30 November 2012
Matt Galla had a serious case of engineer’s block. All he needed was the push of inspiration to be able to see a legacy design in a whole new light. Eventually, that inspiration came from an unlikely source — beer.
“We’ve had a business in TE Circuit Protection providing safe and reliable solutions when customers need resettable devices for a variety of applications,” said Galla, director of research, engineering and advanced development at TE Connectivity. “When lithium ion technology was brought to market in the early ’90s, the big issue was looking for ways to incorporate a safety device inside the cell to allow the batteries to be used more broadly.”
These safety devices are essential when considering the highly dangerous and volatile chemistry contained in lithium ion batteries. Battery manufacturers must take the right level of precautions in order to keep their consumers safe, and that means adding the right circuit protection device for the job.
Under its previous Raychem Circuit Protection brand 30 years ago, TE’s circuit protection group pioneered the carbon-filled PolySwitchTM PPTC (polymeric positive temperature coefficient), allowing the safety device to be resettable.
The applications for the device, however, were changing. Cell phone and personal computer technology evolved, and lithium ion batteries had to become smaller, lighter, more reliable and longer lasting, as did the components. The resistance of the carbon-filled device was simply too high for some applications. So, Galla’s team began to look at a materials approach and found that metals would have a lower resistance and improve performance.
“It’s a great idea,” Galla said, “but metals oxidize,” increasing resistance and ultimately leading to reduced system performance. This problem nagged Galla.
“Using nickel was a great solution, but the metal isn’t 100 percent stable. It wouldn’t last in a cell phone, and in a matter of a few months, you wouldn’t be able to use it,” Galla said. “We had a couple of projects going to solve the problem; we kept modifying formulations, but couldn’t quite get it to work. It was very frustrating. We kept coming up close, but never good enough.”
After years of redeveloping, redesigning and reimagining, they experienced the all-powerful “ah-ha!” moment. Galla was reading an article in an industry magazine about beer and baseball, of all things. According to the article, one materials company had a problem similar to the problem Galla and his team faced.
Beer vendors at baseball games wanted to replace glass beer bottles with a plastic alternative that would be lighter, easier to transport, and more convenient at games, “but plastic breathes oxygen. This company developed a coating to put on the bottles that was able to keep oxygen low for months, and I thought: We could do the same thing with our devices,” Galla said.
Galla and his team worked with the company and tried to implement their coating for a new circuit protection device — the Low Rho SMD (low-resistance surface mount device), but “we had issues in our applications that they didn’t have. We had to develop our own version,” Galla said.
Leveraging TE’s global reach, Galla, who is currently based in North Carolina, worked with a TE Circuit Protection team in Menlo Park, Calif., and Tsukuba, Japan, as well as another company in Japan that works to develop raw materials. In the process, he worked with teams across the U.S., China, and Europe.
“We read a lot about how this original company designed their materials, and we worked to develop something that worked really well with our applications,” Galla said.
The new Low Rho SMD was introduced to the market in September 2012, and Galla’s oxygen barrier patent won TE’s Patent of the Year award. The Low Rho SMD offers a device resistance 33% lower than the industry standard: 10 miliohms, compared to the 15-milliohm industry standard.
“We’ve had extremely happy customers,” he said.
Overall, Galla said the patented coating has also helped to open up process capabilities that TE has been able to use to its advantage, tailoring device performance to meet customer needs without having to start with a fresh device.
The elegance of Galla’s idea will be immediately apparent to engineers working within a “resistance budget” when designing battery-powered electronics, such as smart phones. Battery pack designers are pushed for lower packs resistance to enable both longer talk-time and simultaneous multiple device functionality.
With customers demanding longer battery life, designers must balance important tradeoffs when adding circuit protection devices to provide the lowest resistance possible. The Low Rho SMD offers designers the benefit of using a small, surface mountable device that also saves the precious milliohms that would otherwise exceed their overall resistance budget.
“We have a variety of versions now,” Galla said. The fundamental innovation, the oxygen barrier, launched in 2005, but Galla and his team had to continue to innovate and adapt that technology.
“We’ve had to completely reconsider how to design an oxygen barrier that would fit in all of these applications,” he said. “We’ve had to go back to the drawing board several times to fit applications.”
Different versions have to withstand extreme temperatures, humidity and other rough conditions.
Galla said that he is encouraged to innovate and allowed to fail at TE.
“Not only did we fail multiple times, but we failed famously and hard. These were some of the dark days of my career,” he said. “We had so many people working on an alternate technology route to get this low resistance in the traditional product, and it just wasn’t happening.”
Galla wanted to cancel the project and pursue something else. When his team turned to a metal-filled solution, it still didn’t work.
“Then we hit on the answer, that oxygen barrier. The company really did provide a very supportive environment to enable that solution,” Galla said.
With the right combination of inspiration, experience, talent and resources, Galla was able to take an existing process technology, apply new materials science, and develop the new oxygen barrier approach to give customers a more reliable, longer lasting product.
By Rebecca Jones, contributing writer