Lithium-ion battery fires are a growing public safety concern − here's how to reduce the risk

• 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.

A new fire hazard

• As concerns grow in cities around the world about climate change and air quality, electric vehicles have taken center stage.
• At the same time, e-bikes and electric scooters are transforming urban transit by providing convenient, low-carbon ways to navigate crowded streets and reduce traffic congestion.
• Fire departments in New York City and San Francisco report handling more than 660 fires involving lithium-ion batteries since 2019.
• Clearly, there is a need for safer handling and charging practices, as well as technical improvements to batteries.

Many batteries in an EV

• A battery holds chemicals that contain energy, with a separator between its positive and negative electrodes.
• Depending on its design, an EV may contain dozens to thousands of single batteries, which are known as cells.
• A standard EV will contain one large battery pack with many cells inside it.

What causes battery fires

• Typically, a battery fire starts in a single cell inside a larger battery pack.
• Battery short circuits may be caused by faulty external handling or unwanted chemical reactions within the battery cell.
• Another factor that makes lithium-ion battery fires challenging to handle is oxygen generation.
• Fires need oxygen to burn, so a battery that can create oxygen can sustain a fire.

Managing the thermal runaway problem

• However, these mechanisms make the battery larger and heavier, which can reduce the performance of the device it powers.
• And they may not be reliable under extreme temperatures or pressures, such as those produced in a car crash.
• Making a thermal runaway in a battery pack less intense requires a mix of software and hardware improvements.
• Park the vehicle away from extremely hot or cold surroundings – for example, park in shade during heat waves – to prevent thermal stress on the battery.