Audi has become the first mainstream manufacturer to start selling a car with a 48 volt battery – the SQ7 SUV has the extra power.
Like most technology in vehicles, the car battery has evolved over the years with the first common battery being introduced in the 1920s. The first battery was to help get the car started as electric starter motors became more popular and replaced the crank handle. These first batteries were only 6 volts.
The power output was increased during the 1950s to 12 volt as more vehicles required extra power to deal with new options such as air conditioning and a desire to automate many manual functions. Citroen and Volkswagen kept the 6 volt battery alive in their 2CV and Beetle models for many years longer, so it is interesting that the group who held on to the 6 volt should be the first with a 48 volt!
Why 48? In the 1970s after the battery had finally become a sealed unit, there was an idea to take it to 42 volts. This didn’t lead to anything, however the same reasons for moving from 6 to 12 now apply in moving to 48 – the need to power more equipment and even the car itself. Some cars have electric motors fitted for seats, steering, windows, mirrors and other devices and every one of them clearly takes power from the battery.
The development of hybrid cars with a combination of petrol and electric motors means many manufacturers are looking at the next iteration of the battery – it has been relatively stable for over 60 years with typical ongoing development to improve reliability and servicing.
The interesting thing about the SQ7 is that it uses a 48 volt electric turbo to provide extra power. A classic turbocharger uses exhaust gases to spin it up, which means that it will spin faster with more exhaust gas – the Audi can spin up quickly and be more constant at lower speeds with the electric motor. The car also uses 48 volt active suspension with a claim that it can adjust quicker to changes in road conditions.
Ford is part of a consortium called ADEPT (Advanced Diesel-Electric Powertrain) along with Ricardo and a group of universities that have a test car (a Ford Focus) that uses a 48 volt circuit that runs ancillary equipment such as the water pump and starter motor. The boffins are also looking at using a KERS (kinetic energy recovery system) using the higher voltage circuit and they are also developing a booster that could be used to give an instant injection of torque to the wheels alongside the electric turbo.
This last idea is called torque-assist and one idea is to use this to keep the car at a constant speed – similar to a cruise control – without the need for the engine to burn fuel. Importantly, the manufacturers could then increase the power output from ever smaller engines.
One current issue that has to be addressed is that these types of vehicles still need a 12 volt system as well to run all the smaller ancillary equipment fitted. This means two batteries onboard that will add to the overall weight of the vehicle. The development race is on to redesign all of a vehicles systems to cope with the increased voltage.
Once that is done, only one battery (and presumably one wiring loom) is needed and the vehicle can start to be lightened with smaller engines, gearboxes etc such that the driver gets the benefit of more power in a lighter, more fuel efficient package. The major suppliers of automotive equipment to the manufacturers are on the case, so expect to see more developments and market launches over the next 10 years.
It is an exciting time in the industry, we are seeing the pace of technological development start to get faster with each change heralding a new possibility for personal transportation.
This article first appeared on Patreon.