JP2007273433A - Cell unit, cell connection method, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cell unit capable of reducing contact resistance of connecting part when connecting electrically fuel battery cells by a connecting member. <P>SOLUTION: The cell unit is constructed by electrically connecting a plurality of fuel battery cells. Each fuel battery cell is provided with a first electrode extraction part having a first polarity and a second electrode extraction part having a second polarity, and has a connecting member 20 to connect electrically the first electrode extraction part on one side and the other second electrode extraction part of mutually adjoining two fuel battery cells, and connection of this connecting member 20 and the first electrode extraction part and the second electrode extraction part is carried out by resistance welding. It is preferable that a small projection 22b is formed at the portion of resistance welding of the connecting member 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cell unit configured by electrically connecting a plurality of fuel cells, a cell connection method, and a fuel cell.

  As a cell unit in which a plurality of fuel battery cells are electrically connected, a fuel battery disclosed in Patent Document 1 below is known. This fuel cell includes a coupling mechanism (corresponding to a connecting member) for coupling adjacent fuel cells among a plurality of flat plate fuel cells. This connection mechanism can perform electrical connection and mechanical connection by connecting electrodes of adjacent fuel cells. In addition, the coupling mechanism is configured to clamp the fuel cells by a pair of elastic clamping portions, and electrical connection is performed by the clamping force at that time.

JP 2005-268039 A

  However, when pinching is performed with a pinching portion having elasticity, the contact resistance increases, and a good electrical connection may not be obtained.

  The present invention has been made in view of the above circumstances, and the problem is that when the fuel cells are electrically connected to each other by a connection member, the cell unit, the cell connection method, and It is to provide a fuel cell.

In order to solve the above problems, the cell unit according to the present invention is:
A cell unit configured by electrically connecting a plurality of fuel cells,
Each fuel cell includes a first electrode extraction portion having a first polarity and a second electrode extraction portion having a second polarity,
A connection member for electrically connecting one first electrode extraction portion and the other second electrode extraction portion of two fuel cells adjacent to each other;
The connection member is connected to the first electrode extraction portion and the second electrode extraction portion by resistance welding.

  The operation and effect of the cell unit with this configuration will be described. This cell unit is configured by electrically connecting a plurality of fuel cells (unit cells). Each fuel cell includes a first electrode extraction portion having a first polarity and a second electrode extraction portion having a second polarity. For example, the first electrode extraction portion is on the cathode side (positive electrode), and the second electrode extraction portion is on the anode side (negative electrode). When electrically connecting fuel cells adjacent to each other, the first electrode extraction portion of one fuel cell is connected to the second electrode extraction portion of the other fuel cell. In this case, since the connection between each electrode extraction portion and the connection member is performed by resistance welding, the contact resistance can be extremely reduced. As a result, when the fuel cells are electrically connected to each other by the connecting member, it is possible to provide a cell unit that can reduce the contact resistance of the connecting portion as much as possible.

  In the connection member according to the present invention, it is preferable that a small protrusion is formed in a portion where resistance welding is performed. By forming such small protrusions, the energy at the time of resistance welding can be concentrated on the small protrusions, and the internal components constituting the fuel cell can be protected from heat.

In the present invention, the shape of the fuel cell is formed in a flat plate shape, and a plurality of fuel cells are arranged in a plane, and the first electrode extraction portion of each fuel cell is located on the front side, and the back side Arranged so that the second electrode extraction portion is located in
The connection member is processed into a substantially Z shape in a side view, a first connection portion that is resistance-welded to the first electrode extraction portion, a second connection portion that is resistance-welded to the second electrode extraction portion, and these It is preferable that the connecting portion that connects the connecting portions is integrally formed.

  According to this configuration, the connection member has the first connection portion, the coupling portion, and the second connection portion formed integrally, and has a substantially Z shape in a side view. Therefore, coupled with the fuel cell being formed in a flat plate shape, the entire unit can be reduced in thickness and size.

In order to solve the above problems, a cell connection method according to the present invention includes:
A cell connection method for electrically connecting a plurality of fuel cells,
Each fuel cell includes a first electrode extraction portion having a first polarity and a second electrode extraction portion having a second polarity,
When the first electrode extraction portion and the other second electrode extraction portion of two fuel cells adjacent to each other are electrically connected by the connecting member, resistance welding is performed.

  The operation and effect of the cell connection method having such a configuration is as described above.

