JP6565758B2 - FUEL CELL, FUEL CELL CONTROL METHOD, AND COMPUTER PROGRAM - Google Patents

Description

  The present invention relates to a fuel cell and a fuel cell including a power generation unit that reacts with hydrogen and oxygen to generate power, a drain valve that discharges water discharged from the power generation unit to the outside, and a control unit that controls opening and closing of the drain valve And a computer program for causing a computer to execute wastewater treatment.

Examples of the battery for obtaining electromotive force by sending hydrogen to the negative electrode include a fuel cell and a nickel / hydrogen battery.
A fuel cell is a clean power generator with high power generation efficiency, and can be constructed without being affected by the magnitude of the load, so it can be used in digital home appliances such as personal computers and mobile phones, electric cars, railways, and mobile phones. Various uses such as base stations and power plants are being studied.

The fuel cell includes a stack, a plurality of hydrogen cylinders, a hydrogen circulation path, and a hydrogen supply path.
The stack forms a membrane electrode assembly by sandwiching the solid polymer electrolyte membrane between the negative electrode and the positive electrode from both sides, and configures a flat unit cell by arranging a pair of separators on both sides of the membrane electrode assembly, A plurality of unit cells are stacked and packaged.

One end of the hydrogen supply path is connected to a hydrogen cylinder through a regulator and an on-off valve. Hydrogen is flowed from the hydrogen cylinder through the hydrogen supply path, is sent to the negative electrode side portion in the stack through the portion near the negative electrode of the stack in the hydrogen circulation path, and is passed through the flow path in the portion. Exhaust gas (off-gas) containing unreacted hydrogen flowing through the flow path and discharged from the stack flows through the hydrogen circulation path and is returned to the stack.
Hydrogen is supplied to the stack, a fuel gas containing hydrogen is brought into contact with the negative electrode, and an oxidizing gas containing oxygen such as air is brought into contact with the positive electrode, whereby an electrochemical reaction occurs in both electrodes, and an electromotive force is generated. During the reaction, water is generated on the positive electrode side, and this water is back-diffused through the electrolyte membrane to the negative electrode side as water vapor. Water vapor or water condensed due to temperature is included in the off-gas.

  As described above, since moisture is contained in the off-gas, a gas-liquid separator is provided in the hydrogen circulation path to separate the gas and water, the gas is returned to the stack, and the stored water is discharged in a timely manner. I am doing so.

When the power generation of the fuel cell is stopped, water is collected in the gas-liquid separator, but water freezes in an environment below freezing point. For this reason, it becomes impossible to drain at the next power generation. As a result, the fuel cell enters a flooding state where water overflows and blocks the hydrogen circulation path, and the function is reduced.
Therefore, it is necessary to prevent freezing by preventing water from remaining in the gas-liquid separator when power generation of the fuel cell is stopped.

  In Patent Document 1, water generated by power generation is guided and stored in a storage section provided below the hydrogen circulation path, the water level of the storage section is detected by a water level sensor, and the upper limit water level set in advance by the water level is set. An invention of a fuel cell configured to discharge the generated water of the storage part from the lower part when exceeded is disclosed.

JP 2002-313403 A

  When the water level is monitored by the water level sensor and drained as in the fuel cell according to Patent Document 1, when the water level is at a position detected by the water level sensor, the water level can be drained, but the position where the water level is not detected by the water level sensor In this case, the entire water stored in the gas-liquid separator cannot be discharged. If water remains in the gas-liquid separator, it will freeze in a sub-freezing environment as described above.

  The present invention has been made in view of such circumstances, suppresses the residual water in the gas-liquid separator when power generation is stopped, prevents freezing, and can perform good drainage during the next power generation, It is an object of the present invention to provide a fuel cell, a fuel cell control method, and a computer program in which deterioration of the fuel cell function is prevented.

  A fuel cell according to the present invention includes a power generation unit that generates electricity by reacting hydrogen and oxygen, a fuel unit that supplies hydrogen to the power generation unit, an on-off valve for supplying the hydrogen, and an exhaust from the power generation unit. A hydrogen circulation path that circulates the generated gas back to the power generation unit, a gas-liquid separator that is provided in the hydrogen circulation path and separates water from the gas, and a drain valve that discharges water from the gas-liquid separator; A pressure detector for detecting a gas pressure in the hydrogen circulation path and in the gas-liquid separator, and a pressure detector for controlling the opening and closing of the on-off valve and the drain valve. A measuring unit that measures a time when the pressure obtained from a predetermined amount changes, and the control unit controls opening and closing of the on-off valve and the drain valve based on the time measured by the measuring unit. It is characterized by performing wastewater treatment.

  In the fuel cell control method according to the present invention, the on-off valve is opened to supply hydrogen from the fuel unit to the power generation unit, and the gas exhausted from the power generation unit is circulated back to the power generation unit through a hydrogen circulation path. In a control method of a fuel cell in which water is separated from the gas by a gas-liquid separator provided in a hydrogen circulation path and drainage treatment is performed by a drain valve, in the first drainage treatment, in the hydrogen circulation path and the gas-liquid The time until the first pressure of the gas in the separator is reduced to the second pressure is acquired, and the number of wastewater treatments is calculated based on the first pressure, the second pressure, and the time, and is calculated The waste water treatment is performed by controlling the opening and closing of the on-off valve and the drain valve for the number of times.

