JP2008149332A - Male die, pressing method, and concentrating plate for concentrating spherical silicon solar cell manufactured using the pressing method - Google Patents

Abstract

The present invention relates to a male press die, a pressing method, and a pressing method capable of sharply forming a front end of a wall surface forming a boundary between concave portions when forming a plurality of adjacent concave portions on a workpiece. There is provided a concentrating plate for a concentrating spherical silicon solar cell manufactured using the same.
The present invention is a male press die for forming a plurality of adjacent recesses 31, which are formed in a polygonal column shape, and a plurality of punches 3 having a predetermined shape of a protrusion 7 at one end. And a base 7 that holds the plurality of punches 3 in a state in which the side surfaces are in close contact with each other, and fixes the protrusions 7 in a protruding state.
[Selection] Figure 5

Description

  The present invention relates to a male press mold for forming a plurality of adjacent recesses, a pressing method, and a concentrating plate for a concentrating spherical silicon solar cell manufactured by using this pressing method.

In recent years, various types of solar cells have been proposed. For example, Patent Documents 1 to 4 include solar cells in which a small solar cell element made of spherical silicon is arranged in each of a plurality of hemispherical recesses. It is disclosed. More specifically, in this form of solar cell (hereinafter referred to as a concentrating spherical silicon solar cell), the inner wall surface of the recess is used as a reflecting mirror and reflected from the inner wall surface as well as directly incident sunlight. The solar cell is configured to generate power by making it enter the solar cell element.
Japanese Patent Laid-Open No. 11-31837 JP 2002-50780 A JP 2002-164554 A JP 2005-317667 A

  By the way, in the concentrating spherical silicon solar cell as described above, how to increase the condensing rate from the inner wall surface of the recess becomes a problem. For this purpose, it is necessary to make the tip of the wall surface that forms the boundary between the adjacent recesses as sharp as possible. However, for example, in the solar cell described in Patent Document 4, since the recess is formed by cutting, there is a limit to sharply forming the boundary between the minute recesses from the viewpoint of dimensional accuracy in the cutting process. Yes, this has been a problem of improving the degree of light collection.

  Note that the above problems are not limited to the production of solar cells. When forming a plurality of recesses adjacent to a workpiece, the tip of the boundary between the recesses is sharpened in conventional cutting and the like. It was not possible to respond to such a request.

  The present invention has been made to solve the above problems, and when forming a plurality of adjacent recesses on a workpiece, the tip of a wall surface forming a boundary between the recesses can be sharply formed. It is an object of the present invention to provide a male press die, a press method, and a concentrating plate for a concentrating spherical silicon solar cell manufactured using the pressing method.

  The present invention has been made to solve the above-described problem, and is a male press mold that forms a plurality of adjacent recesses, and is formed in a polygonal column shape, and a convex portion having a predetermined shape is formed at one end. A plurality of formed punches, and a base for holding the plurality of punches in a state in which the side surfaces are in close contact with each other and fixing the protrusions in a protruding state.

  According to this configuration, the plurality of punches formed in a polygonal shape are held in a state where the side surfaces are in close contact with each other, so that the male die is formed. A simple gap can be easily formed. That is, in the cutting process as in the conventional example, there is a limit in creating a minute portion, and it is difficult to form a sharp boundary. Also in the case of press working, it was very difficult to sharply form a minute gap between punches when creating a male press die. On the other hand, in the present invention, the male mold is formed by preparing a plurality of punches having convex portions formed at one end and bundling them, instead of integrally forming the male mold. Therefore, it is possible to easily form a sharp gap at the back end between the convex portions of adjacent punches, and thereby form a wall surface having a sharp tip at the boundary between the recesses on the workpiece. be able to.

  The press-processed material produced using such a mold can be used for various applications, and can be used for, for example, a concentrating spherical silicon solar cell. In this case, one end of each punch is preferably formed in a hemispherical shape. A metal plate formed using this male press die can be formed with a plurality of recesses having sharp boundaries at the tip, and if a solar cell element is arranged in each recess, a concentrating spherical silicon A solar cell can be constructed. And in this solar cell, since the boundary of a recessed part is sharp, a condensing rate can be improved and the output of each battery element can be improved.

