JP4484196B2 - Fuel cell condition monitoring device - Google Patents

Description

  The present invention relates to a fuel cell state monitoring device that monitors the states of a plurality of cells that are connected in series to form a fuel cell stack.

  Fuel cells are attracting attention as a power source for various devices and equipment because they have no pollution and high efficiency. However, since the voltage of each cell is relatively low, it is usually used as a stack in which a plurality of cells are connected in series. When a predetermined voltage cannot be obtained in the stack, it is considered that a failure (voltage is lower than a predetermined value) has occurred in any cell. Various monitoring techniques have been developed to find failed cells.

For example, a conventional voltage monitoring device (see Patent Document 1) includes a plurality of A / D converters 104 connected to terminals of a plurality of cells of the stack 100 and connected in parallel to each other, as shown in FIGS. It comprises a plurality of auxiliary arithmetic units 103 that compare the detected cell voltage with a set value and output a control signal, and one main arithmetic unit 110 connected to the plurality of auxiliary arithmetic units. Each auxiliary arithmetic unit 103 connected in series to the load 107 includes a multiplexer 105 and a CPU 106 in addition to the A / D converter 104.
Japanese Patent Laid-Open No. 11-345622

  In the conventional voltage monitoring apparatus, each of the plurality of auxiliary arithmetic units 103 and the main arithmetic unit 110 are connected to each other by wires 108. That is, the same number of wirings 108 as the number of auxiliary arithmetic units 103 are used. As a result, not only the number of wirings 108 is increased and the component cost is increased, but also the connection work is complicated and the assembly cost is increased. Further, when the stack 100 reaches a high voltage, it is necessary to electrically insulate between the auxiliary arithmetic unit 103 and the wiring 108 as a countermeasure against withstand voltage. Therefore, the structure of the entire voltage monitoring device is complicated and expensive.

  The present invention has been made in view of the above circumstances, and an internal circuit having a processing unit that acquires and processes cell state information, and an external circuit that issues a detection command signal to the processing unit and receives cell state information from the processing unit It is an object of the present invention to provide a fuel cell state monitoring apparatus in which the transmission means between them is simplified.

The basic technical idea of the present invention is to perform signal transmission / reception between the internal circuit and the external circuit by wireless communication using a tag technology or the like. The fuel cell state monitoring device according to the present invention is a fuel cell state monitoring device that monitors the states of a plurality of cells that are connected in series to each other to form a stack of fuel cells, as described in claim 1. A plurality of boards mounted with a plurality of processing units that are attached to the stack and receive power from the stack to acquire and process cell state information and a plurality of transmission / reception circuits that output the state information received from each processing unit And a reader including an external circuit that outputs a detection command signal and is insulated from the substrate .

  This state monitoring device transmits the detection command signal output from the external circuit and the cell state information output from the transmission / reception circuit to the external circuit and the transmission / reception circuit, respectively, by wireless communication. That is, predetermined signals and information are transmitted (transmitted / received) via wireless communication between the transmission / reception circuits of the plurality of substrates attached to the stack and the external circuit of the reader.

  The applicant of the present application has previously filed a battery state monitoring device for a fuel cell stack in which signal transmission means between an internal circuit (auxiliary circuit) and an external circuit (main circuit) is simplified (Japanese Patent Laid-Open No. 2003). -243015). However, in this battery state monitoring device, the same number of substrates as the number of cells are provided, and it is difficult to say that it is easy to attach the substrates to the cells and mount internal circuits on the substrates.

  The fuel cell state monitoring apparatus according to claim 2 further includes a plurality of internal antennas connected to each of the transmission / reception circuits and an external antenna connected to the external circuit in claim 1, and includes a detection command signal and cell state information. And transmitted by radio waves via the internal antenna and the external antenna. According to a third aspect of the present invention, there is provided a fuel cell state monitoring apparatus according to the second aspect, wherein a module is formed by a plurality of cells, and a transmission / reception circuit is provided for each module.

  According to a fourth aspect of the present invention, there is provided the state monitoring apparatus for a fuel cell according to the third aspect, wherein a wireless tag having a transmission / reception circuit is mounted on a substrate, and the internal antenna is integrated with the wireless tag. According to a fifth aspect of the fuel cell state monitoring apparatus of the present invention, the detection command signal is transmitted simultaneously from the external circuit to the plurality of transmission / reception circuits, and the state information is sequentially transmitted from each transmission / reception circuit to the external circuit. According to a sixth aspect of the present invention, there is provided the fuel cell state monitoring device according to the fourth aspect, wherein the individual identification numbers of the modules are recorded in each of the transmission / reception circuits, and the arrangement order of the individual identification numbers is stored in the external circuit.

