System and Method For Measuring Fuel Cell Voltage

• US 20080191702A1
• Filed: 11/29/2005
• Published: 08/14/2008
• Est. Priority Date: 11/30/2004
• Status: Active Grant

• Current Assignee: Vlaamse Instelling Voor Technologisch Onderzoek, Vlaamse Instelling Voor Technologisch Onderzoek Nv (Vito Nv)
• Original Assignee: Vlaamse Instelling Voor Technologisch Onderzoek (V
• Inventors: Coenen, Peter
• Granted Patent: US 8,030,941 B2
• Time in Patent Office: Days
• US Class Current: 324/434
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A system for measuring individual cell voltages of a fuel cell stack includes a plurality of voltage scanning units (VSU). Each VSU is arranged for being connected to a group of cells, belonging to the fuel cell stack, the group of cells being provided with terminals that allow measuring a cell voltage. Each VSU comprises a filter/regulator that provides a voltage reference signal V_ref, that is applied to a first terminal of a first cell of the group of cells. The VSU further includes a multiplexer arranged for consecutively connecting the other terminals of the group of cells to a first input of an A/D converter, whereby the A/D converter is further provided with a second input for receiving the voltage reference signal V_ref. The ADC is further arranged for being fed with a supply voltage V_sup+ and for A/D converting a signal derived from the signals at the first and second input.

Claims

1. A system for measuring individual cell voltages of a fuel cell stack, said system comprising a plurality of voltage scanning units (VSU), each VSU arranged for being connected to a group of cells, belonging to said fuel cell stack, said group of cells being provided with terminals providing for measuring a cell voltage,

wherein each VSU comprises a filter/regulator providing a voltage reference signal, said voltage reference signal being applied to a first terminal of a first cell of said group of cells, said VSU further comprising a multiplexer arranged for consecutively connecting the other terminals of said group of cells to a first input of an analog to digital converter, said analog to digital converter further being provided with a second input for receiving said voltage reference signal, said analog to digital converter further arranged for being fed with a supply voltage and for analog to digital converting a signal derived from said signals at said first and said second input

2. The system for measuring individual cell voltages as recited in claim 1, wherein said voltage reference signal is smaller than said supply voltage.

3. The system for measuring individual cell voltages as recited in claim 1, further comprising a main controller being connected to at least one VSU of said plurality of VSUs.

4. The system for measuring individual cell voltages as recited in claim 1, wherein each VSU comprises a protocol driver, said protocol driver comprising a unique identification for said VSU.

5. The system for measuring individual cell voltages as recited in claim 1, wherein said protocol driver is arranged for communicating with said main controller.

6. The system for measuring individual cell voltages as in claim 1, wherein said supply voltage V_sup+ is drawn from an alternating current power bus, connected via capacitive coupling to said filter/regulator.

7. The system for measuring individual cell voltages as claim 1, wherein said VSU further comprises optocouplers.

8. A method for measuring individual cell voltages of a group of cells belonging to a fuel cell stack, said group of cells being provided with terminals, said method comprising the steps of:

connecting a voltage scanning unit (VSU) to said group of cells,

providing a voltage reference signal to a first terminal of a first cell of said group of cells,

applying said voltage reference signal to a first input of an analog to digital converter, said analog to digital converter being comprised in said VSU and being fed by a supply voltage,

connecting consecutively a voltage signal from the other terminals of said group of cells to be measured to a second input of said analog to digital converter, said analog to digital converter thereby converting a signal derived from said signals at said first and said second input.

9. A method for measuring individual cell voltages as recited in claim 8, further comprising the steps of, in case a measured cell voltage signal exceeds a predetermined threshold, calculating the minimum, average and maximum voltage of said fuel cell stack and perform a correcting action based on said minimum, average and maximum voltage.