JP6891850B2 - Die coating equipment - Google Patents

Description

The present invention relates to a die coating apparatus that supplies a coating material to a moving object to perform coating. More specifically, it relates to a die coating apparatus composed of two dies combined.

Conventionally, the formation of a coating film by die coating has been performed in various fields. For example, Patent Document 1 discloses a coating apparatus that performs multi-layer simultaneous coating by a die coater. In the apparatus of FIG. 1 of the same document, one slot die (13) is provided with a plurality of pockets (20 to 22) and their slots (23 to 25). As a result, the object (12) is coated with three layers in one coat.

Japanese Unexamined Patent Publication No. 2003-260400

However, the above-mentioned conventional technique has the following problems. There is a problem with the accuracy of the coating width. The document refers to the adjustment of the coating width by the "width control plate" ([0023] of the same document). However, since the coating material (“coating liquids 14, 15, 16” in the same document) is a fluid, it may spread in the width direction on the object after coming out of the slot die. Since this spread is difficult to be constant, the coating width may not be as intended.

The present invention has been made to solve the problems of the above-mentioned conventional techniques. That is, the problem is to provide a die coating device with improved accuracy of coating width.

The die coating apparatus according to one aspect of the present invention is an apparatus for coating an object with a coating material, and is a coating material between the first die and the first die combined with the first die. It has a second die that forms a slit-shaped discharge port, and a first shim and a second shim that are sandwiched between the first die and the second die to regulate the flow path of the discharge port. However, the first shim, which is the upstream side of the first shim and the second shim in the moving direction of the object, does not form a flow path in the central part in the longitudinal direction of the discharge port, and is bordered at both ends. The shape is such that the flow path is formed, and the second shim does not form a flow path in the region where the coating material is supplied by the edging flow path, but the coating material is supplied by the edging flow path. It has a shape that forms a main flow path in the central part, which is a non-existent area.

In the die coating apparatus according to the above aspect, the object is first coated in the edging flow paths at both ends in the width direction (longitudinal direction of the discharge port), and then coated in the main flow path in the central portion. .. As a result, both ends of the coating layer are first defined, and then the area between them is filled with the coating material. This improves the accuracy of the coating width. In addition, the coating of the edging portion and the coating of the central portion can be performed by passing the object through the die coating device once. The slit-shaped discharge port formed between the first die and the second die has a shape formed by sandwiching the first shim and the second shim between the first die and the second die. It shall mean that.

According to this configuration, a die coating device with improved coating width accuracy is provided.

It is a perspective view of the die coating apparatus which concerns on embodiment and the electrode plate coated by it. It is an exploded perspective view which shows the structure of the die coating apparatus which concerns on embodiment. It is a top view which shows the state in which the 1st die and the 1st shim are overlapped. It is a top view which shows the state in which the 1st die, the 1st shim, and the 2nd shim are overlapped. It is a front view which shows the die coating apparatus which concerns on embodiment as seen from the discharge port side. It is sectional drawing which shows the situation which the positive and negative electrode plates are laminated and pressed. (Comparative Example) It is sectional drawing of the situation corresponding to FIG. 6 when the accuracy of a coating width is low.

Hereinafter, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings. This embodiment embodies the present invention as a die coating apparatus 1 that performs the coating method shown in FIG. FIG. 1 shows a die coating device 1 and an electrode plate 2 which is a coated object that has been coated. The object of coating in this embodiment is the current collecting foil 3 which is the core material of the electrode plate 2. In the die coating device 1, the electrode mixture layer 4 is coated on the surface of the current collector foil 3. As a result, the electrode plate 2 is obtained.

The electrode mixture layer 4 formed by the die coating apparatus 1 has a edging portion 5 near both ends in the width direction and a central portion 6 between them. However, the edging portion 5 and the central portion 6 have the same composition, and there is no difference in the characteristics of the electrode reaction. The entire electrode mixture layer 4 is integrally involved in the charge / discharge function of the battery. The only difference between the edging portion 5 and the central portion 6 is that the timing of coating with the die coating apparatus 1 is slightly different. The electrode plate 2 coated by the die coating apparatus 1 is actually used after undergoing a drying process for removing the solvent component of the electrode mixture layer 4.

