Manufacturing method of electrode for secondary battery and manufacturing device of electrode for secondary battery

Abstract

To suppress deterioration of the quality of an electrode for the secondary battery by removing foreign matter from the active material particles.SOLUTION: A method for manufacturing an electrode 2 for a secondary battery includes a mixing step S2 of mixing active material particles 4, a removal step S3 of removing foreign matter F from the mixed active material particles 4, and a forming step S4 of forming the active material particles 4 from which the foreign matter F has been removed into a sheet on a current collector 3. In the mixing step S2, the active material particles 4 are placed in a container 70 including a bottom 80 with ventilation holes 79. In the removal step S3, gas A is caused to flow from below to above the active material particles 4 placed in the container 70 through the ventilation holes 79, thereby removing the foreign matter F from the active material particles 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an electrode for a secondary battery and an apparatus for manufacturing an electrode for a secondary battery. [Background technology]

[0002] For example, as shown in Patent Document 1, electrodes constituting secondary batteries are generally produced by mixing active material particles, supplying the mixed active material particles to a current collector, and forming the active material particles supplied to the current collector into a sheet shape. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-92622 Summary of the Invention [Problem to be solved by the invention]

[0004] When mixing the active material particles, there is a possibility that foreign matter may be mixed into the active material particles, which may lead to a deterioration in the quality of the electrode and ultimately to a deterioration in the quality of the secondary battery.

[0005] The present disclosure has been made in view of the above points, and its object is to prevent deterioration in the quality of an electrode for a secondary battery by removing foreign matter from active material particles. [Means for solving the problem]

[0006] The method for manufacturing an electrode for a secondary battery according to the present disclosure includes a mixing step of mixing active material particles, a removal step of removing foreign matter from the mixed active material particles, and a forming step of forming the active material particles from which the foreign matter has been removed into a sheet on a current collector. In the mixing step, the active material particles are placed in a container having a bottom with an air vent, and in the removal step, the foreign matter is removed from the active material particles by flowing gas from below through the air vent from above the active material particles placed in the container.

[0007] The manufacturing apparatus for electrodes for secondary batteries according to the present disclosure comprises a mixing section in which active material particles are mixed, a removal section in which foreign matter is removed from the mixed active material particles, and a formation section in which the active material particles from which the foreign matter has been removed are formed into a sheet on a current collector, wherein in the mixing section, the active material particles are placed into a container having a bottom with an air vent, and in the removal section, gas is caused to flow from below to above the active material particles placed in the container through the air vent, thereby removing the foreign matter from the active material particles. [Effects of the Invention]

[0008] According to the present disclosure, by removing foreign matter from active material particles, deterioration in the quality of electrodes for secondary batteries can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a manufacturing apparatus for an electrode for a secondary battery according to the first embodiment. [Figure 2] FIG. 2 shows the active material particles and binder according to the first embodiment. [Figure 3] FIG. 3 shows a mixture of active material particles according to the first embodiment. [Figure 4] FIG. 4 shows the removal of foreign matter from active material particles according to the first embodiment. [Figure 5] FIG. 5 is a flowchart showing a method for manufacturing an electrode for a secondary battery according to the first embodiment. [Figure 6]FIG. 6 is a schematic diagram showing a manufacturing apparatus for an electrode for a secondary battery according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0011] First Embodiment A first embodiment will be described.

[0012] (Secondary battery) The secondary battery includes a lithium-ion secondary battery, a lithium-sulfur secondary battery, etc. The electrode includes an active material layer formed on a current collector. The electrode includes a positive electrode and a negative electrode. The active material layer includes an active material and a binder. The active material layer may further include a conductive additive.

[0013] Known materials can be used for the current collector, active material, binder, and conductive additive. For example, in the case of a lithium-ion secondary battery, aluminum foil or the like is used for the positive electrode current collector, and copper foil or the like is used for the negative electrode current collector. For example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium iron phosphate (LiFePO4), or the like is used for the positive electrode active material. Graphite, silicon, lithium metal, or the like is used for the negative electrode active material. Polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or the like is used for the binder. Carbon materials such as carbon black and acetylene black are used for the conductive additive.

[0014] (Electrode manufacturing equipment for secondary batteries) 1 schematically shows a manufacturing apparatus 1 for manufacturing an electrode 2 for a secondary battery. The manufacturing apparatus 1 is for manufacturing an electrode 2 for a secondary battery. The manufacturing apparatus 1 for manufacturing an electrode 2 for a secondary battery includes a conveying section 10, a mixing section 20, a removing section 30, a supplying section 40 as part of a forming section 90, a molding section 50 as part of the forming section 90, and a heat pressing section 60.

