# US 2025/0096291 A1 · Method and Device of Controlling Drain Valve in Fuel Cell, Controller, Fuel Cell System, and Medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0096291 A1 - Document ID: US20250096291A1 - Status: Published application - Kind: A1 - Application number: 18/827,998 - Filed: 2024-09-09 - Published: 2025-03-20 - Earliest claimed: 2023-09-19 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Ren Dong; Wei Chen; Bo Wei; Yiming Song - Web page: https://patentgrep.com/patent/US20250096291A1 ## CPC - H01M 8/04761: {of fuel cell exhausts} - H01M 8/04097: {with recycling of the reactants (H01M8/04119, H01M8/04104 take precedence)} - H01M 8/04164: {by condensers, gas-liquid separators or filters} - H01M 8/04425: {at auxiliary devices, e.g. reformers, compressors, burners} - H01M 8/04567: {of auxiliary devices, e.g. batteries, capacitors} - H01M 8/04589: {of fuel cell stacks} - H01M 8/04597: {of auxiliary devices, e.g. batteries, capacitors} - H01M 8/04828: Humidity; Water content - H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane - Y02E 60/50: 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 ## Abstract A method and device of controlling a drain valve of a fuel cell, a controller, a fuel cell system, and a medium is disclosed. The method includes (i) acquiring a permeate water mass flow rate from a cathode to an anode of the fuel cell system and a separation efficiency of a water-gas separator in the fuel cell system, (ii) determining a water mass flow rate level of water passing through a hydrogen circulating pump based on a drive current of the hydrogen circulating pump in the fuel cell system, (iii) determining a circulating water mass flow rate passing through the hydrogen circulating pump based on the permeate water mass flow rate, the separation efficiency, and the water mass flow rate level, and (iv) controlling the drain valve in the fuel cell system based on the circulating water mass flow rate. Solutions provided by the examples of the present disclosure are capable of more precisely controlling a frequency and duration of opening the drain valve while saving costs, thereby being capable of improving the safety and performance of the fuel cell system. ## Claims ### Claim 1 A method of controlling a drain valve in a fuel cell system, comprising: acquiring a permeate water mass flow rate from a cathode to an anode of the fuel cell system and a separation efficiency of a water-gas separator in the fuel cell system; determining a water mass flow rate level of water passing through a hydrogen circulating pump based on a drive current of the hydrogen circulating pump in the fuel cell system; determining a circulating water mass flow rate passing through the hydrogen circulating pump based on the permeate water mass flow rate, the separation efficiency, and the water mass flow rate level; and controlling the drain valve in the fuel cell system based on the circulating water mass flow rate. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the water mass flow rate level of water passing through the hydrogen circulating pump comprises: determining values indicative of an upward offset and an oscillation of the drive current based on the drive current, drive voltage, reference voltage, rotating speed of the hydrogen circulating pump and a current of a galvanic pile; and determining the water mass flow rate level of the water passing through the hydrogen circulating pump based on the values indicative of the upward offset and the oscillation of the drive current. ### Claim 3 (depends on 2) The method of claim 2, wherein determining the values indicative of the upward offset and the oscillation of the drive current comprises: determining a reference value associated with the drive current based on the rotating speed of the hydrogen circulating pump and the current of the galvanic pile; and determining the values indicative of the upward offset and the oscillation of the drive current based on the drive current and the reference value. ### Claim 4 (depends on 1) The method of claim 1, wherein determining the circulating water mass flow rate passing through the hydrogen circulating pump comprises: acquiring a historical circulating water mass flow rate passing through the hydrogen circulating pump at a first moment; determining a first water mass flow rate based on the permeate water mass flow rate and the historical circulating water mass flow rate; and determining the circulating water mass flow rate based on the first water mass flow rate, the separation efficiency, and the water mass flow rate level. ### Claim 5 (depends on 4) The method of claim 4, wherein determining the circulating water mass flow rate comprises: determining a circulating water mass flow rate to be corrected based on the first water mass flow rate and the separation efficiency; and determining the circulating water mass flow rate based on the circulating water mass flow rate to be corrected and the water mass flow rate level. ### Claim 6 (depends on 5) The method of claim 5, wherein determining the circulating water mass flow rate comprises: acquiring a mapping relationship between a plurality of water mass flow rate levels and a plurality of correction parameters; determining a correction parameter corresponding to the water mass flow rate level in the plurality of correction parameters based on the water mass flow rate level and the mapping relationship; and determining the circulating water mass flow rate based on the circulating water mass flow rate to be corrected and the correction parameter. ### Claim 7 (depends on 1) The method of claim 1, wherein the permeate water mass flow rate is a first permeate water mass flow rate, the separation efficiency is a first separation efficiency, and controlling the drain valve in the fuel cell system further comprises: acquiring a second permeate water mass flow rate from the cathode to the anode of the fuel cell system and a second separation efficiency of the water-gas separator at a second moment; and determining a separated water mass flow rate separated by the water-gas separator based on the circulating water mass flow rate, the second permeate water mass flow rate and the second separation efficiency; and controlling the drain valve in the fuel cell system based on the separated water mass flow rate. ### Claim 8 (depends on 7) The method of claim 7, wherein determining the separated water mass flow rate separated by the water-gas separator comprises: determining a second water mass flow rate based on the second permeate water mass flow rate and the circulating water mass flow rate; and determining the separated water mass flow rate based on the second water mass flow rate and the second separation efficiency. ### Claim 9 (depends on 8) The method of claim 8, wherein determining the separated water mass flow rate further comprises: determining a condensed water mass flow rate in a galvanic pile flow channel of the fuel cell system; and determining the separated water mass flow rate based on the second water mass flow rate and the condensed water mass flow rate. ### Claim 10 (depends on 1) The method of claim 1, wherein controlling the drain valve in the fuel cell system comprises: determining an amount of water separated by the water-gas separator within a period of time based on the separated water mass flow rate separated by the water-gas separator; and determining at least one of a frequency and duration of opening the drain valve based on the amount of water. ### Claim 11 A device of controlling a drain valve in a fuel cell system, comprising: a permeate water flow rate acquiring unit configured to acquire a permeate water mass flow rate from a cathode to an anode of the fuel cell system and a separation efficiency of a water-gas separator in the fuel cell system; a circulating water level determining unit configured to determine a water mass flow rate level of water passing through a hydrogen circulating pump based on a drive current of the hydrogen circulating pump in the fuel cell system; a circulating water flow rate determining unit configured to determine a circulating water mass flow rate passing through the hydrogen circulating pump based on the permeate water mass flow rate, the separation efficiency, and the water mass flow rate level; and a drain valve control unit configured to control the drain valve in the fuel cell system based on the circulating water mass flow rate. ### Claim 12 (depends on 1) A controller, comprising: at least one processor; and a memory coupled to the at least one processor and having instructions stored thereon, the instructions, when executed by the at least one controller, causing the controller to perform the method according to claim 1. ### Claim 13 (depends on 12) A fuel cell system, comprising: a galvanic pile; a water-gas separator located in a first channel connected to an anode outlet of the galvanic pile; a drain valve located in a second channel connected to the water-gas separator; a hydrogen circulating pump located in a third channel connected to an anode inlet of the galvanic pile; and a controller according to claim 12. ### Claim 14 (depends on 1) A computer-readable storage medium having computer-executable instructions stored thereon, wherein the computer-executable instructions are executed by the processor to implement the method according to claim 1.