JP7091708B2 - Fuel cell system - Google Patents

Description

The present invention relates to a fuel cell system.

Patent Document 1 discloses a fuel cell system that limits the take-out current of the fuel cell stack according to the cooling water temperature of the cooling water inlet of the fuel cell stack in order to suppress excessive heat generation of the fuel cell stack. ..

Japanese Unexamined Patent Publication No. 2005-0446229

However, when an abnormality occurs in the temperature sensor that measures the cooling water temperature at the cooling water inlet of the fuel cell stack, and the measured value of the temperature sensor and the actual cooling water temperature deviate from each other, the withdrawal current of the fuel cell stack May be over-restricted or under-restricted. As a result, there is a problem that the calorific value of the fuel cell stack exceeds a desired range. Further, the same problem occurs when the extraction current of the fuel cell stack is limited according to the cooling water temperature of the cooling water outlet of the fuel cell stack.

The present invention has been made to solve the above-mentioned problems, and can be realized as the following forms.
According to one embodiment of the present invention, a fuel cell system is provided. This fuel cell system includes a fuel cell, a cooling flow path in which a cooling medium for cooling the fuel cell circulates, a radiator provided in the cooling flow path, and a pump for pumping the cooling medium to the fuel cell. At the cooling medium inlet of the fuel cell to which the cooling medium is supplied from the cooling flow path, or at the cooling medium outlet of the fuel cell from which the cooling medium is discharged to the cooling flow path. The temperature sensor for measuring the temperature of the cooling medium, the heat dissipation equal value curve of the fuel cell obtained by using the outside temperature of the outside air and the upper limit temperature of the cooling medium when the temperature sensor is abnormal, and the said. The lower limit of the generated voltage of the fuel cell is calculated by using the current-voltage characteristic curve of the fuel cell according to the upper limit temperature, and the generated voltage of the fuel cell is controlled so as not to fall below the lower limit. It is equipped with a control unit. In the heat generation and heat dissipation equal value curve, the cooling system is driven by using the generated power of the fuel cell under the condition that the temperature of the outside air is the outside temperature and the temperature of the cooling medium is the upper limit temperature. The relationship between the generated current of the fuel cell and the generated voltage when the maximum amount of heat radiated from the fuel cell to the outside air via the radiator and the calorific value of the fuel cell become equal to each other is The current-voltage characteristic curve represents the relationship between the generated current of the fuel cell and the generated voltage when the temperature of the cooling medium is the upper limit temperature, and the control unit is used. , The generated voltage of the fuel cell at the intersection of the heat generation / heat dissipation equal value curve and the current-voltage characteristic curve is calculated as the lower limit value.
The present invention can also be realized in the following forms.

(1) According to one embodiment of the present invention, a fuel cell system is provided. In this fuel cell system, a fuel cell, a cooling flow path in which a cooling medium for cooling the fuel cell circulates, a cooling medium inlet of the fuel cell to which the cooling medium is supplied, or the cooling medium is discharged. The fuel cell obtained by using a temperature sensor for measuring the temperature of the cooling medium at the outlet of the cooling medium of the fuel battery and the outside temperature and the upper limit temperature of the cooling medium when the temperature sensor has an abnormality. The lower limit of the generated voltage of the fuel cell is calculated by using the heat generation and heat dissipation equal value curve of the above and the current-voltage characteristic curve of the fuel battery according to the upper limit temperature, and the lower limit value of the fuel cell is used. A control unit for controlling the generated voltage is provided.
According to this form of the fuel cell system, the control unit controls the generated voltage of the fuel cell by using the lower limit of the generated voltage, so that the calorific value of the fuel cell can be kept within a desired range, and the temperature sensor can be used. It is possible to prevent the calorific value of the fuel cell from exceeding a desired range due to the occurrence of an abnormality.

The present invention can also be realized in various forms other than the above. For example, it can be realized in the form of a fuel cell vehicle or the like.

