Patents Assigned to Valence Technology
  • Patent number: 5744264
    Abstract: Non-aqueous solid electrochemical cells with improved performance can be fabricated by employing intercalation based carbon anodes comprising graphitized microbead carbon particles. When employed in a lithium electrochemical cell sufficient cathode material is employed to intercalate the anode active material to attain a specific electrode capacity of greater than about 372 mAh/g. The electrochemical cell has a cycle life of greater than 200 cycles, and has a first cycle capacity loss of only about 10% to 15%.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: April 28, 1998
    Assignee: Valence Technology, Inc.
    Inventor: Jeremy Barker
  • Patent number: 5744265
    Abstract: The invention provides a new positive electrode active material having increased capacity and a method for operating an electrochemical lithium cell or battery which has the new positive electrode active material composition. The positive electrode comprises first and second lithium-containing active materials which are different from one another. The invention provides the ability to overcome first cycle inefficiency typically observed when using a single lithium-containing metal chalcogenide by adding a small amount of a second lithium-containing metal chalcogenide, preferably lithium copper oxide.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: April 28, 1998
    Assignee: Valence Technology, Inc.
    Inventors: Jeremy Barker, M. Yazid Saidi
  • Patent number: 5738691
    Abstract: A method for removing plasticizers such dibutyl phthalate from the anode, cathode, and polymeric matrix components of an electrochemical cell precursor using an extraction solvent and ultrasound waves is provided.
    Type: Grant
    Filed: April 28, 1997
    Date of Patent: April 14, 1998
    Assignee: Valence Technology, Inc.
    Inventors: Jeremy Barker, Wade Guindy
  • Patent number: 5728489
    Abstract: A method of improving the structural integrity of polymer electrolytes of electrochemical cell by employing lithiated zeolites, and optionally, inorganic fillers selected from SiO.sub.2, Al.sub.2 O.sub.3, TiO.sub.2 and ZrO is provided.
    Type: Grant
    Filed: December 12, 1996
    Date of Patent: March 17, 1998
    Assignee: Valence Technology, Inc.
    Inventors: Feng Gao, Porter H. Mitchell, Jeremy Barker, Jeffrey Swoyer
  • Patent number: 5720780
    Abstract: A novel processing method provides a separator or electrode film demonstrating good physical properties and excellent conductive properties. Specifically, a binder of a suitable polymer, such as a polyvinylidene difluoride (PVdF) homopolymer, and a filler material such as silica or alumina are homogenized, such as by ball milling, to form a mixture free of solvents or plasticizers. An appropriate plasticizer, such as dimethyl adipate, is mixed into the binder and filler materials, and the resulting material is formed into a sheet. The sheet is hot pressed or melt processed at a temperature greater than the softening point but less than the melting point of the polymer mix. Electrode films can also be made using the method herein.
    Type: Grant
    Filed: November 4, 1996
    Date of Patent: February 24, 1998
    Assignee: Valence Technology, Inc.
    Inventors: Peikang Liu, Feng Gao
  • Patent number: 5714278
    Abstract: The present invention concerns forming a masked area on a porous separator material for use in a battery. Masked areas can be formed on the porous separator material with heat and/or pressure. The use of a masked area allows for easier alignment of the anode and cathode sections, such that edge effects do not occur. Edge effects, which result from the electrode sections having different surface areas, can cause differential current densities at the corners and edges of the electrode sections. This inhomogeneous cycling of the anode and cathode can cause premature cycle fade of the battery. The edge effects can also include dendritic growth of a lithium anode. The mask separator section can be connected to a solid electrolyte and a cathode section to form an assembly. This assembly can be later combined with an anode assembly to form a battery cell.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: February 3, 1998
    Assignee: Valence Technology, Inc.
    Inventor: Steven M. Mallinson
  • Patent number: 5712059
    Abstract: A battery which comprises a first electrode and a counter electrode which forms an electrochemical couple with the first electrode, and an electrolyte. The first electrode comprises graphite particles and the electrolyte comprises a solvent mixture and a solute. The solvent mixture comprises vinylene carbonate (VC) or substituted derivatives thereof and propylene carbonate (PC).
    Type: Grant
    Filed: November 1, 1996
    Date of Patent: January 27, 1998
    Assignee: Valence Technology, Inc.
    Inventors: Jeremy Barker, Feng Gao
  • Patent number: 5707760
    Abstract: A method of enhancing the thermal stability of electrolytic solvents containing lithium salts by the addition of carbonate additives such as lithium carbonate and calcium carbonate is provided. Electrochemical cells comprising electrolytes with the additives are expected to demonstrate improve performance and cycle life.
