The world is becoming highly dependent on batteries. More and more wireless – or better said cordless – battery-enabled devices become available. The recent uptrend for cordless machine tools like drills, vacuum cleaners, garden equipment and many more, show that batteries are now making it possible to deliver a higher discharge then ever before with acceptable weight and size specifications.
Where are the limits? Can it be done for every device? What are the possibilities for high-current battery-powered handheld devices like hair dryers or power tools. It seems so evident, however, a wireless hair dryer of 1600 Watt isn’t on the market yet, so can it become cordless?
Complexity of developing cordless battery-powered devices
After some research, we found a Chinese 1.250 Watt hair dryer. When looking closely, the battery is only for controlling the fan. If you want to heat the air, you need to plug it in. We also discovered a 300 Watt cordless hair dryer, however it showed to have a short battery autonomy and lifetime. 300 Watt isn’t that much.
A recently truly cordless 500 Watt hair dryer showed to be too bulky and heavy to become a commercial success. Let’s consider what needs to be done to generate a best in class 500 Watt cordless device?
Why? Well, there are many advantages to cordless hair dryers for users, mainly of course the added freedom during the use. However, developing a 500 Watt cordless device is complex and there are some disadvantages that need to be solved. To give some examples, there are less heaters that can work on low voltage, thicker cables are needed, the center of gravity needs to be optimized due to the perceived added weight of the batteries.
Key aspects to consider when developing batteries for these kind devices are obviously:
- Swappable vs rechargeable options
- Energy density (capacity inside)
- Power density, highest discharge rate
- Shelf life (retain capacity)
- Operational life
- Temperature range
- Battery life cycle
All of this will determine the type of battery. The figure below illustrates different options of the type of batteries in function of energy density versus volume. On the chart you can see that Li-ion batteries have the highest density, which is exactly what we need. Also, shelf life is better than most others.