WO2009054428A1

WO2009054428A1 - Fuel cell system

Info

Publication number: WO2009054428A1
Application number: PCT/JP2008/069176
Authority: WO
Inventors: Naoki Kanie; Masahiro Okuyoshi
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2007-10-25
Filing date: 2008-10-16
Publication date: 2009-04-30

Abstract

A fuel cell system comprises a fuel cell, a containing device for containing water discharged from the fuel cell, and a state estimation section for estimating the state of the containing device based on the state of the fuel cell.

Description

Specification

Fuel cell system

Technical field

The present invention relates to a fuel cell system including a fuel cell.

Background art

As a fuel cell system including a storage device that stores water discharged from the fuel cell, a fuel cell system including a temperature sensor in the storage device is known in order to determine the state of the storage device.

On the other hand, it is desired to reduce the size and weight of the fuel cell system in order to be mounted on a vehicle or the like. In the fuel cell system as described above, the state of the storage device can be changed without using a temperature sensor. The technology to judge was desired. Disclosure of the invention

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the size or weight of a fuel cell system including a storage device.

The present invention has been made to solve at least a part of the problems described above, and the first aspect provides a fuel cell system. A fuel cell system according to a first aspect includes a fuel cell, a storage device that stores water discharged from the fuel cell, and a state in which the state of the storage device is estimated based on the state of the fuel cell An estimation unit;

According to the fuel cell system configured as described above, since the state of the storage device can be estimated without providing a temperature sensor or the like in the storage device, the fuel cell system can be reduced in size or weight.

In the fuel cell system according to the first aspect, the state estimation unit may estimate whether or not the water is stored in the storage device based on an internal resistance value of the fuel cell. In this way, the storage state of the water in the storage device is changed to the storage device. The estimation can be performed without providing a temperature sensor or the like.

In the fuel cell system according to the first aspect, the state estimation unit determines whether or not the water is stored in the storage device, in the fuel cell, the internal resistance value at the end of the previous power generation. In this way, the storage state of the water in the storage device can be estimated based on the internal resistance value at the end of the previous power generation of the fuel cell without providing a temperature sensor or the like in the storage device. Can be estimated.

The fuel cell system according to the first aspect further includes a refrigerant flow path for flowing a refrigerant for cooling the fuel cell,

In the case where the water is stored in the storage device, the state estimation unit may estimate the state of the water based on the refrigerant temperature of the refrigerant flow path. In this way, the state of water in the storage device can be estimated without providing a temperature sensor or the like in the storage device.

In the fuel cell system according to the first aspect, at least a part of the refrigerant flow path has a height difference in the vertical direction, and the storage device includes a high-order part and a low-order part of the refrigerant flow path. The state estimation unit is in a state in which the refrigerant in the refrigerant flow path is stopped before the fuel cell power generation is started, and is disposed in contact with the fuel cell. When the refrigerant temperature in the lower portion of the flow path is higher than the first threshold, the water state may be estimated as a liquid that is not in the supercooled state. In this way, the state of water in the storage device can be estimated without providing a temperature sensor or the like in the storage device.

In the fuel cell system according to the first aspect, at least a part of the refrigerant flow path has a height difference in the vertical direction, and the storage device includes a high-order part and a low-order part of the refrigerant flow path. The state estimation unit is in a state in which the refrigerant in the refrigerant flow path is stopped before the fuel cell power generation is started, and is disposed in contact with the fuel cell. The refrigerant temperature in the lower part of the flow path is equal to or lower than a second threshold value, and the refrigerant temperature in the higher part of the refrigerant flow path is smaller than the second threshold value. If it is greater than the third threshold, the water state may be estimated as a supercooled state. In this way, the state of water in the storage device can be estimated without providing a temperature sensor or the like in the storage device.

A fuel cell system according to a first aspect, comprising: a discharge valve for discharging the water from the storage device; and a valve control unit that controls opening and closing of the discharge valve, wherein the valve control unit includes the state When the estimation unit estimates the water state as a supercooled state, the discharge valve may be opened until a predetermined condition is satisfied. In this way, when the supercooled water in the storage device reaches the discharge valve, it can be prevented from freezing and the discharge valve becoming uncontrollable.

In the fuel cell system according to the first aspect, at least a part of the refrigerant flow path has a height difference in the vertical direction, and the storage device includes a high-order part and a low-order part of the refrigerant flow path. The state estimation unit is in a state in which the refrigerant in the refrigerant flow path is stopped before the fuel cell power generation is started, and is disposed in contact with the fuel cell. When the temperature of the refrigerant in the lower portion of the flow path is equal to or lower than a fourth threshold value, and the temperature of the refrigerant in the higher portion of the refrigerant flow path is equal to or lower than a fifth threshold value that is smaller than the fourth threshold value. The water state may be estimated as a frozen state. In this way, the state of the water in the storage device can be estimated without providing a temperature sensor or the like in the storage device.

In the fuel cell system according to the first aspect, the storage device includes a discharge valve for discharging the water, and the fuel cell system includes a refrigerant flow path for flowing a cooling medium for cooling the fuel cell, and A valve temperature estimation unit that estimates the discharge valve temperature; and a valve temperature storage unit that stores the discharge valve temperature estimated by the valve temperature estimation unit, wherein the valve temperature estimation unit generates power from the fuel cell. At the start, the refrigerant temperature is detected, and the detected temperature of the refrigerant and the discharge valve temperature stored in the valve temperature storage unit at the end of the previous power generation, the lower temperature is started The exhaust valve temperature at the time may be estimated. In this way, for example, the fuel cell finishes generating electricity, When the power generation of the fuel cell is immediately started and the refrigerant temperature is higher than the predetermined value and the actual drain valve temperature is lower than the predetermined value, the drain valve temperature at the end of the previous fuel cell power generation is Since it is estimated as the valve temperature, it is possible to suppress misjudgment that the drain valve temperature is equal to or higher than the predetermined value, and accordingly, misjudgment that the drain valve may be frozen is suppressed. can do. As a result, it is possible to prevent the drain valve from becoming uncontrollable.

In the fuel cell system according to the first aspect, the valve temperature estimation unit detects the refrigerant temperature when newly estimating the exhaust valve temperature during power generation of the fuel cell, and detects the detected refrigerant temperature. You may estimate based on refrigerant | coolant temperature and the said discharge valve temperature estimated last time. In this way, it is possible to accurately estimate the discharge valve temperature.

