Brief description of low cost echelon utilization of power cells

At the "Energy Storage International Summit and Exhibition 2018(ESIE)" held recently in Beijing, Wangzidong, director of the China North Vehicle Research Institute and the National 863 power battery Testing Center, made "How to Build Energy Storage Industry into an Environmentally Friendly Industry". Keynote speech.

Wangzidong pointed out that our country is a large energy importing country, with more than 60 tons of primary energy imports, and energy strategic security has great risks. At present, China's power generation structure is not reasonable, and the proportion of thermal power is too large. "Improving the power generation structure and actively developing new energy and clean green energy power generation are undoubtedly urgent priorities. Electrochemical storage has the characteristics of fast response, flexible configuration, accurate control, and relatively friendly environment. It is considered to be the "best partner" for new energy power generation.

Wangzidong said that it is foreseeable that the main types of batteries in the energy storage market for some time to come will be large batteries with Square hard shells and square soft packaging of more than 100Ah. lithium iron phosphate and Silicon carbon negative electrode is considered by the industry to be the mainstream material system in the future period. The product adopts a flat roll and laminate process, which has the characteristics of safety, long life, and low cost.

As far as current technology is concerned, lithium-ion battery is an ideal energy storage method, and it has distinct advantages over lead-acid battery and other energy storage technologies. However, whether it is a disposable lithium battery or a secondary lithium battery, it contains a variety of metals and by-products produced by the electrolyte, organic solvents and battery cycle processes, which can cause pollution to the environment. To solve the battery recycling problem as soon as possible has become an urgent task for the whole society.

The concept of battery echelon utilization has long been accepted in China, and although it has not yet formed a complete application model, its application prospects are still highly anticipated. Wangzidong believes that through the full life cycle of the lithium-ion power battery system, it is necessary to break through the key technologies for the recovery of used materials of lithium batteries, and establish a multi-stage closed power battery system core components and key materials recycling system and circular economy. model.

The goal of the power cell cycle economy is to achieve low-cost echelon utilization of power cells, lengthen the application chain, achieve the decomposition and classification of materials that are inefficient and environmentally friendly, and achieve harmless recycling and material regeneration. Multi-level utilization and recycling of power batteries is crucial. Wangzidong pointed out that "not only for environmental protection, reuse of profitable business models will affect the standards, performance, structure, production processes, and material systems of power batteries around the world. "

Wangzidong pointed out that whether the power battery has a recycling value, first of all, the economic accounting should be calculated, and the benefits of multi-stage battery utilization should be evaluated in advance. Because in practical applications, the recycling value of many materials is relatively low, especially the implementation of lightweight technology, resulting in the use of non-metallic materials for battery box materials in many enterprises, its value is even lower. For batteries such as lithium iron phosphate, its positive material recovery value is not large, according to the traditional recycling process will certainly lose money. Wangzidong said that "economic accounting" after the calculation, can consider the next step in the process.

Wangzidong believes that the low cost of power cell echelon utilization is difficult. The main problem lies in the structure and production process of battery products. In order to improve the reliability of battery work, some enterprises use laser welding and other methods to greatly increase the difficulty of battery ladder utilization. In addition, because different models have different battery pack designs, power batteries are difficult to dismantle with a set of pipelines after decommissioning, resulting in time-consuming and laborious dismantling. Even Tesla, the world leader in electric vehicles, has a hard time dismantling its power cell system, he says.

Wangzidong emphasized that the integrated design of power cells is very important in order to achieve low-cost echelon utilization in the field of energy storage. At the time of design, it is necessary to implement the concept that "the battery structure should be easily connected repeatedly, facilitate system adjustment and maintenance, and can achieve thermal interpolation". At the same time, it also needs to be clear: the physical decomposition efficiency of the non-crushing mode of the power battery. It is much more efficient than production. Therefore, the use of non-comminuted decomposition is a more economical method. At present, most of the recycling enterprises in the society use a comminuted method, which undoubtedly increases the recovery cost.

He noted that cost and profitability were major barriers to battery recovery and that the high cost and low recycling value of the recycling process discouraged many businesses and capital. Therefore, "we must develop a low-energy and environmentally friendly material decomposition method. "Wangzidong stressed.

How can we really solve the economic problem of power cell recycling and reuse? Wangzidong 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.