A remote Cotswold farm address that has been operating since 2021 for research into EV battery fires have been conducting "dangerous" tests with no planning paperwork, documents reveal.

Quedgeley-based Advance Innergy Solutions Ltd (trading as AIS), which recently won the King's Award for Enterprise and is a world leader in insulation and passive fire protection, has told Stroud District Council that it began work three years ago into fire-testing Lithium-ion electric car batteries at a research unit at Burden Court Farm.

The address sits on the outskirts of the small village of Tresham, three miles from Wotton-under-Edge and close to the A46.

With five people currently employed at the site, the technology firm has informed planners it now uses the address as its main battery fire testing location - and wants to expand operations and the workforce there to 20.

For its "remoteness and isolation," Tresham is ideal for the work, the company said, which can be "dangerous".

Mr Tom Hatherall, the owner of the farm buildings where AIS is working, has now been directed to submit a retrospective application for all non-agricultural activity at the near-one acre site, including for a separate van conversion business which trades next door as J Customz Conversions.

Mr Hatherall, of The Furlongs to Burden Court Farm, told planners that he is seeking provision for vehicle storage and repairs, industrial processes connected to battery testing and "a material change of use of the agricultural land that extends around the perimeter of the buildings to create a hard surface for the siting of steel containers and the parking of vehicles".

In a statement on its website, AIS said: "AIS offers a complete Lithium-ion (Li-ion) battery testing service. This includes destructive and non-destructive testing of cells, modules, and high-voltage packs, to replicate the challenging and potentially destructive conditions that Li-ion batteries are subjected to during their lifecycle. In addition, our expertise in passive fire protection enables us to advise on the best solution to protect your battery system."

As explanation to planners, AIS said that its focus until recently had been on the oil and gas sector, but that when oil prices crashed in 2014 the business looked to enter new markets and diversify .

AIS added: "One market that AIS identified as a good fit for the company's products was the Electric Vehicle (EV) automotive market. EV's, powered with Lithium-ion batteries, can suffer from 'thermal runaway': aggressive battery fires with temperatures exceeding 1,000°C. This is a natural fit for AIS's material catalogue and expertise in passive fire protection."

AIS said its tests are performed by penetrating Lithium-ion cells with a nail which initiates a "thermal runaway event". 

"Small-scale tests of a few cells can be undertaken within AIS's furnace, as it is inherently fireproof, however larger scale tests, on multiple larger format cells, requires a dedicated test facility to account for the greater energy being produced during thermal runaway."

The company said it perceived "a gap in the market" for new materials and products to combat EV fire risks: "To this end AIS identified Burden Court Farm as a perfect site to invest in a dedicated battery test facility and exploit this opportunity... Burden Court Farm is an ideal site as it is close in proximity to AIS's head office in Quedgeley. Though of most importance is the site's isolation and remoteness. Testing of Lithium-ion batteries can be dangerous. Consequently, it is undertaken by trained and experienced staff in accordance with risk assessments, method statements and UK legislation."

The company added that the address was ideal for the nature of the business: "Isolation is key as it minimises any potential impact (traffic, noise, emissions etc) on local residents and businesses, and also reduces the potential risk to the public as there is little to no footfall in the area and allows AIS to deliver the testing in a safe, controlled manner without the concern that unsolicited members of the public may be entering the premises during a test."

Battery tests by  AIS form part of the regulatory requirements for a vehicle to be launched in the UK: "The safety testing, also performed at other test sites around the UK, will lead to thermal runaway events which are aggressive, hot fires. The risks to the operatives, the neighbouring businesses and residents, and the environment from these tests is being mitigated through the location (isolation) of the site, design of the facility, experience and expertise of the staff, and the working practices implemented by AIS.

Advancing fire prevention technology was essential, AIS said, so that fires "don't occur in a production vehicle on the road which would risk the lives of the vehicle's occupiers".

Hillesley and Tresham Parish council has been given until April 14 for its views. 

Simon Lee, chairman of the council, told Punchline-Gloucester.com that he was unaware of AIS's work at the site and that the parish would consider the retrospective application at its next meeting on April 9.

● A 2017 government research paper by the planning inspectorate on Li-on battery fires said: "Flouride gas emissions can pose a serious toxic threat," and added, "Lithium-ion batery fires generate intense heat and considerable amounts of gas and smoke. Although the emisson of toxic gases can be a larger threat than the heat, the knowledge of such emissions is limited."