JP2006004737A - Voltage measurement apparatus and fuel cell equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage measurement device which is superior in connection workability to a target to be measured and can be downsized. <P>SOLUTION: The voltage measurement device 1 is pressed and mounted to a side face perpendicular to the laminating face of a fuel cell laminate 8. The voltage measurement device 1 is provided with a conductive member 3 formed on an insulating substrate 2 as linear wiring, the insulating member 4 to cover the wiring except the tip of the wiring of the conductive member 3, a conductive elastic member 5 arranged and installed at the tip of the conductive member 3, and outside wiring 6 connected to the end of the side opposite to the tip of the conductive member 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a voltage measuring apparatus suitable for a fuel cell and a fuel cell including the same.

  A unit cell (cell), which is a basic unit of a polymer electrolyte fuel cell, sandwiches a membrane electrode assembly in which an anode side electrode and a cathode side electrode are formed on both sides of a polymer electrolyte membrane by a separator having a gas supply groove. It is comprised by doing. Usually, since the power generation voltage of a cell is as low as about 1 [V], the polymer electrolyte fuel cell is used as a fuel cell stack in which a predetermined number of cells are stacked.

  In this fuel cell stack, the fuel gas (hydrogen-containing gas) supplied to the anode-side electrode is hydrogen-ionized on the catalyst electrode and moves to the cathode-side electrode side through an appropriately humidified electrolyte membrane. Electrons generated in the meantime are taken out to an external circuit and used as direct current electric energy. Since the cathode side electrode is supplied with an oxidant gas, for example, an oxygen-containing gas or air, the hydrogen ions, the electrons, and the oxygen gas react with each other to generate water at the cathode side electrode.

  The fuel cell measures the voltage for each cell or a plurality of cells, confirms whether the fuel cell is operating normally, and adjusts the flow rate of the fuel gas and oxidant gas according to the voltage. In such a fuel cell voltage measuring apparatus, the voltage is measured by fitting a measuring terminal into a hole or indentation provided in the separator.

  As a terminal structure for measuring the cell voltage of a fuel cell, a voltage measuring device having a plurality of contact terminals in parallel with the stacking direction of the fuel cell stack is disclosed (Patent Document 1).

This voltage measuring device for a fuel cell is provided with a comb-like support plate having teeth at the same pitch as the cell interval of the fuel cell stack, and an L-shaped terminal pin on each tooth of the support plate. A terminal engaging hole is provided in the end face of the separator for each cell of the fuel cell stack, and the tip of each terminal pin is engaged in this hole to ensure the connection between the cell and the terminal.
JP 2002-124285 A (3rd page, FIG. 1)

  However, the above conventional fuel cell voltage measuring device secures an electrical connection by fitting the measuring terminal into a hole or a recess provided in the separator, so that the workability is ensured because the terminal pin is fitted into each separator. In addition, there is a problem in that an extra space must be provided in the case for housing the fuel cell in order to route the electric wire for wiring from the terminal pin.

  In order to solve the above problems, the present invention forms a wiring using a conductive material on an insulating substrate, and covers the wiring using a non-conductive substance except for the tip of the wiring. Then, the voltage measuring device is characterized in that a conductive elastic member is disposed at a tip portion of the wiring, and the conductive elastic member and a measurement target can be electrically connected.

  The present invention also includes the voltage measuring device, wherein each of the conductive elastic members of the voltage measuring device is pressed against one of the anode separators and cathode separators of each cell constituting the fuel cell stack. It is a fuel cell.

  According to the voltage measuring device of the present invention, the electrical connection with the measuring object is established simply by pressing the conductive elastic member at the tip of the wiring formed on the substrate against the measuring object. Even if there is a slight misalignment in the laminated surface of the body, the elasticity of the conductive elastic member absorbs the unevenness due to this misalignment and can be easily connected to the connecting surface perpendicular to the laminated surface. is there.

  According to the fuel cell of the present invention, the fuel cell is provided with the voltage measuring device, and each of the conductive elastic members of the voltage measuring device presses against one separator of the anode or the cathode of each cell constituting the fuel cell stack. Thus, there is an effect that the voltage measuring device can be easily connected to the fuel cell stack.

  Embodiments of a voltage measuring device and a fuel cell including the same according to the present invention will be described below with reference to FIGS.

