With advancements in lithium-ion battery technology enhancing fire safety protocols, we are entering a new phase in lithium-ion battery fire safety
Lithium-ion batteries have become essential to modern society. From smartphones and power tools to e-bikes, drones, electric vehicles, aviation and largescale energy storage, increasingly powerful batteries are being integrated into almost every part of our lives. At the same time, the fire risks are changing.
A lithium-ion battery fire is fundamentally different from a conventional fire. Once a cell enters thermal runaway, internal chemical reactions generate heat and flammable gases. This can lead to fire, the release of hazardous gases and, critically, the propagation of thermal runaway from one cell or battery to the next.
For Anogas, this means that the development of fire suppression technology cannot stop at extinguishing visible flames. The challenge is increasingly about controlling the complete event: extinguishing flames, removing heat, limiting propagation, managing continuing gas release, preventing re-ignition and, in certain applications, safely containing a failing battery.
This is driving the next phase in the development of our Hydrogel technology.
High performance without PFAS
Environmental responsibility has been a fundamental requirement in the development of Hydrogel from the beginning.
Hydrogel is a water-based extinguishing agent containing more than 95% water and is based predominantly on nature-derived materials, including mineral clay. It contains no intentionally added PFAS and is designed to provide effective fire suppression without relying on persistent fluorinated chemicals.
This is becoming increasingly important as industries around the world move away from PFAS-containing firefighting products.
For Anogas, however, eliminating PFAS was never intended to mean accepting lower fire performance. The objective has always been to combine environmental responsibility with a fundamentally different approach to fire suppression.
Hydrogel achieves this through several complementary mechanisms.
Cooling that stays where it is needed
Water is one of the most effective and widely available cooling media. The challenge is keeping that water in contact with extremely hot surfaces long enough to remove the required amount of energy.
Hydrogel is designed to address precisely this problem.
Its high water content provides rapid heat absorption, while its rheological and temperature-responsive properties help the material remain on hot surfaces rather than simply running away.
Under application shear, Hydrogel can be discharged as a relatively low-viscosity liquid. Once deposited, it recovers viscosity and adheres to the surface. At elevated temperatures, this effect becomes even stronger.
The result is a persistent, water-rich cooling layer where the cooling capacity is required.
For lithium-ion batteries, this is particularly important. Extinguishing the flames is only the first step. Heat stored within cells and surrounding battery components can continue driving thermal runaway and can initiate failure in neighbouring cells.
Sustained cooling is therefore central to limiting propagation and reducing the risk of re-ignition.
Creating a physical barrier
Hydrogel also forms a physical barrier around the affected material.
The mineral platelets contained in Hydrogel create a tortuous pathway through the deposited layer. This structure can restrict the movement of oxygen towards the surface and the migration of flammable gases through the layer.
In a lithium-ion battery event, gas generation can continue after visible flames have disappeared. Understanding how the Hydrogel layer interacts with this continuing release is therefore an important part of our development work.
The combination of adhesion, cooling and barrier formation means that Hydrogel does more than attack the flame. It creates a protective layer around the affected material.
This barrier mechanism is becoming increasingly important in our research into larger battery systems and containment applications.
Immobilising reactive materials
The mineral component of Hydrogel provides another potential contribution beyond cooling.
The extremely high surface area of the clay particles allows certain substances released from damaged cells to interact with the mineral structure. Anogas is investigating how these interactions can contribute to immobilising reactive materials and stabilising the damaged battery environment.
This complements the physical effects of cooling and isolation.
The Hydrogel platform therefore brings together several mechanisms:
- Rapid heat removal.
- Sustained cooling through adhesion.
- Physical isolation of the affected area.
- Restriction of oxygen and flammable gas transport through the deposited layer.
- Interaction with, and potential immobilisation of, reactive battery materials.
It is this combination that forms the basis of Hydrogel technology.
Moving towards larger battery fires
Much of the early development of lithium-ion fire extinguishing agents focused on relatively small batteries and portable extinguishers.
That remains important, but the market is rapidly moving towards significantly larger energy capacities.
E-bikes, drones, industrial battery packs, electric vehicles and stationary energy storage introduce a different problem. The question is no longer simply whether an agent can extinguish one burning battery. It becomes:
How effectively can the technology prevent thermal runaway from propagating through a much larger battery system?
This has become an important focus of Anogas’ current research.
