Bob Hamilton is a reporter for The New London Day covering defense issues.
s an electrician’s mate striker on a diesel-electric submarine, retired EMCS (SS) James Christley recalls the dirty, dangerous job of checking the batteries every couple of days to see if they were charged properly or needed water, climbing through a tangle of pipes and getting his lungs full of sulfuric acid fumes.
“You could always tell an electrician coming from two blocks away in those days, because of the look of his dungarees, which had been eaten away by the acid fumes,” Christley recalled. “Only the junior guys had to do it. One of the perks of seniority was you didn’t have to go into the wells.”
There were two types of boats in those days, the early two-battery boats that had 252 cells and a closed-cell ventilation system that was difficult to maintain, and the post-World War II Guppy (Greater Underwater Propulsion) boats with a simpler ventilation system that took half as much time to maintain, but with four batteries and 504 cells it still took about 2,000 man-hours a year.
Modern nuclear submarines have only one battery, with 126 of the 1,000-pound cells, and because they run on the reactor most of the time the battery wells stay cleaner and the maintenance requirements are reduced. In addition, improvements in the chemistry of batteries have made them safer, such as the use of calcium in the lead-oxide positive plate to reduce gas generation and water use. But it’s still manpower intensive, taking up about 1,000 hours a year. And they still generate explosive hydrogen gas when they are charging or discharging, and have to be checked regularly to make sure they don’t run low on water.
“And you’re still crawling around on a thing that looks like an old car battery, and if you’re doing that at sea when the whole ship is rolling you ‘re going to get zapped once in a while,” Christley said. “That’s the life of an electrician.”
But starting next year battery maintenance, a chore that’s as old as submarines in the U.S. Navy, will become a thing of the past. The San Diego-based USS DOLPHIN, AGSS 555, has already been outfitted with a new generation of sealed battery cells known as Valve Regulated Lead Acid or VRLA batteries, and a Los Angeles-class will get the new system some time next year, said Rear Adm. William G. Timme, deputy commander for undersea technology at Naval Sea Systems Command in Washington, D.C.
VRLA technology has been available for more than 20 years, but until recently they didn’t have sufficient energy density to be considered for undersea use. Better materials and design have yielded a product that makes sense for an SSN, and by 2010, the new batteries should be in use in all 72 attack and ballistic missile submarines in the fleet. The development work and original batteries will be done by Exide GNB Industrial Battery Division, Fort Smith, Ark.
Timme said one of his chief concerns in recent years has been that the company that makes the batteries uses about 15 percent of an otherwise unused old factory building in Kankakee, III.
.. We’re the only people still using these large, open lead-acid batteries, so they’re getting more expensive,” Timme said. “The company could walk away from this business at any time. The door is shutting behind us, and we have to do something about it.”
David S. Brugger, plant manager for the Fort Smith operation, said the Illinois plant was constructed some time in the early 1950s, and is the only one Exide GNB has still producing the old lead-acid open-cell batteries. The Navy batteries only use a small fraction of the capacity of the building, he said, and the plant will be mothballed once the Navy production there comes to a halt.
The new batteries will be sealed systems, similar to what are used in cars today, which not only require less maintenance, but are far more durable than their open-cell counterparts.
“In a compressed design like we’re going to be using, it can take a tremendous shock and still hold together, which is a distinct advantage for use on a warship,” Brugger said. In addition, the VRLA battery won’t leak much even if the casing is broken, Brugger said. “They’re more like a sponge, because of the way it’s constructed,” Brugger said. “From a safety standpoint, that’s a big plus in a submarine.”
In addition, although there’s a pressure relief valve on the VRLA battery, it would only vent in the event of a catastrophic failure that would probably be detected before it happened, he said. That means no more explosive and harmful fumes in the battery wells.
“It will actually charge and discharge, and all the gases produced during the process are recombined into the chemistry,” Brugger said. “You notice the difference even in the plants where the batteries are built. You walk through a plant that is making flooded-cell batteries, and it’ll clear out your sinuses. You walk through a plant where they’ re charging VRLA batteries, and you’ II never even notice it. It’s a noticeable difference.”
Similar sealed-cell batteries are already in use in surface ships, as well as military aircraft and a variety of Army and Marine vehicles. The batteries also offer a longer power supply, and will take up less space than the flooded batteries that they will replace.
Submarine battery production will be moved to Fort Smith, Ark., in a plant that is decades newer than the Illinois facility. And there won’t be the huge development costs typically associated with a military product.
“You’re getting a technology that was developed commercially over the years, with a lot of improvements just in the last few years,” Brugger said. “The product the Navy wants is one that we use extensively in the telecommunications industry, so all we’re going to have to do is tweak it, just change the size and the internal geometry, and it will be ready to go.”
The Navy is also hopeful that even with a smaller submarine fleet, the move to the new type of batteries will allow for competition in procurement contracts. EnerSys, a battery company in Reading, Penn., has already said it will enter the business with its thin-plate pure lead VRLA batteries, which offer a high energy density.
Timme said competition not only allows the Navy to negotiate for a lower price, but it no longer faces a situation where, if its sole supplier goes out of business, it would have to scramble to find another vendor.