KR100744940B1 - A micro reformer and its manufacturing method - Google Patents

Abstract

An improved fuel reformer which can obtain a high efficiency reforming effect by accurately securing an etching depth of catalytic filters, and can improve the power output density of the fuel cell by smoothly supplying a reforming gas while accomplishing the miniaturization of the fuel cell in the case that the fuel reformer is mounted on a fuel cell, and a manufacturing method of the fuel reformer are provided. A manufacturing method of a fuel reformer for a fuel cell comprises the steps of: providing a substrate(10) with a predetermined size; forming a mask(50) of compensation patterns(52) in channel regions of the substrate such that the compensation patterns have a gap(d) corresponding to a gap between catalytic filters; etching the substrate; depositing SiO2 onto the substrate; and etching SiO2 of the substrate to remove the substrate of channel portions and form channels(20). The compensation patterns are formed in the form of a castle wall whose thickness is thinner than the thickness of pillars of the catalytic filters, and a gap between the compensation patterns is equal to that between the pillars of the catalytic filters to impart the same load as an etching load of the catalytic filters to the channels.

Description

Fuel reformer and its manufacturing method {A Micro Reformer and Its Manufacturing Method}

1 is a plan view showing the cover removed from the fuel reformer according to the prior art.

2 is a view showing the etching depth of the catalytic filter portion in the fuel reformer according to the prior art,

         a) is a sectional view taken along the line A-A of FIG. 1, b) is a side view in the direction "B" of FIG.

3 is a block diagram showing a mask used in a fuel reformer according to the prior art.

4 is a plan view of the substrate with the cover removed from the fuel reformer according to the present invention.

5 is a view showing the etching depth of the catalytic filter portion in the fuel reformer according to the present invention,

         a) is a sectional view taken along the line A-A of FIG. 1, b) is a side view in the direction "B" of FIG.

A) to e) of FIG. 6 are process flow diagrams showing step by step a method of manufacturing a fuel reformer according to the present invention.

7 is a block diagram showing a compensation pattern used in the fuel reformer according to the present invention.

       <Description of the symbols for the main parts of the drawings>

1 .... Fuel reformer according to the invention 10 .... Substrate

20 ... channel 22 .... channel bulkhead

30 .... catalytic filter 32 .... catalytic filter column

50 .... mask of the invention 50a .... compensation pattern

52 .... Compensation pattern Wall wall 62 .... SiO ₂ layer

200 ... conventional reformer 210 ... substrate

220 .... microchannel 230 ... catalyst

234 .... catalytic filter 234a ... catalytic filter column

238 .... conventional mask 240 .... residual part

C .... Spacing between catalyst filters d .... Channel area Column spacing

The present invention relates to a reformer used in a fuel cell, and more particularly, to accurately secure an etching depth of a catalyst filter for filling a catalyst therein, thereby preventing an increase in internal pressure during catalyst filling, thereby obtaining a high efficiency reforming effect. The present invention relates to an improved fuel reformer and a method of fabricating the same for achieving miniaturization of a fuel cell.

The small fuel cell can be implemented by direct methanol, which directly supplies methanol to the fuel electrode, and reformed hydrogen fuel cell (RHFC), which extracts hydrogen from methanol and injects the fuel into the fuel electrode. As the PEM (Polymer Electrode Membrane) method, hydrogen is used as fuel. Therefore, it has advantages in high output, power capacity that can be realized per unit volume, and no reactants other than water, but it also has disadvantages in miniaturization because a reformer must be added to the system.

As such, in order to obtain a high power output density of the fuel cell, a reformer for making the fuel gas into a gaseous fuel such as hydrogen gas is essential. Such a reformer includes an evaporation unit for vaporizing an aqueous methanol solution, and a reforming unit for converting methanol, which is a fuel, into hydrogen through a catalytic reaction at a temperature of 250 ° C. to 290 ° C.

This reformer is an endothermic reaction proceeds in the reforming unit, the reaction efficiency is good to maintain the temperature of the portion between 250 ℃ to 290 ℃.

Conventional reformer is a reforming catalyst is coated in the micro-channel constituting the reforming portion, the fuel gas such as methanol is reformed into hydrogen and carbon dioxide through the coated catalyst.

However, such conventional reformers have an inefficient problem in the process of reforming fuel gas. This is because the fuel gas reacts with the catalyst coating layer of a limited area, thereby lowering the conversion rate of the fuel gas to hydrogen.

