WO2018180789A1

WO2018180789A1 - Mold

Info

Publication number: WO2018180789A1
Application number: PCT/JP2018/011085
Authority: WO
Inventors: 武史久津輪; 英二松本; 哲也山▲崎▼; 航志湯浅
Original assignee: 株式会社安永
Priority date: 2017-03-29
Filing date: 2018-03-20
Publication date: 2018-10-04
Also published as: JP2018167351A; CN110475651A; KR20190133234A

Abstract

This mold, for forming multiple through-holes in a 5-40μm thick metal foil, comprises a flat plate part formed from a metal with a hardness less than or equal to HV 650, and multiple frustum-shape projections made from the same metal as the material of the flat plate part and integrally formed so as to project from the surface of the flat plate part, wherein each of the multiple projections has an inclined side surface inclined no less than 5° to the direction orthogonal to the surface of the flat plate part, and the surface area of the top surface located at the tip is greater than or equal to 20 μm2.

Description

Mold

This invention relates to the metal mold | die for forming a through-hole with respect to the current collection foil used for electrodes, such as a secondary battery.

Conventionally, it is known that a large number of through holes are formed in a current collector foil used for an electrode of a secondary battery. For example, in Patent Document 1, a metal foil is sandwiched between a forming roll having a large number of fine protrusions formed on the surface and a receiving roll, and the two foils are rotated to pass between the two rolls. Through holes are formed.

On the other hand, as a general mold for forming a through-hole with respect to an object to be contacted, a mold having a substantially flat plate shape and having a plurality of protrusions (unevenness) formed on the surface thereof is also known. . For example, Patent Document 2 discloses a method for manufacturing a mold having a required concavo-convex pattern on the surface using a general electroforming technique.

Japanese Patent No. 5953597 JP 2013-142192 A

However, in the method for forming a through-hole using a roll-shaped mold, while applying a force in a direction different from the formation direction of the through-hole (that is, the thickness direction of the metal foil) after forming the through-hole in the metal foil Since the mold protrusion is pulled out from the metal foil, there is a problem that the metal foil is damaged and the protrusion is damaged due to the protrusion caught on the metal foil. With respect to this problem, by increasing the diameter of the roll, it is possible to reduce the catch on the metal foil, but this leads to an increase in the size of the mold itself. Moreover, when forming a through-hole in metal foil using a roll-shaped metal mold | die, it becomes difficult to form a through-hole with a pitch of 400 micrometers or less from the problem on the formation precision of the protrusion with respect to a roll main body.

On the other hand, in a general plate-shaped mold having a large number of irregularities formed on the surface, no force is applied in a direction different from the formation direction of the through hole after the through hole is formed in the metal foil. However, it is difficult to remove the metal foil from the mold only by moving the mold only in the thickness direction of the metal foil, and there is a risk that the metal foil may be damaged if force is applied to remove the mold from the metal foil. . In addition, it becomes difficult to pull out the metal foil from the mold, which leads to damage to the protrusions of the mold.

And, if the protrusions of the mold are worn, it is necessary to replace the mold itself, which increases the cost of the mold and the maintenance cost. For this reason, durability of a metal mold | die is strongly requested | required also in order to aim at the cost reduction of through-hole formation itself to metal foil.

This invention is made | formed in view of such a subject, The place made into the objective is provided with the outstanding durability, and the metal mold | die which can form a through-hole, preventing the failure | damage of metal foil. It is to provide.

In order to achieve the above-described object, the mold of the present invention is a mold for forming a plurality of through holes in a metal foil having a thickness of 5 to 40 μm, and is a flat plate portion made of a metal having a hardness of HV650 or less. And a plurality of frustum-shaped protrusions that are integrally formed so as to protrude from the surface of the flat plate portion, made of the same metal as the material of the flat plate portion, Each includes an inclined side surface inclined at least 5 degrees with respect to a direction orthogonal to the surface of the flat plate portion, and the surface area of the upper surface located at the tip is 20 μm ² or more.

According to the present invention, it is possible to provide a mold having excellent durability and capable of forming a through hole while preventing the metal foil from being damaged.

