Could Solvent-Free Manufacturing Technology Help Make Lithium Polymer Batteries a Reality?

I had a chance to chat with Dr. Klaus Brandt, EVP of Lithium Technology Corporation (Ticker symbol LTHU.PK). LTC has been in the business of Lion battery development for over 10 years. They are focused on large energy content / high power applications, primarily using lithium polymer technologies.

The Company was formed 4 years ago through a merger of a German battery startup called and LTC. Dr. Brandt is the Executive Vice President of LTC and Managing Director of their GAIA GmbH subsidiary, joining GAIA in April, 2005. A 25 year battery industry veteran, Gaia is his 5th battery company. He previously worked for Duracell (US) and VARTA (Germany), Moli Energy & Ionity. He holds a PhD, Physics from Tech Inst of Munich.

They haven’t disclosed much on their customers, but are focused on the military markets (especially for unmanned vehicles, like UAVs, they have one announced participation with Phoenix), and in niche industrial markets like robotics. The holy grail opportunity, of course is the EV, HEV and Plug-in hybrid automotive markets, where LiOn technology has an opportunity to displace NiMh, if it can drive costs down far enough. So far LTC has been working on early demonstrator projects in this area, but doesn’t appear to have hit the big one yet.

A quote from a recent press release on some of LTC’s activities in the plug-in hybrid sector.

“LTC has powered a project in conjunction with Innosys Engineering in which a four passenger Daihatsu Cuore was converted into an electric car using the lithium-ion batteries and a three-phase asynchronous electric motor. The battery, built with cells manufactured by LTC subsidiary GAIA, has a capacity of 25 kWh and an approximate highway range of 180-200km (100-125 miles) at 90-100km/hr (56-60 mph). These results are similar to the expected performance of the recently announced Volt slated to be made available by General Motors in 2010. “The technology is here today. LTC has it, and we’ve demonstrated it,” says Dr. Brandt. “Price is the biggest factor holding back the production of these more environmentally friendly, fuel efficient vehicles. By committing to work together, the auto manufactures and battery companies can bring the cost down and make cars like the Volt an affordable reality for the consumer.” LTC’s technology was recently highlighted in a video produced by Plug-In Partners, a national grass-roots initiative to demonstrate to automakers that a market for flexible-fuel PHEVs exists today. The full video discussing the economic and environmental benefits of PHEVs can be viewed on the Plug-In Partners website.

The piece featured a project in which LTC provided cells to the University of California, Davis Hybrid Electric Vehicle Group for the conversion of a Chevy Equinox to a PHEV as part of the Challenge X: Crossover to Sustainable Mobility engineering competition. The lithium-ion battery has the same capacity as the original metal hydride battery but with half the weight. The battery can be charged by either the internal combustion engine (ICE) or a standard AC household electrical socket and can drive over 40 miles on the overnight electrical charge. The converted vehicle has a fuel economy of 36 mpg in the city, and 38 mpg on the highway, as compared to the original Chevy Equinox range of 19 mpg city and 25 mpg highway.”

As a result of the merger with Gaia, Arch Hill Ventures, NV, the venture capital firm behind Gaia, now has a dominant stake in the company. I couldn’t find much information on Arch easily available, though.

The company trades over the counter in the US, and has struggled financially (revenues are around $2 mm/year), and it loses money, and the stock price for the last several years has reflected this. Of course, it doesn’t help that the company doesn’t seem to have filed a 10-K or 10-Q since May of 2006. In December the company earned a reprieve raised $3 mm in a Series C Preferred Stock at a valuation on the order of $23 mm, and converted about $2.4 mm in debt.

In Germany the company is manufacturing cylindrical cells, and packaging them into batteries, and doing some prod development, along with EU sales. In the US Dr. Bradnt says they do a limited production of flat cells, the US sales and marketing, as well engineering and assembly of batteries for American customers.

But aside from all that, I asked Dr. Brandt to give me a summary walk through of the technology, what makes it neat, and what the cost and performance advantages are.

The brief from their website:

“LTC’s unique technology allows for the production of very large cells with a high capacity and high power capability.