In the fuel cell system according to the first aspect, the valve temperature estimation unit may determine whether or not the discharge valve is likely to freeze based on the estimated discharge valve temperature. In this way, it is possible to accurately determine whether or not the discharge valve may freeze.

The fuel cell system according to the first aspect, further comprising: a discharge valve freezing information storage unit, wherein if the valve temperature estimation unit determines that the discharge valve may be frozen, the discharge valve freezing information storage unit The unit may store freezing possibility information indicating that the discharge valve may be frozen. In this way, it is possible to quickly determine whether or not the discharge valve can be controlled to open.

The fuel cell system according to the first aspect, further comprising: a discharge valve freezing information storage unit, wherein the valve temperature estimation unit determines that the discharge valve is not likely to freeze, The portion may store freezing possibility release information indicating that the discharge valve has almost no possibility of freezing. In this way, it is possible to quickly determine whether or not the discharge valve can be controlled to open.

In the fuel cell system according to the first aspect, the refrigerant flow path includes the fuel cell. Five

It may be formed inside or in the vicinity of the fuel cell. In this way, the temperature distribution of the refrigerant in the refrigerant flow path quickly corresponds to the temperature distribution of the fuel cell, so that the state of the water in the reservoir can be accurately estimated based on the refrigerant temperature. .

In addition to the fuel cell system described above, the present invention can be realized in the form of a control circuit of the fuel cell system, or an apparatus invention of a vehicle or the like equipped with the fuel cell system. Further, the present invention is not limited to the device invention, and can be realized as a method invention such as a control method for a fuel cell system. Furthermore, an aspect as a computer program for constructing these methods and apparatuses, an aspect as a recording medium recording such a computer program, and a data signal embodied in a carrier wave including the above computer program It can also be realized in various ways.

Further, when the present invention is configured as a computer program or a recording medium that records the program, it may be configured as an entire program for controlling the operation of the apparatus, or only a part that performs the function of the present invention. What constitutes

Brief Description of Drawings

FIG. 1 is a block diagram showing a schematic configuration of a fuel cell system according to a first embodiment of the present invention.

FIG. 2 is a front view of an end plate disposed at one end of the fuel cell. FIG. 3 is a flowchart showing a processing routine of the water state estimation processing executed by the fuel cell system of the first embodiment.

FIG. 4 is a block diagram showing a schematic configuration of the fuel cell system according to the second embodiment of the present invention.

FIG. 5 is a flowchart showing the process of the exhaust drainage valve temperature estimation process executed by the fuel cell system of the second embodiment. FIG. 6 is an explanatory diagram showing an example of a timing chart in the exhaust drainage valve temperature estimation process. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described based on several embodiments with reference to the drawings.

A. First Example:

A 1. Configuration of fuel cell system 1 000:

FIG. 1 is a block diagram showing a schematic configuration of a fuel cell system 1000 according to the first embodiment of the present invention. In Figure 1, the X direction is defined as the direction indicated by the arrow in the figure. The fuel cell system 1 000 of the present embodiment mainly includes a fuel cell 100, a hydrogen tank 200, a compressor 230, a control circuit 400, a refrigerant circulation pump 500, and a temperature sensor 5 2 0, 5 30. , A radiator 5 5 0, a gas-liquid separator 6 00, an exhaust / drain valve 6 1 0, a hydrogen circulation pump 2 5 0, a hydrogen shut-off valve 2 1 0, and a resistance measuring device 900. .

The fuel cell 100 is a polymer electrolyte fuel cell that is relatively small and excellent in power generation efficiency. The fuel cell 100 includes a fuel cell 20, end plates 300 A and 300 B, a tension plate 3 10, insulators 3 30 A and 3 30 B, and terminals 34 OA and 34 OB. Yes. Specifically, the fuel cell 100 is laminated in the order of an end plate 300A, an insulator 330A, a terminator 340A, a plurality of fuel cells 20, a terminal 340B, an insulator 33OB, and an end plate 300B. The tension plates 3 10 are coupled to the end plates 300 by bolts 3 20, whereby each fuel cell 20 is fastened with a predetermined force in the stacking direction.

The fuel battery cell 20 includes a membrane electrode assembly (not shown), an anode side separator (not shown), and a force sword side separator (not shown). Membrane electrode contact The coalescence includes an electrolyte membrane (not shown), a force sword (not shown) and an anode (not shown) as electrodes, and a gas diffusion layer (not shown). It consists of an electrolyte membrane on the surface of which a positive electrode is sandwiched between gas diffusion layers. The fuel cell 20 is configured by further sandwiching this membrane electrode assembly with an anode side separator and a cathode side separator.

The hydrogen tank 200 is a storage device for storing high-pressure hydrogen gas, and is connected to a fuel cell 100 (a fuel gas supply manifold described later) via a fuel gas supply channel 20 4. Yes. On the fuel gas supply channel 20 4, a hydrogen shut-off valve 2 10 and a pressure regulating valve (not shown) are provided in order from the hydrogen tank 2 0 0. By opening the hydrogen shut-off valve 2 1 0, hydrogen gas is supplied to the fuel cell 1 0 0 as fuel gas. Instead of the hydrogen tank 200, hydrogen may be generated by a reforming reaction using alcohol, hydrocarbon, aldehyde, or the like as a raw material, and supplied to the anode side.

The compressor 2 3 0 is connected to the fuel cell 1 0 0 (oxidizing gas supply manifold described later) via the oxidizing gas supply flow path 2 3 4, and compresses air and supplies it to the power sword as oxidizing gas To do. In addition, the fuel cell 100 (the oxidizing gas discharge manifold described later) is connected to the oxidizing gas discharge flow path 2 36 and the oxidizing gas after being subjected to the electrochemical reaction with the power sword is the oxidizing gas. It is discharged to the outside of the fuel cell system 1 0 0 0 through the discharge flow path 2 3 6.

FIG. 2 is a front view of the end plate 300 B arranged at one end of the fuel cell 100. Specifically, FIG. 2 corresponds to a view of the end plate 300 B of FIG. 1 viewed from the X direction. Furthermore, in FIG. 2, the downward direction is the vertical downward direction, and the upward direction is the vertical upward direction. Hereinafter, the fuel cell system 100 will be described with reference to FIG. 1 and FIG.