1 is a perspective view of a mold according to Example 1. FIG. 1 is a front view of a mold according to Example 1. FIG. FIG. 3 is a schematic view showing a usage state of a mold according to Example 1. It is an enlarged side view of the protrusion part of the metal mold | die which concerns on Example 1. FIG. FIG. 5 is an enlarged cross-sectional view of the mold along the line VV in FIG. 2. It is an expansion perspective view of the projection part of the metallic mold concerning a modification. It is an expansion perspective view of the projection part of the metallic mold concerning a modification. It is an expansion perspective view of the projection part of the metallic mold concerning a modification. It is an expanded sectional view of the metal mold | die which concerns on Example 2 shown similarly to FIG.

Hereinafter, the mold of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the content demonstrated below, In the range which does not change the summary, it can change arbitrarily and can implement. In addition, the drawings used for the description of each embodiment and modification schematically show the mold according to the present invention, and partial emphasis, enlargement, reduction, omission, etc. are made for better understanding. In some cases, it does not accurately represent the scale or shape of each component. Furthermore, some of the numerical values used in each embodiment and modification are examples, and can be variously changed as necessary.

<Example 1>
First, with reference to FIG. 1 thru | or FIG. 5, the metal mold | die which concerns on Example 1, and its use condition are demonstrated in detail. Here, FIG. 1 is a perspective view of the mold according to the first embodiment, and FIG. 2 is a front view of the mold according to the first embodiment. FIG. 3 is a schematic diagram illustrating a usage state of the mold according to the first embodiment. Further, FIG. 4 is an enlarged side view of the protrusion formed on the mold according to the first embodiment. FIG. 5 is an enlarged sectional view of the mold along the line VV in FIG.

As can be seen from FIGS. 1 and 2, the mold 10 according to the first embodiment includes a rectangular parallelepiped flat plate portion 11, a plurality of protrusions 12 formed on the first surface 11 a side of the flat plate portion 11, and the flat plate portion 11. It has the some receiving part 13 formed in the 1st surface 11a side. Here, the protruding portion 12 protrudes from the first surface 11a of the flat plate portion 11 and becomes a portion penetrating the workpiece. On the other hand, the receiving portion 13 is an opening that is recessed from the first surface 11 a of the flat plate portion 11. In the mold 10 according to the first embodiment, the second surface 11b of the flat plate portion 11 has a flat shape for attaching a jig for supporting the mold 10, but various jigs or Irregularities or the like may be formed to connect the support members.

As shown in FIG. 3, when forming a plurality of through holes in the metal foil 20 that is a workpiece, two molds 10 according to the first embodiment are prepared, and the two prepared molds 10 are used to form metal. The foil 20 is sandwiched. Accordingly, the receiving portion 13 of the other mold 10 is disposed at a position facing the protruding portion 12 of one mold 10. In other words, when the metal foil 20 is sandwiched between the two molds 10 on the first surface 11 a of the flat plate part 11, the receiving part is depressed at a position facing the protrusion 12 of one mold 10. 13 is formed. Then, by sandwiching the metal foil 20 between the two molds 10, the protrusion 12 and the metal foil 20 come into contact, and a plurality of through holes are formed in the metal foil 20 at the same time.

The object to be processed of the mold 10 according to Example 1 is a metal foil 20 having a thickness of 5 to 40 μm. The metal foil 20 is used, for example, as a current collector foil for a secondary battery. As the metal foil 20, for example, copper, aluminum, titanium, nickel (including these alloys), stainless steel, or the like is used.

The mold 10 is formed by applying a general electroforming technique to a mother mold made of a resin material in which irregularities corresponding to the protrusions 12 and the receiving portions 13 are formed. For this reason, the flat plate part 11 and the protrusion part 12 are integrally formed of the same metal. The mold 10 is formed of a metal having a hardness of HV650 or less in consideration of the thickness of about 500 μm from the viewpoint of strength and the warpage of the mold 10 itself. That is, a metal exceeding the hardness HV650 cannot be used as a constituent member of the mold 10 according to the first embodiment in consideration of the shape of the mold 10 and the like. In Example 1, what synthesize | combined nickel and cobalt by the desired mixing ratio is used as an electroforming material, and the metal mold | die 10 is formed from the nickel cobalt alloy (NiCo) of HV600 (nominal value). In addition, if the hardness of the metal mold | die 10 formed is HV650 or less, the said electroforming material uses other metals, such as nickel, copper, iron, or nickel molybdenum alloy (NiMo), alone or in mixture. Also good.

