JP2021099270A - Method for evaluating structure of catalyst carrier for fuel cells - Google Patents

Abstract

To provide a method for evaluating the structure of a catalyst carrier for fuel cells, with which it is possible to quantitatively evaluate the structure of an open hole.SOLUTION: A method for evaluating the structure of a catalyst carrier for fuel cells according to the present invention comprises: a step for stacking a plurality of unprocessed cross-sectional images one on another, creating the unprocessed three-dimensional image of a catalyst carrier, stacking a plurality of hole-filled cross sectional images one on another and creating the hole-filled three-dimensional image of the catalyst carrier; a step for executing the exclusive OR and negative OR operations of the attribute of each element of the unprocessed three-dimensional image and the attribute of each element of the hole-filled three-dimensional image located at the same coordinate as said each element, and extracting an element that represents a pore and an element that represents the periphery; a step for determining that an element, out of the elements representing the pore, which adjoins an element representing the periphery in the unprocessed three-dimensional image is an element representing an entry to the pore; and a step for performing a width priority search of an element structure that represents the pore included in the unprocessed three-dimensional image and thereby acquiring the number of open holes and the distance thereto.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for evaluating the structure of a catalyst carrier for a fuel cell for evaluating the structure of through holes.

In recent years, fuel cells have been adopted, for example, as power sources for automobiles and home cogeneration. A factor that determines the power generation performance of a fuel cell is the structure of the catalyst carrier that constitutes the catalyst layer. Therefore, in a fuel cell, it is required that the catalyst carrier has a desired structure so that the required power generation performance can be obtained. Therefore, there is a need for a structure evaluation method that accurately evaluates whether or not the structure of the produced catalyst carrier has a desired structure.

As a method for evaluating the structure of the catalyst carrier, for example, an image of the surface of the catalyst carrier taken by an electron microscope is input to an arithmetic processing apparatus, and image size conversion, a threshold value for binarization processing, and expansion for noise removal are performed. After inputting parameters such as the number of treatments / shrinkage treatments and the maximum / minimum values of the size of the extracted element, binarization treatment, noise removal (expansion / contraction treatment), and labeling treatment are used to extract pore candidates. , A method for analyzing a catalyst structure that extracts pores is known (Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-102467

From the results of examining the structure of the catalyst carrier that determines the power generation performance of the fuel cell, it is considered that the gas diffusibility and drainage property are improved and the power generation performance is improved, especially by penetrating the pores existing in the catalyst carrier. ing. However, even if the catalyst carrier is made so that the through hole is formed, the power generation performance is superior or inferior depending on the structure of the through hole, and in some cases, the power generation is higher than that of the catalyst carrier having the structure without the through hole. Performance may be reduced.

Therefore, in order to develop a catalyst carrier capable of obtaining high power generation performance of a fuel cell, a method of quantitatively evaluating the three-dimensional structure of the through hole of the catalyst carrier, which causes superiority or inferiority in power generation performance, is required. .. On the other hand, in the method for analyzing the catalyst structure described in Patent Document 1, the number of pores, the pore diameter, and the pore area can be obtained from the image of the surface of the catalyst carrier taken by an electron microscope. It is difficult to quantitatively evaluate the three-dimensional structure of the through-holes of the carrier.

The present invention has been made in view of these points, and an object of the present invention is to provide a method for evaluating the structure of a catalyst carrier for a fuel cell, which can quantitatively evaluate the structure of through holes. There is.