  A preferred embodiment of a cell unit according to the present invention will be described with reference to the drawings. First, the structure of the fuel cell (unit cell) which comprises a cell unit is demonstrated with reference to FIG. 1, FIG. FIG. 1 is an assembled perspective view showing an example of a unit cell, and FIG. 2 is a longitudinal sectional view of the fuel cell shown in FIG.

<Configuration of fuel cell>
As shown in FIGS. 1 to 2, the fuel cell of the present invention includes a plate-shaped solid polymer electrolyte 1 and a cathode-side electrode plate 2 (first electrode) disposed on one side of the solid polymer electrolyte 1. And an anode side electrode plate 3 (corresponding to a second electrode plate) disposed on the other side. Further, a cathode side metal plate 4 (corresponding to a first metal plate) and an anode side metal plate 5 (second metal plate) are provided on the outer side of these electrode plates 2 and 3. In this embodiment, a fuel flow channel 9 is formed in the anode-side metal plate 5 by etching, and the peripheral portions of the anode-side metal plate 5 and the cathode-side metal plate 4 are made thinner than other portions by etching. Here is an example. Further, the cathode-side metal plate 4 constitutes a first electrode extraction part, and the anode-side metal plate 5 constitutes a second electrode extraction part.

  The solid polymer electrolyte 1 may be any solid polymer membrane battery as long as it is used in conventional solid polymer membrane batteries. From the viewpoint of chemical stability and conductivity, a perfluorocarbon having a sulfonic acid group which is a super strong acid. A cation exchange membrane made of a polymer is preferably used. Nafion (registered trademark) is preferably used as such a cation exchange membrane. In addition, for example, a porous film made of a fluororesin such as polytetrafluoroethylene impregnated with the above Nafion or other ion conductive material, a porous film made of a polyolefin resin such as polyethylene or polypropylene, or a non-woven fabric. A material carrying Nafion or another ion conductive material may be used. The thinner the solid polymer electrolyte 1 is, the more effective it is to make the whole thinner. However, in consideration of ion conduction function, strength, handling property, etc., 10 to 300 μm can be used, but 25 to 50 μm is preferable. .

  Electrode plates 2 and 3 (gas diffusion plates) that function as gas diffusion layers are used to supply and discharge fuel gas, oxidant gas, and water vapor, and at the same time collect electricity it can. As the electrode plates 2 and 3, the same or different ones can be used, and it is preferable to support a catalyst having an electrode catalytic action on the base material. The catalyst is preferably supported at least on the inner surfaces 2 b and 3 b in contact with the solid polymer electrolyte 1.

  As the electrode base material, for example, conductive carbon materials such as carbon paper, fibrous carbon such as carbon fiber nonwoven fabric, and aggregates of conductive polymer fibers can be used. In general, the electrode plates 2 and 3 are prepared by adding a water-repellent substance such as a fluororesin to such a conductive porous material. When the catalyst is supported, a catalyst such as platinum fine particles and fluorine It is formed by mixing a water-repellent substance such as a resin, mixing it with a solvent to form a paste or ink, and then applying this to one side of an electrode substrate that should face the solid polymer electrolyte membrane. The

  In general, the electrode plates 2 and 3 and the solid polymer electrolyte 1 are designed according to the reducing gas and the oxidizing gas supplied to the fuel cell. In the present invention, it is preferable to use air as the oxidizing gas and hydrogen gas as the reducing gas. In addition, methanol, dimethyl ether, or the like can be used instead of the reducing gas.

  For example, when hydrogen gas and air are used, the cathode side electrode 2 on the side where the air is naturally supplied causes a reaction between oxygen and hydrogen ions, so that water is generated. Is preferred. In particular, under the operating conditions of low operating temperature, high current density, and high gas utilization rate, the electrode porous body is likely to be clogged (flooded) due to the condensation of water vapor, particularly at the air electrode where water is generated. Therefore, in order to obtain stable characteristics of the fuel cell over a long period of time, it is effective to ensure the water repellency of the electrode so that the flooding phenomenon does not occur.

  As the catalyst, at least one metal selected from platinum, palladium, ruthenium, rhodium, silver, nickel, iron, copper, cobalt and molybdenum, or an oxide thereof can be used. A supported one can also be used.

  The thickness of the electrode plates 2 and 3 is more effective for reducing the overall thickness as the thickness is reduced, but is preferably 50 to 500 μm in view of electrode reaction, strength, handling properties, and the like. The electrode plates 2 and 3 and the solid polymer electrolyte 1 may be laminated and integrated in advance by adhesion, fusion, or the like, or may simply be arranged in a stacked manner. Such a laminated body can also be obtained as a thin film electrode assembly (MEA), and may be used.