The figure which shows typically the fuel cell system in 1st Embodiment. A flowchart illustrating the processing of voltage limitation or current limitation of a fuel cell. Explanatory drawing which exemplifies the heat generation heat dissipation equivalence curve and the current-voltage characteristic curve of a fuel cell. Explanatory drawing illustrating other heat generation and heat dissipation equivalence curves and current-voltage characteristic curves. Explanatory drawing which shows the current-voltage characteristic curve of another fuel cell. The flowchart illustrating the process of voltage limitation or current limitation of 2nd Embodiment. Explanatory drawing illustrating other heat generation and heat dissipation equivalence curves and current-voltage characteristic curves.

-First embodiment:
FIG. 1 is a diagram schematically showing a fuel cell system 10 according to the first embodiment. The fuel cell system 10 is mounted on a vehicle such as a bus as a power source, for example. The fuel cell system 10 includes a fuel cell 100, a power circuit 200, a cooling flow path 300, a control unit 700, an anode gas supply flow path (not shown), a cathode gas supply / discharge flow path, and the like.

The fuel cell 100 is configured by stacking a plurality of single cells (not shown). As the fuel cell 100, for example, a polymer electrolyte fuel cell can be adopted. The fuel cell 100 uses an anode gas and a cathode gas to generate electricity by an electrochemical reaction. As the anode gas, for example, hydrogen can be adopted, and as the cathode gas, for example, air can be adopted.

The electric power circuit 200 is a circuit that utilizes the electric power from the fuel cell 100. The power circuit 200 includes an FC boost converter 230, an inverter 240, a drive motor 250, a current sensor 260, and a voltage sensor 270. The power circuit 200 may include a storage battery, a battery converter, or the like.

The current sensor 260 detects the generated current of the fuel cell 100. The voltage sensor 270 detects the generated voltage of the fuel cell 100. The FC boost converter 230 is a DC / DC converter that adjusts the output voltage of the fuel cell 100. The FC boost converter 230 boosts the output voltage of the fuel cell 100 to a high voltage that can be used by the drive motor 250 in response to a control signal from the control unit 700. The inverter 240 converts the DC voltage boosted by the FC boost converter 230 into an AC voltage, adjusts the frequency and voltage of the AC voltage according to the control signal from the control unit 700, and supplies the AC voltage to the drive motor 250. , Controls the drive motor 250. The drive motor 250 can generate rotational power by electric power from the fuel cell 100 to drive the wheels of the vehicle.

The cooling flow path 300 is a flow path through which a cooling medium for cooling the fuel cell 100 circulates. As the cooling medium, for example, water, antifreeze water such as ethylene glycol, or the like can be adopted. The cooling flow path 300 has a supply flow path 310, a radiator 450, a discharge flow path 320, and a bypass flow path 330. One end of the supply flow path 310 is connected to the cooling medium inlet 110 to which the cooling medium of the fuel cell 100 is supplied, and the other end is connected to the radiator 450. The supply flow path 310 is provided with a cooling medium pump 340. The cooling medium pump 340 pumps and circulates the cooling medium. The radiator 450 releases the amount of heat of the cooling medium flowing through the radiator 450 to the outside by blowing air from the fan 440. One end of the discharge flow path 320 is connected to the radiator 450, and the other end is connected to the cooling medium outlet 120 from which the cooling medium of the fuel cell 100 is discharged. One end of the bypass flow path 330 is connected to the discharge flow path 320 via the three-way valve 350, and the other end is connected to the upstream side of the cooling medium pump 340 of the supply flow path 310. The three-way valve 350 divides the cooling medium in the discharge flow path 320 into the bypass flow path 330 and the radiator 450 in response to the control signal from the control unit 700. The cooling medium in the cooling flow path 300 is driven by the cooling medium pump 340, flows into the fuel cell 100 via the supply flow path 310, cools the fuel cell 100, and then flows into the discharge flow path 320. A part of the cooling medium in the discharge flow path 320 flows through the radiator 450 through the three-way valve 350, is cooled, and returns to the supply flow path 310 again. The other part of the cooling medium in the discharge flow path 320 flows through the bypass flow path 330 through the three-way valve 350 and returns to the supply flow path 310 again.