Inside the fuel cell 100, there are a fuel gas supply MH I (see Fig. 2), a fuel gas discharge MH OH (see Fig. 2), and an oxidant gas supply mulch (see Fig. 2). 8

(Not shown), an oxidizing gas discharge manifold (not shown), and a refrigerant discharge manifold M L O (see FIG. 2). Fuel gas supply manifold MH I supplies fuel gas to each fuel cell 20, and fuel gas discharge manifold MH O discharges fuel gas from each fuel cell 20 to the outside of the fuel cell 10 0 0 The oxidizing gas supply manifold supplies the oxidizing gas to each fuel cell 20, and the oxidizing gas discharge manifold discharges the oxidizing gas from each fuel cell 20 to the outside of the fuel cell 100. The refrigerant supply manifold MLI supplies refrigerant between the fuel cells 20. The external connection port of the refrigerant supply manifold MLI (hereinafter also referred to as the refrigerant supply port) is located vertically below the fuel cell 100 and the external connection port of the refrigerant discharge manifold (hereinafter referred to as (Also referred to as a refrigerant outlet) is arranged on the upper side in the vertical direction of the fuel cell 100. As the refrigerant, water or a mixed liquid of water and ethylene glycol (antifreeze) can be used.

The refrigerant supply manifold M L I (refrigerant supply port) and the refrigerant discharge manifold M L O (refrigerant discharge port) of the fuel cell 100 are respectively connected to the refrigerant circulation flow path 5 10. The flow path formed by the refrigerant supply manifold M L I, the refrigerant discharge manifold M L O, and the refrigerant circulation flow path 51 is also referred to as a refrigerant circulation system flow path.

A refrigerant circulation pump 500 and a radiator 55 are provided on the refrigerant circulation channel 51. The radiator 55 50 cools the refrigerant warmed by the fuel cell 100, and the refrigerant circulation pump 50 00 supplies the refrigerant cooled by the radiator 55 50 to the fuel cell 100. As a result, the fuel cell 100 can be continuously cooled by the refrigerant.

In the refrigerant circulation system flow path, a temperature sensor 5 20 is disposed at the refrigerant supply port, and a temperature sensor 5 30 is disposed at the refrigerant discharge port. That is, the temperature sensor 5 20 is a sensor for detecting the refrigerant temperature [° C] (hereinafter also referred to as the low refrigerant temperature T 1) in the lower part of the refrigerant circulation system flow path. 5 3 0 is the refrigerant temperature [° C] (higher refrigerant temperature T 2 at the higher position in the refrigerant circulation system flow path. It is also a sensor for detecting.

As shown in FIG. 2, the gas-liquid separator 600 is connected to the fuel gas discharge manifold MH O of the fuel cell 100 via the fuel gas discharge flow path 206. The gas-liquid separator 60 is composed of a condensing unit 60 A that condenses water vapor contained in the fuel gas discharged from the fuel cell 100, a condensed water condensed by the condensing unit 60 OA, and a fuel cell. The storage unit 6 0 0 B stores water discharged as liquid water from 1 0 0. Hereinafter, the water stored in the storage unit 6 10 B is referred to as stored water. Further, as shown in FIG. 2, the gas-liquid separator 600 is vertically disposed between the refrigerant supply port (refrigerant discharge manifold MLO) and the refrigerant discharge port (refrigerant supply manifold MLI). And the side surface of the fuel cell 10 0 0 0 is arranged in contact with the end plate 3 0 0 B of the fuel cell 1. Further, the gas / liquid separator 60 is provided with an exhaust drain valve 6 10. The exhaust / drain valve 6 1 0 is connected to the exhaust / drain passage 6 2 0. During operation of the fuel cell system 1 0 0 0, by periodically opening the exhaust drain valve 6 1 0, the concentration of impurities (for example, nitrogen) after being subjected to an electrochemical reaction at the anode increases. The fuel gas in the reservoir 6 0 0 B is periodically stored in the fuel gas discharge channel 2 0 6, gas-liquid separator 6 0 0, exhaust drain valve 6 1 0, and exhaust drain The fuel cell system 10 0 0 is discharged to the outside through the flow path 6 2 0.

Further, the gas-liquid separator 60 0 0 is connected to the fuel gas supply flow path 20 4 via the gas circulation flow path 2 07 as shown in FIGS. A hydrogen circulation pump 25 50 is provided on the gas circulation flow path 20 7. The fuel gas discharged from the fuel cell 10 0 (fuel gas discharge mold MH O) to the gas-liquid separator 6 0 0 is passed through the gas circulation flow path 2 0 7 by the hydrogen circulation pump 2 5 0. Then, it is introduced into the fuel gas supply flow path 204. In this way, the hydrogen gas contained in the fuel gas circulates and is used as a fuel gas for power generation. It should be noted that an ion exchange device for removing ions in the liquid water that can be discharged from the fuel cell 100 is provided at the connection between the gas-liquid separator 600 and the fuel gas discharge flow path 206. Good. The resistance measuring device 900 is connected to the terminals 340A and 340B of the fuel cell 100 via the wiring 9 1 0, and measures the internal resistance value of the fuel cell 100 (hereinafter referred to as the FC resistance value). To do. Specifically, the resistance measuring apparatus 900 applies an alternating current of a predetermined frequency between the terminator 34 OA and 34 OB and detects the voltage between the terminator 340A and 340B. The resistance measuring device 900 measures the FC resistance value based on the phase difference between the AC component of the applied current and the AC component of the detected voltage, and the frequency of the AC component of the current and voltage.

By the way, the electrolyte membrane in each fuel cell 20 of the fuel cell 100 has a property that the membrane resistance is low in the wet state and the membrane resistance is high in the dry state. Therefore, in the fuel cell 100, if a large amount of water stays inside the FC resistance value, the FC resistance value becomes low, and if there is little water staying inside, the FC resistance value becomes high. That is, the FC resistance value can be considered as an index of the water retention state inside the fuel cell 100.