  The convex part of the punch is preferably mirror-finished. At this time, the center line average roughness on the surface of the convex portion of the punch is preferably 5 nm to 10 nm. By configuring the convex portion of each punch in this way, the roughness of the concave wall surface formed on the workpiece can be reduced. When such a wall surface is formed, particularly when a concentrating spherical silicon solar cell is formed, the concave wall surface becomes smooth, so that the light condensing degree can be further improved.

  Further, in the male press die, it is preferable that the cross-sectional shape of each punch is a regular hexagon, and a plurality of punches are arranged in a honeycomb shape in plan view on a base. By carrying out like this, many recessed parts can be efficiently arrange | positioned in the limited area in the workpiece. That is, the density of the formed recesses can be increased.

  Moreover, the pressing method according to the present invention is made to solve the above-described problem, and is formed in a polygonal column shape, a plurality of punches having a predetermined shape on one end, and the plurality of punches Preparing a male press die having a base for holding the punch in a state in which the side surfaces are in close contact with each other and fixing the protruding portion in a protruding state; and a plurality of recesses corresponding to the protruding portion of the punch And a step of arranging and pressing a metal plate between the male die and the female press die.

  The present invention has been made to solve the above-described problem, and is a concentrating spherical silicon solar cell concentrating plate manufactured by using the pressing method, wherein the convex portion of the punch is hemispherical. Is formed.

  As described above, according to the male press die and the pressing method according to the present invention, when forming a plurality of adjacent recesses on the workpiece, the front end of the wall surface forming the boundary between the recesses is sharply formed. can do.

  Hereinafter, an embodiment in which a male press die according to the present invention is applied to the production of a concentrating spherical silicon solar cell will be described with reference to the drawings. 1 is a perspective view of a male press die, FIG. 2 is a perspective view of a punch, and FIG. 3 is a plan view of FIG.

  First, the press die concerning this embodiment is explained. This press die is composed of a male press die and a female press die. As shown in FIG. 1, the male press die 1 supports a plurality of polygonal columnar punches 3 and supports them. The base 5 is comprised. As shown in FIG. 2, each punch 3 is formed in a polygonal column shape having a regular hexagonal cross section, and a hemispherical convex portion 7 is formed at one end. The plurality of punches 3 configured in this way are bundled so that the side surfaces are in close contact with each other. That is, as shown in FIG. 3, it arrange | positions so that planar view may become a honeycomb form. On the other hand, as shown in FIG. 1, the base 5 is formed in a rectangular parallelepiped shape, and has a hole corresponding to the shape of the bundled punches 3. A plurality of punches 3 are fixed to the base 5 by press-fitting the punches 3 bundled in the holes. At this time, one end of the punch 3, that is, the hemispherical surface 7 is projected from the surface of the base 5 by a predetermined length so as to function as a male mold. In addition, holes 9 are formed in the vicinity of each corner on the surface of the base, and adjustment pins 21 (see FIG. 5) for positioning with the female mold are disposed in the holes 9. That is, a similar hole is formed in the female die, and the adjustment pin can be inserted into both the male die and the female die, thereby positioning the both.

  Each punch 3 can be formed of various materials. For example, a cemented carbide having a hard layer of tungsten carbide having an average particle diameter of 1 μm or less can be used. As will be described later, since the concentrating spherical silicon solar cell needs to smooth the concave wall surface of the condensing plate in order to increase the condensing rate, the convex portion 7 at the tip of each punch 3 has a mirror surface. It is preferable that the roughness is set such that the center line average roughness is 5 nm to 10 nm, for example. Alternatively, the convex portion 7 can be lapped. Lapping is not particularly limited, and can be performed by a known method.

  FIG. 4 is a cross-sectional view of a female press die. As shown in the figure, the female press die 11 is formed in a rectangular parallelepiped shape, and a plurality of concave portions 13 corresponding to the hemispherical convex portions 7 of the male press die 1 are formed. As with the male press die 1, each recess 13 is arranged in a honeycomb shape. In addition, as described above, an adjustment pin hole 15 is formed at each corner of the surface of the female die 11.

  Next, a method for manufacturing a concentrating spherical silicon solar cell using the press mold will be described with reference to FIGS. FIG. 5 is a diagram showing a manufacturing process of the light collector, and FIG. 6 is an enlarged cross-sectional view of the concentrating spherical silicon solar cell.

