JP2012142145A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system achieving a high level of safety by controlling the pressure of hydrogen gas within an appropriate range with simple constitution.SOLUTION: The fuel cell system comprises: a hydrogen generating unit 4 containing a hydrogen generating material which generates hydrogen by an exothermic reaction with water, and generating hydrogen by the reaction between the hydrogen generating material and water; a water supply unit 2 supplying the hydrogen generating unit 4 with water; a fuel cell 6 generating power using the hydrogen generated by the hydrogen generating unit 4 as fuel; a hydrogen gas pressure measuring unit 5 measuring the pressure of hydrogen gas supplied from the hydrogen generating unit 4 to the fuel cell 6; a setting unit 8 setting the output voltage or the output current of the fuel cell 6; and a controlling unit 9 controlling the setting unit 8 so that the pressure of the hydrogen gas measured by the hydrogen gas pressure measuring unit 5 is within an appropriate range.

Description

  The present invention relates to a fuel cell system, and more particularly, to a small and highly portable fuel cell system.

  The polymer electrolyte fuel cell (PEFC) operates at low temperatures from room temperature to 100 ° C or less, and has features such as quick start / stop and high power density. It is expected to be used as a power generator for mobile devices such as cogeneration and automobiles, and as a portable power source.

  In general, a polymer electrolyte fuel cell is a porous polymer cell comprising a hydrogen ion conductive polymer electrolyte membrane as an electrolyte layer, a catalyst layer disposed on both sides thereof, and a gas diffusion layer disposed on both sides thereof. Electrode / electrolyte integrated body (MEA) composed of a high quality electrode base material.

  Hydrogen, ethanol, and the like have been proposed as fuels for use in solid polymer fuel cells, and various developments have been made. However, a solid polymer fuel cell using hydrogen as a fuel in terms of enabling high energy density. Is expected.

  As a method for producing hydrogen used as a fuel for a polymer electrolyte fuel cell, for example, Patent Document 1 contains at least one metal material selected from the group consisting of aluminum, magnesium, and alloys thereof. A method of producing hydrogen gas by reacting a hydrogen generating material that generates hydrogen by reaction with water with water is disclosed.

  By the way, when supplying hydrogen gas to the fuel cell, it is desirable to keep the pressure of the hydrogen gas within a certain range. If the pressure of hydrogen gas is too high, there is a risk that the container or piping will burst. On the other hand, if the pressure of the hydrogen gas is too low, the fuel required for power generation by the fuel cell is insufficient, so that the fuel cell deteriorates due to the voltage drop of the fuel cell or the output power of the fuel cell is insufficient.

  As a control method for keeping the pressure of hydrogen gas within a certain range, for example, Patent Document 2 includes a hydrogen storage buffer and a regulator between the hydrogen gas generator and the fuel cell, and the amount of water supplied to the container. A fuel cell system in which the pressure of hydrogen gas is kept within a certain range by controlling the amount of hydrogen gas generated by controlling the above is proposed.

Japanese Patent No. 4104041 JP 2005-347181 A

  However, in the method proposed in Patent Document 1, it takes time until the amount of hydrogen gas generated changes after the amount of water supply is changed, during which time the pressure of the hydrogen gas deviates from the desired range. There is a problem. Further, the method proposed in Patent Document 2 has a problem that it is difficult to reduce the size of the entire system because a device for adjusting the pressure is separately required.

  The present invention has been made to solve the above problems, and provides a fuel cell system capable of improving safety by controlling the pressure of hydrogen gas within an appropriate range with a simple configuration.

  In order to solve the above problems, a fuel cell system of the present invention contains a hydrogen generating material that generates hydrogen by an exothermic reaction with water, and generates hydrogen by reacting the hydrogen generating material with water to generate hydrogen. A water supply unit that supplies water to the hydrogen generation unit, a fuel cell that generates power using hydrogen generated in the hydrogen generation unit as fuel, and a pressure of hydrogen gas supplied from the hydrogen generation unit to the fuel cell The hydrogen gas pressure detection unit for detecting the pressure, the setting unit for setting the output voltage or output current of the fuel cell, and the setting so that the hydrogen gas pressure detected by the hydrogen gas pressure detection unit is within an appropriate range. And a control unit for controlling the unit.