  1A and 1B are a plan view and a cross-sectional view showing Example 1 of a voltage measuring apparatus according to the present invention. FIG. 2 is a schematic cross-sectional view of a fuel cell including the voltage measuring device according to the first embodiment. FIG. 3 is a plan view showing Embodiments 2 and 3 of the voltage measuring apparatus according to the present invention. 4A is a plan view showing Example 4 of the voltage measuring apparatus according to the present invention, and FIG. 4B is an exploded view showing a pattern example of the conductive member in Example 4. FIG. FIG. 5 is a schematic cross-sectional view showing another embodiment of the fuel cell according to the present invention.

  The voltage measuring apparatus 1 according to the first embodiment shown in FIG. 1 includes an insulating substrate 2, a conductive member 3 formed as a wire in a line on the insulating substrate 2, and a tip of the wiring of the conductive member 3. It consists of an insulating member 4 covering the wiring and a conductive elastic member 5 disposed at the tip of the conductive member. The external wiring 6 is brazed or connected to the end of the conductive member 3 on the insulating substrate 2 opposite to the tip by brazing, electric welding, conductive adhesive, or the like. The external wiring 6 is a wiring for connecting to a voltage measuring device such as a voltmeter.

  The insulating substrate 2 is made of an insulating film such as polyimide or polycarbonate, or an insulating plate material such as paper base phenolic resin or glass cloth base epoxy resin. On the insulating substrate 2, a conductive member 3 such as copper or silver is linearly applied, pasted, plated, or evaporated to form a wiring. The insulating member 4 is applied, affixed, plated or vapor-deposited except for the tip of the conductive member 3.

  Moreover, in order to form the wiring of the conductive member 3 on the insulating substrate 2, a known printed wiring board technique may be used. In this case, it is more preferable that a connector connected to the wiring is mounted on the printed wiring board, and the external wiring is detachably connected to the printed wiring board by the second connector fitted to the connector.

  A contact portion is formed at the distal end portion of the conductive member 3 by a conductive elastic member 5 having electrical conductivity and elasticity. The conductive elastic member 5 is made of carbon felt, metal particles, conductive rubber mixed with conductive particles such as carbon particles, conductive plastic mixed with these conductive particles, or a metal spring.

  FIG. 2 is a cross-sectional view of an essential part for explaining the outline of the fuel cell including the voltage measuring device shown in FIG.

  In FIG. 2, a fuel cell stack (fuel cell stack) 8 includes current collecting plates 9 and 10 at both ends where a large number of unit fuel cells (cells) 7 are stacked, and end plates 11 and 12 on the outside thereof. It arrange | positions and the pressure is applied to the lamination direction with the clamping member which is not shown in figure in the whole this laminated body. The unit fuel cell 7 includes a membrane electrode assembly 7b in which an anode side electrode and a cathode side electrode are formed on both surfaces of an electrolyte membrane using a solid polymer electrolyte, and an anode gas diffusion (not shown) outside the membrane electrode assembly. A layer and a cathode gas diffusion layer are disposed, and an anode separator 7a and a cathode separator 7c are further laminated on the outside thereof.

  The anode separator 7a has a gas supply groove (not shown) for supplying an anode gas containing hydrogen to the anode of the unit fuel cell 7, and the anode separator 7c (the cathode separator 7c ( In the case of a unit fuel cell at the end of the stack, it has conductivity so as to be transmitted to the current collector plate 10).

  The cathode separator 7c includes a gas supply groove (not shown) for supplying a cathode gas containing oxygen to the cathode of the unit fuel cell 7, and the anode separator 7a ( In the case of a unit fuel cell at the end of the stack, it has conductivity so as to be transmitted to the current collector plate 9).

  The side surfaces of the anode separator 7a and the cathode separator 7c of each unit fuel cell 7 are exposed on a surface perpendicular to the stack surface of the fuel cell stack 8 (hereinafter referred to as a stack side surface). The voltage measuring device 1 of Example 1 is attached to the side surface of the laminate while being pressed by a fixture (not shown).

  The state shown in FIG. 2 shows the voltage measuring device 1 that detects the potential difference between the potential of the anode separator 7a of the unit fuel cell 7 and the potential of the cathode separator 7c. The voltage measuring device 1 is pressed and electrically connected to the separator stack surface to be measured of the fuel cell stack 8.