  First, a light collector is manufactured. As shown in FIG. 5A, an aluminum metal plate B is placed between a male die and a female press die, and the press plate 1 and 11 are brought close to each other to press the metal plate B. Thus, as shown in FIG. 5B, the metal plate B is formed with a plurality of hemispherical concave portions 31 arranged in a honeycomb shape. Next, as shown in FIG. 5C and FIG. 5D, a through hole 32 is formed in the bottom surface of each recess 31 by a drill 41. At this time, since the interval between the recesses 31 is very narrow, if an attempt is made to simultaneously form the through holes 32 in the adjacent recesses 31, the adjacent drills 41 may interfere with each other. Therefore, every other drill 41 is disposed with respect to the recesses 31, and through holes 32 are formed in all the recesses 31 in two steps. When the through holes 31 are thus formed, the light collector B is completed.

  Subsequently, as shown in FIG. 6, the solar cell element 51 and the positive electrode 52 are arranged on the light collector B by a known method. That is, the solar cell element 51 made of silicon is disposed so as to close the through-hole 32 at the bottom of each recess 31, and the sheet-like positive electrode 52 sandwiched between the insulating sheets 53 and 54 on the lower surface of the light collector B is provided. It arrange | positions so that the positive electrode 52 may contact the solar cell element 51. FIG. The concentrating spherical silicon solar cell is completed through the above steps.

  As described above, according to this embodiment, instead of forming the male mold integrally, a plurality of polygonal punches 3 each having a convex portion 7 formed at one end thereof are prepared and bundled to form a base. A male press die is formed by fixing to the base 5. Therefore, as shown in FIG. 5 (a), between the convex portions 7 of the adjacent punches 3, it is possible to easily form a sharp gap S having a sharp rear end that was difficult in conventional cutting, As a result, as shown in FIG. 5B, the metal plate B can be formed with a wall surface 39 having a sharp tip at the boundary between the recesses 31. In particular, in the present embodiment, since the mold is used for manufacturing a concentrating spherical silicon solar cell, the concentrating plate B can be formed with a plurality of concave portions 31 having boundaries 55 with sharp tips. . As a result, it is possible to produce a solar cell that has a high light collection rate and can improve the output of each battery element.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, each punch is formed in a hexagonal cross section, but can be formed in other polygons, for example, a triangle, a quadrangle, etc., as long as the punches can be closely bundled and arranged.

  Moreover, in the said embodiment, although the press metal mold | die of this invention was applied to manufacture of a condensing type | mold spherical silicon solar cell, in addition to this, the processing target object which forms a wall surface with a sharp tip in the boundary between recessed parts It can be applied to all of the above. In this case, the shape of the end of each punch can be formed in a desired convex shape in addition to the hemispherical shape as described above. Even so, a wall having a sharp tip is formed at the boundary between the concave portions. can do.

  Next, examples of the present invention will be described. However, the present invention is not limited to the following examples.

  Below, the press metal mold | die for forming several recessed parts which consist of a regular hexagon whose one side is 1.28 mm in planar view was examined in the aluminum plate. As an example of the present invention, a male press die in which a plurality of punches as described above were bundled was formed. Further, as a comparative example, a male press die in which a convex portion and a base were integrally formed was prepared. Here, a male press die was integrally formed by electric discharge machining (Comparative Example 1), laser machining (Comparative Example 2), and cutting by a machining center (Comparative Example 3). The female press mold was also formed by the same processing method. However, the female press die in the examples was manufactured by cutting. Table 1 shows the curvature radius R1 of the back end portion of the gap between the male convex portions and the curvature radius R2 of the wall surface tip constituting the boundary between the female concave portions (FIGS. 7A and 7B). reference). Table 1 shows the results of measuring a plurality of locations of each mold with a tracer (Tokyo Seimitsu Co., Ltd., Conta Record 1600D).

