Ramkumar Krishnan

US Patent:

7776386, Aug 17, 2010

Filed:

Jan 31, 2007

Appl. No.:

11/669712

Inventors:

Chowdary R. Koripella - Scottsdale AZ, US
Kurt W. Eisenbeiser - Tempe AZ, US
Ramkumar Krishnan - Gilbert AZ, US

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01M 4/88
H01M 8/02
H01M 8/10

US Classification:

427115

Abstract:

A method is provided for fabricating an integrated micro fuel cell that derives power from a three-dimensional fuel/oxidant interchange having increased surface area and that is positioned on a second substrate that may be either porous or flexible with gas access holes, thereby avoiding precise alignment requirements of the openings providing fuel thereto. The method comprises forming on a first substrate, a plurality of pedestals including an anode and a cathode each comprising a porous metal; positioning an electrolyte between the anode and the cathode; and forming first metal contacts on the anode and cathode. The first substrate is removed and a second substrate is positioned against the fuel cell wherein the first metal contacts are selectively positioned to make electrical contact with second metal contacts on the second substrate.

US Patent:

8492052, Jul 23, 2013

Filed:

Oct 8, 2010

Appl. No.:

12/901410

Inventors:

Cody A Friesen - Fort McDowell AZ, US
Ramkumar Krishnan - Gilbert AZ, US
Grant Friesen - Fountain Hills AZ, US

Assignee:

Fluidic, Inc. - Scottsdale AZ

International Classification:

H01M 8/04

US Classification:

429512, 429498, 429499, 429503

Abstract:

An electrochemical cell includes a fuel electrode configured to operate as an anode to oxidize a fuel when connected to a load. An electrode holder includes a cavity for holding the fuel electrode, at least one inlet connected to the cavity on one side of the cavity and configured to supply an ionically conductive medium to the cavity, and at least one outlet connected to the cavity on an opposite side of the cavity and configured to allow the ionically conductive medium to flow out of the cavity. A plurality of spacers extend across the fuel electrode and the cavity in a spaced relation from each other to define a plurality of flow lanes in the cavity.

US Patent:

8632921, Jan 21, 2014

Filed:

Feb 2, 2011

Appl. No.:

13/019923

Inventors:

Cody A. Friesen - Fort McDowell AZ, US
Grant Friesen - Fountain Hills AZ, US
Ramkumar Krishnan - Gilbert AZ, US
Todd Trimble - Phoenix AZ, US

Assignee:

Fluidic, Inc. - Scottsdale AZ

International Classification:

H01M 8/22
H01M 8/06
H01M 8/08
H01M 8/04

US Classification:

429405, 429408, 429403, 429498, 429513, 429512

Abstract:

An electrochemical cell includes a first electrode configured to operate as an anode to oxidize a fuel when connected to a load. The first electrode includes a permeable electrode body configured to allow flow of an ionically conductive medium therethrough. An electrode holder includes a cavity for holding the first electrode. A diffuser is positioned in the cavity between the first electrode and the electrode holder with a gap formed between the diffuser and the electrode holder. The diffuser includes openings configured to allow flow of the ionically conductive medium therethrough and to distribute the flow through the first electrode. A second electrode is positioned in the cavity on a side of the first electrode that is opposite the diffuser, and is configured to operate as a cathode when connected to the load and in contact with the ionically conductive medium.

US Patent:

20080003485, Jan 3, 2008

Filed:

Jun 30, 2006

Appl. No.:

11/479737

Inventors:

Ramkumar Krishnan - Gilbert AZ, US
William J. Dauksher - Mesa AZ, US
Chowdary R. Koripella - Scottsdale AZ, US

International Classification:

H01M 4/86
H01M 8/10
B05D 5/12
H01M 4/88

US Classification:

429 44, 427115, 502101, 429 30

Abstract:

A method is provided for patterning a solid proton conducting electrolyte () for a micro fuel cell. The method comprises patterning a first side () of a solid proton conducting electrolyte () to increase the surface area, coating the patterned first side () with an electrocatalyst (), providing a first electrical conductor () to the first side (), and providing a second electrical conductor () to a second side () of the solid proton conducting electrolyte () opposed to the first side (). One exemplary embodiment comprises depositing a solid proton conducting electrolyte () over a substrate (), patterning the solid proton conducting electrolyte () to form a plurality of pedestals (), each pedestal () having an anode side adjacent a anode region () and a cathode side adjacent a cathode region (), coating the anode () and cathode () sides with an electrocatalyst (), providing a first electrical conductor () to the anode side (); and providing a second electrical conductor () to the cathode side ().