As shown in FIGS. 1 and 2, a total of 16 protrusions 12 are formed in a matrix (4 rows × 4 columns). Similarly, a total of 16 receiving portions 13 are formed in a matrix (4 rows × 4 columns). And the protrusion part 12 and the receiving part 13 are alternately arrange | positioned in one direction (longitudinal direction in FIG. 2). From such a shape, in Example 1, when the metal foil 20 is sandwiched between the two molds 10, a total of 32 through holes are formed simultaneously.

Here, the interval between the projecting portions 12 and the interval between the receiving portions 13 are preferably 250 μm or less, and more preferably 100 μm or less. That is, the formation density of the protrusions 12 and the receiving portions 13 is preferably 16 pieces / mm ² or more, and more preferably 100 pieces / mm ² or more. Here, when the metal foil 20 is used as a current collector foil of a secondary battery, it is desirable that more through holes are formed. However, a certain region of the metal foil 20 is formed by two molds 10. If a large number of through-holes are formed by sandwiching a plurality of times, the metal foil 20 is likely to be wrinkled and the result is that the reliability as a current collector foil is reduced. Further, if the positioning accuracy when the metal foil 20 is sandwiched between the molds 10 is low, the interval between the through holes formed in the metal foil 20 is different, and in some cases, the adjacent through holes may communicate with each other. For this reason, in Example 1, the number of times the fixed region of the metal foil 20 is sandwiched between the two molds 10 is set by setting the formation density of the protrusions 12 and the receiving portions 13 to 16 pieces / mm ² or more. While reducing, more through holes are formed at the same time so that the reliability as a current collector foil can be maintained.

In addition, the quantity and the arrangement relationship of the protrusion part 12 and the receiving part 13 are not limited to the content mentioned above, but can be suitably changed according to the quantity and formation location of the through-hole formed in the metal foil 20. For example, the protrusions 12 and the receiving portions 13 may be alternately arranged in the short side direction of FIG.

Furthermore, the height of the protrusion 12 is preferably 1.5 times or more, more preferably 2 to 3 times the thickness of the metal foil 20 that is the workpiece. Here, although the height of the protrusion 12 is adjusted by the thickness of the metal foil 20, when the metal foil 20 is used as a current collector foil of a secondary battery, the height of the protrusion 12 is set to 20 μm or more. Is particularly preferred. The reason for this setting is that when the metal foil 20 is used as a current collector foil of a secondary battery, the opening diameter of the through-hole formed in the current collector foil is 10 μm in order to smoothly pass the electrolyte. It is because it becomes desirable to become a grade.

As shown in FIGS. 4 and 5, the projecting portion 12 is composed of a projecting portion 12a located on the flat plate portion 11 side and a top portion 12b located at the tip of the projecting portion 12 and having a convex curved surface shape. The shape of the protrusion 12a is a truncated cone, and the shape of the top 12b is hemispherical.

The protruding portion 12a includes an inclined side surface 12c that is inclined by 5 degrees or more with respect to a direction orthogonal to the first surface 11a of the flat plate portion 11. In Example 1, the inclination angle (hereinafter also referred to as draft angle) θ of the inclined side surface 12c with respect to the direction orthogonal to the first surface 11a was set to 9 degrees. By setting such an inclination angle θ, the metal foil 20 is sandwiched between the two molds 10 and a through hole is formed, and then the two molds 10 are moved away from each other, so that the mold 10 The metal foil 20 can be easily removed. In other words, when the inclination angle of the inclined side surface 12c is set to 5 degrees or more with respect to the metal foil 20 having a thickness of 5 to 40 μm, the protrusion 12 that has broken the metal foil 20 is pulled out from the metal foil 20. The protrusion 12 is reduced from being caught by the metal foil 20. By reducing the catch of the protrusions 12, the metal foil 20 is prevented from being broken, and further, the frictional damage of the inclined side surface 12 c is prevented, leading to improvement in the durability of the mold 10. become.

In addition, the diameter 2r of the upper surface of the protrusion 12a (that is, the diameter 2r of the top 12b) is preferably 50% or more of the thickness of the metal foil 20 that is the workpiece. That is, since the minimum thickness of the metal foil 20 in Example 1 is 5 μm, the diameter 2r of the upper surface of the protruding portion 12a is preferably 2.5 μm or more. Here, the relationship between the diameter 2r of the upper surface of the protrusion 12a and the thickness of the metal foil 20 as the workpiece is synonymous with the surface area of the upper surface of the protrusion 12a being 5 μm ² or more. This is based on the result of calculating the minimum surface area of the upper surface of the protrusion 12a because the diameter 2r of the upper surface of the protrusion 12a is 2.5 μm or more.

