JP2012178282A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell that appropriately removes impurities in a fuel electrode even if using a fuel supply source for generating a fuel by reacting a plurality of fuel precursors.SOLUTION: The fuel cell includes: a power generation section 2 having a fuel electrode 23, an oxidant electrode 22 and a solid polymer electrolyte membrane 21; a fuel electrode section having a fuel supply space 25 supplied with a fuel; and a fuel supply source 3 for bringing a plurality of fuel precursors 32 into contact with each other and causing a chemical reaction to generate the fuel and supplying the fuel. The fuel supply source has a plurality of storage sections for storing the plurality of fuel precursors, respectively, and a fuel control mechanism 33 for moving at least the fuel precursor stored in either storage section to the other storage section. The fuel control mechanism performs supply control of controlling the fuel precursor movement according to a physical quantity related to impurities accumulated in the fuel electrode by the reaction of the fuel with an oxidant, so that the pressure of the fuel caused by the supply control removes at least part of the impurities.

Description

  The present invention relates to a fuel cell including a power generation unit and a fuel storage source.

  Currently, there are many types of fuel cells. However, fuel cells used in electronic devices are promising to be applied to polymer electrolyte fuel cells because the system can be easily downsized and simplified. A polymer electrolyte fuel cell is composed of a unit cell comprising a fuel electrode, an oxidant electrode, and a solid polymer electrolyte membrane sandwiched between the two electrodes, and supplies fuel such as methanol and hydrogen to the fuel electrode side, An oxidant gas such as oxygen or air is supplied to the pole side, and electric power is generated by these electrochemical reactions. Among them, direct hydrogen fuel cells that supply hydrogen to the fuel electrode are attracting attention because of their high power generation voltage. Direct hydrogen fuel cells are broadly divided into a flow system that circulates hydrogen on the fuel electrode side and a dead-end system that does not circulate hydrogen. Especially in mobile devices such as laptop computers and mobile phones, there are auxiliary devices, etc. The dead-end system with fewer components is suitable because it is easy to increase the energy density.

  By the way, water is generated at the oxidant electrode during the power generation reaction of the fuel cell. Most of the water generated at the oxidizer electrode evaporates into the air, but the water moves to the fuel electrode through the solid polymer electrolyte membrane depending on the operating environment such as temperature and humidity, and moves to the fuel electrode as back-diffused water. In the flow type fuel cell, the reverse diffusion water moves from the fuel electrode as the fuel gas moves and is removed from the fuel electrode. However, in the dead end type fuel cell, the movement speed of the fuel gas is slow. May accumulate without moving from the fuel electrode. If the amount of reverse diffusion water is small, there is no effect on the power generation reaction of the fuel cell. However, if continuous power generation is performed, the surface of the catalyst layer of the fuel electrode is covered, causing an increase in diffusion overvoltage, resulting in a significant decrease in power generation performance. May be invited.

  In response to the above problem, a method has been proposed in which water present in the fuel electrode is removed by temporarily supplying hydrogen to the fuel electrode at a higher pressure than in normal operation (see, for example, Patent Document 1). The fuel cell according to Patent Document 1 controls a power generation unit, a fuel flow path for distributing fuel gas supplied from a fuel supply source to the power generation unit, and a fuel gas pressure in the fuel flow path higher than a normal operation pressure. And an impurity discharge mechanism that operates by high pressure control of the pressure control mechanism and discharges water in the fuel flow path and other impurities that interfere with power generation to the outside of the fuel cell. In the fuel cell according to Patent Document 1, the state of the fuel cell is monitored, and when a predetermined time has elapsed since the start of power generation, or when the voltage of the fuel cell falls below a predetermined value, or the impurity concentration in the fuel cell When the fuel cell pressure exceeds a predetermined value, or when the fuel concentration in the fuel cell falls below a predetermined value, the pressure in the fuel flow path is increased. In addition, an impurity discharge mechanism is provided that opens only when the pressure exceeds a predetermined value in order to release impurities in the fuel cell to the outside as the pressure control mechanism operates. According to the above operation, it is possible to remove impurities in the fuel flow path from the power generation unit.

  However, in the fuel cell according to Patent Document 1 described above, a regulator valve is used for the pressure control mechanism, and the fuel supply source must always supply high-pressure fuel. Therefore, the fuel supply source includes a hydrogen storage alloy or high-pressure hydrogen. A cylinder is used. Since the fuel supply source has a high pressure resistance, it has a very robust structure and the fuel cell system becomes large.

  Further, as a fuel supply source, a fuel gas generator that generates a fuel gas by reacting a plurality of types of fuel precursors such as a hydrogen compound and water and supplies the fuel gas to a power generation unit may be used. Such a fuel supply source can be driven at a relatively low pressure in order to generate as much fuel as necessary for power generation, and does not require a robust structure, so that the fuel cell system can be miniaturized. . However, in order to supply fuel to the fuel flow path at a low pressure, the primary pressure input to the regulator valve is low even if the technique according to Patent Document 1 is applied, so that impurities in the fuel flow path can be sufficiently eliminated. Is difficult.

JP 2008-41647 A

  Therefore, the present invention has been made in view of the above situation, and even when a fuel supply source that generates fuel by reacting a plurality of fuel precursors is used, a fuel that can appropriately remove impurities in the fuel electrode. The purpose is to provide batteries.

  The first feature of the fuel cell of the present invention for solving the above problems is that a fuel electrode to which fuel is supplied, an oxidant electrode to which an oxidant is supplied, a solid polymer sandwiched between the fuel electrode and the oxidant electrode A power generation unit including an electrolyte membrane, a fuel electrode unit provided on the power generation unit so as to face a surface on which the electrolyte membrane of the fuel electrode is disposed, and having a fuel supply space to which fuel is supplied, and a plurality of fuel precursors A fuel supply source that generates fuel by contacting and performing a chemical reaction and supplies fuel to the fuel electrode portion, and the fuel supply source includes a plurality of storage portions that respectively store a plurality of fuel precursors A fuel control mechanism that moves a fuel precursor stored in at least one of the plurality of fuel precursors to the other storage, and the fuel control mechanism includes the fuel and the oxidant. Concerning impurities accumulated in the fuel electrode due to the reaction of Perform supply control for controlling the movement of the fuel precursor based on the physical quantity, at least a portion of the impurities is summarized in that it is intended to be removed by the pressure of the fuel generated by the feed control.

  According to such a feature, in a fuel cell that supplies fuel generated by reacting a fuel precursor inside the storage unit to the power generation unit, the amount of generated fuel is changed to move impurities accumulated in the fuel electrode to generate power. Performance recovery can be performed.

  According to a second feature of the fuel cell of the present invention, in the fuel cell of the first feature, the fuel control mechanism includes a physical quantity detection unit that detects a physical quantity related to the impurity, and the physical quantity calculation unit includes the impurity in the fuel electrode. The gist is to perform an increase supply control for increasing the movement of the fuel precursor when a physical quantity indicating that a predetermined amount or more has been accumulated is calculated.