  A cathode side metal plate 4 is disposed on the surface of the cathode side electrode plate 2, and an anode side metal plate 5 is disposed on the surface of the anode side electrode plate 3. The anode side metal plate 5 is provided with a fuel inlet 5c and a discharge port 5d, and further, in the present embodiment, a flow channel 9 is provided in the anode side metal plate 5.

  The cathode side metal plate 4 is provided with a large number of opening holes 4c for supplying oxygen in the air. As long as the cathode side electrode plate 2 can be exposed, the number, shape, size, formation position, and the like of the opening 4c may be any. However, in consideration of the supply efficiency of oxygen in the air and the current collection effect from the cathode side electrode plate 2, the area of the opening 4c is preferably 10 to 50% of the area of the cathode side electrode plate 2, In particular, 20 to 40% is preferable. As for the opening hole 4c of the cathode side metal plate 4, for example, a plurality of circular holes or slits may be provided regularly or randomly, or the opening hole may be provided by a metal mesh.

  As the metal plates 4 and 5, any metal can be used as long as it does not adversely affect the electrode reaction, and examples thereof include stainless steel plates, nickel, copper, and copper alloys. However, from the viewpoint of elongation, weight, elastic modulus, strength, corrosion resistance, press workability, etching workability and the like, a stainless steel plate, nickel and the like are preferable.

  The channel groove 9 provided in the anode side metal plate 5 may have any planar shape or cross-sectional shape as long as a channel for hydrogen gas or the like can be formed by contact with the electrode plate 3. However, in consideration of the channel density, the lamination density at the time of lamination, the flexibility, etc., it is preferable to mainly form the vertical groove 9a parallel to one side of the metal plate 5 and the vertical groove 9b. In this embodiment, a plurality of (three in the illustrated example) vertical grooves 9a are connected in series to the horizontal grooves 9b to balance the flow path density and the flow path length.

  A part of the channel groove 9 (for example, the lateral groove 9b) of the metal plate 5 may be formed on the outer surface of the electrode plate 3. As a method of forming the flow channel groove on the outer surface of the electrode plate 3, a mechanical method such as heating press or cutting may be used. However, it is preferable to perform groove processing by laser irradiation in order to perform fine processing suitably. From the viewpoint of performing laser irradiation, the base material for the electrode plates 2 and 3 is preferably an aggregate of fibrous carbon.

  One or a plurality of inlets 5c and outlets 5d communicating with the channel groove 9 of the metal plate 5 can be formed. In addition, although the thickness of the metal plates 4 and 5 is more effective for reducing the overall thickness as the thickness is reduced, 0.1 to 1 mm is preferable in consideration of strength, elongation, weight, elastic modulus, handling property, and the like. Etching is preferable as a method of forming the flow channel 9 in the metal plate 5 in view of processing accuracy and ease. In the channel groove 9 by etching, a width of 0.1 to 10 mm and a depth of 0.05 to 1 mm are preferable. The cross-sectional shape of the channel groove 9 is preferably substantially square, substantially trapezoidal, substantially semicircular, V-shaped or the like.

  Etching is also preferably used for forming the opening hole 4 c in the metal plate 4, thinning the peripheral portion of the metal plates 4, 5, and forming the inlet 5 c to the metal plate 5. Etching can be performed using, for example, a dry film resist or the like, after forming an etching resist having a predetermined shape on the metal surface, and then using an etching solution corresponding to the type of the metal plates 4 and 5. Moreover, the cross-sectional shape of the flow-path groove | channel 9 can be controlled more precisely by performing a selective etching for every metal using the laminated board of 2 or more types of metals.

  The embodiment shown in FIG. 2 is an example in which the caulking portions (peripheral portions) of the metal plates 4 and 5 are thinned by etching. In this way, the caulking portion is etched to have an appropriate thickness, whereby sealing by caulking can be performed more easily. From this viewpoint, the thickness of the crimped portion is preferably 0.05 to 0.3 mm.

