Battery Safety in the Modern Era

It’s hard to go more than a few minutes without using something that requires a battery, whether it’s your smartphone, car or a pair of wireless headphones. Many of these power sources are lithium-ion batteries. Using a battery for energy is generally safe, but these components are still prone to explosions and fires. Here are some examples of research that’s pushing lithium-ion battery design and other relevant progress forward.

Making Lithium-Ion Batteries Cathodes With Safer Minerals

Some safety concerns linked to lithium-ion batteries arise from the instability of components necessary to make them, including substitutes for minerals that are increasingly scarce or located in conflict zones. Such is the case with nickel cathodes, which engineers often swap out for cobalt ones. The latter is increasingly challenging to source. However, cathodes with high nickel contents have mechanical and thermal instabilities that make them less safe.

A research team recently used a technique called high-entropy doping to create a layered, cobalt-free cathode that showed extremely high heat tolerance and stability during repeated charge and discharge cycles.

Huolin Xin — a physics and astronomy professor who worked on this project — explained that electric vehicle manufacturers want to reduce cobalt in their batteries for a few reasons. The first is they’re aware of the child labour used to mine the minerals. Secondly, minimizing cobalt could help them cut costs. The mineral has safety concerns, too — Xin explained cobalt could release oxygen at high voltage, which could damage the batteries.

Making lithium-ion batteries with nickel-based cathodes is also not ideal. Battery material oxidation is more likely due to nickel’s low heat tolerance. Then, thermal runway events or explosions become greater risks. Additionally, high-nickel cathodes repeatedly expand and contract, which can cause strain that reduces stability. Together, these factors illustrate the urgent need for lithium-ion battery design improvements.

The researchers’ innovation involved mixing in several other elements. The inside of the cathode included magnesium, titanium, manganese, molybdenum and niobium. There was then a subset of those minerals on the cathode’s surface. Tests showed this cathode could handle more than 1,000 charge cycles. The team hopes this work is a step toward safer, more sustainably sourced options.

Reducing Fire Risks

Electric cars require people to establish new habits, such as remembering to plug in the vehicles rather than relying on the nearest gas station. Regardless, using these cars is increasingly convenient. Superchargers from Tesla only need about a half hour to fully charge the vehicle.

However, an overall downside of electric vehicles is that they pose additional challenges — such as toxic fumes and high-voltage wires — to the firefighters called if those cars catch on fire. Researchers are interested in how to make fires less likely. Succeeding would make the vehicles more attractive to consumers while reducing prevalent dangers firefighters face.

Probing What Happens If Battery Fires Occur in Various Spaces

A team used simulations inside a Swiss test tunnel to determine what happened when electric vehicle batteries caught fire in tunnels, underground parking garages and other structures. Their findings will be instrumental in helping engineers improve lithium-ion battery design.

For example, the researchers set fire to battery cells in ventilated tunnels, enclosed spaces and rooms with sprinkler systems. They then examined the spread of soot, smoke gases and chemical residues in the water used to extinguish the blazes.

These tests revealed important takeaways that impact several industries. The water used to extinguish the test fires contained up to 100 times above threshold levels of contamination. Thus, the researchers cautioned this water must get treatment before entering the sewage system. Additionally, the soot contained heavy metals that could cause allergic reactions on unprotected skin.

This work will also be important for determining the impact of battery fires in densely populated areas. There were more than 60 lithium-ion battery fires and five fatalities in New York City during the first half of 2023. Another instance in the area led to the lithium-ion battery for a micromobility device resulting in a nearby apartment building fire. The more aware people become of such ramifications, the easier it’ll be to justify prioritizing lithium-ion battery design enhancements for better safety.

Creating a Lithium-Ion Battery Design That Stops Fires

Lithium-ion batteries have electrolyte liquid separating the electrodes. However, when the batteries get too hot, it can evaporate, causing short circuits. Short-circuiting can also trigger thermal runaway events. The issue can worsen in applications like electric vehicle batteries, which often have multiple linked cells that thermal runaway events can spread between.

Lithium-ion battery design features like sensors and vents can reduce the thermal runaway probability, but they often reduce performance. Researchers wanted to make batteries safer without compromising their performance. Thus, they covered a thermally responsive shape-memory polymer with a conductive copper spray.

That approach made a material that transmitted electrons normally unless it became abnormally hot. If that happened, it would switch from a transmitter to an insulator. That shift happens at approximately 197° Fahrenheit due to a microscopic pattern that splits the copper layer, stops the electron flow and prevents a fire.

This invention had a similar cycle life span to conventional batteries and was highly conductive with low resistivity. It could create a foundation for further work that results in high-performing, safe batteries.

Safer Batteries Are Essential

Batteries are so widely used in modern life that any progress in making them safer is notable. It’s also positive that people are taking various approaches to improving safety. Many are still in the early stages, and the things researchers learn now will help them and others make better decisions for similar, future work.

Relatedly, safety enhancements in lithium-ion battery design will positively impact consumers. Even if they don’t see or know the details that make the power sources less likely to catch fire or explode, they’ll appreciate the reduced risks when using the products.

Most people use so many battery-powered devices daily that they hardly think about the minimal —  albeit present — safety risks. However, injuries, property destruction and deaths result when things go wrong. The world’s battery dependence is only growing, so safety-centric developments are critical for a safer future.