However, in consideration of the accuracy for forming the protruding portion 12a (formation accuracy of the mother die), it is important that the surface area of the upper surface of the protruding portion 12a is 20 μm ² or more. Therefore, in Example 1, it is a necessary condition that the surface area of the upper surface of the protrusion 12a is 20 μm ² or more, and further, the diameter 2r of the upper surface of the protrusion 12a is 50% or more of the thickness of the metal foil 20. Is set to By setting the diameter 2r and the surface area of the upper surface of the protruding portion 12a, the tip of the protruding portion 12a (that is, the formation surface side of the top portion 12b) is worn against the metal foil 20 having a thickness of 5 to 40 μm. Will be prevented.

The top portion 12b is formed on the upper surface of the protruding portion 12a, but there is no step between the top portion 12b and the protruding portion 12a. That is, the convex curved surface of the top portion 12b is smoothly continuous with the inclined side surface 12c of the protruding portion 12a. Due to the shape of the top portion 12b, the diameter 2r of the top portion 12b is the same as the diameter 2r of the upper surface of the protruding portion 12a, and the top portion 12b is a hemisphere having a diameter of 2.5 μm or more. Here, when the protrusion 12 breaks through the metal foil 20, the force related to the tip of the protrusion 12 is not only generated in the extending direction of the protrusion 12 (that is, the direction orthogonal to the first surface 11a), The force for extending the metal foil 20 and the force for forming wrinkles act in a complicated manner, and force is also generated in the direction perpendicular to the extending direction of the protrusion 12. For this reason, the hemispherical top part 12b as described above is provided to disperse the stress applied to the tip of the projection part 12 during the processing of the metal foil 20 and prevent the projection part 12 from being worn.

As shown in FIG. 5, the shape of the opening that is the receiving portion 13 corresponds to the protruding portion 12, and is a shape constituted by a truncated cone portion and a hemispherical portion. However, the dimensions of the receiving portion 13 are generally larger than those of the protruding portion 12. This is to prevent the protrusions of other molds from coming into contact with the receiving portion 13 when the through hole is formed in the metal foil that is the workpiece. Due to the shape and dimensions of the receiving portion 13, even when the metal foil 20 is processed, the protruding portion 12 of one mold 10 does not contact the receiving portion 13 of the other mold 10, and the protruding portion 12. Can be prevented, and the life of the mold 10 itself can be improved.

Note that the shape of the receiving portion 13 is not limited to the above-described shape, and may be other shapes as long as the protruding portions of other molds can be prevented from contacting each other. For example, in the case of the first embodiment, the shape of the receiving portion 13 may be a cylindrical shape.

An example of a method for manufacturing the mold 10 according to the first embodiment will be described below. First, irregularities corresponding to the protrusions 12 and the receiving portions 13 are formed on the surface of the material by a known technique with respect to the material to be a matrix. As a method for forming the unevenness, for example, the material surface may be mechanical processing such as cutting, chemical processing such as etching, or laser irradiation. The unevenness needs to be processed with very high accuracy and fineness so that the various shapes and dimensions of the protrusion 12 and the receiving portion 13 described above can be realized. Thereafter, a general electroforming technique is applied to the mother mold on which the irregularities are formed, and the metal mold 10 corresponding to the mother mold is formed. Then, the mold 10 is completed by separating the mold 10 from the mother mold.

A nickel-cobalt alloy mold 10 was manufactured using nickel (Ni) and cobalt (Co) as electroforming materials, and a durability experiment was performed in which a plurality of through holes were simultaneously formed on a 15 μm aluminum foil. Here, the durability of the mold 10 was evaluated by comparing changes in the height and shape of the protrusion 12 before and after use. As shown in Table 1, even after 500,000 times of use, the height of the protrusion 12 is maintained at 96.3% before use, and since no change in shape is seen, it is very excellent. It was found to have durability.