  According to such a feature, the amount of impurities that need to be removed is detected in the fuel electrode, and the speed at which the fuel precursor reacts is increased, so that the fuel is fed to the fuel electrode at a faster speed than in normal operation. Since the fuel is supplied, the impurities accumulated in the fuel electrode by the injected fuel can be moved at an appropriate timing.

  According to a third feature of the fuel cell of the present invention, in the fuel cell of the second feature, the fuel control mechanism includes a physical quantity detection unit that detects a physical quantity related to the impurity, and the physical quantity calculation unit includes the impurity in the fuel electrode. The gist is to perform a decrease supply control that reduces the movement of the fuel precursor when calculating a physical quantity indicating that a predetermined amount or more has been accumulated, and an increase supply control that increases the movement of the fuel precursor after the decrease supply control. To do.

  According to this feature, in addition to the effect of the fuel cell of the second feature, the amount of fuel supplied at a faster speed than in normal operation increases, and fuel is injected and supplied to the fuel electrode portion for a longer time. Therefore, the movement of impurities accumulated in the fuel electrode can be performed more reliably.

  According to a fourth aspect of the fuel cell of the present invention, in the fuel cell according to the third aspect, an open state in which fuel is supplied to the fuel electrode portion and a fuel electrode between the fuel supply source and the power generation portion. A fuel valve is provided that maintains either a closed state in which no fuel is supplied to the unit, and the fuel valve is in a closed state when the fuel control mechanism is performing a decrease supply control.

  According to such a feature, since the supply speed of the fuel supplied to the fuel electrode portion can temporarily increase, the impurities accumulated in the fuel electrode can be moved more reliably.

  According to a fifth feature of the fuel cell of the present invention, in the fuel cell according to any one of the first to fourth features, the fuel electrode portion is connected to a discharge portion that discharges impurities inside the fuel electrode portion. Is the gist.

  According to this feature, the impurities accumulated in the fuel electrode are moved to the discharge portion by the fuel whose supply speed is increased by the pressure difference, so that the impurities in the fuel electrode portion can be more reliably removed.

  According to a sixth feature of the fuel cell of the present invention, in the fuel cell of the fifth feature, the fuel electrode portion and the discharge portion are detachable, and the fuel electrode portion is between the fuel electrode portion and the discharge portion. A discharge valve is provided to maintain either an open state in which impurities inside the fuel cell are discharged to the discharge part or a closed state in which impurities inside the fuel electrode part are not discharged to the discharge part. It is a summary.

  According to this feature, the impurities moved into the discharge part can be removed to the outside of the fuel cell device by exchanging the discharge part, and the number of impurities removed during continuous operation can be greatly increased.

  According to a seventh feature of the fuel cell of the present invention, in the fuel cell according to any one of the first to sixth features, the fuel electrode portion is supplied with fuel in a direction perpendicular to the surface direction of the fuel electrode. The gist is to provide a fuel flow path.

  According to such a feature, the fuel can be supplied while maintaining a high supply speed to the vicinity of the fuel electrode by passing through the fuel flow path, so that impurities can be more reliably removed.

  An eighth feature of the fuel cell according to the present invention is that, in the fuel cell according to the seventh feature, the fuel flow path includes a diffusion portion in which the fuel diffuses in the surface direction of the fuel electrode.

  According to this feature, the fuel supplied from the fuel flow path is supplied over a wide range along the fuel electrode by the diffusion section, so that impurities can be removed in a wider range.

  A ninth feature of the fuel cell of the present invention is that, in the fuel cell of the fifth or sixth feature, the fuel supply space is a groove provided for the fuel electrode.

  According to this feature, since the fuel supply space is formed in a groove shape, when impurities accumulate in the fuel supply space, the impurities can be more reliably moved to the discharge portion.

  According to a tenth feature of the fuel cell of the present invention, in the fuel cell according to any one of the second to ninth features, the physical quantity is a voltage value of the power generation unit, and the physical quantity detection unit has a voltage value of a predetermined value or less. The gist is to detect the state that becomes.

  According to this feature, the fuel cell voltage is read and the decrease supply control or the increase supply control is controlled, so that water in the fuel electrode can be removed safely without applying an excessive load to the fuel cell. .

  According to an eleventh feature of the fuel cell of the present invention, in the fuel cell according to any one of the second to ninth features, the physical quantity is a current value of the power generation unit, and the physical quantity detection unit has a current value of a predetermined value or more. The gist is to detect the state that becomes.

  According to such a feature, the fuel cell current is read to control the decrease supply control or the increase supply control, so that the fuel cell water can be safely removed without applying an excessive load to the fuel cell. I can do it.

  According to a twelfth feature of the fuel cell of the present invention, in the fuel cell according to any one of the second to ninth features, the physical quantity is a time from when the fuel cell starts power generation. The gist is to detect a state in which a predetermined time has passed.

  According to such a feature, since the time after the fuel cell starts power generation is read and the stop control and the supply control are periodically switched, impurities can be removed more reliably.

  A thirteenth feature of the fuel cell according to the present invention is that, in the fuel cell according to any one of the fourth to twelfth features, the storage portion and the discharge portion have a cartridge structure that is removable from the power generation portion. And

  According to this feature, in a portable fuel cell, power can be generated continuously by exchanging cartridges, so that power generation can be performed for a long time.

  According to the present invention, it is possible to provide a fuel cell that can appropriately remove impurities in the fuel electrode even when a fuel supply source that generates fuel by reacting a plurality of fuel precursors is used. .

1 is an overall schematic configuration of a fuel cell 1 according to an embodiment of the present invention. It is the schematic of the fuel cell in the form 1 of the Example of this invention. It is the elements on larger scale of a solid polymer electrolyte membrane, an oxidizing agent electrode, and a fuel electrode. It is a transition diagram of the voltage of a fuel cell and fuel pressure in Embodiment 1 of the present invention. It is a transition diagram of the voltage of a fuel cell and fuel pressure in Embodiment 2 of the present invention. It is the schematic of the fuel cell in Embodiment 3 of this invention. It is the schematic of the fuel cell in Embodiment 4 of this invention. It is an expanded sectional view of the fuel electrode part in Embodiment 5 of this invention. It is an expanded sectional view of the fuel electrode part in the modification of Embodiment 5 of this invention. It is a disassembled perspective view of the fuel electrode part in Embodiment 6 of this invention.

(Embodiment 1)
An example of the fuel cell 1 according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration of an entire fuel cell 1 according to an embodiment of the present invention, FIG. 2 is a schematic diagram of the fuel cell 1, and FIG. 3 is a solid polymer electrolyte membrane 21, an oxidant electrode 22, and a fuel electrode 23. FIG. 4 shows a transition diagram of the voltage of the power generation unit 2 and the pressure of the fuel when the fuel cell 1 of this embodiment is operated.