In order to solve the above problems, the structural evaluation method of the catalyst carrier for a fuel cell of the present invention includes an untreated cross-sectional image acquisition step of acquiring a plurality of untreated cross-sectional images of the catalyst carrier and a plurality of untreated cross-sectional images. A three-dimensional image composed of elements that are structural units by stacking the hole-filled cross-sectional image creation step of creating a plurality of hole-filled cross-sectional images by filling the pore regions of the above and the above-mentioned multiple unprocessed cross-sectional images. By performing the constructing process, the attribute of each element representing the filling portion inside the catalyst carrier is set to "1", and each element representing the pores inside the catalyst carrier and the outer peripheral portion surrounding the catalyst carrier. The unprocessed three-dimensional image creating step of creating the untreated three-dimensional image of the catalyst carrier in which the attribute of is set to "0", and the plurality of filled-in-filled cross-sectional images are laminated and composed of elements which are structural units. By performing the process of constructing the three-dimensional image, the attribute of each element representing the filling portion and the filling portion inside the catalyst carrier is set to "1", and each element representing the outer peripheral portion surrounding the catalyst carrier is set to "1". The hole-filled three-dimensional image creation step for creating the hole-filled three-dimensional image of the catalyst carrier in which the attribute of is set to "0", the attribute of each element of the unprocessed three-dimensional image, and the same coordinates as the element. An exclusive logical sum (XOR) operation with the attributes of each element of the filled-in 3D image located in is executed, and based on the result of the exclusive logical sum operation, among the elements of the unprocessed 3D image, the above Negative logic between the first calculation step of extracting the elements representing the pores, the attributes of each element of the unprocessed 3D image, and the attributes of each element of the filled-in 3D image located at the same coordinates as each element. A second calculation step of executing a sum (NOR) operation and extracting an element representing the outer peripheral portion from the elements of the unprocessed three-dimensional image based on the result of the negative logical sum operation, and the unprocessed three-dimensional image. In the entrance portion determination step of determining an element adjacent to the element representing the outer peripheral portion among the elements representing the pores as an element representing the entrance portion of the pores, and the above-mentioned unprocessed three-dimensional image. A through-hole information acquisition step of acquiring the number and distance of through-holes penetrating from one of the entrances of the pores to the other entrances by performing a width-priority search of an element structure representing the pores is provided. It is characterized by that.

According to the present invention, the structure of through holes of a catalyst carrier for a fuel cell can be quantitatively evaluated.

It is a process diagram which shows typically the unprocessed cross-sectional image acquisition process, the hole-filled cross-sectional image making process, the unprocessed three-dimensional image making process, and the hole-filled three-dimensional image making process in an example of embodiment. It is a figure which shows typically the element structure which represents a plurality of pores in the TEM three-dimensional image of a catalyst carrier. In the element structure representing a plurality of pores shown in FIG. 2, the element structure representing the pores including the element representing the entrance of the pore selected as the starting element for starting the breadth-first search and the related information of the breadth-first search are shown. It is a figure. It is a figure which shows typically the queue in the case of performing the breadth-first search of the element structure representing the pore shown in FIG. 3 in time series. It is a graph which shows the evaluation result of the power generation performance of the fuel cell for each catalyst carrier. It is a figure which shows typically the structure evaluation method of the catalyst carrier for a conventional fuel cell. It is a graph which shows typically the evaluation result by the structure evaluation method of the catalyst carrier for a fuel cell of an Example.

Hereinafter, a method for evaluating the structure of the catalyst carrier for a fuel cell according to the embodiment of the present invention will be described.

The structural evaluation method of the catalyst carrier for the fuel cell of the embodiment includes a step of acquiring a plurality of untreated cross-sectional images of the catalyst carrier and a pore region of the plurality of untreated cross-sectional images. By performing the hole-filled cross-sectional image creation step of creating a plurality of hole-filled cross-sectional images and the process of superimposing the plurality of unprocessed cross-sectional images to construct a three-dimensional image composed of elements that are structural units. , The attribute of each element representing the filling portion inside the catalyst carrier is set to "1", and the attribute of each element representing the pores inside the catalyst carrier and the outer peripheral portion surrounding the catalyst carrier is set to "0". The set untreated three-dimensional image creation step of creating the untreated three-dimensional image of the catalyst carrier and the plurality of hole-filled cross-sectional images are laminated to construct a three-dimensional image composed of elements that are structural units. The attribute of each element representing the filling portion and the filling portion inside the catalyst carrier is set to "1", and the attribute of each element representing the outer peripheral portion surrounding the catalyst carrier is set to "0". The set hole-filled three-dimensional image creation step for creating a hole-filled three-dimensional image of the catalyst carrier, the attributes of each element of the unprocessed three-dimensional image, and the hole-filled 3 located at the same coordinates as each element. An exclusive logical sum (XOR) operation with the attributes of each element of the dimensional image is executed, and based on the result of the exclusive logical sum operation, the element representing the pore is extracted from the elements of the unprocessed three-dimensional image. Performs a negative logical sum (NOR) operation between the first calculation step and the attributes of each element of the unprocessed three-dimensional image and the attributes of each element of the filled-in three-dimensional image located at the same coordinates as each element. Then, based on the result of the negative logical sum operation, the second arithmetic step of extracting the element representing the outer peripheral portion from the elements of the unprocessed three-dimensional image and the unprocessed three-dimensional image represent the pores. Of the elements, an element adjacent to the element representing the outer peripheral portion is determined to be an element representing the entrance portion of the pores, and an entrance portion determination step, and an element structure representing the pores included in the unprocessed three-dimensional image. It is characterized by comprising a through hole information acquisition step of acquiring the number and distance of through holes penetrating from one entrance portion of one of the pores to the other entrance portion by performing a width priority search.