  According to the present invention, it is possible to provide a fuel cell system capable of improving safety by controlling the pressure of hydrogen gas within an appropriate range with a simple configuration.

1 is a schematic configuration diagram showing a fuel cell system according to Embodiment 1 of the present invention. It is a flowchart figure for demonstrating operation | movement of the fuel cell system which concerns on Embodiment 1 of this invention. It is a graph which shows an example of operation | movement of the fuel cell system which concerns on Embodiment 1 of this invention. It is a graph which shows the other example of operation | movement of the fuel cell system which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the fuel cell system which concerns on Embodiment 2 of this invention. It is a flowchart figure for demonstrating operation | movement of the fuel cell system which concerns on Embodiment 2 of this invention. It is a graph which shows an example of operation | movement of the fuel cell system which concerns on Embodiment 2 of this invention. It is a graph which shows the other example of operation | movement of the fuel cell system which concerns on Embodiment 2 of this invention.

  A fuel cell system according to the present invention includes a hydrogen generating material that generates hydrogen by an exothermic reaction with water, a hydrogen generating unit that generates hydrogen by reacting the hydrogen generating material with water, and water in the hydrogen generating unit. A water supply unit that supplies hydrogen, a fuel cell that generates power using hydrogen generated in the hydrogen generation unit as a fuel, and a hydrogen gas pressure detection unit that detects the pressure of hydrogen gas supplied from the hydrogen generation unit to the fuel cell A setting unit that sets the output voltage or output current of the fuel cell, and a control unit that controls the setting unit so that the hydrogen gas pressure detected by the hydrogen gas pressure detection unit falls within an appropriate range. It is characterized by having. Thereby, the pressure of hydrogen gas can be controlled within an appropriate range with a simple configuration, and safety can be improved. Moreover, since a hydrogen storage buffer and a regulator are not required as in the prior art, the entire fuel cell system can be reduced in size.

  When the lower limit value of the appropriate range of the pressure of the hydrogen gas is a first threshold value and the upper limit value of the appropriate range is a second threshold value, the control unit is configured such that the hydrogen gas pressure is greater than the first threshold value. When the pressure is low, the setting unit is controlled to increase the output voltage of the fuel cell or to decrease the output current of the fuel cell. When the hydrogen gas pressure is higher than the second threshold value, the output voltage of the fuel cell The setting unit is controlled so as to decrease the output current or increase the output current of the fuel cell. Thereby, when the pressure of hydrogen gas is high, the consumption amount of hydrogen gas can be increased and the pressure of hydrogen gas can be lowered, and dangers such as rupture of containers and piping can be avoided. On the other hand, when the pressure of hydrogen gas is low, the consumption of hydrogen gas can be reduced to increase the pressure of hydrogen gas, the deterioration of the fuel cell due to the voltage drop of the fuel cell can be suppressed, and the output power of the fuel cell is insufficient Can be eliminated.

  The control unit may control the water supply unit when the hydrogen gas pressure is outside the proper range for a certain period of time after the setting unit is controlled. In this case, even if the output voltage or output current of the fuel cell is controlled, when the hydrogen gas pressure is outside the proper range for a certain period of time, the hydrogen gas pressure is adjusted within the proper range by adjusting the hydrogen generation amount. It can be accommodated in, and safety can be further enhanced. Specifically, after the control of the setting unit, the water supply unit is controlled to increase the amount of water supplied to the hydrogen generation unit when the hydrogen gas pressure is lower than the first threshold value for a certain period of time. Then, after the control of the setting unit, when the state in which the pressure of the hydrogen gas is higher than the second threshold value continues for a certain period of time, the water supply unit is controlled to reduce the amount of water supplied to the hydrogen generation unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

(Embodiment 1)
In the first embodiment, an example of the fuel cell system of the present invention will be described. FIG. 1 is a schematic configuration diagram showing a fuel cell system of the present embodiment.

