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A cell-voltage measuring structure for a fuel cell stack, in which a plurality of unit cells, having conductive separators which includes anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each

A cell-voltage measuring structure for a fuel cell stack, in which a plurality of unit cells, having conductive separators which includes anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each other, respectively, are stacked in a stack direction, is provided with a voltage-measuring unit having a conductive voltage-measuring terminal, a contact section, with which the conductive voltage-measuring terminal is to be held in contact, formed on an outer periphery of a first pair of unit separators, a non-contact section, with which the conductive voltage-measuring terminal is not to be held in contact, formed on an outer periphery of a second pair of unit separators adjacent to the first pair of unit separators. A length of the conductive voltage-measuring terminal is greater than a thickness of the first pair of unit separators, in the stack direction.

대표청구항 ▼

What is claimed is: 1. A cell-voltage measuring structure for a fuel cell stack in which a plurality of unit cells, having conductive separators, are stacked in a stack direction, the conductive separators including anode-side separators and cathode-side separators to form pairs of unit separators

What is claimed is: 1. A cell-voltage measuring structure for a fuel cell stack in which a plurality of unit cells, having conductive separators, are stacked in a stack direction, the conductive separators including anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each other, respectively, the structure comprising: a voltage-measuring unit having a conductive voltage-measuring terminal; a contact section, with which the conductive voltage-measuring terminal is to be held in face to face contact, formed on a side face, which is defined by the stack direction and a direction perpendicular to the stack direction, of a first pair of unit separators; and a non-contact section, with which the conductive voltage-measuring terminal is to not be held in contact, concavely formed on a side face, which is defined by the stack direction and a direction perpendicular to the stack direction, of a second pair of unit separators adjacent to the first pair of unit separators, a length of the conductive voltage-measuring terminal in the stack direction being greater than a thickness of the first pair of unit separators in the stack direction, and the conductive voltage-measuring terminal extending in the stack direction to contact the contact section without contacting the non-contact section which is adjacent to the contact section. 2. The cell-voltage measuring structure according to claim 1, wherein the voltage-measuring unit is to be brought into abutting contact with a surface of the fuel cell stack on one side thereof on which the contact section and non-contact section are formed. 3. The cell-voltage measuring structure according to claim 1, wherein the non-contact section includes a relative concave portion formed on the side face of the second pair of unit separators. 4. The cell-voltage measuring structure according to claim 1, wherein the contact section includes a relative convex portion formed on the side face of the first pair of unit separators. 5. The cell-voltage measuring structure according to claim 1, wherein the fuel cell stack includes a third pair of unit separators formed with the contact section in position to overlap, in the stack direction, with that of the first pair of unit separators, and further includes an intermediate pair of unit separators, disposed between the first pair of unit separators and the third pair of unit separators, which are formed with the non-contact section in position to overlap, in the stack direction, with the contact section of the first pair of unit separators and that of the third pair of unit separators. 6. The cell-voltage measuring structure according to claim 5, wherein depending on the number of the intermediate pair of unit separators, the non-contact section is disposed on the intermediate pair of unit separators, respectively. 7. The cell-voltage measuring structure according to claim 5, wherein a length of the conductive voltage-measuring terminal in the stack direction is determined depending on the number of the intermediate pair of unit separators. 8. The cell-voltage measuring structure according to claim 1, wherein a contact section of one pair of unit separators is dislocated from that of the other pair of unit separators, adjacent thereto, so as to not overlap with one another in the stack direction. 9. The cell-voltage measuring structure according to claim 1, wherein the voltage-measuring unit includes the conductive voltage-measuring terminal, which is made of resilient material, and a nonconductive plate and operative such that when the voltage-measuring unit is brought into abutting contact with a surface of the fuel cell stack on one side thereof on which the contact section and the non-contact section are formed, the conductive voltage-measuring terminal is brought into abutting contact with the contact section under a resiliently deformed condition. 