Sage Supplier: Battery manufacturer makes storing wind, solar energy possible
Provides missing link between renewables’ variability and all-day usability
October 11, 2011
International Battery, Allentown, Pa., designs and manufactures large-format lithium ion batteries—not for automobiles, but for renewable energy storage.
International Battery, Allentown, Pa., designs and manufactures large-format lithium-ion batteries—not for automobiles, but for renewable-energy storage (see Figure 1).
Large-format is a new class of battery, according to David McShane, executive vice president, business development and engineering, at International Battery. "Traditional packaged lithium batteries are about the size of a D cell regular battery. We have 70 times the capacity of those traditional batteries in one of ours, so we have a much larger building block to work with and a more convenient packaging format."
The manufacturer's large-format batteries are too large and powerful for a passenger car, but they are used to power large, multioccupant vehicles such as hybrid buses. Their primary use is for storage of renewable energy.
"With the advent of the smart grid, we're targeted much more on utility applications. This is the next generation of power delivery going forward," McShane said. Large-format batteries are used to integrate renewables (wind and solar) to make them more dispatchable as power sources to the facility or into the grid. The manufacturer provides energy storage systems for solar arrays around the world, he said.
International Battery's foray into large-format lithium-ion batteries involved importing batteries from China. However, the company quickly came to the conclusion that it had to take control and ownership of manufacturing the cells in the U.S. to control quality and cost, according to McShane.
The battery-maker has achieved ISO 9001 certification and is currently working toward ISO 14001 certification.
Going forward, the company developed its own techniques to process lithium to make the cells in the U.S. cost-effectively (see Figure 2).
Water-based, Nonhazardous Manufacturing Process
One of its cost-effective approaches is also a green approach. The manufacturer specializes in producing its batteries using a unique water-based manufacturing process that reduces environmentally hazardous solvents.
"We were looking for a more cost-efficient way of producing batteries. That was the No. 1 driver," McShane said.
International Battery works primarily with two types of lithium-ion chemistries: lithium iron phosphate and lithium nickel manganese cobalt. The manufacturer purchases its lithium material from licensed sources, combines them into a slurry to coat the aluminum or copper material on both sides, stamps the coated metal into electrodes, and then stacks the electrodes to make the battery (see Figure 3).
"So this is where our water-based process comes in," McShane continued. Traditionally, a toxic VOC solvent such as N-methyl-2-pyrrolidone [NMP] is the carrier to convert the lithium powder into a solution to coat the electrodes, he explained. The company's unique water-based manufacturing process reduces NMP and reduces costs.
"Part of International Battery's intellectual property is knowing how to combine active lithium powders with water as a carrier and to make a consistent slurry so that we can coat electrodes in a consistent and high-quality fashion."
Being able to use water as the carrier is a big cost-saver, because not only is the NMP solution expensive, it must be recovered to comply with EPA health and safety protection regulations and also for reuse, McShane said. "It's also very challenging," he added. "The quality control has to be incredibly high so that when the battery is tested, it will retain and produce the same amount of energy from cell to cell. It must meet stringent specs and be within tight tolerance," McShane said.
Battery Types
Lithium-ion electrochemistries are not all the same. International Battery produces several different cell capacities and electrochemistries in large format, McShane said. The 160-Ah lithium iron phosphate cell has proved to be a workhorse. Those two tend to fit most applications best. The manufacturer is continuing research and development on a range of battery capacities and electrochemistries.
"Although the lithium iron phosphate chemistry is one of the lower-density lithium types, it is by far the safest and therefore the best choice for power delivery applications," he said.
Lithium iron phosphate also is benign in terms of maintenance requirements in that it does not contain acid or need watering, McShane said. "We package an active balancing system, or battery management system, to make sure it has maximum available capacity. It can run the entire capacity range, from 100 percent to zero, and gets a long cycle life. So it matches up very well with utility requirements," he said.
One of the batteries the company built is a 27-kWh, 1-hour unit for participation in the AEP's Ohio gridSMART® community energy storage program. Two- and three-hour units are in development. These batteries are placed in an oil-filled container and installed underground where the temperature stays relatively constant to stabilize the temperature. The oil enhances thermal management, he said.
The manufacturer has had extensive independent testing performed on its batteries. One of the industry concerns is a thermal runaway event, McShane said. "There is a whole range of lithium-ion electrochemistries. A laptop computer cell is something very different, and that was the electrochemistry that was causing an internal short circuit, generating heat and causing thermal runaway events. We haven't seen those types of events take place with lithium iron phosphate. That's why we do those impaling tests and overcharging tests and things like.
"Safety is paramount," McShane added. "We want to make sure that we put extremely safe products out in the field for our customers. We're proud of the safety and energy storage performance of our lithium iron phosphate batteries.