[0015] The conveying unit 10 is configured, for example, by a roll-to-roll mechanism. The conveying unit 10 conveys the current collector 3. The conveying unit 10 includes a delivery roll 11, a take-up roll 12, and two guide rolls 13. In the conveying direction of the current collector 3 in the conveying unit 10, the delivery roll 11 is disposed on the upstream side, the take-up roll 12 is disposed on the downstream side, and the guide roll 13 is disposed between the delivery roll 11 and the take-up roll 12.

[0016] The current collector 3 is fed from a feed roll 11, transported from the upstream side to the downstream side along a predetermined transport path, and then taken up by a take-up roll 12. The current collector 3 is supported and guided by a guide roll 13 between the feed roll 11 and the take-up roll 12.

[0017] The mixing section 20 and the removal section 30 will be described later.

[0018] The supply unit 40 is disposed downstream of the delivery roll 11 and upstream of the take-up roll 12 in the conveying unit 10. In the supply unit 40, the active material particles 4 are supplied to the current collector 3. The supply unit 40 is configured by, for example, a hopper. The active material particles 4 are stored in the supply unit 40. When the hopper is opened, the active material particles 4 stored in the supply unit 40 are supplied to the current collector 3 being conveyed by the conveying unit 10. In addition to the active material particles 4, the supply unit 40 also stores a binder. The supply unit 40 may further store a conductive additive.

[0019] The shaping section 50 is disposed downstream of the supply section 40 and upstream of the take-up roll 12 of the transport section 10. In the shaping section 50, the active material particles 4 supplied to the current collector 3 are shaped into a sheet. The shaping section 50 is composed of, for example, a pair of rolling rolls 51. The shaping section 50 adjusts the gap between the rolling rolls 51 and the transported current collector 3. The shaping section 50 adjusts the thickness of the active material particles 4 shaped into a sheet (hereinafter referred to as "active material particle sheet 5"). The shaping section 50 rolls the active material particles 4. The shaping section 50 may be composed of a squeegee.

[0020] In this manner, in the forming section 90 (supply section 40 and shaping section 50), the active material particles 4 are formed into a sheet shape on the current collector 3.

[0021] The heat pressing section 60 is disposed downstream of the molding section 50 and upstream of the take-up roll 12 of the conveying section 10. In the heat pressing section 60, the active material particles 4 formed into a sheet shape (active material particle sheet 5) are heat pressed to form an active material layer 6 on the current collector 3. In this way, an electrode 2 is formed in which the active material layer 6 is formed on the current collector 3.

[0022] The heat press unit 60 is composed of, for example, a planar heating unit 61 that heats the active material particle sheet 5 in a non-contact manner, and a heat roll press unit 62 that is arranged downstream of the planar heating unit 61. The planar heating unit 61 is composed of, for example, an infrared lamp. The heat roll press unit 62 is composed of, for example, a pair of heat rolls.

[0023] In the hot pressing section 60, the binder 7 (described below) coated on the surfaces 4a of the active material particles 4 melts, and the active material particles 4 are compressed, thereby binding the active material particles 4 to each other and to the current collector 3 via the binder 7. This results in an active material layer 6 having low contact resistance between the active material particles 4 and strong adhesive strength between the active material particles 4 and the current collector 3.

[0024] The electrode 2 formed in the heat press section 60 is taken up by the take-up roll 12 of the transport section 10 arranged downstream of the heat press section 60 .

[0025] (Active material particles and binder) FIG. 2 shows active material particles 4 and a binder 7. The surfaces 4a of the active material particles 4 are coated with a dispersed binder 7 and a conductive additive 8. For example, the active material particles 4 are dispersed in a solvent in which the binder 7 and the conductive additive 8 are dissolved, and then the solvent is evaporated. As a result, the surfaces 4a of the active material particles 4 are coated with a dispersed binder 7 and a conductive additive 8. Alternatively, the active material particles 4 may be mixed with the binder 7 and the conductive additive 8, each having a particle size smaller than that of the active material particles 4, and heated. When the surfaces 4a of the active material particles 4 are not coated with the conductive additive 8, a mixture of the active material particles 4 (whose surfaces 4a are coated with the binder 7) and the conductive additive 8 may be supplied to the current collector 3. The conductive additive 8 may not be necessary.

