Filtration device

Abstract

To provide a filtration device that filters electrode paste to be applied to an electrode foil using a cylindrical filter body and can extend the life of a filter.SOLUTION: A filtration device 10 includes: a bottomed cylindrical filter body 1 that filters out foreign matters from an electrode paste 3 formed by kneading components constituting an active material layer 92 of a battery electrode plate 9 into a paste form with a solvent 712; and a housing 2 that surrounds the filter body and has a paste outlet 221 that communicates with an opening 11K formed in an upper end 11 of the filter body, and a paste inlet 212 formed at a position opposite a lower end 12 of the filter body. The housing is formed so that a gap W (W1, W2) between a housing inner wall side surface 213 and a filter outer peripheral surface 131 of the filter body gradually widens from the upper end to the lower end of the filter body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a filtration device for filtering electrode paste. [Background technology]

[0002] Generally, when manufacturing a battery, the components that make up the active material layer of the electrode plate are mixed with a solvent to form a paste, and the electrode paste is applied to the surface of an electrode foil to produce the electrode plate. In applying this electrode paste, a filtering device is used to remove foreign matter from the electrode paste, as disclosed in Patent Documents 1 and 2, for example, which includes a cylindrical housing with an inlet at the bottom and an outlet at the top, and a cylindrical filter body within the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-101552 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-9233 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned filtration device, the electrode paste that flows into the housing through the inlet at the bottom of the housing penetrates into the filter primarily from the lower outer peripheral surface of the filter body closest to the inlet, which means that foreign matter contained in the electrode paste tends to adhere to the lower outer peripheral surface of the filter body as a gel-like semi-solid. In this case, the gap between the inner wall of the housing and the gel-like semi-solid adhering to the lower outer peripheral surface of the filter body narrows, increasing the paste pressure of the electrode paste that penetrates into the filter body on the inlet side, and therefore reducing the paste pressure of the electrode paste that penetrates into the filter body on the outlet side. As a result, the filter body needs to be replaced even though there is little gel-like semi-solid material, including foreign matter, adhering to the upper outer peripheral surface of the filter body, which shortens the filter body's original lifespan.

[0005] The disclosed technology has been made in consideration of such problems, and aims to provide a filtration device that can extend the filter life in a filtration device that filters electrode paste to be applied to electrode foil using a cylindrical filter body. [Means for solving the problem]

[0006] (1) One aspect of the disclosed technology for solving the above-mentioned problems is a filtration device comprising: a cylindrical filter body with a bottom that filters out foreign matter in an electrode paste obtained by kneading components that form an active material layer of an electrode plate of a battery into a paste form with a solvent; and a housing that surrounds the filter body and has a paste outlet that communicates with an opening formed at the upper end of the filter body and a paste inlet that is formed at a position opposite the lower end of the filter body, wherein the housing is formed so that the gap between the side of the inner wall of the housing and the outer filter surface of the filter body gradually widens from the upper end to the lower end of the filter body.

[0007] (2) In the filtering device described in (1), it is preferable that the gap between the housing inner wall side surface and the filter outer peripheral surface at the lower end of the filter body is larger than the gap between the housing inner wall side surface and the filter outer peripheral surface at the upper end of the filter body by at least the maximum thickness of the deposits adhering to the lower outer peripheral surface of the filter.

[0008] (3) In the filtering device described in (1) or (2), the housing preferably includes a guide portion that guides the electrode paste flowing in from the paste inlet toward the side of the housing inner wall, and the guide portion preferably has a protrusion that protrudes tapered toward the paste inlet, and a cover portion that is connected to the base end of the protrusion and covers the lower end of the filter body.

[0009] (4) In the filtering device described in any one of (1) to (3), it is preferable that the housing is provided with a heating device for heating the electrode paste flowing along the side of the inner wall of the housing.

