Battery quality affects safety and battery life, and the per

 news     |      2021-12-03 15:47

Recently, at a domestic conference, Xiao Chengwei, an expert from the national "863" plan energy conservation and new energy vehicle major project overall expert group, said that according to the planning requirements of the national power lithium battery technology roadmap, by 2020, the single energy density of lithium ion batteries The target is 350 watt-hours/kg. He believes that from the current power lithium battery technology, this target may not be achieved.

Whether it can be realized that experts have different opinions

Xiao Chengwei believes that ternary lithium-ion power lithium batteries can already see the "ceiling" of energy density. The current lithium-ion batteries with high nickel materials and carbon silicon anodes should have a maximum single energy density of about 300 Wh/kg. The plus or minus does not exceed 20 Wh/kg, so it should be impossible to rely on the ternary material lithium-ion battery to complete the 350 Wh/kg technical route planning goal. To achieve the technical route planning goal of 350 watt-hours/kg, hope is also placed on a new generation of lithium-ion batteries or solid-state batteries, but currently neither of these two types of power lithium batteries has entered the stage of industrial application. Therefore, Xiao Chengwei predicts that by 2020 Achieving the 350 Wh/kg technical route planning target may not be achieved.

Regarding whether 350 watt-hours/kg can be achieved, Ouyang Minggao, the executive vice chairman of the my country Electric Vehicles Association of 100, the leader of the overall expert group of major electric vehicle projects of the Ministry of Science and Technology, the Standing Committee of the National Committee of the Chinese People's Political Consultative Conference, and Tsinghua University professor Ouyang Minggao is still relatively optimistic. He said that the density of lithium-ion power lithium batteries is expected to reach 300 watt-hours/kg by 2020.

He said that a substantial breakthrough has been made for the 300 watt-hour/kg battery cell to be industrialized in 2020. For example, Ningde Times, Tianjin Lishen and Guoxuan High-Tech have adopted similar technical routes: the positive electrode is a high nickel ternary, and the negative electrode is a silicon-carbon negative electrode. A battery cell of 300 watt-hours/kg can produce a battery system of 200~210 watt-hours/kg. This is compared with the cell energy density of 230 watt-hours/kg at the beginning of this year and a battery system of about 150 watt-hours/kg. Great improvement.

The "all-solid-state lithium-ion battery" mentioned by Xiao Chengwei is a lithium-ion battery in which the electrodes and electrolyte materials used in the working temperature range are solid and do not contain any liquid components. The full name is "all-solid-state electrolyte lithium-ion battery" ". This all-solid-state lithium-ion battery is divided into all-solid-state lithium primary batteries and all-solid-state lithium secondary batteries. All solid state lithium secondary batteries are further divided into all solid state lithium ion batteries and lithium metal batteries.

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

Then the power lithium battery cannot reach the goal of the technical route planning, will the development process of my country's new energy vehicles be hindered? Xiao Chengwei believes that it should not. He pointed out that it is not only the specific energy density that affects the performance of power lithium batteries, but also the specific power density, safety, consistency, cycle life and other factors of power lithium batteries. Finding a balance between industrial application and cost is the key to supporting the development of new energy vehicles.

Battery quality affects safety and battery life

Because of the larger area of our country, people may be more anxious about the cruising range, so domestic power lithium battery companies may be more concerned about specific energy density. However, some power lithium battery companies in Europe, Japan, etc., have their own focus on specific power density, safety, consistency and other indicators in power lithium battery technology.

Whether 350 watt-hours/kg can be achieved is not about prediction, but more about technological breakthroughs and industrial applications. The reporter learned that the current domestic and foreign lithium-ion power lithium battery cell technology research and development are basically at the same level, but safety research needs to be strengthened. The core of this battery is safety.

Experts agree that the quality of power lithium batteries affects the safety and endurance of electric vehicles. In particular, safety issues should be based on prevention. We should start with product design, especially when the battery's specific energy continues to increase, the more attention should be paid to safety. problem. At the same time, with the expansion of power lithium battery production, my country's new energy vehicle power lithium battery industry is becoming more and more diverse, which will undoubtedly set off a new round of industrial restructuring.

Yang Weibin, Dean of Huatai New Energy Research Institute, revealed that my country's new energy vehicles have increased very rapidly in the past two years, thanks to the increase in the energy density of power lithium batteries on the one hand, and the rapid decline in costs on the other hand. . With the advancement of power lithium battery technology and the decline in cost, coupled with policy preferences, the advantages of electric vehicles relative to traditional fuel vehicles will gradually appear in the future. Yang Weibin predicts that with the expansion of the industrial scale and the large-scale application of power lithium battery recycling, there is still room for further decline in power lithium batteries in the future. Xiao Chengwei pointed out that power lithium battery technology has developed rapidly, but everyone has high requirements for batteries, hoping to reach the level of competition with fuel vehicles, energy density, power density, safety, cycle life, fast charging, temperature range and use The cost can reach the expected goals, so the power lithium battery industry is still facing greater challenges, but he believes that with the efforts of the entire industry, these goals can be achieved, or close to being achieved.