  A computer program according to the present invention is a computer that controls a fuel cell including a hydrogen circulation path that returns and circulates gas exhausted from a power generation unit, and a gas-liquid separator that separates and drains water from the gas. In the waste water treatment for the second time, the time until the first pressure of the gas in the hydrogen circulation path and the gas-liquid separator is reduced to the second pressure is acquired, and the first pressure, the second pressure, and the The number of times of waste water treatment is calculated based on the time, and processing for outputting an on / off signal for the on / off valve for supplying hydrogen and an on / off signal for the drain valve is executed according to the calculated number of times.

According to the present invention, the gas in the hydrogen circulation path is increased based on the pressure difference when the on-off valve is opened and the drain valve is closed, and then the on-off valve is closed and the drain valve is opened to open the hydrogen circuit. By measuring the time when the gas pressure in the hydrogen circulation path and the gas-liquid separator changes by a predetermined amount when water stored in the gas-liquid separator is pushed out and drained, the next time The drainage time can be estimated, drainage can be performed well so as to suppress the remaining water in the gas-liquid separator, and freezing can be prevented. Therefore, drainage can be performed satisfactorily at the next power generation, and the deterioration of the fuel cell function is prevented.
In the drainage treatment, drainage is performed with the open / close valve closed, so that even if the drainage valve breaks down, leakage of more than a prescribed amount of hydrogen is prevented.

It is a block diagram which shows the fuel cell which concerns on embodiment. It is a flowchart of the main routine which shows the procedure of the waste_water | drain process by CPU. It is a flowchart of the subroutine which shows the procedure of the 1st drainage process. It is a flowchart of the subroutine which shows the procedure of the waste water treatment after the 2nd time. It is a typical sectional view of a gas liquid separator. It is a schematic diagram for visualizing and explaining the waste water treatment of Calculation Example 1. It is a schematic diagram for visualizing and explaining the waste water treatment of Calculation Example 2.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a block diagram showing a fuel cell 300 according to an embodiment.
The fuel cell 300 includes a battery body 100 and a hydrogen supply unit 200. The battery body 100 is a battery body such as a polymer electrolyte fuel cell.
The battery body 100 includes a stack 1, an air flow path 3, an air pump 30, a stack cooling path 4, a cooling pump 40, a first heat exchanger 41, a second heat exchanger 42, a radiator flow path 5, a heat dissipation pump 50, and a radiator. 51, fan 52, cylinder heating path 6, heating pump 60, hydrogen flow path 7, first pressure sensor 78, on-off valves 79, 80, hydrogen circulation pump 82, gas-liquid separator 83, drain valves 84, 85, exhaust Valves 86 and 87, a second pressure sensor 88, and a control unit 9 are provided. The second heat exchanger 42 includes a heater (not shown).

  The hydrogen supply unit 200 includes a plurality of MH (Metal Hydride) cylinders 20, an on-off valve 21, and a regulator 22. The MH cylinder 20 is filled with a hydrogen storage alloy. All the MH cylinders 20 are connected to the on-off valve 21, and the on-off valve 21 is connected to a regulator 22. The supply pressure of hydrogen is adjusted by the regulator 22. The reaction when the hydrogen storage alloy in the MH cylinder 20 releases hydrogen is an endothermic reaction.

In the stack 1, a membrane electrode assembly is formed by sandwiching a solid polymer electrolyte membrane between a negative electrode and a positive electrode from both sides, and a pair of separators are arranged on both sides of the membrane electrode assembly to constitute a flat unit cell. A plurality of unit cells are stacked and packaged.
A fuel gas containing hydrogen flowing in from the hydrogen supply unit 200 comes into contact with the negative electrode, and an oxidizing gas containing oxygen such as air flows into and comes into contact with the positive electrode from the air flow path 3 to cause an electrochemical reaction in both electrodes. Electromotive force is generated and water is generated.

  The hydrogen flow path 7 includes a hydrogen supply path 71, a hydrogen introduction path 72, a hydrogen circuit 73, a first drainage path 74, and a first exhaust path 75. A hydrogen circulation path is constituted by the hydrogen introduction path 72, the hydrogen circuit 73, and the first exhaust path 75. One end of the hydrogen supply path 71 is connected to the regulator 22, and the on-off valves 79 and 80 are connected in series to the other end. The hydrogen introduction path 72 has one end connected to the on-off valve 80 and the other end connected to a portion of the stack 1 near the negative electrode. A first pressure sensor 78 and a check valve 81 are provided in the hydrogen introduction path 72.

The hydrogen circuit 73 is provided with a hydrogen circulation pump 82 and a gas-liquid separator 83. When the on-off valves 21, 79, 80 are opened, hydrogen flows through the hydrogen supply path 71 and the hydrogen introduction path 72, flows through the hydrogen circuit 73 by the hydrogen circulation pump 82, and is sent to the negative electrode side portion of the stack 1. , It is configured to flow through the flow path in the portion. Hydrogen, impurities (including impurities originally contained in hydrogen and impurities generated by the reaction), and water flowing through the flow path and discharged from the stack 1 flow through the hydrogen circuit 73 to be gas-liquid. It is sent to the separator 83.
In the gas-liquid separator 83, the gas and water containing hydrogen and impurities are separated into water.