In the discharge flow path 320, the first temperature sensor 370 is installed in the vicinity of the cooling medium outlet 120 of the fuel cell 100. The first temperature sensor 370 measures the temperature of the cooling medium at the cooling medium outlet 120. The measured value of the first temperature sensor 370 is substantially the same as the temperature value of the fuel cell 100. Instead of installing the first temperature sensor 370, a temperature sensor for measuring the temperature of the cooling medium at the cooling medium inlet 110 may be installed near the cooling medium inlet 110 of the fuel cell 100 of the supply flow path 310. .. In the supply flow path 310, a second temperature sensor 380 is installed in the vicinity of the radiator outlet 420 of the radiator 450. The second temperature sensor 380 measures the temperature of the cooling medium at the radiator outlet 420. The fuel cell system 10 is equipped with an outside temperature sensor 20 that measures the temperature of the environment in which the fuel cell system 10 is placed.

The control unit 700 is composed of a microcomputer including a central processing unit and a main storage device, and is specifically an ECU (Electronic Control Unit). The control unit 700 controls the operation of each unit in the fuel cell system 10 according to the user's request, the measured value of each sensor in the fuel cell system 10, and the like. The control unit 700 controls the power generation current of the fuel cell 100 by using the measured value of the first temperature sensor 370 in order to suppress the excessive heat generation of the fuel cell 100. On the other hand, when the control unit 700 has an abnormality in the first temperature sensor 370, that is, the temperature difference between the measured value of the first temperature sensor 370 and the actual temperature of the cooling medium at the cooling medium outlet 120 is predetermined. When the range is equal to or greater than the error range of the first temperature sensor 370, the generated voltage of the fuel cell 100 is controlled by using the lower limit of the generated voltage of the fuel cell 100 (described later).

FIG. 2 is a flowchart illustrating the details of the process in which the control unit 700 (FIG. 1) executes the voltage limitation or the current limitation with respect to the fuel cell 100 (FIG. 1). The process shown in FIG. 2 is repeatedly executed during the operation of the fuel cell system 10 (FIG. 1). In step S110, the control unit 700 acquires the measured temperature of the cooling medium at the cooling medium outlet 120 of the fuel cell 100 (hereinafter referred to as “outlet cooling medium measured temperature”) from the first temperature sensor 370. In step S120, the control unit 700 calculates the estimated temperature of the cooling medium at the cooling medium outlet 120 (hereinafter referred to as “outlet cooling medium estimated temperature”). The calculated outlet cooling medium estimated temperature is considered to be the actual temperature of the cooling medium at the cooling medium outlet 120. The outlet cooling medium estimated temperature is, for example, the estimated temperature of the cooling medium at the cooling medium inlet 110 of the fuel cell 100 (hereinafter referred to as “inlet cooling medium estimated temperature”), the calorific value of the fuel cell 100, and the cooling medium pump 340. It can be calculated using the flow rate of the cooling medium in. The estimated inlet cooling medium temperature can be calculated, for example, by using the measured temperature of the cooling medium at the radiator outlet 420 acquired from the second temperature sensor 380 and the diversion ratio of the three-way valve 350. The calorific value of the fuel cell 100 can be calculated by using, for example, the power generation current of the fuel cell 100.

In step S130, the control unit 700 determines whether or not there is an abnormality in the first temperature sensor 370 by comparing the outlet cooling medium measurement temperature obtained by steps S110 and S120 with the outlet cooling medium estimated temperature. .. When the temperature difference between the outlet cooling medium measurement temperature and the outlet cooling medium estimated temperature is equal to or greater than the above-mentioned allowable range, the control unit 700 determines that the first temperature sensor 370 has an abnormality (step S130, Yes). The process proceeds to step S140. In step S140, the control unit 700 calculates the lower limit of the generated voltage of the fuel cell 100 by using the heat generation and heat dissipation equality curve of the fuel cell 100 and the current-voltage characteristic curve. Here, a method of calculating the lower limit value of the power generation voltage of the fuel cell 100 will be described with reference to FIGS. 3 and 4.

