Lithium ion battery is an ideal way to store energy

At the international energy storage summit and exhibition 2018 (ESIE) held in Beijing not long ago, wang zidong, director of the China north vehicle research institute and the national 863 power battery testing center, gave a keynote speech on how to make the energy storage industry environmentally friendly.

Wang zidong pointed out that China is a big energy importer, with more than 60% of primary energy imports, and strategic energy security has great risks. At present, China's power generation structure is not reasonable, the proportion of thermal power is too large, "to improve the power generation structure, and actively develop new energy and clean green energy power generation, is undoubtedly a top priority. Electrochemical energy storage, characterized by quick response, flexible configuration, precise control and relatively friendly environment, is considered as the "best partner" for new energy power generation.

Wang said that it is foreseeable that in the future, the main types of batteries in the energy storage market will be large-capacity batteries with square hard shell and square soft package over 100Ah. lithium iron phosphate with silicon carbon anode is considered by the industry to be the mainstream material system in the future for a period of time.

As far as current technology is concerned, lithium ion battery is an ideal energy storage mode, which has distinct advantages over lead-acid battery and other energy storage technologies. However, both disposable lithium batteries and secondary lithium batteries contain a variety of metals as well as electrolytes, organic solvents and by-products produced during the battery cycle, which will cause pollution to the environment. To solve the problem of battery recycling as soon as possible has become an urgent task for the whole society.

The concept of battery cascade utilization has long been accepted in China. Although there is no complete application mode yet, its application prospect is still highly expected. Wang zidong believes that the key technology of recycling waste materials of lithium battery should be broken through the cascade utilization of the whole life cycle of the lithium ion power battery system, and the multi-level closed core components of the power battery system and the recycling system and recycling economy model of key materials should be established.

The goal of power battery recycling economy is to realize the low cost cascade utilization of power battery, lengthen the application chain, realize the decomposition and classification of materials without energy consumption and environmental protection, and achieve harmless recovery and material regeneration. Multi-stage utilization and recycling of power batteries are crucial, wang said, "not only for environmental protection, but also for the reuse of a profitable business model, which will affect the standard, performance, structure, production process and material system of power batteries worldwide."

Wang zidong pointed out that whether the power battery has the value of recycling, the first thing to do is to calculate the economic account, to advance the benefit of multi-stage use of the battery evaluation. In practical application, the recycling value of many materials is relatively low, especially the implementation of lightweight technology, which leads many enterprises to use non-metallic materials for battery box materials, so its value is even lower. For batteries such as lithium iron phosphate, the recycling value of positive electrode materials is not large, and the traditional recycling process will certainly lose money. Wang said that only after the "economic account" is calculated, can the next step of the process be considered.

According to wang, there are many difficulties in the low-cost cascade utilization of power batteries, mainly due to the battery product structure and production process. In order to improve the reliability of battery work, some enterprises adopt laser welding and other methods, which greatly increase the difficulty of battery cascade utilization. In addition, since different models have different battery pack designs, it is difficult to disassemble power batteries with a complete set of assembly lines after retirement, resulting in time-consuming and laborious disassembly. Even tesla, the world leader in electric cars, would struggle to dismantle its battery system, he said.

Wang stressed that the integrated design of power batteries is very important in order to achieve low-cost cascade utilization in the field of energy storage. In the design, the concept of "convenient repeated connection of battery structure, convenient system adjustment and maintenance, and hot plug and pull can be implemented" should be implemented. At the same time, it should be made clear that the physical decomposition efficiency of the non-crushing mode of power battery is much higher than the production efficiency. Therefore, non-comminution is a more economical method to decompose, while most of the recycling enterprises in the society use comminution method, which undoubtedly increases the cost of recycling.

He pointed out that the cost and profit problem is the main obstacle to battery recycling, recycling process cost is high, recycling value is low, so many enterprises and capital from. Therefore, "must develop low energy consumption, environmental protection material decomposition method." Wang stressed.

How to really solve the economic problem of power battery recycling? Zi-dong wang thinks "through the establishment of efficient and reliable lithium ion power battery system multilevel utilization and recycling system, reasonable share the use of lithium ion battery in the whole life cycle cost, make its in the whole life cycle, reduce the lithium ion power battery system directly on the cost of the application of the electric car industry, this is the most appropriate and effective solutions for now."

The page contains the contents of the machine translation.