Manufacturing apparatus for battery electrode plates

Abstract

To provide an apparatus for manufacturing an electrode plate for a battery, which forms a battery with high volumetric efficiency.SOLUTION: An apparatus sets a pressure of applying a slurry 3 from a die 10 constant at the time of coating; has a position adjusting unit 19 which adjusts a space between the die 10 and a substrate 2 by adjusting a position of the die 10. When the apparatus forms each coating film, the position adjusting unit 19 adjusts the position of the die 10 so that a first space which is a space between the die 10 and the substrate 2, at the time when the apparatus forms a starting end portion 31 of the coating film, and a third space which is a space between the die 10 and the substrate 2, at the time when the apparatus forms an end portion 33 of the coating film, become larger than a second space which is a space between the die 10 and the substrate 2, at the time when the apparatus forms a portion between the starting end portion 31 and the end portion 33 of the coating film; and thereby the apparatus imparts roundness to the four corners of the coating film.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a manufacturing apparatus for a battery electrode plate for coating a slurry forming an active material layer on a current collector.

Background Art

[0002] Lithium-ion secondary batteries are widely used in applications such as drive power sources for electric vehicles and household storage batteries. In particular, all-solid-state lithium-ion secondary batteries have advantages such as a high energy density compared to conventional lithium-ion secondary batteries using an electrolyte solution. Therefore, it is possible to miniaturize the product compared to a lithium-ion secondary battery using an electrolyte solution, and in particular, the application of all-solid-state lithium-ion secondary batteries in the field of electric vehicles is desired.

[0003] Patent Document 1 describes the structure of a general all-solid-state battery. It has a form in which a positive electrode active material layer formed on the surface of a positive electrode current collector and a negative electrode active material layer formed on the surface of a negative electrode current collector sandwich a solid electrolyte layer, and for example, lithium ions are exchanged between the positive electrode and the negative electrode through the solid electrolyte layer, whereby charging and discharging in the all-solid-state battery are carried out. The positive electrode active material layer and the negative electrode active material layer on the positive electrode current collector and the negative electrode current collector are formed, for example, by coating a slurry forming each active material layer with a slit coater.

Prior Art Documents

Patent Documents

[0004] Patent Document 1: International Publication No. 2017-111133

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, as shown in the top view of FIG. 7(a) and the front view of FIG. 7(b), generally, the secondary battery 200 is commercialized by alternately laminating a positive electrode 201 and a negative electrode 202, which are square or rectangular electrodes, and packaging them with a frame portion 203. At this time, since the corner portions of the frame portion 203 have a certain curvature due to the molding process, it is more volume-efficient to package the electrodes with a curvature in their shapes when packaging the electrodes. That is, it is preferable that the active material layer of each electrode has a curvature according to the corner shape of the frame portion 203.

[0006] However, when forming an active material layer on a current collector by intermittently discharging a coating liquid while continuously conveying a web-shaped base material (current collector) using a slit die, basically, the four corners of the active material layer have a substantially right-angled shape. Therefore, there is a problem that in order to package the electrodes so as not to interfere with the frame portion 203, the electrode shape has to be made slightly smaller than the opening shape of the frame portion 203.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a manufacturing apparatus for an electrode plate for a battery that forms a battery with high volume efficiency.

Means for Solving the Problems

[0008] In order to solve the above problems, the manufacturing apparatus for a battery electrode plate of the present invention includes a die having a discharge port that is long in a direction intersecting the relative movement direction with a strip-shaped base material, intermittently applies slurry from the discharge port to the conveyed base material, and intermittently forms a substantially square coating film. The coating pressure of the slurry from the die during coating is set to be constant, and it has a position adjusting unit that adjusts the distance between the die and the base material by adjusting the position of the die. The first interval, which is the distance between the die and the base material when forming the start end portion of the coating film, and the third interval, which is the distance between the die and the base material when forming the end end portion of the coating film, in the formation of each coating film, are larger than the second interval, which is the distance between the die and the base material when forming the portion between the start end portion and the end end portion of the coating film. The position adjusting unit adjusts the position of the die so as to give roundness to the four corners of the coating film.

[0009] According to the manufacturing apparatus for the battery electrode plate described above, by giving roundness to the four corners of the coating film, the volume efficiency of the battery can be increased.