[0010] (5) In the filtering device described in any one of (1) to (4), it is preferable to provide a pressure gauge that measures the paste pressure of the electrode paste flowing through the paste inlet and the paste outlet, and to provide a filter replacement control unit that outputs a replacement signal for the filter body when the pressure difference of the paste pressure measured by the pressure gauge is greater than a reference value. [Brief explanation of the drawings]

[0011] [Figure 1] 1A to 1C are process overview diagrams illustrating a method for manufacturing an electrode assembly including a paste filtering step using a filtering device according to one aspect of the present embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the filtration device shown in FIG. [Figure 3] 3 is a block diagram of a filter replacement control unit in the filtering device shown in FIG. 2. FIG. [Figure 4]3 is a schematic cross-sectional view showing the state of deposits adhering to the outer peripheral surface of the filter immediately after the start of use of the filter in the filtering device shown in FIG. 2.

[0023] FIG. [Figure 5] 3 is a schematic cross-sectional view showing the state of deposits adhering to the outer peripheral surface of the filter in the filtering device shown in FIG. 2 when the filter needs to be replaced. FIG. [Figure 6] FIG. 10 is a schematic cross-sectional view showing the state of deposits adhering to the outer peripheral surface of the filter immediately after the start of use of the filter in the filtering device of the comparative example. [Figure 7] 10 is a schematic cross-sectional view showing the state of deposits adhering to the outer peripheral surface of a filter when the filter needs to be replaced in a filtering device of a comparative example. FIG. [Figure 8] FIG. 3 is a schematic cross-sectional view of a first modification of the filtering device shown in FIG. [Figure 9] FIG. 3 is a schematic cross-sectional view of a second modification of the filtering device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Explanation of this filtration device> Next, a filtration device according to one aspect of an embodiment of the above-disclosed technology (hereinafter referred to as "the filtration device") will be described in detail with reference to the drawings, after explaining an outline of a method for manufacturing an electrode plate including a paste filtration process using the filtration device, and comparing it with a comparative filtration device.

[0013] (Electrode body manufacturing method) FIG. 1 shows a process overview diagram illustrating a method for manufacturing an electrode plate, including a paste filtering step using a filtering device according to one aspect of the present embodiment. FIG. 2 shows a schematic cross-sectional view of the filtering device shown in FIG. 1. Here, the X direction indicates the longitudinal direction of the electrode plate in the paste application step, the Y direction indicates the vertical direction of the electrode plate in the same step, and the Z direction indicates the short-side direction (width direction) of the electrode plate in the same step. As shown in FIGS. 1 and 2, the method for manufacturing an electrode plate 9, including a paste filtering step S2 using this filtering device 10, includes a paste kneading step S1, a paste filtering step S2, a paste application step S3, a drying step S4, and a winding step S5. The electrode plate 9 is formed by coating an active material layer 92 on a strip-shaped electrode foil 91.

[0014] The electrode plate 9 may be either a positive electrode plate or a negative electrode plate, but here, the positive electrode plate of a lithium ion secondary battery will be described as an example. The electrode foil 91 of this positive electrode plate is a metal foil extending in a strip shape in the longitudinal direction (X direction), and is preferably made of aluminum or an aluminum alloy. The thickness of the electrode foil 91 is, for example, about 5 μm to 20 μm. The active material layer 92 is made of, for example, a lithium transition metal oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 It consists of an active material such as acetylene black (acetylene black), a conductive material such as acetylene black, and a binder such as polyvinylidene fluoride (PVdF).

[0015] In the paste kneading step S1, for example, powder 711 consisting of the active material, conductive material, thickener, etc. that constitute the active material layer 92 is fed into a twin-screw kneader 71, and then a solvent 712, a binder 713, etc. are further fed and kneaded to produce a paste-like electrode paste 3. The positive electrode paste 3 has an NV (Non-volatile Organic Compound) value of, for example, about 70 to 80%, and a viscosity of, for example, about 3000 to 8000 mPa·s. The electrode paste 3 produced in the paste kneading step S1 is fed to the filtration device 10 via a feed pump PP and a feed pipe 72.

