JPH09161828A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly distribute and supply an anode gas to the respective cells of a battery stack, without complicating structure to promote power generation efficiency, by improving the structure of an outside manifold. SOLUTION: In a fuel cell wherein an external manifold 40 is mounted on the surface in which the anode gas inflow side end part opening of the anode gas channel 34 of a battery stack 30, the following constitution is adopted to the external manifold 40. That is, a partitioning plate 51 is installed in a direction crossing an anode gas flowing direction in an anode gas flowing space 43, between the inner wall of the external manifold 40 and the surface of the battery stack 30, and an anode gas flowing space 43 is partitioned into a first space on a battery stack surface 37 side, and a second space including an anode gas inlet part 44, for supplying an anode gas to the external manifold 40, by the partitioning plate 51. One or two or more through holes 54 are opendly mounted on main surface of the partitioning plate 51, and an anode gas passes the through hole(s) to flow from a space 2 to a space 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell,
In particular, it relates to a fuel cell using an external manifold.

[0002]

2. Description of the Related Art A fuel cell is assembled by alternately stacking a predetermined number of cells, each having a cell in which an anode and a cathode are arranged through an electrolyte layer, and a separator plate having an anode gas channel and a cathode gas channel formed on both surfaces thereof. The anode gas (hydrogen-rich fuel gas) and the cathode gas (oxidant gas such as air) are supplied to the battery stack, respectively. When the anode gas and the cathode gas undergo an electrochemical reaction, By extracting chemical energy as electric energy, electric power is supplied to the outside. Above all, a fuel cell provided with a small cell stack in which small-sized cells are stacked is excellent in portability, and is attracting attention as a power source for civil engineering work outdoors and an emergency power source indoors.

The battery stack is provided with an anode gas distribution manifold and an anode gas recovery manifold for distributing the anode gas to the anode gas channel and collecting the anode gas from the anode gas channel. Such manifolds are classified into a lid-shaped external manifold that covers the surface where the end opening of the anode gas channel of the battery stack is exposed, and an internal manifold in which through holes and grooves are formed inside the battery stack. . Since the external manifold has a simpler structure than the internal manifold and can be attached to a small cell stack with good workability, it is often used in a small fuel cell.

By the way, the anode manifold is provided with an anode gas inlet portion in the external manifold for distributing the anode gas, and the anode gas pipe is connected thereto. However, in order to make the fuel cell as compact as possible, this anode gas inlet portion is usually used. Part is provided on the side surface of the outer peripheral part of the external manifold,
The structure is such that the anode gas pipe does not extend outside the main surface of the external manifold.

[0005]

However, in a fuel cell using such an external manifold, most of the anode gas taken into the external manifold is supplied to cells located in the vicinity of the anode gas inlet. However, the cells are not supplied so much to the cells located far from the anode gas inlet, so that the distribution and supply of the anode gas to the cells in the battery stack are uneven.

In a cell with a small amount of supplied anode gas, that is, a cell located far from the anode gas inlet, a predetermined power generation voltage cannot be obtained, and as a result, high power generation efficiency cannot be obtained. was there. Such a problem has been particularly remarkable when the flow rate of the anode gas is low, that is, when the fuel cell is operated under a low load or when the utilization rate of the anode gas is high.

To solve such a problem, for example, the position of the anode gas inlet of the anode gas distribution manifold is provided on the upper surface of the anode gas distribution manifold, or the anode gas flows into the anode gas distribution space of the anode gas distribution manifold. It is possible to distribute and supply the anode gas to each cell of the battery stack to a certain extent by inserting a branch pipe for the anode gas and devising the blowing direction of the anode gas in the anode gas distribution manifold. Although it is thought that the above problems can be solved, in such a case, the anode gas distribution manifold becomes bulky, and the shape of the anode gas piping from the anode gas inlet becomes complicated. Therefore, it takes time and effort to manufacture, and the manufacturing cost increases.

