WO2018180790A1

WO2018180790A1 - Mold

Info

Publication number: WO2018180790A1
Application number: PCT/JP2018/011086
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: JP2018167352A

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, 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, and a cover layer which covers the surface of the projections and which is made from an alloy that has a hardness greater than that of the material of the projections, wherein the main material of the alloy is the same metal as the material of the projections.

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, when the through-hole is formed by bringing the protrusion of the mold into contact with the contacted object, the protrusion is worn due to the frictional force generated between the protrusion and the contacted object. In particular, the tip portion of the protrusion is heavily worn, and the accuracy of forming the through-hole with respect to the object deteriorates due to the wear of the protrusion. In addition, when the mold protrusion is 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.

The present invention has been made in view of such problems, and an object of the present invention is to provide a mold having excellent durability and capable of reducing the cost for forming a through hole.

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 integrally formed so as to protrude from the surface of the flat plate portion, and the same metal as the material of the protruding portion. And a coating layer that is made of an alloy having a higher hardness than the material of the protrusions and covers the surfaces of the plurality of protrusions.

According to the present invention, it is possible to provide a mold having excellent durability and capable of reducing the cost for forming a through hole.

It is a perspective view of the metal mold | die which concerns on an Example. It is a front view of the metal mold | die which concerns on an Example. It is the schematic which shows the use condition of the metal mold | die which concerns on an Example. It is an enlarged side view of the protrusion part of the metal mold | die which concerns on an Example. 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.

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 explaining the embodiments and the modifications schematically show the mold according to the present invention, and partial emphasis, enlargement, reduction, omission, etc. are performed in order to deepen understanding. In some cases, it does not accurately represent the scale or shape of each component. Furthermore, some of the numerical values used in the examples and the modifications are only examples, and can be variously changed as necessary.

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

Further, as shown in FIGS. 1 and 2, the mold 10 according to the present embodiment has a coating layer 20 laminated on the first surface 11 a of the flat plate portion 11. That is, the surfaces of the protrusions 12 and the receiving portions 13 of the mold 10 and other flat surfaces are covered with the covering layer 20.

As shown in FIG. 3, when forming a plurality of through holes in the metal foil 30 that is a workpiece, two molds 10 according to the present embodiment are prepared, and the two prepared molds 10 are used to form metal. The foil 30 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 30 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 protruding part 12 of one mold 10. 13 is formed. Then, by sandwiching the metal foil 30 between the two molds 10, the protrusion 12 and the metal foil 30 come into contact with each other, and a plurality of through holes are formed in the metal foil 30 at the same time. In FIG. 3, the covering layer 20 formed on the first surface 11 a of the flat plate portion 11 is omitted for convenience of explanation and illustration.

The processing object of the mold 10 according to the present embodiment is a metal foil 30 having a thickness of 5 to 40 μm. The metal foil 30 is used for a current collector foil of a secondary battery, for example. As the metal foil 30, for example, copper, aluminum, titanium, nickel (including these alloys), stainless steel, or the like is used.

The mold 10 (part other than the coating layer 20) is formed by applying a general electroforming technique to a mother mold made of a resin material on 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 present embodiment in consideration of the shape of the mold 10 and the like. In this embodiment, a material obtained by synthesizing nickel and cobalt at a desired mixing ratio is used as an electroforming material, and the mold 10 is formed from a 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 this shape, in this embodiment, when the metal foil 30 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 30 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 30 is formed by two molds 10. If a large number of through-holes are formed by sandwiching a plurality of times, the metal foil 30 is likely to be wrinkled and the result is easily broken. Further, if the positioning accuracy when the metal foil 30 is sandwiched between the molds 10 is low, the interval between the through holes formed in the metal foil 30 is different, and in some cases, adjacent through holes may communicate with each other. For this reason, in the present embodiment, the formation density of the protrusions 12 and the receiving portions 13 is set to 16 pieces / mm ² or more, so that the number of times that a certain region of the metal foil 30 is sandwiched between the two molds 10 is reduced. 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 arrangement | positioning relationship of the projection part 12 and the receiving part 13 are not limited to the content mentioned above, It can change suitably according to the quantity and formation location of the through-hole formed in the metal foil 30. FIG. 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 30 that is the workpiece. Here, although the height of the protrusion 12 is adjusted by the thickness of the metal foil 30, when the metal foil 30 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 setting in this way is that when the metal foil 30 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 electrolytic solution. It is because it becomes desirable to become a grade.

