EV batteries

Panasonic’s new US$4 billion battery factory in De Soto, Kansas, is designed to be a model of sustainability – it’s an all-electric factory with no need for a smokestack. When finished, it will cover the size of 48 football fields, employ 4,000 people and produce enough advanced batteries to supply half a million electric cars per year. But there’s a catch, and it’s a big one. While the factory will run on wind and solar power much of the time, renewables supplied only 34% of the local utility Evergy’s electricity in 2023. In much of the U.S., fossil fuels still play a key role in meeting power demand. In fact, Evergy has asked permission to extend the life of an old coal-fired power plant to meet growing demand, including from the battery factory. With my students at Wellesley College, I’ve been tracking the boom in investments in clean energy manufacturing and how those projects – including battery, solar panel and wind turbine...

The U.S. Environmental Protection Agency released strict new emissions limits on March 20, 2024, for cars built from 2027 through 2032. The final rule for Multi-Pollutant Emissions Standards caps a process that started almost a year earlier, when the Biden administration first proposed groundbreaking regulations that would essentially require automakers to make a substantial pivot toward electrification. The original proposal met significant pushback from carmakers and unions, who argued that the industry needed more time to switch from gas-powered cars to EVs. As a result, while the final target that this rule sets is very similar to the one that was initially proposed, the timetable in the final rule – especially in the earlier years – is relatively relaxed. That means more carbon emissions in the short run. Politics is inevitably an important consideration in regulating major industries. The new rule is projected to cut carbon dioxide emissions from passenger ca...

In a newly published study, we describe our design for a self-extinguishing rechargeable battery. It replaces the most commonly used electrolyte, which is highly combustible – a medium composed of a lithium salt and an organic solvent – with materials found in a commercial fire extinguisher. An electrolyte allows lithium ions that carry an electric charge to move across a separator between the positive and negative terminals of a lithium-ion battery. By modifying affordable commercial coolants to function as battery electrolytes, we were able to produce a battery that puts out its own fire. Our electrolyte worked well across a wide temperature range, from about minus 100 to 175 degrees Fahrenheit (minus 75 to 80 degrees Celsius). Batteries that we produced in the lab with this electrolyte transferred heat away from the battery very well, and extinguished internal fires effectively. We subjected these batteries to the nail penetration test, a common method for ass...

In today’s electronic age, rechargeable lithium-ion batteries are ubiquitous. Compared with the lead-acid versions that have dominated the battery market for decades, lithium-ion batteries can charge faster and store more energy for the same amount of weight. These devices make our electronic gadgets and electric cars lighter and longer-lasting – but they also have disadvantages. They contain a lot of energy, and if they catch fire, they burn until all of that stored energy is released. A sudden release of huge amounts of energy can lead to explosions that threaten lives and property. As scientists who study energy generation, storage and conversion, and automotive engineering, we have a strong interest in the development of batteries that are energy-dense and safe. And we see encouraging signs that battery manufacturers are making progress toward solving this significant technical problem. Avoiding overcharging is one way to reduce the ris...