Ultra-wideband Wireless Signals Simplify EV Batteries

A new ultra-wideband wireless system that collects data from batteries could help boost the range of electric vehicles and simplify their development and assembly.

Electric vehicles collect a lot of data from their batteries, such as information about their voltage and temperature, in order “to ensure the proper operation of the battery pack and prevent failure or safety hazards,” says Jesus Ruiz-Sevillano, director of product marketing for battery management systems at NXP Semiconductors in Munich.

To gather that data, EVs often employ complex wiring harnesses within battery packs. These harnesses take up space that could otherwise go toward storing more energy. In addition, Ruiz-Sevillano says, wiring together a dozen or so modules inside a battery pack during production requires a qualified labor force to manually plug connectors over and over.

Replacing these wiring harnesses with wireless systems could boost the amount of energy a battery pack can hold, and simplify assembly. “This results in increased throughput, and reduced risk and human error,” Ruiz-Sevillano says.

However, until now, wireless battery management technology was narrowband, operating in limited frequencies, such as the 2.4-gigahertz range used in Bluetooth Low Energy technologies. These systems face numerous challenges within electric vehicles.

For instance, the metal casings and interior architecture of battery packs introduce many reflective surfaces for wireless signals. This means these transmissions may reach a receiving antenna by multiple paths, resulting in distortion and fading. Interference may also come from other wireless systems in the vehicle operating in the same band as the wireless battery management system. To mitigate these problems, electric vehicle companies have to develop complex adaptive channel selection algorithms, Ruiz-Sevillano says.

Ultra-wideband Wireless for Car Battery Health

NXP has developed the first ultra-wideband wireless battery management system for electric vehicles. It encodes data in low-energy wireless pulses across a 500-megahertz range for short-range, high-bandwidth communication, Ruiz-Sevillano says.

The use of ultra-wideband pulses can help the new system identify and deal with reflected signals. The greater a signal’s bandwidth, the shorter its possible duration. In the case of NXP’s system, its pulses are about 2 nanoseconds long, which means it can very precisely measure when signals reach antennas. This helps it filter out reflected pulses—the pulses that took a longer path reflecting off surfaces arrive later. The ultra-wideband nature of the signals also help it avoid interference from other systems in an electric vehicle.

Compared with narrowband wireless battery management systems, Ruiz-Sevillano says NXP’s system can achieve four times higher throughput, reaching up to 7.8 megabits per second. That it also can avoid multipath interference means it can dramatically reduce software complexity and overall…