Fire safety plays a key role in electric vehicles (EVs) as the market expands. EV batteries vary in chemistry and design, which affects their safety and failure modes. As a result, the materials used for EV battery fire protection must meet different requirements.

IDTechEx‘s report, “Fire Protection Materials for EV Batteries 2025-2035: Markets, Trends, and Forecasts,” predicts a 15% compound annual growth rate (CAGR) for these materials, with each battery having its own requirements and creating diverse material opportunities.

Types of Batteries and EV Battery Fire Protection Needs

The EV market primarily uses lithium iron phosphate (LFP) batteries, with lower energy density and cost, and nickel manganese cobalt (NMC) batteries, with higher energy density and cost. This distinction refers to the cathode, although many subsets and new variants continue to emerge. Future solid-state batteries, which replace the liquid electrolyte with a solid one, may increase energy density and potentially improve safety, though engineers must evaluate each chemistry individually.

Understanding the Likelihood of Thermal Runaway

Overcharging, overheating, internal short circuits, and mechanical damage can all cause thermal runaway. A manufacturing defect in any cell can trigger an internal short circuit and thermal runaway. LFP batteries provide more thermal stability than NMC batteries, making them less likely to overheat. Solid-state batteries, with no liquid electrolyte, also offer improved thermal stability.

Battery Temperatures and Gases During Thermal Runaway Events

The temperature at which a battery burns impacts the choice of protection materials. Studies show a link between burn temperatures and the energy density of the cell. Higher nickel content cells, like NMC 811, can reach temperatures of 800-900°C during thermal runaway, while LFP cells tend to stay below 600°C. Solid-state batteries can exceed 1500°C, depending on the specific battery type.

Batteries release gases during thermal runaway that can be flammable or toxic. Higher energy density batteries, like high-nickel NMC cells, release more gas volume than LFP cells. The gas composition varies: LFP batteries release more hydrogen, while NMC batteries release more carbon dioxide and carbon monoxide.

Summary and Outlook for EV Battery Fire Protection

Although EV fires remain rare, they still pose risks under specific conditions. With various battery types and chemistries on the market — and more in development — automakers must implement strong EV battery fire protection measures, according to IDTechEx. Manufacturers use materials like ceramic blankets, mica, aerogels, encapsulating foams, and intumescent polymers to prevent or delay thermal runaway propagation. Each battery designer must carefully consider the risk profile and structure of their battery system.

IDTechEx predicts a 15% CAGR for fire protection materials. The range of battery designs and chemistries presents major opportunities for companies that offer EV battery fire protection solutions in this growing market.