First, an example of the structure evaluation method of the catalyst carrier for the fuel cell of the embodiment will be described. Here, FIG. 1 is a process diagram schematically showing an unprocessed cross-sectional image acquisition step, a hole-filled cross-sectional image creation step, an unprocessed three-dimensional image creation step, and a hole-filled three-dimensional image creation step in an example of the embodiment. is there. FIG. 2 is a diagram schematically showing an element structure representing a plurality of pores in a TEM three-dimensional image of a catalyst carrier. FIG. 3 shows an element structure representing a pore and a breadth-first search including an element representing the entrance of the pore selected as a starting element for starting a breadth-first search in the element structure representing a plurality of pores shown in FIG. It is a figure which shows the related information. FIG. 4 is a diagram schematically showing a queue in the case of performing a breadth-first search of the element structure representing the pores shown in FIG. 3 in chronological order.

In the structural evaluation method of this example, first, as shown in FIG. 1, a plurality of TEM cross-sectional images (unprocessed cross-sectional images) 10T of the catalyst carrier for the fuel cell to be evaluated are acquired (unprocessed cross-sectional image acquisition step). .. Specifically, a plurality of TEM cross-sectional images 10T are obtained by observing each of a plurality of cross sections when the catalyst carrier is sliced on a predetermined plane at predetermined intervals with a TEM (transmission electron microscope). The plurality of TEM cross-sectional images 10T show a filling region 1 in which a portion filled with the material inside the catalyst carrier is displayed, a pore region 2 in which pores inside the catalyst carrier are displayed, and a portion surrounding the catalyst carrier. Includes the outer peripheral region 3 in which is displayed.

Next, as shown in FIG. 1, a plurality of hole-filled cross-sectional images 10A are created by filling the pore regions 2 of the plurality of TEM cross-sectional images 10T (hole-filled cross-sectional image creating step). Specifically, by modifying the pore region 2 in the plurality of TEM cross-sectional images 10T to the fill-in-the-blank region 4 representing the portion in which the pores inside the catalyst carrier are filled, a plurality of fill-in-the-blank cross-sectional images 10A are created. To do. The plurality of hole-filled cross-sectional images 10A include a filling area 1, a hole-filling area 4, and an outer peripheral area 3.

Next, as shown in FIG. 1, a process of stacking a plurality of TEM cross-sectional images 10T according to conditions such as acquisition positions of these cross-sectional images to construct a three-dimensional image composed of elements that are structural units is performed. To create a TEM three-dimensional image 100T (unprocessed three-dimensional image) of the catalyst carrier from a plurality of TEM cross-sectional images 10T (unprocessed three-dimensional image creation step). The TEM three-dimensional image 100T of the catalyst carrier is composed of elements that are structural units, and includes a portion representing a filling portion filled with a material inside the catalyst carrier, a portion representing pores inside the catalyst carrier, and a catalyst. It includes a portion representing an outer peripheral portion surrounding the carrier. The attributes of each element of the TEM three-dimensional image 100T of the catalyst carrier are binarized based on the pixels of a plurality of TEM cross-sectional images 10T, and the attributes of each element representing the filling portion are set to "1", and the pores and the pores are set. The attribute of each element representing the outer peripheral portion is set to "0". The position of the element is specified by three-dimensional coordinates, and the distance between the elements can be calculated from the position of each element.