  In the present invention, the peripheral edges of the metal plates 4 and 5 are sealed by caulking (corresponding to press bending) in an electrically insulated state. Electrical insulation can be performed by interposing the insulating material 6, the peripheral edge of the solid polymer electrolyte 1, or both. In the present invention, when caulking is performed, as shown in FIG. 4, a structure in which the solid polymer electrolyte 1 is sandwiched between the peripheral edges of the metal plates 4 and 5 is preferable, and the solid polymer electrolyte 1 is sandwiched while the insulating material 6 is interposed. More preferable is the structure. According to such a structure, inflow of gas or the like from one of the electrode plates 2 and 3 to the other can be effectively prevented. The thickness of the insulating material 6 is preferably 0.1 mm or less from the viewpoint of thinning. In addition, it is possible to further reduce the thickness by coating the insulating material (for example, the insulating material 6 can have a thickness of 1 μm).

  As the insulating material 6, a sheet-like resin, rubber, thermoplastic elastomer, ceramics, and the like can be used. However, in order to improve the sealing performance, resin, rubber, thermoplastic elastomer, and the like are preferable, and in particular, polypropylene, polyethylene, polyester, fluorine Resin and polyimide are preferable. The insulating material 6 can be integrated with the metal plates 4 and 5 in advance by sticking or coating the peripheral edges of the metal plates 4 and 5 directly or via an adhesive.

  As the caulking structure, the structure shown in FIG. 2 is preferable from the viewpoint of sealing performance, ease of manufacture, thickness, and the like. That is, the peripheral region 5a of one metal plate 5 is made larger than the peripheral region 4a of the other, and the peripheral region 5a of one metal plate 5 is replaced with the peripheral region 4a of the other metal plate 4 while the insulating material 6 is interposed. A caulking structure that is folded back so as to sandwich pressure is preferable. In this caulking structure, it is preferable to provide a step in the peripheral region 4a of the metal plate 4 by pressing or the like. Such a caulking structure itself is known as metal processing, and can be formed by a known caulking device.

  In FIG. 2, a metal pin 5 e for joint is attached to the metal plate 5 at the inlet 5 c. This attachment can be performed by caulking or press fitting. The metal pipe 10 can be press-fitted and attached to the pin 5e. A gas supply flow path can be formed by further inserting the resin pipe 11 into the metal pipe 10 (see also the exploded perspective view of FIG. 2B). The same configuration can be adopted for the outlet 5d.

  Further, as shown in FIG. 2, the metal plates 4 and 5 are formed with protrusions 4f and 5f, and the electrode plates 2 and 3 are formed in the space formed inside these protrusions 4f and 5f. Be contained. The protrusions 4f and 5f can be formed by drawing (punching) the metal plates 4 and 5.

<Configuration of cell unit>
Next, the configuration of the cell unit will be described with reference to FIG. FIG. 3 is an exploded perspective view of the cell unit. FIG. 4 is a side view of the assembled cell unit. The cell units are connected by connecting three fuel cells in series. However, the number of connected fuel cells is not limited to this and can be an appropriate number.

  A connecting member 20 is provided to connect fuel cells adjacent to each other. The connecting member 20 is manufactured by pressing a metal plate. The connecting member 20 includes a first connecting portion 21 connected to the protruding portion 4f (first electrode extraction portion) of one adjacent fuel cell, and a protruding portion 5f (second electrode extraction) of the other adjacent fuel cell. The second connecting part 22 connected to the connecting part) and the connecting part 23 connecting the connecting parts 21 and 22 are integrally formed. The shape of the connecting member 20 is substantially Z-shaped in a side view shown in FIG. Thereby, the whole cell unit can be reduced in thickness and size.

  The connecting portion 21 includes an extending portion 21a that extends in the direction of the protruding portion 4f, and the connecting portion 22 also includes an extending portion 22a that extends in the direction of the protruding portion 5f. Further, small projections 21b and 22b projecting toward the projecting portions 4f and 5f are formed on the connection portions 21a and 22a, respectively. And the connection member 20 is connected with each protrusion part 4f, 5f by resistance welding using this small protrusion 21b, 22b. Resistance welding is a method of welding using heat generated by energizing a portion to be welded, and can be performed by a predetermined resistance welder. By connecting by such resistance welding, the connection member 20 and each fuel cell can be electrically connected in a state where the contact resistance is as small as possible. Therefore, good electrical characteristics can be maintained even after the fuel cells are connected. In addition, by performing resistance welding with the small protrusions 21b and 22b, energy can be concentrated locally and the solid polymer electrolyte 1 and the like inside the fuel cell can be prevented from being damaged by heat.

  The specific shape of the small protrusions 21b and 22b can be, for example, about φ3 mm and the protruding height can be about 200 μm. As the material of the connection member 20, for example, stainless steel can be used, and the surface can be subjected to treatment such as plating as necessary. The number and size of the small protrusions 21b and 22b can be appropriately changed as necessary.