  As shown in FIG. 1, the fuel cell system of the present embodiment includes a water container 1, a pump 2 as a water supply unit, a pump control unit 3, a hydrogen generation unit 4, and a hydrogen gas pressure detection unit 5. The fuel cell 6, the air inflow unit 7, the setting unit 8, the control unit 9, and the output terminal 10 are provided.

  The water storage container 1 stores water necessary for generating hydrogen. The water storage container 1 is not particularly limited in material and shape as long as it can store water. For example, a tank for storing water similar to that used in a conventional hydrogen production apparatus can be adopted. . The water stored in the water storage container 1 may be a liquid containing at least water, such as neutral water, acidic aqueous solution, alkaline aqueous solution, etc., and a suitable one is selected according to the reactivity with the hydrogen generating material used. do it.

  The pump 2 supplies water in the water container 1 to the hydrogen generator 4.

  The pump control device 3 controls the operation of the pump 2 to adjust the amount of water supplied from the water container 1 to the hydrogen generator 4.

  The hydrogen generating unit 4 contains a hydrogen generating material that generates hydrogen by a reaction with water. The hydrogen generation unit 4 reacts the stored hydrogen generating material with water supplied from the water storage container 1 to generate hydrogen gas. As the hydrogen generation unit 4, for example, a unit provided with an inlet capable of injecting water into a container containing a hydrogen generating material and an outlet capable of discharging hydrogen gas generated in the container can be used. . The container is not particularly limited in material and shape as long as it can store a hydrogen generating material that generates hydrogen, but is preferably a material or shape that does not leak water or hydrogen. The specific container material is preferably a material that hardly permeates water and hydrogen and that does not break even when heated to about 120 ° C., for example, metals such as aluminum and iron, polyethylene, polypropylene, and polyether ether. Resins such as ketones can be used. Further, as the shape of the container, a prismatic shape, a cylindrical shape or the like can be adopted.

  The hydrogen generating material is not particularly limited as long as it contains a hydrogen generating material that reacts with water to generate hydrogen, but includes a hydrogen generating material that can react with water at a low temperature of 120 ° C. or lower to generate hydrogen. It is desirable. Examples of the hydrogen generating substance include metals such as aluminum, silicon, zinc, and magnesium, alloys mainly composed of one or more elements of aluminum, silicon, zinc, and magnesium, and also sodium borohydride, hydrogenated Metal hydrides such as potassium borohydride and lithium hydride can be preferably used. When the above alloy is used, metal components other than the main element are not particularly limited. The main element means an element contained in an amount of 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more based on the entire alloy. In addition, as a hydrogen generating substance, the thing of the said illustration may be used individually by 1 type, and 2 or more types may be used together.

  It is preferable that the hydrogen generating material further includes a heat generating material (a material other than the hydrogen generating material) that generates heat by reacting with water. In this case, even if water at a low temperature (for example, about 5 ° C.) is supplied, the temperature in the reaction system is increased by the heat generation of the exothermic substance, and rapid hydrogen generation becomes possible. Examples of the exothermic substance that reacts with water and generates heat include, for example, calcium oxide, magnesium oxide, calcium chloride, magnesium chloride, calcium sulfate, or the like, which becomes a hydroxide by reaction with water, or generates heat by hydration. And alkali metal or alkaline earth metal oxides, chlorides, sulfuric acid compounds and the like. In addition, those that generate hydrogen by reaction with water, such as metal hydrides such as sodium borohydride, potassium borohydride, and lithium hydride, can be used as a hydrogen generating substance as described above. However, it can also be used as a heat generating material when the above metal or alloy is used as a hydrogen generating material.

  In particular, when a metal such as aluminum, silicon, zinc, or magnesium or an alloy mainly composed of one or more elements selected from aluminum, silicon, zinc, and magnesium is used as the hydrogen generating substance, the above exothermic substance is used. It is preferable to use together. On the other hand, when the above metal hydride is used as the hydrogen generating material, hydrogen can be produced at a relatively good rate without using the above exothermic material. May be increased.

  The hydrogen gas pressure detector 5 detects the pressure of the hydrogen gas supplied from the hydrogen generator 4 to the fuel cell 6.