[0016] In the paste filtering step S2, foreign matter in the electrode paste 3 kneaded into a paste form is filtered using a filtering device 10 including a cylindrical filter body 1 with a bottom and a housing 2 surrounding the filter body 1 and having a paste outlet 221 communicating with an opening 11K formed in the upper end 11 of the filter body 1 and a paste inlet 212 formed in a position opposite the lower end 12 of the filter body 1. The filtered electrode paste 3 is stored in a storage tank 74 via a feed pump PP and a feed pipe 73.

[0017] In the paste application process S3, electrode paste 3 is supplied from storage tank 74 via supply pump PP and supply pipe 75, and is applied to strip-shaped electrode foil 91 supplied from rewinding device 81 using die coater 76 or the like. The electrode paste 3 applied to electrode foil 91 forms an active material layer 92. The thickness of active material layer 92 is, for example, approximately 50 μm to 200 μm. In the drying process S4, the electrode foil 91 coated with active material layer 92 is passed through a drying booth 84, during which the solvent contained in the active material layer 92 is volatilized, thereby adhering the active material layer 92 to the electrode foil 91. In addition, in the winding process S5, the electrode plate 9, in which the active material layer 92 is adhered to the electrode foil 91, is wound into a coil by winding device 82. Note that the paste application process S3, drying process S4, and winding process S5 are each provided with a plurality of auxiliary rollers 83 for guiding the movement of electrode foil 91.

[0018] (Details of this filtration device) Next, the present filtration device 10 will be described in detail. Fig. 3 shows a block diagram of the filter replacement control unit in the filtration device shown in Fig. 2. Fig. 4 shows a schematic cross-sectional view of the filtration device shown in Fig. 2, illustrating the state of deposits on the outer peripheral surface of the filter immediately after the filter begins to be used. Fig. 5 shows a schematic cross-sectional view of the filtration device shown in Fig. 2, illustrating the state of deposits on the outer peripheral surface of the filter when it is time to replace the filter.

[0019] 1 to 5, this filtering device 10 includes a cylindrical filter body 1 with a bottom that filters out foreign matter in electrode paste 3, which is made by kneading components that form active material layers 92 of battery electrode plates 9 into a paste with a solvent 712, and a housing 2 that surrounds the filter body 1 and has a paste outlet 221 that communicates with an opening 11K formed in an upper end 11 of the filter body 1, and a paste inlet 212 formed in a position opposite the lower end 12 of the filter body 1. The housing 2 also includes a housing main body 21 that houses the filter body 1, and an upper lid 22 that detachably seals an upper end opening 211 of the housing main body 21.

[0020] The filter body 1 includes an upper end portion 11 detachably connected to the upper lid 22 of the housing 2, a cylindrical filter layer 13 formed by laminating resin fibers such as polyethylene or polypropylene in a nonwoven fabric form, a cylindrical paste flow path 14 surrounded by the filter layer 13, and a resin lid (lower end portion) 12 that seals the paste flow path 14 at the lower end of the filter layer 13. The resin lid (lower end portion) 12 may be the filter layer 13. The paste flow path 14 is formed with the same diameter as the opening 11K formed in the upper end portion 11 of the filter body 1. The mesh size of the filter layer 13 is, for example, approximately 40 to 60 μm. Because gel-like semi-solid matter (also referred to as "adherent matter"; the same applies hereinafter) 4 containing foreign matter adheres to the filter outer peripheral surface 131 and the lower end portion 12 of the filter body 1, the filter body 1 may become clogged during the paste filtration step S2. In such a case, the filter body 1 must be replaced.

[0021] To detect when to replace the filter body 1, the filtering device 10 is preferably provided with pressure gauges Z1 and Z2 that measure the paste pressure P (P0, P4) of the electrode paste 3 flowing through the paste inlet 212 and the paste outlet 221, and a filter replacement control unit 77 that outputs a command to replace the filter body 1 when the pressure difference (P0 - P4 = △P) of the paste pressure P measured by the pressure gauges Z1 and Z2 is greater than a reference value △PK. By comparing the pressure difference (P0 - P4 = △P) between the paste pressures P (P0, P4) at the paste inlet 212 and the paste outlet 221 with the reference value, the optimal time to replace the filter can be determined, further extending the life of the filter body 1.

