JP2009238561A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system having a heater for homogenizing temperature of fuel cells, which eliminates deterioration of performance of each fuel cell based on the fact that an electric current flows in each fuel cell being in a condition of uneven concentration of a reactant gas due to system halt. <P>SOLUTION: A fuel cell system is arranged to comprise: a fuel cell stack 10 having two heaters (or one heater) 13 for equalizing the temperatures of fuel cells 11; and two relays (or one relay) 17 having a normally-open contact. The system has a circuit formed for applying an output voltage of the fuel cell stack 10 to the heater 13 via the relays 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  The fuel cell stack has a configuration in which an end plate or the like is provided at each stacking direction end of a stack of fuel cells (hereinafter referred to as a stack). Therefore, in the fuel cell stack, the temperature of each fuel cell located on the end side of the stacked body tends to be low. When the temperature of some of the fuel cells is lowered, the power generation performance of the fuel cell stack is deteriorated. Therefore, the vicinity of the fuel cells that are likely to be lowered in temperature (perpendicular to the stacking direction of the stacked body). It has been proposed to provide a heater functioning on the side surface) based on the generated voltage of the fuel cell stack.

  Specifically, a fuel cell system (see Patent Document 1) shown in FIG. 3 has been proposed. The fuel cell stack 51 provided in this fuel cell system is configured such that a plurality of fuel cell rows 53 that are a stack of fuel cell cells are arranged so that the polarities of two adjacent fuel cell rows 53 are different. Further, the fuel cell stack 51 does not have a large amount of heat released from the left side in the figure.

  The fuel cell system is provided with a heater (resistive heating element) 54 for heating the end portions of each of the two fuel cell rows 53 in the fuel cell stack 51. The heater 54 (and fuse) is connected to the output terminals of the two fuel cell rows 53 in order to eliminate the need for the power supply for the heater 54.

  If such a configuration is adopted, the temperature of each fuel cell in the fuel cell stack (fuel cell array 53) can be controlled to be substantially the same. However, if the above configuration is adopted as it is, after the fuel cell system is stopped, current flows to each fuel cell in which the reaction gas concentration is in a non-uniform state due to the system stop, and as a result, The performance of the fuel cell may be deteriorated.

  Regarding the fuel cell stack, in addition to the above technique, a technique for discharging the fuel cell stack when the fuel cell stack is stopped (see, for example, Patent Document 2), and starting from a low temperature can be performed in a short time. Therefore, a technique using a heater (for example, see Patent Documents 3 to 5) is known.

JP-T-2006-513534 JP 2002-352840 A JP 2005-93282 A JP 2006-172967 A JP 2003-45462 A

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a heater for homogenizing the temperature of the fuel cell, so that the reaction gas concentration becomes non-uniform due to the system shutdown. An object of the present invention is to provide a fuel cell system in which the performance of each fuel cell does not deteriorate due to the current flowing through each fuel cell.

  In order to solve the above-described problem, the fuel cell system according to the first aspect of the present invention is configured such that a stacked body in which a plurality of fuel cells are stacked, and the stacked body can be heated from the side surface in the stacking direction of the fuel cells. A fuel cell stack including a heater disposed and two output terminals for outputting a voltage generated by the laminated body to the outside; a relay means having a normally open contact; and a relay means to close the normally open contact Control means for controlling, and when the relay means, the two output terminals of the fuel cell stack, and the heater, the voltage from the two output terminals is applied to the heater only when the normally open contact of the relay means is closed. As such, it has an electrically connected configuration.

  That is, the fuel cell system according to the first aspect of the present invention is a heater for uniformizing the temperature of the fuel cells (a heater arranged so that the stacked body can be heated from the side surface in the stacking direction of the fuel cells). In addition, the output voltage of the fuel cell stack (laminated body) is applied via a relay means having a normally open contact. The relay means having a normally open contact is always opened when the system is stopped. Therefore, this fuel cell system is provided with a heater for equalizing the temperature of the fuel cell, and a current flows through each fuel cell in which the reaction gas concentration is in a non-uniform state due to the system shutdown. This is a system in which the performance of each fuel cell does not deteriorate.