<Another configuration of cell unit>
Next, another configuration of the cell unit will be described with reference to FIG. The difference from FIG. 4 is that the connection member 20 is not provided with small protrusions 21b and 22b. When performing resistance welding, the welding areas 21c and 22c set in advance are welded by a predetermined resistance welding machine. The area of the welding areas 21c and 22c may be a minute area similar to the case where the small protrusions are provided. Moreover, the pulse shape of the voltage applied when performing resistance welding is shown in FIG. As shown in FIGS. 6A and 6B, a pulsed voltage pulse is applied. (A) has a slightly gentle rise and rise shape, while (b) has a sharp rise and fall shape, and (b) is more efficient in resistance welding and a fuel cell. It is preferable in view of thermal damage to the cell. If the time of the section t ₁ where the voltage value is maximum is set to about several msec (2 to 5 msec), resistance welding can be reliably performed, and the influence of thermal damage to the fuel cell does not occur.

The characteristics when the fuel cells were actually connected by resistance welding shown in FIG. 5 were experimentally confirmed. The experimental results are shown in FIG. In addition, the thing of the external appearance structure shown in FIG. 8 was used for the fuel cell. The horizontal axis represents current density (mA / cm ² ), and the vertical axis represents voltage (V) and output density (mW / cm ² ). In the figure, the case of resistance welding is compared with the case of an evaluation jig. Here, the configuration of the evaluation jig is shown in FIG.

  In FIG. 8, the fuel cell is connected to the circuit board 30 by a frame-shaped pressing portion 31. A first pattern 30a and a second pattern 30b are formed on the circuit board 30, and the cathode-side metal plate 4 and the first pattern 30a are connected via a metal frame-shaped pressing portion 31, and the cathode-side metal plate. 5 and the second pattern 30 b are connected by a pressing force by the frame-shaped pressing portion 31. The frame-shaped pressing part 31 is formed with a coupling hole 31a, and is connected to the circuit board 30 by a screw. Thereby, electrical connection is reliably performed. Adjacent fuel cells are electrically connected via a circuit board pattern.

  As shown in FIG. 7, the electrical characteristics when the fuel cells are connected by resistance welding are almost the same as those of the evaluation jig shown in FIG. 8, and it was confirmed that the desired characteristics could be secured. In the case of the evaluation jig, the circuit board 30 is required on the back surface of the fuel cell, but when connecting by resistance welding, the circuit board 30 can be omitted. Therefore, in the case of cell units connected by resistance welding, it is possible to reduce the size.

<Usage example of cell unit>
Next, an actual usage example of the cell unit will be described with reference to FIGS. FIG. 9 illustrates an example in which four fuel cells are connected and used as a detachable fuel cell. This detachable fuel cell can be used as a driving power source or a charging power source for a notebook computer, a portable device (PDA, mobile phone, etc.) and the like. FIG. 10 is an exploded view of the fuel unit before assembly.

  As shown in FIG. 10, the four fuel cells S are electrically and mechanically connected by the connection member 20. As described above, the connecting member 20 is connected to the fuel cell S by resistance welding. As shown in the drawing, two welding areas 22c are provided in a spot manner. Two connecting members 20 are used to connect the adjacent fuel cells S, but the number is not particularly limited to two. Although not shown in FIG. 10, the connection between the connecting member 20 and the cathode side metal plate 4 is performed by the same method as that for the anode side metal plate 5. In addition, it is arbitrary whether or not the small protrusion is provided on the connecting member 20 in order to perform resistance welding.

  A metal pipe 10 is press-fitted into the metal booth 5 e, and the flow path grooves 9 of the adjacent fuel cells S are connected by a resin pipe 11. In the configuration example shown in FIG. 10, the channel groove 9 is formed by a metal stamping press process, so that a protruding portion 5 g having the same shape as the channel groove 9 is formed on the outer surface of the anode side metal plate 5. It appears as

  The four fuel cells S can be assembled into a frame shape as shown in FIG. Since the fuel cells S can be connected to each other by the connecting member 20, it is not necessary to arrange a circuit board for attaching the fuel cells S inside the fuel cells S, and the size can be reduced. As shown in FIG. 10, a space having a substantially square cross section is formed inside the assembled cell unit, and the hydrogen gas generation unit 25 is inserted into this space. The hydrogen gas generation unit 25 is a unit that generates hydrogen gas by reacting, for example, powdered or tablet-like aluminum with water. The gas supply port 25 a of the hydrogen gas generation unit 25 is connected to the metallic pipe 10 of any one fuel cell S, and hydrogen gas is supplied to each fuel cell S.

