Electric vehicles (EVs) are becoming more common on roads around the world. As more people switch to EVs, the number of batteries reaching the end of their useful life in vehicles is also increasing. These used batteries are no longer good enough for cars but still hold up to 70–80% of their original storage capacity. Instead of throwing them away, these batteries can have a second life in energy storage systems, especially for solar power.
One of the most promising uses of second-life EV batteries is in storing solar energy. Solar power is clean and renewable, but it depends on sunlight, which is not available all the time. During the day, solar panels often generate more power than needed. That extra power can be stored in batteries and used later when the sun is not shining. This is where second-life EV batteries come in. They offer an affordable and sustainable way to store energy without the need to build new batteries from scratch.
Using second-life batteries helps reduce the cost of solar-plus-storage systems. New lithium-ion batteries are expensive, but reused EV batteries cost much less. This makes it easier for homes and businesses, especially in rural and remote areas, to afford backup power systems. Countries like India, where solar energy is growing fast, can benefit a lot from these lower-cost storage options.
Second-life batteries also help reduce electronic waste. If old EV batteries are reused, fewer batteries end up in landfills, which is better for the environment. It also means fewer new resources are needed to build fresh batteries, reducing the demand for mining materials like lithium, cobalt, and nickel.
Some companies are already working on ways to collect, test, and repurpose used EV batteries. They check the battery’s health, remove damaged cells, and rebuild battery packs for new use. These refurbished battery packs can be installed in homes, office buildings, schools, or even small solar-powered grids in villages.
There are some challenges too. Second-life batteries must be tested carefully to make sure they are safe and reliable. Different batteries from different car models have different sizes and chemistries, which can make standardizing systems harder. Also, policies and safety rules are still being developed in many countries to guide the reuse of EV batteries.
Despite these challenges, the idea of using EV batteries after their road life is gaining attention from researchers, governments, and industries. It is a win-win solution—supporting clean energy, reducing waste, and making solar storage more affordable. With the right systems and support, second-life batteries can play a big role in powering homes with solar energy, especially in places where energy access is still a problem.
In the coming years, as EV adoption increases, so will the supply of used batteries. This presents a big opportunity to build a circular economy where old batteries do not become waste but instead power a greener future. From road to roof, second-life EV batteries can make a real difference in making clean energy reliable and affordable for all.
