The conception, invention and development of the VRLA battery has been an almost exclusively male preserve but one woman has made a remarkable contribution to its evolution — and also to the theoretical and practical landscape of the modern energy storage industry. Batteries historian, Kevin Desmond spoke to Kathryn Bullock.
Understanding is all-important
Perhaps it’s the association with lead. And possibly with cars too. But the batteries business until only recently has been entirely dominated by men. But one of the few women to burst through the glass ceiling of career advancement — and becoming a much-respected battery hero in her own right — achieved this by intellectual excellence, academic rigour and a deep understanding of the importance of linking research from the theoretical to the practical.
Kathryn and Judith Rice, identical twins, were born in Bartlesville, Oklahoma in September 1945. The twins were born into a scientific family.
The twins’ paternal grandfather was an engineer who led the development of the first Phillips refineries — Bartlesville was the headquarters of Phillips Petroleum and Cities Service oil companies — and developed the natural gas business. Their father, a geophysicist, had studied music and mathematics in college and did his graduate work at Ohio State University.
By profession their maternal grandfather was a mechanical engineer and inventor who owned a small company that made liquid level gauges for railroad tank cars. Kathryn and Judith were always welcome to explore his machine shop whenever they visited his company.
As the Rice twins grew up, their elders shared their many interests with them. Kathryn was interested in studying the stars, collecting rocks.
When Kathryn was 10 years old, her father took a job at a new Marathon Oil Company research laboratory near Denver, Colorado. She learned shorthand and typing so that she could work there in the summers during college, filling in for secretaries on vacation.
This gave her an opportunity to learn about research in different areas, including geology, chemistry and other physical sciences.
“My father and his colleagues encouraged me to pursue a scientific career, and I decided to focus on chemistry. Girls were not given chemistry sets in those days, but I had ample opportunity to experiment with food chemistry in the kitchen.”
At Colorado University, Kathryn was the only female in a laboratory of 50 male students. “My lab partner told me that I was in the wrong field for a girl, and the lab instructor was not encouraging either, even though I got good grades,” she says. “I finished a Bachelor of Arts degree at Colorado University with honours in English literature and writing and minors in French and Chemistry.”
The Devitt connection
In 1967, Kathryn married Ken Bullock. She also started looking for a job. “Fortunately I applied to Gates Rubber Company and was interviewed by John Devitt, who was organizing a battery development group. He decided to hire me to do a combination of secretarial and technical work, since his new department was too small to need a full-time secretary,” she says.
“I enjoyed working on nickel oxide-zinc batteries so much that I decided to go to North-western University near Chicago to get a masters in Chemistry while my husband studied at an Anglican seminary there. Although I had been accepted to the graduate school in the English department, they told me that they had a policy of not giving fellowships to married women.
“I had no money to fund graduate work, but the chemistry department offered me a laboratory job and outlined the courses that I would need to take to enter the graduate chemistry programme.”
Kathryn worked full time for nine months doing computer programming for professor Donald Smith and took enough maths and chemistry courses to enter the graduate programme the following autumn. Smith provided her with a stipend for teaching and doing electro-analytical research and in 1972, Kathryn Bullock earned a PhD in physical chemistry and electrochemistry.
In her graduate research, she used alternating current polarography to study the kinetics of organometallic reactions and experimentally verify the electrochemical models of homogeneous chemical processes coupled with electrochemical reactions.
Her twin sister Judith was to follow another path, majoring and then lecturing in English literature, specialising in the Renaissance writers at the University of Saskatchewan in Canada.
After five years in the Chicago area, Ken and Kathryn Bullock returned to Colorado and she re-joined Gates.
By that time, John Devitt and his team had developed the VRLA battery, and Don McClelland was leading the work to test and refine the design and develop the manufacturing processes. The first application of the Gates VRLA AGM battery was in power tools. Lead-acid batteries with silica gel added to the acid could be used in some portable applications, but the gel limited the power.
Portable power tool companies were very interested in the VRLA cells because of lower materials costs and higher voltages and power. Although lead is heavier than nickel and cadmium, they could use three lead-acid cells to replace the voltage of a battery of four nickel-cadmium cells.
When lead-acid batteries are discharged, the state of charge decreases as the acid concentration decreases. Many stationary lead-acid battery applications, such as standby backup power, required regular monitoring of the acid specific gravity with a hydrometer to determine the energy left in the battery. A sealed cell was not acceptable for these critical applications.