  As shown in FIG. 1, the fuel cell 1 includes a power generation unit 2 and a fuel supply source 3.

  As shown in FIG. 2, the power generation unit 2 includes an oxidant electrode 22 to which an oxidant is supplied and a fuel electrode 23 to which a fuel is supplied on both surfaces of the solid polymer electrolyte membrane 21. Here, oxygen in the atmosphere is usually used as the oxidizer, but pure oxygen may be supplied by an oxygen cylinder or the like in order to eliminate impurities such as nitrogen. An example of the fuel provided to the fuel electrode 23 is hydrogen. The fuel is obtained by reacting a plurality of fuel precursors 32 respectively stored in a plurality of storage units inside the fuel supply source 3 in a reaction unit 31 which is a part of the plurality of storage units. Specific examples of the fuel precursor 32 include a hydrogenated compound such as sodium borohydride and aluminum hydride, a catalyst solution containing a metal such as aluminum, water, and a catalyst, and the hydrogenated compound, metal, water, and catalyst. It is known that a hydrogen generation reaction occurs when the solution is brought into contact. In order to cause the plurality of fuel precursors 32 to react, there is a method in which the fuel control mechanism 33 supplies one fuel precursor 2 to the reaction unit 31 in which the other fuel precursor 2 exists. There is also a method in which a plurality of fuel precursors 2 installed in a storage unit that is not the reaction unit 31 are simultaneously sent to the reaction unit 31 by the fuel control mechanism 33. The technique of the present invention is applied to a system in which at least one fuel precursor 32 is generated by moving the fuel control mechanism 33 to a location different from that before the reaction. As a matter of course, no fuel is generated in such a system unless the fuel precursor 32 is supplied to the reaction section 31. In this specification, the fuel control mechanism 33 controls the operation of supplying the fuel precursor 32 to the reaction unit 31, and stops the state where the fuel control mechanism 33 does not supply the fuel precursor 32 to the reaction unit 31. Called control. Further, the power generation unit 2 determines the fuel generation speed during the supply control in the fuel supply source 3 so that the fuel can be stably supplied even during high-load operation that generates larger electric power than during normal operation. It is preferable that it is faster than the fuel consumption rate used for power generation.

  If the plurality of fuel precursors 32 do not react at an appropriate timing, the generated fuel will be excessive and the power generation unit 2 will be in a high pressure state, or the generated fuel will be low, so that the power generation performance will be reduced due to insufficient fuel. Invite. Therefore, it is necessary to control the supply of the fuel precursor 32, but there are several types of supply control. One is that the fuel control mechanism 33 detects the internal pressure of the fuel supply space 25, and if the pressure in the reaction unit 31 is lower than the pressure in the fuel supply space 25, the fuel precursor 32 is moved to the reaction unit 31 and the fuel is supplied. Is generated. Conversely, when the pressure in the reaction unit 31 is high, the movement of the fuel precursor 32 to the reaction unit 31 is stopped. With this control method, the internal pressure of the fuel supply space 25 can be kept substantially constant, and the power generation unit 2 can generate power. Note that this control method also includes a structure in which the means for detecting the internal pressure of the fuel supply space 25 itself moves the fuel precursor 32 without using electric power.

  As another control method, the fuel control mechanism 33 detects the power generation amount of the power generation unit 2, calculates the amount of fuel consumed from the power generation amount, and generates the required amount of fuel as the fuel precursor 32. Is to react. In the control method using the pressure, since the pressure fluctuates due to the consumption of fuel by power generation in the power generation unit 2, there is a possibility that a slight delay occurs in the shift to the supply control and the stop control. However, with the control method for calculating the fuel consumption, the above-described delay does not occur, and the power generation unit 2 can generate power while keeping the internal pressure of the fuel supply space 25 substantially constant.

  Other control methods are limited to cases where the amount of power generated by the power generation unit 2 is constant or when fluctuations in the generated power are known in detail. In addition, supply control and stop control are performed. According to this control method, similarly to the above-described control method for detecting the power generation amount, there is no delay, and it is possible to generate power in the power generation unit 2 while keeping the internal pressure of the fuel supply space 25 substantially constant.

  Although the fuel generation flow rate is controlled to an appropriate value by the above control method, the control method is not limited to the above example as long as it is a control method for generating fuel necessary for the power generation amount of the power generation unit 2. In addition, these control methods for generating fuel in the fuel cell 1 of the present invention may be used alone or in combination with a plurality of control methods.

  In order to prevent the supplied fuel from leaking to the outside of the power generation unit 2, the power generation unit 2 has a fuel electrode unit 26 having a fuel supply space 25 surrounded by an outer wall 24. The space 25 is provided so as to face the surface of the fuel electrode 23 on which the solid polymer electrolyte membrane 21 is disposed. For the same reason, it is preferable that a sealing means is provided at a location where the solid polymer electrolyte membrane 21 and the outer wall 24 are in contact with each other. Examples of the sealing means include a seal using packing / adhesive and a sealing method such as heat-sealing the solid polymer electrolyte membrane 21 to the outer wall 24. The contact between the solid polymer electrolyte membrane 21 and the outer wall 24 is available. The method is not limited to this as long as the confidentiality of the part can be obtained. Thus, the fuel is supplied from the fuel supply source 3 to the fuel supply space 25 that becomes a closed space by the sealing means. In addition, as shown in FIG. 2, when the power generation unit 2 and the fuel supply source 3 are provided at a distance from each other and it is difficult to supply fuel directly from the fuel supply source 3 to the power generation unit 2, It is also possible to use a fuel supply path 34 such as a pipe or tube through which the fuel can move.

  Next, the detailed configuration of the oxidant electrode 22 and the fuel electrode 23 and the power generation operation of the power generation unit 2 will be described with reference to FIG. The solid polymer electrolyte membrane 21 has a catalyst layer on its surface, which is a layer in which carbon particles carrying a catalyst typified by platinum, ruthenium, and cobalt are coated on the entire surface. The catalyst layers are arranged on both surfaces such as a catalyst layer 221 on the oxidant electrode 22 side and a catalyst layer 231 on the fuel electrode 23 side. Furthermore, it is preferable that the surfaces of the catalyst layers on both sides have gas diffusion layers 222 and 232 on both sides of the oxidant electrode 22 side and the fuel electrode 23 side, which have both conductivity and air permeability. The gas diffusion layers 222 and 232 are porous so as to permeate the fuel, and are formed of a conductor such as metal or carbon in order to obtain conductivity.

  The fuel given to the fuel supply space 25 reaches the catalyst layer 231 on the fuel electrode 23 side through the holes in the gas diffusion layer 232, and the following reaction occurs on the catalyst and changes into protons and electrons.

