Powder loading device

Abstract

The objective is to provide a powder placement device that can form a layer of powder having a predetermined dimension in the width direction on a predetermined surface of a substrate. [Solution] A powder placement device comprising: a transfer unit that holds powder and transfers a layer of the powder to a predetermined surface of a substrate; and a supply unit that, when transferring the powder from the transfer unit to the predetermined surface of the substrate, supplies and deposits the powder onto the transfer surface of the transfer unit, which sandwiches the powder between the transfer unit and the predetermined surface of the substrate, thereby forming a layer of the powder, wherein the transfer unit is formed such that a first dimension, which is the dimension of the transfer surface in the width direction of the substrate, is smaller than a second dimension, which is the dimension of the substrate in the width direction; the supply unit supplies the powder onto the transfer surface over an area larger than the first dimension, and deposits the powder over the entire width direction of the transfer surface, thereby forming a layer of the powder having the first dimension; and the transfer unit is configured to transfer the layer of powder having the first dimension from the transfer surface to the predetermined surface of the substrate.

Description

[Technical Field]

[0001] The present invention relates to a powder placing apparatus for forming a powder layer on a predetermined surface of a base material. [Background Art]

[0002] In the manufacturing process of a lithium-ion battery, an electrode sheet is formed by depositing electrode material powder on a predetermined surface of a sheet-shaped base material such as aluminum foil or copper foil conveyed in a roll-to-roll manner to form a powder layer, and then pressing and compressing the powder layer.

[0003] The powder placing apparatus used in such a manufacturing process of a lithium-ion battery comprises: a conveying mechanism that conveys the base material in a roll-to-roll manner; a supply section that supplies and deposits powder on a predetermined surface of the base material being conveyed to form a powder layer; and a pressing mechanism that presses the powder layer formed on the predetermined surface of the base material. An electrode sheet is formed by supplying powder from the supply section onto the predetermined surface of the base material conveyed by the conveying mechanism, and pressing the powder layer formed by depositing powder on the predetermined surface of the base material with the pressing mechanism. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent No. 6402200 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In an electrode sheet formed by the powder placing apparatus as described above, the electrode material layer (powder layer) is required to have a constant dimension on the predetermined surface of the base material in the width direction orthogonal to the conveying direction of the base material in the in-plane direction of the base material, for the purpose of stabilizing the performance of the lithium-ion battery and reducing the loss of electrode material. Therefore, an object of the present invention is to provide a powder placing apparatus capable of forming a powder layer having a predetermined dimension in the width direction on a predetermined surface of a base material. [Means for solving the problem]

[0006] The powder film forming apparatus of the present invention, which solves the above problems, comprises: a transfer unit that holds powder and transfers a layer of the powder to a predetermined surface of a substrate; and a supply unit that, when transferring the powder from the transfer unit to the predetermined surface of the substrate, supplies and deposits the powder onto the transfer surface of the transfer unit, which sandwiches the powder between the transfer unit and the predetermined surface of the substrate, thereby forming a layer of the powder. The transfer unit is formed such that a first dimension, which is the dimension of the transfer surface in the width direction of the substrate, is smaller than a second dimension, which is the dimension in the width direction of the substrate; the supply unit supplies the powder onto the transfer surface over an area larger than the first dimension, and deposits the powder over the entire width direction of the transfer surface, thereby forming a layer of the powder having the first dimension; and the transfer unit transfers the layer of the powder having the first dimension from the transfer surface to the predetermined surface of the substrate.

[0007] According to the above-described powder placement apparatus, the transfer section is formed such that the first dimension, which is the dimension of the transfer surface in the width direction of the substrate, is smaller than the second dimension, which is the dimension in the width direction of the substrate. The supply section supplies powder to the transfer surface over an area larger than the first dimension, and by supplying and depositing powder over the entire width direction of the transfer surface, a layer of powder having the first dimension is formed. The transfer section then transfers the layer of powder having the first dimension from the transfer surface to a predetermined surface of the substrate, thereby forming a layer of powder having the first dimension on the predetermined surface of the substrate. Therefore, a layer of powder having a predetermined dimension in the width direction can be formed on a predetermined surface of the substrate.

[0008] Furthermore, the transfer portion may be a strip-shaped sheet, and may be further equipped with a transfer roll that guides the transfer portion to a position where the powder is sandwiched between the predetermined surface and the transfer surface, and presses the transfer surface against the predetermined surface.