In addition, when the fuel cell 100 is not generating power and the refrigerant circulation pump 500 is not driven, the higher refrigerant temperature T 2 is reduced to the lower refrigerant temperature T by the refrigerant convection in the refrigerant circulation passage. A temperature distribution occurs in which the temperature is higher than 1. In this case, the refrigerant supply manifold ML I in the fuel cell 1001 has a higher heat capacity than the other members in the refrigerant discharge manifold MLO. Temperature distribution occurs to correspond to the temperature distribution of the Mull Hold ML I and the refrigerant discharge manifold MLO. Here, as described above, the gas-liquid separator 600 is disposed between the refrigerant supply port from which the lower refrigerant temperature T1 is detected and the refrigerant outlet from which the higher refrigerant temperature T2 is detected. Since the side surface of the fuel cell 100 is in contact with the end plate 300 B of the fuel cell 100, the temperature of the stored water in the gas-liquid separator 600 is equal to the high refrigerant temperature T 2 and the low refrigerant temperature T 1. It can be estimated that the temperature is between.

The control circuit 400 is configured as a logic circuit centered on a microcomputer. It is. Specifically, a CPU (not shown) that executes predetermined calculations according to a preset control program, and control programs and control data necessary for executing various calculation processes by the CPU are stored in advance. ROM (not shown), RAM 4 2 0 for reading and writing various data necessary to perform various arithmetic operations on the CPU, and input / output ports for inputting / outputting various signals (not shown) ) Etc. The control circuit 40 0 is connected to an input / output port through a control signal line (not shown), a hydrogen shutoff valve 2 1 0, a compressor 2 3 0, a hydrogen circulation pump 2 5 0, and a refrigerant circulation pump 5 0. 0, exhaust drain valve 6 1 0, resistance measuring device 9 0 °, etc. are controlled, that is, the entire fuel cell system 1 0 0 0 is controlled. The control circuit 400 also receives detection signals from various sensors including a temperature sensor via a detection signal line (not shown).

The control circuit 40 0 also functions as a state estimation unit 4 10, and executes water state estimation processing described later. In addition, the control circuit 400, at the end of power generation of the fuel cell 10 0, causes the resistance measuring device 90 0 to connect to the FC resistance value of the fuel cell 1 0 0 (hereinafter referred to as the same resistance value 1 1). Is detected and stored in RAM 4 2 0. A 2. Water condition estimation process:

FIG. 3 is a flowchart showing a processing routine of water state estimation processing executed by the fuel cell system 100 according to this embodiment. This water state estimation process is executed before the power generation of the fuel cell 100 is started. That is, it is executed before the refrigerant circulation pump 5 0 0, the compressor 2 3 0, and the hydrogen circulation pump 2 5 0 are driven, and the hydrogen cutoff valve 2 1 0 and the exhaust drain valve 6 1 0 are closed Executed in state. The water state estimation process is a process for estimating the state in the gas-liquid separator 600 before the start of power generation of the fuel cell 100. That is, whether or not the stored water exists in the gas-liquid separator 600, and if the stored water exists, the stored water is liquid water that is not supercooled water, supercooled water, and a frozen state. It is the process which estimates which state is.

In the water state estimation process, the state estimation unit 4 1 0 first sets the resistance value 1 1 to 18 Read from M420 (step S 1 0). Next, the state estimation unit 4 10 estimates whether or not the FC resistance value R i is equal to or less than the threshold value R th (step S 20).

When the FC resistance value R i is larger than the threshold value R th (step S 20: No), the state estimation unit 4 1 0 is in the fuel cell 1 00 when the previous power generation of the fuel cell 1 0 0 ends. Therefore, it is estimated that there is no stored water (or almost no stored water) in the gas-liquid separator 600 (step S 30). Thereafter, the state estimation unit 4 10 ends this process.

When the FC resistance value R i is equal to or less than the threshold value R th (step S20: Y es), the state estimation unit 4 10 0 causes water to enter the fuel cell 100 when the previous power generation of the fuel cell 100 ends. It is presumed that there was a large amount of stagnation, and it is presumed that there is retained water in the gas-liquid separator 600 (step S 35).

Next, the state estimation unit 4 10 detects the lower refrigerant temperature T 1 from the temperature sensor 5 20 (step S 40).

The state estimation unit 4 10 estimates whether or not the lower refrigerant temperature T 1 is equal to or lower than the threshold value T th h 1 (step S 50). This threshold value T t h 1 is appropriately determined based on the specific design of the fuel cell system 1 000 and the like, and can be set to “0” indicating the melting point of water, for example.

When the lower refrigerant temperature T 1 is higher than the threshold T th 1 (step S 50: No), the state estimation unit 4 10 0 determines that the temperature of the stored water in the gas-liquid separator 600 is the threshold T th 1 Therefore, it is estimated that the stored water in the gas-liquid separator 600 is not a supercooled liquid (step S60). Thereafter, the state estimation unit 4 10 ends this process.

If the lower refrigerant temperature T 1 is equal to or lower than the threshold T th 1 (step S 50: Y es), the state estimating unit 4 10 subsequently detects the higher refrigerant temperature T 2 from the temperature sensor 53. (Step S70).

The state estimation unit 4 1 0 estimates whether or not the higher refrigerant temperature T 2 is equal to or lower than a threshold T th 2 (Step S 80). This threshold value T th 2 is smaller than the threshold value T th 1. The threshold value T th 2 is appropriately determined based on the specific design of the fuel cell system 100 °. For example, the threshold value T th 2 can be changed from the supercooled state to the frozen state when the supercooled water is stable. The temperature may be between “1 2 0” to “1 4 0”.

When the higher refrigerant temperature T 2 is higher than the threshold T th 2 (step S 80: No), the state estimating unit 4 1 0 determines that the temperature of the stored water in the gas-liquid separator 60 0 is the threshold T th. It is estimated that the stored water in the gas-liquid separator 60 0 is in a supercooled state because it is considered to be higher than 2 and within the range of the threshold value T th 1 (step S 90). Thereafter, the state estimation unit 4 10 ends this process.

When the higher refrigerant temperature T 2 is equal to or lower than the threshold value T th 2 (step S 80: Y es), the state estimation unit 4 10 0 determines that the temperature of the stored water in the gas-liquid separator 60 0 is the threshold value. Since it is considered that T th is 2 or less, it is estimated that the water stored in the gas-liquid separator 60 0 is in a frozen state (step S 1 0 0). Thereafter, the state estimation unit 4 10 ends this process.

