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Battery quality affects safety and battery life

Time:2021-01-18 Views:128

  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.

Battery quality affects safety and battery life

  Can the 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 at present 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 watt-hour/kg technical route planning target may not be achieved.

  Regarding whether 350 watt-hours/kg can be achieved, Ouyang Minggao, executive vice chairman of the my country Electric Vehicles Association of 100, head of the overall expert group of major electric vehicle projects of the Ministry of Science and Technology, CPPCC Standing Committee, 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 Wh/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 high nickel ternary, and the negative electrode is silicon carbon. A battery cell of 300 Wh/kg can produce a battery system of 200~210 Wh/kg. This compares with a cell energy density of 230 Wh/kg at the beginning of this year and a battery system of 150 Wh/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 most important thing with breakthroughs, performance advantages and industrialization prospects is 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 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.

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