Next, as shown in FIG. 1, a process of stacking a plurality of filled-in-filled cross-sectional images 10A according to conditions such as acquisition positions of a plurality of TEM cross-sectional images 10T to construct a three-dimensional image composed of elements that are structural units. By performing the above, a hole-filled three-dimensional image 100A of the catalyst carrier is created from the plurality of hole-filled cross-sectional images 10A (hole-filled three-dimensional image creation step). The hole-filled three-dimensional image 100A of the catalyst carrier is composed of elements that are structural units, and the portion representing the filling portion filled with the material inside the catalyst carrier and the pores inside the catalyst carrier are filled with holes. It includes a portion representing a hole filling portion and a portion representing an outer peripheral portion surrounding the catalyst carrier. The attributes of each element of the fill-in-the-blank three-dimensional image 100A of the catalyst carrier are binarized based on the pixels of the plurality of fill-in-the-blank cross-sectional images 10A, and the attributes of each element representing the filling portion and the filling portion are set to "1". The attribute of each element representing the outer peripheral portion is set to "0". The position of the element is specified by three-dimensional coordinates, and the distance between the elements can be calculated from the position of each element.

Next, an exclusive OR (XOR) operation is executed between the attributes of each element of the TEM 3D image 100T and the attributes of each element of the filled-in 3D image 100A located at the same coordinates as the elements, and the exclusive OR is executed. Based on the result of the sum calculation, the element representing the pores is extracted from the elements of the TEM three-dimensional image 100T (first calculation step). Specifically, when this exclusive OR operation is executed, the attribute "0" of each element representing the pores in the TEM three-dimensional image 100T and the attribute "1" of each element representing the fill-in-the-blank portion in the filled-in-filled three-dimensional image 100A. Since only the result of the exclusive OR operation with is "1", only the elements located at the coordinates where the result of the exclusive OR operation is "1" among the elements of the TEM 3D image 100T are pores. Is extracted as an element representing.

Next, a NOR operation is performed between the attributes of each element of the TEM 3D image 100T and the attributes of each element of the filled-in 3D image 100A located at the same coordinates as each element, and the NOR operation is performed. Based on the result of, the element representing the outer peripheral portion is extracted from the elements of the TEM three-dimensional image 100T, and the attribute of the element representing the outer peripheral portion is changed from "0" to "2" (second calculation step). Specifically, when this exclusive OR operation is executed, the attribute "0" of each element representing the outer peripheral portion in the TEM three-dimensional image 100T and the attribute "0" of each element representing the outer peripheral portion in the filled-in three-dimensional image 100A. Since only the result of the exclusive OR operation with is "1", only the element located at the coordinate where the result of the exclusive OR operation is "1" among the elements of the TEM 3D image 100T is the outer peripheral portion. The attribute of the element representing the outer peripheral portion is changed from "0" to "2".

Next, in the TEM three-dimensional image 100T, among the elements representing the pores, the elements adjacent to the elements representing the outer peripheral portion are determined to be the elements representing the entrance portion of the pores, and for each element representing the entrance portion of the pores. And assign IDs that can be identified from each other (entrance determination step). Specifically, at this stage, in the element of the TEM three-dimensional image 100T, the attribute of the element representing the pore is set to "0", and the attribute of each element representing the filling portion is set to "1". Since the attribute of the element representing the outer peripheral portion is set to "2" above, the element adjacent to the element having the attribute "2" among the elements having the attribute "0" represents the entrance portion of the pore. It is determined that it is an element, and an ID that can be distinguished from each other is assigned to each element representing the entrance of the pore.

Next, by performing a breadth-first search of the element structure representing a plurality of pores included in the TEM three-dimensional image 100T, the number and distance of through holes penetrating from one inlet portion of the pore to the other inlet portion are acquired. (Through hole information acquisition process).

In the through hole information acquisition step, first, in the element structure representing a plurality of pores in the TEM three-dimensional image 100T shown in FIG. 2, breadth-first search is started from the IDs of the elements representing the entrance portions of the plurality of pores. Select the ID "A" of the element to be the start element. As a result, an element representing the entrance of the pore whose ID is "A" is selected as the starting element. Subsequently, as shown in FIGS. 3 and 4, a breadth-first search of the element structure representing the pore including the starting element (element representing the entrance portion of the pore whose ID is “A”) is performed. Hereinafter, the breadth-first search of the element structure representing the pores will be specifically described with reference to FIGS. 3 and 4.