[0009] With this configuration, since the transfer portion is formed from a strip-shaped sheet, the processing of the transfer surface is easier compared to when a transfer roll is used as the transfer portion, that is, when a layer of powder is directly formed on the transfer roll and the layer of powder is transferred to a predetermined surface of the substrate. As a result, a transfer surface having a first dimension can be easily formed. This makes it easy to form a layer of powder having a predetermined dimension in the width direction on a predetermined surface of the substrate.

[0010] Furthermore, the powder may contain an adhesive, and the configuration may further include an auxiliary roll that sandwiches the substrate and the sheet between the transfer roll and the auxiliary roll, and a heating unit that heats the auxiliary roll.

[0011] With this configuration, by heating the auxiliary roll with the heating unit, the adhesive contained in the portion of the powder layer that is in contact with a predetermined surface of the substrate can be melted, thereby strengthening the adhesion between the predetermined surface of the substrate and the powder layer. As a result, the powder layer can be transferred to the predetermined surface of the substrate without leaving any residue on the transfer surface.

[0012] Furthermore, the configuration may also include a cooling unit for cooling the transfer roll.

[0013] With this configuration, cooling the transfer roll with the cooling unit suppresses the melting of the adhesive contained in the portion of the powder layer that comes into contact with the transfer surface, making it easier to peel the powder layer from the transfer surface. As a result, the powder layer can be transferred to a predetermined surface of the substrate without leaving any powder layer on the transfer surface.

[0014] Furthermore, the transfer portion may be configured as a temperature-sensitive adhesive sheet whose adhesive strength decreases as the temperature decreases.

[0015] With this configuration, since the transfer portion is a temperature-sensitive adhesive sheet whose adhesive strength decreases as the temperature drops, when the transfer portion is cooled by the cooling portion via the transfer roll, the powder layer becomes easier to peel off from the transfer portion. As a result, the powder layer can be transferred to a predetermined surface of the substrate without leaving a layer of powder on the transfer surface. [Effects of the Invention]

[0016] According to the powder placement apparatus of the present invention, a layer of powder having a predetermined dimension in the width direction can be formed on a predetermined surface of a substrate. [Brief explanation of the drawing]

[0017] [Figure 1] This figure shows a powder loading device according to one embodiment of the present invention. [Figure 2] This is a view from arrow A in Figure 1. [Modes for carrying out the invention]

[0018] The powder loading device in this embodiment will be described with reference to the drawings. In the following description, the three axes of the Cartesian coordinate system are X, Y, and Z, the horizontal direction is expressed as the X-axis direction and the Y-axis direction, and the direction perpendicular to the XY plane (i.e., the vertical direction) is expressed as the Z-axis direction.

[0019] Figure 1 shows a powder loading device 100 according to one embodiment of the present invention. Figure 2 is a view taken along arrow A in Figure 1.

[0020] As shown in Figure 1, the powder placement device 100 includes a first transport mechanism 2 for transporting a base material 1, a transfer unit 4 for holding powder 3 and transferring a layer of powder (hereinafter referred to as powder layer 31) to a predetermined surface of the base material 1 (hereinafter referred to as the transfer surface 11), a supply unit 5 for supplying and depositing powder 3 onto the transfer surface of the transfer unit 4 to form the powder layer 31, sandwiching the powder layer 31 between the transfer surface 11 and the transfer surface when transferring the powder layer 31 from the transfer unit 4 to the transfer surface 11, a squeegee unit 6 for leveling the powder layer 31 formed on the transfer surface to a predetermined thickness, and a second transport mechanism 7 having a transfer roll 71 that guides the transfer unit 4 to a position where the powder layer 31 is sandwiched between the transfer surface 11 and the transfer surface, and presses the transfer surface against the transfer surface 11.

[0021] Then, the powder 3 is supplied to the transfer surface by the supply unit 5 and deposited to form the powder layer 31, the formed powder layer 31 is leveled to a predetermined thickness by the squeegee unit, and the transfer unit 4 is guided by the transfer roll to a position where the powder layer 31 is sandwiched between the transfer target surface 11 of the base material 1 being conveyed by the first conveyance mechanism 2 and the transfer surface, and the transfer surface is pressed against the transfer target surface 11, thereby transferring the powder layer 31 from the transfer surface to the transfer target surface 11. Accordingly, the powder layer 31 is formed on the transfer target surface 11.

[0022] The base material 1 is a metal foil that serves as an electrode plate for a lithium-ion battery, and aluminum foil or the like is used when forming a positive electrode, and copper foil or the like is used when forming a negative electrode. The base material 1 is a strip-shaped sheet elongated in one direction, and is conveyed by the first conveyance mechanism 2.