H ₂ → 2H ⁺ + 2e ⁻ (Formula 1)
Protons generated on the catalyst move through the solid polymer electrolyte membrane 21 and are transported to the catalyst layer 221 on the oxidant electrode 22 side. Further, the electrons move in the gas diffusion layer 232 having higher conductivity than the catalyst layer and move to an external circuit (not shown). An electronic device driven by the power generated by the fuel cell 1 is connected to the end of the external circuit, and further connected to the gas diffusion layer 222 on the oxidant electrode 22 side.

  On the other hand, oxygen in the air reaches the catalyst layer 221 on the oxidant electrode 22 side through holes in the gas diffusion layer 222 on the oxidant electrode 22 side. The catalyst layer 221 on the oxidant electrode 22 side generates water by causing the following reaction with protons and oxygen transported through the solid polymer electrolyte membrane 21 and electrons moved through the external circuit.

(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (Formula 2)
Through such an electrochemical reaction, the fuel cell 1 can generate electric power and drive an electronic device. In addition, although the example of the catalyst was mentioned above, the kind of catalyst will not be restricted to this if it can produce | generate a proton in the electric power generation reaction of the electric power generation part 2. FIG. The gas diffusion layers 222 and 232 have a lower electric resistance than the catalyst layers 221 and 231, but have a higher electric resistance than metals and carbon. Therefore, when the area of the solid polymer electrolyte membrane 21 is large, an external circuit is used. A resistance component is added while moving to the voltage, and the voltage drops. In order to improve such a voltage drop, a carbon resin having higher conductivity than the gas diffusion layers 222 and 232 so as to be in contact with the surface of the gas diffusion layers 222 and 232 opposite to the surface in contact with the catalyst layers 221 and 231 An electrode plate made of metal may be provided.

  Here, most of the water generated at the oxidant electrode 22 evaporates into the air facing the oxidant electrode 22, but part of the water permeates to the fuel electrode 23 through the solid polymer electrolyte membrane 21. The water that has moved to the fuel electrode 23 evaporates into the fuel supply space 25. However, since the fuel supply space 25 is a closed space, when the vapor pressure reaches the saturated water vapor pressure at the operating temperature, the water becomes fuel as droplets. It begins to accumulate in the pole part 26. Further, when the oxidant electrode 22 faces the atmosphere, gas in the air permeates through the solid polymer electrolyte membrane 21 to the fuel supply space 25. Of the main components of the permeating gas, oxygen undergoes a proton reaction on the fuel electrode to become water, but nitrogen continues to remain inside the fuel supply space 25. In this specification, the above water, nitrogen, and the like are used as impurities.

  The resistance component in the power generation of the power generation unit 2 can be broadly divided into three types: active overvoltage related to the reaction on the catalyst, resistance overvoltage due to the electrical resistance of the constituent members, and diffusion overvoltage due to fuel supply inhibition. The diffusion overvoltage increases when the supply of fuel to the fuel electrode 23 is hindered by impurities covering the surface of the fuel electrode 23, or when the amount of fuel supplied to the fuel electrode 23 decreases due to insufficient fuel.

  Next, the operation of the fuel cell 1 of the present invention will be described with reference to FIG. During normal operation, the fuel control mechanism 33 repeats supply control and stop control to supply fuel to the fuel electrode 23 at a substantially constant pressure. When the power generation unit 2 generates power in this state, water is collected almost uniformly on the entire surface of the fuel electrode part 26 as described above, and the accumulated water covers the fuel electrode 23 and supplies fuel to the catalyst layer 231. Inhibiting, the voltage of the power generation unit 2 gradually decreases as shown in FIG. 4 (section a). Therefore, when water accumulates at a predetermined amount or more in the fuel electrode portion 26, the fuel control mechanism 33 shifts to an increase supply control in which the moving speed of the fuel precursor 32 is increased to generate more fuel than the amount of fuel consumed in the section a. Transition (t1). The amount of fuel generated by the fuel supply source 3 while the increased supply control is maintained for a certain period of time is larger than the amount of fuel consumed at that time, and more fuel is continuously supplied to the fuel supply space than during normal operation. To be sprayed to 25. The impurities covering the fuel electrode 23 receive a continuous supply of fuel, so that the impurities covering the fuel electrode 23 are skipped and collected in a part of the fuel supply space 25 (section b). . Further, at this time, the pressure in the fuel supply space becomes higher than the pressure used in the normal operation for generating more hydrogen than the consumption by the increase supply control. After the return operation, the fuel control mechanism 33 shifts to stop control, and stops the supply of fuel to the fuel electrode 23 (t2). Thereafter, since the power generation unit 2 continues to generate power, the fuel electrode 23 continues to consume fuel, and the pressure in the fuel supply space 3 decreases. When the pressure in the fuel supply space 3 decreases to the pressure during normal operation, the fuel control mechanism 33 returns to the control method during normal operation. When the supply of fuel to the fuel electrode 23 is again hindered by water, the power generation performance is recovered by performing a return operation.

  Here, in the present embodiment, it is required that the fuel control mechanism 33 appropriately shift from the normal operation to the increase supply control, and there are several methods as shown below.

≪Control pattern 1≫
The fuel control mechanism 33 includes means for detecting a voltage between the oxidant electrode 22 and the fuel electrode 23, and the fuel control mechanism is activated when the voltage of the power generation unit 2 becomes equal to or lower than a predetermined pressure. Transition from normal operation to increased supply control. The operating voltage of the power generation unit 2 varies depending on the amount of power required by the equipment used, but it is desirable to operate at a voltage value around 0.7 V during normal operation. When the normal operation is continued and the voltage value is reduced to the first predetermined value due to an increase in diffusion overvoltage caused by impurities covering the fuel electrode 23, the fuel control mechanism 33 receives the voltage information and receives the fuel electrode portion 26. It is determined that water has accumulated, and control is shifted from normal operation control to increased supply control. In the present invention, the first predetermined value of the voltage value may be set to any value as long as it is 0 V or more. However, the deterioration of the membrane electrode assembly including the solid polymer electrolyte membrane 21 and the catalyst layers 221 and 231 is prevented. It is desirable to set it to 0.2V or more from the viewpoint.