As shown in FIG. 4, 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. In FIG. 4, the coating layer 20 is omitted for convenience of illustration and description.

The protruding portion 12 a includes an inclined side surface 12 c that is inclined with respect to a direction orthogonal to the first surface 11 a of the flat plate portion 11. 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 may be 5 degrees or more (for example, 9 degrees). By setting the inclination angle θ as described above, the metal foil 30 is sandwiched between the two molds 10 and the through hole is formed, and then the two molds 10 are moved away from each other. The metal foil 30 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 30 having a thickness of 5 to 40 μm, the protrusion 12 that has broken the metal foil 30 is pulled out from the metal foil 30. The protrusion 12 is reduced from being caught by the metal foil 30. By reducing the catch of the protrusions 12, the metal foil 30 is prevented from being broken, and further, the frictional damage of the inclined side surface 12 c is prevented, leading to the improvement of the durability of the mold 10. become.

Further, the diameter 2r of the upper surface of the protruding portion 12a (that is, the diameter 2r of the top portion 12b) may be 50% or more of the thickness of the metal foil 30 that is the workpiece. That is, since the minimum thickness of the metal foil 30 in the present embodiment is 5 μm, the diameter 2r of the upper surface of the protruding portion 12a is 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 30 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.

By setting the diameter 2r of the upper surface of the projecting portion 12a, the tip of the projecting portion 12a (that is, the formation surface side of the top portion 12b) is prevented from being worn against the metal foil 30 having a thickness of 5 to 40 μm. Will be. In consideration of the accuracy for forming the protruding portion 12a (formation accuracy of the mother die), the surface area of the upper surface of the protruding portion 12a is more preferably 20 μm ² or more.

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 protruding portion 12 breaks through the metal foil 30, not only the force applied to the tip of the protruding portion 12 occurs in the extending direction of the protruding portion 12 (that is, the direction orthogonal to the first surface 11a), The force for extending the metal foil 30 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 when the metal foil 30 is processed, thereby preventing 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 30 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 present embodiment, the shape of the receiving portion 13 may be a cylindrical shape.

Furthermore, as shown in FIG. 5, the mold 10 according to the present embodiment has a coating layer 20 formed on the first surface 10a. That is, in the mold 10, the flat surface of the flat plate portion 11 (the non-formed surface of the protruding portion 12 and the receiving portion 13), the surface of the protruding portion 12 (the convex curved surface of the inclined side surface 12 c and the top portion 12 b), and the receiving portion 13. The surface of is protected by the coating layer 20. For example, the layer thickness of the coating layer 20 is several μm, but can be appropriately changed according to the material and thickness of the metal foil 30 and the material of the coating layer 20.

The covering layer 20 is made of an alloy having the same metal as the material of the flat plate portion 11 and the protruding portion 12 as a main material and having a higher hardness than the material of the flat plate portion 11 and the protruding portion 12. For example, when the flat plate part 11 and the protrusion part 12 are nickel cobalt alloys, you may form the coating layer 20 using a nickel boron (NiB) alloy as an alloy which has nickel as the main material. In this case, the coating layer 20 is formed on the first surface 11a by electroless plating.

By forming the coating layer 20 using the same metal as the material of the flat plate portion 11 and the projection portion 12 as a main material, an electroformed material (that is, the flat plate portion 11 and the projection portion 12) and a laminated material (that is, the coating layer 20). The coating layer 20 can be prevented from peeling off when the mold 10 is used. In addition, since the processed surface of the mold 10 itself is covered with the coating layer 20 made of a harder material, it is possible to prevent the protrusions 12 from being worn and to further improve the durability of the mold 10 itself. be able to.

An example of a method for manufacturing the mold 10 according to the present 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.