(Breadth-first search of element structure representing pores)
In the breadth-first search of the element structure representing the pore, first, as shown in FIG. 3, in the element structure representing the pore including the start element (element representing the entrance portion of the pore whose ID is "A"), the start element After setting the distance information of to "0", as shown in step 1 of FIG. 4, the start element having the ID "A" is added to the search candidate list of the queue (queue) and set to the current element. ..

Next, as shown in FIG. 3, an unsearched element (an element representing a pore that has not been searched) adjacent to the current element having an ID of "A" is searched, and an unsearched element having an ID of "a" is searched. The element is found, and the distance information of the unsearched element is set to "distance information of the current element + 1", that is, "1". After that, as shown in step 2 of FIG. 4, the unsearched element is added to the search candidate list of the queue from the back, and the current element having the ID "A" is set as the searched element from the search candidate list of the queue to the searched list. After moving, by selecting the unsearched element from the front of the search candidate list of the queue, the unsearched element having the ID "a" is selected and set as a new current element.

Next, as shown in FIG. 3, an unsearched element adjacent to the current element having an ID of "a" is searched, an unsearched element having an ID of "b" is found, and the distance information of the unsearched element is obtained. Set to "distance information of current element + 1", that is, "2". After that, as shown in step 3 of FIG. 4, the unsearched element is added to the search candidate list of the queue from the back, and the current element having the ID "a" is set as the searched element from the search candidate list of the queue to the searched list. After moving, by selecting the unsearched element from the front of the search candidate list of the queue, the unsearched element having the ID "b" is selected and set as a new current element.

Next, as shown in FIG. 3, the unsearched elements adjacent to the current element having the ID "b" are searched, the unsearched elements having the IDs "c" and "d" are found, and these unsearched elements are searched. The distance information of the element is set to "distance information of the current element + 1", that is, "3". After that, as shown in step 4 of FIG. 4, these unsearched elements are added to the search candidate list of the queue from the back, and the current element having the ID "b" is set as the searched element and the searched list is searched from the search candidate list of the queue. By selecting an unsearched element from the front of the search candidate list of the queue after moving to, the unsearched element having the ID "c" is selected and set as a new current element.

Next, as shown in FIG. 3, an unsearched element adjacent to the current element having an ID of "c" is searched, an unsearched element having an ID of "e" is found, and the distance information of the unsearched element is obtained. Set to "distance information of current element + 1", that is, "4". After that, as shown in step 5 of FIG. 4, the unsearched element is added to the search candidate list of the queue from the back, and the current element having the ID “c” is set as the searched element from the search candidate list of the queue to the searched list. After moving, by selecting the unsearched element from the front of the search candidate list of the queue, the unsearched element having the ID "d" is selected and set as a new current element.

Next, as shown in FIG. 3, an unsearched element adjacent to the current element having an ID of "d" is searched, and as an unsearched element, an element representing the entrance of the pore having an ID of "B" is used. Find and set the distance information of the element at the entrance to "distance information of the current element + 1", that is, "4". After that, as shown in step 6 of FIG. 4, the element of the entrance portion is added to the search candidate list of the queue from the back, and the current element having the ID "d" is set as the searched element and the search list is searched from the search candidate list of the queue. By selecting an unsearched element from the front of the search candidate list of the queue after moving to, the unsearched element having the ID "e" is selected and set as a new current element. Further, the through hole information 1 including the distance information "4" of the element of the entrance portion whose ID is "B" found in the search is output as the distance information of the through hole.

Next, as shown in FIG. 3, the unsearched elements adjacent to the current element having the ID "e" are searched, the unsearched elements having the IDs "f" and "g" are found, and these unsearched elements are searched. The distance information of the element is set to "distance information of the current element + 1", that is, "5". After that, as shown in step 7 of FIG. 4, these unsearched elements are added to the search candidate list of the queue from the back, and the current element having the ID "e" is set as the searched element and the searched list is searched from the search candidate list of the queue. By selecting the unsearched element from the front of the search candidate list of the queue after moving to, the unsearched element having the ID "B" is selected and set as a new current element.

Next, as shown in FIG. 3, even if the unsearched element adjacent to the current element having the ID “B” is searched, the unsearched element cannot be found. Therefore, as shown in step 8 of FIG. By moving the current element with the ID "B" from the search candidate list of the queue to the searched list as the searched element, and then selecting the unsearched element from the front of the search candidate list of the queue, the ID becomes ". Select the unsearched element of "f" and set it as a new current element.