  The first drainage channel 74 is connected to the lower side of the gas-liquid separator 83, and drainage valves 84 and 85 that are electromagnetic valves are provided in series in the first drainage channel 74. A second drainage channel 76 is connected to the drainage valve 85.

  The first exhaust passage 75 is provided on the upper side of the gas-liquid separator 83 so as to branch off from the hydrogen circuit 73, and the first exhaust passage 75 has exhaust valves 86 and 87 for discharging the gas. It is provided in series. The gas flows through the second exhaust passage 77 by passing through the exhaust valves 86 and 87 and opening them at a predetermined timing, and is discharged to the outside.

  In the gas-liquid separator 83, when the exhaust valves 86 and 87 are closed, the separated gas flows from the gas-liquid separator 83 through the hydrogen circuit 73 to the hydrogen circulation pump 82 and is returned to the stack 1. .

The water separated by the gas-liquid separator 83 is stored, and flows through the first drainage channel 74 and the second drainage channel 76 by energizing and opening the drainage valves 84 and 85 by drainage treatment described later, and to the outside. Discharged.
The second pressure sensor 88 is provided below the gas-liquid separator 83.

  The drain valves 84 and 85 and the exhaust valves 86 and 87, and the first drain path 74 and the first exhaust path 75 may be covered with a heat insulating material.

  An air pump 30 is provided in the air flow path 3. An opening / closing valve 31 is provided at the inflow side portion of the air flow path 3 to the stack 1, and an opening / closing valve 32 is provided at the outflow side portion from the stack 1. When the on-off valve 31 and the on-off valve 32 are opened, the air sent from the air pump 30 flows through the air flow path 3 and is introduced into the positive electrode side portion of the stack 1 so as to flow through the flow path of the portion. It is configured. The air flowing through the flow path is discharged from the stack 1 and discharged to the outside through the on-off valve 32.

  In the stack cooling path 4, a cooling pump 40, an ion exchange resin 43, and a conductivity meter 44 are provided. Cooling water sent from the cooling pump 40 and flowing through the stack cooling path 4 flows through the ion exchange resin 43, and the conductivity is measured by the conductivity meter 44, and then introduced into the stack 1. After flowing through the flow path, the flow is discharged, passed through the first heat exchanger 41 and the second heat exchanger 42, and returned to the cooling pump 40.

  A radiator pump 50 is provided in the radiator passage 5. The heat-dissipating liquid such as antifreeze liquid sent from the heat-dissipating pump 50 flows through the radiator 51, further flows through the first heat exchanger 41, and then returns to the heat-dissipating pump 50. A fan 52 is provided in the vicinity of the radiator 51.

  A heating pump 60 is provided in the cylinder heating path 6. The heating liquid sent from the heat pump 60 flows through the flow path in the hydrogen supply unit 200 to heat each MH cylinder 20, and then is discharged from the hydrogen supply unit 200 and flows through the second heat exchanger 42. Thus, it is configured to return to the heating pump 60. By heating, hydrogen is released from the hydrogen storage alloy in the MH cylinder 20. An antifreeze can be used as the heating liquid.

  The stack cooling path 4, the radiator passage 5, the cylinder heating path 6, the first heat exchanger 41, and the second heat exchanger 42 are covered with a heat insulating material. The portion covered with the heat insulating material is represented by a thick line in FIG. With this heat insulating material, heat transfer with the outside can be limited, and the amount of heat can be easily controlled.

  The control unit 9 includes a CPU (Central Processing Unit) 90 that controls the operation of each component of the control unit 9, and a ROM 91, a RAM 92, and a timer 93 are connected to the CPU 90 via a bus.

The ROM 91 is a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable ROM), and stores an operation program 91a of the fuel cell 300 and a drainage control program 91b according to the present embodiment.
Also, the drainage control program 91b is a portable media recorded in a computer-readable manner such as a CD (Compact Disc) -ROM, a DVD (Digital Versatile Disc) -ROM, a BD (Blu-ray (registered trademark) Disc), a hard disk. It is recorded on a recording medium such as a drive or a solid state drive, and the CPU 91 may read out the drainage control program 91b from the recording medium and store it in the ROM 91.
Furthermore, the drainage control program 91b according to the present invention may be acquired from an external computer (not shown) connected to the communication network and stored in the ROM 91.

The RAM 92 is a memory such as DRAM (Dynamic RAM), SRAM (Static RAM), and the like, and is executed by the operation program 91a, the drainage control program 91b, and the CPU 90 read out from the ROM 90 when the CPU 91 executes the operation processing. Temporarily store various data generated.
The control unit 9 is connected to each component of the battery main body 100 and the on-off valve 21 of the hydrogen supply unit 200, and the control unit 9 controls the operation of each component and the on-off valve 21. The controller 9 is connected to the first pressure sensor 78 and the second pressure sensor 88. In FIG. 1, the connection between the control unit 9 and each component is shown only in the part necessary for the description of the present embodiment.