Particularly in a small-sized fuel cell, since the gas distribution space in the external manifold is also narrow, it is not easy to provide the branch pipe as described above in the external manifold, and this is not a preferable method. Therefore, in view of the above problems, the present invention does not move the position of the anode gas inlet of the external manifold in a fuel cell using the external manifold for anode gas distribution, and complicates the structure around the external manifold. It is an object of the present invention to provide a fuel cell capable of uniformly distributing and supplying an anode gas to each cell of a cell stack.

[0009]

In order to solve the above problems, in the invention according to claim 1, a cell in which an anode and a cathode are arranged via an electrolyte layer, and an anode gas channel and a cathode gas channel are provided on both sides. In a fuel cell in which an external manifold is attached to the surface where the anode gas inflow side end opening of the anode gas channel of a battery stack in which a plurality of separator plates formed alternately are laminated, the external manifold is
A partition plate is installed in the anode gas flow space between the inner wall of the external manifold and the battery stack surface in a direction intersecting with the anode gas flow direction, and the anode gas flow space is provided by the partition plate to the battery stack surface side. Is divided into a first space and a second space including an anode gas inlet portion for supplying an anode gas to the external manifold, and the main surface of the partition plate has one or more penetrating holes. A hole is opened, and the anode gas is configured to flow from the second space to the first space through the through hole.

In this fuel cell, the anode gas taken in from the anode gas inlet is discharged into the first space through one or more through holes through the second space. The released anode gas is
It spreads while advancing in the space toward the battery stack and enters into each anode gas channel of the battery stack.

Here, if the position of the through hole or the distance between the partition plate and the cell stack is appropriately set, the anode gas can be uniformly dispersed in the entire anode gas channel. In the above, the appropriate setting can be easily performed only by adjusting the opening position of the through hole in the partition plate and the mounting position of the partition plate in the anode gas distribution manifold.

Further, since it is only necessary to provide the partition plate in the space of the anode gas distribution manifold similar to the conventional one, the structure of the fuel cell is simple and its fabrication is relatively easy. Further, in the invention according to claim 2, the partition plate is characterized in that two or more through-holes are dispersedly formed so as to be substantially uniform over the entire main surface of the partition plate. There is.

Therefore, according to the second aspect of the invention, since the anode gas is introduced into the first space through the two or more uniformly distributed through holes, the anode gas for each cell is Uniform distribution can be achieved more effectively. In the invention according to claim 3, in the installation position of the partition plate in the anode gas flow space of the external manifold, the ratio V / Q of the volume V of the battery stack to the volume Q of the first space is 15 It is characterized in that it is selected at a position that defines the volume Q of the first space so as to be 40 or more.

The present researchers have so far developed a ratio V / V of the volume V of the battery stack and the volume Q of the first space of the external manifold.
As a result of producing a fuel cell in which Q is variously changed and measuring the generated voltage of each cell for each fuel cell, the volume V of the cell stack is the volume Q of the first space of the external manifold.
15 times or more and 40 times or less,
It has been found that the power generation efficiency of the fuel cell is improved by mounting the partition plate in the anode gas distribution manifold so that the V / Q value falls within such a range.

Therefore, according to the third aspect of the invention, the fuel cell is constructed so that the ratio V / Q of the volume V of the cell stack and the volume Q of the first space of the external manifold is 15 or more and 40 or less. Therefore, the supply of the anode gas to each cell can be made uniform, and the power generation characteristics of the fuel cell can be improved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is an overall perspective view of a portable fuel cell system equipped with a fuel cell according to the present invention. For convenience of explanation, the left direction of the drawing is the left direction of the portable fuel cell system, and the upper direction of the drawing is the upper direction of the portable fuel cell system.

In the portable fuel cell system, as shown in FIG. 1, the hydrogen storage alloy tank 2 is housed in the left side space 101 of the housing 1, and the fuel cell 3 is housed in the central space 103.
The air supply fan 4 and the control device 5 in the upper space 104,
Each of the catalytic combustors 6 is installed in the right side space 102. In addition, a slit-shaped air intake 13 is opened in the upper part of the casing 1, and an air discharge port 14 is opened in the closing lid 15. However, the casing 1 can be covered with an upper lid 16, and a portable fuel can be used. When the battery system is not used, air is prevented from entering the housing 1 through the air intake port 13 and the air exhaust port 14.

