The development and commercialization of the valve regulated lead acid battery has been one of Ken Peters’ great contributions to the industry.
VRLA: the next step
For the past 30 years Ken Peters has been at the very heart of the development of the VRLA battery, effectively passing the baton on from John Devitt in terms of its commercialization.
But Ken Peters’ story starts in 1953 when he joined Chloride Electrical Storage Company at its Clifton Junction plant in Manchester.
In those days the global battery industry was dominated by three companies. The Electric Storage Battery Company (ESB) with more than 70% of the North American market, Accumulatoren-Fabrik AG (AFA) — now known as Varta — with factories throughout Europe, and Chloride, with plants in the UK and in all of its old Imperial empire countries.
These companies were almost self-sufficient in materials and components. The Clifton Junction factory employed more than 3,000 workers to produce two million car batteries a year, tubular motive power cells, Planté and flat plate stationary cells, submarine, aircraft and signals defence batteries with smelters, alloy, oxide and separator production lines and on the same site, expanders and additive preparation facilities.
As a trainee, Peters worked in all the manufacturing areas. There was little automatic equipment and he was involved in installing and operating the plant’s first automatic Winkel pasting machines. He joined the research department, which later moved to a new technical centre away from the demands of the manufacturing plant and was equipped with the most advanced analytical and test facilities.
The technical director was Montefiore Barak, a Rhodes scholar from New Zealand. His impact on Peters’ attitudes to the industry was huge — Barak was outward looking and instrumental in starting the International Power Source Symposium (IPSS); Peters was there at the inaugural meeting in October 1958.
“It was unique within the industry at that time,” he recalls. “Companies did not share even limited technical and test data, and it was the principal industry conference for many years.
“Until about 1960 all the major battery companies were more or less self contained in terms of their technology, so they did their own development of virtually everything and up to then, any innovations, either design or additives, separators, alloys, containers and the like were developed in-house and closely guarded. R&D consisted of electrical engineers, material scientists as well as electrochemists and designers.
“But after 1960, separate and independent companies were set up to supply materials and knowhow. Nowadays if a battery maker requires a special expander, separator or whatever, they contact the suppliers.”
Peters was immediately involved in a range of programmes including the manufacture of electrodeposited plates for torpedo batteries for the UK Admiralty and the development of impregnated cellulose separators.
“One early and successful job we did,” says Peters, “was to assess and qualify leady oxides produced in a new Chloride designed oxide mill fitted with in-built classifiers and temperature controls, the forerunner of many later installed at numerous factories. I learned a lot about the rheology of battery pastes during that work.”
“Maintenance free car batteries were topical and we studied gassing rates and impurity influences and developed and patented low antimonial alloys producing ductile thin grids which could be cast on automatic machines. This was before the widespread use of calcium alloys, a technology adopted initially from ESB which had developed these alloys for telecom batteries.”
Chloride sponsored basic research at several UK universities and as industrial supervisor, Peters visited and contributed to numerous publications in academic journals.
In 1960, Chloride, ESB and AFA (Varta) signed a technical exchange agreement. All three companies employed experienced and well-known electrochemists and researchers. Paul Ruetschi, Alvin Salkind and David Boden worked for ESB while alongside Hans Bode, a professor and also research director at AFA, was Ernst Voss, Dietrich Berndt and Eberhard Meissner.
“We had regular meetings at the three research centres. But in 1968 this arrangement was deemed to be unlawful and cooperation stopped,” says Peters.
Positive electrodes were the princepal interest of researchers in the 1960s with studies on the polymorphs of lead dioxide, on how to increase cycle life and corrosion resistance, how to improve the efficiency of the active material and of course to develop and make low maintenance or maintenance free batteries. In the latter case the objective was not so much to limit water additions but to market a ‘fit and forget’ battery which was highly desirable to both car makers and the private customer.
Adapting Ni/Cd to lead
In 1964 Peters started work on a programme which subsequently had a major influence on battery design. At that time, sealed rechargeable Ni/Cd cells that were leak proof and lost no water in service due to recombination of oxygen at the negative plate inhibiting hydrogen evolution, were popular for portable equipment. Earlier gas recombination devices used expensive and inefficient catalytic systems.