After the water state estimation process, the control circuit 40 0 drives the refrigerant circulation pump 5 0 0, the compressor 2 3 0, the hydrogen circulation pump 2 5 0, etc., and opens the hydrogen shut-off valve 2 1 0, and the fuel cell 1 0 0 power generation starts. In the above water state estimation process, the control circuit 40 0 estimates that there is no stored water (Fig. 3: Step S 3 0), or if the stored water is estimated as liquid water that is not supercooled ( Fig. 3: Step S 60 0) or when the stored water is estimated to be frozen (Fig. 3: Step S 1 0 0), open / close control of the exhaust drain valve 6 1 0 periodically without restriction Then, the fuel gas with a high impurity concentration and the stored water in the storage unit 600 B are discharged to the outside of the fuel cell system 100 0 0.

On the other hand, in the water state estimation process, the control circuit 400, when the state estimation unit 4 10 has estimated that the stored water is in a supercooled state (FIG. 3: step S90), the fuel After the start of power generation of the battery 100, the exhaust drain valve 61 0 is not controlled until the stored water escapes from the supercooled state. The control circuit 4 0 0 is, for example, a fuel cell 1 0 0 When a predetermined time has elapsed from the start of power generation, heat transferred from the fuel cell 100 to the gas-liquid separator 60, condensation heat when water vapor in the fuel gas condenses, or fuel cell 100 It is estimated that the stored water has escaped from the supercooled state due to the heat of the liquid water discharged from the tank, and the open / close control of the exhaust drain valve 6 10 is released.

As described above, in the fuel cell system 100 according to the present embodiment, the state of the gas-liquid separator 6 0 0 is changed to the FC resistance of the fuel cell without providing a temperature sensor in the gas-liquid separator 6 0 0. It is estimated based on the value R i, or the lower refrigerant temperature T l, or the higher refrigerant temperature Τ2. In this way, it is possible to realize a small size or a light weight of the fuel cell system 100.

Further, in the fuel cell system 100 according to the present embodiment, the control circuit 4 0 0 determines that the state estimation unit 4 1 0 estimates that the stored water is in a supercooled state (FIG. 3: step S 9 On the other hand, after the start of power generation of the fuel cell 10 0, valve opening control of the exhaust / drain valve 6 10 is not performed until the stored water escapes from the supercooled state. In this way, it is possible to prevent the control of opening / closing of the exhaust drain valve 6 1 0 from being caused by freezing of the overcooled stored water flowing through the exhaust drain valve 6 10. be able to.

The gas-liquid separator 6 0 0 and the exhaust drain valve 6 1 0 correspond to the storage device in the claims, and the exhaust drain valve 6 1 0 corresponds to the discharge valve in the claims, and the state estimation unit 4 1 0 Corresponds to the state estimation unit in the claims, and the refrigerant discharge manifold ML ○, the refrigerant supply manifold MLI, the refrigerant circulation channel 5 10, or the refrigerant circulation system channel is the refrigerant in the claims The threshold value T th 1 corresponds to one of the first threshold value, the second threshold value, and the fourth threshold value in the claim range, and the threshold value T th 2 corresponds to the third threshold value in the claim range or Corresponding to the fifth threshold value, the control circuit 400 corresponds to the valve control unit in the claims. B. Second embodiment:

B 1. Fuel cell system 1 0 0 0 A configuration: 15

FIG. 4 is a block diagram showing a schematic configuration of the fuel cell system 100 O A according to the second embodiment of the present invention. The fuel cell system 100 A OA of the present embodiment has basically the same configuration as the fuel cell system 100 00 of the first embodiment, but the control circuit 40 0 0 has a valve temperature estimation unit 4 30 is different, and is different in that RAM 4 2 0 is provided with a reference value table KB, a flag table FB, and test data KD. The other configuration of the fuel cell system 10 0 O A is the same as that of the fuel cell system 100 0 0. In addition, the fuel cell system 100 0 A performs water state estimation processing in the same manner as the fuel cell system 1 0 0 0 of the first embodiment, and further, exhaust drainage provided in the gas-liquid separator 6 0 0 Estimate the temperature of the valve 6 10, and based on that temperature, the exhaust drain valve freezing flag that indicates whether or not the exhaust drain valve 6 1 0 is likely to freeze. An estimation process is also performed.

The valve temperature estimator 4 30 performs exhaust drainage valve temperature estimation processing. Reference value table ■ KB stores the exhaust drain valve temperature Tb estimated in the exhaust drain valve temperature estimation process. The exhaust drainage valve temperature stored in this reference value table KB then becomes the reference value for estimating the repeat exhaust drainage valve temperature Tb, and is also referred to below as the previous estimated temperature KK. The flag table FB stores the exhaust drain valve freezing possibility flag FG. The test formula data KD is data representing a test formula obtained experimentally in advance, and details will be described later. The exhaust drain valve temperature estimation process will be described below. FIG. 5 is a flowchart showing a processing routine of exhaust drainage valve temperature estimation processing executed by the fuel cell system 100 A of this embodiment. FIG. 6 is an explanatory diagram showing an example of a timing chart in the exhaust drain valve temperature estimation process. In Fig. 6, the horizontal axis represents time t. The exhaust drain valve temperature estimation process is performed from immediately before power generation of the fuel cell 100 0 in the fuel cell system 100 OA until after the end of power generation. At the start of the exhaust drain valve temperature estimation process, power generation of the fuel cell 100 is not performed. In other words, the refrigerant circulation pump 5 0 0, the compressor 2 3 0, and the hydrogen circulation pump 2 5 0 are not driven, and the hydrogen cutoff valve 2 1 0 and the exhaust drain valve 6 1 0 The valve is closed. The power generation of the fuel cell 100 is started after the process of step S 1 00 described later.

First, the valve temperature estimating unit 4 30 detects the lower refrigerant temperature T 1 from the temperature sensor 520 (step S 100). After this processing, power generation of the fuel cell 100 is started, that is, the refrigerant circulation pump 500, the compressor 230, and the hydrogen circulation pump 250 are driven, and the hydrogen shut-off valve 2 10 is opened. (See Figure 6: tl, t 3).