In order to solve such a problem, the applicant has proposed a method of filling a catalyst into a channel of a reforming unit with Korean Patent Application No. 2006-15112 issued on February 16, 2006. As such, when the catalyst is filled in the flow path of the reforming unit, the reaction surface area is increased, and the hydrogen conversion rate of methanol is greatly increased. In addition, there is an advantage that the drive temperature of the reforming unit can be significantly lowered to 195 ~ 210 ℃.

As shown in FIG. 1, the conventional reformer 200 of the catalyst filling method includes a substrate 210 having a predetermined size, and forms a micro channel 220 formed on the substrate 210. A catalyst filter 234 formed to hold the catalyst 230 in 220 is provided.

In addition, the fuel gas passes through the catalyst 230 in the microchannel 220, including a particulate catalyst 230 filled in the channel 220 and a cover (not shown) covering the channel 220 to reform the fuel. It is to be achieved.

The conventional reformer 200 has a width W of about 500 μm and a depth of 300 μm. In addition, the catalyst filters 234 formed at the inlet and outlet sides of the microchannel 220 have a shape of a column 234a of 100 μm × 100 μm, respectively, and the interval C between the columns 234a is 2 to 10. It is about a micrometer.

And the conventional reformer 200 is formed between the micro-channel width (W) of 500㎛ as shown in Figure 3, between the pillars 234a of 100㎛ 100㎛ size and the interval (C) therebetween ) Is formed on the surface of the substrate 210 to form a mask 238 for forming the catalyst filter 234 to maintain 2 to 10㎛, and then to form the channel 220 and the catalyst filter 234 by etching.

Therefore, in the conventional structure, the channel 220 and the catalyst filter 234 are formed by etching portions except for the mask 238. In this process, the width W and the catalyst of the microchannel 220 are formed. Since the gap C between the pillars 234a of the filter 234 is largely different at a ratio of approximately 50: 1, the desired etching depth cannot be obtained at the portion between the pillars 234a of the catalytic filter 234. .

That is, when the depth of 300 μm is removed by etching at the 500 μm wide (W) point of the microchannel 220, as shown in FIG. 2 at the 2 to 10 μm interval C of the catalyst filter 234, Only a depth of approximately 150 μm is removed by etching and leaves a residual portion 240 that was not removed by etching.

This was a problem that the active etching of the etching solution could not be achieved at a narrow interval C between the pillars 234a of the catalyst filter 234, thereby preventing the etching of the desired depth per unit time as in the channel 220. .

Therefore, in the conventional fuel reformer 200, if the etching of the catalyst filter 234, which is not smoothly etched, is attempted to secure the depth C, the portion of the micro channel 220 forming the reforming portion is excessively excessive. There was a problem of being etched and etched beyond the desired depth.

Therefore, in the related art, it is not possible to secure a desired depth of 300 μm in the interval C between the pillars 234a of the catalyst filter 234, thereby causing a problem of greatly reducing the flow path of the fuel gas.

That is, when the reformer 200 is completed by filling the catalyst 230 in the microchannel 220 and then reforming the fuel gas, the flow path of the catalyst filter 234 is greatly reduced. Interfering with the smooth passage will result in unnecessary pressure rise inside the reformer 200. Therefore, in such a conventional structure, it is difficult to obtain an efficient reforming effect by preventing a smooth reforming action, and accordingly, there is a problem of degrading the performance of a fuel cell equipped with such a conventional fuel reformer 200.

The present invention is to solve the above conventional problems, the purpose is to ensure the etch depth of the catalyst filter accurately to prevent the increase of the internal pressure during the catalyst filling to ensure a smooth flow of fuel gas and reforming gas high efficiency It is to provide an improved fuel reformer and its manufacturing method to obtain a reforming effect of.

Another object of the present invention is to provide an improved fuel reformer and a method for manufacturing the same, when the fuel cell is mounted on a fuel cell to improve the power output density of the fuel cell by supplying a reformed gas while miniaturizing the fuel cell. have.

In order to achieve the above object, the present invention provides a reformer for a fuel cell,

Substrate of constant size;

A channel formed on the substrate;

A catalyst filter formed to hold a catalyst in the channel;

A particulate catalyst charged in the channel; And

And a cover covering the channel, wherein the depth between the catalyst filters is coincident with the depth of the channel.

In addition, the present invention provides a method of manufacturing a reformer for a fuel cell,

Providing a substrate of a predetermined size;

Forming a mask of a compensation pattern having an interval having a size corresponding to an interval between catalyst filters in a channel region of the substrate;

Etching the substrate;

Depositing SiO ₂ on the substrate; And

And etching the SiO ₂ of the substrate to remove the substrate in the channel portion and to form a channel.

