Giving high voltage batteries a second life

Everyone deserves a second chance - even high voltage batteries! The shift toward electric vehicles (EVs) is putting more batteries on the road than ever before. But what happens when their capacity diminishes? Instead of being discarded, these batteries can serve new purposes, proving that sustainability and innovation go hand in hand.

Why do EV batteries lose capacity?

Modern electric vehicles use lithium-ion cells, which degrade over time. And as storage capacity shrinks, driving ranges get shorter. However, even when an EV battery no longer operates efficiently in a vehicle, it still holds 70-80% of its original energy capacity, making it far from useless.

Repurposing batteries for stationary storage

Instead of discarding batteries, they can be reused in stationary energy storage devices. Stationary use is significantly milder than car use, which subjected batteries to fast charging, discharging, and regenerative braking. They gradually release energy, making them perfect for balancing electrical supply and demand.

HV batteries that have been mustered out from vehicles because their capacity is too low do not become useless or worthless as a result. When these energy storage units are removed from vehicles, they normally have a capacity of around 70-80% of their original energy content. Despite the fact that the capacity of these batteries is no longer enough to use them in vehicles, disposing of them makes neither ecological nor economic sense. These high voltage batteries can continue to be used in a stationary setting in their second life.

For example, in Wendelstein, Germany, decommissioned Audi test vehicle batteries have been reused as a storage facility. Two air-conditioned containers house 84 battery units, which provide one megawatt-hour (1000 kWh) of storage - enough to power 100 houses for a whole day.

How second-life batteries benefit renewable energy

Battery storage is critical to the electricity grid's stability. On bright or windy days, solar and wind farms frequently produce more electricity than is required. Instead of wasting excess electricity, second-life batteries store it and release it when need increases. This contributes to the development of a more reliable and sustainable energy system.

Recycling batteries after their second life

When EV batteries reach the end of their useful life, recycling ensures that important materials are not lost. There are two basic methods for recovering raw materials:

1. Thermal processing (melting the batteries down)
   • Separates metals based on melting points
   • Recovers cobalt, nickel and copper
   • Lithium is extracted in an additional step
   • Average recycling efficiency: 60-70%, with cobalt and nickel at 95%
2. Mechanical shredding (breakdown of components)
   • Batteries are shredded in an enclosed container filled with nitrogen to prevent ignition
   • Extracts aluminium, copper, graphite, manganese, nickel, cobalt, and lithium
   • Has a 96% recycling rate, making it a more sustainable option

The future of battery innovation

High voltage batteries have a purpose even after they have left the road, thanks to second-life applications and innovative recycling processes. As technology advances, new advancements may prolong battery life cycles even further. The future of energy is about more than just producing power; it is also about using it more efficiently.