Second life batteries refer to lithium-ion batteries that have been repurposed after their initial use in electric vehicles (EVs). While these batteries may no longer meet the demanding performance requirements for powering a car, they still retain a significant amount of energy storage capacity. Once an EV battery's performance degrades to a point where it can no longer efficiently power the vehicle, it's considered end-of-life for automotive use. However, these batteries are then collected and evaluated for their remaining capacity, and they are integrated into stationary energy storage systems. This article will discuss how they are repurposed and their applications.

How are the second life batteries repurposed?

Second life batteries offer a promising pathway to a more sustainable and efficient energy future. These devices are repurposed by being integrated into various stationary energy storage systems after undergoing the following main steps:

1. Battery collection and evaluation: EV batteries that have reached their end-of-life for automotive use are collected from various sources, such as dealerships, repair shops and recycling facilities. Each battery undergoes a thorough assessment to determine its state of health (SOH), remaining capacity and overall condition.

2. Formation or disassembling of battery module: In some cases, individual battery modules or packs with sufficient capacity are combined to form larger energy storage systems. For more complex repurposing, batteries can be disassembled to the cell level. Individual cells are then tested and sorted based on their performance, and then reassembled into new battery packs.

3. Integration into energy storage systems: Repurposed batteries can be combined to create large-scale energy storage systems that help balance electricity supply and demand on the grid. Smaller battery packs can be used for home energy storage, allowing homeowners to store excess solar power for later use.

4. Battery management systems (BMS): Repurposed batteries require advanced BMS to optimize performance, prevent overcharging or over-discharging and ensure safety. Continuous monitoring of battery performance is essential to track capacity degradation and adjust charging/discharging profiles accordingly.

What are the applications of second-life batteries?

Second life batteries, while no longer suitable for powering EVs, still possess significant energy storage capacity. This makes them valuable for a variety of applications:

1. Grid-scale energy storage

· Peak shaving: Storing excess renewable energy during off-peak hours and releasing it during peak demand periods.

· Frequency regulation: Balancing the grid's frequency by quickly adjusting power output.

· Voltage support: Maintaining stable voltage levels within the grid.

2. Residential energy storage

· Backup power: Providing electricity during power outages.

· Solar energy storage: Storing excess solar energy for later use.

· Time-of-use usage: Taking advantage of time-varying electricity prices.

3. Commercial and industrial applications

· Uninterruptible power supplies: Providing backup power for critical systems.

· Load leveling: Smoothing out electricity demand for commercial and industrial facilities.

· Microgrids: Supporting local energy generation and distribution.

4. EVs and marine applications

· EVs with reduced performance requirements: Golf carts, forklifts and other low-speed vehicles. For instance, golf carts typically require between 3 hp to 8 hp (2.2 kW to 5.9 kW) for electric models; forklifts need about 3 hp to 50 hp (2.2 kW to 37.3 kW) depending on capacity and features.

· Marine applications: Powering small boats and marine equipment. For example, small fishing boats may require between 5 hp to 20 hp equivalents for electric motors and larger boats could need anywhere from 20 hp to 100 hp equivalent or more for propulsion.

· Off-grid power systems: Providing electricity in remote areas.

Are there any other second-life batteries in addition to lithium-ion?

Currently, the predominant type of battery being repurposed for a second life is the lithium-ion battery. This is due to their widespread use in EVs, and their relatively high energy density compared to other battery chemistries. Other battery types, such as lead-acid or nickel-metal hydride, have traditionally been recycled or disposed of rather than repurposed due to lower energy density and shorter lifespan.

What are the benefits of second-life batteries?

· Environmental benefits: The environmental benefits of second-hand batteries are evident in both the extraction and disposal processes. A decrease in mineral extraction and an increase in resource conservation will prevent the continued loss of the Earth's minerals and prevent energy- and emission-intensive material processing. It also results in decreased environmental waste disposal and reusage of materials that have been recycled.

· Economic benefits: It starts a positive feedback loop of decarbonization and helps the energy transition forward by turning the cost of waste disposal into residual value, which in turn lowers the price of EVs.

· Energy storage: Provides a reliable and clean source of energy storage for various applications.

Conclusion

Recycled lithium-ion batteries are known as "second life batteries" because of their many uses after being used in EVs. These batteries are repurposed after careful evaluation and reconfiguration, and then integrated into stationary energy storage systems to extend their useful life and provide valuable energy storage solutions. Furthermore, proper handling and management of used batteries are crucial to prevent safety hazards.

To contact the author of this article, email GlobalSpeceditors@globalspec.com