<Modification>
In the first embodiment, the projecting portion 12 includes the truncated cone-shaped projecting portion 12a and the hemispherical top portion 12b. However, the shape of the projecting portion is not limited to this, and for example, FIG. 6 to FIG. The shape as shown in FIG. Here, FIGS. 6 to 8 are enlarged perspective views of the protrusions of the mold according to the modification.

As shown in FIG. 6, as a modification of the mold 10, a truncated cone-shaped protrusion 32 may be formed. That is, it is the same as that in which the top portion 12b in the first embodiment is absent and only the protruding portion 12a is formed. Even in such a case, if the inclination angle θ of the inclined side surface of the protrusion 32 is 5 degrees or more, the protrusion 32 is caught by the metal foil 20 with respect to the metal foil 20 having a thickness of 5 to 40 μm. Can be reduced, and the metal foil 20 can be prevented from being broken and the durability of the mold 10 can be improved. Further, the surface area of the upper surface of the protrusion 32 is set to 20 μm ² or more, and the diameter 2r of the upper surface of the protrusion 32 is set to 50% or more of the thickness of the metal foil 20 that is the workpiece, thereby causing the protrusion 32. This prevents wear of the tip of the metal.

As shown in FIG. 7, as another modification of the mold 10, a triangular frustum-shaped protrusion 42 may be formed. That is, the shape of the portion that breaks through the metal foil 20 is not limited to a truncated cone, and may be various types of truncated pyramids. Even in such a case, if the inclination angle θ of the inclined side surface of the protrusion 42 is 5 degrees or more, the protrusion 42 is caught by the metal foil 20 with respect to the metal foil 20 having a thickness of 5 to 40 μm. Can be reduced, and the metal foil 20 can be prevented from being broken and the durability of the mold 10 can be improved. Further, by setting the area of the upper surface of the protruding portion 42 to 20 μm ² or more, wear of the tip of the protruding portion 42 is prevented. Furthermore, when each of the plurality of protrusions 42 has a triangular frustum shape or other truncated pyramid shape, the protrusions 42 can be easily formed by linear machining.

Furthermore, as shown in FIG. 8, as another modified example of the mold 10, a protrusion 52 having a shape in which a side of the quadrangular pyramid is chamfered may be formed. By performing such a chamfering process, there is no pointed portion on the side surface of the projection 52, and wear of the projection 52 itself is prevented. That is, the durability of the mold 10 is further improved as compared with the protrusion 42 having corners as shown in FIG.

In addition, also in the modification shown in FIG.7 and FIG.8, you may provide the top part which makes a convex curve shape. Thereby, the stress applied to the tips of the

projections

42 and 52 can be dispersed during the processing of the metal foil 20, and wear of the

projections

42 and 52 can be further prevented. In the first embodiment and the modified example, the protrusion and the receiving part are formed on one mold, but only the protrusion is formed on one mold and only the receiving part is formed on the other mold. A plurality of through holes may be simultaneously formed in the metal foil 20 using these two molds.

<Example 2>
A mold 110 that is further improved in durability as compared with the mold 10 of the first embodiment will be described as a second embodiment with reference to FIG. Here, FIG. 9 is an enlarged cross-sectional view of the mold 110 according to the second embodiment, as shown in FIG.

As shown in FIG. 9, the mold 110 according to the second embodiment also has a rectangular parallelepiped flat plate portion 111 and a plurality of flat plates 111 formed on the first surface 111 a side, like the mold 10 according to the first embodiment. And a plurality of receiving portions 113 formed on the first surface 111 a side of the flat plate portion 111. Further, the second surface 111b of the flat plate portion 111 also has a flat shape in order to attach a jig for supporting the mold 110, similarly to the mold 10 according to the first embodiment.

Furthermore, as shown in FIG. 9, also in the mold 110 according to the second embodiment, the protruding portion 112 is positioned at the flat plate portion 111 side, the protruding portion 112 a and the tip of the protruding portion 112, and has a convex curved surface shape. The top part 112b is formed. And the shape of the protrusion part 112a is a truncated cone shape, and the shape of the top part 112b is hemispherical. From the above, the mold 110 according to the second embodiment and the mold 10 according to the first embodiment have the same shape and dimensions of the flat plate portion, the protruding portion, and the receiving portion. For this reason, description about the effect regarding these shapes and dimensions is omitted.