Although it is desirable that the voltage of the power generation unit 2 be restored to the same level as that during normal operation by the returning operation, it is difficult to completely remove impurities clogged in the fine holes of the gas diffusion layer 232. If the voltage is recovered after the return operation, the increase supply control may be ended and the control may be shifted to the normal operation control even in a state lower than the voltage during the normal operation.
≪Control pattern 2≫
The fuel control mechanism 33 includes means for detecting a current value of the power generation state of the power generation unit 2, and when the current of the power generation unit 2 exceeds a predetermined value, the fuel control mechanism 33 performs normal operation. Shift from control to increased supply control. Since the current during normal power generation of the power generation unit 2 depends on the size of the power generation effective area determined by the solid polymer electrolyte membrane 21, the oxidant electrode 22, and the fuel electrode 23, the size cannot be generally described. As shown in control pattern 1, it is desirable that the current value corresponds to a voltage value in the vicinity of 0.7 V during normal operation. Similarly to the control pattern 1, the timing for ending the increased supply control is lower than the current during normal operation if the current value is reduced to a value corresponding to the voltage when the voltage recovers at least after the return operation. May be.
<< Control pattern 3 >>
The fuel control mechanism 33 is provided with means for detecting the power generation time of the power generation unit 2, and when the power generation time of the power generation unit 2 has passed a predetermined time, the fuel control mechanism 33 is increased from normal operation control. Transition to control. Although it varies depending on the environmental temperature and humidity at which power generation is performed, when the required power in the electronic device used is constant, it is possible to predict how much impurities have covered the surface of the fuel electrode 23 over time. it can. For this reason, a time during which impurities accumulate in the fuel electrode portion 26 and a return operation is necessary is set in advance, and the fuel control mechanism 33 receives the power generation time information of the power generation portion 2 to cover the surface of the fuel electrode portion 23 with the impurities. And the transition from normal operation to increased supply control is performed. When the increase supply control is terminated, the time after the start of the increase supply control is detected, and the increase supply control is terminated when it is detected that a sufficient time has passed for removing impurities. To do.

  The above control pattern can be applied to the transition from the normal operation control to the increase supply control and the control to the end of the increase supply control. However, the present invention is not limited to this as long as it can detect the amount of impurities accumulated in the fuel electrode portion 26. Further, in the above control pattern, the fuel control mechanism 33 operates in accordance with the power generation status of the power generation unit 2, so that an electromagnetic valve is applied to the fuel control mechanism 33.

  Although applicable to all control patterns, the timing for ending the increased supply control may be controlled by the pressure value. The fuel control mechanism 33 is provided with means for detecting the fuel pressure of the fuel electrode part 26, and when the fuel pressure of the fuel electrode part 26 becomes equal to or higher than a predetermined value after the stop control is started, the fuel control mechanism 33. Shift from increased supply control to stop control. The predetermined value is set lower than the pressure at which the fuel cell 1 is damaged in order to prevent the fuel in the fuel electrode portion 26 from becoming too high and damaging the fuel cell 1.

  The transition from the normal operation to the increase supply control and the shift from the increase supply control to the normal operation may be performed by different triggers. For example, the shift from the normal operation to the increase supply control may be performed by the control pattern 1 using the detection of the voltage, and the shift from the increase supply control to the normal operation may be performed by the detection of the pressure.

As described above, even when the fuel electrode 23 is covered with impurities and the fuel is inhibited by the catalyst layer 231 and the power generation performance of the power generation unit 2 is reduced, the fuel electrode 23 is fueled at a higher speed than during normal operation. The power generation performance of the power generation unit 2 can be recovered by removing impurities at an appropriate timing.
(Embodiment 2)
FIG. 5 shows a transition diagram of the voltage of the power generation unit 2 and the pressure of the fuel when the power generation unit 2 according to Embodiment 2 of the present invention is operated. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description of similar configurations and operations is omitted. Hereinafter, the second embodiment will be described with reference to FIG.

  The power generation unit 2 according to the second embodiment of the present invention has the same configuration as that of the power generation unit 2 according to the first embodiment, except that the method for controlling the supply of the fuel precursor 32 of the fuel control mechanism 33 is different. The fuel control mechanism 32 performs a reduction supply control for moving the fuel precursor 32 to generate a fuel that is smaller than the fuel consumption during the normal operation of the power generation unit 2, and then the fuel control mechanism 32 determines the fuel consumption during the normal operation. In order to generate a large amount of fuel, an increase supply control for moving the fuel precursor 32 is performed.

  The second embodiment will be described in accordance with the voltage and pressure transition diagram of the power generation unit 2 in FIG. When the power generation unit 2 continues normal power generation for a long time, impurities accumulate in the fuel electrode portion 26 and the fuel electrode 23 is covered, so that the diffusion overvoltage increases and the power generation voltage of the power generation unit 2 decreases. The fuel control mechanism 33 shifts to the decrease supply control when the impurities are accumulated in the fuel electrode portion 26 by a predetermined amount or more (t3). In order to reduce the amount of fuel generated in the decrease supply control, the supply rate of the fuel precursor 32 is made slower than that during normal operation, or the supply of the fuel precursor 32 is completely stopped. Since the amount of fuel supplied to the fuel supply space 25 decreases, the partial pressure of the fuel in the fuel supply space 25 gradually decreases. Since the decrease in the fuel partial pressure causes an increase in the diffusion overvoltage, the power generation voltage of the power generation unit 2 decreases as the fuel partial pressure decreases (section c). When power generation in the decrease supply control is continued and the partial pressure of the fuel in the fuel supply space 25 decreases to a predetermined pressure, the fuel control mechanism 33 shifts to the increase supply control state (t4). The amount of fuel generated by the fuel supply source 3 is larger than the amount of fuel consumed at the time when the increased supply control is maintained for a certain time, and more fuel is continuously supplied to the fuel supply space 25 than during normal operation. Supplied to be sprayed with. In addition, since the power generation is performed under the reduced supply control, the internal pressure of the fuel supply space 25 is reduced, and the fuel is supplied to the fuel supply space 25 more than the configuration of the power generation unit shown in the first or second embodiment. Done for a long time. The impurities covering the fuel electrode 23 receive a continuous supply of fuel, so that the impurities covering the fuel electrode 23 are skipped and collected in a part of the fuel supply space 25 (section b). . Further, at this time, the pressure in the fuel supply space 25 becomes higher than the pressure used in the normal operation for generating more hydrogen than the consumption by the increase supply control. After the return operation, the fuel control mechanism 33 shifts to stop control and stops the supply of fuel to the fuel electrode 23 (t5). Thereafter, since the power generation unit 2 continues to generate power, the fuel electrode 23 continues to consume fuel, and the pressure in the fuel supply space 25 decreases. When the pressure in the fuel supply space 25 decreases to the pressure during normal operation, the fuel control mechanism 33 returns to the control method during normal operation. When the supply of fuel to the fuel electrode 23 is again hindered by water, the power generation performance is recovered by performing a return operation.

In the present embodiment, the fuel control mechanism 33 is switched from the normal operation control to the decrease supply control in the control pattern 1 to 3 in the first embodiment, and is switched from the normal operation to the increase supply control. As a switching control method from control to normal operation control, the switching method from normal operation to increase supply control in the control patterns 1 to 3 in the first embodiment can be applied.
<< Control pattern 4 >>
The fuel control mechanism 33 includes means for detecting a voltage between the oxidant electrode 22 and the fuel electrode 23, and the fuel control mechanism 33 when the voltage of the power generation unit 2 becomes a predetermined pressure or less. Is shifted from the normal operation state to the reduced supply control. The operating voltage of the power generation unit 2 varies depending on the amount of power required by the equipment used, but it is desirable to operate at a voltage value around 0.7 V during normal operation. When the normal operation is continued and the voltage value decreases to the second predetermined value due to an increase in diffusion overvoltage caused by impurities covering the fuel electrode 23, the fuel control mechanism 33 receives the voltage information and receives the fuel electrode portion 26. It is determined that water has accumulated, and control is shifted from normal operation control to reduced supply control. Thereafter, the transition from the decrease supply control to the increase supply control is preferably performed when the voltage drops to the first predetermined value. The second predetermined value may be equal to or less than the first predetermined value, but is preferably set to 0.2 V or more from the viewpoint of protecting the solid polymer electrolyte membrane 21. Therefore, the second predetermined pressure is set to a value lower than the voltage in normal operation and higher than the first predetermined pressure.

