How About:Energy is helping McMurtry take on electric track records

Two years ago, the all-electric McMurtry Spéirling fan car shattered the Goodwood Festival of Speed’s hill climb record, clocking a time of 39.08 seconds. The hair-raising run shaved more than two seconds off the previous time, set by a Formula 1 McLaren in 1999. In the wake of its Goodwood success, McMurtry is now on the cusp of launching the Spéirling Pure, a track-ready version available to the public for a cool £1 million.

Needless to say, battery performance is fundamental to McMurtry’s endeavours. As well as powering the Pure’s 1000 bhp (745kW) peak output, its battery pack also serves the ‘Downforce-on-Demand’ fan system, enabling the vehicle’s incredible cornering speed. On top of this, the pack needs to be able to rapidly recharge so that a day out at the track doesn’t involve waiting around for hours in between each face-melting run.

So far, the various iterations of the Spéirling have been powered by the P45B, a high-performance lithium-ion cell manufactured by Taiwan’s Molicel. Production models of the Pure, however, are set to be equipped with Molicel’s follow up, the P50B, a 5.0Ah 21700 form factor cell, claimed to have one of the highest power densities in the world at 260Wh/kg.

When the P50B is released later in the year, the job of rapidly testing and modelling its unique performance metrics for McMurtry will fall to UK firm About:Energy. Founded in January 2022, the Camden-based startup combines expertise in battery testing and software to build digital models that can reduce reliance on physical research and engineering, speeding up design and development. About:Energy’s work on the P50B will allow McMurtry engineers to incorporate that data into the design and simulations of the Pure’s battery packs, ultimately getting the car into customers’ hands quicker, and in an optimised state.

“We started About:Energy to fill a fundamental research gap,” said Gavin White, the company’s co-founder and CEO. “A huge amount of research is going into developing battery models. But a very limited amount of research is going into developing the inputs for these models. About:Energy measures these inputs and provides them at a very high quality.

“Batteries are complex, which makes the testing and modelling we need to do equally complex. Batteries not only provide electrical current but also generate heat - properties driven by the chemical reactions inside. Over time, these reactions lead to battery degradation, impacting all other performance aspects. In our labs, we isolate these different attributes through precise measurement.”

White told The Engineer that About:Energy has been working with the Molicel P45B for the past year, testing large volumes of cells individually that correlates to ‘decades of battery test data’. This allowed About:Energy to build an enormous dataset for McMurtry, which in turn enabled the supercar manufacturer to simulate how the cells perform in tandem with the Spéirling. According to White, the experience they have with the P45B should allow the company to deliver a battery model on the P50B within about a month of receiving the new cells, allowing the McMurtry team to rapidly maximise battery performance on the Pure.

“McMurtry are one of Molicel’s flagship customers,” said White. “As soon as cells are available for testing, we’ll be fast acting to support the testing and analysis. 

“The release of the P50B is planned for later this summer. On the P45B, its predecessor, we have already completed extensive tests and are providing this to McMurtry to enable them to be able to push prototype performance with this cell further ahead of the P50B release and this technical partnership.

“Measuring the thermal performance of a battery takes weeks, while evaluating battery degradation can take years. As a company, we have developed unique methods and processes to obtain this data accurately, rapidly, and at scale. For the P50B, we will focus on reducing the average time to gather data and deliver value to our customers due to its relevance in industries that need to quickly advance technologically.”

In April of this year, McMurtry posted footage of test driver Max Chilton tearing around Silverstone in a Pure prototype, clocking F1 pace while tapping just 80 per cent of the car’s power and fan-boosted downforce. Inevitably, rumours of an assault on the Nürburgring Nordschleife are being whispered, with petrolheads eager to see if the Spéirling Pure can challenge the fastest times at the infamous circuit.

The ‘Ring – as it is affectionately known in motorsport circles - is an almost 21km-long track in Germany, often used by supercar manufacturers to showcase the performance chops of their latest creations. Some commenters have questioned whether the Pure’s battery can get it round the Nordschleife at full tilt, especially given the power demands of the fans, which deliver downforce by rotating at up to 23,000 rpm. If those doubts do have any substance, the P50B could help address them, as according to White, the new cells offer significant improvements over Molicel’s P45B.

“We have supported several Molicel customers in various industries using the P45B,” White told The Engineer. “Public data on the P50B shows that this battery offers approximately 10 per cent more energy and 30 per cent power (continuous discharge).”

One presumes these calculations have already been factored in by McMurtry, which says the Pure will ship with a 100 kWh battery pack. Given that the Volkswagen I.D.R – current holder of the EV record at the Nordschleife – was equipped with a 24.7 kWh pack, it seems the Pure should have more than enough juice to get round the ‘Ring, if McMurtry does decide to take on the challenge. And the models that About:Energy delivers may well help inform those decisions. According to White, the primary benefit that his company delivers to McMurtry and others is ‘time to insight’.

“This is the interval between receiving physical batteries from a supplier and understanding their performance at the vehicle level,” he said. “This facilitates the rapid design of battery packs or control systems for integration into vehicles. Battery design involves advancing technology and balancing trade-offs among various metrics such as cost, time, energy, and lifetime. For any given electric application, the battery is central to its performance.”

Once About:Energy receives new cells, it carries out physical testing at its lab in Camden, London. Cloud software is then used to process the test data, before About:Energy’s modelling team transforms it into models that replicate various battery performance behaviours.

“We package these models into fully functional digital models on platforms like Matlab Simulink, enabling McMurtry to integrate them seamlessly into their battery systems or vehicle concepts,” said White.

“These models are ‘white-box’, meaning our customers can see how the model works and the data that goes into it. This transparency is crucial for our most technically sophisticated customers like McMurtry, as it allows them to build more intellectual property and deepen their understanding in the battery domain.”

McMurtry will then use the models to optimise the performance of the Spéirling Pure and help it to answer several key questions: how to increase charging speed without impacting battery lifetime; how to enhance acceleration without compromising safety; how to increase battery regeneration to reduce vehicle wear; and how to improve in-use battery state-of-charge estimation.

“About:Energy does not provide McMurtry with the answers to these questions but provides the toolkit to find them,” White explained.

“The process will enable a team of world-leading engineers to spend less time testing batteries and more time developing world-class concepts and breaking records.”