Our testing is increasingly aimed at understanding the relationship between battery capacity, battery configuration, accessibility, application method and the amount of Hydrogel required.
An important lesson from this work is that accessibility can be just as important as extinguishing-agent performance.
If Hydrogel can directly reach burning cells and adjacent batteries, its cooling and barrier mechanisms can be used efficiently. If the cells are enclosed deep inside a battery pack, effective heat removal depends on delivering the medium to the location where thermal runaway is occurring.
For larger batteries, the future of fire suppression therefore lies in combining an effective extinguishing medium with intelligent application technology.
This opens opportunities for Hydrogel in fixed systems, injection systems, penetrating devices, sprinkler-type installations and other methods designed to deliver the agent directly to the battery.
From extinguishing to propagation control
Our growing experience with larger battery configurations is also changing how we define successful fire suppression.
Flame knockdown alone is not sufficient.
The more relevant questions are whether the intervention can stop or reduce propagation, how quickly temperatures decrease, whether adjacent cells can be protected and whether re-ignition occurs after application has stopped.
This changes the role of the extinguishing agent.
Alongside extinguishing a fire, Hydrogel becomes a tool for thermal management and propagation control.
That is particularly important as battery energy capacities increase. Saving neighbouring cells or modules can make the difference between a limited battery incident and the loss of an entire battery system.
A new challenge: Lithium-ion batteries in aviation
Aviation presents another very specific lithium-ion battery challenge.
Passengers and crew now travel with smartphones, tablets, laptops, power banks and other rechargeable electronic devices. A thermal runaway event involving one of these devices creates a difficult situation because it occurs in a confined environment where passengers, crew and combustible materials are in close proximity.
Extinguishing the initial flames is only part of the problem.
The damaged device can remain extremely hot, continue releasing gases and potentially re-ignite. Continued cooling and appropriate containment therefore become important considerations.
This has led Anogas to investigate an approach that combines fire suppression with containment.
Introducing Hydrogel Shield
As part of this research, Anogas has developed a special Hydrogel formulation called Hydrogel Shield.
Hydrogel Shield is considerably thicker than our standard extinguishing Hydrogel. Instead of being optimised primarily for discharge through a conventional portable extinguisher, it has been developed to create a persistent, water-rich protective layer around a damaged or burning battery.
The objective is straightforward:
Extinguish, cool, isolate and contain.
The increased viscosity allows Hydrogel Shield to remain around the device and maintain close contact with its surfaces. Its high water content provides a thermal reservoir for continued cooling, while the mineral structure provides the barrier properties characteristic of Hydrogel.
This makes Hydrogel Shield particularly interesting for containment solutions in which a small lithium-ion device can be placed into a dedicated container after the initial fire has been controlled, where the equipment design and operating procedures permit.
Hydrogel Shield is being investigated as a medium that combines water’s cooling capacity with the additional advantages of adhesion, physical isolation and restricted gas transport through the material.
Containment as an additional safety layer
The development of Hydrogel Shield reflects a broader change in our thinking about battery fire safety.
For certain applications, a complete strategy may require several complementary interventions:
Detection → extinguishment → cooling → containment → continued cooling → safe removal
For aviation, this approach is particularly relevant because a damaged battery requires continued management within a confined cabin environment.
A containment solution using Hydrogel Shield could potentially provide a controlled environment in which the battery continues to cool while being isolated from surrounding combustible materials.
Containment also requires careful management of continuing gas generation, heat and pressure. The Hydrogel formulation and the container must therefore be evaluated together as a complete system.
Our current research is focused on understanding how such systems should be designed, how much Hydrogel Shield is required and how effectively the technology can manage heat and propagation during continuing thermal runaway.
Developing new application technologies with our partners
The next generation of Hydrogel development is not focused only on changing the extinguishing agent itself. Together with specialised partners, Anogas is developing new ways of storing, transporting and applying Hydrogel for significantly larger fire scenarios.
One development area is aimed specifically at fire brigade applications.
Transporting large quantities of ready-to-use Hydrogel is not always the most efficient solution for fire services, particularly when very large battery fires may require substantially more extinguishing medium than can be carried in conventional portable systems.
For this reason, Anogas and its partners are investigating concentrated or thickened Hydrogel formulations that can be transported in a compact form and diluted with locally available water at the scene of an incident.