[0010] Also, it is preferable that the position adjusting unit changes the distance between the die and the base material from the first interval to the second interval at a predetermined acceleration and deceleration, and also changes the distance from the second interval to the third interval at a predetermined acceleration and deceleration.

[0011] By doing so, a coating film having roundness at the four corners can be formed relatively easily.

[0012] Also, it is preferable that the flow path of the slurry in the die has a shape that becomes narrower in the width direction of the die as it goes deeper from the discharge port in the vicinity of the discharge port.

[0013] By doing so, it becomes easy to make the widths of both end portions of the coating film smaller than the width of the portion between them in the base material conveyance direction, and a coating film having roundness at the four corners can be easily formed.

[0014] Further, the die preferably has a shim plate that defines the width of the slurry flow path in the width direction of the die, and the tip of the shim plate has a chamfer, so that the slurry flow path narrows in the width direction of the die as it goes deeper from the discharge port.

[0015] By doing so, it is possible to easily form a shape in which the slurry flow path narrows in the width direction of the die as it goes deeper from the discharge port.

[0016] Further, an on-off valve having an on-off valve for opening and closing the supply path of the slurry to the die is provided, and it is preferable to adjust the opening and closing time and the opening degree of the on-off valve according to the shape of the coating film at the start and stop of the slurry discharge.

[0017] By doing so, it becomes easy to make the width of both ends of the coating film smaller than the width of the portion between them in the substrate conveyance direction, and it is possible to easily form a coating film having rounded corners.

[0018] The movement of the die and the movement of the on-off valve by the position adjusting unit are preferably started at the same timing and completed at the same timing.

[0019] By doing so, the control of the coating operation can be facilitated.

[0020] Further, when the slurry discharged from the die particularly constitutes the active material layer of all-solid-state batteries, in order to stack a plurality of electrodes, the volume efficiency in the exterior can be increased by providing rounded corners.

Advantages of the Invention

[0021] According to the manufacturing apparatus for a battery electrode plate of the present invention, a battery with high volume efficiency can be formed.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0023] The coating apparatus, which is a manufacturing apparatus for an electrode plate for a battery according to the present invention, will be described with reference to the drawings.

[0024] FIG. 1 is a diagram for explaining the schematic configuration of a coating apparatus according to an embodiment of the present invention. The coating apparatus 1 is an apparatus for coating a slurry 3 on a substrate 2 fed by roll-to-roll. The slurry 3 is coated with a uniform thickness (uniform coating amount) along the feed direction MD of the substrate 2. Note that the width direction TD of the substrate 2 is a direction orthogonal to the feed direction MD of the substrate 2, and the Y-axis direction in FIG. 1 corresponds to this.

[0025] The substrate 2 in the present embodiment is a current collector in an all-solid-state battery. For example, the current collector for forming the positive electrode side is an aluminum foil, and the current collector for forming the negative electrode side is a copper foil, for example.

[0026] In addition, the slurry 3 in the present embodiment is an active material layer formed on a current collector, and is a fluid with relatively high viscosity containing an active material, a conductive assistant, a binder, and the like. The active material when forming the active material layer on the positive electrode side includes, for example, a composite oxide containing lithium and nickel. Further, the active material when forming the active material layer on the negative electrode side includes, for example, metals such as Si and Sn, or metal oxides such as TiO, Ti2O3, TiO2, or SiO2, SiO, SnO2.

[0027] The coating apparatus 1 includes a die 10 configured to be long along the width direction of the base material 2, and a supply means 20 for supplying the slurry 3 to the die 10. In the die 10, its longitudinal direction (Y-axis direction in FIG. 1) is referred to as the width direction TD, which is the same as the width direction TD of the base material 2. In this coating apparatus 1, a roller 5 facing the die 10 is installed, and the width direction TD of the die 10 and the direction of the rotation center line of the roller 5 are parallel. The base material 2 is guided by this roller 5, and the slurry 3 is coated in a state where the distance (gap) between the base material 2 and the discharge port 18 (the tip of the slit 12 described later) of the die 10 is adjusted to a predetermined value. Further, the distance (dimension d in FIG. 1) between the discharge port 18 and the base material 2 can be adjusted by a position adjustment portion 19 to which the die 10 is attached.