10. The cell voltage measuring structure according to claim 1, wherein the voltage-measuring unit includes a nonconductive resilient plate, on which the conductive voltage-measuring terminal is placed, and the conductive voltage-measuring terminal is bonded to the contact section. 11. The cell-voltage measuring structure according to claim 1, wherein the voltage-measuring unit includes a set of measuring unit split bodies, which are divided into two pieces in the stack direction, one of which is positioned at and fixedly secured to one end of the fuel cell stack in the stack direction and the other end of which is positioned at and fixedly secured to the other end of the fuel cell stack in the stack direction. 12. The cell-voltage measuring structure according to claim 1, wherein the plurality of unit cells are stacked in a way wherein ends of the plurality of unit cells are held in contact with the conductive voltage-measuring terminal and are aligned with respect to one another. 13. The cell-voltage measuring structure according to claim 1, wherein a number of non-contact sections of each pair of unit separators is determined based on a value obtained by multiplying a dimensional tolerance of a cell pitch in the stack direction by a number of stacks of the plurality of unit cells and dividing the resultant value by the cell pitch. 14. The cell-voltage measuring structure according to claim 1, wherein a number of non-contact sections in each of the plurality of unit cells is equal to or less than 7 pieces. 15. A cell-voltage measuring structure for a fuel cell stack in which a plurality of unit cells, having conductive separators, are stacked in a stack direction, the conductive separators including anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each other, the structure comprising: a voltage-measuring unit having a conductive voltage-measuring terminal; first means for face to face contacting the conductive voltage-measuring terminal, the first means being formed on a side face, which is defined by the stack direction and a direction perpendicular to the stack direction, of a first pair of unit separators; and second means for avoiding contact with the conductive voltage-measuring terminal, the second means being concavely formed on a side face, which is defined by the stack direction and a direction perpendicular to the stack direction, of a second pair of unit separators adjacent to the first pair of unit separators, a length of the conductive voltage-measuring terminal in the stack direction being greater than a thickness of the first pair of unit separators in the stack direction, and the conductive voltage-measuring terminal extending in the stack direction to contact the first means without contacting the second means which is adjacent to the first means. 16. A cell-voltage measuring method of measuring a cell-voltage of a fuel cell stack in which a plurality of unit cells, having conductive separators, are stacked in a stack direction, the conductive separators including anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each other, comprising: providing a voltage-measuring unit having a first conductive voltage-measuring terminal and a second conductive voltage-measuring terminal; providing a fuel cell stack including a first pair of unit separators and a second pair of unit separators, a first contact section being formed on a side face, which is defined by the stack direction and a direction perpendicular to the stack direction, of the first pair of unit separators to be held in contact with the first conductive voltage-measuring terminal, a first non-contact section being concavely formed on the side face of the first pair of unit separators to not be held in contact with the second conductive voltage-measuring terminal, a second contact section being formed on a side face, which is defined by the stack direction and a direction perpendicular to the stack direction, of the second pair of unit separators to be held in face to face contact with the second conductive voltage-measuring terminal, a second non-contact section being concavely formed on the side face of the second pair of unit separators to not be held in contact with the first conductive voltage-measuring terminal, a length of the first conductive voltage-measuring terminal in the stack direction being greater than a thickness of the first pair of unit separators in the stack direction and the first conductive voltage-measuring extending in the stack direction to contact the first contact section without contacting the first non-contact section which is adjacent to the first contact section, and a length of the second conductive voltage-measuring terminal in the stack direction being greater than a thickness of the second pair of unit separators in the stack direction and the second conductive voltage-measuring terminal extending in the stack direction to contact the second contact section without contacting the second non-contact section which is adjacent to the second contact section; and measuring a cell-voltage of the fuel cell stack while causing the first contact section to contact the first conductive voltage-measuring terminal and the second contact section to contact the second conductive voltage-measuring terminal.