[0023] The powder 3 is a powdery material in which at least a part of the surface of an electrode active material is coated with a non-aqueous binder. The powder 3 is supplied to the transfer surface by the supply unit 5 and deposited, thereby forming the powder layer 31. When the powder layer 31 formed on the transfer surface is transferred to the transfer target surface 11, the powder layer 31 is formed on the transfer target surface 11. Accordingly, a positive electrode or a negative electrode of a lithium-ion battery is formed.

[0024] The first conveyance mechanism 2 is for continuously conveying the base material 1 in the longitudinal direction thereof. The first conveyance mechanism 2 includes an unillustrated unwinding roll for unwinding the base material 1, an unillustrated winding roll for winding the base material 1, a plurality of unillustrated conveyance rolls through which the base material 1 unwound by the unwinding roll passes before being wound onto the winding roll, and an auxiliary roll 21 for guiding the base material 1 to a position where the powder layer 31 is transferred onto the transfer target surface 11. By rotating these rolls, the base material 1 is continuously conveyed. Further, the auxiliary roll 21 is provided so as to rotate about an axis parallel to the width direction (the Y-axis direction shown in FIG. 1) orthogonal to the conveyance direction of the base material 1 in the in-plane direction of the base material 1 as a rotation axis. In the following description, the width direction orthogonal to the conveyance direction of the base material 1 in the in-plane direction of the base material 1 is also referred to as the width direction in the description of the transfer unit 4 and the like.

[0025] The transfer section 4 has a powder layer 31 of electrode material formed on its transfer surface and is used to transfer the powder layer 31 to the transfer surface 11 of the substrate 1. In this embodiment, it is a long, strip-shaped sheet in one direction. The transfer section 4 is transported by the second transport mechanism 7, passing through the supply section 5, the squeegee section 6, and a position where the transfer section 4 is sandwiched between the auxiliary roll 21 and the transfer roll 71.

[0026] The supply unit 5 is for forming the powder layer 31 on the transfer surface 11 of the transfer unit 4, which sandwiches the powder layer 31 between the transfer surface 11 and the transfer surface 11 when transferring the powder layer 31 from the transfer unit 4 to the transfer surface 11. The supply unit 3 is formed to be long in the width direction and is positioned directly above the transfer surface at a predetermined distance from the transfer unit 4.

[0027] Furthermore, the supply unit 5 has a discharge port 51 for discharging the powder 3 and a storage unit connected to the discharge port 51 for accumulating the powder 3. The discharge port 51 is an opening for discharging the powder 3 and is formed to be long in the width direction. The storage unit is a space for accumulating the powder 3 formed within the supply unit 5 and is formed to be open at the lower end of the supply unit 5. The open end of this storage unit is the discharge port 51, and the powder 3 accumulated in the storage unit is discharged from the discharge port 51 by gravity. In this way, the powder 3 can be supplied and accumulated over the width direction on the transfer surface of the transfer unit 4, which is transported by the second transport mechanism 7, to form a powder layer 31. In this embodiment, the dimensions of the discharge port 51 and the storage unit in the width direction are equal.

[0028] The squeegee section 6 is for leveling the powder layer 3 formed on the transfer surface by the supply section 5 to a predetermined thickness, and is located downstream of the supply section 5 in the conveying direction of the transfer surface. In this embodiment, the squeegee section 6 is a roll having a rotation axis parallel to the width direction, and is positioned at a predetermined distance from the transfer section 4 so as to sandwich the transfer section 4 between the transfer roll 71. When the transfer section 4, which is conveyed by the second conveying mechanism 7, passes under the squeegee section 6, the powder layer 31 formed on the transfer section 4 comes into contact with the squeegee section 4, and the powder 31 contained in the powder layer 31 flows. As a result, the thickness of the powder layer 31 is leveled to a predetermined thickness.

[0029] The second conveying mechanism 7 is for conveying the transfer section 4 to a position where the powder layer 31 is sandwiched between the transfer surface 11 and the transfer surface. This second conveying mechanism 7 includes an unwinding roll (not shown) for unwinding the transfer section 4, a winding roll (not shown) for winding up the transfer section 4, a plurality of conveying rolls (not shown) through which the transfer section 4, unwinded by the unwinding roll, passes before being wound up by the winding roll, and a transfer roll 71 that guides the transfer section 4 to a position where the powder layer 31 is sandwiched between the transfer surface 11 and the transfer surface, and presses the transfer surface against the transfer surface 11. By rotating these rolls, the transfer section 4 is continuously conveyed to a position where the powder layer 31 is sandwiched between the transfer surface 11 and the transfer surface.