With her background in computer modelling and physical chemistry, Kathryn was able to develop a model and numerical tables that would allow customers to convert the open circuit voltage of a VRLA battery to the acid concentration and battery state of charge. She was also able to use thermodynamic data from the literature to correct the state of charge for the internal battery temperature.
“To maintain my skills and increase my knowledge of lead-acid batteries, I began reading articles in the Journal of Electrochemical Society on corrosion reactions at the lead-acid positive grid by Paul Ruetschi, Jeanne Burbank, Detchko Pavlov, and others. With electrochemists from local universities, I also founded a local chapter of the Electrochemical Society.”
In an evening graduate course on corrosion at the Colorado School of Mines, Kathryn learned about potential-pH (Pourbaix) diagrams. Since positive grid corrosion reactions are dependent on both sulfate (S) and hydrogen (H) ion concentrations at the corrosion interface, she now developed a three-dimensional potential/pH/pS diagram that could be used to better understand and reduce the corrosion of the positive lead grids.
“In 1977, after about five years in Denver, my husband wanted to accept a position as a minister in Wisconsin. So I applied for and accepted a job at Globe-Union, a large battery company in Milwaukee that became part of Johnson Controls. I worked there for nearly 15 years, first as a research scientist and then, beginning in 1980, as manager of the battery research group. We worked on many different kinds of lead-acid batteries, including flooded, gelled and acid-starved designs for all types of automotive, stationary, and portable applications.”
At Gates, Kathryn had worked on a project to determine how much phosphoric acid should be added to the VRLA battery electrolyte and had presented a paper on her results at an Electrochemical Society meeting. Phosphoric acid was added to lead-acid gel batteries to increase their cycle life. She used cyclic voltammograms to study the effects of phosphoric acid on lead battery reactions. Based on her cyclic voltammetric data, the amount of phosphoric acid added to the Gates cells was reduced to a very low level.
At Johnson Controls, she continued to study phosphoric acid effects on the positive electrode in lead-acid batteries and published additional work on the subject.
In 1980 the Electrochemical Society Battery Division presented Kathryn Bullock with its research award for this work.
Kathryn’s research group was partially funded by the US’ Department of Energy to work on electric vehicle and load levelling batteries. The battery research group also supported development work on nickel-metal hydride and zinc-bromine batteries. She began to file patents at Johnson Controls on her ideas of ways to improve lead-acid battery performance and on ways to decrease battery production times.
One of her first projects was to find an alternative way to make a dry-charged battery. Johnson Controls had a method of charging an acid-filled battery and then dumping out the excess acid and centrifuging the battery to eliminate as much moisture as possible. Unfortunately the shelf life of this battery was not as good as for dry-charged batteries due to the residual acid left in the battery.
“So I tried putting a sealed plastic bag of highly concentrated acid on top of the battery electrodes after the centrifuging process. Since concentrated sulphuric acid is a good desiccant, water from the battery self-discharge process would slowly move from the residual acid in the battery through the wall of the plastic bag. The highly concentrated acid in the bag was gradually diluted and the battery’s open circuit voltage remained high.
“I thought that this approach would extend the shelf life of the positive plate and that I could easily add the diluted acid to the battery by puncturing the bag. When I tested the battery after about a year on the shelf, it still had a high voltage and the positive plate had good capacity, but now the negative plate limited the battery’s performance.
But from this experiment I did learn a useful lesson: If one electrode doesn’t fail, the other one will! Paying attention to chemical reactions in both positive and negative electrodes and the interactions between them is still very important if we want to understand and predict failure modes in VRLA designs for hybrid electric vehicles.”
The Johnson Controls battery division had a very good engineering department, along with a technical library, a materials research group and an analytical group that provided very good support for battery research and development. Many of their projects were cosponsored by the US’ Department of Energy. The two built a new R&D laboratory and worked on lead-acid, zinc-bromine, and nickel-metal hydride battery development projects for applications such as load levelling and electric vehicles.
One of those whom Kathryn brought into her R&D Group at Johnson Controls, was University of Texas PhD, George Brilmyer. “When Kathryn hired me it was back in the early 80s, not too long after Johnson Controls had purchased Globe Union. I was new to the industry, one of the new additions to an established R&D group that she was expanding,” he says.
