The future of the motoring industry is electric, and it’s coming up faster than we expect it to be. Love it or hate it, car manufacturers are allocating budgets of ever-increasing sizes in empowering their current and future fleet to move around solely with batteries for a fuel tank, and utilizes a plug-in charger instead of fuel. However, battery technology at its current state of development is still years away from us being able to depend on them entirely, which brings us to an in-between solution – hybridization.
It’s important to note that there’s no one method – whether it comes to serial or parallel hybrids, each of them has its benefits and downsides. Recently we were given the opportunity by Volvo Cars Malaysia describing their take on their version of their very own hybrid system featured on their 2015 XC90 T8, the first 7 seater Plug-in Hybrid Electric Vehicle (PHEV), presented by no other than the managing director of Volvo Cars Malaysia, Lennart Stegland.
Volvo is not a newcomer when it comes to electrification; research and development with an aim to run their vehicles solely based on electric charge had started since the 1970s. The purpose is clear enough – electric energy has a higher total efficiency than fossil fuels and does not emit pollution nor noise in local traffic environments. With different hybrid architectures available, Volvo employs a parallel hybrid in its second generation SPA version which links the engine and electric motor separately via the transmission, allowing either or both sources of energy to propel the vehicle.
The innovative hybrid solution used in the XC90 T8 allows the SUV to excel in various aspects without the constraints of a typical hybrid vehicle. Unlike most implementations, Volvo places a conventional combustion engine at the front combined with an electric motor which not only assists the engine but also works as a generator and a starter, which energy needed to start the engine can be directly powered by the 400V lithium-ion battery without the need for the common 12V wet-cell. The Crankshaft Integrated Starter Generator, or CISG can deliver up to 180 Nm of torque and 34 kilowatts of power and is water-cooled via the vehicle’s thermal management system.
As the XC90 T8 possesses an all-wheel-drive system, the propulsion to the rear wheels is unique. Instead of a driveshaft connecting to the transmission to the rear axles, a second electric motor is placed with the purpose of driving the vehicle purely from the batteries, power boosting the vehicle with its combustion engine and for energy regeneration. This electric motor, or the Electric Rear Axle Drive (ERAD) is also far more capable than the CISG in terms of output as it can produce up to 240 Nm or torque and 60 kilowatts of power, with a 10 gear ratio and a disconnect clutch for a seamless, imperceptible activation when driving.
A high voltage battery allows efficient use of the battery’s charge, which reduces parasitic losses to heat and wire resistance. The battery pack used in Volvo’s hybrid system comprises of 96 lithium-ion cells with a voltage output of 270 to 400 volts, with the capability of storing 65 kilowatts and delivering 9.3 kilowatts per hour. To ensure optimum lifespan of the battery cells, the batteries are also water cooled during operation. With the vehicle turned off, the batteries are kept at suitable temperatures via the electric A/C compressor which directs chilled air to the battery radiator. With the absence of a driveshaft, the battery pack is now placed in the transmission tunnel – cleverly utilizing its location which does not compromise on space, and is suitable in terms of safety.
Being a PHEV vehicle, the XC90 supports charging from multiple sources, whether coming from the vehicle itself or from an external charging station. Tapping into the grid, the wallbox charger is easily installed from ordinary household mains to deliver 16 amps over the standard 220V household voltage to fully charge the battery in 5 hours.There are also dedicated charging stations available for those in a hurry which can complete the charging in 4 minutes; however it is noted that rapid charging could be detrimental to the battery’s lifespan.
One may wonder on the number of redundancies, fallbacks and fail-safes in place in such a complex vehicle. During the talk, Stegland revealed the entire car already had more than 100 modules in place, controlling specific components in the vehicle and is compliant to ISO 26262, the generic functional safety standard for electrical and electronic systems. The battery has also undergone various safety tests in the event of a crash, fire or a defect to ensure a very high degree of safety and has an International Protection (or IP rating) of 67, allowing the battery to be fully submerged in water without intrusion for 30 minutes.
With electrification being the logical solution to reduce our dependency on fossil fuels whilst reducing pollution and CO2 emissions, it has become Volvo’s imperative to offer a hybrid or fully electric variant on their upcoming models. With four models already offered with upcoming models to follow, along with their third generation CMA hybrid to debut in the year 2018, Volvo has solid plans all set to sail – and we can expect to see more in due future.