Next, as shown in FIG. 3, an unsearched element adjacent to the current element having an ID of "f" is searched, an unsearched element having an ID of "h" is found, and the distance information of the unsearched element is obtained. Set to "distance information of current element + 1", that is, "6". After that, as shown in step 9 of FIG. 4, the unsearched element is added to the search candidate list of the queue from the back, and the current element having the ID "f" is set as the searched element from the search candidate list of the queue to the searched list. After moving, by selecting the unsearched element from the front of the search candidate list of the queue, the unsearched element having the ID "g" is selected and set as a new current element. The unsearched element having an ID of "h" is a terminal element in the element structure representing the pore, but is not an element representing the entrance portion of the pore. Therefore, the distance of the unsearched element having an ID of "h". The through hole information including the information as the through hole distance information is not output.

Next, as shown in FIG. 3, an unsearched element adjacent to the current element having an ID of "g" is searched, and as an unsearched element, an element representing a pore having an ID of "j" and an ID having an ID of "j" are ". The element representing the entrance portion of the pore of "C" is found, and the distance information of the element of the pore and the element of the entrance portion is set to "distance information of the current element +1", that is, "6". After that, as shown in step 10 of FIG. 4, these elements of the pores and the elements of the entrance are added from the back to the search candidate list of the queue, and the current element having the ID "g" is queued as the searched element. By moving from the search candidate list of the above to the searched list and then selecting the unsearched element from the front of the search candidate list of the queue, the unsearched element with the ID "h" is selected and set as a new current element. To do. Further, the through hole information 2 including the distance information “6” of the element at the entrance portion whose ID is “C” found in the search is output as the through hole distance information.

Next, as shown in FIG. 3, even if the unsearched element adjacent to the current element having the ID “h” is searched, the unsearched element cannot be found. Therefore, as shown in step 11 of FIG. By moving the current element with the ID "h" from the search candidate list of the queue to the searched list as the searched element, and then selecting the unsearched element from the front of the search candidate list of the queue, the ID becomes ". Select the unsearched element of "j" and set it as a new current element.

Next, as shown in FIG. 3, an unsearched element adjacent to the current element having an ID of "j" is searched, and as an unsearched element, an element representing the entrance of the pore having an ID of "D" is used. Find and set the distance information of the element at the entrance to "distance information of the current element + 1", that is, "7". After that, as shown in step 12 of FIG. 4, the element of the entrance portion is added to the search candidate list of the queue from the back, and the current element having the ID "j" is set as the searched element and the search list is searched from the search candidate list of the queue. By selecting an unsearched element from the front of the search candidate list of the queue after moving to, the unsearched element having the ID "C" is selected and set as a new current element. Further, the through hole information 3 including the distance information "7" of the element at the entrance portion whose ID is "D" found in the search is output as the through hole distance information.

Next, as shown in FIG. 3, even if the unsearched element adjacent to the current element having the ID “C” is searched, the unsearched element cannot be found. Therefore, as shown in step 13 of FIG. By moving the current element with the ID "C" from the search candidate list of the queue to the searched list as the searched element, and then selecting the unsearched element from the front of the search candidate list of the queue, the ID becomes ". Select the unsearched element of "D" and set it as a new current element.

Next, as shown in FIG. 3, even if the unsearched element adjacent to the current element having the ID “D” is searched, the unsearched element cannot be found. Therefore, as shown in step 14 of FIG. In addition, the current element whose ID is "D" is moved from the search candidate list of the queue to the searched list as the searched element. As a result, there are no unsearched elements in the search candidate list of the queue, so the search ends.

By performing a breadth-first search of the element structure representing the pores including the start element (element representing the entrance portion of the pore whose ID is "A") as described above, the said through hole information 1 to 3 Information such as whether or not the pore is a through hole, the distance of the through hole, and the number of branches of the through hole can be obtained. In the breadth-first search, the shortest distance from one entrance of the pore to the other entrance can be obtained as the distance of the through hole.

