Transforming battery technology
From the nickel-iron batteries made for the first electric automobiles in the early 20th century— to the efforts of today’s engineers and scientists to improve capabilities — the potential applications for batteries have grown far beyond vehicles and raise critical issues.
A significant part of everyday life concerns the batteries in our cellphones and computers. For all their importance, however, fundamental problems concerning battery technology are waiting to be solved. One of these is time. “We’ve been able to move electricity over space, but not over time,” said James Greenberger, director of the National Alliance for Advanced Technology Batteries, referring to how easily electricity moves through wires. Efficiently and cost effectively storing energy over long periods of time for use on demand is the key question facing researchers. Answering this will fundamentally change battery technology and, consequently, many other facets of our lives.
According to Greenberger, the major issue in solving the time problem is how to store more battery energy in a lighter mass and smaller space for long durations. He called this quest the “gating challenge for most of the new technologies expected to impact human society over the next century.” To Greenberger, these innovations will affect batteries designed for automotive use, stationary grid storage, and on to thin film batteries to enable wearable batteries. In addition, not only will there be immense positive economic changes because of cheaper and more available energy, but also significant advances in medical devices and nanotechnology.
You can’t tell the sun when to shine
An ever-increasing amount of renewable solar and wind generation is making energy storage even more important, noted Colette Lamontagne, a director in the Energy Practice of Navigant Consulting Inc., a global management consulting firm. While replacing coal and gas generation with wind and solar can reduce emissions and offer other advantages, new problems arise. “You can’t tell the sun when to shine or the wind to blow, which makes it difficult to control how much and when electricity is distributed to customers,” Lamontagne commented. In the current system of centralized power plants, electricity is distributed on demand. Renewable energy is acquired intermittently and can’t be efficiently stored for many people to use when needed. Using batteries to store renewable energy makes it possible to be flexible in the amount of energy stored and when it is required. Writing in the Energy Storage Technology Review from Duke University Energy Initiative, Kyle Bradbury, Ph.D., postdoctoral energy fellow, proposed that “Efficient and economic energy storage, if implemented in the current power infrastructure on a large scale, could bring about some of the greatest changes in the power industry in decades.”
With renewable energy and the smart grid becoming more prevalent because of regulations concerning carbon dioxide emissions and coal production, the ability to store electrical energy economically to use on demand is becoming an even greater priority. “Energy storage has become a big player because of how electricity is changing,” Lamontagne explained. The shift in generating energy from oil and coal to solar and wind adds yet another extensive dimension to issues concerning battery technology.
Lynn Trahey, Ph.D., materials scientist at Argonne National Laboratory, agreed that battery storage goes hand in hand with renewable energy. She received a 2012 Northwestern-Argonne Early
Career Investigator Award for Energy Research to investigate new materials to improve the performance of anodes in lithium-ion batteries. “Renewable energy needs flexibility, and batteries are part of that equation,” she said, pointing out that specific chemistry-related problems affect a battery’s lifetime. “It boils down to the irreversible change in materials and side reactions,” continued Dr. Trahey. Anything less than 100 percent means a loss that will not be recovered.
Another issue in battery technology is matching batteries to the many ways people use them. Because batteries offer so many different applications, the specific requirements of each demand distinctive technologies and chemistries. Ralph Brodd, Ph.D., president of Broddarp of Nevada Inc., a consulting firm specializing in battery technology and the financial aspects of electrochemical energy conversion, reiterated that each battery application has its own performance parameters. “The requirements for starting cars differ from those in flashlights or cellular phones. Each application has unique requirements for discharge rate, charge rate, and temperature, and not all reactions are reversible,” he said.
Advancing battery capability raises another significant issue: how to prolong a battery’s life cycle and find costeffective and expedient ways to recharge it. “Primary batteries are used once and discarded,” said Dr. Brodd. But as he pointed out, however, the challenge becomes more difficult with rechargeable batteries that must reform the active materials in exactly the same chemical configuration that they had at the start. He cited this requirement as the reason reactions in battery chemistry are so few. Battery technology centers around the energy storage capability of a given set of chemicals. The materials inside a battery must not change during their use while storing energy. “Very few chemical combinations have these characteristics,” he said. “Not every chemical combination has high enough storage capability coupled with long life. Only a select few reactions are exactly reversible under all conditions.”
Adding in the cost
Summer R. Ferreira, Ph.D., is a senior member of the technical staff in the Advanced Power Sources Research and Development group at Sandia National Laboratories and currently tests stationary storage batteries for their cycle life and performance characteristics. She explained that her battery research on evaluating battery life is needed to understand if the amortization of the capital cost makes a technology a viable solution.
Dr. Trahey from Argonne National Laboratory concurred that one of the challenges facing battery technology research is making the results cost effective. “Researchers are working hard to balance both increases in energy and decreases in cost. An increase in energy doesn’t produce a decrease in cost,” she said, noting that the less-commercialized batteries are more complex, which adds to the expense. Eventually, battery technology research will show benefits such as lower costs derived from better energy storage for the grid and electric vehicles. This will lead to efficiency in grid storage and more electric cars. “It’s all part of the big picture,” she emphasized. “We need both storage and energy generation.”