[0028] The die 10 is composed of a combined configuration in which a first divided body 13 having a first lip 13a with a tapered shape and a second divided body 14 having a second lip 14a with a tapered shape sandwich a shim plate 15 therebetween. Inside the die 10, a manifold 11 composed of a space long in the width direction TD (that is, the direction intersecting the relative movement direction between the base material 2 and the die 10) and a slit 12 connected to the manifold 11 are formed. Further, between the first lip 13a and the second lip 14a, a discharge port 18 which is the open end of the slit 12 is formed. That is, the manifold 11 and the discharge port 18 are connected via the slit 12.

[0029] The slit 12 is formed long in the width direction TD (i.e., the direction intersecting the relative movement direction of the base material 2 and the die 10) in the same manner as the manifold 11. The width dimension of the slit 12 is determined by the inner dimension of the shim plate 15, and a slurry 3 having a width dimension substantially the same as that of the slit 12 can be applied onto the base material 2. The gap dimension (height dimension) of the slit 12 is, for example, 0.4 to 1.5 mm. In this embodiment, the die 10 is installed in a posture where the gap direction of the slit 12 is the vertical direction and the width direction is the horizontal direction. That is, the die 10 is installed in a posture where the manifold 11 and the slit 12 are arranged side by side in the horizontal direction. Therefore, the direction in which the slurry 3 stored in the manifold 11 flows to the base material 2 through the slit 12 and the discharge port 18 is the horizontal direction.

[0030] Note that by changing the thickness of the shim plate 15, the pressure inside the manifold 11 (coating pressure) can be adjusted, and by this adjustment, it becomes possible to perform coating with a uniform film thickness on the slurry 3 having various characteristics.

[0031] Also, in this embodiment, the direction in which the slurry 3 flows to the base material 2 through the discharge port 18 is the horizontal direction, but it is not necessarily limited to this and can be appropriately changed. For example, it may be the upward direction or the downward direction, and can be set in any direction.

[0032] FIG. 3 shows the form of the shim plate 15 inside the die 10. The shim plate 15 has a substantially U-shaped configuration, and has a base portion 15a and two protruding portions 15b connected to both ends of the base portion 15a, and is arranged such that the protruding portions 15b face the discharge port 18 side (second lip side). By sandwiching this shim plate 15 between the first divided body 13 and the second divided body 14, a slit 12 which is a flow path of the slurry 3 from the manifold 11 toward the discharge port 18 is formed, and the width dimension of the slit 12 is defined by the interval between the inner sides of the two protruding portions 15b.

[0033] Further, a chamfered portion 15c is formed inside the tip of the protruding portion 15b which is the tip of the shim plate 15. By having this chamfered portion 15c, the slit 12 in the vicinity of the discharge port 18 has a shape that becomes narrower in the width direction TD of the die 10 as it goes deeper from the discharge port 18. In this embodiment, the dimension of the chamfered portion 15c is approximately 5 mm.

[0034] Returning to FIG. 1, an inflow portion 16 is provided at the central portion in the width direction TD of the die 10, and this inflow portion 16 consists of a through hole (inlet) that connects from the outside of the die 10 to the manifold 11. The supply means 20 includes a supply pipe 21 that supplies the slurry 3 toward this inflow portion 16, a tank 22 that stores the slurry 3, and a pump 23 for supplying the slurry 3 in this tank 22 to the die 10 through the pipe 21. From the above, the supply means 20 can supply the slurry 3 from the inflow portion 16 to the manifold 11. In this embodiment, as shown in FIG. 1, the inflow portion 16 is connected to the bottom portion 17 of the manifold 11, and is configured to allow the slurry 3 to flow in from this bottom portion 17.

[0035] And the manifold 11 can store the slurry 3 supplied from the supply means 20, and discharge the slurry 3 stored in the manifold 11 through the slit 12 from the discharge port 18 to the base material 2 that is sent roll-to-roll, and can continuously coat the base material 2 with the slurry 3. The gap dimension of the slit 12 is constant in its width direction, and the thickness of the slurry 3 applied onto the base material 2 is designed to be constant in the width direction. Also, although not shown, a filter for the slurry 3 is provided in the middle of the supply pipe 21.

[0036] The position adjustment unit 19 is a linear motion mechanism that connects the main body portion of the coating device 1 and the die 10, operates by a control device (not shown), and moves the die 10 in the direction of approaching and separating from the roller 5. By adjusting the position of the die 10 by this position adjustment unit 19, the distance between the discharge port 18 shown by the dimension d in FIG. 1 and the base material 2 is adjusted.

