Cordless Tool


We've seen big changes in battery technology over the last few years, especially in the Li-Ion sphere. More and more power tools - and larger ones - are being run by ever-more-powerful packs. But new advances of late have been more or less limited to just that: bigger rather than surprising. So, WoodEzine decided to take a look at what might be coming to a workshop near you over the next few years...

Based on research done for more than a decades at Stanford, manufacturers are now looking at using silicon nanowires (extremely thin wires) to increase the surface area of the electrodes on portable power tool batteries. These electrodes (anode - and cathode +) are currently made of graphite, and scientists would much prefer to use silicon. The new wires promise to improve performance, because they won't wear down as quickly as current forms of silicon. In a Scientific American blog last year, the magazine reported that "Stanford battery startup Amprius has developed a new large-scale manufacturing technique for advanced silicon electrodes that could actually enable mass production of high-energy lithium-ion batteries in the near future, and help bring the next generation of electric vehicles and consumer electronics to fruition." Bottom line: they can store more energy. Silicon is a better power bank than carbon, but in its traditional form it expands and contracts so much that your batteries have a short shelf life. Nanowire batteries won't have that problem.

A company called Ionic Materials, which is based in Woburn, Massachusetts, has come up with what is essentially a battery that doesn't have a liquid element. That liquid has been a problem (it's what causes some batteries to start on fire). According to the company, "when a conventional lithium-ion battery is punctured, the battery shorts and the temperature increases rapidly, causing the liquid electrolyte to decompose and the cell to expand and burst. As the reaction continues, the liquid electrolyte ignites and expels flames and toxic gas from the battery. These thermal events have occurred in recent widely publicized incidents involving smartphones, toys, electric vehicles, and aircraft." What Ionic Materials has developed is a solid polymer electrolyte material that conducts ions at room temperature. Soon, the company says, we will see significant improvements in battery safety, performance and cost.

Late last year the journal Nature Energy published a paper by several Japanese scientists that promises "High-power, all-solid-state batteries using sulfide superionic conductors." Solid state means there is no liquid in them. The group, which has some attachment to the battery research division at Toyota Motor Corporation, says that it has developed "lithium superionic conductors with an exceptionally high conductivity , as well as high stability (compared to existing Li_ion batteries). A fabricated all-solid-state cell based on this lithium conductor is found to have very small internal resistance, especially at 100C (212F, the boiling point of water). The cell possesses high specific power that is superior to that of conventional cells with liquid electrolytes. Stable cycling with a high current density of 18 C (charging/discharging in just three minutes; where C is the C-rate) is also demonstrated." So, it's safer, faster and less resistant.

Science Daily has a page dedicated to the latest news about batteries and energy storage. The site recently reported that scientists at the University of Bath in the U.K. are working on a way "to develop batteries that store more energy is to use 'multivalent' metals instead of lithium. In lithium-ion batteries, charging and discharging transfers lithium ions inside the battery. For every lithium ion transferred, one electron is also transferred, producing electric current. In multivalent batteries, lithium would be replaced by a different metal that transfers more than one electron per ion. For batteries of equal size, this would give multivalent batteries better energy storage capacity and performance." So far, they have discovered that titanium dioxide can be modified to allow it to be used as an electrode in multivalent batteries.

The world looks to Elon Musk's Tesla for innovations in this field, because the car company is the largest buyer of Li-Ion batteries on the planet. This year Mr. Musk confirmed that the company is actively working on longer-lasting batteries, but hinted that he may soon reveal a big breakthrough in power storage. Musk is working with Jeff Dahn, a highly respected battery expert who leads a research group at the Department of Physics and Atmospheric Sciences at Dalhousie University in Halifax, Nova Scotia.

The sad truth is that, while numerous corporations and universities are working furiously to develop a new kind of battery, woodworkers are years away from any major benefits. For now, we have to be happy with battery packs that can power anything up to a small tablesaw, and hope that soon we will have smaller, more powerful options that make our portable tools more, well, portable. But progress is being made, as is noted by Consumer Reports in its cordless drill tests this month (September 2017).

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