Explore low cost echelon utilization model of power battery to build up green energy storage industry

At the recent "energy storage summit and exhibition 2018 (ESIE)" held in Beijing, 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 dependent on imports, and energy strategic 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 square hard shell and square flexible package batteries with a capacity of 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. The product adopts the technology of flat coil and lamination, which has the characteristics of safety, long life and low cost.

In terms of current technology, lithium ion battery is an ideal way to store energy, 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 a complete application mode has not been formed yet, its application prospect is still highly expected. According to Wang zidong, the key technology of recycling waste materials of lithium batteries should be broken through the full life cycle of lithium ion power battery system, and the multi-level closed core components of power battery system and the recycling system and recycling economic 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 recycling treatment and material regeneration. Multi-stage utilization and recycling of power batteries are crucial, Wang said, "not only for environmental protection, but also for 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 anode materials is not large, and the traditional recycling process will certainly lose money. Wang said that the "economic account" after the calculation, can consider the next step of the process.

According to Wang, the low cost cascade utilization of power batteries is difficult, and the main problem lies in the battery product structure and production process. In order to improve the reliability of battery pack, 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 the power batteries with a complete set of assembly lines after retirement, resulting in time-consuming and laborious disassemble. Even Tesla, the world leader in electric cars, would struggle to dismantle its battery systems, he said.

Wang stressed that the integrated design of power batteries is very important to realize the 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 realized" 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 manufacturing 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 problem of cost and profit is the main obstacle to battery recycling, recycling process cost high, low recycling value, so that many enterprises and capital from. Therefore, "must develop low energy consumption, environmental protection material decomposition method." Prince dong emphasized.

How can we really solve the economic problem of power cell recycling and reuse? Wang zidong believes that "by establishing an efficient and reliable multistage utilization and recycling system for lithium-ion power battery systems, the cost of using lithium-ion batteries in the full life cycle is reasonably shared so that it is within the full life cycle. Direct reduction of the cost of lithium-ion power battery system in the electric vehicle industry is the most suitable and effective solution. "

The page contains the contents of the machine translation.