The die coating apparatus 1 will be described. The die coating device 1 is configured by superimposing the four members shown in FIG. The four members are the first die 7, the first shim 8, the second shim 9, and the second die 10 from the bottom in FIG. A concave manifold 11 is formed on the first die 7. Also in the second die 10, a concave portion similar to the manifold 11 is formed on the back surface which is not visible in FIG. 2. When the first die 7 and the second die 10 are combined as they are in the directions shown in FIG. 2, a hollow space formed by the manifold 11 is formed. This hollow space is a space containing a coating material to be used for coating.

In the actual die coating device 1, the first shim 8 and the second shim 9 are sandwiched between the first die 7 and the second die 10. The order of superposition is as shown in FIG. The first shim 8 and the second shim 9 are for forming a flow path between the first die 7 and the second die 10 for discharging the coating material in the manifold 11 for coating. .. The first shim 8 is formed with a penetrating portion 17 penetrating between the front and back surfaces, and two edging flow path portions 18 opening forward (downward to the left in FIG. 2) from the penetrating portion 17. The region between the two bordered flow path portions 18 is a central blocking portion 19 that does not form a flow path.

The second shim 9 is formed with a penetrating portion 21 penetrating between the front and back surfaces and a main flow path portion 24 opening forward from the penetrating portion 21. The main flow path portion 24 is formed at a position where it overlaps with the central blocking portion 19 in the first shim 8. The positions of both sides of the main flow path portion 24 in the second shim 9 are the side blocking portions 26 that do not form the flow path. The edging flow path portion 18 of the first shim 8 described above is formed at a position where it overlaps with the side blocking portion 26 of the second shim 9.

FIG. 3 shows a state in which the first die 7 and the first shim 8 of the above four members are overlapped. In FIG. 3, the first die 7 is only visible at the penetration portion 17 and the edging flow path portion 18 of the first shim 8. Of these, at the edging flow path portion 18, the portion of the manifold 11 of the first die 7 is visible.

FIG. 4 shows a state in which the second shim 9 is further superimposed on the state shown in FIG. In FIG. 4, the first die 7 (part of the manifold 11) is visible only at the penetration portion 21 in the second shim 9. The portion of the edging flow path portion 18 described above is covered with the side blocking portion 26 in the second shim 9 and is not visible. Further, at the location of the main flow path portion 24 in the second shim 9, the central blocking portion 19 in the first shim 8 is visible, but the first die 7 is not visible.

When the second die 10 is further superposed on the state shown in FIG. 4, the die coating apparatus 1 shown in FIG. 1 is obtained. The front surface of the die coating apparatus 1 in FIG. 1 is the surface of the second die 10 (the surface facing upward in FIG. 2). In addition, in FIGS. 3 and 4, the one located at the highest position in each state (first shim 8 in FIG. 3 and second shim 9 in FIG. 4) is shown with hatching.

FIG. 5 shows a view of the die coating device 1 as viewed from the discharge port side. FIG. 5 is a view of the die coating device 1 as viewed from the side of the electrode plate 2 in FIG. The flow direction (upper right → lower left in FIG. 1) of the current collector foil 3 (electrode plate 2) coated by the die coating device 1 is from the bottom to the top in FIG. In FIG. 5, hatching is added within the range in which the above four members exist.

As shown in FIG. 5, in the die coating apparatus 1, a slit-shaped discharge port is formed between the first die 7 and the second die 10 by the first shim 8 and the second shim 9. That is, the discharge port of the die coating device 1 is formed between the first die 7 and the second die 10 by the edging flow path portion 18 in the first shim 8 and the main flow path portion 24 in the second shim 9. It is a gap (a place where there is no hatching in FIG. 5).

The edging flow path portion 18 is a flow path of the coating material for forming the edging portion 5 in the electrode mixture layer 4 shown in FIG. The main flow path portion 24 is a flow path of the coating material for forming the central portion 6 of the electrode mixture layer 4. Therefore, with respect to the entire coating width in FIG. 5, the edging flow path portion 18 is located at both end portions, and the main flow path portion 24 is located between them, that is, in the central portion. There is almost no overlapping portion or gap between the edging flow path portion 18 and the main flow path portion 24. Further, when viewed in comparison with the flow direction of the current collector foil 3, the edging flow path portion 18 is located slightly upstream of the main flow path portion 24. Further, inside the die coating device 1, the manifolds 11 of both the first die 7 and the second die 10 are connected by the penetrating portions 17 and 21.