  The reaction occurring in the stack 1 is an exothermic reaction, and the stack 1 is cooled by cooling water flowing through the stack cooling path 4. The heat of the cooling water discharged from the stack 1 is conducted to the heat radiating liquid in the first heat exchanger 41, the heat radiating liquid releases heat in the radiator 51, and the heat is released to the outside of the battery body 100 by the fan 52. . The radiator liquid cooled in the radiator 51 is sent to the first heat exchanger 41.

In the stack cooling path 4, the heat of the cooling water flowing through the first heat exchanger 41 and introduced into the second heat exchanger 42 is conducted to the heating liquid in the second heat exchanger 42, and the heating liquid is supplied with hydrogen. Each MH cylinder 20 of the unit 200 is heated to release hydrogen from the hydrogen storage alloy.
The cooling water cooled by the second heat exchanger 42 returns to the cooling pump 40 and is sent to the stack 1.
When power generation is not being performed, the temperature of the cooling water in the stack cooling path 4 becomes the environmental temperature. By heating the heating liquid with the heater of the second heat exchanger 42, the MH cylinder 20 is kept at a predetermined temperature. Can be held in.
Instead of having the cylinder heating path 6, the MH cylinder 20 may be heated by blowing air having heat generated in the stack 1 to the hydrogen supply unit 200. Alternatively, a heater may be provided in the MH cylinder 20 and the MH cylinder 20 may be directly heated by the heater.

In the present embodiment, the CPU 90 of the control unit 9 reads the drainage control program 91b from the ROM 91 after the power generation is completed, and executes the drainage process of the gas-liquid separator 83.
Hereinafter, this waste water treatment will be described.

FIG. 2 is a flowchart of the main routine showing the procedure of the wastewater treatment by the CPU 90.
The initial condition is when the battery main body 100 is generating power, and the on-off valves 21, 79, and 80 are energized on (open), and the drain valves 84 and 85 are energized off (closed).
From this state, the CPU 90 stops power generation and starts drainage treatment.

First, the CPU 90 sets the number j of wastewater treatment to “1” (S1).
CPU90 performs first waste water treatment, measuring the drainage time t ₁ (S2).

Hereinafter, the procedure of the first drainage process in step S2 will be described with reference to the subroutine flowchart shown in FIG.
The CPU 90 sequentially outputs a close signal to the on-off valves 21, 79, 80 and turns them off (S11, S12, S13).
The CPU 90 acquires PH from the first pressure sensor 78 (S14) and stores it in the RAM 92. Next, the CPU 90 acquires P0 from the second pressure sensor 88 (S15) and stores it in the RAM 92. Here, PH is the pressure of the gas in the hydrogen circulation path and the gas-liquid separator 83, and P0 is the external pressure.

The CPU 90 sequentially outputs an open signal to the drain valves 84 and 85 to turn them on (S16, S17), and starts draining. Next, the CPU 90 starts measuring the drain time t ₁ by the timer 93 (S18).

PH gradually decreases as drainage proceeds. CPU90 determines whether PH acquired from the 1st pressure sensor 78 is larger than P0 (S19). When the CPU 90 determines that PH is greater than P0 (S19: YES), the above determination is repeated.
When the CPU 90 determines that PH is not greater than P0 (S19: NO), that is, when PH reaches the same pressure as P0, drainage cannot be performed, so drainage ends, and the process proceeds to step S20. CPU90 terminates the measurement of the drainage time t ₁ by the timer 93 (S20), and stores the drainage time t ₁ measured in RAM 92 (S21). This completes the first drainage process and returns to the main routine shown in FIG.

The CPU90, after first waste water treatment in step S2, step S14, PH, which has been stored acquired in RAM92 in S15 P0, and on the basis of the drainage time t _1, calculating the set number n of the waste water treatment The set number n is stored in the RAM 92 (S3). A method of calculating the set number n will be described later.

CPU90 determines whether the frequency | count j of drainage is the setting frequency n (S4).
When the CPU 90 determines that the number of times j of drainage is not the set number n (S4: NO), the CPU 90 performs the second and subsequent drainage processing (S5).

Hereinafter, the second and subsequent drainage processing procedures in step S5 will be described with reference to the flowchart of the subroutine shown in FIG.
The CPU 90 sequentially outputs a close signal to the drain valves 85 and 84 and turns off (S31, S32). Next, the CPU 90 sequentially outputs an open signal to the on-off valves 80, 79, 21 and turns them on (S33, S34, S35). As a result, hydrogen is supplied from the hydrogen supply unit 200 into the hydrogen circulation path, and the pressure of the gas in the hydrogen circulation path and the gas-liquid separator 83 rises to the same PH as the pressure value acquired in step S14. . Here, the time T ₀ required for the gas pressure in the hydrogen circulation path and the gas-liquid separator 83 to rise from P0 to PH is calculated in advance based on the flow rate of hydrogen supplied from the hydrogen supply unit 200. Is set. The CPU 90 determines whether or not the time T ₀ has elapsed (S36). When it is determined that the time T ₀ has not elapsed (S36: NO), the CPU 90 repeats the above determination.
Further, the CPU 90 may confirm whether or not the gas pressure has increased to the PH value acquired in step S14 and stored in the RAM 92 by the first pressure sensor 78.