  According to the fuel cell state monitoring apparatus of the present invention, since predetermined signals and information are wirelessly communicated between the transmission / reception circuit and the external circuit, a part of wired communication means such as a harness for connecting the two becomes unnecessary. The transmission means becomes simple. According to the fuel cell state monitoring device of claim 2, since radio wave communication is performed between the internal antenna connected to the transmission / reception circuit and the external antenna connected to the external circuit, even if the distance between the two is slightly apart, Signals and information can be exchanged. According to the fuel cell state monitoring apparatus of claim 3, since the state information of all the cells can be acquired by the same number of substrates as the number of modules, the number of substrates can be reduced compared to the number of cells, and the state accordingly. The monitoring device becomes compact.

  According to the fuel cell state monitoring apparatus of the fourth aspect, the transmission / reception circuit is mounted on the wireless tag, and the internal antenna is connected thereto. By using a general-purpose wireless tag, the state monitoring device becomes inexpensive. According to the fuel cell state monitoring apparatus of the fifth aspect, it is possible to receive the state information of each cell at the same time, and it is possible to determine abnormality of all the cells under the same condition. According to the fuel cell state monitoring apparatus of the sixth aspect, the state information of each cell can be identified and received (without confusion), and the abnormal cell can be easily and reliably identified.

<Cell, status information>
The typical state information of the cell is its voltage value, but the state information is not limited to the voltage value. In the present invention, by using a dedicated sensor, the temperature, pressure, partial current, moisture content, internal magnetic flux density, and the like in the gas and cooling water in the cell can be detected and used for the control.
<Board>
The substrate includes a processing unit that acquires and processes cell state information, and a transmission / reception circuit that outputs the state information received from the processing unit. The processing unit can include a part for acquiring state information such as a cell voltage, a plurality of analog switches for switching cells, an A / D converter, and a CPU for processing data. The number of substrates can be equal to the number of modules comprising a plurality of cells, for example. Each of the plurality of substrates has a rectangular shape, and the width can correspond to the thickness of the module, for example. Attached to the surface of the module or embedded in the cell.

  In the present invention, at least a transmission / reception circuit circuit is mounted on a wireless tag described below. In a typical example, the transmission / reception circuit is mounted on the wireless tag, the processing unit is formed in a part different from the wireless tag on the substrate, and the driving power can be supplied from the module. Normally, the voltage of the cell is about 0.7V per sheet, and is 0.5V even if it is lowered. Therefore, for example, in a module in which five cells are stacked, a voltage of 2.5 V to 3.5 V is obtained, which is sufficient for driving the processing unit. However, the processing unit may be mounted on the wireless tag together with the transmission / reception circuit.

If the voltage transition and abnormal state of each cell are recorded in the memory of the CPU, it can be used for failure analysis. Further, by managing the manufacturing history at the time of manufacturing for each individual identification number of each module, it can be used for quality control of the module.
<Wireless tag>
The “wireless tag (IC tag)” is an electronic tag using a semiconductor chip that can exchange data wirelessly. Various explanations have been made on the wireless tag. In the present invention, the “wireless tag” means a transmission / reception circuit or the like excluding the internal antenna. The transmission / reception circuit and the like include a storage unit (memory) in addition to the transmission / reception circuit. The shape and size of the internal antenna can be determined in relation to the substrate and the module.

Note that an integrated structure in which a transmission / reception circuit and the like and an internal antenna are connected can be regarded as a wireless tag. However, the most important feature of the present invention is that wireless communication is performed between a transmission / reception circuit of a wireless tag attached to a module or the like and an external circuit of a reader, that is, between an insulated module and an external circuit. Even if the wireless tag on which the transmission / reception circuit or the like is mounted is separated from the internal antenna, even if the integrated structure of the transmission / reception circuit and the internal antenna is regarded as the wireless tag, this feature does not change.
<Reader>
The reader (reader) includes an external circuit and an external antenna. In the external circuit, the order of identifiable cells is recorded, and the order is stored when the modules are stacked, or the order is stored by arranging codes from a computer or the like separately connected to the external circuit. good. The external antenna performs radio communication with the internal antenna using radio waves as a medium. That is, when an antenna is connected to a wireless tag and brought close to a reader (reader), an electromotive force is generated on the wireless tag side by a radio wave (for example, 13.5 MHz radio wave) from the reader (the principle of electromagnetic induction). The transmission / reception circuit operates by this power, and data can be exchanged with an external reader. Therefore, the wireless tag does not require a power source and can be used semipermanently.

