A chemistry agnostic low voltage switched-reluctance motor by Controlled Power Technologies (CPT) is being made widely available to the auto industry — and may even provide the answer for 12-48V lead battery mild hybrid solutions.
The system has the potential to pave the way for a new generation of affordable and cost-effective micro-mild hybrid cars.
The system, used inside a vehicle’s drivetrain, works by harvesting energy from regenerative braking to replace that which is lost from the battery during acceleration.
However, the system requires a battery which can maintain a 40 to 70% partial state-of-charge (HRPSoC).
The technology has already been showcased in an Advanced Lead-Acid Battery Consortium (ALABC) 48V LC Super Hybrid vehicle.
The demonstrator features Exide Orbital spiral-wound absorbent glass matt batteries featuring cathodes enhanced with carbon.
An alternative and equally effective lead-carbon design for 48V hybrid electrification is East Penn Manufacturing’s UltraBattery, which similarly offers a super-capacitive effect, said the spokesman.
The spokesman added advanced lead-carbon batteries were of interest to carmakers, because they an operate in sub-freezing temperatures as low as minus 30°C, and eliminate the need for an active cooling, and an expensive battery management system at a cell level.”
Allan Cooper, the European Project Coordinator at ALABC, said: “We are seeing 48V market as a potential battle ground between lithium-ion and lead-acid.
“The question mark is over the functions the car companies want to put on vehicles. The more they want to do, the more energy is needed and including a small lithium-ion batteries won’t do when you need more capacity.
“Lead-acid, from the point of view of car functions, is not a problem.”
Future uses for the technology only include low voltage automotive applications, such as truck, buses, cars and light commercial vehicles.
Question and Answer with CPT’s Robert Palmer
BBB) What type of chemistry are the batteries? If lead-acid will they be EFB or AGM batteries?
Palmer) We are agnostic regarding battery systems, and ultimately it’s for the carmakers to decide. The company is not a battery developer, but specialises in the development of cost-effective CO2 reduction measures for the global automotive industry through intelligent low voltage electrification of the powertrain. Its core competencies include low voltage power electronics, advanced control software and the application of low voltage switched-reluctance (SR) electrical machines to gasoline and diesel powertrains – providing 12-48V mild hybrid solutions. Its project partners for the 48V LC Super Hybrid technology demonstration programme include the Advanced Lead-Acid Battery Consortium (ALABC), AVL Schrick, Mubea, Provector, University of Sheffield and Valeo.
The 48V LC Super Hybrid demonstrator features Exide Orbital lead-carbon batteries to enhance performance, extend mileage and lower emissions at an affordable cost. The vehicle’s functionality includes the ability to harvest kinetic energy from regenerative braking using CPT’s engine mounted belt-integrated starter-generator known as SpeedStart, which also provides torque assist to the engine for acceleration. Performance and drivability is further enhanced by the Valeo electric supercharger – another switched-reluctance machine developed by CPT now licensed to Valeo, which following three years of industrialisation of the technology is now ready for high volume manufacture.
Under vehicle acceleration, the switched-reluctance machines demand of the battery system joules of energy, which are then returned to the battery as recovered energy when the vehicle is braking. Hence the need for a battery that can handle this high rate partial state of charge (HRPSoC), which is a critical requirement. The Exide Orbital spiral-wound absorbent glass matt batteries feature cathodes enhanced with carbon. An alternative and equally effective lead-carbon design for 48V hybrid electrification is East Penn Manufacturing’s UltraBattery, which similarly offers a super-capacitive effect.
Advanced lead-carbon batteries are of interest to carmakers, because of their ability to operate in sub-freezing temperatures as low as minus 30°C, which is an essential requirement for vehicles used in the snow belt areas of North America, Europe and various parts of Asia. They also eliminate the need for an active cooling, and an expensive battery management system at a cell level. Last but not least, they have a significant cost advantage over lithium-ion batteries, and a well-established high level of recyclability.
BBB) How long before the technology is brought to market and installed in new vehicles?
Palmer) The first vehicle to feature the Valeo electric supercharger is the Audi SQ7 as announced at the Frankfurt Motor Show. Other manufacturers will soon follow with their 48V mild hybrids. The SpeedStart motor-generator is also at a high level of technology and manufacturing readiness.
BBB) Has the technology got the capability to be used in non-vehicle applications?
Palmer) We are is focused on low voltage automotive applications, which includes trucks and buses as well as cars and light commercial vehicles.
BBB) Hybridise at what voltage
Palmer) CPT’s switched-reluctance machines operate in the safe 6V to 60V range.
BBB) Will the batteries rely solely on regenerative braking to recharge?
Palmer) No; the SpeedStart motor-generator performs the same function as the alternator it replaces to recharge the battery, but with additional functionality – such as its stop-start capability. The engine torque assist and brake energy recuperation functionality, however, demands that the battery be maintained at a 40 to 70% partial state-of-charge.