    Type: Grant
    Filed: December 9, 1996
    Date of Patent: January 13, 1998
    Assignee: Valence Technology, Inc.
    Inventors: Arnold M. Stux, Jeremy Barker
  • Patent number: 5700298
    Abstract: Increasing the percentage of the 3R phase present in graphite reduces the first capacity loss of anodes employing the so modified graphite. Conversion of 2H phase graphite to 3R phase graphite can be achieved by grinding graphite. Non-aqueous solid electrochemical cells with improved performance can be fabricated by employing intercalation based carbon anodes comprising graphite with high percentage of 3R. When employed in an electrochemical cell, the first cycle capacity loss of only about 10%.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: December 23, 1997
    Assignee: Valence Technology, Inc.
    Inventors: Hang Shi, Jeremy Barker, Rene Koksbang
  • Patent number: 5700300
    Abstract: The subject invention provides a three-step process for electrolyte deposition. A surplus of electrolyte pre-wet material, having a relatively low viscosity, is layered onto a dry, porous electrode. Surplus pre-wet material is mechanically removed from the surface of the electrode. This also removes bubbles or foaminess which has developed in the pre-wet material. The pre-wet solution is allowed to absorb into the porous electrode, and the surface is then coated with the high-viscosity electrolyte precursor. Curing or further processing of the electrode/electrolyte then continues with standard processes.
    Type: Grant
    Filed: August 12, 1996
    Date of Patent: December 23, 1997
    Assignee: Valence Technology, Inc.
    Inventors: Gert Jensen, Dale Shackle
  • Patent number: 5698338
    Abstract: Non-aqueous lithium solid electrochemical cells with improved performance can be fabricated by employing intercalation based carbon anodes and cathodes comprising Li.sub.x Ni.sub.y CO.sub.1-y VO.sub.4 wherein 0.9.ltoreq.X.ltoreq.1.1 and 0.1<y<0.9 as the cathode active material.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: December 16, 1997
    Assignee: Valence Technology, Inc.
    Inventors: Jeremy Barker, M. Yazid Saidi
  • Patent number: 5690703
    Abstract: A method for removing plasticizers such dibutyl phthalate from the anode, cathode, and polymeric matrix components of electrochemical cell precursors using carbon dioxide in the supercritical state is provided. The method forms porous polymeric structures that enhances the mass transport of ions in the cell which results in improved electrochemical performance.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: November 25, 1997
    Assignee: Valence Technology, Inc
    Inventors: Porter H. Mitchell, David A. Velasquez, Ib I. Olsen, Douglas B. Holmes
  • Patent number: 5674641
    Abstract: A battery module includes a number of electrically connected electrochemical cells. In a preferred embodiment, the battery includes multi-cell batteries in which electrodes are separated from different potential electrodes by a layer of polymer electrolyte. The battery module is formed from a number of multi-cell batteries stacked on top of one another, the electrodes of each multi-cell being electrically connected to one another, and the different potential electrodes of each multi-cell being electrically connected to one another so that a battery module having desired power characteristics is formed. The battery module includes electrically conductive spacers for electrically connecting tabs on the electrodes to tabs on other electrodes and tabs on the different potential electrodes to tabs on other different potential electrodes and for preventing damage to the tabs or the electrodes or different potential electrodes from bending the tabs excessively.
    Type: Grant
    Filed: October 29, 1992
    Date of Patent: October 7, 1997
    Assignee: Valence Technology, Inc.
    Inventor: Scot Stacey Cheu
  • Patent number: 5672446
    Abstract: Non-aqueous solid electrochemical cells with improved performance can be fabricated by employing intercalation based carbon anodes comprising a mixture of carbon particles having different morphologies and selected from platelet-type, microbead-type and/or fiber-type structures. The anodes exhibit good cohesion and adhesion characteristics. When employed in an electrochemical cell, the anode can attain a specific electrode capacity of at least 300 mAh/g. The electrochemical cell has a cycle life of greater than 1000 cycles, and has a first cycle capacity loss of only about 5-15%.
    Type: Grant
    Filed: January 29, 1996
    Date of Patent: September 30, 1997
    Assignee: Valence Technology, Inc.
    Inventors: Jeremy Barker, Jeffrey Swoyer, J. Lee Morris, Wade Guindy, Frederik Flemming
  • Patent number: 5670277
    Abstract: The invention provides a rechargeable lithium battery which comprises an electrolyte; a negative electrode having a compatible active material; and a positive electrode comprising a lithium copper oxide intercalation compound. The positive electrode active material is characterized by an ability to deintercalate lithium ions for intercalation into the negative electrode active material. The lithium copper oxide has a proportion of 2 lithium ions per formula unit of the copper oxide and upon electrochemical interaction with a negative electrode deintercalates lithium ions whereupon the proportion of lithium ions per copper oxide formula unit is less than 2. The lithium copper oxide is a compound represented by the nominal general formula Li.sub.2 CuO.sub.2. The lithium copper oxide compound is alternatively represented by the nominal general formula Li.sub.2-x CuO.sub.2, signifying its capability to deintercalate lithium.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: September 23, 1997
    Assignee: Valence Technology, Inc.