[0030] The transfer roll 71 is a roll that rotates with an axis parallel to the width direction as its axis of rotation, and is positioned at a predetermined distance from the auxiliary roll 21. The substrate 1, which is transported by the first transport mechanism 2, and the transfer section 71, which is transported by the second transport mechanism 7, pass between the auxiliary roll 21 and the transfer roll 71, thereby pressing the powder layer 31 formed on the transfer surface 71 against the transfer surface 11 and transferring it from the transfer surface 71 to the transfer surface 11. This allows the powder layer 31 to be formed on the transfer surface 11.

[0031] Furthermore, as shown in Figure 2, the transfer portion 4 in this embodiment is formed such that the first dimension s, which is the dimension of the transfer surface in the width direction, is smaller than the second dimension t, which is the dimension of the base material 1 in the width direction.

[0032] Here, the supply unit 5 supplies powder 3 to the transfer surface over an area larger than the first dimension s, ensuring that the powder 3 is supplied and deposited without any gaps across the entire width of the transfer surface. This forms a powder layer 31 having the first dimension s. Specifically, by making the dimensions of the discharge port 51 in the width direction larger than the first dimension s, the powder 3 is supplied to the transfer surface over an area larger than the first dimension s. Furthermore, the powder 3 supplied by the supply unit 5 to the area outside the transfer unit 4 falls, as shown in Figure 1. Note that the fallen powder 3 is not shown in Figure 2.

[0033] Then, the transfer unit 4 transfers the powder layer 31 having a first dimension s formed on the transfer surface from the transfer surface to the transfer surface 11. This makes it possible to form a powder layer 31 having a first dimension s on the transfer surface 11. Therefore, it is possible to form a powder layer 31 having a predetermined dimension in the width direction on the transfer surface 11.

[0034] Furthermore, the powder placement device 100 in this embodiment further includes a heating unit (not shown) for heating the auxiliary roll 21. The heating unit is a heater and is provided within the auxiliary roll unit 21. By heating the auxiliary roll 21 with this heating unit, the binder contained in the portion of the powder layer 31 that comes into contact with the transfer surface 11 can be melted, thereby strengthening the adhesion between the transfer surface 11 and the powder layer 31. As a result, the powder layer 31 can be transferred to the transfer surface 11 without leaving any residue on the transfer surface.

[0035] Furthermore, the powder placement device 100 in this embodiment further includes a cooling unit (not shown) for cooling the transfer roll 71. The cooling unit is a pipe that flows a refrigerant into the transfer roll 71 and is provided inside the transfer roll 71. By cooling the transfer roll 71 with this cooling unit, the melting of the binder contained in the portion of the powder layer 31 that is in contact with the transfer surface can be suppressed, making it easier to peel the powder layer 31 from the transfer surface. As a result, the powder layer 31 can be transferred to the transfer surface 11 without leaving any powder layer 31 on the transfer surface.

[0036] Furthermore, the transfer section 4 in this embodiment is a temperature-sensitive adhesive sheet that has the property of decreasing adhesive strength as the temperature decreases. Therefore, when the transfer section 4 is cooled by the cooling section via the transfer roll 71, the powder layer 31 becomes easier to peel off from the transfer section 4. As a result, the powder layer 31 can be transferred to the transfer surface 11 without leaving any powder layer 31 on the transfer surface 71.

[0037] As described above, with the powder placement device 100, the transfer unit 4 is formed such that the first dimension s, which is the dimension of the transfer surface in the width direction of the base material 1, is smaller than the second dimension t, which is the dimension of the base material 1 in the width direction. The supply unit 5 supplies powder 3 to the transfer surface over an area larger than the first dimension s, and by supplying and depositing powder 3 over the entire width direction of the transfer surface, a powder layer 31 having the first dimension s is formed. The transfer unit 4 then transfers the powder layer 31 having the first dimension s from the transfer surface to the transfer surface 11, so that a powder layer 31 having the first dimension s can be formed on the transfer surface 11. Therefore, a powder layer 31 having a predetermined dimension in the width direction can be formed on the transfer surface 11.

