If you’ve been paying any attention to the consumer durables and electronics markets recently, you’ll have noticed that cordless convenience has all but taken over the industry. It’s rare to find corded devices anymore unless they’re for specialist or professional applications. The reasons are obvious: consumers prefer cordless devices because of the flexibility and mobility that they offer.
But what is the tech behind this revolution, and how did it spring up on us so quickly?
That’s the topic of this post. We look at some of the reasons why cordless convenience is now standard and why it’s increasingly difficult to find corded devices for virtually any application, from headphones to garden equipment.
The lithium-ion battery revolution
Top of the list of changes that have led to the development of cordless gadgets is the lithium-ion battery revolution. This started in the mobile phone segment but quickly spread to other areas of the consumer electronics ecosystem. Lithium-ion batteries have a low weight and a high power density-to-volume ratio, meaning that they are able to replace conventional wall tethers. Initially, engineers put lithium-ion batteries in vacuums, which was one of the most obvious use cases, but now they’re used in everything from the electric blower in your garden shed to the headphones on your head.
What’s so fascinating is that this change crept up on a lot of people quickly. Lithium-ion technology reached a critical price point around five years ago, making it possible for manufacturers to cost-effectively incorporate it into their devices. Right now, the cost per lithium-ion cell continues to fall, and more applications are likely to find their way into the consumer economy.
What’s more, lithium-ion batteries are easy to recharge and can be shaped around product design requirements. Many power tools, for instance, have interchangeable battery packs that slot in and charge quickly, allowing for continuous use throughout the day.
Brushless motors
A lesser-known development that has allowed more cordless technology is the invention of the brushless motor. Standard DC motors in conventional power tools required the use of a component called a brush, which pressed against the spinning commutator to deliver electricity to the motor’s armature. Brushless designs eliminate this point of friction, allowing motors to spin without the need for a brush to be in physical contact with any component.
It works by placing permanent magnets on a spinning rotor, with the copper coils remaining stationary outside. Small electric circuit boards determine when to energise specific coils to magnetically push and pull the rotor. What’s interesting about this design is that it reduces friction and eliminates operating noise. Many motors can deliver 50% more runtime on a single battery charge compared to their brushed equivalents, compounding gains in battery technology chemistry.
Smart power management
Smart power management is standard now on most cordless devices. That’s because it is so easy to place a chip on many of these products that can regulate power flow throughout the device to ensure that it’s used optimally.
Many cordless tools were previously dumb mechanical devices. You pulled the trigger, and then the battery dumped energy into the motor unit until it died. With cordless tools containing tiny computers, many now have microprocessors that can communicate between the tool, the battery, and the charger to improve system performance.
For example, chips can regulate device temperature and constantly monitor heat output. If there’s an issue, they can send a warning message to the display for follow-up. Smart microchips can also prevent over-discharge, which is where lithium-ion cells can drain completely dry within a few minutes, damaging them in the process. There’s also overload protection, particularly for power tools that come into contact with physical materials and may face resistance.
Expanding ecosystem of platforms
Alongside this, there’s an expanding ecosystem of platforms for cordless tools and devices. Many manufacturers now design their products to be compatible with many different tools. For example, many batteries are now available as single-slide-in style 18 V or 20 V packs. There’s no longer any need for bespoke chargers, so manufacturers can add inexpensive mass-produced equipment to their products to lower prices for consumers. Many use standardisation down to the level of individual screws and construction methods. Sometimes it’s possible to use the same battery pack for a wireless lawnmower as it is for the vacuum used to vacuum out your car.
Rapid charging
Rapid charging is one of the most important technologies explaining the rise of cordless equipment. Historically, batteries took a long time to charge, with many owners having to charge overnight and be organised with their charging routines. With rapid charging, pumping electricity into a battery at a high speed is now possible.
Many of these chargers have built-in cooling elements that allow them to transfer large amounts of power to chemical energy quickly. Sometimes it’s possible to charge a massive 5 Ah battery from dead to 100% in 45 minutes. Many handheld devices also have passive cooling architectures. Bosch’s CoolPack technology is a good example of this. This external housing helps to wick heat from the device to keep it cool and safe.
Miniaturization via semiconductors
Miniaturisation via semiconductors is another technology that’s often overlooked by consumers, but it’s essential for cordless convenience. Motors and batteries get most of the glory, but tiny electrical components called MOSFETs are doing a lot of the heavy lifting.
These miniature components essentially act as gatekeepers for electrical currents. They fire thousands of times per second to convert DC current from batteries into the signal required by brushes to drive brushless motors. Improvements in semiconductor technology mean that electrical resistance levels inside MOSFETs are lower than they were before. This means that MOSFETs generate less heat than they did previously, allowing them to operate more efficiently and save battery power.
Ultimately, all of this means that the future of devices is unplugged, handheld, and portable. Cordless convenience is being taken to the next level because of the technologies discussed in this post. Whether you’re a weekend warrior or a professional contractor, virtually anybody can benefit from this revolution.
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