“The same recombination approach seemed possible with lead and we started work to study its feasibility,” says Peters. “At that time I was also particularly interested in charge acceptance, not just of the cell or battery as a whole, but the individual charge acceptance of the plates. I measured this by monitoring the cathodic hydrogen and anodic oxygen evolution at different rates and temperatures and at different states of charge. Of specific interest was the high charge factor of the negative plate with 100% charging efficiency, that is no hydrogen evolution, until the plates were almost fully charged over a wide range of charging rates and temperatures.
“High charging rates with good recombination efficiencies were possible with separator saturation being the main controlling parameter. Subsequently we made several hundred D sized cells with wound lead electrodes and Porvic separators, the most porous separator available at that time. There were cost benefits over alkaline cells but the output was relatively poor and with no great enthusiasm for this work within the company, it was shelved.”
Although the project was no longer live, at this point fate intervened with a series of meetings that were to help change the face of the battery industry forever.
“I later presented a performance comparison of three types of D cell (primary Leclanché, alkaline and lead acid) at the IPSS conference in 1971,” says Peters. “At the same meeting I was approached by Don McClelland of Gates Rubber Company. I didn’t know Don nor the company, whose principal business was tyres and hoses. Gates apparently had similar ideas some years earlier and had formed a venture group specifically to develop batteries for cordless equipment, nickel/zinc and lead acid being the obvious candidates.
“McClelland sent me 50 wound, D size lead acid cells which we tested and I reported to my management that they were rather special.”
The reason for this was that the highly porous resilient and compressible glass separators maintained close contact with the plate surfaces and resulted in cells which had high power capability, cycled well and, says Gates, could be charged, seemingly, forever without water loss.
“I suggested a similar design approach could be used in Chloride’s main industrial and automotive batteries with very beneficial effects. Subsequently I was invited to visit Gates at their Denver head office for discussions with their management board.”
Under John Devitt, Gates had put together an experienced team: both Devitt and McClelland had worked on nickel/zinc and silver/zinc cells; Will Bundy, who had spent many years with the National Lead Company; and a young electrochemist named Kathryn Bullock, later to become president of The Electrochemical Society.
“I was invited to the Gates board meeting to validate, and possibly explain, the claims of their scientists,” says Peters. “Their interest in batteries was based on advice given to them by ADL, that small rechargeable wound cells for cordless equipment could conveniently be marketed on garage forecourts alongside their tyres and hoses. Subsequently a joint working group was set up to review the situation.”
Over the following months the group had several further meetings. The Gates team was keen to stick to their wound cell design but their manufacturing process was slow and expensive with very high scrap levels. High purity, and expensive, lead, litharge and red lead were used with high density pastes and formation over several days. The separators were high quality glass filter papers bought from the UK and although they were exploring cheaper US supplies, nothing had been qualified.
“It was difficult to see how Gates’ approach could be used to manufacture the larger batteries needed for industrial and automotive applications in the numbers required and at acceptable cost,” says Peters. “We agreed to follow different approaches. Gates would pursue its wound cell approach for the cordless appliance market while Chloride would consider how its existing manufacturing plant, such as the casting and pasting machines, could be used to make products with the same beneficial features as the Gates cell.”
Range of batteries
Peters went on to develop a range of telecom and UPS standby batteries using more or less conventional methods. Plates wrapped in compressed glass microfibre separator were inserted in strong plastic containers fitted with one-way valves. New processes and equipment for acid filling and formation were developed and a source of good quality glass microfibre paper was found.
“Our new valve regulated cells had appreciably higher volumetric energy density than the existing batteries,” says Peters. “Power outputs were better and with no water losses or gases evolved they could be located on power racks in offices or where most convenient to the end user. Our first prototype designs were supplied to British Telecom for trials in the late 1970s and production began at the Clifton Junction factory in 1983.”
The success of the new batteries was astonishing.
By 1989 BT had installed 500,000 2v/100Ah valve regulated cells in power racks in its system X digital telephone exchanges, and was installing them at a rate of 120,000 per year.
Within a few years distributed power supplies with similar valve regulated designs were adopted by telecom companies everywhere.
“Parallel with the standby battery programme we were developing valve regulated car batteries with similar beneficial features; leak and spill proof, improved cycling and a much higher cranking performance than equivalent flooded batteries,” says Peters.
“I think the major impact of my time in batteries was in converting and applying the Gates invention to the commercial battery field.”