Even without taking the transition from internal combustion engines to battery electric vehicles (BEVs) into account, the electrical power requirements of today’s vehicles have become daunting. Every device within a vehicle — from the air conditioner and seat heaters to the lighting and infotainment systems — requires power, and the wires supplying that power must have a large enough diameter to support the current.
The high number of devices and their corresponding wires creates substantial challenges in packaging and routing. As OEMs focus on improving fuel economy and EV range, the weight and cost of all those wires is coming under increased scrutiny.
Current dictates wire diameters, in that thicker wires have less resistance and therefore are necessary to safely carry higher current. The converse is also true: A lower current can safely run over a thinner wire, so reducing the current enables the use of smaller wires, terminals and connectors.
So, increasing voltage is an important tool in the toolbox to address increasing content, packaging, weight and cost. Since the 1950s, the average amount of current flowing through 12V systems has increased more than 650 percent. It is clearly time for another architecture overhaul.
Many automotive OEMs have targeted 48V as the most logical step forward because it hits a sweet spot: Increasing voltage by a factor of four reduces current by a factor of four while staying well below the 60V limit of what is generally accepted as protection against shock hazard. By adopting 48V, designs can be protected for up to 60V in the case of an overvoltage.
In addition to enabling significantly smaller terminals and wiring, the higher voltage is more power-efficient, as any power losses due to resistance in the power delivery system can theoretically be reduced by a factor of 16.
But OEMs that move to 48V have to pay particular attention to several key design considerations to ensure the system’s safety and reliability. Find out more in this white paper.