In the through-hole information acquisition step, in the element structure representing a plurality of pores in the TEM three-dimensional image 100T shown in FIG. 2, a breadth-first search is started from among the IDs of the elements representing the entrances of the plurality of pores. By selecting the IDs of the elements to be used in order, breadth-first search is performed for each of the element structures representing the plurality of pores. As a result, regarding the catalyst carrier for the fuel cell to be evaluated, the three-dimensional image was constructed on the TEM three-dimensional image 100T, the number of pore inlets, the number of through holes, the distance of each through hole, and each through hole. Quantitative information on the structure of through-holes and pores, such as the number of branches and the number of non-penetrating pores, can be obtained.

Therefore, in the structure evaluation method of the catalyst carrier for the fuel cell of this example, the structures of the through holes and the pores are quantitatively evaluated by acquiring the quantitative information of the structures of the through holes and the pores. can do.

Therefore, according to the method for evaluating the structure of the catalyst carrier for the fuel cell of the embodiment, the structure of the through hole of the catalyst carrier for the fuel cell can be quantitatively evaluated as in this example. Therefore, the power generation performance of the fuel cell can be estimated based on the quantitative evaluation of the structure of the through hole.

Subsequently, the process conditions and the like in the structural evaluation method of the catalyst carrier for the fuel cell of the embodiment will be described in detail.

As a method of acquiring a plurality of untreated cross-sectional images of the catalyst carrier in the untreated cross-sectional image acquisition step, an untreated three-dimensional image capable of performing a width priority search of an element structure representing a pore in the through hole information acquisition step. It is not particularly limited as long as a plurality of untreated cross-sectional images capable of constructing the above can be obtained, but for example, as in the above example, a plurality of cross-sections when the catalyst carrier is sliced by a predetermined plane at predetermined intervals are TEM (transmission electron microscope). A method of obtaining a plurality of TEM cross-sectional images by observing each of them can be mentioned.

In the step of creating the hole-filled cross-sectional image, specifically, as in the above example, the pore region in which the pores inside the catalyst carrier in the plurality of untreated cross-sectional images are displayed is formed inside the catalyst carrier. A plurality of hole-filled cross-sectional images are created by modifying the hole-filled area to represent the part where the pores are filled.

In the through hole information acquisition step, as in the above example, the procedure for performing a breadth-first search for the element structure representing the pores included in the untreated three-dimensional image is as follows.

(1) In the element structure representing a plurality of pores in the untreated three-dimensional image of the catalyst carrier, the breadth-first search is started from the IDs of the elements representing the entrances of the plurality of pores identified by the IDs. Select the ID of the element to be the element.
(2) In the element structure representing the pores including the start element (the element representing the entrance of the pore whose ID is selected), the distance information of the start element is set to "0", and then the start element is queued ( In addition to the search candidate list of the queue), and set it in the current element.
(3) When an unsearched element (an element representing a pore that has not been searched) adjacent to the periphery of the current element is searched and an unsearched element is found, the distance information of the unsearched element is used as the "current element". Distance information +1 ”. After that, the unsearched element is added to the search candidate list of the queue from the back, the current element is moved from the search candidate list of the queue to the searched list as the searched element, and then the unsearched element is moved from the front of the search candidate list of the queue. By selecting, the unsearched element is selected and set as a new current element.
(4) When searching for an unsearched element adjacent to the periphery of the current element, if an element representing the entrance portion of the pore different from the starting element is found as the unsearched element, the element of the entrance portion is found. Set the distance information to "distance information of the current element + 1". After that, the through-hole information including the distance information of the element of the inlet portion as the distance information of the through-hole is output.
(5) Search for unsearched elements adjacent to the current element, and if the unsearched element cannot be found, move the current element as a searched element from the search candidate list of the queue to the searched list. By selecting an unsearched element from the front of the search candidate list of the queue, the unsearched element is selected and set as a new current element.
(6) When there are no unsearched elements in the search candidate list of the queue, the search ends.

Hereinafter, embodiments according to the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Comparison example]
As a comparative example, a method for evaluating the structure of a conventional catalyst carrier for a fuel cell will be described.
FIG. 5 is a graph showing the evaluation results of the power generation performance of the fuel cell for each catalyst carrier. FIG. 6 is a diagram schematically showing a method for evaluating the structure of a conventional catalyst carrier for a fuel cell.

