for energy conservation and new energy vehicle major projects, said that according to the planning requirements of the national power battery technology roadmap By 2020, the single-energy density target for lithium-ion batteries is 350 watt-hours/kg. He believes that this target may not be achieved from the current power battery technology.

Can you realize the opinions of experts?

Xiao Chengwei believes that the ternary lithium-ion battery can now see the "ceiling" of energy density. At present, the lithium battery with high nickel material and carbon silicon anode should have a maximum energy density of 300 watt-hour/kg. It does not exceed 20 watt-hours/kg, so it is impossible to rely on a ternary material lithium-ion battery to complete the 350 watt-hour/kg technical route planning goal. To achieve the 350 watt-hour/kg technical route planning goal, we also need to hope for a new generation of lithium-ion batteries or solid-state batteries, but at present these two types of power batteries have not entered the stage of industrial application, so Xiao Chengwei is expected to achieve by 2020. The 350 watt hour/kg technical route planning goal may not be met.

For the realization of 350 watt-hours/kg, the executive vice president of the China Electric Vehicle 100-member Association, the overall expert group leader of the Ministry of Science and Technology's major electric vehicle project, the Standing Committee of the National Committee of the Chinese People's Political Consultative Conference, and the professor of Tsinghua University, Ouyang Minggao are still quite optimistic. On January 7th, he was optimistic that the density of lithium-ion power batteries is expected to reach 300 watt-hours by 2020 on the hotspot exchange meeting held by the Electric Vehicles and 100-members to grasp the trend of global change and achieve high-quality development kg.

He said that the 300 watt-hour/kg battery cell to be industrialized in 2020 has already achieved a substantial breakthrough. The technical routes adopted by Ningde era, Tianjin Lishen and Guoxuan Hi-Tech are similar: the positive electrode is high-nickel ternary and the negative electrode is silicon-carbon negative electrode. The 300 watt-hour/kg battery cell can produce a battery system of 200-210 watt-hour/kg, which is equivalent to 230 watt-hour/kg at the beginning of this year. The battery system has a capacity of 150 watt-hour/kg greatly improved.

Xiao Chengwei mentioned the "all solid lithium battery" is a lithium battery that is solid in the working temperature range and contains no liquid component. The full name is "all solid electrolyte lithium battery". This all-solid lithium battery is divided into an all-solid lithium primary battery and an all-solid lithium secondary battery. The all-solid lithium secondary battery is further divided into an all-solid lithium ion battery and a lithium metal battery.

Ouyang Minggao pointed out that there are breakthroughs, performance advantages and industrialization prospects, mainly solid-state lithium-ion batteries. The difference between it and the all-solid-state lithium battery is not all solid electrolyte, the real solid-state lithium-ion battery has an electrolyte that is solid, but has a small amount of liquid electrolyte in the cell. The so-called semi-solid is the solid electrolyte and the liquid electrolyte. Half, or half of the cell is solid, half is liquid; quasi-solid is mainly solid, a small amount is liquid.

Then the power battery can't reach the goal of technical route planning. Will the progress of China's new energy vehicle development be blocked? Xiao Chengwei thinks it should not. He pointed out that the performance of the power battery is not only an indicator of energy density, but also the power density, safety, consistency, cycle life and other factors of the power battery, in many indicators and costs. Finding a balance between industrial applications is the key to supporting the development of new energy vehicles.

Battery quality affects safety and battery life

Because China's area is relatively large, people may have more anxiety about the cruising range, so domestic power battery companies may pay more attention to specific energy density. However, some power battery companies in Europe and Japan have different focuses on power battery technology for specific power density, safety, and consistency.

Whether 350 watt-hours/kg can be achieved is not in forecasting, but also requires technological breakthroughs and industrial applications. The reporter learned that the research and development of lithium-ion battery cells at home and abroad are basically at the same level, but the safety research needs to be strengthened. The core of this battery is safety.

The experts at the meeting agreed that the quality of power batteries affects the safety and endurance of electric vehicles, especially safety issues. It should be based on prevention. It is necessary to start from the design of products, especially in the case of increasing battery energy problem. At the same time, with the expansion of power battery capacity, China's new energy vehicle power battery industry products are increasingly different, which will undoubtedly set off a new round of industrial restructuring boom.

At the meeting, Yang Weibin, dean of Huatai New Energy Research Institute, revealed that in the past two years, China’s new energy vehicles have experienced a very fast increase in battery life. On the one hand, they benefited from the increase in energy density of power batteries, and on the other hand, they benefited from the rapid decline in cost. . With the advancement of power battery technology and the cost reduction, coupled with policy concessions, the advantages of electric vehicles over traditional fuel vehicles will gradually emerge in the future. Yang Weibin predicts that with the expansion of the industry scale and the large-scale application of power battery recycling, there will be room for further decline in power batteries in the future. Xiao Chengwei pointed out that power battery technology is developing rapidly, but everyone has high requirements for batteries, and hopes to achieve the degree of competition with fuel vehicles, energy density, power density, safety, cycle life, fast charging, temperature range and cost. Both can achieve the desired goals, so the power battery industry still faces greater challenges, but he believes that these goals can be achieved, or nearly reached, through the efforts of the entire industry.

Liu Yong, secretary-general of the Energy Storage Application Branch of the China Chemical and Physical Power Industry Association, stressed that the energy storage industry needs the attention of both the user side and the new energy power generation side. The future focus should be on life cost and safety, applications in emergency power and communications.

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