On the other hand, unlike the mold 10 according to the first embodiment, the mold 110 according to the second embodiment has a coating layer 130 formed on the first surface 110a. That is, in the mold 110, the flat surface of the flat plate portion 111 (the non-formation surface of the protruding portion 112 and the receiving portion 113), the surface of the protruding portion 112 (the convex curved surface of the inclined side surface 112c and the top portion 112b), and the receiving portion 113. The surface is protected by the coating layer 130. For example, the layer thickness of the coating layer 130 is several μm, but can be appropriately changed according to the material and thickness of the metal foil 20 and the material of the coating layer 130.

The covering layer 130 is made of an alloy having the same metal as the material of the flat plate portion 111 and the protruding portion 112 as a main material and having higher hardness than the material of the flat plate portion 111 and the protruding portion 112. For example, when the flat plate portion 111 and the protruding portion 112 are a nickel cobalt alloy, the coating layer 130 may be formed using a nickel boron (NiB) alloy as an alloy mainly composed of nickel. In this case, the coating layer 130 is formed on the first surface 111a by electroless plating.

By forming the coating layer 130 using the same metal as the material of the flat plate portion 111 and the protruding portion 112 as a main material, an electroformed material (that is, the flat plate portion 111 and the protruding portion 112) and a laminated material (that is, the covering layer 130). Can be improved, and peeling of the coating layer 130 during use of the mold 110 can be prevented. Further, since the processing surface of the mold 110 itself is covered with the coating layer 130 made of a harder material, it is possible to prevent the protrusion 112 from being worn, and to further improve the durability of the mold 110 itself. be able to.

NiCo + NiB mold 110 is manufactured by using nickel (Ni) and cobalt (Co) as electroforming materials and nickel (Ni) and boron (B) as laminated materials, and a plurality of through-holes for 15 μm aluminum foil Durability experiments were conducted to form holes simultaneously.

The durability of the mold 110 was evaluated by comparing changes in the height and shape of the protrusion 112 before and after use, as in Example 1. As shown in Table 2, even after 500,000 times of use, 99.7% before use is maintained, and since no change in shape is seen, it is even more than the mold 10 according to Example 1. It was found to have excellent durability.

<Aspect of the Present Invention>
A first aspect of the present invention is a mold for forming a plurality of through holes in a metal foil having a thickness of 5 to 40 μm, a flat plate portion made of a metal having a hardness of HV650 or less, and the flat plate portion A plurality of frustum-shaped protrusions made of the same metal as the material and integrally formed so as to protrude from the surface of the flat plate portion, and each of the plurality of protrusion portions is the flat plate portion The surface of the upper surface located at the tip is 20 μm ² or more.

Since the metal mold | die which concerns on a 1st aspect is formed from the metal of hardness HV650 or less, the thickness as a whole can be about 500 micrometers, and curvature is prevented. In addition, since the inclined side surface of the protruding portion is inclined at 5 degrees or more with respect to the direction orthogonal to the surface of the flat plate portion, when the protruding portion torn the metal foil having a thickness of 5 to 40 μm is pulled out from the metal foil, The protrusion is reduced from being caught by the metal foil, the metal foil is prevented from being broken, and the frictional damage of the inclined side surface is prevented, thereby improving the durability of the mold. Furthermore, since the surface area of the upper surface located at the tip of the protrusion is 20 μm ² or more, the formation of the protrusion becomes easy and wear of the tip of the protrusion due to contact with the metal foil is prevented. .

According to the second aspect of the present invention, in the first aspect of the present invention, each of the plurality of protrusions has a top portion having a convex curved surface formed at the tip thereof. Thereby, at the time of processing the metal foil, the top of the convex curved surface first comes into contact with the metal foil, the stress applied to the tip of the protruding portion at the time of processing the metal foil is dispersed, and the protruding portion is worn. Can be prevented.

According to the third aspect of the present invention, in the second aspect of the present invention, each of the plurality of protrusions has a truncated cone shape. Thereby, there is no pointed portion on the side surface of the protruding portion, the wear of the protruding portion itself is prevented, and the durability of the mold is improved.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the top portion has a hemispherical shape with a diameter of 50% or more of the thickness of the metal foil. As a result, when the metal foil is processed, the hemispherical top first comes into contact with the metal foil, and the stress applied to the tip of the protrusion at the time of processing the metal foil is dispersed, and the protrusion is worn. Can be prevented.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, each of the plurality of protrusions has a truncated pyramid shape. Thereby, a through-hole can be easily formed with respect to metal foil. In particular, when each of the plurality of protrusions has a triangular frustum shape or a quadrangular prism shape, the protrusions can be easily formed even by linear machining.