[0026] (Mixing section and removal section) 3 shows the mixing of the active material particles 4. The mixing section 20 and the removal section 30 are located upstream of the supply section 40 in the flow of the active material particles 4.

[0027] The active material particles 4 are mixed in the mixing section 20. The foreign matter F is removed from the mixed active material particles 4 in the removal section 30. In this example, the mixing section 20 and the removal section 30 are integrated.

[0028] The mixing section 20 and the removal section 30 include a container 70. The container 70 is formed, for example, in a cylindrical shape having an axis extending vertically. The container 70 is covered with front, rear, left, and right side walls 71, an upper wall 72, and a lower wall 73.

[0029] A left communication passage 74 is provided in the left wall 71a of the side wall 71 of the container 70. The left communication passage 74 penetrates the left wall 71a from left to right. The left communication passage 74 extends leftward and upward from the left wall 71a. The left communication passage 74 extends rightward and downward as it approaches the left wall 71a. The left communication passage 74 connects the inside and outside of the container 70 at the left wall 71a.

[0030] A right communication passage 75 is provided in the right wall 71b of the side wall 71 of the container 70. The right communication passage 75 penetrates the right wall 71b from left to right. The right communication passage 75 extends rightward and downward from the right wall 71b. The right communication passage 75 extends rightward and downward as it moves away from the right wall 71b. The right communication passage 75 communicates between the inside and outside of the container 70 at the right wall 71b.

[0031] An upper communication passage 76 is provided in the upper wall 72 of the container 70. The upper communication passage 76 passes through the upper wall 72 in the vertical direction. The upper communication passage 76 extends upward from the upper wall 72. The upper communication passage 76 extends upward as it moves away from the upper wall 72. The upper communication passage 76 communicates the inside and outside of the container 70 at the upper wall 72.

[0032] A lower communication passage 77 is provided in the lower wall 73 of the container 70. The lower communication passage 77 passes through the lower wall 73 in the vertical direction. The lower communication passage 77 extends downward from the lower wall 73. The lower communication passage 77 extends upward as it approaches the lower wall 73. The lower communication passage 77 communicates the inside and outside of the container 70 at the lower wall 73.

[0033] A current rectifying plate 78 is disposed within the container 70 below the left communication passage 74 and the right communication passage 75 and above the lower communication passage 77 (lower wall 73). The current rectifying plate 78 is plate-shaped. The current rectifying plate 78 has thickness in the top and bottom directions and extends in the front-to-back and left-to-right directions. The current rectifying plate 78 has a plurality of ventilation holes 79. The ventilation holes 79 are formed in the shape of slits. The inner diameter of the ventilation holes 79 is preferably smaller than the outer diameter of the active material particles 4. The ventilation holes 79 may be porous.

[0034] The area in the container 70 where the lower communication passage 77 (lower wall 73) and the rectifying plate 78 are arranged is referred to as the bottom 80. That is, the container 70 includes the bottom 80 in which the ventilation holes 79 are provided.

[0035] In the mixing section 20, the active material particles 4 are introduced into the container 70 through the left communication passage 74. As described above, the surfaces 4a of the active material particles 4 are coated with a dispersed binder 7 and a conductive additive 8. The active material particles 4 (whose surfaces 4a are coated with the binder 7 and the conductive additive 8) are contained in the container 70. The active material particles 4 are placed on a rectifying plate 78.

[0036] Bead particles B are pre-stored in the container 70. The bead particles B are different from the active material particles 4. The bead particles B are also different from the binder 7 and the conductive additive 8. The bead particles B are also different from the foreign matter F described below. The bead particles B are preferably made of a material with low conductivity. The bead particles B are made of, for example, ceramic. The bead particles B are larger than the active material particles 4.

[0037] In the mixing section 20, the active material particles 4 (whose surfaces 4a are coated with the binder 7 and the conductive additive 8) are mixed together with the bead particles B in the container 70. In other words, in the mixing section 20, the bead particles B are mixed together with the active material particles 4 (whose surfaces 4a are coated with the binder 7 and the conductive additive 8) in the container 70.