FIG. 3 is an explanatory diagram illustrating the heat generation and heat dissipation equivalence curve Q1 and the current-voltage characteristic curve G3 of the fuel cell 100. FIG. 4 is an explanatory diagram illustrating the heat generation and heat dissipation equivalence curve Q2 and the current-voltage characteristic curve G3 of the fuel cell 100. The heat generation and heat dissipation equivalence curves Q1 and Q2 are virtual current-voltage characteristic curves plotting the operating points of the fuel cell 100 when the calorific value of the fuel cell 100 and the maximum heat radiation amount from the fuel cell 100 to the outside air become equal. .. In the example of FIG. 3, the region R1 on the left side of the heat generation / heat dissipation equality curve Q1 is a region where the heat generation amount of the fuel cell 100 is smaller than the maximum heat dissipation amount, and the region R2 on the right side of the heat generation / heat dissipation equality curve Q1 is the fuel. This is a region where the heat generation amount of the battery 100 is larger than the maximum heat dissipation amount. The "maximum heat radiation amount" is an amount that can release heat from the fuel cell 100 to the outside air when the temperature of the cooling medium at the cooling medium outlet 120 reaches the upper limit temperature. The "upper limit temperature" is the maximum temperature at which the cooling medium is allowed depending on the configuration of the fuel cell system 10. The heat generation and heat dissipation equivalence curves Q1 and Q2 are obtained by using the outside air temperature and the upper limit temperature of the cooling medium. As the outside air temperature, the assumed maximum outside air temperature may be used, or the measured value of the outside air temperature acquired from the outside air temperature sensor 20 may be used. As the assumed maximum outside air temperature, for example, 30 ° C to 40 ° C can be adopted. In the example of FIG. 3, the heat generation and heat dissipation equivalence curve Q1 is a curve obtained by using the assumed maximum outside air temperature. In the example of FIG. 4, the heat generation and heat dissipation equivalence curve Q2 is a curve obtained by using the measured value of the outside air temperature lower than the assumed maximum outside air temperature. The current-voltage characteristic curve G3 of the fuel cell 100 is a predetermined current-voltage characteristic curve corresponding to the upper limit temperature of the cooling medium.

In the example of FIG. 3, the control unit 700 calculates the lower limit value of the power generation voltage of the fuel cell 100 by using the heat generation and heat dissipation equal value curve Q1 and the current-voltage characteristic curve G3. Specifically, the control unit 700 sets the voltage Vmin1 corresponding to the intersection P1 between the heat generation and heat dissipation equality curve Q1 and the current-voltage characteristic curve G3 as the lower limit of the generated voltage of the fuel cell 100. The intersection P1 is an operating point that can actually be taken by the fuel cell 100 when the calorific value of the fuel cell 100 becomes equal to the maximum heat dissipation amount. If the power generation voltage of the fuel cell 100 is limited to the lower limit value Vmin1 or more, the operating point of the fuel cell 100 can be limited to the region R1 in which the heat generation amount does not exceed the maximum heat dissipation amount, so that excessive heat generation of the fuel cell 100 can be suppressed. ..

Similarly, in the example of FIG. 4, the control unit 700 calculates the lower limit value of the power generation voltage of the fuel cell 100 by using the heat generation and heat dissipation equality curve Q2 and the current-voltage characteristic curve G3. Specifically, the control unit 700 sets the voltage Vmin2 corresponding to the intersection P2 between the heat generation and heat dissipation equality curve Q2 and the current-voltage characteristic curve G3 as the lower limit of the generated voltage of the fuel cell 100. Since the heat generation and heat dissipation equivalence curve Q2 in FIG. 4 is obtained by using the measured value of the outside temperature lower than the assumed maximum outside temperature used to obtain the heat generation and heat dissipation equivalence curve Q1 in FIG. 3, the heat generation of the fuel cell 100 is generated. The region R3 in which the amount is smaller than the maximum heat dissipation amount is larger than the corresponding region R1 in FIG. 3, and the region R4 in which the heat generation amount of the fuel cell 100 is larger than the maximum heat dissipation amount is smaller than the corresponding region R2 in FIG. That is, the maximum heat dissipation amount of the fuel cell 100 in the case of FIG. 4 is larger than the maximum heat dissipation amount of the fuel cell 100 in the case of FIG. Therefore, the lower limit value Vmin2 of the generated voltage of the fuel cell 100 in FIG. 4 is smaller than the lower limit value Vmin1 of the generated voltage of the fuel cell 100 in FIG. 3, and the range of operating points that the fuel cell 100 in FIG. 4 can take is shown in FIG. It is larger than the range of operating points that the fuel cell 100 in 3 can take.