[0022] The filter replacement control unit 77 includes an input unit 771 that inputs the paste pressure P (P0, P4) measured by the pressure gauges Z1 and Z2, a memory unit 773 that stores a reference value △PK of the pressure difference of the paste pressure P (P0, P4) at the time of replacement of the filter body 1, a calculation unit 772 that compares the pressure difference △P of the paste pressure P (P0, P4) measured by the pressure gauges Z1 and Z2 and input to the input unit 771 with the reference value △PK of the pressure difference stored in the memory unit 773, and a filter replacement display unit 774 that outputs a replacement signal for the filter body 1 when the pressure difference (P0-P4=△P) of the paste pressure P (P0, P4) of the pressure gauges Z1 and Z2 compared and calculated by the calculation unit 772 is greater than the reference value △PK of the memory unit 773.

[0023] Furthermore, the housing 2 of the present filtering device 10 is formed so that the gap W (W1, W2) between the housing inner wall side surface 213 and the filter outer peripheral surface 131 of the filter body 1 gradually widens from the upper end 11 to the lower end 12 of the filter body 1. Here, the housing inner wall side surface 213 is linearly inclined, but this is not necessarily limited to this, and it may be curvedly inclined, for example.

[0024] In this case, the electrode paste 3 flowing into the housing 2 through the paste inlet 212 is separated into a housing-side paste laminar flow 31 that moves along the housing inner wall side surface 213 toward the upper end 11 of the filter body 1, and a filter-side paste laminar flow 32 that approaches the filter outer peripheral surface 131 and permeates into the filter layer 13. Therefore, as shown in FIG. 4, the electrode paste 3 is supplied to the upper end 11 of the filter body 1 by the housing-side paste laminar flow 31. Therefore, in the electrode paste 3 in the housing 2, the paste pressure P2 on the upper end 11 side of the filter body 1 is relatively less likely to decrease than the paste pressure P1 on the lower end 12 side of the filter body 1. As a result, as shown in FIG. 5, the filter body 1 can be used until the gel-like semi-solid material 4J adhering to the upper outer peripheral surface 13J of the filter body 1 increases to the same extent as the gel-like semi-solid material 4K adhering to the lower outer peripheral surface 13K of the filter body 1.

[0025] 5, even if a step occurs at the boundary KK between the upper end of the gel-like semi-solid material 4J adhering to the upper outer peripheral surface 13J of the filter body 1 and the filter upper outer peripheral surface 13J, causing a pressure loss in which the paste pressure P2 is partially reduced, the gap W between the housing inner wall side surface 213 and the filter outer peripheral surface 131 gradually narrows, and the paste pressure P11 from the housing inner wall side surface 213 increases. Therefore, the paste pressure P necessary for the electrode paste 3 to penetrate into the filter layer 13 can be ensured even at the upper outer peripheral surface 13J of the filter body 1. As a result, the filtering ability of the entire filter is improved, and the life of the filter body 1 can be extended to its original life.

[0026] Furthermore, it is preferable that the gap W2 between the housing inner wall side surface 213 at the lower end 12 of the filter body 1 and the filter outer peripheral surface 131 of the filter body 1 is larger than the gap W1 between the housing inner wall side surface 213 at the upper end 11 of the filter body 1 and the filter outer peripheral surface 131 of the filter body 1 by at least the maximum thickness T of the gel-like semi-solid material 4K adhering to the filter lower outer peripheral surface 13K.

[0027] In this case, regardless of the state of the gel-like semi-solid material 4 adhering to the filter outer peripheral surface 131, the housing-side paste laminar flow 31 flowing along the housing inner wall side surface 213 is maintained, and a larger amount of electrode paste 3 is stably supplied to the upper end portion 11 of the filter body 1. As a result, the filter body 1 can be used more stably until the gel-like semi-solid material 4J adhering to the upper outer peripheral surface 13J of the filter body 1 increases to the same extent as the gel-like semi-solid material 4K adhering to the lower outer peripheral surface 13K of the filter body 1.