  The fuel cell 6 is composed of, for example, a polymer electrolyte fuel cell (PEFC). Specifically, the fuel cell 6 includes a plurality of cells each composed of an electrolyte and a pair of electrodes (a positive electrode and a negative electrode) that sandwich the electrolyte, thereby forming a stack. A solid polymer electrolyte is used as the electrolyte. Oxygen gas in the air (positive electrode active material) is supplied to the positive electrode by the air inflow portion 7, and hydrogen gas (negative electrode active material) generated in the hydrogen generation portion 4 is supplied to the negative electrode. Then, when the hydrogen ions of the negative electrode active material move to the positive electrode side through the electrolyte and combine with oxygen molecules, electrons move in the external circuit to generate power. The electrolyte, positive electrode active material, and negative electrode active material used in the fuel cell 6 are not limited to the above.

  The setting unit 8 sets the output voltage of the fuel cell 6. The setting unit 8 inputs electric power generated by the fuel cell 6 and outputs the electric power to the output terminal 10, and can be configured by, for example, a DC / DC converter. The power output from the output terminal 10 can be constant voltage control or constant current control.

  The control unit 9 controls the setting unit 8 so that the hydrogen gas pressure detected by the hydrogen gas pressure detection unit 5 falls within an appropriate range, thereby controlling the voltage of the fuel cell 6. The controller 9 is preferably configured by a microprocessor, but can also be configured by an electronic circuit or the like.

  Here, the appropriate range of hydrogen gas pressure refers to the range of hydrogen gas pressure during normal operation of the fuel cell system. When the hydrogen gas pressure is out of the proper range, as described above, problems such as the risk of the container and piping rupturing and the deterioration of the fuel cell occur.

  In this specification, the lower limit value of the appropriate range of the hydrogen gas pressure is defined as a first threshold value Pa, and the upper limit value of the appropriate range is defined as a second threshold value Pb.

  Next, the operation of the fuel cell system according to this embodiment will be described with reference to FIG. FIG. 2 is a flowchart for explaining the operation of the fuel cell system of the present embodiment. In addition, since the method of starting electric power generation and the method of ending electric power generation are the same as the past, the description is abbreviate | omitted here.

  While the fuel cell 6 is generating electric power, control by the control unit 9, that is, control for keeping the hydrogen gas pressure within an appropriate range is started (step S101). First, the hydrogen gas pressure detector 5 measures the pressure of the hydrogen gas supplied from the hydrogen generator 4 to the fuel cell 6 (step S102), and the controller 9 measures the hydrogen gas measured by the hydrogen gas pressure detector 5. It is determined whether the gas pressure is lower than the first threshold Pa (step S103).

  If the result of determination in step S103 is that the hydrogen gas pressure is greater than or equal to the first threshold value Pa, processing proceeds to step S105.

  As a result of the determination in step S103, when the hydrogen gas pressure is lower than the first threshold value Pa, the process proceeds to step S104, and the control unit 9 instructs the setting unit 8 to increase the set value of the output voltage of the fuel cell 6, and step Return to S102. By raising the set value of the output voltage of the fuel cell 6, the output current of the fuel cell 6 is reduced and the consumption of hydrogen gas is reduced, so that the hydrogen gas pressure can be increased. The method for increasing the set value of the output voltage may be a control for increasing the voltage by one step or a control for increasing the voltage in a plurality of steps. In the case of control for increasing the voltage in a plurality of stages, it is desirable to provide an upper limit value of the voltage.

  In step S105, the control unit 9 determines whether the hydrogen gas pressure measured by the hydrogen gas pressure detection unit 5 is higher than the second threshold value Pb.

  As a result of the determination in step S105, when the hydrogen gas pressure is equal to or lower than the second threshold value Pb, the process proceeds to step S107.