表１に示すように、雄型プレス金型を一体成形した場合には、いずれの加工法であっても、曲率半径Ｒ１の微小化に限界があることが分かる。実施例については、雄型の凸部間の隙間が小さすぎ、コントレーサーの針（測定部）が挿入できなかったため、測定が不可能であった。但し、コントレーサーの針の先端部の曲率半径は、０．０２５ｍｍであるので、実施例におけるＲ１は、それよりも小さいと考えられる。そして、上記のようなプレス金型を用い、１６０トン油圧プレスによって、厚み０．２ｍｍのアルミニウム板（Ａ１０５０ＰＨ２４（ＪＩＳ規格））をプレス加工した。プレス速度は１０ｍｍ／ｓ、下死点停止時間は３秒とした。続いて、加工後のアルミニウム板における凹部間の境界先端の曲率半径Ｒ３（図７（ｃ）参照）を上記と同様に測定した。結果は、以下の通りである。

As shown in Table 1, when the male press die is integrally formed, it can be seen that there is a limit to miniaturization of the curvature radius R1 in any processing method. About the Example, since the clearance gap between male convex parts was too small, and the needle | hook (measurement part) of a tracer could not be inserted, measurement was impossible. However, since the radius of curvature of the tip of the needle of the tracer is 0.025 mm, R1 in the example is considered to be smaller than that. Then, an aluminum plate (A1050PH24 (JIS standard)) having a thickness of 0.2 mm was pressed by a 160-ton hydraulic press using a press die as described above. The pressing speed was 10 mm / s, and the bottom dead center stop time was 3 seconds. Subsequently, the curvature radius R3 (see FIG. 7C) of the boundary tip between the recesses in the processed aluminum plate was measured in the same manner as described above. The results are as follows.

表２に示すように、実施例によって作成された凹部間の境界先端の曲率半径が最も小さく、鋭くなっていることが分かる。また、上記結果から、曲率半径Ｒ３は、雄型に依存することが分かる。すなわち、実施例では、比較例３と同じ雌型を用いているにもかかわらず、曲率半径Ｒ３は、比較例３よりも遙かに小さく仕上がっており、凹部を形成する際には、雄型の精度が加工品の精度に大きく影響することが分かる。したがって、本実施例のような雄型プレス金型を形成しておけば、加工品における凹部間の境界先端を鋭く形成することができる。

As shown in Table 2, it can be seen that the radius of curvature of the boundary tip between the recesses created by the example is the smallest and sharp. Moreover, it turns out that the curvature radius R3 depends on a male type | mold from the said result. That is, in the example, although the same female mold as that of Comparative Example 3 is used, the radius of curvature R3 is finished to be much smaller than that of Comparative Example 3, and when forming the recess, the male mold is formed. It can be seen that the accuracy of the process greatly affects the accuracy of the processed product. Therefore, if the male press die as in this embodiment is formed, the boundary tip between the recesses in the processed product can be formed sharply.

It is a perspective view of a male press metallic mold. It is a perspective view of a punch. It is a top view of FIG. It is sectional drawing of a female type | mold press die. It is a figure which shows the manufacturing process of a light-condensing plate. It is an expanded sectional view of a concentrating spherical silicon solar cell. It is explanatory drawing of an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Male press die 3 Punch 5 Base 7 Convex part 11 Female press die 31 Concave part

Claims (7)

A male press mold that forms a plurality of adjacent recesses,
A plurality of punches that are formed in a polygonal column shape and have convex portions of a predetermined shape at one end,
A male press die comprising: a base for holding the plurality of punches in a state in which side surfaces are in close contact with each other and fixing the convex portions in a protruding state.   The male press die according to claim 1, wherein the convex portion of the punch is formed in a hemispherical shape.   The male press die according to claim 2, wherein the convex portion of the punch is mirror-finished.   The male press die according to claim 3, wherein the center line average roughness on the surface of the convex portion of the punch is 5 nm to 10 nm.   The male press die according to any one of claims 1 to 4, wherein a cross-sectional shape of the punch is a regular hexagon, and the plurality of punches are arranged in a honeycomb shape on the base in a plan view. A plurality of punches formed in a polygonal column shape and having a convex portion of a predetermined shape formed at one end thereof, and the plurality of punches are held in a state in which the side surfaces are in close contact with each other, and fixed in a state in which the convex portions protrude. Preparing a male press die having a base to be used;
Preparing a female press die having a plurality of concave portions corresponding to the convex portions of the punch;
And a step of placing and pressing a metal plate between the male die and the female die. A concentrating plate for a concentrating spherical silicon solar cell manufactured using the pressing method according to claim 6,
A condensing plate for a concentrating spherical silicon solar cell, wherein the convex portion of the punch is formed in a hemispherical shape.

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