JP5923356B2 - Fuel cell device - Google Patents

Description

  The present invention relates to a fuel cell device.

  A fuel cell is a cell that can continuously take out electricity by exchanging fuel. In other words, the fuel cell does not require a charging operation like a secondary battery represented by a lithium ion battery in order to take out electricity, so there is no waiting time for charging, and no external power source such as an AC power source is required. . Therefore, the fuel cell is expected to be put to practical use as a new power source because of the convenience described above.

Here, the type of fuel cell is classified into a phosphoric acid type, a molten carbonate type, a solid oxide type, a solid polymer type, and the like depending on the electrolyte used. In particular, application of the polymer electrolyte fuel cell as a power source for small electronic devices is being studied.
Furthermore, it is classified into a passive type and an active type depending on the difference in the operation / operation method of the fuel cell.

  Passive type fuel cells perform fuel transfer and fuel generation control without using equipment called auxiliary equipment that operates by power consumption, such as pumps and solenoid valves. Efficient power generation can be expected (for example, see Patent Document 1).

  An active fuel cell uses an auxiliary device that requires a power source such as a pump or a blower to perform transportation of fuel, control of generation of fuel, and the like. That is, since the active fuel cell can control supply of a large amount of fuel compared to the passive type, it is possible to extract a large amount of power from the fuel cell. However, since the active fuel cell needs to send a large amount of fuel to the fuel cell in order to obtain high output from the fuel cell, the power consumption of auxiliary equipment such as a pump and a compressor increases. Therefore, a technique is known in which the energy loss of the auxiliary machinery at the time of high output of the fuel cell is reduced and the energy efficiency of the entire fuel cell device is improved (for example, see Patent Document 2).

JP 2011-146224 A JP-A-8-45525

However, the technique disclosed in Patent Document 2 does not give consideration to the power consumption of auxiliary equipment when the fuel cell has a low output. In particular, at the time of low output, the ratio of energy consumed by the auxiliary equipment to the output of the fuel cell increases, and there is a problem that the energy efficiency of the entire fuel cell device is lowered.
Therefore, the present invention has been made in view of the above-described problems, and the object thereof is to be stable without reducing the energy efficiency of the entire fuel cell device even when the power supply target is a low load. A fuel cell device capable of supplying electric power is provided.

  A first aspect of the present invention that achieves the above object is a fuel cell device that includes a fuel cell that generates electric power using supplied fuel, and that supplies the electric power generated by the fuel cell to an external load. An active fuel supply device that supplies fuel by an active method, a passive fuel supply device that supplies fuel to the fuel cell in a passive manner, and a fuel supply device that is both the active fuel supply device and the passive fuel supply device. A switching unit that switches the fuel supply device so that fuel is supplied from both or one of the fuel supply devices to the fuel cell, and an output state of the fuel cell device and switching control of the switching unit A state detection unit that performs the operation according to the detected output state, the switching unit to the fuel cell according to the detected output state And summarized in that switching the fuel supply device for supplying fuel.

Here, the fuel cell may be, for example, a SOFC (solid oxide fuel cell) in addition to a PEFC (solid polymer fuel cell) using hydrogen-oxygen as a fuel or a DMFC (direct methanol fuel cell) using methanol-oxygen as a fuel. Fuel cell), MCFC (molten carbonate fuel cell), PAFC (phosphoric acid fuel cell) and the like can be used.
The fuel may be any fuel that can be applied to the fuel cell. For example, in the case of PEFC, methanol or hydrogen may be used as the fuel. The fuel may be removed from the fuel cell and prepared as a replaceable cartridge.

The fuel cell device may be equipped with a voltage conversion device such as a DC-DC converter that converts the output of the fuel cell and supplies power to a load or the like in order to stabilize the output voltage. Furthermore, a power storage device such as a lithium ion secondary battery or a capacitor may be mounted as an output buffer of the fuel cell device.
According to this aspect, it is possible to select a fuel supply device that supplies fuel to the fuel cell according to the output state of the fuel cell.