  The voltage measuring device 1 includes two conductive elastic members 5 and 5 ′, conductive members 3 and 3 ′ connected thereto, and external wirings 6 and 6 ′ connected to the conductive members 3 and 3 ′, respectively. It has.

  The conductive elastic member 5 is connected to the cathode separator 7c 'of the unit fuel cell 7' adjacent to the anode separator 7a (upward in the figure). The range to which the conductive elastic member 5 is connected may be the range from the anode separator 7a to the cathode separator 7c '. The side surfaces of the membrane electrode assemblies 7b, 7b ', 7b "are insulative, and there is no problem even if the conductive elastic members 5, 5' are in contact with each other.

  The conductive elastic member 5 'is connected to the anode separator 7a "of the unit fuel cell 7" adjacent to the cathode separator 7c (downward in the figure). The range to which the conductive elastic member 5 ′ is connected may be the range from the cathode separator 7 c to the anode separator 7 a ″.

  According to the present embodiment, the conductive elastic members 5, 5 ′ of the voltage measuring device 1 are pressed and connected to the fuel cell stack 8, so that the mounting surface of the voltage measuring device 1 of the fuel cell stack 8. Even if there is a slight unevenness on the surface, and even if the members constituting the fuel cell stack 8 are expanded or contracted, it is possible to prevent the conductive elastic members 5 and 5 ′ from being displaced from the separator to be measured. is there.

  Further, since the voltage measuring device 1 can be wired to the fuel cell by applying the voltage measuring device 1 to the side surface of the fuel cell stack 8 as shown in FIG. 2, it is easy to attach the terminal to the separator, and the voltage measuring device can be downsized. effective.

  Next, a second embodiment of the voltage measuring apparatus according to the present invention will be described. The embodiment 1 shown in FIGS. 1 and 2 is an embodiment provided with a pair of measurement terminals. However, the embodiment 2 has a plurality of measurement terminal pairs as one insulating substrate as shown in FIG. An example of the voltage measuring device formed above is shown. The members constituting the voltage measuring device and the structure of the fuel cell stack to be measured are the same as those in the first embodiment shown in FIGS. Thus, duplicate description is omitted.

  As shown in FIG. 3A, the voltage measuring apparatus of this embodiment includes a plurality (three in the figure) of measuring terminal pairs 21 and 22, 23 and 24, 25 and 26 on one insulating substrate 2. They are arranged in parallel. Thereby, the potential differences V1, V2, and V3 between the separators can be measured for each of the plurality of unit fuel cells to be measured using one voltage measuring device.

  According to the present embodiment, even when measuring the voltages of a plurality of unit fuel cells, since a plurality of pairs of terminals are created and integrated on one insulating substrate, the workability of attaching the voltage measuring device is good. In addition, since there is no need to bundle wires, the voltage measuring device can be miniaturized.

  Next, Embodiment 3 of the voltage measuring device according to the present invention will be described with reference to FIG. As shown in FIG. 3 (b), the voltage measuring device of Example 3 is configured to measure a pair of measuring terminals so as to measure a potential difference between one current collector plate (equivalent to 9 or 10 in FIG. 2) and each unit cell. 21, 31, 22, 32, 23 and 33 are formed on one insulating substrate 2. Other configurations are the same as those of the second embodiment. In this embodiment, the voltage appearing at each terminal pair is V, V-V1, V-V1-V2,..., Where V is the total voltage of the stack, and from the difference, the voltage of each unit fuel cell to be measured, V1, V2,... Can be calculated.

  According to the present embodiment, since a plurality of terminal pairs are created in parallel on the insulating substrate 2, there is no need to bundle or fix the wires, the thickness of the voltage measuring device can be reduced, and compared with the line. Since the degree of integration can be increased, a large number of wires can be formed in a limited area, and the voltage measuring device can be reduced in size.

