JP6950332B2 - How to assemble the cell monitor connector - Google Patents

Description

The present invention relates to a method of assembling a cell monitor connector for detecting and monitoring a cell voltage in a fuel cell.

For example, a cell of a solid polymer fuel cell (sometimes referred to as a fuel cell, a single cell, or a single cell) includes an ion-permeable electrolyte membrane, an anode-side catalyst layer (electrode layer) sandwiching the electrolyte membrane, and an electrode layer. A membrane electrode assembly (MEA) composed of a cathode side catalyst layer (electrode layer) is provided. Gas diffusion layers (GDL) are formed on both sides of the MEA to provide fuel gas or oxidant gas and to collect electricity generated by an electrochemical reaction. MEA in which GDL is arranged on both sides is called MEGA (Membrane Electrode & Gas Diffusion Layer Assembly), and MEGA is sandwiched by a pair of separators. Here, MEGA is the power generation unit of the fuel cell, and when there is no gas diffusion layer, MEA is the power generation unit of the fuel cell.

A fuel cell (sometimes referred to as a fuel cell stack) is constructed by stacking (stacking) a plurality of cells having the above-described configuration.

In a fuel cell, it is known to measure a cell voltage in order to monitor the power generation state of each stacked cell. Generally, when measuring the cell voltage, in the fuel cell stack assembly process, a cell monitor connector for cell voltage monitoring (hereinafter, simply referred to as simply) connected to the cell voltage monitoring device is connected to the detection terminal provided on the separator of each cell. Assemble the "connector").

The following methods are known as a method for assembling a connector in a conventional fuel cell. That is, as shown in FIG. 3, first, a plurality of cells constituting the fuel cell stack are laminated at predetermined intervals (for example, about 2 mm pitch) to form a fuel cell stack precursor (a laminate that is a base of the fuel cell stack). (Cell stacking process). The fuel cell stack precursor is then pressurized in the stacking direction, compressing and deforming the gas diffusion layer of each cell to narrow the spacing between the cells (eg, from about 2 mm pitch to about 1 mm pitch) (pressurization step). ). Next, the fuel cell stack precursor pressed and held is inserted into the stack case and fastened (insertion / fastening step). Then, the connector for cell voltage monitoring is inserted and connected between the detection terminals provided on the separator of each cell after the pressurization step and the insertion / fastening step (connector assembly step).

However, in the above-mentioned conventional assembling method, in the connector assembling step, the distance between adjacent cells (that is, between the detection terminals provided on the separators of adjacent cells) is narrow (for example, about 1 mm), and the connector is assembled. It took time to attach, and there was a possibility of misassembly.

In response to such a problem, in Patent Document 1, in order to improve the workability of assembling the connector to the detection terminal, a step of stacking a plurality of fuel cell cells provided with a detection terminal for detecting the cell voltage and the above-mentioned step. It has a step of inserting a connector for measuring a cell voltage between adjacent detection terminals and a step of pressing the stacked cells in a stacking direction to connect the detection terminal and the connector. A method has been proposed.

That is, in the technique described in Patent Document 1, the influence of the cell pitch is affected by inserting the connector between the adjacent detection terminals after the cell laminating step in which the distance between the adjacent cells is wide and before the pressurizing step. Since the connector can be assembled without receiving it and the connector is connected to the detection terminal at the same time as pressurization, the working time can be shortened.

Japanese Unexamined Patent Publication No. 2009-187677

However, in the technique described in Patent Document 1, a hole is provided in the central portion of the detection terminal, and the connector is provided with a convex connector terminal that fits with the hole of the detection terminal, so that the detection terminal and the connector can be connected to each other. At the connection stage (pressurization process), the hole of the detection terminal and the connector terminal are fitted and connected, but when the connector is deformed by pressurization in the pressurization process, local stress is applied. Could occur and break, resulting in a short circuit between adjacent cells.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress the generation of local stress of the connector when pressurized in the pressurizing step and the accompanying breakage of the connector. It is an object of the present invention to provide a method for assembling a cell monitor connector capable of suppressing a short circuit between cells.