Subsequently, the valve temperature estimation unit 430 reads the previous estimated temperature KK from the reference value table KB (step S 1 1 0). The valve temperature estimation unit 430 compares the lower refrigerant temperature T 1 detected in the process of step S 100 with the read previous estimated temperature KK (step S 120).

When the lower refrigerant temperature T 1 is equal to or lower than the previous estimated temperature KK (step S 120: Y es), the valve temperature estimation unit 43 0 sets the lower refrigerant temperature T 1 as the previous estimated temperature KK in the reference value table KB. Remember (Step S 1 3◦). When the lower refrigerant temperature T 1 is higher than the previous estimated temperature KK (step S 120: No), the valve temperature estimation unit 430 proceeds to the process of step S 140.

Next, the valve temperature estimating unit 430 redetects the lower refrigerant temperature T 1 (step S 140). The valve temperature estimation unit 4 3 0 reads the verification formula data KD, and substitutes the lower refrigerant temperature T l and the previous estimated temperature KK into the verification formula indicated by the verification formula data KD, so that the exhaust drain valve temperature at that time T b is estimated (step S 150). Here, the test formula indicated by the test formula data KD will be described. In the fuel cell system 1 000 A, due to the positional relationship, the lower refrigerant temperature T 1 is easily affected by the fuel cell 100, and the exhaust drain valve temperature Tb is more responsive than the lower refrigerant temperature T 1. Is bad. Therefore, when the temperature of the fuel cell 100 rises, the lower refrigerant temperature T 1 rises quickly, and the exhaust drain valve temperature T b rises slightly later than the lower refrigerant temperature T 1. The test formula takes into account such a response delay in temperature, and uses the previously estimated temperature KK as a reference value. This is an equation for estimating the exhaust drainage valve temperature Tb from the value of the lower refrigerant temperature T1.

The valve temperature estimation unit 430 performs the process of step S 150 at the beginning of power generation of the fuel cell 100 (for example, FIG. 6: at time t 3), that is, the fuel cell 100 0 When the exhaust drainage valve temperature Tb is estimated for the first time at the start of power generation, the previous estimated temperature KK stored in the reference value table KB is estimated as the exhaust drainage valve temperature Tb. “At the start of power generation” is a concept including from immediately before the start of power generation to immediately after the start of power generation. In this case, the previous estimated temperature KK is the lower one of the lower refrigerant temperature T 1 detected in step S 100 and the exhaust drain valve temperature Tb at the end of power generation of the previous fuel cell 100. It is. In other words, during the predetermined power generation period, the lower temperature of the exhaust drain valve temperature Tb at the end of power generation of the previous fuel cell 100 or the lower refrigerant temperature T1 detected at the start of power generation. However, this is the initial temperature of the exhaust drain valve 6 10. For example, in FIG. 6, the power generation of the fuel cell 100 starts at t3, but the lower refrigerant temperature T1 at that time is larger than the threshold Tth1, and the exhaust drain valve temperature Tb at the time t2 (previous Since the estimated temperature KK) is less than the threshold value T thi, the exhaust drainage valve temperature T b (previously estimated temperature KK) at t 2, that is, at the end of power generation of the previous fuel cell, is Estimated as valve temperature T b.

Subsequently, the valve temperature estimation unit 4 30 stores the estimated exhaust drain valve temperature Tb in the reference value table KB as the previous estimated temperature KK (step S 1 60).

The valve temperature estimation unit 430 determines whether or not the exhaust / drain valve temperature T b is equal to or lower than a threshold value T th 1 (see the first embodiment) (step S 1 70). When the exhaust drain valve temperature T b is equal to or lower than the threshold T th 1 (step S 1 70: Y es), the valve temperature estimation unit 4 30 indicates that the exhaust drain valve 6 10 may be frozen. The exhaust drain valve freezing possibility flag FG stored in the flag table FB is turned ON (step S 1 80). For example, in FIG. 6, at t1, which is the start of power generation, the exhaust drain valve temperature T b is less than the threshold T th 1, so the exhaust drain valve freezing possibility flag FG is turned ON. The

On the other hand, when the exhaust drain valve temperature T b is larger than the threshold value T th 1 (step S 1 70: No), the valve temperature estimation unit 43 0 determines that the exhaust drain valve 6 10 may be frozen. If not, the exhaust drainage valve freezing possibility flag FG stored in the flag table FB is set to OF (step S 1 90). For example, in FIG. 6, when the exhaust drain valve temperature Tb slightly exceeds the threshold value T t h 1 (at t4), the exhaust drain valve freezing flag FG is set to OFF.

Subsequently, the valve temperature estimation unit 430 determines whether or not the power generation of the fuel cell 100 is finished (step S 200). When the power generation of the fuel cell 100 does not end (step S 200: No), the valve temperature estimation unit 430 returns to the process of step S 140, and performs the process of steps S 140 to S 180 Or, the processing from step S 1 4◦ to step S 1 90 is repeated. On the other hand, when the power generation of the fuel cell 100 ends (step S200: Y e s), the valve temperature estimation unit 430 ends the exhaust drain valve temperature estimation process.

When the exhaust drainage valve freezing possibility flag FG stored in the flag table FB is ON, the control circuit 400 controls to open the exhaust drainage valve 6 1 0 as necessary. When the valve freezing possibility flag FG is OF F, the exhaust drain valve 6 10 is not controlled to open.

By the way, for example, the lower refrigerant temperature T 1 is equal to or higher than the threshold T th 1 due to power generation of the fuel cell 100, but the temperature of the exhaust drain valve 6 10 is less than the threshold T th 1 and the fuel cell 100 When power generation is completed (for example, Fig. 6: t2) and power generation of the fuel cell 100 is started immediately (for example, Fig. 6: t3), the lower refrigerant temperature T1 at that time is exhausted and drained. Considering the temperature of the valve 6 10, the lower refrigerant temperature T 1 may be equal to or higher than the threshold value T thi. That is, the actual temperature of the exhaust drain valve 6 10 is less than the threshold T th 1 but is erroneously determined to be equal to or higher than the threshold T th 1 and the exhaust drain valve freezing possibility flag FG becomes OF F. There was a risk of it. In this situation, T 脑 08/069176

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There was a possibility that the water stored in the liquid separator 600 and the water present in the exhaust drain valve 61 were supercooled water. Then, based on this misjudgment, the exhaust drain valve 6 1 0 is opened, and the super exhaust water is frozen while the exhaust drain valve 6 1 0 is open, and the exhaust drain valve 6 1 0 is controlled. There was a risk of becoming impossible.

