Cool Tools: Lithium-Ion Technology
Published: April 2011
The introduction of lithium-ion battery-powered hand tools for professionals and their rapid proliferation among electricians and other trades arguably is the most significant advance in power tools since the introduction of cordless models.
Lithium-ion tools typically pack more power in smaller sizes, and lithium-ion battery packs can last twice as long per charge as nickel-cadmium (NiCad) batteries. They also sustain maximum power through each charge without the gradual decrease in power typical of NiCad batteries.
When Milwaukee Electric Tool Corp. unveiled its 28-volt (V) lithium-ion tool line in 2005, it caught many in the market by surprise. Makita followed with a selection of 18V lithium-ion tools. Today, Milwaukee, Makita, Bosch, DeWalt, Hitachi, and most major tool brands compete for the growing lithium-ion cordless tool market.
Indeed, lithium-ion technology truly has transformed the cordless tool market and made it possible to add cordless abilities to several categories of tools that previously were only available in corded models. Lithium-ion tools today range from compact “pocket” models to powerful 36V tools, and the price gap between lithium-ion and NiCad tools has significantly narrowed.
“Lithium-ion battery technology has caused a fundamental shift in cordless tool technology,” said Paul Fry, Milwaukee director of cordless product management.
“It is a massive change in form, features and function,” he said. “Lithium-ion provides the opportunity for power tool manufacturers to create innovative new solutions and set new standards of performance and durability for cordless tools for electricians.”
Edwin Bender, Bosch Group product manager, said lithium-ion has had a tremendous effect on portable electric power tools.
“Not only has it made tools lighter than before, but it has also opened the door to new platforms at both the high-power and low-power ends of the spectrum—12V and 36V provide more versatility than ever before, and 18V now has the added versatility of being able to customize weight or runtime through the use of different battery packs,” Bender said.
Jason McNeil, DeWalt product manager, pointed out that lithium-ion batteries have long been used for a variety of small, handheld electronic devices that require much less power than professional hand tools.
“Cell suppliers have worked to optimize lithium-ion technology to meet the power and runtime needs of power tool users,” he said. “Over the last several years, lithium-ion batteries have proved to be a new potential power source for handheld cordless power tools.”
What are the benefits of lithium-ion?
Milwaukee’s (www.milwaukeetool.com) Paul Fry said: “One benefit is runtime. Our latest lithium packs can provide as much as twice the work of a comparable NiCad pack, all while providing full power from the first cut to the last. Because of its high power density, one lithium cell can do the work of as many as three NiCad cells. This means smaller, lighter and more environmentally friendly batteries. Lithium also retains its charge longer when not in use and has no memory effect.
“Another important benefit is expanding tool lines: 12V lithium-ion is the fastest growing segment in professional power tools. Electricians have taken notice of the performance of these compact products, and we are seeing them in more job boxes and in the tool pouches of more electricians across the country every day. Not only does the performance meet the needs of their applications, but there are more and more tools being introduced to complement their compact 12V drills that are designed specifically for electricians with more on the way. When an electrician can use dozens of tools powered off of the same compact 12V battery, they have a system of compact tools that fit in their one tool bag instead of occupying much-coveted space in their truck or job box.”
Bosch’s (www.boschbestbuilt.com) Edwin Bender said: “Versatility and weight savings are the biggest advantages. With lithium-ion, you can get about three times the voltage out of a cell compared to a NiCad cell of the same size. There have been compact tools before, but they were never quite powerful enough to see consistent use. Now, our 12V max line provides tremendous power in tools that are only about 2 pounds and less than 6 inches in length. Our 36V line provides power similar to corded tools and runtime that was unheard of 10 years ago. Our 18V system is now able to deliver more power than our previous NiCad tools but with a weight savings that makes them even more comfortable. Finally, a unique property of lithium-ion cells compared to NiCad is that you can combine the battery cells in different ways to increase or decrease the runtime versus the weight. This battery customization within one voltage class changes the game for users who previously had to move to a lower voltage and power level to get a weight savings.”
DeWalt’s (www.dewalt.com) Jason McNeil said: “There are three main benefits to lithium-ion tools compared with NiCad batteries versus nickel-based batteries:
• “Power-to-weight ratio: Given the chemical makeup of lithium-ion batteries, cell suppliers can achieve a greater power-to-weight ratio than nickel-based batteries. Typically an 18V lithium-ion battery will weigh as much as a 12V nickel-based battery.
• “Smaller battery size: Lithium-ion batteries require fewer cells than nickel batteries to achieve the same voltage, making lithium-ion battery packs smaller than nickel-based battery packs for a given voltage.
• “Limited self discharge: lithium-ion battery cells in general don’t lose their charge nearly as fast as nickel-based batteries. If a professional power tool user forgets to charge their lithium-ion battery over a weekend, the battery will still have the charge it was left with on Monday morning.”
All lithium-ion batteries are not the same. How is your brand different?
Milwaukee, Paul Fry: “Not all lithium-ion is created equal. Milwaukee is on its fifth generation in as many years. Our new RedLithium battery technology will provide up to 40 percent more runtime, 20 percent more power and 50 percent more recharges than standard lithium products. The new technology will also operate in extreme temperatures as low as 0°F and will run 20 percent cooler with fade-free power and no memory effect. Our company also offers industry-leading electronic features that optimize the performance of every tool and protects the user’s investment in abusive situations.”
Bosch, Edwin Bender: “In addition to incorporating features such as electronic cell protection (ECP) in the Bosch system to protect against abuse, the special heat-conductive housing and fluted design helps to transfer heat out of the pack as quickly as possible. Heat is the ultimate enemy of any battery, so this design leads to longer battery life in the Bosch offering.”
DeWalt, Jason McNeil: “Battery pack chemistry plays a part in how a power tool performs, but the tool itself—switch, motor, transmission—is an important part in performance, as well. DeWalt strives to optimize the entire system to ensure the best performance. This is achieved by working with end-users to understand expectations and funneling those expectations back to the world’s largest battery suppliers to ensure the cells being developed are able to exceed the end-users’ expectations. All of the lithium-ion cells for DeWalt tools are optimized for use with DeWalt power tools.
What changes do you expect to see in hand tools powered by lithium-ion?
Milwaukee, Paul Fry: “Lithium-ion will continue to drive the development of innovative products that redefine end-user productivity and will continue to raise industry standards for cordless performance and reliability. For example, Milwaukee has leveraged the advancement in lithium-ion to expand the market’s vision for cordless by introducing a 12V PVC shear, test and measurement products and heated jacket.”
Bosch, Edwin Bender: “Batteries are only one part of the tool. New motor and gearbox technologies and electronic designs are in process right now, and they will complement both the current and future lithium-ion-driven tools. Users will see longer runtimes, smaller, lighter tools and more power as a result of all these developments. Users can get a first glimpse at the future when they look at our second-generation 12V max drill drivers. By combining all the best technology out there, we were able to make these tools up to 20 percent shorter while increasing the power.”
DeWalt, Jason McNeil: “User demands for handheld power tools with lithium-ion batteries continue to be communicated to battery-cell suppliers, who recognize the handheld power tool market as a tremendous opportunity for their businesses. Cells are currently being worked on to better satisfy these demands, and I anticipate this activity to continue. Lithium-ion battery cell suppliers see the handheld power tool market as a tremendous opportunity for their business. As the technology evolves, I would expect lithium-ion batteries to continue to find their way into more and more handheld power tools.”
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at email@example.com.