"This means that system design and packaging for the environment are more of a challenge than working with the battery itself. The building block of the energy storage device is only one piece. Customers want energy storage systems; almost 50 percent of the challenge is going from cells to systems," McShane said.
Battery's Role in Solar, Wind
Energy storage is used for integration of wind and solar energy into the power system to make it more dispatchable as power sources, McShane said. Batteries can level off the variability of wind and solar energy generation. "Solar has a prescribed profile. You don't get any solar power at night. And you get power from the wind only when the wind blows.
"One of the big issues for wind generation is that there's a minimum and maximum ramp rate at which the utility can acceptably integrate energy generated by the wind. That's where power storage helps out, because if you get a sudden gust of wind or a storm front comes in and the turbine starts to overproduce, you can dump some of that energy into the storage system. Or, when the wind drops suddenly, power storage can pick up that slack and smooth off that ramp rate when the generator comes offline. Ramping is a big deal in wind energy," he said.
"So energy storage helps to solve problems like that on the utility network and the smart grid. It won't be able to store all the energy, but it certainly can store some of it."
A range of supervisory controls are available to manage the energy storage system. "With a battery and a four-quadrant power converter, our customers can either charge the battery with the power generated from the on-site solar or wind power or discharge it. That's real power.
"Once they have control of that, there's a whole range of things they can do, depending on the priority. They can manage the energy storage system to various states of charge to do things like low-level absorption of solar power, or correct power factor on the grid side."
On the customer's side of the meter, International Battery is working with solar and wind energy equipment integrators on achieving net-zero-energy homes. The solar panels and wind energy generators, when integrated with the company's energy storage, an inverter, and a communication component, can produce enough energy for the home's use. The concept is that over the course of a year, the net annual consumption of electricity is zero; thus, net zero.
Industry Segment Applications
The company's energy storage systems have applications in distributed energy, buildings, transportation, and the military.
Distributed Energy Storage. International Battery is supplying batteries to utilities, which install battery systems at network extremities, or at the local distribution transformer that serves four or five homes. This is called community, or distributed, energy storage.
"This presents several power quality improvements. The battery can absorb solar energy collected on-site and help reduce the overall load from the utility. So, if there were a network outage, that energy store could keep homeowners blissfully unaware of a problem for a period of time. It can extend the life of a local transformer by leveling its load so it doesn't overheat," McShane said.
Similarly, bulk energy storage systems can store several megawatt-hours of energy, co-located at a local substation to help offset peak demand, for example.
Adding energy storage in certain tight feeder areas helps prevent the overloading of circuits. Also, energy storage provides the utility with capital deferral, so it can see how and where the load is going to grow before upgrading the infrastructure," he said.
Military. The battery systems are protecting the military as well. "Taking fuel out to remote bases risks the lives of the troops that have to transport the fuel. Costs can run between $30 and $300 a gallon. So if the military can support forward-operating locations without those supply chain burdens, there are a lot of advantages to that. It's heavily investing in the combination of renewables with energy storage to see how they can free themselves up from gasoline supply chains."
Transportation. In an interesting side note, the bulk energy storage International Battery produces may help usher in the plug-in electric vehicle (PEV) age more readily. Reportedly, in some regions of the country, their introduction is being delayed because local utilities are concerned about being able to supply enough electricity for them. Bulk storage of on-site renewable energy can help resolve that issue.
Building. Because the company's lithium-ion batteries contain no acid, they can be placed inside commercial buildings and homes without safety concerns. Recently International Battery was selected by an integrator to provide an 8.2 kwh lithium iron phosphate battery to store solar-generated energy for a net-zero demonstration home at the Philadelphia Navy Yard's Clean Energy Innovation Hub (see Figure 4).
Next-generation Power Delivery
McShane predicts that energy storage will have a large and important role to play in the future, as demand for energy increases. "There's an ever-increasing number of electrical loads—iPod®s, cell phones, computers, electric vehicles—so there's an ever-increasing demand on the electricity infrastructure. It doesn't matter that they're small. The population of these things is enormous, and they sit there consuming electricity all the time.
"Utilities were originally set up as unidirectional, so energy generation would always flow one way from a centralized power station out toward the extremities of the network and into factories or homes or commercial buildings," McShane said. "With renewables cropping up everywhere and people installing solar roofs and things like that, power can be generated from multiple locations. This can cause instability. Energy storage can help stabilize this.
"To be able to use energy storage to level out the demand and consumption peaks and valleys is a huge deal," he added.
"One of the bigger questions for the future is not really 'Are we going to be able to generate enough energy?' It's 'How are we going to be able to utilize our aging infrastructure to deliver that energy, wherever it's generated from, to the point of load where it's going to be used?' We have to find a way to make our delivery system more efficient and more robust going forward," McShane said.
Photos courtesy of International Battery, 6845 Snowdrift Road, Allentown, PA 18106, 610-366-3925, www.internationalbattery.com.
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