  As a result of the determination in step S105, when the hydrogen gas pressure is higher than the second threshold value Pb, the process proceeds to step S106, and the control unit 9 instructs the setting unit 8 to lower the set value of the output voltage of the fuel cell 6, and step Return to S102. Lowering the set value of the output voltage of the fuel cell 6 increases the output current of the fuel cell 6 and increases the consumption of hydrogen gas, so that the hydrogen gas pressure can be lowered. The method for lowering the set value of the output voltage may be a control for lowering the voltage by one step or a control for lowering the voltage in a plurality of steps. In the case of control for lowering the voltage in a plurality of stages, it is desirable to provide a lower limit value of the voltage.

  In step S107, the control unit 9 determines that the hydrogen gas pressure is within an appropriate range by the above processing, and instructs the setting unit 8 to set the output voltage of the fuel cell 6 to a normal set value. Return. The method of setting the output voltage of the fuel cell 6 to the normal set value may be set to the normal set value in one step, or the voltage is changed into a plurality of steps and set to the normal set value. Anyway.

  Next, the operation of the fuel cell system according to the present embodiment, in particular, the control method of the setting unit 8 by the control unit 9 will be described more specifically with reference to FIGS. FIG. 3 is a graph showing an example of the operation of the fuel cell system of the present embodiment, and FIG. 4 is a graph showing another example of the operation of the fuel cell system of the present embodiment. 3 and 4, Pa is a first threshold value that is a lower limit value of an appropriate range of hydrogen gas pressure, Pb is a second threshold value that is an upper limit value of an appropriate range of hydrogen gas pressure, and V1 is a normal voltage setting value. , V2 is a first voltage set value higher than the normal voltage set value V1, and V3 is a second voltage set value lower than the normal voltage set value V1.

  First, control when the hydrogen gas pressure becomes lower than the first threshold value Pa will be described with reference to FIG.

  In FIG. 3, at time t1, the hydrogen gas pressure is not less than the first threshold value Pa and not more than the second threshold value Pb, that is, the hydrogen gas pressure is within an appropriate range, so the output voltage of the fuel cell is a normal voltage. Set to set value V1. At time t2, the hydrogen gas pressure falls below the first threshold value Pa and falls outside the appropriate range, so the voltage setting value of the fuel cell is raised from V1 to V2. As a result, the output current of the fuel cell decreases, the consumption of hydrogen gas decreases, and the hydrogen gas pressure increases. At time t3, the hydrogen gas pressure is not less than the first threshold value Pa and not more than the second threshold value Pb, that is, the hydrogen gas pressure is within an appropriate range, so the voltage setting value of the fuel cell is returned from V2 to V1. .

  Next, control when the hydrogen gas pressure becomes higher than the second threshold value Pb will be described with reference to FIG.

  In FIG. 4, at time t4, the hydrogen gas pressure is not less than the first threshold value Pa and not more than the second threshold value Pb, that is, the hydrogen gas pressure is within an appropriate range, so the output voltage of the fuel cell is a normal voltage. Set to set value V1. At time t5, the hydrogen gas pressure becomes higher than the second threshold value Pb and falls outside the appropriate range, so the voltage setting value of the fuel cell is lowered from V1 to V3. As a result, the output current of the fuel cell increases, the consumption of hydrogen gas increases, and the hydrogen gas pressure decreases. At time t6, the hydrogen gas pressure is not less than the first threshold Pa and not more than the second threshold Pb, that is, the hydrogen gas pressure is within an appropriate range, so the voltage setting value of the fuel cell is returned from V3 to V1. .

  As described above, when the hydrogen gas pressure is lower than the first threshold value Pa, by performing control to increase the voltage setting value of the fuel cell, the output current of the fuel cell is reduced and the consumption of hydrogen gas is reduced. Therefore, the hydrogen gas pressure can be increased. On the other hand, when the hydrogen gas pressure becomes higher than the second threshold value Pb, the control of lowering the fuel cell voltage setting value increases the output current of the fuel cell and increases the consumption of hydrogen gas. The gas pressure can be lowered.

(Embodiment 2)
In the second embodiment, another example of the fuel cell system of the present invention will be described. FIG. 5 is a schematic configuration diagram showing the fuel cell system of the present embodiment. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. The present embodiment is different from the first embodiment in that the control unit 9 controls the pump control device 3.

