Water electrolysis system and water level error calculation apparatus

Patent metadata

Field	Value
Publication number	US-11629075-B2
Application number	US-202117174294-A
Country	US
Kind code	B2
Filing date	Feb 11, 2021
Priority date	Feb 21, 2020
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

A water electrolysis system includes: a water electrolyzer configured to electrolyze water to generate gas including oxygen and hydrogen; a gas-liquid separator configured to separate gas phase including hydrogen from liquid phase of the gas generated by the water electrolyzer; a water level detector configured to detect a water level in the gas-liquid separator; a pressure detector configured to detect a pressure of the gas phase in the gas-liquid separator; and a CPU and a memory coupled to the CPU. The CPU is configured to perform: calculating an error of the water level in the gas-liquid separator detected by the water level detector based on the pressure of the gas phase in the gas-liquid separator detected by the pressure detector.

First claim

What is claimed is:

1. A water electrolysis system, comprising:
a water electrolyzer configured to electrolyze water to generate gas including oxygen and hydrogen;
a gas-liquid separator configured to separate a gas phase including hydrogen from a liquid phase of the gas generated by the water electrolyzer;
a water level detector configured to detect a water level in the gas-liquid separator;
a pressure detector configured to detect a pressure of the gas phase in the gas-liquid separator; and
a CPU and a memory coupled to the CPU, wherein
the CPU is configured to perform:
calculating an error of the water level in the gas-liquid separator detected by the water level detector based on the pressure of the gas phase in the gas-liquid separator detected by the pressure detector;
calculating the pressure of the gas phase in the gas-liquid separator based on an amount of hydrogen generated by the water electrolyzer and the water level in the gas-liquid separator detected by the water level detector; and
calculating the error of the water level in the gas-liquid separator detected by the water level detector based on the pressure of the gas phase calculated and the pressure of the gas phase detected by the pressure detector.

2. The water electrolysis system according to claim 1 , further comprising:
a draining device configured to drain water in the gas-liquid separator, wherein
the CPU is configured to perform:
correcting the water level in the gas-liquid separator detected by the water level detector based on the error of the water level calculated; and
controlling the draining device based on the water level corrected.

3. The water electrolysis system according to claim 2 , wherein
the CPU is configured to perform:
controlling the draining device so as not to fill up nor empty out the gas-liquid separator.

4. The water electrolysis system according to claim 1 , wherein
the water level detector is a weight sensor configured to detect the water level in the gas-liquid separator based on a weight of the gas-liquid separator.

5. The water electrolysis system according to claim 4 , wherein
the gas-liquid separator includes a substantially cylindrical vessel, wherein
the water level detector is configured to detect the water level in the vessel, wherein
the pressure detector is configured to detect the pressure of the gas phase in the vessel, wherein
the water level detector is disposed in contact with a bottom of the vessel.

6. The water electrolysis system according to claim 1 , wherein
the gas-liquid separator is connected to a cathode side of the water electrolyzer and is connected to a back pressure valve set to a predetermined pressure, wherein
the pressure of the gas phase in the gas-liquid separator increases in accordance with an amount of hydrogen generated on the cathode side of the water electrolyzer up to the predetermined pressure.

7. The water electrolysis system according to claim 6 , wherein
the pressure detector is attached to a piping connecting the cathode side of the water electrolyzer and the gas-liquid separator.

8. A water electrolysis system, comprising:
a water electrolyzer configured to electrolyze water to generate gas including oxygen and hydrogen;
a gas-liquid separator configured to separate a gas phase including hydrogen from a liquid phase of the gas generated by the water electrolyzer;
a water level detector configured to detect a water level in the gas-liquid separator;
a pressure detector configured to detect a pressure of the gas phase in the gas-liquid separator; and
a CPU and a memory coupled to the CPU, wherein
the CPU is configured to function as:
an arithmetic unit configured to calculate an error of the water level in the gas-liquid separator detected by the water level detector based on the pressure of the gas phase in the gas-liquid separator detected by the pressure detector, to calculate the pressure of the gas phase in the gas-liquid separator based on an amount of hydrogen generated by the water electrolyzer and the water level in the gas-liquid separator detected by the water level detector, and to calculate the error of the water level in the gas-liquid separator detected by the water level detector based on the pressure of the gas phase calculated and the pressure of the gas phase detected by the pressure detector.

9. The water electrolysis system according to claim 8 , further comprising:
a draining device configured to drain water in the gas-liquid separator, wherein
the CPU is configured to function as:
a drainage control unit configured to correct the water level in the gas-liquid separator detected by the water level detector based on the error of the water level calculated by the arithmetic unit, and to control the draining device based on the water level corrected.

10. The water electrolysis system according to claim 9 , wherein
the drainage control unit is configured to control the draining device so as not to fill up nor empty out the gas-liquid separator.

11. The water electrolysis system according to claim 8 , wherein
the water level detector is a weight sensor configured to detect the water level in the gas-liquid separator based on a weight of the gas-liquid separator.

12. The water electrolysis system according to claim 11 , wherein
the gas-liquid separator includes a substantially cylindrical vessel, wherein
the water level detector is configured to detect the water level in the vessel, wherein
the pressure detector is configured to detect the pressure of the gas phase in the vessel, wherein
the water level detector is disposed in contact with a bottom of the vessel.

13. The water electrolysis system according to claim 8 , wherein
the gas-liquid separator is connected to a cathode side of the water electrolyzer and is connected to a back pressure valve set to a predetermined pressure, wherein
the pressure of the gas phase in the gas-liquid separator increases in accordance with an amount of hydrogen generated on the cathode side of the water electrolyzer up to the predetermined pressure.

14. The water electrolysis system according to claim 13 , wherein
the pressure detector is attached to a piping connecting the cathode side of the water electrolyzer and the gas-liquid separator.

Assignees

• Honda Motor Co Ltd

Inventors

• Asano Yuji
• Takeuchi Jun
• Aoki Kazuya

Classifications

• C25B9/77

  having diaphragms · CPC title

• C25B9/05

  Pressure cells · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title

• C02F1/46109 Primary

  Electrodes · CPC title

• C02F2201/4612

  Controlling or monitoring · CPC title