Power Tool Batteries: A Technology Story

Lithium-ion batteries are the go-to power source for power tools, and wireless charging is making battery-operated power tools even more efficient.
Oct 20, 2015 7:15 AM ET

Battery power could be thought of as the most important yet least considered element of power tool operation. Great battery power, runtime and longevity are expected. But a lot of technology and brainpower goes into the ongoing march toward greater productivity. Here’s what the landscape looks like today.

The Advantages of Lithium-Ion Technology

Lithium-ion batteries make ultra-compact and heavy-duty tools the norm, not an exception. And the three inherent benefits—more power, runtime increase and no weight penalty—are the basic building blocks behind the technology.

Lithium-ion cells can either hold more power in the same-size package (as tools change) or maintain the same power in a smaller package. The reason can be found at the basic chemistry level: A single lithium-ion cell can hold and use up to 3.6 volts, but weighs less than its predecessor NiCad cell. As a result, a 36-volt lithium-ion battery offers twice the voltage capacity of previous technologies, even as it weighs about the same.

Any increase in voltage will increase runtime; consequently, users inherently benefit with a runtime increase along with the power advantages of increased voltage.

The Battery Life Challenge How a manufacturer preserves its battery products’ battery lives is important. Similar to any engine or machinery, extensive heat resulting from high amp-draw applications can cause damage to battery cells and drastically shorten their lives. Only by engineering the battery and its cells to resist these conditions are manufacturers able to bring a lithium-ion battery with acceptable life to the professional market and not cost end users significant investment and continual battery replacement.