Returning to FIG. 2, in step S160, the control unit 700 controls the power generation voltage of the fuel cell 100 using the lower limit value of the power generation voltage of the fuel cell 100. Specifically, the control unit 700 limits the power generation voltage of the fuel cell 100 so that the power generation voltage of the fuel cell 100 is equal to or higher than the lower limit value Vmin1 (Vmin2). The control unit 700 ends the process after executing step S160.

Returning to step S130, the control unit 700 determines that there is no abnormality in the first temperature sensor 370 when the temperature difference between the outlet cooling medium measurement temperature and the outlet cooling medium estimated temperature is smaller than the above-mentioned allowable range. Step S130, No), the process proceeds to step S150. In step S150, the control unit 700 controls the power generation current of the fuel cell 100 by using the outlet cooling medium measurement temperature acquired from the first temperature sensor 370. Here, a method of limiting the generated current of the fuel cell 100 will be described with reference to FIG.

FIG. 5 is an explanatory diagram showing current-voltage characteristic curves G1, G2, and G3 of the fuel cell 100. The current-voltage characteristic curves G1, G2, and G3 are predetermined current-voltages corresponding to the first temperature T1, the second temperature T2, and the third temperature (upper limit temperature) T3 of the cooling medium at the cooling medium outlet 120. It is a characteristic curve. The current-voltage characteristic curve G3 is the same as the current-voltage characteristic curve G3 shown in FIGS. 3 and 4. The temperatures T1 to T3 satisfy the first temperature T1 <second temperature T2 <third temperature T3. In the example of FIG. 5, when the outlet cooling medium measurement temperature is the first temperature T1 or more, the control unit 700 limits the generated current of the fuel cell 100 to the current I1 or less, so that the operating point of the fuel cell 100 Is limited to the operating point on the current-voltage characteristic curve G1 on the left side of the point N1. When the outlet cooling medium measurement temperature is the second temperature T2 or higher, the control unit 700 limits the generated current of the fuel cell 100 to the current I2 or less so that the operating point of the fuel cell 100 is on the left side of the point N2. It is limited to the operating point on the current-voltage characteristic curve G2. When the outlet cooling medium measurement temperature is the third temperature T3 or higher, the control unit 700 limits the generated current of the fuel cell 100 to the current I3 or less, so that the operating point of the fuel cell 100 is set to the left side of the point N3. It is limited to the operating point on the current-voltage characteristic curve G3. The control unit 700 ends the process after executing step S150.

As described above, in the first embodiment, the control unit 700 uses the heat generation and heat dissipation equality curve Q1 (Q2) and the current-voltage characteristic curve G3 according to the upper limit temperature of the cooling medium at the cooling medium outlet 120. The lower limit value Vmin1 (Vmin2) of the power generation voltage of the fuel cell 100 is calculated, and the power generation voltage of the fuel cell 100 is controlled by using the lower limit value Vmin1 (Vmin2) of the power generation voltage. By doing so, the calorific value of the fuel cell 100 can be kept within a desired range without using the temperature measured by the outlet cooling medium by the first temperature sensor 370. Therefore, the fuel cell due to an abnormality in the first temperature sensor 370. It is possible to prevent the calorific value of 100 from exceeding a desired range.

-Second embodiment:
FIG. 6 is a flowchart illustrating the details of the process in which the control unit 700 (FIG. 1) in the second embodiment executes the voltage limitation or the current limitation with respect to the fuel cell 100 (FIG. 1). In FIG. 6, the difference from the first embodiment shown in FIG. 2 is that it is determined whether or not the first temperature sensor 370 has an abnormality.