In order to solve the above problems, the cell monitor connector assembling method according to the present invention is a cell monitor connector assembling method for monitoring the cell voltage of the fuel cell in the fuel cell stack, and the fuel cell is defined. After arranging a cell monitor connector having a recess formed on one side between the fuel cell cells in the fuel cell stack precursor in which a plurality of sheets are laminated at intervals, a load is applied to the fuel cell stack precursor in the stacking direction. It is characterized in that the fuel cell stack is formed by fastening the fuel cell cells with a narrow space between them.

According to the present invention, when a load is applied to the fuel cell stack precursor in the stacking direction (pressurization step), the deformation of the connector is absorbed by the recess formed on one side of the connector, so that the connector is locally localized. It is possible to suppress the generation of various stresses and the accompanying breakage of the connector, and to prevent short circuits between cells.

It is sectional drawing of the main part of a fuel cell stack. It is a flow chart which shows the outline of the manufacturing process of the fuel cell stack to which the assembling method of the cell monitor connector by this invention is applied. It is a flow chart which shows the outline of the manufacturing process of the fuel cell stack to which the conventional cell monitor connector assembling method is applied.

Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings. In the following, as an example, a case where the present invention is applied to a fuel cell mounted on a fuel cell vehicle or a fuel cell system including the present invention will be described as an example, but the scope of application is not limited to such an example. ..

[Fuel cell stack configuration]
First, with reference to FIG. 1, the configuration of a polymer electrolyte fuel cell as an example of a fuel cell stack (fuel cell) to which the method for assembling a cell monitor connector according to the present invention is applied will be outlined.

FIG. 1 is a cross-sectional view of a main part of the fuel cell stack (fuel cell) 10. As shown in FIG. 1, a plurality of cells (cells) 1 which are basic units are laminated on the fuel cell stack 10 (cell laminated body 9). Each cell 1 is a solid polymer fuel cell that generates an electromotive force by an electrochemical reaction between an oxidant gas (for example, air) and a fuel gas (for example, hydrogen). The cell 1 includes a MEGA 2 and a separator (fuel cell separator) 3 that contacts the MEGA 2 so as to partition the MEGA 2. In this embodiment, MEGA2 is sandwiched by a pair of separators 3 and 3.

MEGA2 is a combination of a membrane electrode assembly (MEA) 4 and gas diffusion layers 7 and 7 arranged on both sides thereof. The membrane electrode assembly 4 is composed of an electrolyte membrane 5 and a pair of electrodes 6 and 6 bonded so as to sandwich the electrolyte membrane 5. The electrolyte membrane 5 is made of a proton-conducting ion exchange membrane made of a solid polymer material, and the electrode 6 is made of, for example, a porous carbon material carrying a catalyst such as platinum. The electrode 6 arranged on one side of the electrolyte membrane 5 serves as an anode, and the electrode 6 on the other side serves as a cathode. The gas diffusion layer 7 is formed of a gas-permeable conductive member such as a carbon porous body such as carbon paper or carbon cloth, or a metal porous body such as a metal mesh or foamed metal.

In the present embodiment, the MEGA 2 is the power generation unit of the fuel cell 10, and the separator 3 is in contact with the gas diffusion layer 7 of the MEGA 2. When the gas diffusion layer 7 is omitted, the membrane electrode assembly 4 is the power generation unit, and in this case, the separator 3 is in contact with the membrane electrode assembly 4. Therefore, the power generation unit of the fuel cell 10 includes the membrane electrode assembly 4 and comes into contact with the separator 3.

The separator 3 is a plate-shaped member whose base material is a metal having excellent conductivity and gas impermeableness, and one side thereof is in contact with the gas diffusion layer 7 of MEGA2, and the other side is adjacent to another separator. It is in contact with the other surface side of 3.

