Better batteries for electric cars

Mar 14, 2011
This is a microscopic representation of the battery using the BEST simulation software. The porous electrodes can be seen on the right and left. Credit: Fraunhofer ITWM

The breakthrough with electric cars is a long time coming -- not least on account of their key component, the battery. Lithium-ion batteries are still too expensive and their range too limited. New materials should pave the way for better batteries. Simulation software from researchers is helping speed up the development process.

Electric cars are the future – a view shared by government and the automotive industry alike. The German federal government aims to establish Germany as the lead market for electromobility. By 2020, a million passenger cars with an electric drive should be on the roads in Germany. The prospects of achieving that aim look good: As the ADAC, the German motoring organization, found out in a survey, 74 percent of those surveyed would buy an electric car if they did not have to compromise in terms of cost, comfort and safety. Consumers are not willing to compromise one iota when it comes to range.

Around one third of drivers are looking for a range of at least 500 kilometers. And here is the crux: A lack of charging stations and limited battery life have so far prevented compact electric vehicles from going mainstream. The lithium-ion batteries used by most automakers are simply too heavy, too expensive and go flat too quickly. should improve the performance, service life and safety of the energy storage device, yet the development of these kinds of materials is time-consuming and costly. In the Fraunhofer System Research for Electromobility (FSEM) project, researchers from the Fraunhofer Institute for Industrial Mathematics ITWM in Kaiserslautern are developing software to simulate lithium-ion batteries, which should in turn speed up this process and make it more efficient. The new software is dubbed BEST, short for Battery and Electrochemistry Simulation Tool.

A consists of two porous electrodes kept apart by a separator filled with electrolyte. Lithium ions flow between the electrodes when the battery is charged and discharged. "Battery performance depends on the materials used in the components. These materials need to work in harmony with each other," explains Jochen Zausch, a scientist in the Complex Fluids group at Fraunhofer ITWM. "Various material combinations can be simulated using our software, enabling us to come up with the ideal mix. The kind of trial-and-error testing done in the past is no longer necessary."

The Fraunhofer ITWM researchers have managed to simulate on macroscopic and microscopic level the entire battery cell as well as the transport and reaction processes of the lithium ions themselves. "We can show the microscopic structure of the electrodes. Every individual pore measuring 10 micrometers can be seen – something none of today's off-the-shelf programs can do. The position and shape of the electrodes can also be varied," says Zausch. By resolving the structure of the electrodes in three dimensions, parameters such as lithium ion concentrations and current density can be calculated. For these computations a specializes "Finite Volume" code is used that was developed and implemented at the ITWM. The distribution of the current flow provides an indication of heat production in the battery. Therefore, the software can pinpoint possible hotspots that may overheat and can lead to ignition of the battery. Aging effects can also be assessed using BEST. After all, temperature development within the affects its service life. The scientists intend to upgrade the program to include aging models which would make these kinds of studies even easier to conduct.

"Ultimately, BEST should help both automakers and manufacturers of electric storage devices to build robust, safe batteries with greater range and, at the same time, improved acceleration," says Zausch in conclusion. The software can be seen at the Hannover Messe from April 4 to 8 on the joint Fraunhofer booth in Hall 2, Booth D22.

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GSwift7
2.5 / 5 (4) Mar 14, 2011
if they did not have to compromise in terms of cost, comfort and safety. Consumers are not willing to compromise one iota when it comes to range.

Around one third of drivers are looking for a range of at least 500 kilometers. And here is the crux: A lack of charging stations and limited battery life


Ahh, anybody besides me notice what they are deliberately NOT mentioning anywhere in this article?

Hmmm?

Wait for it..

Charging time? I don't think anybody wants to drive 300 miles (500 km) and then stop for several hours to charge before carrying on with the business trip, family vacation, or police patrol. Swapping batteries isn't a viable answer either. Imagine the trucks driving around from one place to another, keeping the supply of charged batteries evenly distributed, otherwise you could get to a swap site and they could be out of charged packs. Batteries are a tough sell, unless you can charge them really fast. Maybe supercapacitors, maybe.
mrN
4 / 5 (4) Mar 14, 2011
I don't think anybody wants to drive 300 miles (500 km) and then stop for several hours to charge before carrying on with the business trip, family vacation, or police patrol.


Are you serious? If one drives 6,25 hours one probably needs if not sleep then good walk on the park. Nobody wants to drive continuously 1/4 of day or more.

Swapping batteries isn't a viable answer either. Imagine the trucks driving around from one place to another, keeping the supply of charged batteries evenly distributed, otherwise you could get to a swap site and they could be out of charged packs.


Simple question please: How do you know? Are you expert on the mater? Transforming car batteries to place to place will be part of system and drivers will of course transfer batteries all by themselves. System as whole will be predictable and can be manipulated with prices. Of course swapping will be quite rare.
TrinityComplex
4.5 / 5 (2) Mar 14, 2011
Long distance relationships, people driving to see family and friends, ski trips. All are examples of things I have driven over 400 miles for, wanting to get there as fast as possible. I regularly make a 750 mile trip, only stopping to fuel up, stretching my legs as I pump the gas. For someone like me an electric car would not yet be a viable option unless I'm okay with spending significantly less of what little time I usually have at my destination. This might just be the required paradigm shift, but I would prefer to be surfing for the 6+ hours it would take to charge an EV. What really sucks is that I would like to buy an EV, because I think it's more environmentally responsible, and the air quality where I live is horrible.

As far as swapping batteries at gas station like locations, they very well could run out of charged batteries if they are busy enough, forcing people to wait when they may not have time to. It's running out of CHARGED batteries that's the concern.
GSwift7
1 / 5 (1) Mar 15, 2011
Are you serious? If one drives 6,25 hours one probably needs if not sleep then good walk on the park. Nobody wants to drive continuously 1/4 of day or more


In the United States we drive 7-8 hours frequently. My brother lives 7.5 hours away, for example, and we visit several times a year. Salespeople often spend most of their day driving from one customer to another. Police cars are driven almost constantly, 24 hours a day, since two or three different officers can share the same car (same for many commercial vehicles). A range of 500 km just is not far enough for most Americans. For instance, I make frequent trips to Charleston, Charlotte and Greenville wich are each about 250 km away from me. With a round trip distance of 500 km, that would not leave any safety margin for me. If I had to detour because of a wreck then I would not be able to make the trip. Also, the 500 km range is only when the batteries are new. They get worse with age.
GSwift7
3 / 5 (2) Mar 15, 2011
As far as swapping batteries at gas station like locations, they very well could run out of charged batteries if they are busy enough, forcing people to wait when they may not have time to. It's running out of CHARGED batteries that's the concern.


It would be a hassle too, since current US laws would prevent normal people from changing their own batteries. Under OSHA rules, you need to wear heavy rubber gloves up to your elbows, an apron, steel toed leather shoes and a face shield when working with large rechargable batteries like the ones on forklifts and electric cars. Some states still don't allow self-service gas pumps due to safety issues. Imagine the average mechanical idiot trying to hoist a 500 lb battery pack filled with acid on his own? Not gonna happen.

How do you know? Are you expert on the mater?


No, but I found several expert appraisals in five minutes on Google. I don't need to be an expert because I can read the work of people who are. Try it.

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