In addition, the present invention preferably the compensation pattern is the width of the wall shape is thinner than the thickness of the pillar of the catalyst filter, the interval between them is equal to the interval between the catalyst filter and the etching load (etching load) of the catalyst filter It provides a method for producing a fuel reformer, characterized in that the same load is applied to the channel.

And the present invention preferably provides a method for producing a fuel reformer, characterized in that the compensation pattern is formed in the form of a checkerboard.

In another aspect, the present invention preferably provides a method for producing a fuel reformer, characterized in that the compensation pattern is formed in a width of 22㎛.

Hereinafter, a fuel reformer and a manufacturing method thereof according to the present invention will be described in more detail with reference to the accompanying drawings.

As shown in FIG. 4, the fuel reformer 1 according to the present invention forms a channel 20 and a catalyst filter 30 on the substrate 10, and the depth between the catalyst filters 30 is equal to the above. The structure corresponds to the depth of the channel 20.

In the fuel reformer 1 of the present invention, as shown in FIG. 5, the pillar 32 forming the catalyst filter 30 has a size of 100 μm × 100 μm, and an interval therebetween (C). ) Is maintained at 2 to 10 μm, while the depth of the gap C therebetween is maintained at a depth of 300 μm corresponding to the depth of the channel 20.

In addition, the fuel reformer 1 of the present invention has a size at which the partition wall 22 forming the channel 20 is at least thicker than the column 32 of the catalyst filter 32.

Therefore, the fuel reformer 1 of the present invention has a very small flow resistance as compared with the conventional process in the course of passing the fuel gas or the reforming gas through the catalyst filter 30, so that the fuel reformer 1 smoothly passes, and the fuel reformer 1 inside To effectively prevent the pressure rise.

Therefore, a high efficiency reforming effect can be obtained, the fuel cell can be miniaturized, and the power output density can be increased.

The method of manufacturing the fuel reformer 1 according to the present invention as described above is as follows.

First, a step of providing a substrate 10 having a predetermined size is performed, and as shown in FIG. 6A, corresponding to the interval C between the catalyst filters 30 in the channel 20 region of the substrate 10. Forming a mask 50 of the compensation pattern 50a having an etching interval d of the size is performed.

As shown in FIG. 7, the compensation pattern 50a of the mask 50 maintains the distance d between the wall walls 52 having a width of 22 μm in the channel 20 region. The purpose of the present invention is to provide an etching load such as the catalyst filter 30. Therefore, the compensation pattern 50a has a structure in which an etching gap d between the wall walls 52 is formed in a checkerboard shape with a thickness of 2 to 10 μm.

In this case, the size of the wall shape 52 formed in the compensation pattern 50a is very small compared to the size of the pillar 32 of the catalyst filter 30.

That is, the width of the wall shape 52 of the compensation pattern 50a has a size of 22 μm, whereas the size of the pillar 32 of the catalyst filter 30 has a size of 100 μm × 100 μm.

The compensation pattern 50a is formed to have a size corresponding to the distance C between the catalyst filters 30 with an etching interval d of 2 to 10 μm.

As described above, when the compensation pattern 50a is to be formed on one side of the substrate 10, the photolithography is performed through a photo process with the improved compensation pattern 50a on the substrate 10. Do photolithography.

Next, as shown in FIG. 6B), the step of etching the substrate 10 is performed.

In this case, the substrate 10 is subjected to an dry etching process by performing an inductively-coupled plasma (ICP) process.

After the ICP dry etching process, as shown in Figure 6c), as shown in Figure 6c, a plurality of checkered wall-shaped wall 52 is formed in the channel 20 forming region, the interval (d), That is, in the interval d between 2 to 10 μm, the portion is etched to a depth of 300 μm. In this case, the depth (C) depth between the pillars 32 on the side of the catalyst filter 30 is maintained at 300 μm in the same shape as the depth between the wall walls 52 on the side of the channel 20.

The reason is that the distance d between the wall walls 52 formed in the channel 20 portion is 2 to 10 μm, and is formed in the same size as the distance C between the pillars of the catalyst filter 30. This is because the same load as the etching load of the gap C between the pillars 32 can be applied to the region of the channel 20. That is, although the loading effect of 50: 1 is different from the initial channel region and the partition wall in the related art, the etching depth can be adjusted by lowering to 8: 1 by the current process method.