[0037] In addition, a supply control unit 40 is provided in the coating apparatus 1 midway through the supply path of the slurry 3 from the supply means 20 to the die 10, specifically, midway between the supply pipe 21 and the inflow portion 16.

[0038] The supply control unit 40 has a supply valve 41, and the operation of the supply valve 41 is controlled by a control device (not shown). Also, the inlet portion of the supply valve 41 is connected to the supply pipe 21 via the inlet portion of a return valve 51 described later, and the slurry 3 is supplied to the inlet portion of the supply valve 41. Further, the outlet portion of the supply valve 41 is connected to the die 10 via the supply pipe 21.

[0039] A valve body 42, which serves as an on-off valve for opening and closing the supply path of the slurry 3 from the supply means 20 to the die 10, is connected to an electric cylinder 43. When an electric signal is input to the electric cylinder 43, the valve body 42 moves. When the valve body 42 moves, two states of the supply valve 41 are switched and controlled: an open state in which a flow path for the slurry 3 is formed and a closed state in which the flow path for the slurry 3 is blocked. Also, the moving speed v1 of the valve body 42 is adjustable.

[0040] In addition, in the present embodiment, a return control unit 50 is provided between the supply control unit 40 and the supply means 20. The return control unit 50 is a means for returning the slurry 3 to the tank 22 when it is not necessary to supply the slurry 3 to the die 10 because the coating of the slurry 3 on the base material 2 is interrupted. The return control unit 50 has a return valve 51, and the operation of this return valve 51 is controlled by a control device (not shown). The inlet portion of the return valve 51 is connected to the supply pipe 21, and the outlet portion is connected to a return pipe 24 that leads to the tank 22.

[0041] The return valve 51 has a valve body 52 inside, and when the valve body 52 moves, the flow path inside the supply valve 51 is opened and closed. The valve body 52 is connected to an air cylinder 53, and the valve body 52 moves by the inflow and outflow of air to and from the air cylinder 53. By the movement of this valve body 52, the opening and closing of the return pipe 24 are switched and controlled.

[0042] Figure 1 shows a state where the slurry 3 is being applied to the substrate 2. In this state, the supply valve 41 is open and the return valve 51 is closed. As a result, the slurry 3 is supplied to the die 10 via the supply valve 41, and the slurry 3 is applied to the substrate 2 from the discharge port 18 of the die 10.

[0043] On the other hand, the return valve 51 is closed, and the flow path of the slurry 3 returning to the tank 22 via the return pipe 24 from the outlet of the return valve 51 is blocked. Therefore, all of the slurry 3 supplied by the pump 23 is supplied to the die 10.

[0044] In contrast to Figure 1, Figure 2 shows a state where the application of the slurry 3 is interrupted.

[0045] In this state, the supply valve 41 is closed and the return valve 51 is open. As a result, the flow path towards the die 10 is blocked, and all of the slurry 3 is returned to the tank 22 via the outlet of the return valve 51 and the return pipe 24.

[0046] A control valve 55 is provided in the middle of the return pipe 24, and the internal pressure of the slurry 3 in the return pipe 24 is adjusted by adjusting the flow path resistance in this control valve 55. This internal pressure is measured by a pressure gauge (not shown) provided in the return pipe 24. In this embodiment, the control valve 55 adjusts so that the internal pressure in the manifold 11 during application and the internal pressure of the slurry 3 in the return pipe 24 during interruption of application are substantially equal.

[0047] In this way, after the application of the slurry 3 is interrupted once, and then the slurry 3 is applied again as shown in Figure 1, a coating film of the slurry 3 is intermittently formed on the substrate 2.

[0048] Next, a side view showing how the slurry 3 is applied to the substrate 2 by the coating apparatus 1 of the present embodiment is shown in FIG. 4. Here, the substrate 2 is being conveyed at a constant conveyance speed v2, and in FIG. 4, for the sake of convenience, the substrate 2 is illustrated as being conveyed linearly. Also, the pressure of the slurry 3 supplied from the supply means 20 and applied from the die 10 is set to be constant.

[0049] FIG. 4(a) shows the start of formation of each coating film formed intermittently on the substrate 2. When the return valve 51 (see FIG. 1) changes from the open state to the closed state and at the same time the supply valve 41 changes from the closed state to the open state, the discharge of the slurry 3 from the die 10 starts. The location where the slurry 3 discharged from this die 10 comes into contact with the substrate 2 becomes the start end portion 31 of the coating film. Here, the distance between the die 10 and the substrate 2 at the start of discharge of the slurry 3 from the die 10 is dimension d1. In this description, the distance between the die 10 and the substrate 2 at this time is referred to as the first distance.