  The behavior after the shift to the increased supply control is the same control method as in the control pattern 1.

<< Control pattern 5 >>
The fuel control mechanism 33 includes means for detecting a current value of the power generation state of the power generation unit 2, and when the current of the power generation unit 2 exceeds a predetermined value, the fuel control mechanism 33 performs normal operation. Shift from control to decrease control. Since the current during normal power generation of the power generation unit 2 depends on the size of the power generation effective area determined by the solid polymer electrolyte membrane 21, the oxidant electrode 22, and the fuel electrode 23, the size cannot be generally described. As shown in control pattern 4, it is desirable that the current value corresponds to a voltage value in the vicinity of 0.7 V during normal operation. The normal operation is continued, and the voltage value decreases due to an increase in diffusion overvoltage caused by impurities covering the fuel electrode 23. Since power is given by the product of voltage and current, when the above-mentioned voltage drop occurs when the required power of the equipment used is constant, the current value increases accordingly. Similarly to the control pattern 4, when the current value corresponding to the second predetermined value is reached, the shift from the normal operation to the reduced supply control is completed, and when the current value corresponding to the first predetermined value is reached, the reduction supply control is terminated. Shift to increased supply control.

The behavior after the shift to the increased supply control is the same control method as in the control pattern 2.
<< Control pattern 6 >>
The fuel control mechanism 33 is provided with means for detecting the power generation time of the power generation unit 2, and when the power generation time of the power generation unit 2 has passed a predetermined time, the fuel control mechanism 33 is controlled to decrease from normal operation control. Migrate to The time during which impurities accumulate in the fuel electrode portion 26 and the return operation is required is set in advance, and the fuel control mechanism 33 receives the power generation time information of the power generation portion 2 to cover the surface of the fuel electrode portion 23 with impurities. And shift from normal operation to reduced supply control. The switching from the decrease supply control to the increase supply control is preferably performed while the fuel pressure necessary for power generation remains in the fuel electrode in order to prevent deterioration of the membrane electrode assembly. Since the amount of fuel generated in the reduction supply control is known, the time after the shift to the reduction supply control, the amount of fuel used in power generation, and the internal volume of the fuel electrode portion 26 are used. The remaining amount of fuel can be calculated. Therefore, the shift to the increase supply control is performed before the fuel in the fuel electrode 26 is completely consumed by the decrease supply control.

  The behavior after the shift to the increased supply control is the same control method as in the control pattern 3.

Although applicable to all control patterns, the timing for ending the reduction supply control may be controlled by the pressure value. The fuel control mechanism 33 is provided with means for detecting the fuel pressure of the fuel electrode part 26, and when the fuel pressure of the fuel electrode part 26 becomes equal to or higher than a predetermined value after the stop control is started, the fuel control mechanism 33. Shift from decreasing supply control to increasing supply control. The predetermined pressure may be lower than the internal pressure of the fuel electrode portion 26 in normal operation, but it is better to set the pressure to 40 kPa or more in order to avoid excessive fuel shortage of impurities in the fuel electrode portion 26. .
Note that, similarly to the control patterns 1 to 3, switching of the control state may be performed by different triggers.

According to the configuration and the control method of the fuel cell 1 shown in the present embodiment, the fuel is supplied to the fuel supply space 25 at a higher speed than the normal operation for a longer time, and thus covers the fuel electrode 23. Impurities can be removed more efficiently.
(Embodiment 3)
FIG. 6 shows a schematic configuration diagram of the fuel cell 1 according to Embodiment 3 of the present invention. The same parts as those in the first or second embodiment are denoted by the same reference numerals, and description of similar configurations and operations is omitted. Hereinafter, the fourth embodiment will be described with reference to FIG.

  In the fuel cell 1 according to Embodiment 4 of the present invention, a fuel valve 35 is provided between the power generation unit 2 and the fuel supply source 3 in the fuel cell 1 according to Embodiment 1 or 3. The fuel valve 35 has an open state in which the fuel can be moved from the fuel supply source 3 to the power generation unit 2 and a closed state in which the fuel cannot be moved depending on the open / close state of the valve body. The opening / closing operation operates in conjunction with the control of the fuel control mechanism 33. Further, the place where the fuel valve 35 is provided may be anywhere between the inlet of the fuel supply space 25 and the outlet of the fuel supply source 3, and as shown in FIG. May be provided in the fuel supply path 34 when they are connected to each other by the fuel supply path 34.

  When the fuel cell 1 is generating electric power during normal operation, the fuel valve 35 is open. If the power generation unit 2 continues to generate power in this state, impurities accumulate in the fuel electrode portion 26 and the fuel electrode 23 is covered, so that the diffusion overvoltage increases and the power generation voltage of the power generation unit 2 decreases. The fuel control mechanism 33 shifts to reduction supply control when impurities accumulate in the fuel electrode portion 26 at a predetermined amount or more. At this time, the fuel valve 35 also shifts to the closed state. The internal space of the supply source 3 is blocked. Since the power generation unit 2 generates power in this state, the pressure of the gas containing the fuel in the fuel supply space 25 decreases, while the fuel supply source 3 does not supply fuel to the power generation unit 2 and supplies fuel. The internal pressure of the source 3 is maintained or rises slowly. And when the voltage of the electric power generation part 2 falls to a predetermined value and the fuel control mechanism 33 complete | finishes 1st control, the fuel valve 35 will transfer to an open state. At this time, since the pressure difference is generated in the internal space between the power generation unit 2 and the fuel supply source 3 as described above, the fuel flows into the fuel supply unit 25 vigorously when the fuel valve 35 is opened. To do. For this reason, the impurities covering the fuel electrode 23 are easily blown away by the fuel.

  The opening / closing operation of the fuel valve 35 may be controlled by the user of the fuel cell 1, but the fuel valve 35 is linked with the fuel control mechanism 33 as shown in FIG. It is good to be a solenoid valve that opens and closes in response to a signal related to control information 33.