  In realizing the fuel cell system according to the first aspect of the present invention, the fuel cell stack includes first and second heaters arranged so that the stacked body can be heated from each side surface in the stacking direction of the fuel cells. It is also possible to connect the heaters, the relay means, and the fuel cell stack (laminate) in a daisy chain. However, when such a configuration is adopted, when one heater is cut off, the function of the other heater is also stopped. And, since the power generation efficiency of the fuel cell stack is better in the state where the heating by one heater is performed than in the state where the heating by the heater is not performed at all, the case where the fuel cell stack having the above configuration is adopted Employs means having first and second normally open contacts as relay means, and means for controlling the relay means so that both the first and second normally open contacts are closed as control means. The first heater and the first normally open contact of the relay means connected in series between the two output terminals of the fuel cell stack, and the second heater and the second normally open contact of the relay means. It is desirable to connect them in series.

  The fuel cell system according to the second aspect of the present invention includes a stack in which a plurality of fuel cells are stacked, a heater disposed so that the stack can be heated from the side surface in the stacking direction of the fuel cells, A fuel cell stack including two main output terminals for outputting the voltage generated by the stacked body to the outside, and a secondary output terminal provided between specific fuel cells in the stacked body, and a normally open contact Relay means, and control means for controlling the relay means so that the normally open contact is closed. The relay means, one main output terminal of the fuel cell stack, the sub output terminal, and the first and second heaters are connected to each other. Only when the normally open contact of the means is closed, the voltage is electrically connected so that the voltage from the one main output terminal and the sub output terminal is applied to the first and second heaters. Have.

That is, in this fuel cell system, a heater that is arranged so that the stack can be heated from the side in the stacking direction of the fuel cells, and a percentage of the output voltage of the fuel cell stack (stack) has a normally open contact. It has the structure applied through the relay means which has. Therefore, this fuel cell system also includes a heater for equalizing the temperature of the fuel cell, and current flows through each fuel cell in which the reaction gas concentration becomes non-uniform due to the system shutdown. Thus, the system does not deteriorate the performance of each fuel cell. Further, since the output of the fuel cell stack is not directly applied to the relay means (normally open contact), this fuel cell system can improve the durability of the system / relay means that can use an inexpensive relay means. It becomes a system.

  When realizing the fuel cell system of the second aspect of the present invention, the first and second heaters arranged so that the stack can be heated from each side in the stacking direction of the fuel cells as the fuel cell stack. In addition, the heater, the relay means, and a part of the laminate (the part from which the generated voltage can be taken out by one main output terminal and the sub output terminal) can be connected in a daisy chain. . However, when the fuel cell stack having such a configuration is adopted for the reason already described, means having first and second normally open contacts are adopted as the relay means, and the first and second as the control means. A means for controlling the relay means so that both of the second normally open contacts are closed is adopted, and the first heater and the first of the relay means are provided between one main output terminal and the sub output terminal of the fuel cell stack. It is desirable to connect the normally open contact of the first heater and the normally connected contact of the second heater and the second normally open contact of the relay means in series.

  According to the present invention, a current flows through each fuel cell that is provided with a heater for equalizing the temperature of the fuel cell and in which the reaction gas concentration is in a non-uniform state due to system shutdown, It is possible to provide a fuel cell system in which the performance of the fuel cell does not deteriorate.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

<< First Embodiment >>
Hereinafter, the configuration and operation of the fuel cell system according to the first embodiment of the present invention will be described with reference to FIG. The fuel cell system according to this embodiment has been developed as a fuel cell system for a fuel cell vehicle (a power supply system for a vehicle motor).

  As shown in the drawing, the fuel cell system according to the present embodiment includes a fuel cell stack 10, a fuel cell stack part composed of two relays 17 and two fuses 18, a gas / cooling water supply mechanism 20, ECU (electronic control unit) 30 is provided.

  First, the configuration and function of the fuel cell stack unit will be described.