  Next, the operation of the fuel cell system according to this embodiment will be described with reference to FIG. FIG. 6 is a flowchart for explaining the operation of the fuel cell system of the present embodiment. In addition, since the method of starting electric power generation and the method of ending electric power generation are the same as the past, the description is abbreviate | omitted here.

  While the fuel cell 6 is generating power, control by the control unit 9, that is, control for keeping the hydrogen gas pressure within an appropriate range is started (step S201). First, the hydrogen gas pressure detection unit 5 measures the pressure of the hydrogen gas supplied from the hydrogen generation unit 4 to the fuel cell 6 (step S202), and the control unit 9 measures the hydrogen gas measured by the hydrogen gas pressure detection unit 5. It is determined whether the gas pressure is lower than the first threshold Pa (step S203).

  If the result of determination in step S203 is that the hydrogen gas pressure is greater than or equal to the first threshold value Pa, processing proceeds to step S207.

  As a result of the determination in step S203, when the hydrogen gas pressure is lower than the first threshold value Pa, the process proceeds to step S204, where the control unit 9 instructs the setting unit 8 to increase the set value of the output voltage of the fuel cell 6, and step The process proceeds to S205. When the set value of the output voltage of the fuel cell 6 is increased, the output current of the fuel cell 6 is reduced and the consumption of hydrogen gas is reduced, so that the hydrogen gas pressure can be increased.

  In step S205, it is determined whether or not the state in which the hydrogen gas pressure is lower than the first threshold value Pa continues for a certain period of time.

  As a result of the determination in step S205, when the state where the hydrogen gas pressure is lower than the first threshold value Pa has not continued for a certain period of time, the process returns to step S202.

  As a result of the determination in step S205, when the state where the hydrogen gas pressure is lower than the first threshold value Pa continues for a certain time, the process proceeds to step S206, and the control unit 9 sends the pump control device 3 to the hydrogen generation unit 4. Is instructed to increase the amount of water supplied, and the process returns to step S202. When the amount of water supplied to the hydrogen generator 4 is increased, the amount of hydrogen gas generated in the hydrogen generator 4 is increased, so that the hydrogen gas pressure can be further increased. The method for increasing the amount of supplied water may be a control for increasing the amount of supplied water by one stage or a control for increasing the amount of supplied water in a plurality of stages. In the case of control for increasing the amount of water supplied in multiple stages, it is desirable to provide an upper limit value for the amount of water supplied.

  In step S207, the control unit 9 determines whether the hydrogen gas pressure measured by the hydrogen gas pressure detection unit 5 is higher than the second threshold value Pb.

  As a result of the determination in step S207, when the hydrogen gas pressure is equal to or lower than the second threshold value Pb, the process proceeds to step S211.

  If the result of determination in step S207 is that the hydrogen gas pressure is higher than the second threshold value Pb, the control unit 9 proceeds to step S208, instructs the setting unit 8 to decrease the set value of the output voltage of the fuel cell 6, and step The process proceeds to S209. When the set value of the output voltage of the fuel cell 6 is lowered, the output current of the fuel cell 6 increases and the consumption of hydrogen gas increases, so that the hydrogen gas pressure can be lowered.

  In step S209, it is determined whether or not the state in which the hydrogen gas pressure is higher than the second threshold value Pb continues for a certain period of time.

  As a result of the determination in step S209, when the state in which the pressure of the hydrogen gas is higher than the second threshold value Pb has not continued for a certain period of time, the process returns to step S202.

  As a result of the determination in step S209, when the state in which the pressure of the hydrogen gas is higher than the second threshold value Pb continues for a certain period of time, the process proceeds to step S210, and the control unit 9 instructs the hydrogen generator 4 to the pump controller 3. Is instructed to reduce the amount of water supplied to step S202, and the process returns to step S202. When the amount of water supplied to the hydrogen generating unit 4 is reduced, the amount of hydrogen gas generated in the hydrogen generating unit 4 is reduced, so that the hydrogen gas pressure can be further reduced. The method for reducing the amount of supplied water may be a control for reducing the amount of supplied water by one stage or a control for reducing the amount of supplied water in a plurality of stages. In the case of control for reducing the amount of supplied water in multiple stages, it is desirable to provide a lower limit value for the amount of supplied water.