The hydrogen storage alloy tank 2 comprises a pair of columns 2
Between the 1 and 21, for example, five hydrogen storage alloy tank single bodies 22, ... Are laid horizontally, and a hydrogen delivery coupler 23, which serves as a hydrogen gas delivery port, is provided at the upper end of one of the columns 21.
Is provided. The hydrogen delivery coupler 23 and a hydrogen inlet 44 (see FIG. 2) of the fuel cell 3 described later are connected by a hydrogen supply pipe 24, and hydrogen gas is fed into the fuel cell 3.

The air supply fan 4 serves to take in air from the air intake 13 into the housing 1 and supply it to the fuel cell 3. The control device 5 controls various controls related to the operation of the portable fuel cell system, such as the control of the flow rate of hydrogen gas supplied to the fuel cell 3 and the control of the air flow rate of the air supply fan 4.

The catalytic combustor 6 has a function of catalytically burning unreacted hydrogen that has not been subjected to an electrochemical reaction by the hydrogen gas fed into the fuel cell 3. FIG. 2 is an exploded perspective view of the fuel cell 3, and FIG. 3 is a partially enlarged view of a section taken along line XX of FIG. The fuel cell 3, as shown in FIG.
The hydrogen distribution manifold 4 is provided on the upper surface 37 of the battery stack 30.
0 is arranged, and the hydrogen recovery manifold 41 is arranged on the lower surface (not shown) for assembly.

The cell stack 30 includes an anode (not shown) on one side of an electrolyte matrix impregnated with phosphoric acid.
With a cathode and a cathode (not shown) on the other side
1, and a plurality of air channels 33, ...
A predetermined number (for example, 30 cells 31) of separator plates 32 each having a plurality of hydrogen channels 34 formed in the vertical direction are alternately stacked in the front-rear direction, and both ends thereof are formed by a pair of end plates 35, 35. It is configured to hold down, the end openings of the air channels 33, ... Are exposed on the left side surface 36 and the right side surface (not shown) of the battery stack 30, and the upper surface 37 and the lower surface (not shown) of the battery stack 30 are exposed. )
, The end openings of the hydrogen channels 34, ... Are exposed.

The hydrogen distribution manifold 40 is made of a heat-resistant material such as urea resin or melamine resin, and serves as a hydrogen gas distribution space in the center of the lower surface of a plate-like member having the same vertical and horizontal dimensions as the upper surface 37 of the battery stack 30. It has a configuration in which a recess 43 is provided. Then, in the recess 43, the recess 4
A partition plate 51 is attached in parallel with the bottom surface 40a of No. 3. In this embodiment, the hydrogen distribution manifold 40 has outer dimensions of 130 mm in length × 120 mm in width × 20 mm in height.

On the left side surface of the outer peripheral portion 42 of the recess 43, there is provided a hydrogen inlet 44 which horizontally penetrates the outer peripheral portion 42 and communicates with the recess 43. The hydrogen delivery coupler 23 of the hydrogen storage alloy tank 2 is connected with the hydrogen supply pipe 24 (see FIG. 1) so that the hydrogen gas is introduced into the recess 43. The partition plate 51 is made of a heat-resistant material similar to that of the hydrogen distribution manifold 40, and has a recess 52 formed in the center of the upper surface of a plate body having the same vertical and horizontal outer dimensions as the vertical and horizontal inner dimensions of the recess 43.
The bottom surface 51a of the recess 52 has four through holes 5
4 are distributed and opened on a line that crosses the partition plate 51 in a diagonal direction. In this embodiment, the height H (see FIG. 3) of the partition plate 51 is 5 mm and the diameter of the through hole 54 is about 3 mm.