When the CPU 90 determines that the time T ₀ has elapsed (S36: YES), the CPU 90 sequentially outputs a close signal to the on-off valves 21, 79, and 80 to turn off (S37, S38, S39).
The CPU 90 sequentially outputs an open signal to the drain valves 84 and 85 and turns them on (S40, S41), and starts drainage processing.
PH gradually decreases as drainage proceeds. CPU90 determines whether PH acquired from the 1st pressure sensor 78 is larger than P0 (S42). When the CPU 90 determines that PH is greater than P0 (S42: YES), the above determination is repeated.
When the CPU 90 determines that PH is not greater than P0 (S42: NO), that is, when PH reaches the same pressure as P0, drainage is impossible, and drainage ends. This completes the second drainage process and returns to the main routine shown in FIG.
Here, although step S42 will be described in detail later, it may be determined whether or not the time of the j-th drainage process has elapsed.

After performing the second drainage process in step S5, the CPU 90 increments the drainage frequency j by “1” in step S6, and then returns the process to step S4.
When the CPU 90 determines in step S4 that the number of times j of drainage is not the set number n (S4: NO), the CPU 90 proceeds to step S5 again and performs the drainage processing in steps S31 to S42 as described above. When the CPU 90 determines in step S4 that the number of times j of drainage is the set number n (S4: YES), the CPU 90 sequentially outputs a close signal to the drain valves 85 and 84 to turn off (S7 and S8). The main routine of waste water treatment is finished. As described above, the CPU 90 repeatedly executes the drainage process of steps S31 to S42 until the drainage count j reaches the set count n.

Hereinafter, a method for calculating the set number n will be described.
FIG. 5 is a schematic cross-sectional view of the gas-liquid separator 83. A liquid level sensor 89 is provided at a predetermined position above the gas-liquid separator 83. The liquid level sensor 89 detects the water level in the gas-liquid separator 83. The liquid level sensor 89 is connected to the control unit 9 although not shown in detail.
As shown in FIG. 5A, the entire internal volume of the gas-liquid separator 83 is VD, the internal volume of the gas-liquid separator 83 from the top surface to the liquid level sensor 83 is VD1, and the gas / liquid from the liquid level sensor 89 to the bottom surface. Assume that the internal volume of the separator 83 is VD2 (that is, VD = VD1 + VD2), and the water level sensor 89 is filled with water.

Let VH be the internal volume of the hydrogen circulation path. The sum of the internal volume VH of the hydrogen circulation path and the internal volume VD1 in the gas-liquid separator 83 is the volume of gas, and the pressure of this gas is PH. If the volume increase due to the pressure change from PH to P0 (that is, the amount of wastewater from the first wastewater treatment) is VA,
From Boyle's law,
PH × (VH + VD1) = P0 × (VH + VD1 + VA)
When the above equation is modified, the first discharge amount VA is obtained by the following equation.
VA = {(PH−P0) / P0} × (VH + VD1)
Here, when P0 is 1 atm and PH is k atm, (PH−P0) / P0 = k−1, and by keeping (k−1) constant, the amount of drainage VAt per unit time is also constant. .
If VH + VD1 = v,
VA = v × (k−1)
It becomes.

Assuming that the time required for the first drainage is t ₁ , the increase in gas volume in the gas-liquid separator 83 after the first, second, third,. It becomes like 1.
That is, the increase in gas volume during the n-th wastewater treatment is expressed by the following formula (1).
v × (k−1) × k ⁿ⁻¹ (1)
The time required for the nth drainage treatment is represented by the following formula (2).
t _n = t ₁ × k ^n-1 (2)
In step S42 described above, when it is determined whether or not the j-th drainage treatment time has elapsed, the j-th drainage treatment time is obtained by the following equation (2) ′.
t _j = t ₁ × k ^j−1 (2) ′

The accumulated time of drainage from the first time to the nth time required to drain all the water in the gas-liquid separator 83 is expressed by the following formula (3).
t ₁ + t ₂ + t ₃ + ... + t _n
= T ₁ + (t ₁ × k) + (t ₁ × k ² ) + (t ₁ × k ³ ) +... + (T ₁ × k ⁿ⁻¹ )
= T ₁ (1 + k + k ² + k ³ + ... + kn ^-1 ) (3)
Since the volume of water in the gas-liquid separator 83 is VD2 = VD−VD1, the time T required to drain all of this is expressed by the following formula (4).
T = VD2 / VAt (4)
Therefore,
(T ₁ + t ₂ + t ₃ +... + T _n )> T (5)
When satisfy | filling, all the water in the gas-liquid separator 83 will be drained.
Here, when Expression (5) is expressed using Expression (3),
t ₁ (1 + k + k ² + k ³ +... + k ^n-1 )> T (6)
The minimum integer n satisfying the above equation (6) is set as the set number of times of wastewater treatment.
That is, the number of times of drainage n can be calculated using the time t ₁ required for the _first drainage.