When coating is performed as shown in FIG. 1 with the die coating apparatus 1 configured as described above, the edging portions 5 near both ends in the width direction are first coated, and then the central portion 6 is coated. It will be. When the edging portion 5 is first coated, the coating material supplied from the edging flow path portion 18 onto the current collector foil 3 hardly spreads on the current collector foil 3. This is because the edging flow path portion 18 has a small dimension in the width direction (left-right direction in FIG. 5), and the supply amount of the coating material is limited. Then, even when the central portion 6 is coated immediately after that, the outer end portion of the edging portion 5 is not pushed outward. This is because the amount of the coating material supplied from the main flow path portion 24 is large to some extent, but the coating material is supplied only to the region between the edging portions 5 on both sides. Therefore, the stability of the entire width of the electrode mixture layer 4 shown in FIG. 1 is very high. Further, the coating of the edging portion 5 and the coating of the central portion 6 can be performed by one coating by the die coating device 1.

By coating the electrode plate with the die coating apparatus 1 in this way, there are the following advantages. In FIG. 6, the electrode mixture layer 4 (negative electrode), the separator layer 27, and the electrode mixture layer 28 (positive electrode) are all sequentially coated on the current collector foil 3 by the die coating device 1. It shows the situation of pressing in the thickness direction to increase the density after coating. Here, since the accuracy of the width of each coating layer is very high, it is possible to set the current collector foil 3 to have almost no uncoated portion as shown in FIG. This means that a short circuit between the electrode mixture layer 28 (positive electrode) and the current collector foil 3 is unlikely to occur. Further, the thickness of the pressed object shown in FIG. 6 is almost the same everywhere. Therefore, since the pressing pressure is evenly applied to the entire press object, cracking of the electrode mixture layers 4, 28 and the like during pressing is unlikely to occur.

If the width of each coating layer is not accurate, the position of the edge of the coating layer may shift. In that case, a short circuit may occur between the positive and negative electrodes due to the protrusion in the width direction. Further, in order to prevent this, it is conceivable to set the coating width to be smaller for the upper layer, but in that case, cracks may occur in the electrode mixture layers 4, 28 and the like during pressing. This is because if the thickness of the object to be pressed differs depending on the location due to the presence of the non-coated portion, the pressing pressure is applied unevenly. By using the die coating apparatus 1 of this embodiment, those harmful effects can be reduced.

As described in detail above, according to the die coating apparatus 1 according to the present embodiment, the coating of the edging portion 5 and the coating of the central portion 6 of the total width of the electrode mixture layer 4 are sequentially and 1 You can do it with a pass. As a result, the die coating apparatus 1 having high accuracy in the width direction is realized. In addition, the number of coatings can be reduced.

It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Therefore, as a matter of course, the present invention can be improved and modified in various ways without departing from the gist thereof. For example, the object to be coated is not limited to the electrode plate of the battery and may be anything. Even when the electrode plate of a battery is targeted, there are no particular restrictions on the type of battery or the polarity of the electrode plate.

1 Die coating device 7 1st die 8 1st shim 9 2nd shim 10 2nd die 18 Bordering flow path part 24 Main flow path part

Claims (1)

A die coating device that coats an object with a coating material.
1st die and
A second die that is combined with the first die to form a slit-shaped discharge port for discharging the coating material between the first die and the first die.
It has a first shim and a second shim that are overlapped and sandwiched between the first die and the second die to regulate the flow path of the discharge port.
The first shim, which is the upstream side of the first shim and the second shim in the moving direction of the object, does not form a flow path in the central portion in the longitudinal direction of the discharge port, and both end portions. It has a shape that constitutes a edging flow path.
The second shim does not form a flow path in the region where the coating material is supplied by the edging flow path, and is mainstream in the central portion which is a region where the coating material is not supplied by the edging flow path. A die coating device characterized by having a shape that constitutes a road.

Images