A collaboration has been formed between Castrol and Sprint Power for the development of ultra-fast charging cells and battery packs for battery-electric vehicles (BEVs) and fuel cell hybrid electric vehicles (FCHEVs).
The collaboration is a direct result of Project CELERITAS, a £9.7m (US$11.1m) project with £4.8m (US$5.5m) funded through Advanced Propulsion Centre (APC) round 18, which aims to address the consumer concerns of EV charging speed.
Sprint Power has designed two battery modules – one for BEVs and one for hybrid applications – which will use Castrol’s ON EV Thermal Fluids to deliver an 80% charge in 12 minutes. Unlike traditional EV battery modules which use water-glycol coolants housed within channels, the battery modules developed as part of the pair’s project use Castrol’s ON EV Thermal Fluid.
The dielectric fluid circulates within the modules and comes into direct contact with the individual battery cells, increasing the thermal management surface area. This results in faster charging and improves thermal management in a range of conditions to extend battery life. This way of cooling also reduces the risk of thermal runaway and thermal propagation.
Both solutions integrate all system electronics and incorporate multiple charging protocols to reduce weight and space. An integrated 800V to 14V DC-DC converter, an 800V battery management system (BMS) and direct cooling capabilities – where the cells are immersed in a non-conductive cooling solution – also feature. Sprint Power’s master BMS features a safety microcontroller for cybersecurity support, fault diagnostic capability and the ability to support CHAdeMO or CCS charging standards. The system can supply a voltage of 8-16V and can operate in temperatures ranging from -40°C to 85°C. Furthermore, a modular cell block design ensures the modules can be adapted for a range of different applications.
Sprint Power’s hybrid battery module has been developed for potential application to FCEVs and targets a power-to-weight ratio of 3kW/kg, excluding the DC/DC converter. The module can deliver 5kWh of usable energy, with a peak charge/discharge rate of 230kW (105kW continuous). For sportscar applications, the solution can provide 76kWh of usable energy, with a peak charge/discharge rate of 800kW (700kW continuous).
An integrated unidirectional 800V to 14V DC-DC converter handles a maximum power output of 3.5kW within a compact, power-dense package of 0.8kW/liter. The DC-DC converter is highly efficient, with a peak efficiency rating of 97%.