With respect to the above formula (6), a calculation example using specific numerical values will be described below. Here, in order to simplify the description, the description will be made assuming that v = VD1. In addition, each numerical value in the following calculation examples is a numerical value appropriately used for explaining a calculation method of the set number n, and is not limited to this.
[Calculation Example 1]
Specifically, the set number n is obtained by substituting the following numerical values.
First drain time: t ₁ = 1
PH = k = 2
Total volume in the gas-liquid separator 83: VD = 11
Initial gas volume in the gas-liquid separator 83: VD1 = 1
Initial water volume in the gas-liquid separator 83: VD2 = 10
Drainage volume per unit time: VAt = 1

The time T required to discharge all the water in the gas-liquid separator 83 is 10/1 = 10 from the above equation (4).
Substituting the above numerical values, equation (6) becomes
(1 + 2 + 2 ² + ... + 2 ^n-1 > 10
Than this,
(1 + 2 + 2 ² +2 ³ ) = 15> 10
From the above, the minimum integer n satisfying the equation (6) is 4.
In this case, if the waste water treatment is performed four times, all the water in the gas-liquid separator 83 is discharged.

FIG. 6 is a schematic diagram for visualizing and explaining the waste water treatment of Calculation Example 1.
The leftmost diagram of FIG. 6 is a schematic diagram showing an initial state of the gas-liquid separator 83, and the gas volume VD1 from the upper surface of the gas-liquid separator 83 to the liquid level sensor 89 (not shown) is 1. The volume VD2 of water from the bottom surface of the gas-liquid separator 83 to the liquid level sensor 89 is 10.
In the first drainage treatment, the amount of discharged water is 1 × (2-1) = 1 from the above formula (1).
The drainage time is t ₁ = 1 as described above.
Similarly, when the amount of water discharged during the second to fourth drainage treatment and the drainage time are calculated, FIG. 6 is obtained. The ratio between the volume of gas after each drainage treatment and the volume of water is shown in the schematic diagram.
As shown in FIG. 6, when the remaining amount of water after the third drainage treatment was “3”, the drainage treatment was performed so that water was discharged for “8” at the fourth time. It can be seen that the water in 83 is completely discharged.

[Calculation Example 2]
Next, calculation example 2 when the value of k is changed will be described.
k = 1.5.
Total volume in gas-liquid separator: VD = 11
The initial gas volume VD1 = 1 in the gas-liquid separator is assumed to be the same as [Calculation Example 1].
However, the increase in gas volume after the first drainage and the drainage amount Vat per unit time change due to k = 1.5.
The amount of gas increase (= drainage amount) after the first drainage is 1 × (1.5−1) = 0.5 from the above formula (1).
The drainage amount VAt per unit time is VAt = 1 × 1.5 / 2 = 0.75 from the ratio of k.
Thus, the time t ₁ required for the first drainage is t ₁ = 0.5 / 0.75.

Therefore, equation (6) becomes
(0.5 / 0.75) × (1 + 1.5 + 1.5 ² +... +1.5 ^n-1 )> (10 / 0.75)
If this equation is transformed,
(1 + 1.5 + 1.5 ² + ... + 1.5 ^n-1 )> 20
(1 + 1.5 + 1.5 ² +1.5 ³ +1.5 ⁴ +1.5 ⁵ ) ≈20.8> 20
From the above, the minimum integer n that satisfies the equation (6) is 6.
In this case, if the waste water treatment is performed six times, all the water in the gas-liquid separator 83 is drained.

FIG. 7 is a schematic diagram for visualizing and explaining the waste water treatment of Calculation Example 2.
The leftmost diagram of FIG. 7 is a schematic diagram showing an initial state of the gas-liquid separator 83, and the gas volume VD1 from the upper surface of the gas-liquid separator 83 to the liquid level sensor 89 (not shown) is 1. The volume VD2 of water from the bottom surface of the gas-liquid separator 83 to the liquid level sensor 89 is 10.
In the first drainage treatment, the amount of discharged water is 0.5 as described above.
The drainage time t ₁ is 0.5 / 0.75 = 0.67 as described above.
Similarly, when the discharged water amount and drainage time during the second to sixth drainage treatments are calculated, the result is as shown in FIG. The ratio between the volume of gas after each drainage treatment and the volume of water is shown in the schematic diagram.
From FIG. 7, when the remaining amount of water after the fifth drainage treatment was “3.41”, the drainage treatment was performed so that the water was drained by “3.80” at the sixth time. It can be seen that the water in the liquid separator 83 is completely discharged.

As described above, in the present embodiment, the time t ₁ when the pressure of the gas in the hydrogen circulation path and the gas-liquid separator 83 changes from PH to P0 in the first drainage treatment is measured, and the gas-liquid is measured. Since the set number of times n is calculated based on the time T until the water in the separator 83 is completely discharged, the remaining water in the gas-liquid separator 83 is well suppressed and freezing can be prevented. .
Therefore, drainage can be performed satisfactorily at the next power generation, and the deterioration of the fuel cell function is prevented. And since drainage is performed with the on-off valve closed, even if the drainage valve breaks down, leakage of more than a specified amount of hydrogen can be prevented.

Hereinafter, modifications 1 and 2 of the fuel cell 300 will be described.
(Modification 1)
In the gas-liquid separator 83 of the fuel cell according to the modified example 1, the liquid level sensor 89 is not provided, and the volume of the gas in the gas-liquid separator 83 before performing the waste water treatment is defined as VD1, and the above formula (1) , (2), (4), and (6) are calculated. VD1 can be calculated by estimating the volume VD2 of water stored in the gas-liquid separator 83 based on, for example, the amount of supplied hydrogen or the amount of power generation.
In the first modification, the component cost can be reduced by omitting the liquid level sensor 89.