Next, as shown in FIG. 6D), the SiO ₂ layer 62 is grown by thermal oxidation on the wall shapes 52 on the channel 20 side.

In this case, the SiO ₂ The growth thickness of the layer 62 is approximately 1 to 2 μm, and SiO ₂ is formed on the surface of the pillar 32 of the catalyst filter 30 including the wall-shaped 52 on the channel 20 side. Layer 62 is grown and formed.

Next, the present invention includes etching the SiO ₂ of the substrate 10 to remove the lower substrate of the compensation pattern 50a formed in the channel 20 region and to form the channel 20.

In this step, SiO _{2 is} formed on the wall 52 of the region of the channel 20 through a thermal oxidation process. When the layer 62 is grown, the SiO ₂ layer 62 may be removed by wet etching using a solution such as NH ₄ + HF or HF.

In this case, each of the wall shapes 52 in the channel 20 region of the substrate 10 has its bottom portion etched away more than the top side of the wall wall 52 so as to be separated and removed from the substrate 10. do.

In this case, the wall shape 52 of the channel 20 region has a width of 22 μm, while the size of the pillar 32 of the catalyst filter 30 has a size of 100 μm × 100 μm.

Therefore, the wall walls 52 of the region of the channel 20 are etched by the wet etchant and separated from the substrate 10 in a lift-off manner to be lifted from the substrate 10. Since the portion 30 has a relatively thick thickness of the pillar 32, the shape of the pillar 32 is maintained without being separated from the substrate 10 even when the lower portion of the pillar 32 of the catalyst filter 30 is partially etched.

As a result, as shown in FIG. 6E, the substrate 10 has a width W of 500 μm and a channel 20 having a depth of 300 μm.

According to the present invention as described above, in the process of forming the channel 20 and the catalyst filter 30 of the substrate, by maintaining the load in the etching process of the channel 20 portion and the catalyst filter 30 in the same channel The same etching depth can be obtained in the space C portion between the portion 20 and the catalyst filter 30.

In the fuel reformer 1 obtained through the process of the present invention, as shown in FIGS. 5A and 5B, the depth of the channel 20 portion of the substrate 10 is equal to the distance between the catalyst filters 30. To coincide with the depth of C) to fill the catalyst in the channel 20, and then to carry out the reforming action to prevent excessive pressure increase inside the channel 20.

Accordingly, the present invention is effective in preventing the outflow of the catalyst charged in the channel 20, while having a compact structure and obtaining a high efficiency reforming effect.

As described above, according to the present invention, the etching depth of the catalyst filter can be precisely secured according to the channel depth of the substrate, thereby preventing the internal gas pressure from increasing when the catalyst is filled in the channel, thereby ensuring a smooth flow of the fuel gas and the reforming gas. As a result, a high-efficiency reforming effect can be obtained.

In addition, since the present invention can achieve a compact structure of the reformer when it is mounted and used in a fuel cell, the fuel cell can be miniaturized, and accordingly, the reformed gas can be smoothly supplied to the fuel cell to supply power to the fuel cell. The improved effect can be obtained to greatly improve the power density.

While the invention has been shown and described with respect to specific embodiments thereof, it has been described by way of example only to illustrate the invention, and is not intended to limit the invention to this particular structure. Those skilled in the art will appreciate that various modifications and changes of the present invention can be made without departing from the spirit and scope of the invention as set forth in the claims below. Nevertheless, it will be clearly understood that all such modifications and variations are included within the scope of the present invention.

Claims (5)

In a reformer for a fuel cell, Substrate of constant size; A channel formed on the substrate; A catalyst filter formed to hold a catalyst in the channel; A particulate catalyst charged in the channel; And And a cover covering the channel, wherein a depth between the catalyst filters is equal to a depth of the channel. In the method of manufacturing a reformer for a fuel cell, Providing a substrate of a predetermined size; Forming a mask of a compensation pattern having an interval having a size corresponding to an interval between catalyst filters in a channel region of the substrate; Etching the substrate; Depositing SiO ₂ on the substrate; And Etching SiO ₂ of the substrate to remove the substrate of the channel portion and form a channel. 3. The method of claim 2, wherein the thickness of the wall shape is thinner than the thickness of the pillar of the catalyst filter, the interval between them is equal to the interval between the pillar of the catalyst filter and the etching load (etching load) of the catalyst filter Method for producing a fuel reformer, characterized in that to give the same load to the channel The method of claim 3, wherein the compensation pattern is formed in a checkerboard shape. The method of claim 3, wherein the compensation pattern has a width of 22 μm.

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