[0028] The gap W2 between the housing inner wall side surface 213 at the lower end 12 of the filter body 1 and the filter outer peripheral surface 131 of the filter body 1 may be 1.05 times or more, or may be 1.1 times or more, the gap W1 between the housing inner wall side surface 213 at the upper end 11 of the filter body 1 and the filter outer peripheral surface 131 of the filter body 1. This makes it possible to maintain a wide path for supplying the electrode paste 3 to the upper end 11 of the filter body 1 even when a gel-like semi-solid material 4K adheres to the outer peripheral surface 131 of the lower end 12 of the filter body 1. Furthermore, if the gap W2 is too wide compared to the gap W1, the paste pressure P in the housing 2 may be too low, making it difficult for the electrode paste 3 to penetrate into the filter layer 13. Therefore, for example, the gap W2 may be 1.25 times or less, or may be 1.15 times or less, the gap W1.

[0029] Furthermore, it is preferable that the gap X between the lower end portion 12 of the filter body 1 and the housing inner wall bottom surface 213S is formed to be approximately the same as the gap W2 between the housing inner wall side surface 213 at the lower end portion 12 of the filter body 1 and the filter outer peripheral surface 131 of the filter body 1.

[0030] In this case, the electrode paste 3 flowing into the housing 2 from the paste inlet 212 tends to form a housing-side paste laminar flow 31 that moves continuously in a laminar state from the housing inner wall bottom surface 213S side to the housing inner wall side surface 213 side. Therefore, the paste pressure P2 of the electrode paste 3 on the upper end 11 side of the filter body 1 in the housing 2 is less likely to decrease than the paste pressure P1 on the lower end 12 side of the filter body 1. As a result, as shown in Fig. 5, the filter body 1 can be used until the gel-like semi-solid material 4J adhering to the upper outer peripheral surface 13J of the filter body 1 increases to the same extent as the gel-like semi-solid material 4K adhering to the lower outer peripheral surface 13K of the filter body 1.

[0031] (Comparative example of filtration device) Next, a filtration device 10D of the comparative example will be described in detail. Fig. 6 is a schematic cross-sectional view showing the state of gel-like semi-solid matter adhering to the outer peripheral surface of the filter in the filtration device of the comparative example immediately after the start of filter use. Fig. 7 is a schematic cross-sectional view showing the state of gel-like semi-solid matter adhering to the outer peripheral surface of the filter in the filtration device of the comparative example when the filter is due for replacement.

[0032] As shown in FIGS. 1, 6, and 7, the comparative filtration device 10D includes a cylindrical filter body 1 with a bottom that filters out impurities from electrode paste 3, which is made by mixing components constituting an active material layer 92 of a battery electrode plate 9 with a solvent 712 to form a paste, and a housing 2D that surrounds the filter body 1 and has a paste outlet 221 that communicates with an opening 11K formed in the upper end 11 of the filter body 1 and a paste inlet 212 formed opposite the lower end 12 of the filter body 1. The housing 2D also includes a housing main body 21D that houses the filter body 1 and an upper lid 22 that removably seals the upper opening 211D of the housing main body 21D. The filter body 1 is identical to the filter body 1 of the present filtration device 10. The above features are common to the present filtration device 10.

[0033] However, in the housing 2D of the filtration device 10D of the comparative example, the gap W between the housing inner wall side surface 213D and the filter outer peripheral surface 131 of the filter body 1 is formed to be the same from the upper end 11 to the lower end 12 of the filter body 1. Specifically, the gap W between the housing inner wall side surface 213D and the filter outer peripheral surface 131 of the filter body 1 is formed to be the same as the gap W1 between the housing inner wall side surface 213 at the upper end 11 of the filter body 1 of the present filtration device 10 and the filter outer peripheral surface 131 of the filter body 1. The above-mentioned content differs from the present filtration device 10.