Further, in order to hold the partition plate 51 in the recess 43 at a position corresponding to the hydrogen inlet port 44 of the hydrogen distribution manifold 40 on the left side portion of the thick outer bank portion 56 surrounding the recess 52. The support piece 55 is fitted. The height of the support piece 55 is the depth I of the recess 43 (see FIG.
(See) is set to the same. Therefore, when the hydrogen distribution manifold 40 is assembled to the battery stack 30, the lower end of the support piece 55 is located on the upper surface 37 of the battery stack 30.
The partition plate 51 is supported by the support piece 55 so that the upper surface of the outer peripheral bank portion 56 and the bottom surface 40a of the recess 43 of the hydrogen distribution manifold 40 are in contact with each other. In addition, the upper end surface of the support piece 55 and the partition plate 5
A cutout 53 is formed in the outer peripheral bank portion 56 of No. 1 so that hydrogen gas can flow into the recess 52 from the hydrogen inlet 44.

Incidentally, the support piece 55 is formed of the hydrogen inlet 44.
The lower part of the opening on the side surface 45 side of the recess 43 is covered so that hydrogen gas does not directly flow into the battery stack 30 from the hydrogen inlet 44. On the other hand, the hydrogen recovery manifold 41 is made of the same size and the same material as the hydrogen distribution manifold 40, but the partition plate 51 is attached inside the recess (not shown) of the hydrogen recovery manifold 41. Absent. Further, a hydrogen discharge port (not shown) is opened at one end of the hydrogen recovery manifold 41,
By connecting a hydrogen exhaust pipe (not shown) to this hydrogen exhaust port and connecting the hydrogen recovery manifold 41 and the catalytic combustor 6, unreacted hydrogen is introduced into the catalytic combustor 6. There is.

In the fuel cell 3 having the above structure, the hydrogen gas distribution space in the hydrogen distribution manifold 40 is divided into two spaces 61 and 62 as shown in FIG.
That is, the bottom surface 40 of the recess 43 of the hydrogen distribution manifold 40.
a and the bottom surface 51a and the side surface 51 of the recess 52 of the partition plate 51
The second space 61 surrounded by b, the side surface 45 of the recess 43 of the hydrogen distribution manifold 40 and the lower surface 58 of the partition plate 51.
And a first space 62 surrounded by the upper surface 37 of the battery stack 30.
It is. The hydrogen gas in the second space 61 passes through the through holes 54, ...
Introduced in 2.

In the first space 62, the hydrogen gas flows downward while spreading in the horizontal direction, as shown by the black arrow P, and is introduced into the respective hydrogen channels 34, .... Therefore, by appropriately setting the opening positions of the through holes 54, ... In the partition plate 51 and the height T of the first space 62, the hydrogen gas can be dispersed almost uniformly over the entire upper surface 37 of the battery stack 30. .

The value of the height T of the first space 62 can be adjusted by changing the thickness H of the partition plate 51 without changing the depth I of the recess 43 of the hydrogen distribution manifold 40. . Further, the number of through-holes 54 and the opening positions can be easily adjusted when the partition plate 51 is manufactured, so that the adjustment for uniformly dispersing the hydrogen gas is easy.

In this embodiment, the four through holes 5
4, are opened at positions where the diagonal line of the partition plate 51 is divided into four (see FIG. 4A), but when the number of the through holes 54 is four, they are opened at such positions. Is desirable. As shown in FIG. 3, the height T of the first space 62 is such that the flow of hydrogen gas released from the respective through holes 54, ... Spreads sufficiently below the first space 62, and
The flows do not overlap each other, and the side surface 45 of the recess 43 is
It is considered that it is desirable to set the value so as not to collide with the above in order to achieve uniform dispersion of hydrogen gas.

In order to obtain better battery characteristics, the ratio V / Q of the volume V of the battery stack 30 and the volume Q of the first space 62 of the hydrogen distribution manifold 40 should be set in the range of 15 to 40. Although it is experimentally known that it is preferable to set the hydrogen distribution manifold 40 according to the present invention, as described above, the thickness H of the partition plate 51 is simply changed while the hydrogen distribution manifold 40 remains unchanged. The depth T of the first space 62 can be changed, and the volume Q of the first space 62 can be changed accordingly.