[0050] FIG. 4(b) shows a state where a predetermined time has elapsed since the start of formation of the coating film. Since the substrate 2 is conveyed at a constant conveyance speed v2 and the coating pressure of the slurry 3 from the die 10 is constant, a coating film with a uniform film thickness is formed on the substrate 2.

[0051] On the other hand, due to the operation of the position adjustment unit 19 (see FIG. 1), the distance between the die 10 and the substrate 2 is shortened from the dimension d1 at the start of coating film formation to the dimension d2. In this description, the distance between the die 10 and the substrate 2 at this time is referred to as the second distance.

[0052] FIG. 4(c) shows a state where a further predetermined time has elapsed from the time of FIG. 4(b). When forming the portion between the start end portion 31 and the end end portion 33 of the coating film, the distance between the die 10 and the substrate 2 is maintained at the dimension d2, and the formation of the coating film progresses. In the coating film, the portion where the distance between the die 10 and the substrate 2 is maintained at the dimension d2 and coated in this way is referred to as the stable coating portion 32.

[0053] Fig. 4(d) shows the completion of the formation of each coating film. When the return valve 51 (see Fig. 1) changes from the closed state to the open state and at the same time the supply valve 41 changes from the open state to the closed state, the discharge of the slurry 3 from the die 10 stops. As a result, the coating film on the substrate 2 and the die 10 are separated, and the end portion 33 of the coating film is formed.

[0054] On the other hand, until the supply of the slurry 3 stops as described above, due to the operation of the position adjusting unit 19 (see Fig. 1), the distance between the die 10 and the substrate 2 is expanded from the dimension d2 to the dimension d3. In this description, the distance between the die 10 and the substrate 2 at this time is referred to as the third interval.

[0055] Fig. 5 shows a diagram of the coating operation of the coating apparatus 1 of the present embodiment and the coating film obtained by this coating. Fig. 5(a) shows, in a diagram, the change in the distance between the coating film on the substrate 2 and the die 10 by the position adjusting unit 19 and the change in the state of the valve body 42 of the supply valve 41 by the electric cylinder 43 during the coating operation. Fig. 5(b) shows, in a top view, the shape of the coating film when the slurry 3 is coated according to the diagram of Fig. 5(a). Here, the conveyance speed v2 of the substrate 2 is about 1 m / min, and the coating pressure of the slurry 3 is set to be constant at a predetermined pressure (for example, 16 kPa) within the range of 15 - 20 kPa.

[0056] In the present embodiment, the dimension d1 which is the first interval and the dimension d3 which is the third interval for the distance between the die 10 and the substrate 2 are the same dimension. And while the supply valve 41 is in the closed state and the slurry 3 is not being discharged from the die 10, the distance between the die 10 and the substrate 2 is maintained at this dimension d1 (= d3).

[0057] Then, when starting to form the coating film, the movement of the valve body 42 of the supply valve 41 and the movement of the die 10 start at the same timing. Here, in the present embodiment, the die 10 and the valve body 42 move at a substantially constant speed except for predetermined acceleration and deceleration, and further startup and shutdown. The time required for the distance between the die 10 and the base material 2 to change from dimension d1 to dimension d2 is equal to the time required for the valve body 42 to change from the closed state to the open state, and the movement of the valve body 42 of the supply valve 41 and the movement of the die 10 are completed at the same timing. In the present embodiment, this time is set to 0.3 seconds. The predetermined acceleration and deceleration in this description refer to performing a common acceleration and deceleration operation in each intermittent coating.

[0058] Also, in the present embodiment, dimension d1 (= d3) is 200 μm, dimension d2 is 100 μm, and dimensions d1 and d3 are about twice that of dimension d2. Also, the moving speed v1 of the valve body 42 is set to 1 mm / s (60 mm / min), which is slower than the conveying speed v2 of the base material 2.

[0059] After the distance between the die 10 and the base material 2 becomes dimension d2 and the valve body 42 becomes open, this state is maintained for a predetermined time, and the stable coating portion 32 is formed.