  FIG. 4A is a plan view for explaining a fourth embodiment of the voltage measuring apparatus according to the present invention, and FIG. 4B is a pattern diagram of the conductive member in the fourth embodiment. In this embodiment, the wiring pattern of the conductive member on the insulating substrate is meandered. Since other configurations are the same as those of the second embodiment shown in FIG. 3A, the same components are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 4B, even when the wiring pattern of the conductive member 3 is meandered, even if the ambient temperature of the voltage measuring device 1 changes or the voltage measuring device 1 expands and contracts due to an external force applied, Expansion and contraction of the elastic member 3 is absorbed by the meandering portion. Accordingly, the stress acting between the insulating substrate 2 and the conductive member 3 is reduced, and the possibility that the conductive member 3 is peeled off from the insulating substrate 2 or is broken can be reduced.

  According to this embodiment, since the wiring by the conductive member on the insulating substrate is meandering, even if the insulating substrate or the conductive member is deformed due to temperature change or external force, the wiring is deformed at the meandering portion of the wiring of the conductive member. Therefore, there is an effect that it is possible to provide a highly reliable voltage measuring device by suppressing the possibility of peeling of the conductive member from the insulating substrate and disconnection of the conductive member.

  FIG. 5 is a schematic cross-sectional view for explaining another embodiment of the fuel cell according to the present invention. In FIG. 5, the structure of the fuel cell stack 8 is the same as the structure of the fuel cell stack 8 shown in FIG. 2 except that the stack side surface insulating member 13 is added. Are given the same reference numerals, and redundant description is omitted.

  Although the present embodiment is not particularly limited, an embodiment of a fuel cell including a voltage measuring device 41 for measuring the voltages of two unit fuel cells 7 and 7 connected in series is shown.

  On the side surface of the fuel cell stack 8, for each of the two unit fuel cells, the paired side surfaces of the cathode separator 7c and the anode separator 7a that are adjacent to each other are insulated by sticking the stack side surface insulating member 13 in pairs. . As a material of the stack side surface insulating member 13, for example, a thin sheet of fluororesin such as polytetrafluoroethylene (PTFE) can be used.

  The stack side surface insulating members 13 may insulate the side surfaces of the fuel cell stack 8 with a plurality of strip-shaped sheets so as to cover a pair of the adjacent anode separator 7a and cathode separator 7c in pairs. However, it is also possible to use a single sheet with a hole only in a region facing the conductive elastic member 5 of the voltage measuring device 41.

  According to this embodiment, since the surface of each unit fuel cell facing the voltage measuring device of either the anode or the cathode is insulated by the insulating material, the voltage measuring device and the fuel cell stack are separated from each other. Even if the mutual position shifts, there is an effect that a short circuit between the anode and the cathode due to the conductive elastic member of the voltage measuring device can be prevented, and a highly reliable fuel cell can be provided.

(A) The top view explaining the structure of the voltage measuring device which concerns on this invention, (b) The same sectional drawing. 1 is a schematic cross-sectional view of a fuel cell including a voltage measuring device according to Example 1. FIG. (A) The top view explaining Example 2 of the voltage measuring device which concerns on this invention, (b) It is a top view explaining Example 3 of the voltage measuring device which concerns on this invention. (A) The top view explaining Example 4 of the voltage measuring device which concerns on this invention, (b) The top view which shows the wiring pattern example of the electroconductive member of Example 4. FIG. It is a schematic cross section explaining the other Example of the fuel cell which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Voltage measuring device 2 ... Insulating substrate 3 ... Conductive member 4 ... Insulating member 5 ... Conductive elastic member 6 ... External wiring 7 ... Unit fuel cell 8 ... Fuel cell laminated body

Claims (5)

  A wiring is formed using a conductive material on an insulating substrate, the wiring is covered with a non-conductive substance except for the tip of the wiring, and a conductive elastic member is provided at the tip of the wiring. A voltage measuring apparatus, characterized in that the voltage measuring apparatus can be disposed and electrically connected to the conductive elastic member and a measurement object.   The voltage measuring device according to claim 1, wherein a plurality of the wirings and the conductive elastic members are formed in parallel on the substrate.   The voltage measuring device according to claim 1, wherein the wiring on the substrate is meandering. A voltage measuring device according to any one of claims 1 to 3, comprising:
Each of the conductive elastic members of the voltage measuring device is pressed against a voltage measuring portion of the fuel cell stack.   The side surface of the fuel cell stack facing the voltage measuring device is covered with an insulating member except for the vicinity of the conductive elastic member of the voltage measuring device facing. Fuel cell.

Images