(Modification 2)
In the fuel cell of Modification 2, the set number of times n is calculated including the amount of water in the first drainage channel 74.
Assuming that the internal volume of the first drainage channel 74 is VC, the time T required to drain all of the water in the gas-liquid separator 83 and the water in the first drainage channel 74 is expressed by the following equation (4) ′. Is done.
T = (VD2 + VC) / VAt (4) ′
Using the T, the minimum integer n satisfying the equation (6) is set as the set number of times of wastewater treatment.
In the modified example 2, since the set number n is calculated including the internal volume of the drain pipe, it is possible to prevent water from remaining in the first drain path 74 and freezing.

  As described above, the fuel cell according to the present invention includes a power generation unit that generates electricity by reacting hydrogen and oxygen, a fuel unit that supplies hydrogen to the power generation unit, the on-off valve for supplying the hydrogen, A hydrogen circulation path that circulates the gas exhausted from the power generation section back to the power generation section, a gas-liquid separator that is provided in the hydrogen circulation path and separates water from the gas, and water from the gas-liquid separator A pressure detector for detecting a gas pressure in the hydrogen circulation path and the gas-liquid separator in a fuel cell comprising a drain valve for discharging, and a control unit for controlling the opening and closing valve and the opening and closing of the drain valve; A measuring unit that measures a time when the pressure acquired from the pressure detector changes by a predetermined amount, and the control unit is configured to control the on-off valve and the drain valve based on the time measured by the measuring unit. The wastewater treatment is performed by controlling the opening and closing.

In the present invention, from the state where the on-off valve is opened and the drain valve is closed, the increase in gas in the hydrogen circulation path based on the pressure difference when the on-off valve is closed and the drain valve is opened to open the hydrogen circulation path Therefore, when the water stored in the gas-liquid separator is pushed out and drained, the time when the pressure changes by a predetermined amount is estimated to estimate the next drainage time. It is possible to drain well so as to prevent water from remaining and prevent freezing.
Therefore, drainage can be performed satisfactorily at the next power generation, and the deterioration of the fuel cell function is prevented. And since drainage is performed with the on-off valve closed, even if the drainage valve breaks down, leakage of more than a specified amount of hydrogen can be prevented. In addition, the water level sensor becomes unnecessary, and the component cost can be reduced.

  In the fuel cell according to the present invention, in the fuel cell described above, the measurement unit measures a time until the first pressure detected by the pressure detector decreases to the second pressure in the first drainage treatment, The said control part calculates the frequency | count of performing wastewater treatment based on the said 1st pressure, the said 2nd pressure, and the said time.

  The time until the pressure in the hydrogen circulation path and the gas-liquid separator decreases from the first pressure to the second pressure is the drainage time of water in the gas-liquid separator. In the present invention, the time required for the first drainage is measured, and based on this drainage time, the number of times of drainage treatment for discharging all the water from the gas-liquid separator is calculated, and the wastewater treatment for that number of times is calculated. Therefore, it is possible to satisfactorily suppress water remaining in the gas-liquid separator.

  The fuel cell according to the present invention is the above-described fuel cell, wherein the control unit is configured to perform the first pressure, the second pressure, the time, the internal volume of the hydrogen circulation path, and the first drainage treatment. Based on the volume of the gas in the gas-liquid separator, the cumulative amount of drainage time when drainage treatment is performed from the first to the n-th time is calculated, and the cumulative amount> (water in the gas-liquid separator is N satisfying (volume) / (drainage amount per unit time) is calculated, and n is set to the number of times of wastewater treatment.

  In the present invention, the gas-liquid separator based on the pressure difference is based on the first pressure, the second pressure, the internal volume of the hydrogen circulation path, and the gas volume in the gas-liquid separator before the first drainage treatment. The increase in the volume of the gas inside is calculated, and the accumulated amount of drainage time when drainage treatment is performed from the first to the nth time is calculated based on the first drainage time. Then, n satisfying the cumulative amount> (volume of water in the gas-liquid separator) / (drainage amount per unit time) is calculated, and this is set as the number of times of wastewater treatment. Remaining can be suppressed more favorably.

  The fuel cell according to the present invention includes a drain pipe connecting the drain valve and the gas-liquid separator in the fuel cell described above, and the control unit includes the internal volume of the drain pipe and includes the drainage treatment. The number of times is calculated.

  In this invention, since the frequency | count of the said waste_water | drain process is calculated also including the internal volume of a drain pipe, it can prevent that water remains in a drain pipe and freezes.

  In the fuel cell control method according to the present invention, the on-off valve is opened to supply hydrogen from the fuel unit to the power generation unit, and the gas exhausted from the power generation unit is circulated back to the power generation unit through a hydrogen circulation path. In a control method of a fuel cell in which water is separated from the gas by a gas-liquid separator provided in a hydrogen circulation path and drainage treatment is performed by a drain valve, in the first drainage treatment, in the hydrogen circulation path and the gas-liquid The time until the first pressure of the gas in the separator is reduced to the second pressure is acquired, and the number of wastewater treatments is calculated based on the first pressure, the second pressure, and the time, and is calculated The waste water treatment is performed by controlling the opening and closing of the on-off valve and the drain valve for the number of times.