LTC’s wholly owed affiliate GAIA Akkumulatorenwerke in Nordhausen, Germany employs a unique patented extrusion process for producing electrodes for lithium ion cells. This process is environmentally friendly (no solvent) and eliminates the need for expensive explosion proof coating and solvent recovery equipment. Using high speed winding and a unique assembly technology, large cylindrical cells are manufactured. In our Plymouth Meeting facility, we have the capability to build large footprint flat cells and stack them to form large batteries. Our proprietary technology includes critical composition, processing, and packaging aspects of the battery. Our coating, lamination and extrusion know-how enables us to achieve uniformity and consistency through a range of application techniques. Batteries for the consumer, transportation, and industrial markets require different electro-chemical systems that we believe can be easily accommodated by our extrusion process.”

According to my conversation with Dr. Brandt, LTC has two core technologies. The first is this extrusion process for a part of the cell manufacturing for either LiOn or Lithium Polymer batteries. The uniqueness is a way to avoid the use of large amounts of solvents in the process of manufacturing electrodes from electrode powders.

Normally, you make electrodes by a coating process. Taking electrode powders and mixing them in an organic solvent with has a binder and any additives dissolved in it. This results in a fairly viscous slurry with typically more than half organic solvents . Then battery manufacturers typically use a coating process (usually a printing type roller process or some sort of foil through narrow slit, controlling deposition quality mechanically) to coat the slurry onto a current collector, usually a thin metal foil, and in a post process step heat the electrode to evaporate the solvent, which by volume is often greater than the active material.
Typically the make-up of the solvents used is key intellectual property for the battery manufacturer, but most are highly volatile and toxic chemicals, and need to be recycled in some sort of a closed loop system that is generally equipment and energy intensive (read costly, and not very green).

The LTC process is different. LTC runs an extrusion process as follows – make the electrode powders into mixture of powder materials directly with a special polymer binder, which flows under some pressure and temperature, and extrude the mixture into a film sheet. The process runs in the range from 200-300F up to 350-400F, and uses off the shelf plastic extrusion equipment. As second step, LTC then laminates the film to the foil. The lamination allows good control of all kinds of properties. The whole thing is roughly similar to low temperature polymer membrane construction process.

The trick is the mix of the polymers. If mix isn’t right you can’t keep mechanical consistency or can’t control thickness of the film and uniform distribution of the components. The polymer mix also affects the binding properties.

They claim the process does not really affect the cell manufacturing or the electrolyte relative to other processes. And Dr. Brandt says it has applicability for lithium ion as well as lithium polymer.

The advantage – no solvent extraction, cleaning, and recycling process equipment, and reduced energy use. Basically a more efficient, greener, cleaner process. LTC estimates their process can reduce a cost structure on the order of 5-10% improvement over conventional technology, a big improvement in battery manufacturing techniques.

The main challenges are those similar to all lithium ion and lithium polymer battery manufacturers. In the area of automotive and HEVs, they need to address cost. Scale of production is obviously a main cost down concern for LTC at this point, but materials costs are a close second. Like all lithium polymer technologies, the materials in general are still quite high.

On the performance side, Dr. Brandt walked through another interesting technology development.

They are able to build relatively large systems at a similar power density and power rate to smaller systems compared to other manufacturers, especially useful in areas like submarine and UAV batteries.

They also get high power and excellent charge/discharge rates – on some cell types up to 80% of the energy in 2 – 3 minutes.

The trick here is LTC’s technology to manage the thermal issues in the way they make the electrical connections between electrodes and terminals in the wound cells. LTC essentially makes electrical connections at every turn of a wound cell, directly connecting each cell to the terminal, using massive (relatively) terminals. They do it with a special trick they have developed to easily allow a large number of the multiple connections.

All in all, a fascinating story. One I will have to follow closely and see how well the company pulls through its recent financial straits.

Author Neal Dikeman is a founding partner at Jane Capital Partners LLC, a boutique merchant bank advising strategic investors and startups in cleantech. He is the founding contributor of Cleantech Blog, and a Contributing Editor to AltEnergyStocks.com.

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