“What I admired about Kathryn was that she was not only as a very good scientist but was also an outstanding manager. Yes, she did some ground breaking work to understand the functioning of non-antimonial alloys, but she and Bill Tiedemann assembled a top notch R&D team and soon built a new world-class R&D laboratory (that has now morphed into JCI’s Battery Technology Center).
“Back then we were working on many of the right subjects such as grid corrosion, battery thermal management, EV batteries, grid design, plate curing and even load-levelling. I’ll never forget our work designing the new lab and purchasing some of the first computer controlled battery cyclers from Bitrode (and it was all done without email)!
Determination and learning
As continuing education was also important to their success, Kathryn taught several short courses to her staff. The Electrochemical Society had a Chicago local section, but it was a long, cold evening drive in the winter.
“So we organized a local Wisconsin section with alternating meetings in Madison and Milwaukee. One meeting each year was a symposium of papers given by local graduate students. I also accepted invitations to speak annually at a graduate course in batteries at the University of Wisconsin in Madison and to teach a course in electroanalytical chemistry at Milwaukee. These activities helped us to maintain an excellent research group.”
In 1991, AT&T Bell Labs asked Kathryn to lead the move of their battery group from Texas to New Jersey. The AT&T power systems group had already moved to Texas, but most of the battery group in New Jersey did not want to move. Fortunately, she was able to retain a few of the battery engineers in New Jersey and hired others in Texas. Her husband had earned a masters in social work at the University of Wisconsin and found a position near Dallas.
“At AT&T I had an opportunity to get more experience in systems engineering and worked closely with systems engineers and battery companies to develop new battery designs. AT&T also agreed to let me accept a nomination to run for vice-president and then president of the Electrochemical Society.”
They worked in Dallas for five years, until Bell Labs became part of Lucent Technologies. At that time Medtronic, Inc invited Kathryn to lead a group developing an aluminium electrolytic capacitor design and factory and designing new lithium primary batteries for implantable medical equipment.
In 1996, she was awarded the Gaston Planté medal — perhaps the most prestigious award in the lead acid battery business.
At the end of 1999, she accepted a position as executive vice president of technology at C&D Technologies in Philadelphia.
In 2003, Kathryn Bullock founded a consulting business called Coolohm, Inc where she has been at the cutting edge of various new projects since.
For example, in some new lead-acid battery designs, higher levels of carbon are being added to the negative plate materials. In other designs, half of the negative plate is carbon and the other half is lead. This concept was developed in Australia and is being produced at Furukawa in Japan and at East Penn Manufacturing Company in Pennsylvania.
The lead/carbon negative plates and lead dioxide positive plates form a combination of a capacitor for power at high currents and a battery for energy at lower currents in the same module. These batteries are working well in some hybrid electric vehicles.
She says it is nowadays as important to understand the chemical mechanisms of carbon in the new battery designs and applications as it has been to understand the chemical effects of oxygen and hydrogen reactions, higher acid concentrations, other new additives, new separator components, and novel cell designs on the VRLA battery.
“The Advanced Lead-Acid Battery Consortium has supported much of my recent work in defining the effects of carbon materials on the mechanisms and failure modes in this new system.” In October she organized a symposium with Patrick Moseley at the ECS meeting in Boston and presented a paper on the chemical effects of adding more carbon to the negative plate of lead-acid batteries for high power applications such as hybrid electric vehicles and wind energy storage.”
She also teaches a graduate course in Electrochemical Power Sources at Villanova University. Husband Ken continues to work as a priest in the diocese of Philadelphia.
She is the author and co-author of more than 60 scientific papers, chapters and books and has 11 US patents in battery, fuel cell and capacitor technology.
Since 2002, she has also been a Heritage Councillor for the Chemical Heritage Foundation, a non-profit organisation whose aim is to strengthen the public understanding of chemical sciences and technologies; increase the flow of the best students into the chemical sciences and chemical process industries; and to instil in chemical scientists and engineers a greater pride in their heritage and their contributions to society.
She is a member of the National Academy of Sciences Committee on the review of the FreedomCAR and Fuel Partnership.
A committed Christian, her life has been based on the belief that science and faith are not incompatible and our duty is to push back the borders of our understanding as far as we can — and impart that wisdom and knowledge to others.