According to a second aspect of the present invention, the state detection unit is consumed inside the fuel cell device, output power Pf of the fuel cell, supply power Po that the fuel cell device supplies to the external load, and the like. The gist is to detect an internal power consumption Pi, an active power consumption Pa consumed by the active fuel supply device, and a fuel supply device supplying fuel to the fuel cell.
According to this aspect, it is possible to grasp the output state of the fuel cell device and the fuel supply device that supplies fuel to the fuel cell.

According to a third aspect of the present invention, the state detection unit supplies fuel to the fuel cell by the switching unit when the ratio of the internal power consumption Pi to the output power Pf is greater than a predetermined value. The gist is to switch the fuel supply device to the passive fuel supply device.
According to this aspect, it is possible to avoid inefficient power generation in a state where the ratio of the power consumption Pi inside the fuel cell is high with respect to the output Pf of the fuel cell.

According to a fourth aspect of the present invention, when the state detection unit detects that the fuel supply device that supplies fuel to the fuel cell is a passive fuel supply device, the passive fuel supply device detects the fuel. When the ratio of the output power Pf to the power Pm when the fuel cell is generated with the maximum fuel supply amount that can be supplied to the battery exceeds a predetermined value, the switching unit causes the fuel cell to The gist of the present invention is to switch the fuel supply device that supplies fuel to the active fuel supply device.
According to this aspect, it is possible to avoid the power generation of the fuel cell in a fuel shortage state and to supply power stably.

A fifth aspect of the present invention includes an external state detection unit that detects an external state of the fuel cell device, and the state detection unit performs the switching according to the external state detected by the external state detection unit. The gist is to switch the fuel supply device for supplying fuel to the fuel cell by the unit.
According to this aspect, the fuel supply device of the fuel cell device can be controlled from the outside of the fuel cell device.

  According to a sixth aspect of the present invention, the external state detection unit can detect a driving state of the external load, and the state detection unit can detect whether the external load is in a sleep state or low power consumption by the external state detection unit. When it is detected that the fuel cell is in a state, the switching unit switches the fuel supply device that supplies fuel to the fuel cell to the passive fuel supply device.

According to a seventh aspect of the present invention, the external state detection unit can detect a fuel supply device selected by a user of the fuel cell device, and supplies fuel to the fuel cell by the switching unit. The gist is to switch the fuel supply device to the fuel supply device selected by the user.
According to this aspect, the user of the fuel cell device can arbitrarily select the fuel supply device.

  The fuel cell device according to the present invention includes an active fuel supply device and a passive fuel supply device, and the fuel cell device that supplies fuel to the fuel cell can be switched by the switching unit. Depending on the output state, the fuel supply device that supplies fuel to the fuel cell can be switched as necessary. Therefore, according to the fuel cell device according to the present invention, for example, even when the external load to which the fuel cell device supplies power is a low load, the passive fuel supply device that does not require the power consumption of the auxiliary equipment is used. Thus, the energy efficiency of the fuel cell device can be maintained.

  Therefore, the present invention can provide a fuel cell device that can stably supply power without lowering the energy efficiency of the entire fuel cell device, even when the power supply target is a low load. .

1 is a block diagram showing a configuration of a fuel cell device according to a first embodiment of the present invention. 2 is a flowchart showing a control procedure of the fuel cell device shown in FIG. 1. It is a block diagram which shows the structure of the fuel cell apparatus concerning 2nd Embodiment of this invention. It is a flowchart which shows the control procedure of the fuel cell apparatus shown in FIG.

Next, the present invention will be described in detail based on the embodiments shown in the drawings.
(First embodiment)
FIG. 1 shows an example of a fuel cell device according to a first embodiment of the present invention.
As shown in FIG. 1, the fuel cell device 1 includes a fuel cell 2, an active fuel supply device 3 and a passive fuel supply device 4 that supply fuel to the fuel cell 2, and a fuel supply target to the fuel cell 2. Is configured to include a fuel supply switching unit 5 that switches between the active fuel supply device 3 and the passive fuel supply device 4 and a state detection unit 6 that detects various states.