In FIG. 6, in step S210, the control unit 700 calculates the lower limit value of the generated voltage of the fuel cell 100 by using the heat generation and heat dissipation equal value curve of the fuel cell 100 and the current-voltage characteristic curve. Step S210 is the same as step S140 shown in FIG. In step S220, the control unit 700 calculates the estimated current range. The “estimated current range” is a current range including the current value at the operating point corresponding to the lower limit value of the generated voltage on the current-voltage characteristic curve corresponding to the measured temperature of the outlet cooling medium of the fuel cell 100. The estimated current range is calculated in consideration of the error of the voltage sensor 270 and the current sensor 260. Here, the steps after step S220 will be described with reference to FIG. 7.

FIG. 7 is a diagram corresponding to FIG. 3 of the first embodiment, and is a diagram in which a current-voltage characteristic curve G1 corresponding to the first temperature T1 shown in FIG. 5 is added. In FIG. 7, the outlet cooling medium measurement temperature is assumed to be the third temperature T3 (upper limit temperature), and the outlet cooling medium estimated temperature (the actual temperature of the cooling medium at the cooling medium outlet 120) is assumed to be the first temperature T1. That is, in the example of FIG. 7, the current-voltage characteristic curve according to the outlet cooling medium measurement temperature is the current-voltage characteristic curve G3, but the current-voltage characteristic curve of the actual fuel cell 100 is the current-voltage characteristic curve G1. Is. Further, in FIG. 7, the temperature difference between the first temperature T1 and the third temperature T3 is equal to or greater than the above-mentioned allowable range. That is, in the example of FIG. 7, there is an abnormality in the first temperature sensor 370. The estimated current range Yes is a current range on the current-voltage characteristic curve G3 including the current value Imax1 at the operating point P1 corresponding to the lower limit value Vmin1 of the generated voltage of the fuel cell 100 calculated in step S210. Here, when there is an abnormality in the first temperature sensor 370, when the measured value of the voltage sensor 270 becomes the lower limit value Vmin1 of the generated voltage, the measured value of the current sensor 260 becomes the current value Ims, which deviates from the estimated current range Yes. It becomes the value to be. Therefore, the control unit 700 can determine whether or not there is an abnormality in the first temperature sensor 370 by using the estimated current range and the measured values of the voltage sensor 270 and the current sensor 260.

In step S230, the control unit 700 determines whether or not the generated voltage of the fuel cell 100 acquired from the voltage sensor 270 is equal to or less than the lower limit of the generated voltage calculated in step S210. When the power generation voltage of the fuel cell 100 is equal to or less than the lower limit of the power generation voltage (step S230, Yes), the control unit 700 proceeds to step S240. In step S240, whether the generated current of the fuel cell 100 acquired from the current sensor 260 deviates from the estimated current range when the measured value of the voltage sensor 270 becomes the lower limit of the generated voltage calculated in step S210. Judge whether or not. When the generated current of the fuel cell 100 deviates from the estimated current range (step S240, Yes), the control unit 700 proceeds to step S250 and determines that the first temperature sensor 370 has an abnormality. In step S260, the control unit 700 controls the power generation voltage of the fuel cell 100 by using the lower limit value of the power generation voltage of the fuel cell 100. Step S260 is the same as step S160 shown in FIG. The control unit 700 ends the process after executing step S160.

Returning to step S230, the control unit 700 proceeds to step S270 when the generated voltage of the fuel cell 100 is larger than the lower limit of the generated voltage (steps S230, No). In this case, since the calorific value of the fuel cell 100 is smaller than the maximum heat dissipation amount, it is not necessary to limit the power generation voltage of the fuel cell 100 by using the lower limit of the power generation voltage. In step S270, the control unit 700 controls the power generation current of the fuel cell 100 by using the outlet cooling medium measurement temperature acquired from the first temperature sensor 370. Step S270 is the same as step S150 shown in FIG.