In the present embodiment, each separator 3 is formed in a wavy or uneven shape. The shape of the separator 3 is such that the shape of the wave is an isosceles trapezoid, the top of the wave is flat, and both ends of the top are angular at equal angles. That is, each separator 3 has substantially the same shape when viewed from the front side and the back side. The top of the separator 3 is in surface contact with one gas diffusion layer 7 of MEGA2, and the top of the separator 3 is in surface contact with the other gas diffusion layer 7 of MEGA2.

The gas flow path 21 defined between the gas diffusion layer 7 on the one electrode (that is, the anode) 6 side and the separator 3 is a flow path through which the fuel gas flows, and the other electrode (that is, the cathode) 6 side. The gas flow path 22 defined between the gas diffusion layer 7 and the separator 3 is a flow path through which the oxidant gas flows. When the fuel gas is supplied to one of the gas flow paths 21 facing each other via the cell 1 and the oxidant gas is supplied to the gas flow path 22, an electrochemical reaction occurs in the cell 1 to generate an electromotive force.

Further, one cell 1 and another cell 1 adjacent thereto are arranged so that the electrode 6 serving as an anode and the electrode 6 serving as a cathode face each other. Further, a top of the back side of the separator 3 arranged along the electrode 6 which is the anode of a certain cell 1 and a top of the back side of the separator 3 arranged along the electrode 6 which is the cathode of another cell 1. Are in surface contact with each other. Water as a refrigerant for cooling the cell 1 flows through the space 23 defined between the separators 3 and 3 which are in surface contact with each other between the two adjacent cells 1.

The fuel cell stack 10 composed of the cell stack 9 formed by stacking a plurality of the cells 1 is housed in, for example, a stack case 11 (not shown in FIG. 1, see FIG. 2), and both ends of the stack (cells). Both ends of the cell stacking direction of the laminated body 9 are sandwiched between a pair of end plates (not shown), and a restraining member composed of a tension plate (not shown) is arranged so as to connect these end plates in the stacking direction. Is applied and fastened. The tension plate that restrains the cell laminate 9 and the like in a laminated state is provided so as to bridge the two end plates, and for example, a pair is arranged so as to face both sides of the fuel cell stack 10. .. The tension plate is connected to each end plate and maintains a state in which a predetermined fastening force (compressive load) is applied in the stacking direction of the cell laminate 9.

Further, in the present embodiment, the connector 15 (for example, a connector 15 (for example, fluctuation of the cell voltage during power generation) for measuring the voltage (cell voltage) of each cell 1 on the fuel cell stack 10 and monitoring the power generation state (for example, fluctuation of the cell voltage during power generation). In FIG. 1, not shown, see FIG. 2) are connected. The connector 15 is formed of, for example, an elastic material and has a recess 16 formed on one side thereof, and a detection terminal provided at an end of a separator 3 constituting the cell 1 (not shown in FIG. 1; FIG. 2). (See) is electrically connected (more on this later). The detection terminal of the separator 3 may be provided separately from the separator 3 (see, for example, Patent Document 1), or may be formed integrally with the separator 3.

[Configuration and assembly method of cell monitor connector in fuel cell stack]
Next, with reference to FIG. 2, the manufacturing process of the fuel cell stack, particularly the configuration of the cell monitor connector in the fuel cell stack and the assembling process thereof will be described.

FIG. 2 is a flow chart showing an outline of a manufacturing process of a fuel cell stack to which the method of assembling a cell monitor connector according to the present invention is applied.

As shown in FIG. 2, the manufacturing process of the fuel cell stack 10 mainly includes a cell stacking process (S1), a connector assembling process (S2), a pressurizing process (S3), and an insertion / fastening process (S4). Consists of including.

First, in the cell stacking step (S1), a plurality of the above-mentioned cells 1 are laminated at predetermined intervals (for example, at a pitch of about 2 mm) to form a fuel cell stack precursor (stacked body which is a base of the fuel cell stack 10) 8. do.