  The fuel cell 2 is a battery that generates power in accordance with the fuel supplied from the fuel supply switching unit 5. For example, the fuel cell 2 uses methanol as a negative electrode for supplying power via a state detection unit 6 to a load (external load) composed of electronic devices such as a notebook computer, a video camera, and a communication device. DMFC (direct methanol fuel cell) used as fuel. The fuel of the positive electrode is oxygen in the atmosphere, and the fuel cell 2 is configured to take in the atmosphere by natural intake. The fuel cell 2 is not limited to the DMFC, but in addition to PEFC (solid polymer fuel cell) using hydrogen as a negative electrode fuel, SOFC (solid oxide fuel cell), MCFC (molten carbon dioxide). A salt fuel cell), a PAFC (phosphoric acid fuel cell), and the like can be used as appropriate. The fuel may be prepared as a cartridge that can be removed from the fuel cell 2 and replaced.

  The active fuel supply device 3 is an active fuel supply device that supplies fuel (methanol) to the fuel cell 2 via the state detection unit 6 using auxiliary devices such as a pump, a valve, and a blower that consume power. . That is, since the active fuel supply device 3 can forcibly convey the fuel sealed in the container by the auxiliary machine, a large amount of fuel can be supplied, but the power consumption by the auxiliary machine increases. On the other hand, the passive fuel supply device 4 is a passive fuel supply device that supplies fuel to the fuel cell 2 via the state detection unit 6 without using the auxiliary device. Specifically, the passive fuel supply device 4 is configured to pressurize a plastic container filled with fuel from the outside with an elastic material such as a spring. Alternatively, by using a physical change such as an increase in pressure when the fuel is generated, the fuel such as hydrogen is used for a chemical reaction between the metal hydride and the aqueous solution. The fuel generation / supply control may be performed by injecting the aqueous solution by using a differential pressure between the pressure and the atmospheric pressure or by stopping the injection of the aqueous solution. Thus, while the passive fuel supply device 4 can supply fuel without power consumption, the fuel supply performance is inferior to the active fuel supply device 3.

  The fuel supply switching unit 5 (switching unit) has an input side connected to the active fuel supply device 3 and the passive fuel supply device 4, and an output side connected to the fuel cell 2. That is, the fuel supply switching unit 5 has a function of switching a fuel supply device for supplying fuel to the fuel cell 2 among the active fuel supply device 3 and the passive fuel supply device 4. When the fuel supply amount is insufficient with respect to the output of the fuel cell 2 or the power consumption of the load, the fuel supply switching unit 5 does not necessarily select only one fuel supply device, and the fuel cell from both fuel supply devices. Switching may be performed so that fuel can be supplied to the fuel cell 2. Further, switching by the fuel supply switching unit 5 is performed based on a switching signal transmitted from the state detection unit 6.

  The state detection unit 6 is connected to the fuel cell 2, the active fuel supply device 3, the fuel supply switching unit 5, and the load, and detects each electric power. Specifically, the state detection unit 6 is the output voltage Pf of the fuel cell 2, the supply power Po that is the power that the fuel cell device 1 supplies to the load, and the power that is consumed inside the fuel cell device 1. The internal power consumption Pi, the active power consumption Pa consumed by the active fuel supply device 3, and the output state of the fuel cell device 1 are detected. Here, the internal power consumption Pi indicates a difference amount between the output voltage Pf and the supply power Po. The active power consumption Pa indicates the power consumption of the auxiliary equipment provided in the active fuel supply device 3.

  Further, the state detection unit 6 determines whether the fuel supply device that supplies fuel to the fuel cell 2 from the fuel supply switching unit 5 is the active fuel supply device 3 or the passive fuel supply device 4. 1 is detected as an output state. Note that the maximum output power Pm that can be extracted from the fuel cell 2 when the fuel is supplied to the fuel cell 2 by the passive fuel supply device 4 is measured in a preliminary test using the state detection unit 6.

  Then, the state detection unit 6 performs switching control of the fuel supply switching unit 5. That is, the state detection unit 6 switches the fuel supply device that supplies fuel to the fuel cell 1 by the fuel supply switching unit 5 according to the detected output state.

