# US 10,122,037 B2 · Method for controlling an operating point change of a fuel cell stack and a fuel cell system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,122,037 B2 - Document ID: US10122037B2 - Status: Granted - Kind: B2 - Application number: 15/090,340 - Filed: 2016-04-04 - Published: 2016-10-27 - Granted: 2018-11-06 - Earliest claimed: 2015-04-24 - Assignees: Volkswagen Aktiengesellschaft - Applicants: Volkswagen AG - Inventors: Maren Ramona Kirchhoff; Sebastian Kirsch; Patrick Zihrul; Ingmar Hartung - Web page: https://patentgrep.com/patent/US10122037B2 ## CPC - H01M 8/0494: {of fuel cell stacks} - H01M 8/04753: {of fuel cell reactants} - H01M 8/0488: {of fuel cell stacks} - H01M 8/0491: {of fuel cell stacks} - H01M 8/04111: using a compressor turbine assembly - H01M 8/04141: {by water containing exhaust gases} - H01M 8/04149: {by diffusion, e.g. making use of membranes} - H01M 16/006: {of fuel cells with rechargeable batteries} - H01M 2008/1095: {Fuel cells with polymeric electrolytes} - H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane - Y02E 60/10: Energy storage using batteries - Y02E 60/50: Fuel cells - Y02T 90/40: Application of hydrogen technology to transportation, e.g. using fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method for controlling an operating point change of a fuel cell stack (10) operated with an anode operating medium and with a cathode operating medium, in which the fuel cell stack (10) is controlled in such a way that, starting from an initial electric power (L1), the fuel cell stack generates a target power (L2) requested by an electrical consumer (51), which is greater than the initial power (L1) is provided. It is provided that the electric power generated by the fuel cell stack (10) is controlled in accordance with a predetermined current-voltage profile (S1, S2, S3), so that a voltage present at the fuel cell stack (10), starting from an initial voltage (U1) corresponding to the initial power (L1), passes through a local voltage minimum (Umin) and then increases to an end voltage corresponding to the target power (L2). ## Claims ### Claim 1 A method for controlling an operating point change of a fuel cell stack operated with an anode operating medium and with a cathode operating medium, the method comprising: controlling the fuel cell stack in such a way that, starting from an electric initial power, the fuel cell stack generates a target power requested by an electrical consumer, the target power being greater than the initial power, the electric power generated by the fuel cell stack being controlled in accordance with a predetermined current-voltage profile, so that a voltage present at the fuel cell stack, starting from an initial voltage corresponding to the initial power, decreases to a local voltage minimum and then increases to an end voltage corresponding to the target power. ### Claim 2 (depends on 1) The method as recited in claim 1 wherein the local voltage minimum corresponds to a single cell voltage of no more than 0.7 volts. ### Claim 3 (depends on 2) The method as recited in claim 2 wherein the local voltage minimum corresponds to a single cell voltage of no more than 0.6 volts. ### Claim 4 (depends on 1) The method as recited in claim 1 wherein an electric power generated during the operating point change is directly consumed by an electrical consumer. ### Claim 5 (depends on 4) The method as recited in claim 4 wherein the electrical consumer is a traction motor. ### Claim 6 (depends on 1) The method as recited in claim 1 wherein the generated electric power is controlled by modifying a stoichiometry of the anode operating medium or of the cathode operating medium in accordance with the current-voltage profile. ### Claim 7 (depends on 6) The method as recited in claim 6 wherein the generated electric power is controlled by modifying the stoichiometry of the cathode operating medium in accordance with the current-voltage profile. ### Claim 8 (depends on 1) The method as recited in claim 1 wherein the generated electric power is controlled in accordance with the predetermined current-voltage profile passing through a current intensity or power higher than the target power, and further comprising storing a surplus power in an electric energy store. ### Claim 9 (depends on 1) The method as recited in claim 1 wherein the generated electric power is controlled in accordance with the predetermined current-voltage profile in such a way that initially the voltage decreases to a current intensity corresponding to the target power, after which the voltage increases at a constant current intensity until the voltage reaches a voltage corresponding to the target power. ### Claim 10 (depends on 1) The method as recited in claim 1 wherein the generated electric power is controlled in accordance with the predetermined current-voltage profile in such a way that initially the voltage is ramped down to the local voltage minimum, and then ramped up again, and the current intensity then increases until the current intensity reaches a current intensity corresponding to the target power. ### Claim 11 (depends on 10) The method as recited in claim 10 wherein the voltage is initially ramped down to 0 volts. ### Claim 12 (depends on 1) A fuel cell system comprising: a fuel cell stack, and a control unit configured to carry out executable steps to execute the method as recited in claim 1. ### Claim 13 (depends on 12) A vehicle comprising: a fuel cell system as recited in claim 12. ### Claim 14 (depends on 9) The method as recited in claim 9 wherein the voltage decrease to the current intensity corresponding to target power occurs by increasing the current without adapting the cathode operating medium. ### Claim 15 (depends on 14) The method as recited in claim 14 wherein a regeneration of catalytic material of a cathode occurs when the fuel cell stack is at the local voltage minimum. ### Claim 16 (depends on 9) The method as recited in claim 9 wherein the voltage increase occurring at the constant current intensity occurs by adapting a stoichiometry.