US Patent:

20080061027, Mar 13, 2008

Filed:

Sep 12, 2006

Appl. No.:

11/519553

Inventors:

Pawitter S. Mangat - Gilbert AZ, US
John J. D'Urso - Chandler AZ, US
Chowdary R. Koripella - Scottsdale AZ, US
Ramkumar Krishnan - Gilbert AZ, US

International Classification:

H01B 13/00
B05D 5/12
H01M 8/02

US Classification:

216 17, 427115, 429 38

Abstract:

A method is provided for fabricating a fuel cell that requires only front side alignment techniques to fabricate gas access holes. The method comprises etching the front side of a substrate () to provide a channel (), and forming a pedestal () on the front side of the substrate, wherein the pedestal () comprises an anode side () defining a fuel region () aligned with the channel (). An electrolyte () is positioned between the anode side () and a cathode side (), and the fuel region () is capped with an insulator (). A portion of the substrate () is removed from a back side to expose the channel ().

US Patent:

20080182012, Jul 31, 2008

Filed:

Jan 31, 2007

Appl. No.:

11/669720

Inventors:

Allison M. Fisher - Chandler AZ, US
Ramkumar Krishnan - Gilbert AZ, US
Kajal Parekh - Phoenix AZ, US

Assignee:

MOTOROLA, INC. - Schaumburg IL

International Classification:

B05D 5/12

US Classification:

427115, 427 58

Abstract:

A method is provided for fabricating a hybrid gas diffusion layer/current collector/electrocatalyst structure () suitable for 3D microfuel cell devices (). The method comprises forming a macroporous electrically conductive structure () on a substrate () positioned such that a plurality of cathode current collector/GDL () and anode current collector/GDL () are formed. An electrocatalyst material () is deposited in contact with these structures, completing the formation of cathode () and anode () hybrid current collector/GDL/electrocatalyst structures. When electrolyte () is positioned between the electrocatalyst material () contacting the cathode collector () and the electrocatalyst material () contacting each of the plurality of anode collectors (), the resulting MEA is suitable for use in a micro fuel cell device.

US Patent:

20090217963, Sep 3, 2009

Filed:

Feb 29, 2008

Appl. No.:

12/040259

Inventors:

Yong Liang - Gilbert AZ, US
Kurt W. Eisenbeiser - Tempe AZ, US
Allison M. Fisher - Chandler AZ, US
Ramkumar Krishnan - Gilbert AZ, US

Assignee:

MOTOROLA, INC. - Schaumburg IL

International Classification:

H01L 31/18
H01L 31/0224

US Classification:

136243, 438 85, 427 74, 257E31126

Abstract:

A method of making a plurality of photovoltaic cells () for charging a battery () of an electronic device () includes forming by a self-assembly process a plurality of interdigitated photovoltaic cells () between two terminal electrodes () coupled to the battery (). One electrode is a transport conductive material () including a conductive material () having sidewalls () defining a plurality of pores (). A conductive electrode material () is formed over an electrolyte () which is formed over a sensitizing material () which is formed over an active transport material () on the sidewalls ().

US Patent:

20100316935, Dec 16, 2010

Filed:

Dec 4, 2009

Appl. No.:

12/631484

Inventors:

Cody A. Friesen - Mesa AZ, US
Joel R. Hayes - Chandler AZ, US
Ramkumar Krishnan - Gilbert AZ, US
Todd Trimble - Scottsdale AZ, US

Assignee:

Fluidic, LLC - Scottsdale AZ

International Classification:

H01M 8/02

US Classification:

429512

Abstract:

An electrochemical cell system for generating electrical power is disclosed. The electrochemical cell system comprises a plurality of fluidly connected electrochemical cells. Each electrochemical cell comprises an anode and a cathode. The anode is configured to permit a fluid comprising at least an electrolyte to flow in contact therewith to oxidize a fuel. The cathode is permeable to an oxidizer and is configured to receive electrons to reduce the oxidizer. The cathode and the anode are spaced apart to define a gap therebetween for receiving the fluid flow. The plurality of electrochemical cells are connected in fluid flow series such that, for each pair of fluidly connected electrochemical cells, the fluid flows from a first cell of the pair of cells to a second cell of the pair of cells. The plurality of electrochemical cells are connected electrically in series such that, for each pair of fluidly connected electrochemical cells, the cathode of the first cell of the pair is electrically connected to the anode of the second cell of the pair.