[0060] Next, the die 10 and the valve body 42 start moving simultaneously, the distance between the die 10 and the base material 2 changes from dimension d2 to dimension d3, and the valve body 42 changes from the open state to the closed state. By completing this operation, the end portion 33 of the coating film is formed, and then an uncoated portion, which is the portion between the coating films, is formed until the valve body 42 moves. At this time, similar to the start of coating, the time required for the distance between the die 10 and the base material 2 to change from dimension d2 to dimension d3 is equal to the time required for the valve body 42 to change from the open state to the closed state, and the movement of the valve body 42 of the supply valve 41 and the movement of the die 10 are completed simultaneously. In the present embodiment, this time is set to 0.3 seconds. On the other hand, the time required for opening and closing the supply valve 41 is 0.3 seconds, while the time required for opening and closing the return valve 51 is 0.008 seconds, and the time required for opening and closing the supply valve 41 is much longer.

[0061] The shape of the coating film obtained by such a coating operation is shown in Fig. 5(b).

[0062] In forming the vicinity of the starting end portion 31 of the coating film, first, coating is started from a dimension d1 in which the distance between the die 10 and the base material 2 is larger than the dimension d2 at the time of forming the stable coating portion 32, and gradually narrowed to the dimension d2. Thus, the width w1 of the coating film at the start of coating is narrower than the width w2 of the coating film in the stable coating portion 32, and expands to the width w2 over time.

[0063] Also, in the present embodiment, at the same timing as the distance between the die 10 and the base material 2 is narrowed, the valve body 42 of the supply valve 41 gradually shifts from the closed state to the open state. Thereby, since the supply amount of the slurry 3 at the start of coating gradually increases, the width w1 of the starting end portion 31 becomes narrower compared to the case where the valve body 42 instantaneously shifts from the closed state to the open state.

[0064] Also, in the present embodiment, as shown in Fig. 3, since the inner side of the tip portion of the shim plate 15 has the chamfered portion 15c, the flow path of the slurry 3 in the die 10 has a shape that becomes narrower in the width direction of the die 10 as it goes from the discharge port 18 toward the back in the vicinity of the discharge port 18. Thereby, the width w1 of the starting end portion 31 becomes narrower compared to the case where it does not have the above shape.

[0065] As described above, by combining gradually changing the distance between the die 10 and the base material 2 when forming the vicinity of the starting end portion 31 of the coating film, gradually shifting the valve body 42 from the closed state to the open state, and having a shape in which the flow path of the slurry 3 in the die 10 becomes narrower in the width direction of the die 10 as it goes from the discharge port 18 toward the back in the vicinity of the discharge port 18, the width of the coating film gradually increases from the width w1 at the start of coating of the coating film to the width w2 in the vicinity of the starting end portion 31 of the coating film, and the shape of the corner portion of the coating film can be made rounded as shown in Fig. 5(b).

[0066] Also, when forming near the end portion 33 of the coating film, as the distance between the substrates 2 gradually expands from the dimension d2 at the time of forming the stable coating portion 32 to the dimension d3, the width of the coating film gradually narrows from the width w2 of the coating film in the stable coating portion 32 to the width w3.

[0067] Further, in the present embodiment, at the same timing as the distance between the die 10 and the substrate 2 expands, the valve body 42 of the supply valve 41 gradually shifts from the open state to the closed state. As a result, since the supply amount of the slurry 3 at the start of coating gradually decreases, the width w3 of the end portion 33 becomes even narrower compared to the case where the valve body 42 instantaneously shifts from the open state to the closed state.

[0068] Further, in the present embodiment, as shown in FIG. 3, since the inner side of the tip of the shim plate 15 has a chamfered portion 15c, the flow path of the slurry 3 in the die 10 has a shape that becomes narrower in the width direction of the die 10 as it goes from the discharge port 18 toward the back in the vicinity of the discharge port 18. As a result, the width w3 of the end portion 33 becomes even narrower compared to the case where it does not have the above shape.

[0069] As described above, by combining gradually changing the distance between the die 10 and the substrate 2 when forming near the end portion 33 of the coating film, gradually shifting the valve body 42 from the open state to the closed state, and having the flow path of the slurry 3 in the die 10 have a shape that becomes narrower in the width direction of the die 10 as it goes from the discharge port 18 toward the back in the vicinity of the discharge port 18, the width of the coating film gradually decreases from the width w2 of the stable coating portion to the width w3 near the end portion 33 of the coating film, and the shape of the corner portion of the coating film can be made rounded as shown in FIG. 5(b).

