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Johnson Matthey Battery Systems has provided the battery for Jaguar Land Rover's XJ_e engineering research vehicle – an experimental plug-in hybrid version of its luxury Jaguar XJ saloon.

Case study: Jaguar PHEV

The parallel hybrid design powertrain allows the vehicle to run in all-electric, all-petrol and combined modes with a smart energy management system that automatically selects the most efficient mode for the vehicle.

The XJ_e has an electric range of up to 40km (25 miles) and has tailpipe CO2 emissions of 75g/km, a 70% improvement compared to the standard Jaguar XJ.   a maximum electric mode top speed of 75mph.  This equates to a fuel economy of 87 miles per gallon.

The XJ_e was engineered through a collaborative R&D programme (REEVolution), part-funded by the UK government's Technology Strategy Board to develop range-extended and plug-in hybrid electric vehicles.  Johnson Matthey Battery Systems' role was to develop and deliver a validated battery system.

One of our key challenges was to ensure that the battery fitted into minimal space in the existing XJ car boot; this required tailor-made casing and precision design.

Johnson Matthey Battery Systems also supported the development of a bespoke liquid cooling and heating system with enhanced control through the thermal microgen software for cold and hot use.

Battery characteristics

  • Lithium iron phosphate (LiFePO4) 20Ah pouch cells
  • Nominal Voltage: 307.2V
  • Peak Discharge Power: 88.6kW
  • Continuous Power: 33.7kW
  • Nominal capacity: 12.3kWh
  • Battery weight: 159kg

The successful conclusion of the XJ_e demonstrator project proves Johnson Matthey Battery Systems' ability to meet the needs of a complex and demanding OEM application, which crucially was delivered on time and on budget.


The Jaguar XJ_e experimental Plug-in Hybrid engineering research vehicle was awarded 'Most Energy Efficient Luxury Car Prototype' and 'Technical Panel's Award of Merit' in the RAC Future Car Challenge in November 2012.