Have you ever noticed when your smartphone gets unusually warm? Warm is not abnormal for smartphones. After all, a discharging battery produces heat as a byproduct of electron flow. Apps can also cause warming, for example, gaming, video streaming, GPS navigation, and camera use.
Lithium Batteries Are Everywhere
Lithium-ion batteries are used in electric vehicles (EVs), 70% of the total by energy capacity, in stationary energy storage, 15%, and in portable electronics, 5%. That latter percentage includes smartphones. Usage since 2020 has increased 600%.
In 2024, consumer electronic devices containing lithium-ion units equalled 1.2 billion units, of which 45% were smartphones, 30% laptops, 15% tablets, and 10% wearables.
That’s a lot of batteries that, over time, can begin to degrade. It’s also a growing fire threat.
Two Personal Lithium-Ion Overheating Stories
Several years ago, my wife’s Samsung smartphone began showing sporadic changes in retained charge. Overnight, while plugged in, the phone got hot and the back, where the battery’s anode was located, separated from the screen, producing a visible gap.
A second smartphone saga happened recently while I was on vacation. This time, it was my Google Pixel 7a that suddenly lost its charge. It got hot and then cooled down. I left it plugged in overnight to recharge. In the morning, the phone’s back casing had cracked, leaving two large bumps.
Why are smartphones powered by lithium-ion batteries potentially susceptible to overheating? The phones are thin and have a small form factor. There is little room to dissipate the heat. A 2021 CBC News report noted that smartphones topped the list of fires caused by electronic devices. A 2025 ABC News item reported 25,000 runaway overheating and fire incidents in smartphones over 5 years. That same story mentioned U.S. product safety agencies reporting increasing incidents of household fires from smartphone batteries or chargers overheating.
The Lithium-ion Thermal Runaway Problem
When lithium-ion batteries age or get damaged, a chain reaction can start, with the batteries reaching hundreds of degrees Celsius during incidents. What’s happening to cause this? As the batteries age, the anodes can produce surface dendrites, akin to the stalactites seen in limestone caves. Instead of these growths being made of calcium carbonate, the ones batteries produce are stray lithium filaments, which form unevenly on the anode surface as hot spots form. Phone use, particularly apps that are energy-intensive, causes the dendrites to grow. They can get so large that they penetrate the interphase layer that separates the anode from the battery cathode. That leads to short circuits, sudden battery discharge, and in some cases, runaway overheating.
A recent report from Argon Electronics, a United Kingdom company that creates training simulators focused on first responders when handling hazardous chemical, biological, radiological, and nuclear material threats, states:
“When lithium-ion batteries fail, they don’t follow the usual script. They behave differently, and that’s where the risk starts to build.”
With the growth in lithium-ion battery use, Argon sees an increased need for its simulators to train clients about these types of fires. The latest press release describes the onset of a lithium-ion runaway event:
“It usually doesn’t begin with anything dramatic. A hiss. Maybe a sharp pop. Sometimes just a thin plume of grey-white smoke from something that, at first glance, doesn’t seem capable of causing much trouble. Then the temperature climbs. Gases begin to build. And what you thought you were dealing with a moment earlier shifts into something else entirely, often before anyone has had time to take stock.”
Felipe Arrighi, Director of Business Development at Argon, states:
“People still tend to frame these as ‘just fires,’ and they’re not. Once thermal runaway starts, you’re dealing with gas release, pressure, sometimes reignition. It behaves differently, has a life of its own. If you haven’t seen it before, it can throw you.”
What gas can come from a lithium-ion fire? Runaway overheating can produce hydrogen fluoride and carbon monoxide, along with fire and smoke. In enclosed or poorly ventilated spaces, these elements are life-threatening.
Only recently have regulations started to catch up in recognition of the growing volume of lithium-ion battery usage. In the United States, the US National Fire Protection Association has added new standards for firefighters, placing a greater emphasis on gas monitoring and detection. Typically, training videos are circulated. Arrighi explains that videos don’t cut it. He notes:
“You’re not making decisions, you’re not reading your detectors, you’re not dealing with the pressure of it, developing your sense of situational awareness or muscle memory. That’s the bit that stays with you.”
Why Simulators Make a Difference
If you remember Apollo 13, you can appreciate the importance of using simulations for training, particularly when a crisis unfolds. Even though the scenario had never been anticipated, in the case of the Apollo astronauts, replicating what they faced on board allowed NASA to improvise several solutions to save the mission from disaster.
In that tradition, Argon is creating simulators to create scenarios as close to real as possible for training people down here on Earth when responding to hazards, including lithium-ion combustion threats. The Argon simulators build familiarity to address whatever happens in real-world situations. Argon’s Long Range Vapour Sources (LRVS) simulates gas release and dispersion. And while no simulation can perfectly replicate what a lithium-ion fire produces, the LRVS comes as close to anything responders will face in the field.
Some Argon users have even used lithium battery scenarios to simulate battery leaks, producing thermal imaging heat signatures. These scenarios, combined with Argon’s Generic MultiGAS, create highly realistic and memorable training experiences.
Lithium-Ion Market and Future Demand
Lithium-ion batteries aren’t going away. Demand is projected to rise for the following reasons:
- The move away from fossil-fuel-powered transportation to electric mobility, with more lithium-ion battery packs on the move, presents many different scenarios to consider.
- The growth in demand for distributed energy, solar rooftop and battery energy storage systems will lead to installations in a wide range of home and building scenarios.
- The continued growth in the use of consumer electronic devices and wearables powered by lithium-ion batteries will put more batteries out there in public and domestic spaces.
Asian-based companies dominate lithium-ion battery manufacturing, with China representing 75% of the total EV battery market today. The remainder in Asia comes from South Korea and Japan. In North America and Europe, Tesla and other automotive manufacturers represent the majority of lithium-ion battery manufacturers and integrators.
Less-established Chinese suppliers present potential quality risks as these companies have sprung up in response to lithium-ion battery demand. The biggest issues relate to undisclosed material changes during manufacturing.
Many consumer electronics and EV battery recalls have happened because of the high demand and high growth of the lithium-ion battery market. Hence, there is a commensurate need for greater training for emergency responders who will likely see far more lithium-ion fires in the future.