  The fuel cell device 1 is equipped with a voltage converter (not shown) such as a DC-DC converter that converts the output of the fuel cell 2 and supplies power to a load or the like in order to stabilize the output voltage. Also good. Furthermore, a power storage device such as a lithium ion secondary battery may be mounted as a buffer for the output of the fuel cell device 1.

(Operation procedure of fuel cell device)
The operation of the fuel cell apparatus 1 configured as described above will be described with reference to the flowchart of FIG.
First, step S <b> 1 is a step of supplying fuel to the fuel cell 2 by the passive fuel supply device 4. Specifically, the state detection unit 6 performs control to switch the supply path to the passive fuel supply device 4 side by the fuel supply switching unit 5. As a result, the fuel cell 2 is supplied with fuel from the passive fuel supply device 4 and starts power generation. Here, in this step S1, the passive fuel supply device 4 is used for supplying fuel to the fuel cell 2 as an example, but the active fuel supply device 3 may be used. That is, the fuel supply switching unit 5 performs control to select either the active fuel supply device 3 or the passive fuel supply device 4 as appropriate according to the type of load, load characteristics, or the like, or as the specifications of the fuel cell device 1. It is good to do.

  Next, in step S2, the state detection unit 6 detects the output power Pf of the fuel cell 2 and the internal power consumption Pi consumed inside the fuel cell device 1, and the ratio of the internal power consumption Pi to be set to the output power Pf is determined in advance. It is determined whether or not a predetermined value (0.1 in this embodiment) is exceeded. Here, the state detection unit 6 detects a voltage value and a current value using a voltmeter and an ammeter (not shown) provided at the output terminal of the fuel cell 2, and multiplies the voltage value by the current value to obtain Pf. To detect. Similarly to Pf, the state detection unit 6 detects a voltage value and a current value from a voltmeter and an ammeter provided in front of the output end of the fuel cell device 1, and multiplies the voltage value by the current value. Then, Po, which is the power supplied from the fuel cell device 1 to the load, is calculated. Then, the state detection unit 6 detects Pi by subtracting Po from Pf. In addition, it is desirable to set the predetermined value so that the internal fuel loss and the output performance of the fuel cell and the system are not reduced by operating the passive fuel supply device 4 according to the system specifications. . The set value may be about 0.1 to 1, and is not limited to 0.1.

  In step S2, if the Pi / Pf calculation result is a value higher than 0.1 (step S2; Y), the process proceeds to step S4. Otherwise (step S2; N), the process proceeds to step S3. To do.

  When the process proceeds from step S2 to step S3, the state detection unit 6 switches the fuel supply to the fuel cell 2 from the passive fuel supply device 4 to the active fuel supply device 3 by the fuel supply switching unit 5, and the processing after step S2 is performed. repeat.

  When the process proceeds from step S <b> 2 to step S <b> 4, the state detection unit 6 causes the fuel supply switching unit 5 to supply fuel to the fuel cell 2 using the passive fuel supply device 4. That is, the state detection unit 6 supplies fuel by the active fuel supply device 3 in a state where the ratio of the internal power consumption Pi occupying the entire output power Pf is low (energy efficient state), while the internal power occupying the entire output power Pf When the ratio of the power consumption Pi increases, that is, when the ratio of the power consumption by the auxiliary equipment of the active fuel supply device 3 increases and the energy efficiency starts to decrease, the fuel by the passive fuel supply device 4 that does not use the auxiliary equipment By performing the supply, the energy efficiency of the fuel cell device 1 can be kept high.