  A circuit board 26 and a power supply terminal 27 are arranged at the end of the cell unit assembled in a frame shape. The circuit board 26 is mounted with a booster circuit or the like in order to obtain a voltage suitable for a device that supplies power. Further, of the four fuel cells S, a connecting arm 22 d extends to the connection member 20 connected to the fuel cell S located at the end, and this is connected to the circuit board 26. A lead wire may be used instead of the connecting arm 22d. The power supply terminal 27 is, for example, a USB terminal, but is not limited thereto. For example, a connector for charging a secondary battery disposed inside a mobile phone, a portable music player, or the like. It may be a terminal. The power supply terminal 27 is configured as a terminal that is detachable from the device.

  In the example of FIG. 9, four fuel cells S are used, but the number of cells is not limited to a specific numerical value. Further, when the fuel cell S is assembled into a frame shape, the anode side metal plate 5 is disposed outside, but the cathode side metal plate 4 is disposed outside and the air intake opening 4c is disposed on the surface side. Good. In FIG. 9, the anode side is located on the front side and the cathode side is located on the back side. As shown in FIG. 11, the cathode side is located on the front side and the anode side is located on the back side. Also good.

<Another embodiment>
The configuration of the fuel cell constituting the cell unit is not limited to that of the present embodiment, and various modifications are possible. For example, the planar shape of the fuel cell does not have to be a rectangle, and a square or other shapes can be adopted. In the present embodiment, the cathode side metal plate 4 has the air intake opening 4c. However, a fuel cell of a type in which the opening 4c is not formed may be used. The mode in which the fuel cells are arranged in a plane is not limited to the arrangement in the present embodiment, and various modifications are possible.

Assembly perspective view showing an example of the fuel battery cell of the present invention The longitudinal cross-sectional view which shows an example of the fuel battery cell of this invention Exploded perspective view showing the configuration of the cell unit Assembly side view showing the configuration of the cell unit Assembly side view showing another configuration of cell unit The figure which shows the shape of the voltage pulse applied at the time of resistance welding Graph showing experimental results Diagram showing the configuration of the evaluation jig Diagram showing usage example of cell unit The figure which shows the structural example of the cell unit in FIG. Diagram showing another example of using cell unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid polymer electrolyte 2 Cathode side electrode plate 3 Anode side electrode plate 4 Cathode side metal plate 5 Anode side metal plates 4f and 5f Protrusion part 20 Connection member 21 1st connection part 22 2nd connection part 23 Connection part 21a, 22a Extension Part 21b, 22b Extension part 21c, 22c Welding area

Claims (5)

A cell unit configured by electrically connecting a plurality of fuel cells,
Each fuel cell includes a first electrode extraction portion having a first polarity and a second electrode extraction portion having a second polarity,
A connection member for electrically connecting one first electrode extraction portion and the other second electrode extraction portion of two fuel cells adjacent to each other;
A cell unit characterized in that the connection member is connected to the first electrode extraction portion and the second electrode extraction portion by resistance welding.   The cell unit according to claim 1, wherein a small protrusion is formed on the connection member at a portion where resistance welding is performed. The fuel cell is formed in a flat plate shape, and a plurality of fuel cells are arranged in a plane, and the first electrode extraction portion of each fuel cell is located on the front side, and the second electrode on the back side. It is arranged so that the take-out part is located,
The connection member is processed into a substantially Z shape in a side view, a first connection portion that is resistance-welded to the first electrode extraction portion, a second connection portion that is resistance-welded to the second electrode extraction portion, and these The cell unit according to claim 1 or 2, wherein a connecting portion that connects the connecting portions is integrally formed. A cell connection method for electrically connecting a plurality of fuel cells,
Each fuel cell includes a first electrode extraction portion having a first polarity and a second electrode extraction portion having a second polarity,
A cell connection method characterized by performing resistance welding when electrically connecting one first electrode extraction portion and the other second electrode extraction portion of two fuel cells adjacent to each other by a connecting member.   A fuel cell comprising the cell unit according to claim 1, a hydrogen gas generation unit for supplying hydrogen gas to the cell unit, and a power supply terminal for supplying electric power generated by the cell unit to an apparatus.

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