On the other hand, in the exhaust drain valve temperature estimation process performed by the fuel cell system 100 A of this embodiment, when the exhaust drain valve temperature T b is estimated for the first time at the start of power generation of the fuel cell 100, it is detected at that time. The lower one of the lower refrigerant temperature T 1 and the exhaust drain valve temperature T b at the end of power generation of the previous fuel cell 10 0 is estimated as the exhaust drain valve temperature τ b . In this way, for example, when the power generation of the fuel cell 10 0 ends and the power generation of the fuel cell 100 immediately starts, the temperature of the lower refrigerant temperature T 1 is equal to or higher than the threshold T th 1 and actually If the exhaust drain valve temperature Tb is less than the threshold T th 1, the exhaust drain valve temperature T b at the end of power generation of the previous fuel cell 100 is estimated as the current exhaust drain valve temperature T b It is possible to prevent the exhaust drain valve freezing flag FG from being turned OFF by erroneously determining that the exhaust drain valve temperature τ b is equal to or higher than the threshold value T th 1. As a result, the exhaust drain valve 6 10 can be prevented from becoming uncontrollable.

In the exhaust drain valve temperature estimation process performed by the fuel cell system 1 0 0 0 A of this embodiment, the initial value of the exhaust drain valve temperature T b is estimated, and then the previous estimated temperature KK is used as a reference value, and the exhaust drain valve temperature T b Is estimated. In this way, the exhaust drain valve temperature T b can be accurately estimated.

In addition, in the fuel cell system of the present embodiment, the exhaust drain valve temperature estimation process performed by the OA determines whether the exhaust drain valve 6 10 may freeze based on the exhaust drain valve temperature Tb. Is determined. In this way, it is possible to accurately determine whether or not the exhaust / drain valve 6 10 may freeze.

In this embodiment, the exhaust drain valve 6 10 corresponds to the discharge valve in the claims, the refrigerant circulation channel 5 10 corresponds to the refrigerant channel in the claims, and the valve temperature estimation unit 4 3 0 008/069176

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Corresponds to the valve temperature estimator in the claim, and the state that the exhaust drainage valve freezing possibility flag FG is ON corresponds to the freezing possibility information in the claim, and the exhaust drainage valve freezing flag FG is OFF Corresponds to the freezing possibility release information in the claims, and the flag table FB corresponds to the discharge valve freezing information storage unit in the claims.

C. Variations:

It should be noted that elements other than those claimed in the independent claims among the constituent elements in each of the above embodiments are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C 1. Modification 1:

In the fuel cell system 100 of the above embodiment, in the water state estimation process (FIG. 3), the control circuit 400 detects whether or not there is stored water in the gas-liquid separator 60 The fuel cell 1 0 0 was based on the FC resistance value R i at the end of the previous power generation, but the present invention is not limited to this. For example, the control circuit 400 causes the resistance measurement device 900 to detect the FC resistance value of the fuel cell 100 before executing the water state estimation process or during the previous power generation of the fuel cell 100. Based on the FC resistance value, it may be estimated whether or not there is stored water in the gas-liquid separator 60. Even if it does in this way, there can exist an effect similar to the said Example.

Further, the control circuit 400 detects the fuel cell temperature of the fuel cell 10 0 during the previous power generation of the fuel cell 100 0 or at the end of the power generation, and the gas-liquid is detected based on the fuel cell temperature. It may be possible to estimate whether or not there is stored water in the separator 600. In this case, the control circuit 400 detects, for example, the higher refrigerant temperature T2, which is the refrigerant outlet temperature, as the fuel cell temperature. In this way, the presence / absence of the stored water in the gas-liquid separator 600 can be estimated without providing the resistance measuring device 900. 08 069176

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As a result, the fuel cell system 100 can be reduced in size or weight.

Further, the control circuit 40 0 detects the output current value of the fuel cell 10 0 during the previous power generation of the fuel cell 100 0 or at the end of the power generation, and based on the output current value, the gas-liquid separator It may be estimated whether or not there is stored water in 600. In this way, it is possible to estimate the presence / absence of the stored water in the gas-liquid separator 600 without providing the resistance measuring device 900, so the fuel cell system 100 can be downsized. Or, weight reduction can be realized.

C 2. Modification 2:

The fuel cell system 100 of the above embodiment can be mounted on, for example, a vehicle such as an automobile, a ship, an airplane, or a linear motor force. In this way, it is possible to reduce the size or weight of such a mounting device.

C 3. Modification 3:

In the fuel cell system 100 OA of the above embodiment, in the exhaust drain valve temperature estimation process, the lower refrigerant temperature T 1 is used as the refrigerant temperature, but the present invention is not limited to this, The higher refrigerant temperature T 2 may be used. Even in this case, the same effects as in the above embodiment can be obtained.

C 4. Modification 4:

In the fuel cell system 1 00 OA of the above embodiment, in the exhaust drain valve temperature estimation process, the low refrigerant temperature T 1 and the previous estimated temperature KK are calculated in the process from step S 1 0 0 to step S 1 3 0. In comparison, the smaller temperature is stored in the reference value table KB as a new previous estimated temperature KK, but the present invention is not limited to this. For example, the higher refrigerant temperature T 2 is detected, the lower refrigerant temperature T 1, the higher refrigerant temperature Τ 2 and the previous estimated temperature Κ 比較 are compared, and the lowest temperature is set as the new previous estimated temperature Κ It may be stored in the value table KB. in this way The effect of the Example can be exhibited.

Claims

The scope of the claims

1. a fuel cell system,

A fuel cell;

A storage device for storing water discharged from the fuel cell;

A fuel cell system comprising: a state estimating unit that estimates the state of the storage device based on the state of the fuel cell.

2. In the fuel cell system according to claim 1,

The fuel cell system, wherein the state estimation unit estimates whether or not the water is stored in the storage device based on an internal resistance value of the fuel cell.

3. In the fuel cell system according to claim 2,

The fuel cell system, wherein the state estimating unit estimates whether or not the water is stored in the storage device based on the internal resistance value at the end of the previous power generation in the fuel cell.