  Each relay 17 used in the fuel cell stack unit is a mechanical relay having a normally open contact. Note that the normally open contact point is a contact set (make contact, a contact, etc.) that is normally open and is closed during operation (when the coil is excited or externally controlled). That is).

  In the fuel cell stack 10, a terminal 16, a heater 13, an insulator 14, and an end plate 15 are attached to each side in the stacking direction of a stack 12 in which a plurality of fuel cells 11 are connected in series so that a high voltage can be obtained. Unit. That is, the fuel cell stack 10 has a configuration in which two heaters 13 (specifications will be described later) are added to a fuel cell stack having a general configuration.

As shown in the drawing, one power supply terminal of each heater 13 in the fuel cell stack 10 is connected to one terminal 16 of the fuel cell stack 10. The other power supply terminal of each heater 13 and the other terminal 16 of the fuel cell stack 10 are connected via a relay 17 and a fuse 18 (by connecting the relay 17 and the fuse 18 in series).

  In short, in the fuel cell stack unit, if the fuel cell stack 10 performs a power generation operation in a state where each fuse 18 is not blown and each relay 17 is operating, each fuel cell stack 10 is connected to each heater 13. Each component is connected so that the output voltage (voltage between the two terminals 16) of the stack 10 (laminate 12) is applied.

  The fuel cell stack unit according to the present embodiment has the above-described configuration, and as each heater 13, a predetermined voltage (in this embodiment, the maximum of the fuel cell stack 10 in the state) is applied to the fuel cell stack 10 in the above state. When the output voltage is continuously output, a heater having a specification in which the temperature of each fuel battery cell 11 becomes substantially equal is adopted. In addition, the fuel cell stack unit employs a relay with a breakdown voltage higher than the maximum output voltage of the fuel cell stack 10 as each relay 17, and the fuse 18 is blown when a short circuit occurs in the heater 13. A fuse whose rated voltage is higher than the maximum output voltage of the fuel cell stack 10 is also adopted.

  Next, the configuration and functions of the gas / cooling water supply mechanism 20 and the ECU 30 included in the fuel cell system according to the present embodiment will be described.

  The gas / cooling water supply mechanism 20 is a mechanism for supplying anode gas (hydrogen gas), cathode gas (air), and cooling water to the fuel cell stack 10. This gas / cooling water supply mechanism 20 is composed of a hydrogen tank, an air compressor, a gas-liquid separator, a cooling water circulation pump, a cooler, various valves and the like, in the same manner as a general gas / cooling water supply mechanism. It has become.

  The ECU 30 is basically a unit having the same function and configuration as an existing ECU (for fuel cell control). That is, the ECU 30 is a unit that controls each part (valve or the like) in the gas / cooling water supply mechanism 20 so that the output voltage of the fuel cell stack 10 (voltage between the terminals 16) becomes the target voltage. The ECU 30 is a unit composed of a CPU, a ROM, a RAM, and the like, and a unit that supplies power necessary for its operation from a battery (not shown) via an ignition switch (not shown) (turns off the ignition switch). In this case, the unit stops operating.

  However, the ECU 30 starts the operation of each relay 17 when starting the control of the gas / cooling water supply mechanism 20 (when the fuel cell stack 10 starts a power generation operation). It is configured as a unit that terminates the operation of each relay 17 when the control is terminated (when the fuel cell stack 10 terminates the power generation operation). More specifically, the ECU 30 includes a relay control terminal 30a connected to the coil of each relay 17, and is a unit that changes the voltage level of the relay control terminal 30a at the above timing.

  As described above, in the fuel cell system according to the present embodiment, the output voltage of the fuel cell stack 10 (stacked body 12) is always open to each heater 13 for equalizing the temperature of the fuel cell 11. It has the structure applied through the relay 17 which has a contact. Since the relay 17 having the normally open contact is always opened when the system is stopped, the fuel cell system according to this embodiment includes the heater 13 for equalizing the temperature of the fuel cell 11. In addition, the system does not deteriorate the performance of each fuel cell 11 due to the current flowing through each fuel cell 11 whose reaction gas concentration is in a non-uniform state due to the stop of the system. Become.