  In step S211, the control unit 9 determines that the hydrogen gas pressure is within an appropriate range by the above processing, and instructs the setting unit 8 to set the output voltage of the fuel cell 6 to a normal set value. In step S212, the pump control device 3 is instructed to set the amount of water supplied to the hydrogen generator 4 to a normal water supply amount set value, and the flow returns to step S202. The method for setting the supply water amount to the normal supply water amount set value may be set to the normal set value in one step, or the supply water amount is changed in multiple steps and set to the normal set value. May be.

  Next, the operation of the fuel cell system of the present embodiment, in particular, the control method of the setting unit 8 and the pump control device 3 by the control unit 9 will be described more specifically with reference to FIGS. FIG. 7 is a graph showing an example of the operation of the fuel cell system of the present embodiment, and FIG. 8 is a graph showing another example of the operation of the fuel cell system of the present embodiment. 7 and 8, Pa is a first threshold value that is a lower limit value of the appropriate range of hydrogen gas pressure, Pb is a second threshold value that is an upper limit value of the appropriate range of hydrogen gas pressure, and V1 is a normal voltage setting value. , V2 is a first voltage set value higher than the normal voltage set value V1, V3 is a second voltage set value lower than the normal voltage set value V1, W1 is a normal supply water amount set value, and W2 is a normal supply water amount. A first supply water amount set value higher than the set value W1, W3 is a second supply water amount set value lower than the normal supply water amount set value W1.

  First, the control when the hydrogen gas pressure becomes lower than the first threshold Pa will be described with reference to FIG.

  In FIG. 7, at time t1, the hydrogen gas pressure is not less than the first threshold value Pa and not more than the second threshold value Pb, that is, the hydrogen gas pressure is within an appropriate range, so the output voltage of the fuel cell is a normal voltage. The set value V1 is set, and the amount of water supplied to the hydrogen generator is also set to the normal supply water amount set value W1. At time t2, the hydrogen gas pressure falls below the first threshold value Pa and falls outside the appropriate range, so the set value of the output voltage of the fuel cell is increased from V1 to V2. Thereafter, when the state in which the hydrogen gas pressure is lower than the first threshold value Pa is a time t7 in which the hydrogen gas pressure has continued for a certain period of time, the set value of the amount of water supplied to the hydrogen generator is increased from W1 to W2. Thereby, the generation amount of hydrogen gas increases and the hydrogen gas pressure also increases. At time t3, since the hydrogen gas pressure is not less than the first threshold Pa and not more than the second threshold Pb, that is, the hydrogen gas pressure is within an appropriate range, the set value of the output voltage of the fuel cell is changed from V2 to V1. The set value of the amount of water supplied to the hydrogen generator is also returned from W2 to W1.

  Next, control when the hydrogen gas pressure becomes higher than the second threshold value Pb will be described with reference to FIG.

  In FIG. 8, at time t4, the hydrogen gas pressure is not less than the first threshold value Pa and not more than the second threshold value Pb, that is, the hydrogen gas pressure is within an appropriate range, so the output voltage of the fuel cell is a normal voltage. The set value V1 is set, and the amount of water supplied to the hydrogen generator is also set to the normal supply water amount set value W1. At time t5, the hydrogen gas pressure becomes higher than the second threshold value Pb and falls outside the appropriate range, so the set value of the output voltage of the fuel cell is lowered from V1 to V3. Thereafter, when the state in which the hydrogen gas pressure is higher than the second threshold value Pb continues for a certain period of time t8, the set value of the amount of water supplied to the hydrogen generator is reduced from W1 to W3. Thereby, the generation amount of hydrogen gas is reduced, and the hydrogen gas pressure is also lowered. At time t6, the hydrogen gas pressure is not less than the first threshold value Pa and not more than the second threshold value Pb, that is, the hydrogen gas pressure is within an appropriate range. Therefore, the set value of the output voltage of the fuel cell is changed from V3 to V1. Then, the set value of the amount of water supplied to the hydrogen generator is also returned from W3 to W1.