  Subsequently, in step S5, the state detection unit 6 determines that the output power Pf when the passive fuel supply device 4 is supplying the fuel is the fuel supply amount that can be supplied to the maximum by the passive fuel supply device 4. Judgment is made so as not to exceed the power Pm when 2 generates power. This determination is made to prevent a situation in which the amount of fuel supplied to the fuel cell 2 falls short and the power supply to the load cannot be satisfactorily caused by Pf exceeding Pm. Here, after Pf exceeds Pm, the fuel supply to the fuel cell 2 is slow even if the switching from the passive fuel supply device 4 to the active fuel supply device 3 is performed. It is desirable to switch to the active fuel supply device 3 while the capacity is sufficient. In order to provide a surplus in the fuel supply capacity of the passive fuel supply device 4, it is only necessary to switch to the active fuel supply device 3 when Pf exceeds the output of about 80% of Pm. In the present embodiment, as an example, when the state detection unit 6 determines that Pf exceeds 90% of Pm (Pf / Pm> 0.9; a predetermined value), the process proceeds to step S3. Thus, the fuel supply switching unit 5 is switched from the passive fuel supply device 4 to the active fuel supply device 3.

  On the other hand, if the state detection unit 6 determines in step S5 that Pf is less than 90% of Pm, there is no need to switch the fuel supply device, and thus the processing from step S2 onward is repeated.

  In this way, the fuel cell device 1 according to the present embodiment switches to the fuel supply by the passive fuel supply device 4 even when the ratio of Pi that is set to Pf at a low load starts to increase. As a result, the energy efficiency of the fuel cell device 1 can be kept high. Further, the fuel cell device 1 switches the fuel supply to the fuel cell 2 to the active fuel supply device 3 in advance even if the output of the fuel cell 2 is likely to exceed the fuel supply capability of the passive fuel supply device 4. , Can supply power stably.

(Second Embodiment)
FIG. 3 shows the configuration of the fuel cell device according to the second embodiment of the present invention. Here, the fuel cell device 1a according to the present embodiment is different from the fuel cell device 1 according to the first embodiment in a state detection unit 6a and an external state detection unit 7a. In FIG. 2, the components other than the state detection unit 6a and the external state detection unit 7a are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof is omitted.

  In the fuel cell device 1a, the external state detection unit 7a is configured to detect an external state (described later) of the fuel cell device 1a, and the state detection unit 6a has a function of detecting power in each unit described in the first embodiment. In addition to the function of specifying the fuel supply device that supplies fuel to the fuel cell 2, it has a function of limiting the amount of power output to the load and a function of receiving a signal from the external state detection unit 7a.

  Here, the external state detection unit 7a is a load driving state (normal power consumption state, hibernation state, low power consumption state, etc.), and a method for supplying fuel to the fuel cell 2 arbitrarily by the user of the fuel cell device 1a. It is detected as an external state that any one of the active fuel supply device 3 and the passive fuel supply device 4 is selected. Here, when the user selects the passive fuel supply device 4, the passive fuel supply device 4 has no power driving parts such as an auxiliary machine and does not consume power when fuel is supplied. The advantage is that the power can be efficiently supplied and that the operation is extremely quiet with no noise or vibration.

(Operation procedure of fuel cell device)
The operation of the fuel cell apparatus 1a configured as described above will be described with reference to the flowchart of FIG.
First, step S1a is a step of supplying fuel to the fuel cell 2 by the passive fuel supply device 4 as in step S1 shown in FIG. Here, the passive fuel supply device 4 is used to supply fuel to the fuel cell 2. However, the active fuel supply device 3 may be used, and the specification of the fuel cell device 1 depends on the type of load and load characteristics. One of the active fuel supply device 3 and the passive fuel supply device 4 may be selected as appropriate.

  When fuel is supplied to the fuel cell 2 and the fuel cell 2 is generating power, in step S2a, the external state detection unit 6a externally detects the fuel cell 2 based on the external state detected by the external state detection unit 7a. When it is determined that the passive fuel supply device 4 is selected as the fuel supply to the battery, specifically, the load is in a dormant state or is set to a low power consumption state and does not require a large amount of power Or the user of the fuel cell device 1 manually selects the passive fuel supply device 3 (step S2a; Y), the fuel supply to the fuel cell 2 is performed via the fuel supply switching unit 5. The passive fuel supply device 4 is assumed (step S4a). On the other hand, when the external state detection unit 6a determines that the active fuel supply device 4 is selected as the fuel supply from the outside to the fuel cell 2 based on the external state detected by the external state detection unit 7a, Specifically, the load is set to a normal power consumption state and requires power, or the user of the fuel cell device 1a manually selects the active fuel supply device 4 In the case (step S2a; N), the fuel supply to the fuel cell 2 is made the active fuel supply device 3 through the fuel supply switching unit 5 (step S3a; N). And the external state detection part 6a repeats the process after step S2a, after the process of step S3a is complete | finished.