<< Second Embodiment >>
Hereinafter, the configuration and function of the fuel cell system according to the second embodiment of the present invention will be described with reference to FIG. In addition, detailed description is abbreviate | omitted about each component (each component which attached | subjected the same referential mark) as the fuel cell system which concerns on 1st Embodiment of the fuel cell system which concerns on this embodiment. I will decide.

  As shown in the figure, the fuel cell system according to the present embodiment includes a fuel cell stack unit including a fuel cell stack 10 ′, two relays 17 ′, and two fuses 18 ′.

  Each relay 17 ′ used in the fuel cell stack portion is a mechanical relay having a normally open contact, like the relay 17 described above. However, each relay 17 ′ has a lower withstand voltage than the relay 17 (details will be described later).

  The fuel cell stack 10 ′ is a unit in which a terminal 16, a heater 13 ′, an insulator 14, and an end plate 15 are attached to each side surface of the stacked body 12 in the stacking direction. The heater 13 ′ used in the fuel cell stack 10 ′ has a smaller resistance value between power terminals than the heater 13 (details will be described later).

  Further, the fuel cell stack 10 ′ has a sub-terminal 19 for taking out a power generation voltage by a part of the fuel cell groups 11 in the stack 12 between two specific fuel cells 11 in the stack 12. It is an attached unit. Hereinafter, the voltage that can be taken out by the sub-terminal 19 and the terminal 16 on the left side in the figure is referred to as a heater heating voltage.

  As is clear from the figure, the fuel cell stack unit performs a power generation operation on the fuel cell stack 10 'in a state where each fuse 18' is not blown and each relay 17 'is operating. In other words, the components are connected so that the heater heating voltage is applied to each heater 13 '.

  In short, the fuel cell stack portion is configured such that the voltage applied to each heater 13 'is lower than that of the fuel cell stack portion according to the first embodiment. In addition, since the fuel cell stack unit is configured as described above, the fuel cell stack unit operates the relays 17 'as the heaters 13' and operates the fuel cell stack 10 'with a predetermined voltage (as in the first embodiment). When the output of the same voltage is continued, the fuel cell 11 has a specification in which the temperature of each fuel cell 11 is substantially equal (that is, a resistance value between power supply terminals smaller than that of the heater 13). . Further, the fuel cell stack portion employs a relay with a breakdown voltage slightly higher than the heater heating voltage (a breakdown voltage lower than that of the relay 17) as each relay 17 ', and a heater 13 as each fuse 18'. A fuse having a specification suitable for '(a fuse whose rated voltage and rated current are different from those of the fuse 18) is adopted.

  As described above, the fuel cell system according to this embodiment also has a configuration in which voltage application to each heater 13 'is performed via each relay 17' having a normally open contact. Therefore, this fuel cell system also includes a heater 13 ′ for equalizing the temperature of the fuel cell 11, and the current is supplied to each fuel cell 11 in which the reaction gas concentration becomes non-uniform due to the system shutdown. This is a system in which the performance of each fuel battery cell 11 is not deteriorated by flowing.

  Furthermore, the configuration of the fuel cell system according to the present embodiment is such that the output voltage of the fuel cell stack 10 'is not directly applied to the relay 17'. Therefore, it can be said that this fuel cell system has a configuration in which an inexpensive relay 17 'can be used or a durability of the relay 17' can be improved.

<Deformation>
The fuel cell system according to the first and second embodiments described above can be variously modified. For example, the fuel cell stack portion according to each embodiment can be modified into one in which the two heaters 13 (13 ′) of the fuel cell stack 10 (10 ′) are connected in series.