Subsequently, a general electroforming technique is applied to the mother mold on which the irregularities are formed, and the metal mold corresponding to the mother mold (that is, the state in which the flat plate portion 11, the projecting portion 12, and the receiving portion 13 are formed). Intermediate) is formed. Then, the mold is separated from the mother mold, electroless plating is performed on the surface of the mold (that is, the first surface 11a), and the coating layer 20 is laminated on the surface of the mold. Thereby, manufacture of the metal mold | die 10 is completed.

NiCo + NiB mold 10 is manufactured using nickel (Ni) and cobalt (Co) as the electroforming material, and nickel (Ni) and boron (B) as the laminated material. Durability experiments were conducted to form holes simultaneously.

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 in this example. As shown in Table 1, even after 1.2 million times of use, 98.6% before use was maintained, and no change in shape was observed.

<Modification>
In the above embodiment, the protrusion 12 is composed of the truncated cone-shaped protrusion 12a and the hemispherical apex 12b. However, the shape of the protrusion is not limited to this, 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 above embodiment is absent and only the protruding portion 12a is formed. Even in such a case, the inclination angle θ of the inclined side surface of the protrusion 32 may be set to 5 degrees or more, and the protrusion 32 is formed of the metal foil 30 with respect to the metal foil 30 having a thickness of 5 to 40 μm. It is possible to prevent the metal foil 30 from being broken and to improve the durability of the mold 10. Further, the surface area of the upper surface of the protruding portion 32 may be set to 20 μm ² or more, and the diameter 2r of the upper surface of the protruding portion 32 may be set to 50% or more of the thickness of the metal foil 30 as the workpiece. Wear of the tip of the protrusion 32 is prevented.

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 30 is not limited to the truncated cone, and may be various types of truncated pyramids. Even in such a case, the inclination angle θ of the inclined side surface of the protrusion 42 may be set to 5 degrees or more, and the protrusion 42 is formed of the metal foil 30 with respect to the metal foil 30 having a thickness of 5 to 40 μm. It is possible to prevent the metal foil 30 from being broken and to improve the durability of the mold 10. Further, the area of the upper surface of the protrusion 42 may be set to 20 μm ² or more, and this prevents the tip of the protrusion 42 from being worn. Further, 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

protrusions

42 and 52 can be dispersed during the processing of the metal foil 30, and wear of the

protrusions

42 and 52 can be further prevented. In the above-described embodiments and modifications, 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. However, a plurality of through holes may be simultaneously formed in the metal foil 30 using these two molds.

<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 projecting portions integrally formed so as to project from the surface of the flat plate portion, and the same metal as the material of the projecting portion as a main material; and And a coating layer made of an alloy having a higher hardness than the material of the protrusions and covering the surfaces of the plurality of protrusions.

Since the mold according to the first aspect is made of a metal having a hardness of HV650 or less, the overall thickness can be about 500 μm, and warpage is prevented. An opening is formed in the metal foil on the surface of the plurality of protrusions because a coating layer made of an alloy that is made of the same metal as the material of the protrusions and has a higher hardness than the material of the protrusions is formed. Therefore, the processed surface to be covered is covered with a harder material, so that wear of the protrusions 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 the second aspect of the present invention, in the first aspect 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 the third aspect of the present invention, in the first or second aspect of the present invention, the height of the protrusion 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 the fourth aspect of the present invention, in any one of the first to third aspects of the present invention described above, when the metal foil is sandwiched between two molds, 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 Mold 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 Covering layer 30 Metal foil

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;
A plurality of frustum-shaped projecting portions made of the same metal as the material of the flat plate portion and integrally formed so as to project from the surface of the flat plate portion,
A mold comprising: a metal having the same metal as the material of the protruding portion as a main material and made of an alloy having a higher hardness than the material of the protruding portion, and covering a surface of the plurality of protruding portions.
The mold according to claim 1, wherein the formation density of the protrusions on the surface of the flat plate portion is 16 pieces / mm 2 or more.
The mold according to claim 1 or 2, wherein the height of the protruding portion is 1.5 times or more the thickness of the metal foil.
4. A receiving portion that is depressed at a position facing the protruding portion of one mold when the metal foil is sandwiched between two molds is formed on the surface of the flat plate portion. The mold according to any one of the above.