[0038] When the active material particles 4 are mixed, there is a possibility that foreign matter F may be mixed into the active material particles 4. If foreign matter F is mixed into the active material particles 4, it may lead to a deterioration in the quality of the electrode 2 and ultimately to a deterioration in the quality of the secondary battery. The foreign matter F is classified into foreign matter Fa, which is heavier than the active material particles 4, and foreign matter Fb, which is lighter than the active material particles 4. The foreign matter F is, for example, a metal piece peeled off from a pipe or a container 70. In this embodiment, the foreign matter F is removed from the active material particles 4 by applying a method described below. This prevents a deterioration in the quality of the electrode 2 for a secondary battery.

[0039] 4 shows the removal of foreign matter F from active material particles 4. The lower communication passage 77 is connected to an air pump 81 serving as a gas pump. The air pump pumps air A as a gas. The air A pumped by the air pump is introduced into the container 70 through the lower communication passage 77. A heater 82 is provided midway through the lower communication passage 77. The heater 82 heats the air A flowing through the lower communication passage 77.

[0040] Air A flows from bottom to top within container 70. Within container 70, air A passes from bottom to top through ventilation holes 79 in straightening plate 78. Air A flows further upward within container 70 and is discharged to the outside of container 70 through upper communication passage 76. In removal section 30, air A (hot air) heated (by heater 82) is caused to flow within container 70.

[0041] In the removal unit 30, the active material particles 4 are floated by the air A above the rectifying plate 78 at the bottom 80 of the container 70. In the removal unit 30, foreign matter Fa that is heavier than the active material particles 4 remains on the rectifying plate 78 at the bottom 80 of the container 70. The heavy foreign matter Fa remaining on the rectifying plate 78 is removed from the container 70 during regular maintenance or the like.

[0042] In the removal section 30, the active material particles 4 remain above the straightening plate 78 at the bottom 80 of the container 70 and below the upper wall 72 of the container 70. In the removal section 30, foreign matter Fb that is lighter than the active material particles 4 is carried by the air A and discharged to the outside of the container 70 through the upper communicating passage 76.

[0043] In the removal section 30, foreign matter F is removed from the mixed active material particles 4. In the removal section 30, air A is made to flow from below to above the active material particles 4 that have been placed in a container 70 and placed on a rectifying plate 78 through ventilation holes 79 in the rectifying plate 78, thereby removing the foreign matter F from the active material particles 4. The active material particles 4 form a fluidized bed.

[0044] The active material particles 4 from which the foreign matter F has been removed in the removal unit 30 are sent to the supply unit 40 through the right communication passage 75. In the supply unit 40, the active material particles 4 from which the foreign matter F has been removed are supplied to the current collector 3. In the forming unit 50, the active material particles 4 supplied to the current collector 3 are formed into a sheet shape to become an active material particle sheet 5. In summary, in the forming unit 90 (supply unit 40 and forming unit 50), the active material particles 4 from which the foreign matter F has been removed are formed into a sheet shape on the current collector 3.

[0045] In the hot pressing section 60, the active material particles 4 formed in a sheet shape (active material particle sheet 5) are hot pressed to form an active material layer 6 on the current collector 3. In this way, an electrode 2 is produced in which the active material layer 6 is formed on the current collector 3.

[0046] (Method of manufacturing electrodes for secondary batteries) 5 is a flowchart showing a method for manufacturing the secondary battery electrode 2. The method for manufacturing the secondary battery electrode 2 includes a preparation step S1, a mixing step S2, a removal step S3, a supply step S4a as part of the formation step S4, a molding step S4b as part of the formation step S4, and a heat-pressing step S5.

[0047] As shown in FIG. 2, in the preparation step S1, active material particles 4, a binder 7, and a conductive additive 8 are prepared. Specifically, for example, in the preparation step S1, the active material particles 4 are dispersed in a solvent in which the binder 7 and the conductive additive 8 are dissolved, and then the solvent is evaporated. As a result, in the preparation step S1, the surfaces 4a of the active material particles 4 are coated with the binder 7 and the conductive additive 8 in a dispersed state. Alternatively, in the preparation step S1, the active material particles 4, the binder 7 and the conductive additive 8 having particle sizes smaller than those of the active material particles 4, and the binder 7 and the conductive additive 8 may be mixed and heated.

[0048] As shown in FIG. 3, in the mixing step S2, the active material particles 4 (whose surfaces 4a are coated with the binder 7 and the conductive additive 8) are mixed in the container 70. In the mixing step S2, the left communicating passage 74 is opened. In the mixing step S2, the active material particles 4 are introduced into the container 70 through the left communicating passage 74. In the mixing step S2, the active material particles 4 introduced into the container 70 are placed on the current plate 78. In the mixing step S2, the right communicating passage 75 is closed. That is, in the mixing step S2, the supply of the active material particles 4 from the container 70 to the supply unit 40 through the right communicating passage 75 is stopped. In the mixing step S2, the supply of air A from the air pump 81 into the container 70 through the lower communicating passage 77 is stopped.