According to the sixth aspect of the present invention, in each of the first and second aspects of the present invention, each of the plurality of protrusions has a shape in which a side of the pyramid is chamfered. Thereby, there is no pointed portion on the side surface of the protruding portion, the wear of the protruding portion itself is prevented, and the durability of the mold is improved.

According to a seventh aspect of the present invention, in the first aspect of the present invention described above, the surface of the plurality of protrusions is mainly made of the same metal as the material of the protrusions, and the material of the protrusions. That is, a coating layer made of an alloy having a higher hardness is formed. As a result, the processed surface for forming the opening in the metal foil is covered with a harder material, wear of the protrusion can be prevented, and the durability of the mold itself can be further improved. . Moreover, the adhesiveness of a protrusion part and a coating layer can be improved, and peeling of the coating layer at the time of use of a metal mold | die can be prevented.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the formation density of the protrusions on the surface of the flat plate portion is 16 pieces / mm ² or more. . As a result, even when a large number of through holes are formed in a certain region of the metal foil, the number of times the mold contacts the certain region of the metal foil is reduced, and more The through holes are formed at the same time, and the reliability as the current collector foil of the secondary battery can be maintained.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the present invention, the height of the protruding portion is 1.5 times or more the thickness of the metal foil. Thereby, the opening diameter of the through hole formed for the metal foil having a thickness of 5 to 40 μm can be maintained at about 10 μm. When the metal foil is used as a current collector foil of a secondary battery, The electrolyte can be smoothly passed through the through hole, and the performance of the secondary battery can be improved.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects of the present invention described above, when the metal foil is sandwiched between two molds, with respect to the protruding portion of one mold. It is that the receiving part which was depressed in the position which opposes is formed. Accordingly, even when the through-hole is formed by sandwiching the metal foil between the two molds, the protrusion of one mold is prevented from contacting the other mold, and the protrusion of the mold Can prevent wear.

DESCRIPTION OF SYMBOLS 10 Metal mold | die 11 Flat part 11a 1st surface 11b 2nd surface 12 Protrusion part 12a Protrusion part 12b Top part 12c Inclined side surface 13 Receiving part 20 Metal foil 110 Mold 111 Flat plate part 111a 1st surface 111b 2nd surface 112 Protrusion part 112a Protrusion Portion 112b top portion 112c inclined side surface 113 receiving portion 130 coating layer

Claims

A mold for forming a plurality of through holes in a metal foil having a thickness of 5 to 40 μm,
A flat plate portion made of a metal having a hardness of HV650 or less;
Made of the same metal as the material of the flat plate portion, and having a plurality of frustum-shaped protrusions integrally formed so as to protrude from the surface of the flat plate portion,
Each of the plurality of projecting portions includes a tilted side surface that is tilted by 5 degrees or more with respect to a direction perpendicular to the surface of the flat plate portion, and the upper surface area located at the tip has a surface area of 20 μm 2 or more.
2. The mold according to claim 1, wherein each of the plurality of projecting portions is formed with a top portion having a convex curved surface at the tip.
The mold according to claim 2, wherein each of the plurality of protrusions has a truncated cone shape.
The mold according to claim 3, wherein the top portion has a hemispherical shape with a diameter of 50% or more of the thickness of the metal foil.
The mold according to claim 1 or 2, wherein each of the plurality of protrusions has a truncated pyramid shape.
The mold according to claim 1 or 2, wherein each of the plurality of protrusions has a shape in which a side of a pyramid is chamfered.
The coating layer which consists of an alloy which has as a main material the same metal as the material of the said protrusion part, and has hardness higher than the material of the said protrusion part is formed in the surface of these protrusion parts. Mold.
The mold according to any one of claims 1 to 7, wherein a density of the protrusions on the surface of the flat plate portion is 16 pieces / mm 2 or more.
The mold according to any one of claims 1 to 8, wherein a height of the protruding portion is 1.5 times or more a thickness of the metal foil.
10. A receiving portion is formed on the surface of the flat plate portion so as to be depressed at a position facing the protruding portion of one mold when the metal foil is sandwiched between two molds. The mold according to any one of the above.