More focus on battery explosions

Battery fires and explosions are a serious issue we should deal with. Because the number of batteries is increasing. Consequently, DBI is involved in a new project to create new knowledge of the field and to make recommendations to emergency response teams.

Using batteries is becoming more popular. Electric cars, electric bicycles, electric motorbikes/mopeds and electric scooters – it is simply the age of the lithium-ion battery. The risk of fire in lithium batteries is statistically low, but if it happens, fires can be both complicated and take a long time to extinguish – and in the worst case develop into an explosion.

The number of lithium-ion batteries being used is increasing as they are an element in more and more products and in means of transport. Some of them go through a recycling process in order to recycle the metals in new batteries, others are refurbished (repaired and checked) and reused, while others again – unfortunately – are sold and reused on an unregulated second-hand market.

“These second-life batteries are potentially problematic because they may be worse for wear, not maintained or damaged. This changes the chemical processes in the batteries so they have lower performance and maybe higher heat generation. They are more unpredictable, such as thermal runaway, which can lead to fire or explosion,” explains Agata Gallas-Hulin, Research Consultant at DBI – The Danish Institute of Fire and Security Technology. She continues:

“The risk is further increased if they are used in a context other than originally designed for and without the right battery control software. For example, this may be for battery storage systems in private homes with solar cells or a domestic wind turbine”.

BESAFE

This problem is the background for a new project in which DBI, together with RESC Centre for Rescue and Safety, Hovedstadens Beredskab (Capital City’s Emergency Management), the recycling company Stena Recycling, the National Research Centre for the Work Environment, Lund University and Aarhus University, will gain new knowledge about battery fires and explosions. The existing strategies for fighting battery fires must be evaluated, and recommendations must also be prepared for emergency response, which will initially be in place in the event of a battery fire.

The name of the project is BESAFE, where the name is a contraction of Battery Explosion Safety. There are several examples of battery fires worldwide that have led to explosions, and the Danish project is inspired by a commercial DBI test at the RESC Centre for Rescue and Safety at the Danish town of Korsør. Here, electric cars exploded twice because fumes, accumulated in the cabin from a provoked thermal runaway in the battery, were ignited. In both cases, the explosions caused considerable material damage to DBI’s test facilities.

And the incidents are not unlike what can happen in private homes.

“It is a major and real concern for the emergency services that unstable batteries find their way into private homes where the firefighters are not prepared to handle the situations,” says Agata Gallas-Hulin, adding:

“Imagine that as a firefighter you arrive at a fire scene, such as a garage or a room in a house, and open the door without knowing that the fire involves a battery. The battery may have been in thermal runaway, which has released toxic and flammable gases that accumulate in the room. All that is needed to create an explosion is the supply of oxygen from the open door.

Specific recommendations for emergency response teams

The project is structured around three series of tests. In the first test, DBI will investigate the condition of various lithium-ion batteries supplied by Stena Recycling and define the critical parameters for a battery explosion. In this connection, DBI will also analyse the gases – both quantity and composition – that are released during thermal runaway.

According to Agata Gallas-Hulin, these tests will primarily be carried out as small-scale tests at DBI and lead to the next series of large-scale tests in Korsør, where the effect of different ventilation conditions on the accumulation of gases and the risk of explosion will be tested. This will be done by placing one battery system with thermal runaway in a closed chamber with a safety valve, one in a chamber with room ventilation according to building regulations and one in a chamber with an opening like an open door.

Based on the results of the first two test series, an international panel of advisory experts will make recommendations on which battery fire fighting strategies should be tested and evaluated on a full scale in the third and final test series. Here, battery systems will be placed in an environment similar to a typical room in a house. The temperature, pressure and heat generation will be measured, and a video will also be recorded as firefighters fight the fire.

“These tests should determine the impact of different strategies under different conditions and identify the tactical considerations that firefighters who are first at the fire scene should make. All of this is summarised in a report that provides specific recommendations for the emergency services,” says Agata Gallas-Hulin, pointing out two things that make the project particularly interesting for DBI:

This is the first time that we have such an extensive advisory board of international experts in a project. After the project, DBI will also have test facilities and a test protocol to test and analyse the fire risk of lithium-ion batteries,” says Agata Gallas-Hulin.

Read also: ELBAS: Possible to safeguard ferries against electric car fires and Suppression system for electric vehicle fires in multi-storey car parks shows promising results

BESAFE

BESAFE is a multi-year, self-financed project in which DBI, RESC Centre for Rescue and Safety, Hovedstadens Beredskab, Stena Recycling, the National Research Centre for the Work Environment, Lund University and Aarhus University will gain new knowledge about battery fires and explosions, evaluate the existing strategies for fighting battery fires and make recommendations to the emergency response management, which will initially be in place in the event of a battery fire.

Together with Hovedstadens Beredskab, DBI is responsible for the design of the project, just as DBI must also design and perform tests, carry out data analysis, compile and consult with a panel of international experts and prepare the project report. Anders Drustrup and Agata Gallas-Hulin from Advanced Fire Testing, Elena Funk from Advanced Fire Engineering (Maritime and Energy) and Ana Sauca from Advanced Fire Engineering (Buildings) are DBI’s primary drivers of the project.

The Centre for Rescue and Safety and Hovedstadens Beredskab must perform firefighting of battery fires and evaluate and formulate methods for them.

Stena Recycling supplies the end-of-life lithium-ion batteries to be used in the respective tests.

The National Research Centre for Work Environment contributes with its expertise in toxicology and the potential health consequences for firefighters from battery fires. In this connection, a collaboration with Lund University will provide expertise in the measurement and characterisation of particles.

Aarhus University provides insight into the chemical substances that are released from the batteries during testing and from broken batteries after the fire. The latter is particularly interesting in relation to the recycling process of used and damaged batteries.