One cell away from disaster: Why EV battery design could determine safety

Thermal incident risks linked to battery cell design, 24M Technologies says

24M Technologies has reported that thermal incidents are expected to increase as global electric vehicle (EV) numbers rise and battery energy density continues to grow.

The company cited forecasts projecting the global EV fleet to reach 250 million by 2030, up from around 40 million today.

According to 24M Technologies, some markets have already experienced a 33% increase in thermal incidents involving EVs.

It stated that while these events remain rarer than fires involving internal combustion engine (ICE) vehicles, they often pose greater risk, particularly when vehicles are stationary or charging.

The company warned that even if thermal incidents occur in just one of every 10,000 EVs, the annual total could reach 25,000 worldwide by the end of the decade.

Battery energy density and fast charging identified as major factors

24M Technologies stated that growing energy density, which helps increase range and boost EV adoption, also reduces the safety margin within battery cells.

The company added that manufacturing processes cannot eliminate risks such as contamination, which can contribute to thermal events.

It reported that internal short circuits are especially dangerous, as they are difficult to detect externally and can trigger overheating.

Naoki Ota, President and CEO at 24M Technologies, said: “The industry’s current safety challenges stem from decades-old battery design principles.

“While we’ve achieved remarkable progress in cost reduction and energy density, we’re still building upon architectures that have not fundamentally changed in more than 30 years.

“Process improvements alone cannot address these design limitations and multiple OEMs have faced costly recalls as a result.

“Rather than address these issues through add-on system features, safety must be incorporated as a foundational element at the core of the battery cell.”

24M Technologies noted that recalls related to EV fires can cost up to $1 billion per vehicle model line, putting financial pressure on manufacturers.

Dendrites and thermal runaway pose long-term fire hazards

The company reported that dendrite growth, which can occur during repeated charging cycles or due to fast charging at low temperatures, is a major risk factor for thermal incidents.

It explained that dendrites can cause short circuits and lead to thermal runaway, a process where a battery cell overheats and releases flammable gases.

24M Technologies stated that thermal runaway can happen in milliseconds and may spread to adjacent cells and the vehicle itself.

It added that once a thermal event begins, it cannot be stopped without intervention.

Naoki Ota continued: “The solution is to incorporate transformative in-cell fire prevention technology.

“24M’s pioneering Impervio system is uniquely capable of suppressing dendrites and neutralising thermal runaway before it can start.

“Unlike other technologies, Impervio not only monitors individual cells but prevents thermal incidents.

“The industry must shift from reactive measures to try to contain fires to proactive designs preventing failures before they occur.

“Without this step change approach, the safety and financial challenges will only intensify as EV adoption accelerates.”

Impervio technology designed to mitigate cell failure risks

24M Technologies stated that its Impervio technology aims to prevent thermal incidents by suppressing dendrite growth and detecting faults at the individual cell level.

Ulrik Grape, President, European Operations, at 24M Technologies [pictured] said: “Impervio offers a proactive solution for the world’s car makers, fundamentally changing how battery safety is approached through revolutionary new battery cell design.

“Controlling the cell at the individual electrode level, the Impervio separator actively suppresses dendrite growth within cells while enabling sophisticated monitoring capabilities for early fault and short-circuit detection.

“It can shut down a cell that is at risk – monitoring, preventing, containing – and represents a step change in safety while offering the capability to massively reduce risk and financial exposure.”

In a test, 24M compared two NMC/graphite cells charged to 100% and then overcharged.

The cell without Impervio developed dendrite-induced shorts after 15 minutes and exploded after 38 minutes.

The Impervio-equipped cell remained stable, with no short or fire after an hour of overcharging.

EV safety challenges linked to infrastructure and recall complexity

24M Technologies noted that although EVs are 20 times less likely to catch fire than ICE vehicles, thermal incidents often occur when vehicles are parked or charging.

It stated that such fires are difficult to extinguish due to internal chemical reactions and may reignite after hours or days.

The company explained that this creates challenges in buildings such as car parks, apartment blocks and shopping centres.

It added that Impervio technology supports targeted recalls, enabling manufacturers to isolate specific faulty units rather than entire vehicle lines.

24M Technologies stated that Impervio is compatible with lithium-ion, lithium metal and its proprietary LiForever cell platforms.

It reported that the technology can also improve state-of-health and end-of-life predictions, supporting battery reuse strategies.

The company confirmed it is working with several car makers and partners to integrate the system into future designs.

Thermal incident risks linked to battery cell design, 24M Technologies says: Summary

24M Technologies has warned that thermal incidents in electric vehicles are likely to increase as EV adoption and energy density grow.

The company cited data showing a 33% increase in thermal incidents in some markets.

It projected a potential global total of 25,000 EV fires per year by 2030.

Internal short circuits and dendrite growth were identified as key causes of thermal runaway.

24M stated that safety challenges stem from battery designs that have changed little in 30 years.

CEO Naoki Ota said a new approach is needed that addresses safety at the cell design level.

Impervio, the company’s in-cell safety system, aims to prevent dendrite formation and thermal runaway.

Testing showed Impervio cells withstood overcharging without catching fire.

The technology allows for continuous monitoring and cell-level shutdown to isolate faults.

It is compatible with existing lithium battery formats and 24M’s own LiForever cells.

The company stated that Impervio may help reduce recall costs by targeting only affected batteries.

24M is collaborating with car makers to integrate Impervio into next-generation batteries.