Green Patent Blog®

Electrovaya is an Ontario, Canada company that makes advanced batteries and battery systems.

Last month Electrovaya announced that it was selected by Chrysler as the battery supplier for the carmaker’s Ram plug-in hybrid electric vehicle demonstration program.  The Ram PHEV will use Electrovaya’s 12kWh lithium ion battery.

One of Electrovaya’s major innovations is its SuperPolymer brand battery technology, which the company’s web site calls “a novel nanostructured lithium ion polymer technology platform.”  This technology provides faster, more efficient transport of lithium, and therefore greater energy density, according to Electrovaya.

According to Electrovaya’s web site, the company has over 150 patents and pending applications worldwide.  One key patent is U.S. Patent No. 7,588,862 (’862 Patent), which relates to the polymer technology.

The ‘862 Patent is entitled “Composite polymer electrolytes for a rechargeable lithium battery” and is directed to a composite electrolyte for use in thin plate rechargeable lithium batteries.  The electrolyte may be a solid laminate or a separator sheet to act as a barrier between the positive and negative electrodes of the battery.

A separator embodiment comprises an inert porous or micro-porous polymer laminate (12) coated with a polymer coating (14) containing a dissociable lithium compound.  The polymer coating is on the exposed surface of the laminate (12) and, during the coating process, partially flows into some of the pores (15) of the laminate (12). 

The separator could have just one face of the laminate (12) coated with the second polymer (14), as shown here, or could have both faces coated. 

The portion of unfilled pores (15) can be filled with a desired lithium salt containing organic solution (16).  Electrodes (18, 18′) are in contact with the separator laminate (12).  Current collectors (20, 20′) are located on the external surfaces of electrodes (18, 18′).

According to the ‘862 Patent, existing solid polymer electrolyte laminates had higher concentrations of dissociable lithium ions, but they frequently had low mechanical strength. 

The patented electrolyte boosts a battery’s energy density by increasing the concentration of dissociable lithium ions per unit volume in the electrolyte while maintaining the mechanical strength of the laminate:

It has now been found that the amount of dissociable lithium ions can be increased without increasing the thickness of the electrolyte, and simultaneously providing desirable mechanical strength and integrity…

An interesting article from Distributed Energy magazine discusses a methane gas-fed fuel cell power unit developed by diesel and gas engine maker Wartsila.  According to the article, the Finnish company’s WFC20 is the first solid oxide fuel cell unit run on methane rich landfill gas.

Wartsila has finished the first phase of its validation program for the fuel cell unit, which has been in successful operation for more than 1500 hours. 

Wartsila owns several international patent applications relating to power plant technology, including combined cycle operating methods that recycle waste heat and a method of operating a combined fuel cell - piston engine plant.

The WFC20 is based on planar solid oxide fuel cell (SOFC) technology supplied by Danish fuel cell maker Topsoe Fuel Cell A/S (Topsoe).  According to Topsoe’s web site, SOFC fuel cells are the most efficient fuel cells available, recuperating the heat from its high operational temperature. 

Topsoe owns several international patent applications directed to its SOFC technology and fuel cell stacks, including Application No. PCT/EP2008/000527 (’527 Application).

The ‘527 Application is directed to an SOFC stack and clamping structure that uses a flexible sheet instead of conventional planar end plate flanges.  This reduces the amount of material needed for the fuel cell stack.  

The SOFC stack is inserted between two insulating blocks (12) (second insulating block on opposite side not shown).  The flexible sheet 15 is forced into a convex shape when in contact with the insulating end block 12.

According to the ‘527 Application, the flexible sheet 15 does not have to withstand bending forces so the mechanical tension lies in the plane of the flexible sheet, thus avoiding deformation of the fuel cell components.   The compressive force is obtained after clamping using nuts 8, springs 7 and tie rods 6. 

In April 2006 A123 Systems Inc. (A123), a Boston area lithium ion battery maker, brought a declaratory judgment action against Canadian utility Hydro-Quebec (H-Q) in federal court in Boston seeking declarations that A123 did not infringe U.S. Patent Nos. 5,910,382 (’382 Patent) and 6,514,640 (’640 Patent) and that the patents are invalid.  H-Q is the exclusive licensee of the ‘382 and ‘640 Patents.

The ‘382 and ‘640 Patents are entitled “Cathode materials for secondary (rechargeable) lithium batteries” and relate to host materials for use as electrodes in lithium ion batteries.  The patented materials provide a larger free volume for lithium ion motion that allows higher conductivity and therefore greater power densities.

In September 2006 A123 requested a stay of the Boston case pending the resolution of re-examination of the two patents in the U.S. Patent and Trademark Office (PTO).  The court dismissed the case without prejudice so the parties could subsequently move to reinstate it.