[0038] Furthermore, in the above embodiment, since the transfer portion 4 is formed from a strip-shaped sheet, compared to the case where the transfer roll 71 is used as the transfer portion 4, that is, when the powder layer 31 is directly formed on the transfer roll 71 and the powder layer 31 is transferred to the transfer surface 11, the processing of the transfer surface is easier, and a transfer surface having a first dimension s in the width direction can be easily formed. This makes it easy to form a powder layer 31 having a predetermined dimension in the width direction on the transfer surface 11.

[0039] Although embodiments of the present invention have been described in detail above with reference to the drawings, the configurations and combinations thereof in the above embodiments are merely examples, and additions, omissions, substitutions, and other modifications to the configurations are possible without departing from the spirit of the present invention. For example, in the above embodiments, an example in which the powder 3 includes a binder was described, but it does not have to be a binder as long as it is an adhesive that can bond the powders 3 together and the powders 3 together with the transfer surface 11.

[0040] Furthermore, although the above embodiment describes an example in which only one powder layer 31 is formed on the transfer surface 11, the invention is not limited to this, and multiple powder layers 31 may be formed on the transfer surface 11 in the width direction such that there is a certain gap between each powder layer 31 in the width direction. In this case, multiple transfer sections 41 are arranged in the width direction such that there is a certain gap between each of the transfer sections 4. Then, the supply section 5 forms a powder layer 31 on the transfer surface of each transfer section 4 and transfers the powder layer 31 from each transfer surface to the transfer surface 11. This makes it possible to form multiple powder layers 31 on the transfer surface 11 in the width direction such that there is a certain gap between each powder layer 31 in the width direction.

[0041] Furthermore, although the above embodiment describes an example in which the transfer section 4 is formed from a strip-shaped sheet, it may also be a transfer roll 71. In this case, the outer circumferential surface of the transfer roll 71 is used as the transfer surface, and the width dimension of the transfer surface is set to a first dimension s. Then, the supply section 5 supplies the powder 3 to the transfer surface of the transfer roll 71 and deposits it, thereby forming a powder layer 31 having the first dimension s on the transfer surface of the transfer roll 71, and transferring the powder layer 31 from the transfer surface of the transfer roll 71 to the surface to be transferred 11. This makes it possible to form a powder layer 31 having the first dimension on the surface to be transferred 11.

[0042] Furthermore, in the above embodiment, when transferring the powder layer 31 from the transfer section 4 to the transfer surface 11, the powder layer 31 is compressed by the auxiliary roll 21 and the transfer roll 71. However, a pair of press rolls may be provided downstream of the auxiliary roll 21 and the transfer roll 71 to further compress the powder layer 31. [Explanation of Symbols]

[0043] 100 Powder loading device 1 Base material 11 Transfer surface 2. First conveying mechanism 21 Auxiliary Roll 3 Powder 31 Powder layer 4 Transfer section 41 Transfer surface 5 Supply section 51 Discharge port 6. Squeegee section 7. Second Conveyor Mechanism 71 Transfer Roll s First dimension t Second dimension

Claims

1. A transfer unit that holds the powder and transfers a layer of the powder to a predetermined surface of the substrate, A powder placement apparatus comprising: a supply unit that, when transferring the powder from the transfer unit to the predetermined surface of the substrate, supplies and deposits the powder onto the transfer surface of the transfer unit, which sandwiches the powder between the predetermined surface of the substrate, thereby forming a layer of the powder; The transfer portion is formed such that the first dimension, which is the dimension of the transfer surface in the width direction of the substrate, is smaller than the second dimension, which is the dimension in the width direction of the substrate. The supply unit supplies the powder to the transfer surface over an area larger than the first dimension, and supplies and deposits the powder over the entire width direction of the transfer surface, thereby forming a layer of the powder having the first dimension. The powder placement apparatus is characterized in that the transfer unit transfers the powder layer having the first dimension from the transfer surface to the predetermined surface of the substrate.

2. The transfer portion is a strip-shaped sheet, The powder placement device according to claim 1, further comprising a transfer roll that guides the transfer portion to a position where the powder is sandwiched between the predetermined surface and the transfer surface, and presses the transfer surface against the predetermined surface.

3. The aforementioned powder contains an adhesive, An auxiliary roll that sandwiches the substrate and the sheet between the transfer roll, The powder loading apparatus according to claim 2, further comprising a heating unit for heating the auxiliary rolls.

4. The powder placement apparatus according to claim 2 or 3, further comprising a cooling unit for cooling the transfer roll.

5. The powder placement device according to claim 4, characterized in that the transfer portion is a temperature-sensitive adhesive sheet whose adhesive strength decreases as the temperature decreases.

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