+44 (0)330 223 5344


Lithium Battery Fire Retardant Box Design

Sandfield were approached by a manufacturer of high quality cars who, like most of the automotive industry, are investing heavily in electric vehicles, specifically lithium battery powered vehicles. 

Why did this vehicle manufacturer approach Sandfield Engineering with this Lithium Battery challenge?

Lithium Battery Fire Retardant Box Design requirement from an automotive manufacturer. 

This automotive manufacturer approached Sandfield Engineering because we have been providing them with Automotive Hand Clamps and Power Clamps since the mid-seventies. We have also been involved in producing a host of custom engineered solutions for them over the years. They are focussing right now, as most manufacturers should be, on their impact on the environment and we have also installed our water pollution containment devices on a number of their sites. 

So our relationship with this manufacture is proven and very longstanding. 

What was the particular Lithium Battery challenge that they were looking to overcome?

Anyone who knows anything about Lithium Batteries, which doesn’t seem to be very many people in this early stage of their use, will know that they have a propensity to catch fire if they overheat. Understandably, our customer had concerns that they were handling, storing and processing large numbers of these lithium batteries which represented a considerable risk. As these batteries pass along the production line there were concerns that they might start to overheat which could lead to them catching fire. What they needed was a quick and safe way of isolating and moving any battery tray that showed signs of overheating, or in the worst case had already caught fire, so that it could be safely removed from the production line and away from other batteries.

When they approached Sandfield they already had a proposed solution. However, that solution involved a manual process; closing the lid of the lithium battery fire retardant box by hand. This represented a risk as it involved the attendant staff knowing how to react, and actually reacting in exactly the way required in an emergency situation with an obvious risk to the personal safety of the staff member who had to complete the task.

It was clear that some kind of automated closing function was required.

What were the particular challenges?

There were five major challenges to contend with if we were going to design an appropriate solution.

The first challenge was finding a material that would effectively retard a lithium battery fire. Lithium burns at in excess of 550 degrees celsius. Whichever material we used would need to be able to withstand those temperatures without warping or distorting. This ruled out all non-ferrous metals and meant that the only viable option was to use Steel, Stainless Steel was ruled out as it was deemed to be too expensive. The next consideration was the thickness of the Steel, anything less than 3mm thick would not have effectively contained the fire and would have been likely to warp or distort at the anticipated temperatures.

This meant that the overall box, and the lid that needed to be opened and closed, would be extremely heavy. 

The second and biggest challenge was that the lid would need to be closed automatically. As we have established the lid would be extremely heavy, in fact it was in excess of 45kgs and this would have to close automatically without being powered. The entire box needed to be removed from the premises quickly with no time to disconnect it from any fixed attachments to the mains power or pneumatic air system. 

The third challenge was that the base of the battery tray was designed to conform to the shape of the vehicle and wasn’t flat. Removing the battery box from the production line in an automated way into our lithium battery fire retardant box wasn’t simply a case of just sliding it in.

The fourth challenge was how to suppress the fire. It was reasonable to assume that the fire would be contained in the box, but then you would be transporting  a fire through the production areas whilst removing the battery box from the factory. This would have involved a staff member putting on a fire proof suit, before removing the box using a forklift. It was felt that this would take too much time whilst posing a risk to the staff member who would need to be relied on to perform this operation in an emergency situation.

The fifth challenge was how to produce a cost effective solution that would be reusable. Each box would have to be made from Steel and would cost in excess of £5,000. So it was important that, to the greatest extent possible, the box should be reusable and made from materials wouldn’t be damaged beyond repair in the event of a fire.

What did Sandfield propose as a solution?

Sandfield proposed that the box should be made from mild-steel with a minimum thickness of 3mm. This would mean that the entire box would weigh more than 120kgs with the lid weighing in excess of 45kgs on it own. 

To overcome the lack of power issue we designed a series of linkages on a counterbalanced hinging system so that as the battery tray was inserted into the box it pushed against a bar that closed the lid in a controlled manner. The lid needed to close in a controlled way as if it were to slam shut there would be the risk of catching someone’s appendages or clothes, the mechanism that was pushing the battery tray into the lithium battery fire retardant box or in the worst case, projecting flames into the work area.

To safely move the battery tray into the box we custom designed a mechanism around the irregular battery tray base with strategically positioned roller tracks along the areas where the battery tray was flat. This allowed for the battery to be removed smoothly, quickly and precisely from the production line. 