  However, if two heaters 13 (13 ') are connected in series, when one heater 13 (13') is cut off, the other heater 13 (13 ') also stops functioning. On the other hand, if the configuration of each of the above-described embodiments is employed, even if one heater 13 (13 ') is cut off, the other heater 13 (13') is caused to function with the same amount of heat generation as before. It will be possible. The power generation efficiency of the fuel cell stack 10 (10 ') is greater when one heater 13 (13') is functioning than when both heaters 13 (13 ') are not functioning. Therefore, it is desirable to adopt the configuration of each embodiment.

  In addition, the fuel cell system according to each embodiment is a fuel cell stack 10 (10 ′) having a configuration in which the heat radiation amount only on one side in the stacking direction of the stacked body 12 (12 ′) is large, and in the stacking direction. The fuel cell stack 10 (10 ') provided with the heater 13 (13') can be modified only to the side surface.

  The fuel cell system according to each embodiment can be modified into a system in which the control of the relay 17 (17 ′) is performed by a circuit different from the ECU 30. Further, the fuel cell system according to each embodiment is configured so that the temperature of the fuel cell 11 at the end of the stacked body 12 and the temperature of the fuel cell 11 at the center of the stacked body 12 are equal. The system can be modified to a system including an ECU 30 that performs ON / OFF control of 17 ′). Further, in the fuel cell system according to each embodiment, the relay 17 (17 ′) uses a semiconductor relay instead of a mechanical relay, or two normally open contacts instead of the two relays 17 (17 ′). Needless to say, the relay may be changed to one using one relay.

1 is a configuration diagram of a fuel cell system according to a first embodiment of the present invention. It is a block diagram of the fuel cell system which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the existing fuel cell system provided with the heater for equalizing the temperature of a fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,10 '... Fuel cell stack 11 ... Fuel cell 12 ... Laminated body 13, 13' ... Heater 14 ... Insulator 15 ... End plate 16 ... Terminal 17, 17 '... Relay 18, 18' ... Fuse 19 ... Sub-terminal 20 ... Gas / cooling water supply mechanism 30a ... Relay control terminal 30 ... ECU

Claims (4)

A laminate in which a plurality of fuel cells are laminated, a heater disposed so that the laminate can be heated from the side surface in the lamination direction of the fuel cells, and a voltage generated by the laminate is output to the outside A fuel cell stack including two output terminals of
Relay means having normally open contacts;
Control means for controlling the relay means so that the normally open contact is closed,
The voltage from the two output terminals is applied to the heater only when the normally open contact of the relay means is closed between the relay means, the two output terminals of the fuel cell stack, and the heater. A fuel cell system characterized by being electrically connected. The fuel cell stack is
It includes first and second heaters arranged so that the stack can be heated from each side in the stacking direction of the fuel cells,
The relay means,
Means having first and second normally open contacts;
The control means is
Means for controlling the relay means such that both the first and second normally open contacts are closed;
Between the two output terminals of the fuel cell stack, the first heater and the first normally open contact of the relay means connected in series, the second heater and the second of the relay means The fuel cell system according to claim 1, wherein the normally open contact point is connected in series. A laminate in which a plurality of fuel cells are laminated, a heater arranged so as to heat the laminate from the side surface in the lamination direction of the fuel cells, and a voltage generated by the laminate to be output to the outside A fuel cell stack including two main output terminals and a sub output terminal provided between specific fuel cells in the stack;
Relay means having normally open contacts;
Control means for controlling the relay means so that the normally open contact is closed,
The relay means, the one main output terminal of the fuel cell stack, the sub output terminal, and the first and second heaters only when the normally open contact of the relay means is closed. A fuel cell system, wherein the fuel cell system is electrically connected so that a voltage from a main output terminal and the sub output terminal is applied to the first and second heaters. The fuel cell stack is
It includes first and second heaters arranged so that the stack can be heated from each side in the stacking direction of the fuel cells,
The relay means,
Means having first and second normally open contacts;
The control means is
Means for controlling the relay means such that both the first and second normally open contacts are closed;
The first heater and the first normally open contact of the relay means connected in series between the one main output terminal and the sub output terminal of the fuel cell stack, and the second The fuel cell system according to claim 3, wherein a heater and the second normally open contact of the relay means connected in series are connected.

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