JPS5893173A - Fuel cell stack clamping apparatus - Google Patents

Abstract

PURPOSE:To clamp a fuel cell at constant pressure in spite of decrease of stacking height with the passage of time, and detect from outside the decrease of stacking height of a fuel cell by setting metal bellows in the circumference of a fuel cell stack accommodating and clamping container. CONSTITUTION:The upper and lower surfaces of a fuel cell stack 11 are interposed between end plates 12, and preclamped with a clamping rod 16 between heat insulating clamping plates 13. The preclamped stack is placed on a clamping container bottom plate 14, and covered with a clamping container 17 having expansion metal bellows 21 in its circumference so that a compressing plate 15 enters the concavity of the clamping plate 13. The pressure is applied to the stack 11 with the compressing plate 15 via an actuator 19, a pressure transfer rod 18, and the clamping container 17 from a pressure supply source 20. Height decrease of the stack is detected with a dial gauge 22 installed in the outside of the clamping container.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a tightening structure for a fuel cell stack formed by stacking single fuel cells.

Technical Background of the Invention Conventionally, a fuel cell stack is produced by stacking single fuel cells and tightening the stack with a constant torque from above and below using clamping plates provided above and below the stack, and nine clamping rods installed around the clamping plates. After that, it was stored in a pressure vessel.

A conventional example is shown in Figure 1. After the fuel cell stack 1 is tightened from above and below by the end plate 2 and the clamping plate 3 by the clamping rod 5 around the clamping plate 3, the stack 1 is tightened in the pressure vessel 4. Store it in.

Problems with the Background Art With the conventional tightening structure, the torque at each tightening rod tends to fluctuate when tightening the fuel cell stack, and the stack deteriorates over time when used in a high-temperature atmosphere after the battery is activated. Due to deterioration of the tightening bolts, etc., the bolts may become loose. This loosening of the tightening leads to a decrease in performance due to an increase in the electrical resistance of the fuel cell stack, making it necessary to re-tighten it periodically. To retighten the pressure vessel, it is necessary to expand the pressure vessel and tighten it manually. It was difficult to detect loosening of the clamping pressure of the nine fuel cell stacks housed in nine pressure vessels. Therefore, there is a need for a structure in which the fuel cell stack is always tightened at a constant pressure while the cell is in operation, and any loosening of the tightening due to a decrease in the height of the fuel cell stack can be detected from outside the pressure vessel.

Purpose of the Invention The present invention has been made to improve the drawbacks of such a tightening structure, and is to provide a stretchable metal bellows around the pressure vessel housing the fuel cell stack. The pressure plate of the fuel cell stack and the external pressure mechanism are integrated, and the fuel cell is always tightened at a constant pressure regardless of the decrease in stack height of the fuel cell over time. An object of the present invention is to provide a fuel cell stack clamping structure that can detect a decrease in height.

Effects of the Invention According to the present invention, it is possible to tighten with a constant pressure while constantly detecting the height displacement of the laminate from the outside, and there is no need to interrupt operation, open the container, and periodically retighten. , operational efficiency can be improved.

Examples of the invention DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the configuration of the present invention will be illustrated below with reference to the drawings.

An embodiment of the present invention is shown in FIG. 2, a fuel cell stack 11.
The upper and lower surfaces are sandwiched between the end plates 12 and then temporarily tightened using the tightening rod 16 using the heat insulating tightening base 13. After the temporary tightening, the carcass is placed on the bottom mount of the pressure vessel. 14, and a pressure vessel 17 having an elastic metal bellows 21 around it is covered so that the pressure plate 15 enters the recess of the clamping plate 13. Pressure is applied to the stacked body 11 from a pressure supply source through an actuator 19, a pressure transmission rod 18, and a pressure vessel 17 [15 to n].

According to the present invention 8), during battery operation, a constant pressure is applied to the fuel cell stack regardless of deterioration of the stack, loosening of tightening bolts, etc., and the pressure vessel is removed. As a result, it was possible to omit the work required to correct loose tightening and maintain performance in continuous operation tests.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a conventional example, and FIG. 2 is a vertical sectional view showing an embodiment according to the present invention. DESCRIPTION OF SYMBOLS 11... Fuel cell stack 12... End plate 13... Tightening plate 14... Pressure vessel bottom frame 15-knee pressure plate 16... Tightening rod 17... Pressure vessel 18... Pressure Transmission rod 19...actuator application...pressure supply source 2
1...Metallic bellows n...Dial gauge Patent attorney Noriyuki Chika (and 1 other person) Figure 1

Claims (1)

[Claims] A pressure vessel having a stretchable metal bellows around a round vessel for storing a fuel cell stack, a round pressurizing mechanism for pressurizing a pressure volume 1f) from the outside of the pressure vessel, and an inner wall of the pressure vessel. 9 pressurizing plates directly connected to the pressurizing mechanism to pressurize the fuel cell stack, a round tightening rod to be tightened when assembling the fuel cell stack, and 9 fuel plates attached to the outer wall of the pressure vessel. A tightening structure for a fuel cell stack, including a measuring mechanism for measuring a reduction in height of the battery stack.