Wise-Integration, Savoy GaN Integration Sets New E-Bike Battery Charging Standard

July 04, 2023 by Jake Hertz

The companies claim to be the first in the world to integrate GaN charging into an e-bike battery.

In battery charging, the most significant design tradeoffs an engineer will encounter surround size, power, and efficiency. For devices to support quick charging, for example, they need to be able to output large amounts of power–but at a lower efficiency, greater power means more wasted energy and greater thermal generation. When devices pack more heat, they require more area for thermal management, compromising size. 


The companies teamed up to add a GaN charger to the e-bike’s battery

The companies teamed up to add a GaN charger to the e-bike’s battery. Image used courtesy of Wise-integration


In an ideal world, charging systems could simultaneously be small, efficient, and output large amounts of power. To this end, one technology with the potential to enable the best of all worlds is gallium-nitride (GaN). Wise-integration and Savoy Group claim to have created the world’s first e-bike battery with an embedded GaN charger.

This article will discuss GaN, its importance in power systems, and the Wise-integration news.


What is GaN?

GaN is a wide bandgap semiconductor material that has risen in prominence in the past decade. In general, the benefits of GaN stem from the impressive physical and electronic properties of the material.

One of the key benefits of GaN is that it exhibits extremely high electron mobility compared to silicon. From a power perspective, high electron mobility means that GaN FETs can achieve greater efficiency than silicon-based solutions thanks to low conduction losses (i.e., I^2/R losses). 


GaN transistors vs. silicon

GaN transistors vs. silicon. Image used courtesy of STMicroelectronics


Another benefit of high electron mobility is that GaN FETs can achieve much greater switching speeds than silicon FETs. By switching faster, GaN FETs can support higher-frequency operation than silicon FETs, leading to greater power efficiency thanks to the device spending less time in the transition region where most power is wasted.

Beyond efficiency, GaN’s wide bandgap of 3.4 eV means that GaN transistors exhibit extremely high breakdown voltages. Higher breakdown voltages translate into greater reliability and better performance at higher power than silicon can provide.


GaN for Power Systems

GaN technology's importance is particularly pronounced in the context of power systems. 

As electronic devices become more sophisticated, efficient and compact power systems become more critical. By offering higher-efficiency solutions than silicon, GaN-based power systems waste less energy and generate less heat than conventional solutions. Because of this, GaN helps create power electronics that can support higher power outputs without compromising sustainability.


GaN charger power density vs. silicon solutions

GaN charger power density vs. silicon solutions. Image used courtesy of GaN Systems


GaN's high-frequency operation also allows for the design of compact power systems, a critical factor in today's space-constrained electronic devices. Moreover, GaN's superior thermal performance ensures that power systems remain cool even under heavy loads, enhancing the reliability and lifespan of electronic devices while also decreasing their area requirements. This increase in power density leads to more affordable and performant charging solutions. 


Wise-integration and Savoy Group

Wise-integration, a player in the GaN technology space, successfully demonstrated the power of GaN technology at EUROBIKE 2023 in Frankfurt with the all-new Cocotte e-bike from KILOW, which is the industry’s first e-bike to integrate a GaN charger into the electric battery. By integrating the GaN charger into the battery, the company hopes to free urban riders from worrying about battery life and the additional weight associated with carrying portable battery packs. 

Thanks to the greater power density supported by GaN electronics, the Cocotte battery pack is lightweight yet powerful, providing users with a convenient and easy charging solution.