The objective is to allow fire brigades to carry a manageable quantity of concentrated Hydrogel technology and convert it into a much larger quantity of ready-to-use extinguishing medium when required. This could be particularly relevant for EV incidents, large battery packs, industrial battery installations and other situations where sustained cooling is required.
A second development area is sprinkler and fixed suppression technology for industrial applications.
Because Hydrogel is fundamentally water-based, there is considerable potential to integrate the technology into systems that use water as the primary extinguishing medium. Together with partners, we are investigating how Hydrogel can be incorporated into sprinkler-type and other fixed suppression systems for applications such as battery storage, production facilities, warehouses and other industrial environments.
The aim is to improve how effectively the available water remains on hot surfaces and continues cooling the area where the thermal energy is concentrated. System development includes evaluating delivery, distribution and compatibility with the intended equipment.
Increasing effective volume through expansion
Another important research direction is the development of different expansion technologies.
We are investigating methods that increase the effective volume and coverage of Hydrogel during application.
The challenge is to achieve this expansion without sacrificing the cooling and extinguishing performance that makes Hydrogel effective.
Several technologies are being evaluated to determine how Hydrogel can be expanded while maintaining sufficient water availability, adhesion, thermal contact and barrier performance.
If successful, this approach could increase the area or battery volume that can be protected with a given quantity of stored Hydrogel.
For large-scale applications, this could become particularly important. Expansion increases coverage, but does not increase the amount of water available to absorb heat. The expanded material must therefore maintain effective contact with the battery and retain the characteristics required for battery fire control.
This means maintaining the balance between: Volume expansion + water availability + adhesion + cooling + barrier performance.
These development programmes illustrate an important principle behind the Hydrogel platform: the technology can be adapted to the specific requirements of the application.
Hydrogel SubZ: extending battery fire protection to −20°C
Another innovation within the Hydrogel platform is Hydrogel SubZ, a formulation developed for use at temperatures down to −20°C.
Battery fire protection is not limited to heated indoor environments. Outdoor installations, unheated storage areas and mobile firefighting equipment can face sub-zero temperatures. In these applications, the extinguishing agent must remain available when an incident occurs.
Hydrogel SubZ extends the platform into these colder operating conditions. Its formulation is designed to provide frost protection while retaining the combination of cooling, adhesion and barrier formation that underpins Hydrogel technology.
The development challenge goes beyond preventing freezing. The agent must also maintain suitable flow behaviour and work effectively with the intended valve, hose, nozzle and application system. Performance must therefore be evaluated for the complete extinguishing system under the relevant temperature conditions.
Potential applications include outdoor battery storage, charging infrastructure, industrial facilities and firefighting equipment exposed to winter conditions.
The development of Hydrogel SubZ also demonstrates why formulation flexibility matters. Different operating environments require different material properties, while the underlying objective remains consistent: delivering effective cooling and protection where they are needed.
Alongside Hydrogel Shield for containment, concentrated formulations for fire brigades and new expansion technologies, Hydrogel SubZ extends the range of applications that the platform is designed to address.
One technology platform, different formulations, different applications
Hydrogel does not have to be a single fixed formulation.
The balance between flow behaviour, adhesion, cooling capacity, frost protection and barrier performance can be adapted for different applications.
A portable extinguisher requires an agent that can flow rapidly through a valve, hose and nozzle and subsequently adhere to the affected material.
Equipment exposed to winter conditions requires a formulation designed to remain usable at sub-zero temperatures. Hydrogel SubZ addresses this requirement with a version developed for use down to −20°C.
A fire brigade may benefit from a concentrated Hydrogel that can be transported efficiently and mixed with water at the incident site.
An industrial battery installation may require Hydrogel to be delivered automatically through a fixed sprinkler or suppression system.
Large-scale applications may benefit from expansion technology that increases coverage while maintaining effective cooling and thermal contact.
A containment system requires the material to remain in position for an extended period and maintain close contact with the battery. Hydrogel Shield has been developed specifically for applications where containment and long-duration thermal protection are more important than conventional extinguisher discharge characteristics.
Together, these developments are transforming Hydrogel from a single extinguishing agent into a flexible fire suppression technology platform.
One Hydrogel platform, different formulations, different applications.
Please Note: This is a Commercial Profile
Please note that this article first appeared in our Lithium Battery Fire Focus book.