  The fuel supply source 3 is detachable so that another fuel supply source 3 containing the fuel precursor 32 can be used when the remaining amount of the fuel precursor 32 in the interior is exhausted and fuel cannot be supplied to the power generation unit 2. A cartridge structure may be used. In that case, the fuel valve 35 is preferably provided on the power generation unit 2 side when the power generation unit 2 and the fuel supply source 3 are separated. With such a configuration, it is not necessary to provide an extra mechanism for the fuel supply source 3 that is an exchange member, so that the manufacturing cost of the fuel supply source 3 can be kept low. In addition, when the power generation unit 2 and the fuel supply source 3 are separated, it is possible to prevent fuel leakage if a valve function is provided to block the flow path cross section of the separated part. You may have.

According to the present embodiment, since a pressure difference is obtained between the power generation unit 2 and the fuel supply source 3 by the fuel valve 35, the fuel supply speed to the fuel supply space 25 in the return operation is increased, and impurities are further removed. It can be done reliably.
(Embodiment 4)
A schematic diagram of a fuel cell 1 according to Embodiment 4 of the present invention is shown in FIG. The same parts as those in the first to third embodiments are denoted by the same reference numerals, and the description of the same configuration and operation is omitted. Hereinafter, the fourth embodiment will be described with reference to FIG.

  As shown in FIG. 7, in addition to the fuel cell 1 in the fourth embodiment, the fuel cell 1 in the fifth embodiment of the present invention includes a discharge part 4 connected to the fuel electrode part 26, a fuel electrode part 26 and a discharge part 4. A discharge valve 41 is provided between the two.

  The discharge part 4 is connected to the fuel supply space 25 of the fuel electrode part 26, and impurities accumulated in the fuel supply space 25 can move to the discharge part 4. In the power generation unit 2 in this configuration, since the internal volume of the fuel electrode part 26 is expanded by the discharge part 4, when the fuel control mechanism 33 is changed from the reduced supply control to the normal operation state, the internal pressure of the fuel in the fuel electrode part 26 is increased. It is necessary to supply more fuel until the pressure rises to the same level as that used during normal operation. For this reason, the supply of fuel to the fuel supply space 25 can be continued for a longer time. In the first to fourth embodiments, when the return operation is performed, the impurities remain in the fuel supply space 25. Therefore, even if the return operation is performed a plurality of times and the amount of impurities accumulated in the fuel supply space 25 increases, Although there is no place to go, in the fifth embodiment, the discharge unit 4 is provided at a location different from the fuel supply space 25, and the impurities move to the discharge unit 4 so that more return operations can be performed. I can do it.

  In order to move impurities to the discharge part 4 more reliably, the discharge part 4 is provided at a location away from the fuel control mechanism 33 in the fuel supply space 25, that is, downstream of the hydrogen flow. desirable. When there is a distance between the power generation unit 2 and the discharge unit 4, both components may be connected by a discharge path 42 such as a pipe or a tube.

  Moreover, it is further preferable that the discharge unit 4 is configured to be removable. In such a configuration, when the impurities are fully accumulated in the discharge unit 4, the discharge unit 4 is detached from the power generation unit 2, and after the impurities accumulated in the discharge unit 4 are discarded, the power generation unit again By attaching to 2, it becomes possible to perform the return operation repeatedly. In that case, it is preferable that a discharge unit 41 is provided on the power generation unit 2 side between the discharge unit 4 and the fuel supply space 25. As shown in FIG. 5, the discharge unit 41 may be on the discharge path 42 or may be provided in the power generation unit 2. The discharge part 41 is a valve body that takes one of an open state in which the impurities inside the fuel electrode part 26 are discharged to the discharge part 4 and a closed state in which the impurities inside the fuel electrode part 26 are not discharged to the discharge part 4. is there. During normal operation including the return operation, the discharge part 41 is in an open state, and when the discharge part 4 is removed, the discharge part 41 is closed so that fuel from the connection flow path between the fuel supply space 25 and the discharge part 4 can be obtained. It becomes possible to prevent leakage.

  Further, as shown in FIG. 7, the discharge unit 4 may be provided in the same exchanger as the fuel supply source 3. In such a configuration, when the fuel supply source 3 has a cartridge structure, the remaining amount of the fuel precursor 32 in the exchange body disappears and is replaced with a new exchange body. The discharge unit 4 can be replaced with a new one at an appropriate timing not satisfying.

According to the present embodiment, the impurities in the fuel electrode portion 26 can be more reliably removed by the return operation, and the return operation can be performed more times by the impurities moving to the discharge portion 4. is there.
(Embodiment 5)
FIG. 8 shows an enlarged cross-sectional view of the fuel electrode portion 26 of the power generation unit 2 according to Embodiment 5 of the present invention. The same parts as those in Embodiments 1 to 4 are denoted by the same reference numerals, and description of similar configurations and operations is omitted. Hereinafter, the fifth embodiment will be described with reference to FIG.

  As shown in FIG. 8, the power generation unit 2 according to the sixth embodiment of the present invention has a fuel flow path 261 in the fuel electrode portion 26 in addition to the power generation unit 2 according to the first to fifth embodiments. The fuel supplied from the fuel supply source 3 reaches the fuel electrode 23 through the fuel flow path 261 provided inside the fuel electrode portion 26. The fuel flow path 261 is provided so as to supply fuel vertically to the fuel electrode 23. As a result, the fuel is directly sprayed onto the fuel electrode 23, so that impurities covering the fuel electrode 23 can be removed more reliably.

  Further, FIG. 9 shows an enlarged cross-sectional view of the fuel electrode portion 26 of the power generation unit 2 according to the modification of the fifth embodiment. As shown in FIG. 9, the power generation unit 2 in the present modification includes a plurality of fuel flow paths 261. In particular, when the area of the fuel electrode 23 is large, it is difficult to remove impurities covering the entire catalyst layer 231 with a single fuel flow path 261 as shown in FIG. Therefore, by providing a plurality of fuel flow paths 261 with respect to the surface of the fuel electrode 23 as shown in FIG. 9, even if impurities exist so as to cover the entire catalyst layer 23 having a large area, the impurities are removed. It is possible to remove it reliably. Further, in order to hold the plurality of fuel flow paths 261 and distribute the fuel to the plurality of fuel flow paths 261, it is desirable to provide a partition wall 262 so that the fuel electrode portion 26 is separated into two layers. By providing the partition wall 262, the fuel passes from the fuel supply source 3 through the fuel control mechanism 33 to the distribution space 251 separated from the fuel supply space 25 by the partition wall 262, and then from the plurality of fuel flow paths 261 to the fuel electrode 23. Supplied.

  Further, a diffusion portion 263 may be provided in order to further expand the removal range of impurities covering the fuel electrode 23 of one fuel flow path 261. The diffusion portion 263 is a member that extends from a position in contact with the fuel electrode 23 of the fuel flow path 261 along the surface direction of the fuel electrode 23. By providing the diffusion part 263 further, the fuel that has passed through the fuel flow path 261 is supplied to the fuel supply space 25 through the fuel electrode 23 between the diffusion part 263 and the solid polymer electrolyte membrane 21. The impurities covering the fuel electrode 23 in the range where the diffusion portion 263 is provided can be reliably moved to a part of the fuel supply space 25.

