Water electrolysis system and its control method
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HONDA MOTOR CO LTD
- Filing Date
- 2024-11-28
- Publication Date
- 2026-06-09
Smart Images
Figure 2026093716000001_ABST
Abstract
Claims
1. A water electrolysis stack having a membrane electrode structure for water electrolysis in which an electrolyte membrane is sandwiched between an anode electrode and a cathode electrode, and which generates hydrogen gas and oxygen gas from supplied water, A water electrolysis power supply device that supplies water electrolysis current between the anode electrode and the cathode electrode of the water electrolysis membrane electrode structure, A hydrogen boost stack having a membrane electrode structure for hydrogen boosting in which an electrolyte membrane is sandwiched between an anode electrode and a cathode electrode, and which boosts the hydrogen gas generated by the water electrolysis stack, A hydrogen boost power supply device that supplies a hydrogen boost current between the anode electrode and the cathode electrode of the hydrogen boost membrane electrode structure, A control device for controlling the water electrolysis power supply and the hydrogen boost power supply, A water electrolysis system having, The control device is When the water electrolysis system is started, the water electrolysis power supply and the hydrogen boosting power supply are controlled so that the water electrolysis current and the hydrogen boosting current gradually increase. When the water electrolysis current and the hydrogen boost current are gradually increasing, the system detects whether flooding is occurring in the hydrogen boost stack, and when flooding is detected, it controls the system to pause the increase of the water electrolysis current and the hydrogen boost current and maintain them at a constant current value. Water electrolysis system.
2. In the water electrolysis system according to claim 1, The control device is Whether or not flooding is occurring in the hydrogen boost stack is detected by checking whether the cell voltage of the hydrogen boost stack has increased to a first threshold voltage. Water electrolysis system.
3. In the water electrolysis system according to claim 1, The control device is During control that pauses the increase of the water electrolysis current and the hydrogen boost current and maintains the constant current value, when it is detected that the flooding has been resolved, the water electrolysis power supply and the hydrogen boost power supply are controlled so that the water electrolysis current and the hydrogen boost current gradually increase in a stepwise manner from the current maintained at the constant current value. Water electrolysis system.
4. In the water electrolysis system according to claim 3, The control device is Whether or not the flooding in the hydrogen boost stack has been resolved is detected by whether or not the voltage between the electrodes of the hydrogen boost stack has dropped to a second threshold voltage. Water electrolysis system.
5. In the water electrolysis system according to claim 3, The control device is When the water electrolysis current and the hydrogen boosting current are gradually increased in the stepwise manner, when the water electrolysis current and the hydrogen boosting current reach the target current value, the water electrolysis current and the hydrogen boosting current are controlled so that the pressure of the hydrogen gas supplied from the water electrolysis stack to the hydrogen boosting stack becomes constant. Water electrolysis system.
6. In the water electrolysis system according to claim 1, A gas-liquid separator is provided between the water electrolysis stack and the hydrogen booster stack, and a hydrogen circulation pump is provided between the gas-liquid separator and the hydrogen booster stack. The control device, upon startup, drives the hydrogen circulation pump to circulate the hydrogen gas to the anode electrode of the hydrogen boost stack, thereby eliminating the flooding of the anode electrode. Water electrolysis system.
7. A control method for a water electrolysis system comprising: a water electrolysis stack having a membrane electrode structure for water electrolysis in which an electrolyte membrane is sandwiched between an anode electrode and a cathode electrode, and generating hydrogen gas and oxygen gas from supplied water; a water electrolysis power supply device that supplies water electrolysis current between the anode electrode and the cathode electrode of the water electrolysis membrane electrode structure; a hydrogen boost stack having a membrane electrode structure for hydrogen boosting in which an electrolyte membrane is sandwiched between an anode electrode and a cathode electrode, and boosting the hydrogen gas generated by the water electrolysis stack; a hydrogen boost power supply device that supplies hydrogen boosting current between the anode electrode and the cathode electrode of the hydrogen boost membrane electrode structure; and a control device that controls the water electrolysis power supply device and the hydrogen boost power supply device, wherein The steps include controlling the water electrolysis power supply and the hydrogen boosting power supply so that the water electrolysis current and the hydrogen boosting current gradually increase when the water electrolysis system is started, The steps include detecting whether flooding is occurring in the hydrogen boost stack when the water electrolysis current and the hydrogen boost current are gradually increasing, The procedure includes the step of, when the occurrence of the flooding is detected, pausing the increase in the water electrolysis current and the hydrogen boosting current and maintaining them at a constant current value. A method for controlling a water electrolysis system.