  Specifically, the external circuit simultaneously transmits a detection command signal to all the transmission / reception circuits, that is, the processing units via the external antenna and the internal antenna. In addition, the external circuit transmits cell state information sequentially generated by the transmission / reception circuit via the internal antenna and the external antenna. In this way, the module and the external circuit are insulated and exchange data by wireless communication via wireless or the like.

  In the present invention, “wireless communication” includes transmission of a signal by a magnetic field and transmission of a signal by electrostatic coupling, in addition to the communication by the radio wave (microwave). Communication using radio waves is suitable when the distance between the wireless tag and the external reader is long (for example, about several meters), and signal transmission by electrostatic coupling is suitable when the distance is short (for example, about several centimeters). Transmission of a signal by a magnetic field is suitable for the distance between the two. It is not essential to provide an internal antenna and an external antenna for transmission using a magnetic field or transmission using electrostatic coupling.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
(Constitution)
a. Fuel Cell FIGS. 1 and 2 show a fuel cell stack, a substrate, and the like. 1 is a front view, and FIG. 2 is a plan view. Each of the plurality of flat cells 10 of the fuel cell is provided with a positive electrode plate having a high potential and a negative electrode plate having a low potential with a solid electrolyte membrane interposed therebetween, and separators serving also as current collectors are provided on both sides thereof. ing. A hydrogen gas passage through which hydrogen gas flows and an air passage through which air flows are provided between the separator and these electrode plates.

Here, a module 12 is formed by five cells 10, and a stack 14 is formed by a plurality of modules 12. However, since the cell 10 itself is well-known, detailed description is abbreviate | omitted.
b. Voltage Monitoring Device FIGS. 2, 3 and 4 show a voltage monitoring device. FIG. 3 is an enlarged explanatory view of the substrate, the wireless tag, and the internal antenna, and FIG. 4 is a circuit explanatory view showing the relationship among the components of the voltage monitoring device. A substrate 20 is embedded in one corner of each module 12 shown in FIGS. The substrate 20 is rectangular and has a width approximately equal to the width of the module 12. Each substrate 20 includes a processing unit 22 and a wireless tag 30.

  As shown in FIGS. 3 and 4, the processing unit 22 includes five contact portions (not shown) that contact a part of each cell 10, five switches 23, an A / D converter 24, and a memory 27. CPU26 is included. A switch 23 is arranged in the wiring 29 extending from the contact portion to the processing portion 22. The wireless tag 30 includes a transmission / reception circuit 32 connected to the CPU 26. As shown in FIG. 3, a loop-shaped internal antenna 34 is formed in a polyimide plate 33 having a shape integrated with each substrate 20, and is connected to the wireless tag 30. The width of the loop of the internal antenna 34 (the horizontal dimension in FIG. 2) is approximately the same as the width of the module 12, and the length is slightly shorter than the length of the module 12.

In FIG. 4, the reader 40 includes an external circuit (cell monitoring ECU) 42 and a loop-shaped external antenna 44 connected thereto. As can be seen from FIG. 2, the loop width of the antenna 44 is approximately the same as the loop length of the internal antenna 34, and the length is approximately the same as the length of the stack 14. As a result, the short side portion of each internal antenna 34 and the long side portion of the external antenna 44 are close to each other in the space.
(Function)
Next, the operation (voltage monitoring method) of this embodiment will be described. First, detection command signals are simultaneously transmitted from the external circuit 42 of the reader 40 to all the modules 12 and transmitted to the transmission / reception circuit via the external antenna 44 and the internal antenna 32 connected to the wireless tag 30. As a result, the switch 23, the A / D converter 24, and the CPU 26 of each module 12 of the processing unit 22 simultaneously detect the voltage of each cell 10.

  Subsequently, the external circuit 42 assigns individual identification numbers in the order of arrangement of the modules 12 and issues a signal transmission command sequentially (with a time difference). For example, the module 12 at one end of the stack 14 is notified that it is the first. This is because, since the external circuit 42 and the module 12 communicate wirelessly, it is impossible to identify which module 12 the external circuit 40 is from unless the individual identification number is assigned.