Therefore, even when the volume V of the battery stack 30 changes, the ratio V / Q of the volume V of the battery stack 30 and the volume Q of the first space 62 of the hydrogen distribution manifold 40 can be improved to improve the battery characteristics. It can be easily adjusted to an effective range (15 or more and 40 or less). In order to confirm the effect of the present invention, the conventional fuel cell (No. 1) in which the partition plate is not mounted in the recess 43 of the hydrogen distribution manifold 40, and the partition plate 51 in the recess 43 of the hydrogen distribution manifold 40, Partition plate 71, partition plate 81
Of the fuel cell of the present invention (No. 4 to
No. 2) was prepared and the generated voltage of each cell 31, ... Was measured.

The battery stack 30 used in the experiment was a stack of 30 cells 31 (cell area 190 cm ² ), the battery operating temperature was set to 100 ° C., and pure hydrogen gas was used as the anode gas to fuel the fuel. The utilization rate was 90% and the rated current value was 19A. Furthermore, the partition plate 5 used in the experiment
1. The partition plate 71 and the partition plate 81 are all the same size, but the number of through holes and the opening positions for the partition plate are different, and have the following shapes. That is, the partition plate 51, as shown in FIG.
Through-holes 54 each having a diameter of about 3 mm are provided at the midpoints of the line segments connecting the diagonal intersections G1 and the end points G2. Further, as shown in FIG. 4B, the partition plate 71 has through holes 72 each having a diameter of about 3 mm near the intersection G1 at a position where the line segment connecting the intersection G1 of the diagonal line and the end point G2 is divided into six equal parts. It has been opened. Further, as shown in FIG. 4C, the partition plate 81 has a through hole 82 having a diameter of about 6 mm at the intersection of the diagonal lines.
Has been established.

[0033]

[Table 1] The results are shown in Table 1, and the lowest value in Table 1 shows the lowest value at each power generation voltage of the 30 cells 31, .... As a result, the following can be seen. 100% load
When the load is 50% or the load is 50%, the fuel cell No. 2-No. 4 is a conventional fuel cell N
o. Compared with 1, the difference between the average value and the minimum value of the generated voltage is smaller. This is the fuel cell No. 1 of the present invention. 2
-No. 4 shows that the hydrogen gas is uniformly distributed to the cells 31, ....

Further, the fuel cell Nos. 2-N
o. No. 4 is the fuel cell No. of the conventional example. Compared with 1, the average value of the generated voltage itself has increased. This result also shows that the fuel cell No. 2-No. 4, each cell 31, ...
This proves that the hydrogen gas is evenly distributed to the air. In addition, the fuel cell No. of the conventional example. 1, load 1
Since the difference between the average value and the minimum value of the generated voltage at the time of 50% load is larger than that at the time of 00%, it can be seen that the distribution of hydrogen gas tends to become particularly uneven at low load. ． 2-No. In No. 4, when the load is 50%, the lowest value of the generated voltage is the fuel cell No. of the conventional example. 1
In comparison with the above, it is also increased by 40 to 50 mV, which shows that there is a great effect on the uniform distribution of hydrogen gas under a low load.

Further, each fuel cell No. Two
No. Comparing No. 4 with the fuel cell No. In No. 4, the average value of the generated voltage of the cells 31, ... Is the maximum, and the difference between the average value and the minimum value is the minimum, which is most effective for the uniform distribution of hydrogen gas. Fuel cell No. 2 is the second most effective in the uniform distribution of hydrogen gas. 3 and
The third is the fuel cell No. It was 2. From this, it is better that the number of through holes to be opened in the partition plate is more than one, and it is more effective that the opening positions are spread over the entire partition plate because of the uniform distribution of hydrogen gas. Recognize.

In this embodiment, the partition plate 5
The number of the through holes 54 formed in 1, ... Is set to one or four, but the number is not limited to this, and the size of the partition plate 51, the size of the battery stack 30, the flow rate of hydrogen gas, its momentum, etc. Based on the above, it may be set so as to obtain the optimum effect. In addition, the concave portion 4 of the hydrogen distribution manifold 40
When attaching the partition plate 51 to the inside of the
It is also possible to pack between 0a and the outer peripheral bank portion 56 of the partition plate 51 using a material having excellent heat resistance and chemical resistance, such as fluororubber.