4. The fuel cell system according to any one of claims 1 and 3 further includes a refrigerant flow path for flowing a refrigerant for cooling the fuel cell,

The said state estimation part estimates the state of the said water based on the refrigerant | coolant temperature of the said refrigerant | coolant flow path, when the said water is stored in the said storage apparatus.

5. In the fuel cell system according to claim 4,

At least a part of the refrigerant flow path has a vertical difference in the vertical direction, and the storage device is between a high-order part and a low-order part of the refrigerant flow path, and Placed in contact with the fuel cell,

The state estimating unit is in a state where the refrigerant temperature in the lower portion of the refrigerant flow path is larger than a first threshold value in a state in which the refrigerant in the refrigerant flow path is stopped before the start of power generation of the fuel cell. A fuel cell system that estimates the water state as a liquid that is not in a supercooled state.

6. In the fuel cell system according to claim 4,

At least a part of the refrigerant flow path has a height difference in the vertical direction, and the storage device is between a high-order part and a low-order part of the refrigerant flow path, and is connected to the fuel cell. Arranged in contact,

The state estimation unit is in a state where the refrigerant in the refrigerant flow path is stopped before the start of power generation of the fuel cell and the refrigerant temperature in the lower part of the refrigerant flow path is equal to or lower than a second threshold value. The fuel cell system estimates the water state as a supercooled state when the refrigerant temperature in the higher portion of the refrigerant flow path is larger than a third threshold value that is smaller than the second threshold value.

7. In the fuel cell system according to claim 5,

The state estimating unit is in a state where the refrigerant in the refrigerant flow path is stopped before the start of power generation of the fuel cell and the refrigerant temperature in the lower part of the refrigerant flow path is equal to or lower than a second threshold value. The fuel cell system estimates the water state as a supercooled state when the refrigerant temperature in the higher portion of the refrigerant flow path is larger than a third threshold value that is smaller than the second threshold value.

8. In the fuel cell system according to claim 6 or 7,

The storage device includes a discharge valve for discharging the water,

The fuel cell system includes a valve control unit that controls opening and closing of the discharge valve, 5. The fuel cell system according to claim 4, wherein the valve control unit does not open the discharge valve until a predetermined condition is satisfied when the state estimation unit estimates the water state as a supercooled state. In the fuel cell system described in

At least a part of the refrigerant flow path has a height difference in the vertical direction, and the storage device is between a high-order part and a low-order part of the refrigerant flow path, and is in contact with the fuel cell. Arranged,

The state estimating unit is in a state where the refrigerant in the refrigerant flow path is stopped before the fuel cell starts generating power, and the temperature of the refrigerant in the lower portion of the refrigerant flow path is equal to or lower than a fourth threshold value. The fuel cell system estimates the water state as a frozen state when the refrigerant temperature in the higher portion of the refrigerant flow path is equal to or lower than a fifth threshold value that is smaller than the fourth threshold value.

10. The fuel cell system according to any one of claims 5 to 8, wherein the state estimation unit is in a state in which the refrigerant in the refrigerant flow path is stopped before the start of power generation of the fuel cell. The temperature of the refrigerant in the lower portion of the refrigerant flow path is equal to or lower than a fourth threshold value, and the temperature of the refrigerant in the higher portion of the refrigerant flow path is equal to or lower than a fifth threshold value that is smaller than the fourth threshold value. In the case, the fuel cell system estimates the water state as a frozen state.

1 1. The fuel cell system according to any one of claims 1 to 3, wherein the storage device includes a discharge valve for discharging the water,

The fuel cell system further includes

A refrigerant flow path for flowing a refrigerant for cooling the fuel cell;

A valve temperature estimator for estimating the discharge valve temperature; A valve temperature storage unit that stores the discharge valve temperature estimated by the valve temperature estimation unit, and

The valve temperature estimation unit detects the refrigerant temperature at the start of power generation of the fuel cell, and detects the detected refrigerant temperature, and the discharge valve temperature stored in the valve temperature storage unit at the end of the previous power generation. A fuel cell system that estimates a lower temperature of the exhaust valve temperature at the start of power generation.

1 2. The fuel cell system according to claim 8 further includes:

A valve temperature estimator for estimating the discharge valve temperature;

A valve temperature storage unit for storing the discharge valve temperature estimated by the valve temperature estimation unit, and

1 3. The fuel cell system according to any one of claims 4 to 7 and 9 to 11 1.

The storage device includes a discharge valve for discharging the water,

The fuel cell system further includes

A valve temperature estimator for estimating the discharge valve temperature;

A valve temperature storage unit that stores the discharge valve temperature estimated by the valve temperature estimation unit, and

The valve temperature estimation unit detects the refrigerant temperature at the start of power generation of the fuel cell, and detects the detected refrigerant temperature, and the discharge valve temperature stored in the valve temperature storage unit at the end of the previous power generation. , Of the lower temperature at the start of power generation A fuel cell system that estimates the exhaust valve temperature.

1 4. In the fuel cell system according to any one of claims 11 to 13, when the valve temperature estimation unit newly estimates the exhaust valve temperature during power generation of the fuel cell, A fuel cell system that detects the refrigerant temperature and estimates the refrigerant temperature based on the detected refrigerant temperature and the previously estimated exhaust valve temperature.

1 5. The fuel cell system according to any one of claims 1 to 14, wherein the valve temperature estimation unit may cause the discharge valve to freeze based on the estimated discharge valve temperature. A fuel cell system that determines whether or not.

1 6. The fuel cell system according to claim 15 further comprises:

Equipped with a discharge valve freezing information storage unit,

When the valve temperature estimation unit determines that the discharge valve may be frozen, the discharge valve freezing information storage unit indicates that the discharge valve may be frozen. Freezing possibility information Memorize the fuel cell system.

1 7. In the fuel cell system according to claim 16,

When the valve temperature estimation unit determines that the discharge valve is not likely to freeze, the discharge valve freezing information storage unit indicates that there is almost no possibility of the discharge valve freezing. A fuel cell system that stores release information.

18. The fuel cell system according to any one of claims 4 to 17, wherein the refrigerant flow path is formed in the fuel cell or in the vicinity of the fuel cell.