Dyness Knowledge | Solar and energy storage must-learn terminology(Cascade utilization of power battery)

With the rapid development of the electric vehicle market, the demand for power batteries is also increasing. The data shows that the global installed capacity of electric vehicle power batteries will be about 517.9GWh in 2022, a year-on-year increase of 71.8%. It is estimated that the global power battery installed capacity will reach 762GWh in 2026. However, when these batteries reach a certain useful life, they are retired and can no longer be used in electric vehicles. In order to maximize the value of batteries, the cascade utilization of power batteries has become a new research hotspot.

The cascading utilization of power batteries mainly refers to: when the capacity of power batteries is reduced to below 80%, and it is difficult to meet the needs of new energy vehicles, the "decommissioned" batteries are screened and recycled. And reapply to mild application scenarios such as peak shaving and valley filling, backup battery, etc.

(Image source: bilibili, Talking Today, "Research Status and Development Direction of Cascade Utilization Technology of Power Batteries")

The advantages of cascade utilization of power batteries are mainly reflected in the following aspects.

1. Environmental protection: through cascade utilization, the service life of the power battery can be extended and the pollution to the environment can be reduced.

2. Maximization of resources: Cascade utilization can maximize the value of batteries and avoid waste of resources.

3. Economical: Through the cascade utilization of power batteries, the production cost of batteries can be reduced and economic benefits can be improved.

The path selection of power battery cascade utilization is a complex issue, which needs to comprehensively consider multiple factors such as safety, reliability, and economy. At present, there are two main paths for cascade utilization of power batteries, the distributed path represented by telecall and the large-scale path represented by battery recycling companies.

The distributed path refers to maintaining the original form of the power battery, using the whole package, and using the power battery in the nearest cascade after it is decommissioned from the electric vehicle. In terms of safety, the distributed path disperses the batteries to various places, reducing the cost and risk of transportation and management. The battery utilization points are small and scattered, which makes it easier to maintain and supervise the battery and reduce safety risks. From the perspective of economy, distributed paths can be carried out on a smaller scale, with small initial investment and low operating costs. And because the power battery is not unpacked, the problem of the consistency of the echelon battery is solved economically and effectively.

Distributed power battery cascade utilization is currently mainly used in industrial parks or charging stations as cascade battery energy storage boxes to achieve the purpose of peak-shaving and valley-filling or peak-valley arbitrage.

The path to scale refers to the unpacking of decommissioned power batteries, performance evaluation, battery sorting, and system integration of the batteries. The path to scale can realize the centralized management and maximum utilization of batteries, and improve the utilization rate and economic benefits of batteries. The large-scale path has high technical content. Although the initial investment is large, compared with the standardized path, various resources can be better integrated, and the economic benefits in the later stage are more considerable.

Scale power battery echelon exists in the form of battery recycling companies such as Tesla recycling factories, which unpack power batteries, perform performance evaluation, battery sorting, and system integration to maximize resource utilization.

Both technical paths are not perfect, although the distributed path can largely guarantee the safety and stability of the power battery cascade utilization process. However, due to the scattered investment, a lot of manpower and material resources are needed. Although the large-scale path can maximize the utilization of decommissioned power batteries, the initial investment is large and the risk of centralization is high, which poses a big challenge to production safety.

At present, China's power battery cascade utilization is still mainly distributed. Mainly due to safety considerations, the safety of large-scale lithium battery energy storage has yet to be resolved.