According to the present embodiment, the removal of impurities covering the fuel electrode 23 by the return operation can be performed more reliably in a wide range.
(Embodiment 6)
FIG. 10 shows an exploded perspective view of the fuel electrode portion 26 of the power generation unit 2 according to Embodiment 6 of the present invention. The same parts as those in the first to fifth embodiments are denoted by the same reference numerals, and the description of the same configuration and operation is omitted. Hereinafter, the sixth embodiment will be described with reference to FIG.

  In addition to the fuel electrode portion 26 of the power generation section 2 in the fifth embodiment, the power generation section 2 in the sixth embodiment of the present invention is provided with a fuel supply space 25 in a groove shape with respect to the outer wall 24 as shown in FIG. ing. The fuel supply space 25 is arranged to meander and the fuel spreads over the entire surface of the fuel electrode 23. The base surface 252 in which the groove of the fuel supply space 25 is cut is in contact with the fuel electrode 23, and the outer wall 24 is preferably made of a conductive material such as metal represented by stainless steel or carbon. If it is the said structure, since it can collect electric current from the whole surface of the fuel electrode 23 and an electrical resistance becomes low, it is possible to perform more efficient electric power generation.

  In addition, through holes connected to the outside of the fuel electrode portion 26 are provided at both ends of the fuel supply space 25. One of the through holes is a supply port 253 for taking the fuel supplied from the fuel supply source 3 into the fuel supply space 25, and the other is a discharge port 254 connected to the discharge unit 4.

  Even when power generation is continued at the fuel electrode portion 26 in the present embodiment, impurities are accumulated in the fuel supply space 25 and the supply of the fuel 3 to the catalyst layer 231 is obstructed. However, the fuel supply space 25 is grooved and has impurities. Since the conducting flow path is secured, the impurities can be more reliably moved to the discharge section 4 by performing the return operation.

  Although an example of the present invention has been described above, only a specific example has been described. The present invention is not particularly limited, and the specific configuration and the like of each part can be changed as appropriate. In addition, the operation and effect of each embodiment and the modification only enumerate the most preferable operation and effect resulting from the present invention, and the operation and the effect of the present invention are described in each embodiment and modification. It is not limited to things. Further, in the specification, for convenience of explanation, the fuel cell is constituted by a single cell, but the present invention can also be applied to a fuel cell having a structure having a plurality of power generation cells sandwiched between supports.

  The present invention can be used in the industrial field of fuel cells and fuel cell devices.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Power generation part 3 Fuel supply source 4 Discharge part 21 Solid polymer electrolyte membrane 22 Oxidant electrode 23 Fuel electrode 24 Outer wall 25 Fuel supply space 26 Fuel electrode part 31 Reaction part 32 Fuel precursor 33 Fuel control mechanism 34 Supply path 35 Fuel valve 36 Signal line 41 Discharge valve 42 Discharge path 221 Catalyst layer (oxidant electrode)
222 Gas diffusion layer (oxidizer electrode)
231 Catalyst layer (fuel electrode)
232 Gas diffusion layer (fuel electrode)
251 Distribution space 252 Base surface 253 Supply port 254 Discharge port 261 Fuel flow path 262 Partition

Claims (13)

A power generation unit including a fuel electrode supplied with fuel, an oxidant electrode supplied with an oxidant, and a solid polymer electrolyte membrane sandwiched between the fuel electrode and the oxidant electrode;
A fuel electrode part having a fuel supply space provided in the power generation part so as to be opposed to a surface of the fuel electrode on which the electrolyte membrane is disposed;
A fuel supply source that generates a fuel by contacting a plurality of fuel precursors to perform a chemical reaction, and supplies the fuel to the fuel electrode portion;
The fuel supply source is:
A plurality of reservoirs each storing a plurality of fuel precursors;
A fuel control mechanism that moves the fuel precursor stored in at least one of the plurality of fuel precursors to the other storage unit, and
The fuel control mechanism performs supply control for controlling movement of the fuel precursor based on a physical quantity related to impurities accumulated in the fuel electrode due to a reaction between the fuel and the oxidant,
At least a part of the impurities is removed by the pressure of the fuel generated by the supply control. The fuel control mechanism includes a physical quantity detection unit that detects a physical quantity related to the impurities,
When the physical quantity detection unit detects the physical quantity indicating that the impurity has accumulated a predetermined amount or more in the fuel electrode, the physical quantity detection unit performs an increase supply control for increasing the movement of the fuel precursor as compared with that during normal operation. The fuel cell according to claim 1. The fuel control mechanism includes a physical quantity detection unit that detects a physical quantity related to the impurities,
A decrease supply control for reducing movement of the fuel precursor when the physical quantity detection unit detects the physical quantity indicating that the impurity has accumulated a predetermined amount or more in the fuel electrode; and the fuel after the decrease supply control. The fuel cell according to claim 2, wherein an increase supply control for increasing the movement of the precursor is performed. Between the fuel supply source and the power generation unit, there is provided a fuel valve that maintains either an open state in which the fuel is supplied to the fuel electrode part or a closed state in which the fuel is not supplied to the fuel electrode part. Prepared,
The fuel cell according to claim 3, wherein the fuel valve is in the closed state when performing a decrease supply control.   5. The fuel cell according to claim 1, wherein the fuel electrode part is connected to a discharge part that discharges impurities inside the fuel electrode part. 6. The fuel electrode part and the discharge part are detachable,
Between the fuel electrode portion and the discharge portion, an open state in which impurities inside the fuel electrode portion are discharged to the discharge portion, and a closed state in which impurities inside the fuel electrode portion are not discharged to the discharge portion With a discharge valve that maintains either
The fuel cell according to claim 5, wherein the discharge valve is provided in the fuel electrode portion.   The fuel cell according to any one of claims 1 to 6, wherein the fuel electrode portion includes a fuel flow path in which the fuel is supplied in a direction perpendicular to a surface direction of the fuel electrode.   The fuel cell according to claim 7, wherein the fuel flow path includes a diffusion portion that diffuses the fuel in a surface direction of the fuel electrode.   The fuel cell according to claim 5, wherein the fuel supply space is a groove provided for the fuel electrode.   The fuel according to any one of claims 2 to 9, wherein the physical quantity is a voltage value of the power generation unit, and the physical quantity detection unit detects a state in which the voltage value is equal to or less than a predetermined value. battery.   The fuel according to any one of claims 2 to 9, wherein the physical quantity is a current value of the power generation unit, and the physical quantity detection unit detects a state where the current value is equal to or greater than a predetermined value. battery.   10. The physical quantity is a time after the fuel cell starts power generation, and the physical quantity detection unit detects a state in which the predetermined time has elapsed. The fuel cell as described.   The fuel cell according to any one of claims 4 to 12, wherein the storage unit and the discharge unit have a cartridge structure that is detachable from the power generation unit.

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