[0070] As described above, by gradually changing the distance between the die 10 and the substrate 2 when forming near the start portion 31 and the end portion 33 of the coating film, gradually shifting the valve body 42 from the closed state to the open state (from the open state to the closed state), and having the flow path of the slurry 3 in the die 10 have a shape that becomes narrower in the width direction of the die 10 as it goes from the discharge port 18 toward the back in the vicinity of the discharge port 18, it is possible to give roundness to the four corner portions of the substantially rectangular coating film.

[0071] On the other hand, rounding the four corners of the coating film as shown in FIG. 5(b) can also be achieved only by gradually changing the distance between the die 10 and the base material 2 when forming the vicinity of the start end portion 31 and the vicinity of the end end portion 33 of the coating film. In contrast, by further causing the valve body 42 to gradually shift from the closed state to the open state (from the open state to the closed state) as in the present embodiment and the flow path of the slurry 3 in the die 10 to have a shape that becomes narrower in the width direction of the die 10 as it goes from the discharge port 18 toward the back in the vicinity of the discharge port 18, the rounded shape of the four corner portions of the coating film can be controlled and a better shape can be obtained.

[0072] FIG. 6 is a schematic view showing a secondary battery structure using the coating apparatus of the present invention, FIG. 6(a) is a top view, and FIG. 6(b) is a front view.

[0073] The secondary battery 100 is a all-solid-state battery in the present embodiment. In the secondary battery 100, the positive electrode 101 and the negative electrode 102 are alternately laminated.

[0074] The positive electrode 101 is formed by coating a positive electrode active material layer on the surface of a positive electrode current collector by the coating apparatus 1 of the present invention, and the negative electrode 102 is formed by coating a negative electrode active material layer on the surface of a negative electrode current collector. A solid electrolyte layer 104 is provided between the positive electrode 101 and the negative electrode 102, and charging and discharging in the all-solid-state battery are carried out by, for example, the exchange of lithium ions between the positive electrode and the negative electrode through this solid electrolyte layer 104.

[0075] In such a secondary battery 100, after a plurality of cells (positive electrode 101, negative electrode 102, solid electrolyte layer 104) are laminated, it is externally packaged by a frame portion 103 for the purpose of blocking air and moisture and for the purpose of preventing short circuit.

[0076] This frame portion 103 is resin-molded to have an opening for housing the plurality of cells. Due to this molding process, generally, the corners of the opening have a rounded R shape. On the other hand, the four corners of the electrode manufactured by the coating process using a slit die generally have a shape with a small R and almost no roundness. When attempting to enclose this electrode with the frame portion 103, if the opening of the frame portion 103 and the electrode are substantially the same size, the shapes of the corners of both interfere. Therefore, conventionally, it was necessary to reduce the electrode size.

[0077] In contrast, in the present invention, it becomes possible to provide roundness to the corners of the electrode, and it becomes possible to house the electrode in a state where interference with the corners of the frame portion 103 is improved. As a result, it is possible to minimize the gap with the opening of the frame portion 103 and provide a battery with good volume efficiency. Further, in conventional batteries, since the gap between the frame portion and the electrode is large, the electrode may be damaged within the frame portion due to movement or the like. However, the present invention makes it possible to provide a highly safe battery.

[0078] With the above manufacturing apparatus for the battery electrode plate, it is possible to form a battery with high volume efficiency.

[0079] Here, the manufacturing apparatus for the battery electrode plate of the present invention is not limited to the illustrated form and may be of other forms within the scope of the present invention. For example, in the above description, the timing of the start of movement of the die 10 by the position adjustment unit 19 and the timing of the start of movement of the valve body 42 of the supply valve 41 are the same, and the timing of the completion of movement of the die 10 by the position adjustment unit 19 and the timing of the completion of movement of the valve body 42 of the supply valve 41 are the same. However, it is not limited to this, and an appropriate time difference may be provided so that the corners of the coating film have a better shape. The shape of the corners of the coating film may be adjusted by adjusting the opening and closing time and the opening degree of the valve body according to the shape of the coating film at the start and stop of the discharge of the slurry.

[0080] In the above description, the moving speed of the die 10 when changing the distance between the die 10 and the base material 2 is set to be constant, but it does not necessarily have to be constant, and the die 10 may move at a speed profile such that the corners of the coating film have a better shape.

