A recent study revealed that short driving ranges and battery technology are two of the key factors stopping consumers purchasing electric vehicles. A lack of range due to energy storage capacity can cause considerable downtime for businesses operating a fleet of vehicles. This proves costly and must be addressed if commercial electric vehicles are to be adopted more widely. Two examples of the resistors' applicaiton in electric commercial vehicles are full battery and energy capture.
Full battery
When the battery is full, or in the event of an electrical fault, a backup system must be employed to discharge the excess energy, often in the form of a resistor.
This emergency braking scenario is particularly crucial with heavier vehicles, including coaches, military vehicles and trucks, which may struggle to discharge energy when coming to a sudden halt. For safety reasons, regenerative brakes are backed up with traditional friction brakes, which are used when sharp braking is employed in emergency situations.
Energy capture
An alternative is using a water-cooled resistor for heating as well as braking. When energy captured through regenerative braking is passed through the water-cooled resistor, the heat passed into the cooling water can be transferred to the cabin in much the same way as in internal combustion cars.
This increases energy efficiency as the heat lost through braking is retained and put to good use. To put this into perspective, the energy efficiency of a conventional car is around 20%, with 80% lost to heat through friction. Conversely, regenerative braking may be able to capture half of the 80% and put it back to work by heating the cabin.
In addition, as regenerative braking means mechanical friction brakes are only used in an emergency, sudden stop conditions, there is far less need for maintenance. Accessory components don’t require any additional maintenance, unlike the high cost of replacing brake pads and discs on a whole fleet.
As Dyson’s move into the electric vehicle sector proves, electric vehicles, including commercial vehicles, are becoming extremely accessible. Retaining energy by using water-cooled resistors is just one way of improving the energy efficiency, safety, range and battery health of these vehicles, in turn reducing their carbon footprint. Actually various types of resistors are used in automotives, such as shunt resistors, current sense resistors. AEC-200 certified resistors are the best choice for automotives. Microhm Electronics' MMS series, MPR series, NFC series are qualified for this field.
