In 2005, Milwaukee Electric Tool Corp. introduced the first lithium-ion powered cordless tools for professionals, and a good case can be made that the proliferation of lithium-ion tools that has followed is the most significant tool development in recent years.

To many tool users’ surprise, Milwaukee unveiled a line of 28V lithium-ion tools. They provide more power and weigh less than standard 18V tools. Their lithium-ion battery packs last twice as long per charge as nickel-cadmium (NiCd) batteries and sustain maximum power through each charge without the gradual decrease in power typical of NiCd batteries.

Makita soon unveiled a line of 18V lithium-ion tools, and other manufacturers entered the market with their own lithium-ion-powered products.

At the beginning of 2009, lithium-ion powered tools ranged from powerful 36V models to ultra-compact 10.8V products and accessories, such as compact work lights and wet-dry vacuums. Milwaukee’s compact 12V M-12 series and Makita’s 10.8V line were Showstoppers at the 2008 NECA Show in Chicago. The Milwaukee 12V line includes a digital inspection camera, copper tubing cutter and reciprocating saw. Also of note is the compact size of Bosch’s new 10.8 drill/driver and impact driver kits.

Paul Fry, group product manager at Milwaukee, compared lithium-ion technology’s impact to the way high-definition, flat-screen TVs and compact digital music players have changed consumer buying patterns.

“Lithium-ion has allowed for fundamental change in ergonomics, performance and durability of cordless tools,” Fry said. “The newest introductions in lithium-ion have come in the 10.8 to 12V tool range providing ‘tool belt’ portability and exciting new tools. Lithium-ion has also given the industry and its customers a green alternative to NiCd batteries.”

Edwin Bender, cordless group product manager for Bosch Power Tools and Accessories, believes the biggest impact of lithium-ion battery power for tools is that the technology gives manufacturers the ability to produce cordless power tools that are lighter, more compact and, ultimately, more powerful than previously possible.

“Less immediately obvious but nonetheless significant is that lithium-ion batteries also virtually eliminate problems, such as battery memory, which meant the premature demise of many a NiCd battery,” Bender said. “It should also be noted that lithium-ion batteries are far more environmentally responsible than NiCd.”

Brad Wheeler, Makita senior product manager for cordless products, said new lithium-ion battery technology has allowed premium brands of cordless tools to offer greater value than ever before because of runtime and performance.

“At the same time, the superior power-to-weight ratio of lithium-ion battery technology has allowed the introduction of new tools into the cordless category,” he said.

Manufacturers do not implement lithium-ion technology in the same way, and the lithium-ion batteries and battery packs of tools offered today are not necessarily the same as those that came with earlier lithium-ion tool models.

“The new battery technology presented a challenge to makers of cordless tools,” Wheeler said. “They could either retrofit older and existing tools to fit the new batteries, or they could complement the new lighter weight batteries with new tool designs that were lighter and stronger. Makita took the second option and engineered a new collection of cordless tools built around new lithium-ion batteries.”

Rapid developments in lithium cell technology continue, Milwaukee’s Fry said.

“A significant amount of research and development and investment is being made, not only in the power tool industry, but also by consumer electronics, automotive and defense companies,” he said. “All of this means that we have seen and should continue to see consistent improvements in all aspects of lithium cells.”

Bender said while core fundamentals of lithium-ion batteries remain fairly constant, power tool manufacturers have experimented with different chemistry formulations to find the best recipe for the power tool application.

“We have to remember that lithium-ion batteries were first developed for products such as cell phones, PDAs, laptop computers, cameras and digital music players,” he said. “Even in the most demanding situations, these products still exert a very low-intensity power draw from their batteries. Not so with power tools. Professional users expect their drills, impact drivers, saws and other tools to go straight from zero to redline and stay there for a while. This required tool manufacturers to come up with more robust batteries that could withstand job site conditions.”

Bender said it is important to understand that battery cells and battery packs are two different things. While the cells provide the power, the battery pack design is the responsibility of the tool manufacturer. He said Bosch developed features, such as electronic cell protection and electronic motor protection, in its tools to increase battery life, while also incorporating state-of-the-art, high conductive plastic material to move heat out from the core of the pack.

Tool users are benefiting from new cordless tools made possible by application of the new battery technology.

“For a terrific example of how the transition to lithium-ion battery power has influenced the design of tools, look at the far ends of the cordless tool spectrum: ultra-compact to heavy duty,” Bender said. “The proliferation of tools in what we refer to as the ‘ultra-compact category,’ typically 10.8 to 12V, has been phenomenal, and it is entirely because of lithium-ion power. Electrical contractors in particular are taking advantage of the benefits of these compact tools because they are very lightweight, they’re extremely maneuverable and they can get into very tight spaces, all without giving up anything in terms of power or durability. Before the advent of lithium-ion battery technology, tools like these weren’t even on the drawing board.”

At the heavy-duty end of the spectrum, Bender said lithium-ion technology enables manufacturers to produce cordless tools that match or surpass the power and capability of their corded counterparts without a major weight penalty.

“We’re now even able to produce cordless [reciprocal] saws and rotary hammers—tools for very demanding applications—using our 36V lithium-ion battery power,” he said. “The amazing strides made on both ends of the cordless tool continuum have ultimately also impacted the middle, the 14.4V and 18V tools that are staples of most toolboxes.”

The lithium-ion tool revolution is far from over.

“Lithium-ion will continue to allow our industry to provide new and exciting product solutions to the end-user,” Milwaukee’s Fry said. “The immediate future is greater levels of performance and durability in traditional cordless tools, as well as a number of new-to-the-world tools in all platforms. It is fair to say that you will see batteries in a number of places that you had never expected to see them.”

For Bender, lithium-ion is clearly becoming the new cordless tool standard in weight, power, run time and battery life.

“The transition to lithium-ion began with drill/drivers, impact drivers and hammer drill/drivers, not only because they were the most popular tools but also because they were the tools most hampered by the weight and performance limitations inherent in the NiCd battery platform,” he said. “Now that the transition is almost complete in the drilling and driving categories, we’re starting to see manufacturers produce some really creative lithium-ion executions in other tool categories. Many manufacturers, Bosch among them, have already introduced various types of handheld saws and cutting tools using lithium-ion. I only see this trend accelerating in the coming months and years.”

With the introduction of the first lithium-ion powered tools, higher cost was a factor. Considering the benefits of lithium-ion tools, that is less an issue now, and as more lithium-ion products become available, competition will drive down prices.

“We’re now seeing the cost differential shrink as more and more manufacturers get into the lithium-ion game,” Bender said. “So I expect that demand for NiCd and other previous systems is going to dwindle pretty quickly over the next few years, particularly as users discover they can finally buy a new lithium-ion tool for just a little more than the cost of replacement batteries for their old tools. And because of environmental factors, European nations have plans to all but eliminate NiCd batteries for power tools from the mix by 2010.”

An end to lithium-ion tool growth is nowhere in sight.

“Perhaps sometime soon we’ll see lithium-ion routers or even small bench top tools powered by lithium-ion,” Bender said. “The possibilities are really only limited by the imagination. If there’s a tool out there that is currently hampered in some way by its size, weight and power supply, I’m sure we’ll eventually see a lithium-ion model.”

GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at