Cone Calorimeter
A Cone Calorimeter is one of the most widely used instruments in fire testing to study the combustion behavior of materials. The cone calorimeter measures how materials ignite and burn under controlled heat flux conditions. It helps quantify heat release rate (HRR), which is the most important parameter in fire science because it determines fire growth and intensity.
A conical-shaped radiant electric heater delivers a controlled external heat flux. The material is ignited, and the combustion gases are collected through an exhaust system where oxygen consumption calorimetry is applied.
The test measures the following parameters:
- Heat Release Rate (HRR) using Oxygen consumption calorimetry
- Mass loss rate
- Smoke production rate
- CO/CO2 production rates
- Time to Ignition
Primarily it was developed to measure fire properties of combustible materials, including plastics, wood, fabrics, and polymers but now it is also used to measure the fire behavior of lithium-ion or other batteries under external radiant heat flux.
Applications of Cone Calorimetry for Batteries
- Compare flammability of different battery chemistries (NMC vs. LFP, etc.).
- Study influence of state of charge (SOC) on fire severity.
- Evaluate battery enclosures, fire barriers, or thermal protection materials.
- Generate data for fire models (CFD, hazard simulations).
- Safety validation in industries: EVs, aerospace, energy storage systems (ESS).
- Material selection for casings, separators, and electrolytes
Standards / References:
ISO 5660-1 “Reaction-to-fire tests — Heat release, smoke production and mass loss rate”
ASTM E1354 “Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter”
Equipment used:
• Cone Calorimeter
FAQ:
1. Why use Cone Calorimetry for batteries?
It simulates how batteries behave in an external fire scenario. This includes ignition, heat release, smoke, and toxic gas emissions, which are critical for EVs, aerospace, and energy storage safety.
2. What sizes of batteries are tested?
- Individual cells (cylindrical, prismatic, pouch)
- Small battery modules
- Packs (with special containment and safety measures)
3. What heat flux levels are typically used?
- 25–75 kW/m² for external fire exposure simulations
- Sometimes higher (up to 100 kW/m²) for severe fire conditions
4. How is ignition initiated?
Usually by the external radiant heat from the cone heater. If the battery vents but doesn’t ignite, a pilot flame or spark igniter may be used.
5. How does this differ from ARC test?
- Cone Calorimeter → Studies external fire exposure: how a battery behaves when subjected to radiant heat or flames.
- ARC → Studies intrinsic thermal stability: how a battery behaves when it self-heats and goes into thermal runaway without external fire.
So, cone calorimetry is excellent for external fire exposure testing of batteries (how a battery behaves when caught in a fire), but not ideal for intrinsic thermal runaway onset characterization — that’s where ARC is better.