In the conventional method for evaluating the structure of a catalyst carrier for a fuel cell, the structure of the catalyst carrier that is a factor that determines the power generation performance of the fuel cell using the catalyst carrier 1 and the catalyst carrier 2 as the catalyst layer as shown in FIG. 5 is evaluated. Therefore, as shown in FIG. 6, a qualitative evaluation based on the appearance observation was performed. Specifically, based on appearance observation using an electron microscope or the like, the catalyst carrier 1 has many pores and the distance between the through holes seems to be short. Therefore, the power generation performance of the fuel cell using the catalyst carrier 1 as the catalyst layer is high. It was evaluated that the power generation performance of the fuel cell using the catalyst carrier 2 as the catalyst layer would be high because the catalyst carrier 2 had few pores and the distance between the through holes seemed to be long.

[Example]
A method for evaluating the structure of the catalyst carrier for the fuel cell of the example will be described.
7 (a) to 7 (c) are graphs schematically showing the evaluation results by the structural evaluation method of the catalyst carrier for the fuel cell of the example.

In the method for evaluating the structure of the catalyst carrier for the fuel cell of the embodiment, for the catalyst carrier 1 and the catalyst carrier 2, for example, as shown in FIG. 7A, after determining the number of pore inlets, the catalyst carrier 1 and the catalyst carrier 2 are further evaluated. , 7 (b) and 7 (c), a histogram of the number of through-holes penetrating from one inlet to the other of the pores, and the distance of the through-holes (distance of through-holes). (Histogram showing the number of through holes for each class) was obtained. As a result, the structures of the through holes of the catalyst carrier 1 and the catalyst carrier 2 could be quantitatively evaluated. Further, the quantitative evaluation of the structure of these through holes could be evaluated in association with the power generation performance of the fuel cell using the catalyst carrier 1 and the catalyst carrier 2 as the catalyst layer.

Although the embodiments according to the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various aspects are described within the scope of the claims as long as the spirit of the present invention is not deviated. It is possible to make design changes.

10T TEM cross-sectional image 10A Hole-filled cross-section image 100T TEM three-dimensional image 100A Hole-filled three-dimensional image

Claims (1)

A method for evaluating the structure of catalyst carriers for fuel cells.
An untreated cross-sectional image acquisition step of acquiring a plurality of untreated cross-sectional images of the catalyst carrier, and
A hole-filled cross-sectional image creation step of creating a plurality of hole-filled cross-sectional images by filling the pore regions of the plurality of unprocessed cross-sectional images.
By laminating the plurality of untreated cross-sectional images and performing a process of constructing a three-dimensional image composed of elements that are structural units, the attribute of each element representing the filling portion inside the catalyst carrier is "1". To create an untreated three-dimensional image of the catalyst carrier, the attributes of each element representing the pores inside the catalyst carrier and the outer peripheral portion surrounding the catalyst carrier are set to "0". Dimensional image creation process and
By stacking the plurality of filled-in-filled cross-sectional images and performing a process of constructing a three-dimensional image composed of elements that are structural units, the attributes of each element representing the filled portion and the filled-in portion inside the catalyst carrier can be changed. A hole-filled three-dimensional image creation step for creating a hole-filled three-dimensional image of the catalyst carrier, which is set to "1" and the attribute of each element representing the outer peripheral portion surrounding the catalyst carrier is set to "0".
An exclusive OR (XOR) operation is performed between the attributes of each element of the unprocessed three-dimensional image and the attributes of each element of the filled-in three-dimensional image located at the same coordinates as the elements, and the exclusive OR is executed. Based on the result of the sum calculation, the first calculation step of extracting the element representing the pore among the elements of the unprocessed three-dimensional image, and
A NOR operation is performed on the attributes of each element of the unprocessed three-dimensional image and the attributes of each element of the filled-in-filled three-dimensional image located at the same coordinates as the elements. The second calculation step of extracting the element representing the outer peripheral portion from the elements of the unprocessed three-dimensional image based on the result of
In the untreated three-dimensional image, an entrance portion determination step of determining an element adjacent to an element representing the outer peripheral portion among the elements representing the pores as an element representing the entrance portion of the pores
By performing a breadth-first search of the element structure representing the pores included in the unprocessed three-dimensional image, the number and distance of through holes penetrating from the entrance portion of one of the pores to the other entrance portion are obtained. Through hole information acquisition process and
A method for evaluating the structure of a catalyst carrier for a fuel cell.

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