The final challenge was how to extinguish the fire in the box. After some research we discovered that the most effective way to extinguish a lithium battery fire is to use fire retardant granules which are made of glass, we recommended Pyro Bubbles. Our design included  a mechanism that would automatically trigger the release of these lithium retardant granules as soon as the fire retardant box lid was closed. This involved lining the lid and the sides of the box with a mesh containing the Pyro Bubbles which would burn at low temperatures and release the granules onto the fire. We also recommended a hopper that would enable the addition of more Pyro Bubbles if they were required after the box was closed. 

We overcame the cost and reusability challenge through a design that incorporated mechanisms and materials that would not be destroyed in the fire. All of the components were made of Steel so that they wouldn’t melt or distort. Having a built in, automatic mechanism for extinguishing the fire quickly also meant that the box would not have to endure the effects of a fire for too long.

What is the outcome of this Lithium Battery Fire Retardant Box Design?

The outcome is a design for a Lithium Battery Fire Retardant Box that we feel meets the challenges outlined in the brief.  This would allow this vehicle manufacturer to operate in the comfort of knowing that if the worst were to happen and a battery were to catch fire on their production lines they have a process to ensure that any overheating, or in the worst case, enflamed batteries can be safely removed without risking the fire spreading or causing harm to staff members.

Speak to Sandfield Engineering about Fire Retardant Lithium Battery Box removal systems.

If your production process involves Lithium Batteries and you are concerned about how you might safely remove them in the event of an emergency we now have some experience in addressing this issue.

Do not hesitate to call us on 0330 223 5344 or email sales@sandfieldengineering.com to speak to us about how we can be helping you to implement safety facilities around Lithium Battery production processes. 


Dawn Tebbett

Dawn Tebbett

Managing Director

Dawn is a Qualified Engineer and Managing Director of Sandfield Engineering with more than twenty years experience in the design, manufacture and distribution of Toggle Clamps, Automation Products and Custom Engineered Solutions.




Get In Touch



What is a Stainless Steel Toggle Clamp?

What is a Stainless Steel Toggle Clamp? It's a question that often comes up so as leading UK Stainless Steel Toggle Clamp suppliers we thought we would have a crack at answering it for you. You may remember from our What is a Toggle Clamp post...

Designed & made by engineers for engineers. Sandfield, the toggle, power and bespoke clamp experts.



Sandfield Engineering manufactures an extensive range of Robot Grippers to compliment our range of Power Clamps including Power Clamp Grippers, Parallel Grippers and Angular Grippers. Check out our range of Robot Grippers here.


Vibratory Bowl Feeders are the most effective way of ensuring the efficient, fast and accurate delivery of parts in your manufacturing process. Sandfield  supply new feeding systems as well as servicing, relining and retooling your existing bowls.


Linear Rail or Linear Guide systems ensure the precise movement and loading of equipment or parts vertically or horizontally. Our team is hugely experienced in specifying Linear Rail solutions to ensure delivery of exactly the Linear Rail that you need.


Check out the range of Toggle Presses available in a selection of styles, pressures,  throat depths and ram shapes to suit your specific toggle pressing requirements.



Our close working relationships with hundreds of Manufacturing Engineers & Managers and the problem-solving nature of our clamps and holding solutions means that we are often called upon when other challenges arise in production processes.


Sandfield Engineering has always taken a consultative approach to the provision of clamps and a large proportion of the clamps that make up our range have been custom-designed in partnership with our customers to meet a unique clamping or holding challenge. 


No matter how impossible or unique your current component or part sourcing challenge might appear, with more than sixty years experience it is highly likely that our team have encountered something similar and can quickly steer you towards a solution.



What sets our water pollution prevention offering apart from our commpetitors is our willingness and capability to get to the route of your water pollution challenges and provide affordable, non-disruptive, compliant, fail-safe solutions.


Spill mapping

The Spill Mapping service provide by Sandfield Engineering empowers our customers to evidence their water pollution  risk and mitigate that risk precisely. This approach typically saves our customers as much as 50% when compared to more traditional proposals.

Containment Devices

Sandfield Engineering are the proud innovators and producers of the most effective water pollution containment devices. Our smart valves are independently powered, can be triggered automatically and provide you with all of the reporting you need to be compliant.



What is a Linear Rail?

What is a Linear Rail?

What is a Linear Rail? If you manufacture, pack and distribute things, if you need to move things through your manufacturing process with great precision and as little friction as possible the very best way to do that is using Linear Rails....

read more