Further, the partition plate may be formed of a flat thin plate having a plurality of through holes, and the edge portion and the side surface 45 of the recess 43 of the hydrogen distribution manifold 40 may be fixed to each other by, for example, welding. Since the partition plate can be held in the recess 43 and the hydrogen gas distribution space in the hydrogen distribution manifold 40 can be divided into the first space and the second space, the same effect can be obtained in that case as well. .

Further, in this embodiment, the phosphoric acid fuel cell is used, but the present invention is not limited to this. For example, a polymer electrolyte fuel cell may be used, or a small-sized portable power source. Not only the fuel cell but also any external manifold type fuel cell can be generally applied.

[0039]

As described above, according to the first aspect of the present invention, the anode gas distribution manifold itself can be designed without any change, and the anode gas distribution manifold can be simply attached with the partition plate. Distribution can be made uniform. Moreover, since the partition plate can be manufactured relatively easily and the configuration is simple, even a small fuel cell can be manufactured easily. And by making the distribution of the anode gas uniform,
The power generation characteristics of the fuel cell can be improved.
Further, since it is possible to suppress variations in the generated voltage of each cell in the battery stack, it is possible to prevent some cells from deteriorating earlier than other cells, and improve the life characteristics of the fuel cell. It is also connected, and the economic effect is great. Furthermore, it is also possible to use one shape of the external manifold together with a plurality of battery stacks.

Furthermore, according to the invention of claim 2, two or more through holes are uniformly distributed and opened in the partition plate. Therefore, the anode gas is more uniformly distributed and supplied to each cell, so that the power generation characteristics of the fuel cell can be improved more effectively. Further, according to the invention described in claim 3, the power generation characteristics of the fuel cell can be further improved.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a portable fuel cell system according to the present invention.

FIG. 2 is an exploded perspective view of a fuel cell according to the present invention.

FIG. 3 is a partially enlarged view of a section taken along line XX of FIG.

4A is a perspective view of a partition plate 51. FIG. (B) It is a perspective view of the partition plate 71. (C) It is a perspective view of the partition plate 81.

[Explanation of symbols]

 3 Fuel Cell 30 Cell Stack 31 Cell 32 Separator Plate 33 Air Channel 34 Hydrogen Channel 40 Hydrogen Distribution Manifold 41 Hydrogen Recovery Manifold 44 Hydrogen Inlet 51 Partition Plate 54 Through Hole 61 Second Space 62 First Space

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoshitoshi Ikenaga 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Kunihiro Nakato 2 Keihanhondori, Moriguchi-shi, Osaka 5-5-5 Sanyo Electric Co., Ltd. (72) Inventor Nobuyoshi Nishizawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. An anode gas of a battery stack in which a plurality of cells in which an anode and a cathode are arranged via an electrolyte layer and a separator plate having an anode gas channel and a cathode gas channel formed on both surfaces thereof are alternately laminated. In a fuel cell in which an external manifold is capped on a surface of an end opening of an anode gas inflow side of a channel, the external manifold includes an anode gas distribution space between an inner wall of the external manifold and a cell stack surface. A partition plate is installed in a direction intersecting with the gas flow direction, and the anode gas flow space is defined by the partition plate to define a first space on the surface side of the battery stack and an anode gas inlet part for supplying anode gas to the external manifold. It is partitioned into a second space that includes and on the main surface of the partition plate. , One or more through holes are opened, the anode gas through the through holes, fuel cell characterized by a structure that flows from the second space to the first space. 2. The partition plate is provided with two or more through holes in a dispersed manner so as to be substantially uniform over the entire main surface of the partition plate. Fuel cell. 3. The installation position of the partition plate in the anode gas flow space of the external manifold is such that the ratio V / Q of the volume V of the battery stack to the volume Q of the first space is 15 or more and 40 or less. The fuel cell according to claim 1 or 2, wherein the fuel cell is selected at a position that defines the volume Q of the first space.