    Inventors: Jeremy Barker, M. Yazid Saidi
  • Patent number: 5670272
    Abstract: In order to maintain electrical contact between the anode, cathode and electrolyte layers in an electrochemical cell, a layer of material under tension is wrapped around the cell so that the material compresses the layers together to ensure sufficient electrical contact. Alternatively, a metal, foam or inflatable gas spring is employed in a housing structure containing the electrochemical cell to apply a compressive force to achieve the same result.
    Type: Grant
    Filed: March 31, 1994
    Date of Patent: September 23, 1997
    Assignee: Valence Technology, Inc.
    Inventors: S. Scot Cheu, Russell D. Moulton
  • Patent number: 5670273
    Abstract: A method of fabricating electrochemical cells and batteries wherein the successive anode and cathode layers are separated by a polymeric electrolyte layer having a protruding polymer edge around its perimeter which reduces the likelihood of inadvertent contact between the anode and cathode current collectors is provided. The polymer edge functions as a non-conducting physical barrier positioned between adjacent current collectors.
    Type: Grant
    Filed: February 22, 1996
    Date of Patent: September 23, 1997
    Assignee: Valence Technology, Inc.
    Inventors: David A. Velasquez, Douglas B. Holmes, E. Lawrence Goglin
  • Patent number: 5660948
    Abstract: Non-aqueous electrochemical cells with improved performance can be fabricated by employing anodes comprising a composition having graphite particles that have a BET method specific surface area of about 6 to about 12 m.sup.2 /g and a crystallite height L.sub.c of about 100 nm to about 120 nm, and wherein at least 90% (wt) of the graphite particles are less than 16 .mu.m in size; a cathode; and a non-aqueous electrolyte containing a solvent and salt that is interposed between the anode and cathode. When employed in an electrochemical cell, the anode can attain a specific electrode capacity of at least 300 mAhr/g. The electrochemical cell has a cycle life of greater than 1500 cycles, and has a first cycle capacity loss of only about 10% to about 15%.
    Type: Grant
    Filed: September 26, 1995
    Date of Patent: August 26, 1997
    Assignee: Valence Technology, Inc.
    Inventor: Jeremy Barker
  • Patent number: 5656394
    Abstract: There is provided an electrochemical cell which has a non-metal negative electrode (anode on discharge). The anode is not a solid metal, is not metallic, and has no free metal. Rather, an amount of lithium ions are incorporated into the anode carbon-polymer structure. The anode of the invention has no more than a minor amount of lithium in a precharged or fully discharged state. The anode is used with lithium-containing cathodes (positive electrodes), preferably of the intercalation type. The anode of the invention is of a material which includes carbon, an electrolyte, and one or more constituents selected from the group consisting of metal and semi-metal elements and compounds and alloys thereof, other than lithium and its alloys. Such constituents are further characterized by an ability to react electrochemically with lithium by accepting and releasing lithium. Preferred metals and semi-metals include aluminum, boron and silicon, and compounds and alloys thereof, such as AlSi.
    Type: Grant
    Filed: August 9, 1994
    Date of Patent: August 12, 1997
    Assignee: Valence Technology, Inc.
    Inventors: Rene Koksbang, Pia Tonder
  • Patent number: 5656326
    Abstract: In a method for coating a shear-thinning cathode material having a high viscosity on a substrate, the substrate is drawn through a nip defined by a rotating backing roller and a notched bar disposed at a distance from the backing roller. The notched bar is convexly curved in shape in a region prior to the nip and is formed with a notch extending in from the curved region of the notched bar at the nip. The cathode material is supplied onto a first surface of the substrate, the first surface facing the notched bar. At least a portion of the first surface of the substrate is coated with a uniform thickness layer of the cathode material by applying steadily increasing shear forces to the supplied cathode material as the cathode material on the substrate is drawn into the nip and contacts the curved region of the notched bar. The cathode material layer is removed from contact with the notched bar by drawing the cathode material layer coated on the substrate past the notch in the notched bar.
    Type: Grant
    Filed: August 24, 1995
    Date of Patent: August 12, 1997
    Assignee: Valence Technology, Inc.
    Inventor: Steven M. Mallinson