  In the present invention, the time required for the first drainage is measured, and based on this drainage time, the number of times for discharging all the water from the gas-liquid separator is calculated, and the wastewater treatment for that number of times is performed. The water remaining in the gas-liquid separator can be satisfactorily suppressed.

  A computer program according to the present invention is a computer that controls a fuel cell including a hydrogen circulation path that returns and circulates gas exhausted from a power generation unit, and a gas-liquid separator that separates and drains water from the gas. In the waste water treatment for the second time, the time until the first pressure of the gas in the hydrogen circulation path and the gas-liquid separator is reduced to the second pressure is acquired, and the first pressure, the second pressure, and the The number of times of waste water treatment is calculated based on the time, and processing for outputting an on / off signal for the on / off valve for supplying hydrogen and an on / off signal for the drain valve is executed according to the calculated number of times.

  In the present invention, the time required for the first drainage is measured, and based on this drainage time, the number of times for discharging all the water from the gas-liquid separator is calculated, and the wastewater treatment for that number of times is performed. The water remaining in the gas-liquid separator can be satisfactorily suppressed.

  The present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

For example, the water level sensor provided in the gas-liquid separator 83 is not limited to the liquid level sensor, and may be a float sensor or the like.
Further, when the external pressure P0 at the place where the fuel cell 300 is disposed may be 1 atm, the second pressure sensor 88 may not be provided.
And when P0 is not 1 atm, the above-mentioned formula VA = {(PH−P0) / P0} × (VH + VD1)
Substituting the numerical value of P0 into, obtain the set number of times n.

DESCRIPTION OF SYMBOLS 1 Stack 3 Air flow path 4 Stack cooling path 41 1st heat exchanger 42 2nd heat exchanger 5 Radiator flow path 6 Cylinder heating path 7 Hydrogen flow path 71 Hydrogen supply path 72 Hydrogen introduction path 73 Hydrogen circuit 74 1st Drainage path 75 First exhaust path 78 First pressure sensor 82 Hydrogen circulation pump 84, 85 Drain valve 86, 87 Exhaust valve 88 Second pressure sensor 89, 90 Liquid level sensor 9 Control unit 91 ROM
92 RAM
93 Timer 20 MH cylinder 30 Air pump 90 CPU
100 Battery Main Body 200 Hydrogen Supply Unit 300 Fuel Cell

Claims (6)

A power generation unit that generates electricity by reacting hydrogen and oxygen, a fuel unit that supplies hydrogen to the power generation unit, an on-off valve for supplying the hydrogen, and a gas exhausted from the power generation unit is returned to the power generation unit. A hydrogen circulation path for circulation, a gas-liquid separator provided in the hydrogen circulation path for separating water from the gas, a drain valve for discharging water from the gas-liquid separator, the on-off valve and the drain valve A fuel cell comprising a control unit for controlling the opening and closing of
A pressure detector for detecting the pressure of the gas in the hydrogen circulation path and the gas-liquid separator;
A measuring unit that measures the time when the pressure acquired from the pressure detector changes by a predetermined amount, and
The controller is
Based on the time measured by the measurement unit, the drainage treatment is performed by controlling the opening and closing of the on-off valve and the drain valve. The measuring unit is
In the first waste water treatment, the time until the first pressure detected by the pressure detector is reduced to the second pressure is measured,
The controller is
2. The fuel cell according to claim 1, wherein the number of times of wastewater treatment is calculated based on the first pressure, the second pressure, and the time. The control unit is based on the first pressure, the second pressure, the time, the internal volume of the hydrogen circulation path, and the volume of gas in the gas-liquid separator before the first drainage treatment, Calculate the cumulative amount of drainage time when drainage treatment is performed from the first to the nth,
N satisfying the cumulative amount> (volume of water in the gas-liquid separator) / (drainage amount per unit time) is calculated,
The fuel cell according to claim 2, wherein n is set to the number of times of waste water treatment. A drain pipe connecting the drain valve and the gas-liquid separator;
The controller is
4. The fuel cell according to claim 2, wherein the number of times of the wastewater treatment is calculated including the internal volume of the drainage pipe. A gas-liquid separator provided in the hydrogen circulation path by opening the on-off valve to supply hydrogen from the fuel section to the power generation section and circulating the gas exhausted from the power generation section back to the power generation section through the hydrogen circulation path In the control method of the fuel cell in which water is separated from the gas by the drainage treatment by the drainage valve,
In the first drainage treatment, the time until the first pressure of the gas in the hydrogen circulation path and the gas-liquid separator is reduced to the second pressure is obtained,
Based on the first pressure, the second pressure, and the time, calculate the number of wastewater treatment,
A control method for a fuel cell, wherein drainage treatment is performed by controlling opening and closing of the on-off valve and the drain valve for the calculated number of times. A computer that controls a fuel cell including a hydrogen circulation path that circulates the gas exhausted from the power generation unit, and a gas-liquid separator that separates and drains water from the gas.
In the first drainage treatment, the time until the first pressure of the gas in the hydrogen circulation path and the gas-liquid separator is reduced to the second pressure is obtained,
Based on the first pressure, the second pressure, and the time, calculate the number of wastewater treatment,
A computer program for executing a process of outputting an on / off signal for an on / off valve for supplying hydrogen and an on / off signal for a drain valve according to the calculated number of times.

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