New Battery Technology
Published: September 2006
Cordless tools powered by lithium-ion batteries are attracting a growing number of enthusiastic users, including many electricians. Lithium-ion batteries are not new and in the past, have been used to power small hand tools. But the introduction of Milwaukee’s new 28-volt tool line was the first time the technology became available for drills, hammer/drills and saws. Since then, companies introducing lithium-ion powered tools include Bosch, Makita and DeWalt. Many of these products are perfectly suited for electrical and datacom work.
Bringing lithium-ion technology to professional-grade cordless tools been called the most significant power tool development since the introduction of the first cordless tools. The now available Lithium-ion chemistry has allowed manufacturers to produce cordless tools with industrial power ratings and increased run times without increasing tool weight.
“Lithium-ion batteries offer tradesmen many important features that ensure increased productivity on the job site,” said John Sara, Milwaukee senior product manager for cordless tools. “Not only are lithium-ion batteries smaller and lighter than traditional batteries, they also run up to two times longer than NiCd [nickel cadmium] counterparts. Lithium-ion batteries offer consistent fade-free power, ensuring that the last cut feels as strong as the first, better performance and better run-time in hot and cold environments. Some lithium-Ion batteries available have a built-in ‘fuel’ gauge, which eliminates the need to guess how much charge there is in the battery pack.”
Technology applied differently
While manufacturers generally promote the same basic benefits of lithium-ion powered tools, the ways they apply the technology to their products is not the same.
“The approach Milwaukee has taken features a lithium-ion manganese chemistry, which has been in use for over 10 years in military and other mobile applications,” said Sara. “Milwaukee and Molicell, a leading global battery company, further developed this chemistry and introduced the first heavy-duty lithium-ion battery for use in high-amp draw power tool applications.”
Edwin Bender, Bosch cordless group product manager, said while other companies have focused on larger tools, Bosch developed the smallest, most powerful in their class and comfortable to use lithium-ion tools—10.8-volt drill/drivers available in two models.
“While power and run time are important, the true long-term value of any cordless power tool is cycle life: the number of charges and discharges a battery will offer before needing replacement,” said Bender. “Lithium-ion batteries provide maximum performance during the entire battery charge without the gradual decrease in power typical with NiCd batteries.”
Bender said that although some are promising cycle-life numbers into the thousands, the true proof is only apparent 12, 24 or 36 months after tool purchase.
“However, buyers can look for specific battery features designed to extend the cycle life of a battery: higher voltage, heat reducing battery-pack design, and electronic cell protection,” he said. “These types of features will help extend the cycle life of a battery and protect electrical contractors’ investments.”
Christine Potter, senior project manger for DeWalt, said when evaluating the benefits of the technology for power tools, it is important to first be clear about what lithium-ion means.
“Whatever the battery type, 18-volt is still 18 volts; 12-volt is 12 volts; and so on,” she said. “Lithium-ion does not mean power, which is determined by voltage; run-time, which is determined by amp-hour rating; or torque or speed, determined by tool design. Lithium-ion batteries offer a better power-to-weight ratio compared to other battery technologies. Essentially, lithium-ion provides an ergonomic benefit.
“DeWalt created its 36-volt lithium-ion platform to perform equal to or better than many of the industry’s leading corded tools, while weighing a similar or less weight than their corded counterparts,” she continued. “This development allows users of corded tools to cut their cords and experience the freedom of a cordless tool that can perform high-draw applications on the job.”
Potter said DeWalt did not adapt existing tools to use lithium-ion batteries—rather they designed tools from the ground up with innovative features to increase productivity, ease of use and durability.
Steve Steadings, director of product development for TTI North America, said the introduction of lithium-ion tools sets a new benchmark in the quest for cordless tools with corded power.
“In a variety of trades, lithium-ion battery-powered tools will become new standards and will enhance user productivity significantly,” he said. “There are differences in battery chemistry and battery control systems. The chemistry that Ridgid uses safely provides for the high current uses that are typically seen in professional power tools. There are also vast differences in the electronics used to control the charging and discharging of the battery packs.
“The Ridgid system monitors and controls several characteristics of the individual cells to optimize the power and life of the pack. These electronics also have the ability to upload the ‘use history’ of every battery to a computer for analysis,” he continued. “This data will allow for future optimization of batteries and tools to be sure that the performance matches the user’s actual needs. There are also different feature executions and different performance goals. Ridgid focused on power and run time while others concentrated on size and weight.”
Some believe advances in lithium-ion technology opens the door for its application to larger tools and many other types of products.
Sara said that is already happening with the introduction of the cordless band saw, bringing a traditionally corded tool to the cordless realm.
“As the technology advances, the power tool industry will see more examples of this,” he said.
Bosch’s Bender said lithium-ion technology makes it possible to expand tool lines to cordless designs, which will change the way professionals accomplish their work.
Impact on the tool market
Have the new lithium-ion powered tools made cordless tools powered by other types of batteries obsolete? Manufacturers say no, at least not for the immediate future. Substantially higher costs of lithium-ion batteries alone are a factor, and those satisfied with the performance and battery life of NiCd- and nickel metal hydride (NiMH)-powered tools may see little reason to change.
Robert Chetelat, product manager at Hilti—a company that does not currently offer lithium-ion powered products—said Hilti sales have not been affected by availability of lithium-ion tools because the current line of tools offers greater performance.
“NiCd and NiMH batteries will remain the dominant part of the market for the near future,” Chetelat said.
Potter said there still is a huge market for NiCd and NiMH tools, which will remain relevant as long as they provide necessary power and run time for those who use them and that DeWalt will continue to support those platforms. Steadings said Ridgid continues to offer NiCd-powered tools and expects its lithium-ion products initially to have minor impact on NiCd sales.
“However, as the lithium-ion market becomes more competitive and the technology becomes more cost effective, prices will fall somewhat and more professionals will begin to migrate to lithium-ion,” Steadings said.
Bosch continues to offer NiCd-powered cordless tools and to make improvements in its NiCd batteries. In 2005, Bosch launched a new NiCd line with 50 percent longer cycle life, said Bender.
“Milwaukee still offers cordless NiCd tools in 12-volt, 14.4-volt and 18-volt platforms,” said Sara. “While the majority of Milwaukee end-users benefit from advancements in lithium-ion technology and require the most heavy duty and powerful tools on the market, there will always be a place for NiCd batteries due to their value.
“However, lithium-ion cordless tools are quickly becoming the preferred tool on the job site. Overall, lithium-ion technology is changing the expectation for how quickly certain jobs can be handled. They can also trust that their lithium-ion battery will not fade, but will maintain a high level of performance from the first cut to the last. As the technology continues to advance, contractors can further enjoy corded power in their cordless tools. They benefit from not having to struggle with multiple extension cords, especially when outlets are scarce and can justify the higher initial cost of the lithium-ion platform by time and money saved.” EC
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at 405.748.5256 or firstname.lastname@example.org.