Though there are many ongoing research projects into improving battery technology, the pertinent question is whether this research will lead to actual products. Dr. Trahey says progress is being made as a result of the research that now flows back and forth between battery manufacturers and national laboratories or university research labs. “A lot of battery manufacturers and enduser companies employ scientists who work with research labs and are paying close attention to research,” she continued, citing that much of the funding is jointly spread out across these sectors.
Addressing the timeline to turn current battery research into real products, Dr. Ferreira noted the wide spectrum of battery technologies and accompanying stages of investigation. Some findings are still in the lab while others are definitely moving from the lab into field projects, or are being commercially produced. Dr. Ferreira pointed to legislative pressure that is also bringing an added sense of urgency to battery storage research. For example, in October 2013, California passed a mandate directed to the state’s three big investor-owned utilities to cost effectively increase their capacity to store electricity by 2020.
Major advances and minor setbacks
To understand what is happening in today’s battery research, it’s helpful to understand how batteries have and have not changed. For example, lead-acid batteries, which were first produced in 1860, are still one of the commonly used types today. On the plus side, they can be manufactured in a wide variety of designs and applications at low cost. They have a low cycle lifetime, however, and do not perform well at high temperatures.
Major advances in battery technologies are happening despite these longstanding issues, and the time needed to solve them. The Web page of the Energy Storage Association, a national trade association for companies that research, manufacture, distribute, finance, and build energy storage products, states that “advances in technology and materials have greatly increased the reliability and output of modern battery systems, and economies of scale have dramatically reduced the associated cost. "Lamontagne explained that many of these advances were researched in the 1980s but were dropped because of funding issues. “Now it’s getting to a point where they are making advances and starting to prove that they can be commercially incorporated,” she said.
Dr. Ferreira added that advances in battery technology are “not just in the lab, but real companies are making real products.” She sees strong potential as more electrical vehicles are purchased; however, advances have their drawbacks for the time being. Today’s electric car batteries, for example, are still charged by energy taken from coal.
When asked what were the top advances responsible for these positive changes, Lamontagne cited advanced lead-acid batteries and lithium-ion batteries. “Lithium-ion batteries have a very large share of the market,” she said. “They are used in consumer products, electric vehicles, and stationary energy storage.” Though lead acid batteries have been around for a hundred years in commercial and industrial facilities and are very cost competitive, they have a shorter life cycle than other chemistries. On the plus side, advanced lead-acid technologies increase the cycle lives. Some full-scale systems of lithium-ion and advanced lead-acid batteries have been operating for three to five years.
Lithium-ion batteries are the battery of choice for computers and other portable electronic devices. Dr. Trahey says that researchers “hit the ball out of the park with the lithium-ion breakthrough.” And the research continues with the lithium anode battery. In an Aug. 2, 2014, article in USA Today, “Stanford Researchers Close to Battery Life Breakthrough,” Wendy Koch wrote that a team at Stanford University is researching a “lithium anode battery that might give electric vehicles a 300-mile driving range and triple a cell phone’s juice.” Predictions are that it will take three to five years before the product is available. The article indicated the advances that have been made in the push for a battery that can be used for portable electronics as well as storing solar and wind power. It stated that universities, start-ups, and major companies are working with new materials such as vanadium or are tweaking the lithium-ion battery that was introduced 20 years ago. In addition, the Stanford team is using nanotechnology to create a pure lithium battery to achieve lightweight and superior efficiency.
Moving beyond lithium-ion
The Joint Center for Energy Storage Research at Argonne National Laboratory is also researching new technologies that will allow batteries to store five times more energy than today’s batteries at one-fifth the cost. They propose to do this within five years. In other research at Argonne and elsewhere, Dr. Trahey cited metal (Li/Mg/Al/Zn) air batteries in which oxygen replaces the cathode rather than materials. The fact that it uses air gives it the ability to store far more energy than other battery advances, plus the weight is considerably reduced. But here, too, researchers must solve the problem of capturing and filtering enough air to produce the power needed. Another restraint is that metalair batteries are not long lasting, and thus the whole battery must be replaced.
Flow batteries are another advance in battery technology. Energy is stored in an electrolyte solution, giving the battery the capability to be scaled to meet both power and energy needs by balancing the ratio of the electrolyte in the system. It can also be recharged. “People think that flow batteries, such as vanadium redox batteries, are perhaps the most promising alternative battery technology,” cited Dr. Ferreira.
Indeed, a Jan. 8, 2014, article on the Harvard School of Engineering and Applied Sciences website highlighted research being conducted by a team of Harvard scientists and engineers into a “new type of battery that could fundamentally transform the way electricity is stored on the grid, making power from renewable energy sources such as wind and solar far more economical and reliable.” The article stated that this is research into a metal-free flow battery in which the electrochemistry of small carbon-based molecules called quinones is the basis of this new technology instead of the more expensive chemicals. Quinones can be easily found in crude oil and green plants — a most promising development that this research team will continue to test and optimize.