Extinguishing battery risks in Australia’s energy transition

Thermal runaway poses significant challenges that must be addressed to ensure a safe transition to a sustainable energy system.

With the nation aiming to decarbonise by 2050, Australia is making significant strides towards a renewable energy future. As a result, utility-scale battery systems are poised to play a crucial role in stabilising the energy grid and managing the intermittent nature of renewable energy sources.

Batteries help balance energy demand and supply, charging when power is abundant and discharging when availability drops. They also help integrate energy sources such as solar and wind power into the grid. These functions are essential for optimising energy systems in the transition to a more sustainable energy future. But batteries are not without their drawbacks.

The perils around fires and lithium-ion batteries have been known for some time, but these risks are shifting as the technology matures. The central risk is thermal runaway, a process in which a lithium-ion battery generates flammable gases that can ignite, potentially leading to a fire or explosion.

Organisations that manage batteries can introduce several measures to prevent the initial triggers of thermal runaway. These include implementing well-designed cooling systems, early off-gas detection and monitoring systems to detect abnormal conditions. Additionally, addressing internal cell failures, overloads and overcharges is essential. Having a credible Battery Management System (BMS) that monitors batteries down to the smallest unit level is an expected prevention measure. These are key, because presently, there is no known widely accepted way to stop a lithium battery fire once it has started, often the only option is to let it burn out.

For outdoor utility-scale batteries with no other exposures, sprinklers are not part of the protection philosophy, although they may be in other situations. And while clean agents and aerosols can fight conventional electrical fires, a battery fire that enters thermal runaway is not a conventional electrical fire. This underscores the importance of understanding the unique risks around this important part of the shift to renewable energy and developing effective risk management strategies.

Media reports from Australia and around the world demonstrate some of the challenges involved with the proper handling of lithium-ion batteries. A notable incident happened during testing of the Victorian Big Battery site, when a 13-tonne lithium battery caught fire, which then spread to an adjacent battery bank.

This is just one example among many, and modern battery cell design may also be contributing to increasing risks. Previously, multiple cell failures within a battery container would have been necessary to produce enough gas to ignite a fire. However, as cell capacity continues to grow, the failure of a single cell can now generate sufficient flammable gas to create a hazardous atmosphere.

Although less of a restriction in Australia, limited land in other parts of the world means we are seeing increasingly higher density energy installations with less separation between units. This means fires can spread more easily between them, making it difficult for asset owners to limit losses.

How can these risks be minimised?

Proper management of lithium-ion batteries is a growing concern for organisations that operate battery assets, such as energy companies and solar farm operators who have co-located assets. It’s also a salient issue for enterprises that manage battery systems near shopping centres and for homeowners who have installed battery units. For any organisation managing lithium-ion risks, what’s essential, is to be proactive about risk management to limit potential losses, so insurers can provide the most accurately priced cover. The good news is, while stopping a lithium-ion battery fire once it’s started can be problematic, measures can be implemented to reduce the severity of the event.

An important aspect of proper risk mitigation associated with thermal runaway includes installing mechanical ventilation systems that can extract and expel the gases that batteries generate, to help reduce the build-up of flammable gasses inside the small remaining free space of a container. Deflagration panels are also required as a final mitigation measure to relieve the pressure from an explosion, before structural damage to the container occurs. There are other practical safeguarding measures, such as separating the batteries from each other by a safe distance.

The way battery systems are tested is changing, which is helping the sector develop a more comprehensive appreciation of the potential risks with associated them. We are already seeing updated safety standards such as NFPA 855 mandate more robust, large-scale fire testing, which will help to determine the worst-case fire scenario in a battery energy storage system (BESS) installation.

Managing evolving threats

These are just some examples of battery risk management techniques, and in the future, new technology will play a major mitigation role. For instance, we envisage that battery installations will increasingly incorporate immersion cooling systems, instead of traditional air or liquid cooling. Submerging battery cells in an insulating fluid can more effectively dissipate heat generated during thermal runaway, as opposed to conventional cooling systems that do not encase the entire battery module. Also, we expect more extensive use of AI to monitor and detect thermal runaway, allowing batteries to shut down more quickly or discharged to zero to prevent a fire from escalating.

Looking ahead, threats connected to lithium-ion batteries will evolve as the switch to renewable energy sources continues. To stay ahead of these challenges, businesses need to be prepared and draw on the guidance of brokers and other experts, ensuring they can effectively manage and mitigate emerging threats.