The module 12 having the same individual identification number transmits the measured voltage values of the five cells 10 from the internal antenna 34 to the external circuit 42 via the external antenna 44. Similarly, the voltage value of the cell 10 of the other module 12 is transmitted. Therefore, transmission of voltage values from each module 12 to the external circuit 42 is performed sequentially. If there is an abnormality or failure (for example, the voltage value is lower than a predetermined value) in a specific cell 10, a necessary device is applied.
(effect)
According to this embodiment, the following effects can be obtained. First, the transmission means between the CPU 26 of the processing unit 22 corresponding to each module 12 and the external circuit 42 is simplified. As can be seen from FIG. 4, signals are transmitted and received between the CPU 26 and the external circuit 42 by the wireless tag 30, the internal antenna 34, and the external antenna 44, and no physical connection means such as a harness is required.

  Second, the external circuit 42 of the reader 40 can reliably identify which module 12 indicates the voltage value while the first effect is obtained. This is because the arrangement order of the individual identification numbers of the modules 12 is recorded in the external circuit 42. In this connection, voltage transition and history management of each module 12 is easy. This is because these are stored in the memory 27 of the CPU 26. Further, although there is a time difference in the signal from the transmission / reception circuit 32, there is no problem because the detection time of each module 12 is the same.

  Third, even if transmission / reception of signals between any of the processing units 22 and the external circuit 42 becomes impossible, transmission / reception of signals between the other processing units 22 and the external circuit 42 is not affected. This is because the external circuit 42 transmits information to and from each processing unit 22 independently.

  List other effects. First, since the five contact portions and the five switches 23 are provided on each substrate 20, the voltage values of all the cells 10 constituting each module 12 can be detected. Therefore, it is possible to quickly and reliably identify the abnormal cell 10 from among the many cells 10. Further, since the A / D converter 24 and the CPU 26 are driven by the power of the cell 10, it is not necessary to prepare a separate driving power source. Furthermore, since the module 12 and the external circuit 42 are insulated, it is not necessary to provide an insulating means between both ends of the external circuit 42.

  Note that the voltage monitoring apparatus of this embodiment does not simply apply a radio tag technology known in other fields to voltage detection of modules constituting a stack. The above various effects cannot be obtained from simple application of the wireless tag technology, and in particular, the technical significance of being able to eliminate the insulating means of the external circuit 42 is great.

It is a front view of a stack and a substrate of a fuel cell. It is also a plan view. It is an enlarged view of a board | substrate, a wireless tag, and an internal antenna. It is circuit explanatory drawing of the whole voltage monitoring apparatus. It is whole explanatory drawing of a prior art example. It is the principal part enlarged view similarly.

Explanation of symbols

10: Cell 12: Module 14: Stack 20: Substrate 22: Processing unit 26: CPU
30: Radio tag 32: Transmission / reception circuit 34: Internal antenna 40: Reader 42: External circuit 44: External antenna

Claims (6)

A fuel cell status monitoring device that monitors the status of a plurality of cells that are connected in series with each other to form a fuel cell stack,
A plurality of processing units mounted on the stack and supplied with electric power from the stack to acquire and process the status information of the cell and a plurality of transmission / reception circuits that output status information received from the processing units A substrate of
A reader that outputs a detection command signal and includes an external circuit insulated from the substrate ,
The detection command signal and the status information of the cell in which the transceiver circuit outputs, to transmit each to the transmission and reception circuit and said external circuit by wireless communication, a fuel cell state monitor, wherein the external circuit outputs . Furthermore, it includes a plurality of internal antennas connected to each of the transmission / reception circuits and an external antenna connected to the external circuit, and the detection command signal and the state information of the cell are transmitted via the internal antenna and the external antenna. The fuel cell state monitoring device according to claim 1, wherein the state is transmitted at a time.   The fuel cell state monitoring apparatus according to claim 2, wherein a module is formed by a plurality of the cells, and the transmission / reception circuit is provided corresponding to each module.   The fuel cell state monitoring device according to claim 3, wherein a wireless tag on which the transmission / reception circuit is formed is mounted on the substrate, and the internal antenna is integrated with the wireless tag.   5. The fuel cell state monitoring device according to claim 4, wherein the detection command signal is transmitted simultaneously from the external circuit to the plurality of transmission / reception circuits, and the state information is sequentially transmitted from the transmission / reception circuits to the external circuit.   The fuel cell state monitoring device according to claim 4, wherein the individual identification numbers of the modules are recorded in the transmission / reception circuits, and the arrangement order of the individual identification numbers is stored in the external circuit.

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