Next, in the connector assembling step (S2), between adjacent detection terminals 1a provided on the separator 3 of each cell 1 in the fuel cell stack precursor 8, on one side of the surfaces facing the detection terminals 1a. The connector 15 in which the recess 16 is formed is inserted and arranged. The connector 15 is formed of, for example, an elastic material, and has a width substantially the same as or slightly smaller than the width between adjacent detection terminals 1a (for example, about 2 mm). The number of recesses 16 provided in the connector 15 is not limited to the illustrated example, and may be one or a plurality. The number, shape, position, etc. of the recesses 16 provided in the connector 15 are determined in consideration of the amount of deformation of the connector 15 in the pressurizing step (S3) described later.

Next, in the pressurization step (S3), the fuel cell stack precursor 8 is pressurized (loaded) in the stacking direction (of cell 1) by using the end plate, tension plate, or the like, and each cell is pressed. The gas diffusion layers 7 and 7 of No. 1 are compressionally deformed to narrow the distance between the cells 1 (for example, from about 2 mm pitch to about 1 mm pitch). At this time, since the distance between the detection terminals 1a provided on the separator 3 of each cell 1 is also narrowed, the connectors 15 arranged between them are held by being pinched (compressed) and deformed by the adjacent detection terminals 1a. The connector 15 and the detection terminal 1a are electrically connected.

Then, in the insertion / fastening step (S4), the fuel cell stack precursor 8 that is pressed and held by the end plate, the tension plate, and the like and to which the connector 15 is assembled is inserted into the stack case 11. To conclude. As a result, the fuel cell stack 10 to which the cell voltage monitoring connector 15 is connected is manufactured.

As described above, in the present embodiment, the connector 15 is inserted between the adjacent detection terminals 1a after the cell laminating step (S1) in which the distance between the adjacent cells 1 is wide and before the pressurizing step (S3). By inserting and assembling, the work time for assembling the connector can be shortened, and erroneous assembly can be prevented.

Further, in the present embodiment, when a load is applied to the fuel cell stack precursor 8 in the stacking direction (of cell 1) (pressurization step (S3)), deformation of the connector 15 is formed on one side of the connector 15. Since it is absorbed by the recess 16, it is possible to suppress the generation of local stress in the connector 15 and the accompanying breakage of the connector 15, and it is possible to suppress a short circuit between the cells 1.

Further, in the present embodiment, as compared with the case where recesses are formed on both sides of the connector 15 (both sides facing the adjacent detection terminals 1a), one side (recesses 16 are not formed) during compression in the pressurizing step (S3). Since the side) side is always left, the possibility of disconnection of the connector 15 is reduced, and there is an advantage that a short circuit between the cells 1 can be reliably prevented.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like within a range that does not deviate from the gist of the present invention. Also, they are included in the present invention.

1 ... cell (fuel cell), 1a ... cell detection terminal, 2 ... MEGA, 3 ... separator, 4 ... membrane electrode assembly (MEA), 5 ... electrolyte membrane, 6 ... electrode, 7 ... gas diffusion layer, 8 ... Fuel cell stack precursor, 9 ... Cell laminate, 10 ... Fuel cell stack (fuel cell), 11 ... Stack case, 15 ... Connector (cell monitor connector), 16 ... Connector recess, 21, 22 ... Gas flow path , 23 ... Space where water flows

Claims (1)

A method of assembling a cell monitor connector for monitoring the cell voltage of a fuel cell in a fuel cell stack.
A cell monitor connector in which a recess in a stacking direction depth less than the thickness of the cell monitor connector is formed between the fuel cell cells in a fuel cell stack precursor in which a plurality of fuel cell cells are stacked at predetermined intervals. After placing
A method of assembling a cell monitor connector, wherein a load is applied to the fuel cell stack precursor in the stacking direction, and the fuel cell stacks are fastened with a narrow space between the fuel cell cells to form the fuel cell stack.

Images