Returning to step S240, the control unit 700 determines that there is no abnormality in the first temperature sensor 370 when the generated current of the fuel cell 100 does not deviate from the estimated current range (step S240, No), and steps S270. Move to. The control unit 700 ends the process after executing step S270.

In FIG. 7, the current-voltage characteristic curve of the fuel cell 100 may change from the current-voltage characteristic curve G1 to the current-voltage characteristic curve G3 due to the lack of cathode gas in the fuel cell 100. In this case, the control unit 700 may increase the amount of cathode gas supplied to the fuel cell 100 before executing step S240. In this way, the control unit 700 can suppress the change in the current-voltage characteristic curve due to the lack of cathode gas, and can reliably determine whether or not there is an abnormality in the first temperature sensor 370.

Also in the second embodiment, the control unit 700 uses the heat generation and heat dissipation equality curve Q1 and the current-voltage characteristic curve G3 corresponding to the upper limit temperature of the cooling medium at the cooling medium outlet 120 to lower the lower limit of the generated voltage of the fuel cell 100. The value Vmin1 is calculated, and the power generation voltage of the fuel cell 100 is controlled by using the lower limit value Vmin1 of the power generation voltage. By doing so, the calorific value of the fuel cell 100 can be kept within a desired range without using the temperature measured by the outlet cooling medium by the first temperature sensor 370. Therefore, the fuel cell due to an abnormality in the first temperature sensor 370. It is possible to prevent the calorific value of 100 from exceeding a desired range.

The present invention is not limited to the above-described embodiment, and can be realized with various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each embodiment described in the column of the outline of the invention are for solving a part or all of the above-mentioned problems, or one of the above-mentioned effects. It is possible to replace or combine as appropriate to achieve the part or all. Further, if the technical feature is not described as essential in the present specification, it can be appropriately deleted.

10 ... Fuel cell system 20 ... Outside temperature sensor 100 ... Fuel cell 110 ... Cooling medium inlet 120 ... Cooling medium outlet 200 ... Power circuit 230 ... FC boost converter 240 ... Inverter 250 ... Drive motor 260 ... Current sensor 270 ... Voltage sensor 300 ... Cooling flow path 310 ... Supply flow path 320 ... Discharge flow path 330 ... Bypass flow path 340 ... Cooling medium pump 350 ... Three-way valve 370 ... First temperature sensor 380 ... Second temperature sensor 420 ... Radiator outlet 440 ... Fan 450 ... Radiator 700 … Control unit

Claims (1)

It ’s a fuel cell system.
With a fuel cell
A cooling system having a cooling flow path in which a cooling medium for cooling the fuel cell circulates, a radiator provided in the cooling flow path, and a pump for pumping the cooling medium to the fuel cell.
The temperature of the cooling medium at the cooling medium inlet of the fuel cell to which the cooling medium is supplied from the cooling flow path or the cooling medium outlet of the fuel cell from which the cooling medium is discharged to the cooling flow path is measured. With the temperature sensor
When there is an abnormality in the temperature sensor, the heat generation and heat dissipation equivalence curve of the fuel cell obtained by using the outside temperature of the outside air and the upper limit temperature of the cooling medium, and the current-voltage of the fuel cell according to the upper limit temperature. A control unit that calculates the lower limit of the generated voltage of the fuel cell using the characteristic curve and controls the generated voltage of the fuel cell so as not to fall below the lower limit.
Equipped with
In the heat generation and heat dissipation equal value curve, the cooling system is driven by using the generated power of the fuel cell under the condition that the temperature of the outside air is the outside temperature and the temperature of the cooling medium is the upper limit temperature. The relationship between the generated current of the fuel cell and the generated voltage when the maximum amount of heat radiated from the fuel cell to the outside air via the radiator and the calorific value of the fuel cell become equal to each other is Represented and
The current-voltage characteristic curve shows the relationship between the generated current of the fuel cell and the generated voltage when the temperature of the cooling medium is the upper limit temperature.
The control unit calculates the generated voltage of the fuel cell at the intersection of the heat generation and heat dissipation equality curve and the current-voltage characteristic curve as the lower limit value.
Fuel cell system.

Images