[0081] Also, the distance d1 between the die 10 and the base material 2 at the start of the discharge of the slurry 3 and the distance d3 between the die 10 and the base material 2 at the completion of the discharge of the slurry 3 may be different.

[0082] Also, the chamfered portion 15c may not be provided on the shim plate 15, and the width of the flow path of the slurry 3 may be constant in the vicinity of the discharge port 18.

[0083] In the above description, a voice coil motor is used as the means for operating the shaft in the supply valve 41, but it is not limited to this, and for example, other linear motion mechanisms such as an air cylinder may be used.

[0084] Also, the base material may be in the form of a single sheet instead of a belt-shaped base material that is conveyed in a roll-to-roll manner. In that case, it may be in a form in which the die and the base material move relative to each other by moving the die with respect to the fixed base material.

[0085] Also, the manufacturing apparatus for the electrode plate for a battery of the present invention is not limited to the manufacture of all-solid-state batteries, and may be applied to, for example, lithium-ion batteries having an electrolytic solution instead of a solid electrolyte layer.

Explanation of Reference Numerals

[0086] 1 Coating apparatus (manufacturing apparatus for electrode plate for battery) 2 Base material 3 Slurry 5 Roller 10 Die 11 Manifold 12 Slit 13 First divided body 13a First lip 14 Second divided body 14a Second lip 15 Shim 15a Base part 15b Protruding part 15c Chamfered part 16 Inflow part 17 Bottom part 18 Discharge port 19 Position adjustment part 20 Supply means 21 Supply pipe 22 Tank 23 Pump 24 Return pipe 31 Starting end part 32 Stable coating part 33 Ending end part 40 Supply control part 41 Supply valve 42 Valve body 43 Electric cylinder 50 Return control part 51 Return valve 52 Valve body 53 Air cylinder 55 Control valve 100 Secondary battery 101 Positive electrode 102 Negative electrode 103 Frame part 104 Solid electrolyte layer 200 Secondary battery 201 Positive electrode 202 Negative electrode 203 Frame part

Claims

1. A manufacturing apparatus for a battery electrode plate, comprising a die having a discharge port that is long in a direction intersecting the relative movement direction with respect to a strip-shaped base material, intermittently applying a slurry from the discharge port to the conveyed base material to intermittently form a substantially square coating film, the coating pressure of the slurry from the die during coating is set to be constant, having a position adjusting unit that adjusts the distance between the die and the base material by adjusting the position of the die, comprising an on-off valve having an on-off valve that opens and closes the supply path of the slurry to the die, the first interval which is the distance between the die and the base material when forming the start end portion of the coating film and the third interval which is the distance between the die and the base material when forming the end end portion of the coating film in the formation of each coating film are larger than the second interval which is the distance between the die and the base material when forming the portion between the start end portion and the end end portion of the coating film, the position adjusting unit adjusts the position of the die, and according to the shape of the coating film at the start of the discharge of the slurry at the start end portion and at the stop of the discharge of the slurry at the end end portion, by adjusting the opening and closing time and the opening degree of the on-off valve, a manufacturing apparatus for a battery electrode plate, characterized in that the four corners of the coating film are rounded.

2. The position adjusting unit is characterized in that it changes the distance between the die and the base material from the first interval to the second interval at a predetermined acceleration and deceleration, and also changes the distance between the second interval and the third interval at a predetermined acceleration and deceleration. The manufacturing apparatus for a battery electrode plate according to Claim 1.

3. The slurry flow path in the die has a shape that narrows in the width direction of the die as it goes deeper from the discharge port in the vicinity of the discharge port. The manufacturing apparatus for a battery electrode plate according to Claim 1 or 2.

4. The die has a shim plate that defines the width of the slurry flow path in the width direction of the die, and the tip of the shim plate has a chamfer, thereby forming a slurry flow path shape that narrows in the width direction of the die as it goes deeper from the discharge port. The manufacturing apparatus for a battery electrode plate according to Claim 3.

5. The movement of the die and the movement of the on-off valve by the position adjusting unit start at the same timing and are completed at the same timing. The manufacturing apparatus for a battery electrode plate according to Claim 1.

6. The slurry discharged from the die is characterized by constituting an active material layer of an all-solid-state battery, and the manufacturing apparatus for a battery electrode plate according to any one of claims 1 to 5.

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