  As described above, when the hydrogen gas pressure becomes lower than the first threshold value Pa, first, by performing control to increase the voltage setting value of the fuel cell, the output current of the fuel cell is reduced and the consumption amount of hydrogen gas Therefore, the hydrogen gas pressure can be increased. However, if the hydrogen gas pressure is lower than the first threshold value Pa for a certain period of time after increasing the voltage setting value of the fuel cell, by further performing control to increase the amount of water supplied to the hydrogen generation unit, Since the amount of hydrogen gas generation can be increased, the hydrogen gas pressure can be further increased. On the other hand, when the hydrogen gas pressure becomes higher than the second threshold value Pb, first, by performing control to lower the fuel cell voltage setting value, the output current of the fuel cell increases and the amount of hydrogen gas consumption increases. The hydrogen gas pressure can be lowered. However, if the hydrogen gas pressure is higher than the second threshold value Pa for a certain period of time after the fuel cell voltage setting value is lowered, by further controlling the amount of water supplied to the hydrogen generator, Since the amount of hydrogen gas generation can be reduced, the hydrogen gas pressure can be further reduced.

  In the first and second embodiments, the case where the setting unit 8 sets the output voltage of the fuel cell has been described. However, the output current is uniquely determined when the output voltage is determined under a certain condition. By setting the output current of the fuel cell, the hydrogen gas pressure can be controlled as in the case of setting the output voltage. Specifically, a relationship is established between the output voltage and the output current in that the output current decreases when the output voltage of the fuel cell is increased, and the output current increases when the output voltage is decreased. Therefore, if the output current of the fuel cell is lowered, the consumption of hydrogen gas can be increased to lower the hydrogen gas pressure, and if the output current of the fuel cell is increased, the consumption of hydrogen gas can be reduced to reduce the hydrogen gas pressure. Can be high.

  The fuel cell system of the present invention can be preferably used in various applications in which conventional fuel cells are used, including power supply applications for highly functional portable electronic devices such as cordless devices such as personal computers and mobile phones.

DESCRIPTION OF SYMBOLS 1 Water container 2 Pump 3 Pump control apparatus 4 Hydrogen generation part 5 Hydrogen gas pressure detection part 6 Fuel cell 7 Air inflow part 8 Setting part 9 Control part 10 Output terminal

Claims (4)

Containing a hydrogen generating material that generates hydrogen by an exothermic reaction with water, and reacting the hydrogen generating material with water to generate hydrogen; and
A water supply unit for supplying water to the hydrogen generation unit;
A fuel cell that generates electricity using hydrogen generated in the hydrogen generator as a fuel;
A hydrogen gas pressure detector for detecting the pressure of hydrogen gas supplied from the hydrogen generator to the fuel cell;
A setting unit for setting the output voltage or output current of the fuel cell;
And a control unit that controls the setting unit so that the pressure of the hydrogen gas detected by the hydrogen gas pressure detection unit is within an appropriate range. When the lower limit value of the appropriate range of the pressure of the hydrogen gas is a first threshold value, and the upper limit value of the appropriate range is a second threshold value,
The controller is
When the pressure of the hydrogen gas is lower than a first threshold, the setting unit is controlled to increase the output voltage of the fuel cell or decrease the output current of the fuel cell;
A fuel cell system that controls the setting unit to lower the output voltage of the fuel cell or increase the output current of the fuel cell when the pressure of the hydrogen gas is higher than the second threshold.   3. The fuel cell system according to claim 1, wherein, after the control of the setting unit, the control unit controls the water supply unit when a state in which the pressure of the hydrogen gas is outside an appropriate range continues for a predetermined time. The controller is
After the control of the setting unit, when the state in which the pressure of the hydrogen gas is lower than the first threshold continues for a certain time, the water supply unit is controlled to increase the amount of water supplied to the hydrogen generation unit,
4. The control of the water supply unit according to claim 3, wherein, after the setting unit is controlled, the water supply unit is controlled to reduce the amount of water supplied to the hydrogen generation unit when a state in which the pressure of the hydrogen gas is higher than the second threshold value continues for a predetermined time. The fuel cell system described.

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