Also in September 2006, H-Q and the University of Texas (UT), which owns the ‘382 and ‘640 Patents, sued A123 for infringement of the patents in federal court in Texas.

This spring, after the PTO completed its re-examination of both patents, A123 asked the court in Boston to reopen its DJ action.  A123 argued that the Boston case should take precedence over the pending Texas action because it was the earlier filed case.

However, in a recent memorandum opinion (a123_memorandum.pdf) Judge Tauro of the U.S. District Court for the District of Massachusetts ruled that the Boston action could not be reinstated because A123 had failed to join the University of Texas.

Judge Tauro held that UT was a necessary party as the owner of the patents-in-suit because UT had not transferred all substantial rights in the patents to H-Q (the H-Q license contained some field of use restrictions).

Not only was UT not joined by A123, but UT could not be joined as a defendant in the Boston suit, the memorandum opinion held, because it is immune from suit.  Under the Eleventh Amendment, a federal court cannot hear a suit against a state without the state’s consent.

Last month A123 appealed (a123_notice_of_appeal.pdf) Judge Tauro’s order denying the motion to reopen the case (a123_order.pdf) to the Court of Appeals for the Federal Circuit (the appellate court that hears all patent appeals).

At least prior to A123’s appeal and Judge Tauro’s order, the Cleantech Litigation blog reported that the parties were trying to settle the suit. 

Eamex Corp. (Eamex) is a Japanese company that has developed a high energy density capacitor using a proprietary polymeric actuator with metal plating that serves as an electrode.

The capacitor and methods of making it are covered by U.S. Patent No. 7,169,822 (’822 patent).  The ‘822 patent is directed to a polymeric actuator (1) comprising an ion-exchange resin (2) in the form of a flat plate or film and metal electrodes (3a, 3b) attached to the surface of the resin by chemical plating techniques.

Lead wires (4a, 4b) provide an electrical connection between the electrodes (3a, 3b) and a power source (5).  The metal electrodes (3a, 3b) are insulated from each other, and application of a potential difference between the electrodes causes the ion-exchange resin product to bend or deform.

According to Eamex’s web site and this Greentech Media article, the electrodes of the patented actuator have greatly increased surface area, and the energy density per unit volume reaches up to 600 Wh/L, which is equivalent to that of a lithium-ion secondary battery.

Reticle, Inc. (Reticle) is a Los Altos, California startup that has developed a new carbon electrode material and process of making the material, which is ideal for use in ultracapacitors (see New Energy and Fuel article here).  

Ultracapacitors are used to store energy in applications that require storage of large amounts of energy and rapid energy discharge, such as electric vehicles. 

Ultracapacitors store energy through movement of electrons, i.e., separation of charged species as positive ions called cations migrate to a negatively charged electrode (anode), and negative ions called anions move to a cathode, or positively charged electrode.  The more ions that are attracted to their respective electrodes, the more energy the ultracapcitor stores.

There are two known ways to increase the number of ions attracted - boosting voltage and increasing the surface area of the electrodes.  This is where Reticle comes in.  The company’s patented process produces electrodes from granular activated carbon which have much greater surface area than any known electrode materials presently offered (see the inventor’s cogent explanation here).

Whereas typical processes consolidate carbon by pressing it into thin films, Reticle’s process applies pressure to the carbon material from all sides and obviates the need to add binders or adhesives.  This allows for better automation than other capacitor material, so the material can be machined into any size with lots of conductive surface area.

This picture shows one unique aspect of the resulting material, which the company calls “Reticle Carbon”:

That is, not only is the surface area greater, but all of the carbon particles remain connected to ensure that all the charge is distributed across the entire surface area of the material.

This table compares the specs and capabilities of two Reticle capacitors with those of a couple of other commercially available products:

Reticle Carbon also is a good material for desalination applications because the higher mass and surface area allows the acquisition of more ions before a regeneration step would be required.

Reticle’s manufacturing process and resulting carbon material are protected by a family of four U.S. patents:  U.S. Patent Nos. 6,350,520 (claims granular active carbon material made by a high temperature and pressure process), 6,511,645 (claims a process for producing carbon material by consolidating amorphous carbon using elevated temperature compression), 6,544,648 (claims a processed carbon material consolidated under elevated temperature and pressure) and 6,787,235 (claims a processed carbon material consolidated in a hot isostatic press under elevated temperature and pressure).

According to Jack Mastbrook, who does marketing development for Reticle, the company is currently seeking funding to ramp up operations.  But Mastbrook told me that Reticle already has a deal in place to sell its activated carbon to a major consumer products manufacturer, which plans to test the material as a replacement for batteries in its products.