Army makes Norwich students
part of battery safety test project © May 15, 2009, Norwich University Office of Communications
Lithium-sulfur dioxide batteries have long life, high durability and voltage and can function in a wide range of temperatures, making them ideal for use in Army communications, night vision devices, emergency-signal buoys and many other applications. But they can be dangerous.
Under certain conditions—low-temperature, high-frequency vibration, overheating or improper charging—violent chemical reactions occur in some batteries.
“The cases they’re in can become shrapnel,” said Donald Wallace, a mechanical engineering professor at Norwich University who helped bring three fledgling engineers into a military project to ensure the safety of soldiers using devices powered by these batteries.
Most of the time, we found a valve that was very good in two areas, and very weak in the other.
~ Michael Zalewski,
mechanical engineering student
For their senior project, Michael Zalewski, Brendan Lindquist and Scott Sylvester were tasked with improving a device to simulate the tremendous, often violent, venting of gases that occurs within the casing of a malfunctioning battery. This was no abstract exercise. Funded by the U.S. Army’s Communications-Electronics Research, Development and Engineering Center [CERDEC], their device may become part of the military’s official testing procedure.
“This is the one apparatus the Army will use to test these battery casings,” said Lindquist, of Canton, Mass. “It’s a pretty neat experience for a college student.”
Zalewski’s relationship with CERDEC goes back further than the academic year it took to deliver a prototype. He has been working at Fort Monmouth in internship programs for the Department of Defense since he was a high school student from Freehold, N.J. Zalewski approached Wallace with the idea of improving the testing mechanism, allowing it to simulate violent venting at a much higher pressure threshold. Wallace then visited the testing facility at Fort Monmouth and helped secure the funding—several thousand dollars for materials, machining services and travel expenses.
“This is a project I had worked on the summer prior,” said Zalewski, who has been offered a job at CERDEC when he graduates. “I had a strong familiarity with it.”
The Army had been testing casings at a pressure of up to 200 pounds per square inch [psi]. The students’ job was to design a system that would force nitrogen gas into a casing at 2,000 psi with a response time of 45 milliseconds.
“It’s a high-pressure, high-speed valve system,” said Zalewski, explaining that the design had to meet three criteria simultaneously to be successful: the correct response time, the right pressure and the proper volume of gas flow through the system.
“Most of the time, we found a valve that was very good in two areas, and very weak in the other,” he said.
In addition, the mechanism needs to be adjustable for testing different materials and sizes of battery casings, explained Sylvester.
“Every battery is different and made for different applications,” he said. “They need to be able to vary the pressure.”
After studying a number of valve types, the three students settled on a pneumatic ball valve, and set about construction of the device in Norwich’s machine shop. Students tested the components and subsystems, then assembled the device and tested it at about 90 psi. On spring break in March 2009, they traveled to New Jersey to try out their valve system in a safer environment.
After a day spent tinkering to gear the device to a different computer system and setup, they successfully tested the project at about 1,700 psi. Zalewski said he was confident it would work, but their time at Fort Monmouth was a bit nerve wracking due to time constraints and the need to have a semester-and-a-half’s worth of work come together in one moment.
“We did put more or less all our eggs in one basket with the use of the ball valve,” he said.
Wallace said he and other instructors work hard to find projects that push engineering students into the working world. Ideally, a company will find a way, as this one did, to help students acquire real-world experience that may apply to their eventual careers.
Sylvester, who will commission into the Army Corps of Engineers upon graduation, added he got a lot out of seeing how the military works at Fort Monmouth. “It was fun to work hand-in-hand with them, and hopefully get a foot in the door,” he said.
The students are waiting to learn if their valve system has been approved. Zalewski said the more important lesson was to learn about the process of developing a working device, but he’s confident the system will do what the Army needs it to do.
“The testing apparatus will be useful for evaluating and benchmarking that equipment,” he said.