[0034] In this case, the gap W (W1) between the housing inner wall side surface 213D and the filter outer peripheral surface 131 of the filter body 1 is uniform from the upper end 11 to the lower end 12 of the filter body 1. Therefore, as shown in FIG. 6, the electrode paste 3 flowing into the housing 2D from the paste inlet 212 approaches the filter lower outer peripheral surface 13K, which is closer to the flow path 14 where the paste pressure is low, and most of it penetrates into the filter layer 13 from the filter lower outer peripheral surface 13K side. Therefore, as shown in FIG. 7, the gel-like semi-solid material 4 adhering to the outer peripheral surface 131 of the filter body 1 increases downward, significantly narrowing the gap between the gel-like semi-solid material 4K adhering to the filter lower outer peripheral surface 13K and the housing inner wall side surface 213D. This makes it difficult for the electrode paste 3 to be supplied to the upper end 11 side of the filter body 1. Therefore, the paste pressure Q2 of the electrode paste 3 on the upper end 11 side of the filter body 1 inside the housing 2 is significantly reduced compared to the paste pressure Q1 on the lower end 12 side of the filter body 1, and the amount of gel-like semi-solid material 4J adhering to the upper outer peripheral surface 13J of the filter body 1 is significantly reduced compared to the gel-like semi-solid material 4K adhering to the lower outer peripheral surface 13K of the filter body 1. As a result, the filter body 1 cannot be used to its full lifespan.

[0035] 7, if a step occurs between the gel-like semi-solid material 4T adhering to the middle outer peripheral surface 13T of the filter body 1 and the upper semi-solid material 4J, causing pressure loss, the gap W (W1) between the housing inner wall side surface 213D and the filter outer peripheral surface 131 is constant, so paste pressure is not generated from the housing inner wall side surface 213D side. Therefore, the paste pressure Q required for the electrode paste 3 to penetrate into the filter layer 13 cannot be sufficiently secured against the upper outer peripheral surface 13J of the filter body 1. As a result, the filtering ability of the entire filter is reduced, and the life of the filter body 1 is shortened.

[0036] As described above, the present filtration device 10 can extend the life of the filter body 1 compared to the comparative example filtration device 10D, and therefore in a manufacturing method for an electrode plate 9 including a paste filtration process S2 using the present filtration device 10, the replacement cycle of the filter body 1 can be extended, and waste of electrode paste 3 associated with filter replacement can be reduced.

[0037] <Modification> The present embodiment described in detail above is merely an example and does not limit the present disclosure in any way. Therefore, the present disclosure can be improved and modified in various ways without departing from the spirit and scope of the present disclosure. Representative modifications 1 and 2 of the present filtration device 10 will be described below with reference to the drawings.

[0038] (Variation 1) FIG. 8 is a schematic cross-sectional view of a first modification of the filtration device shown in FIG. 2. As shown in FIG. 8, the filtration device 10B of the first modification includes a guide portion 5 in the housing 2 that guides the electrode paste 3 flowing in from the paste inlet 212 toward the housing inner wall side surface 213. The guide portion 5 has a protrusion 51 that protrudes tapered toward the paste inlet 212 and a cover portion 52 that is connected to the base end of the protrusion 51 and covers the lower end 12 of the filter body 1. Here, the filter body 1 and the housing 2 in the filtration device 10B of the first modification are the same as those of the filtration device 10 described above. The protrusion 51 is a conical protrusion with an acute inner angle at the tip that faces the center of the paste inlet 212, but is not necessarily limited to this. For example, a pyramidal protrusion may be used. Furthermore, the cover portion 52 is an arc-shaped cover portion that protrudes downward in an arc shape at a position close to the lower end portion 12 of the filter body 1, but this is not necessarily limited to this and may be, for example, a trapezoidal cover portion that protrudes downward in a trapezoidal shape. Furthermore, it is preferable that the outer edge of the cover portion 52 protrudes slightly outward from the outer peripheral surface 131 of the filter body 1. The guide portion 5 is attached to the lower end portion 12 of the filter body 1, but this is not necessarily limited to this and may be attached to the housing 2.