  Next, the state detection unit 6a determines whether or not the fuel cell output Pf is 90% or more of Pm in step S5a after the fuel supply to the fuel cell 2 is changed to the passive fuel supply device 4 in step S4a. to decide. Here, when the state detection unit 6a determines that Pf is less than 90% of Pm (step S5a; N), the process proceeds to step S2a. On the other hand, when Pf is 90% or more of Pm, the state detection unit 6a limits the output of the fuel cell 2 to the load so that the state detection unit 6 becomes less than 90% of Pm in Step S6a. After Pf becomes less than 90% of Pm, the process proceeds to step S2a.

  In this way, it is possible to stably supply power by interlocking with the state of the load, or by supplying fuel with high energy efficiency or high quietness in response to a user request.

DESCRIPTION OF SYMBOLS 1, 1a Fuel cell apparatus 2 Fuel cell 3 Active fuel supply apparatus 4 Passive fuel supply apparatus 5 Fuel supply switching part 6, 6a State detection part 7a External state detection part

Claims (6)

A fuel cell device that includes a fuel cell that generates power using supplied fuel, and that supplies power generated by the fuel cell to an external load,
An active fuel supply device that supplies fuel to the fuel cell in an active manner;
A passive fuel supply device for supplying fuel in a passive manner to the fuel cell;
Switching between the fuel supply devices connected to the fuel supply devices of both the active fuel supply device and the passive fuel supply device and switching the fuel supply device so as to supply fuel from both or one of the fuel supply devices to the fuel cell And
A state detecting unit that detects an output state of the fuel cell device and performs switching control of the switching unit;
With
The state detection unit switches a fuel supply device that supplies fuel to the fuel cell by the switching unit according to the detected output state, and further outputs an output power Pf of the fuel cell and the fuel cell device. Supply power Po supplied to the external load, internal power consumption Pi consumed inside the fuel cell device, active power consumption Pa consumed by the active fuel supply device, and fuel to the fuel cell A fuel cell device for detecting a fuel supply device. When the ratio of the internal power consumption Pi with respect to the output power Pf is greater than a predetermined value, the state detection unit replaces the fuel supply device that supplies fuel to the fuel cell by the switching unit. The fuel cell device according to claim 1 , wherein the fuel cell device is switched to. When the state detection unit detects that the fuel supply device that supplies fuel to the fuel cell is a passive fuel supply device, the state detection unit is configured to supply the maximum amount that the passive fuel supply device can supply to the fuel cell. A fuel supply device that supplies fuel to the fuel cell by the switching unit when the ratio of the output power Pf to the power Pm when the fuel cell is generated with the fuel supply amount exceeds a predetermined value the fuel cell system of claim 1 or 2, characterized in that switching to the active fuel supply device. An external state detection unit for detecting an external state of the fuel cell device;
Wherein the state detection unit, the in response to the external condition detected by the external condition detection unit, one of claims 1 to 3 to switch the fuel supply apparatus for supplying fuel to the fuel cell by the switching unit The fuel cell device according to one item. The external state detection unit can detect the driving state of the external load,
The state detection unit includes a fuel supply device that supplies fuel to the fuel cell by the switching unit when the external state detection unit detects that the external load is in a sleep state or a low power consumption state. The fuel cell device according to claim 4 , wherein the fuel cell device is switched to the passive fuel supply device. The external state detection unit can detect a fuel supply device selected by a user of the fuel cell device, and the user selects a fuel supply device that supplies fuel to the fuel cell by the switching unit. The fuel cell device according to claim 4 , wherein the fuel cell device is switched to a fuel supply device.

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