[0039] In this case, the highly viscous electrode paste 3 flowing in from the paste inlet 212 is smoothly separated toward the housing inner wall side surface 213 by the tapered protrusion 51, and the arc-shaped covering part 52 further increases the housing-side paste laminar flow 31 that flows along the housing inner wall side surface 213 toward the upper end 11 of the filter body 1. This improves the paste pressure P2 of the electrode paste 3 that permeates the upper outer peripheral surface 131J of the filter body 1, further increasing the filtering capacity of the entire filter.

[0040] (Variation 2) FIG. 9 shows a schematic cross-sectional view of a second modification of the filtration device shown in FIG. 2. As shown in FIG. 9, the filtration device 10C of the second modification is a filtration device 10C in which the housing 2 is provided with a heating device 6 that heats the electrode paste 3 flowing on the side of the inner wall 213 of the housing. Here, the filter body 1 and the housing 2 in the filtration device 10C of the second modification are the same as those of the filtration device 10 described above. The heating device 6 is preferably a planar heating element 6M formed with a substantially uniform thickness along the outer wall surface 214 of the housing 2. It is even more preferable that the heating device 6 extend to the bottom outer wall surface 215 of the housing 2.

[0041] In this case, the viscosity of the housing-side paste laminar flow 31 can be reduced by heating the electrode paste 3 flowing on the housing inner wall side surface 213. This reduces the viscous resistance of the housing-side paste laminar flow 31 against the housing inner wall side surface 213, allowing more of the electrode paste 3 flowing in from the paste inlet 212 to be supplied along the housing inner wall side surface 213 toward the upper end 11 of the filter body 1. This increases the paste pressure P2 of the electrode paste 3 permeating into the upper outer peripheral surface 131J of the filter body 1, further improving the filtering capacity of the entire filter. [Explanation of symbols]

[0042] 1 Filter body 2. Housing 3 Electrode paste 5 Guide section 6 Heating device 9 Electrode plate 10,10B,10C filtration device 11 Upper end 11K aperture 12 Lower end 13K Filter lower outer surface 14, 14K semi-solid 51 Protrusion 52 Cover 77 Filter replacement control unit 92 Active material layer 131 Filter outer surface 212 Paste inlet 213 Housing inner wall side 221 Paste outlet 712 Solvent P, P0, P1, P2, P4 Paste pressure △P pressure difference △PK reference value T Maximum thickness W, W1, W2 gap Z1, Z2 pressure gauge

Claims

1. a cylindrical filter body with a bottom for filtering out foreign matter in an electrode paste obtained by kneading components constituting an active material layer of an electrode plate of a battery into a paste form with a solvent; a housing surrounding the filter body and having a paste outlet communicating with an opening formed at an upper end of the filter body, and a paste inlet formed at a position opposite to a lower end of the filter body, The housing is formed so that the gap between the inner wall side of the housing and the outer peripheral surface of the filter of the filter body gradually widens from the upper end to the lower end of the filter body. Filtration device.

2. 2. The filtration device according to claim 1, The gap between the housing inner wall side surface and the filter outer peripheral surface at the lower end of the filter body is formed larger than the gap between the housing inner wall side surface and the filter outer peripheral surface at the upper end of the filter body by at least the maximum thickness of deposits adhering to the lower outer peripheral surface of the filter. Filtration device.

3. 2. The filtration device according to claim 1, a guide portion provided within the housing for guiding the electrode paste flowing in from the paste inlet toward a side surface of the inner wall of the housing; The guide portion has a protrusion portion that protrudes in a tapered shape toward the paste inlet, and a cover portion that is connected to a base end of the protrusion portion and covers a lower end of the filter body. Filtration device.

4. 2. The filtration device according to claim 1, The housing is provided with a heating device for heating the electrode paste flowing along the side of the inner wall of the housing. Filtration device.

5. The filtration device according to any one of claims 1 to 4, a pressure gauge for measuring the paste pressure of the electrode paste flowing between the paste inlet and the paste outlet, and a filter replacement control unit for outputting a replacement signal for the filter body when the pressure difference of the paste pressure measured by the pressure gauge is greater than a reference value; Filtration device.

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