[0049] In the mixing step S2, the bead particles B are mixed with the active material particles 4 in the container 70. The bead particles B are accommodated in the container 70 in advance.

[0050] There is a possibility that foreign matter F is mixed in the active material particles 4 introduced into the container 70 in the mixing step S2. Note that the bead particles B are different from the foreign matter F. The foreign matter F is, for example, metal pieces peeled off from the piping or the container 70. The foreign matter F includes foreign matter Fa which is heavier than the active material particles 4, and foreign matter Fb which is lighter than the active material particles 4.

[0051] 4, in the removal step S3, foreign matter F is removed from the mixed active material particles 4. In the removal step S3, the left communication passage 74 is closed. That is, in the removal step S3, the introduction of the active material particles 4 into the container 70 through the left communication passage 74 is stopped. In the removal step S3, the right communication passage 75 is opened. That is, in the removal step S3, the active material particles 4 are fed from inside the container 70 to the supply unit 40 through the right communication passage 75. In the removal step S3, air A is supplied from the air pump 81 into the container 70 through the lower communication passage 77.

[0052] Here, the air A flowing through the lower communication passage 77 is heated by the heater 82. In the removal step S3, the air A (hot air) heated (by the heater 82) is caused to flow inside the container 70.

[0053] In the removal step S3, the air A flows from bottom to top within the container 70. In the removal step S3, the air A passes from bottom to top through the ventilation holes 79 of the rectifying plate 78 within the container 70. In the removal step S3, the air A flows further upward within the container 70 and is discharged to the outside of the container 70 through the upper communicating passage 76.

[0054] In the removal step S3, the active material particles 4 are floated by the air A above the current plate 78 at the bottom 80 of the container 70. In the removal step S3, foreign matter Fa that is heavier than the active material particles 4 remains on the current plate 78 at the bottom 80 of the container 70.

[0055] In the removal step S3, the active material particles 4 remain above the straightening plate 78 at the bottom 80 of the container 70 and below the upper wall 72 of the container 70. In the removal step S3, foreign matter Fb that is lighter than the active material particles 4 is carried by the air A and discharged to the outside of the container 70 through the upper communicating passage 76.

[0056] In this manner, in the removal step S3, air A is caused to flow from below to above the active material particles 4 that have been placed in the container 70 and placed on the rectifying plate 78 through the ventilation holes 79 of the rectifying plate 78, thereby removing the foreign matter F from the active material particles 4. In the removal step S3, the foreign matter F is removed from the mixed active material particles 4. The active material particles 4 form a fluidized bed.

[0057] In the removing step S3, the active material particles 4 from which the foreign matter F has been removed are sent to the supply unit 40 through the right communicating passage 75.

[0058] 1, in the supplying step S4a, the active material particles 4 from which the foreign matter F has been removed are supplied to the current collector 3. When the surfaces 4a of the active material particles 4 are not coated with the conductive additive 8, the conductive additive 8 may be supplied to the current collector 3 together with the active material particles 4 (whose surfaces 4a are coated with the binder 7) in the supplying step S4a.

[0059] 1, in the forming step S4b, the active material particles 4 supplied to the current collector 3 are formed into a sheet shape. The active material particles 4 formed into a sheet shape are called an active material particle sheet 5.

[0060] In summary, in the forming step S4 (supplying step S4a and shaping step S4b), the active material particles 4 from which the foreign matter F has been removed in the removing step S3 are formed into a sheet shape on the current collector 3.

[0061] 1, in the hot pressing step S5, active material particles 4 formed into a sheet shape (active material particle sheet 5) are hot pressed to form an active material layer 6 on the current collector 3. In this way, an electrode 2 is formed in which the active material layer 6 is formed on the current collector 3.

[0062] (Action and effect) Air A is caused to flow from below to above the active material particles 4 placed in the container 70 through the ventilation holes 79 of the current plate 78 at the bottom 80 of the container 70. This removes foreign matter F from the active material particles 4. By removing the foreign matter F from the active material particles 4 in this manner, deterioration in the quality of the electrode 2 for a secondary battery can be suppressed.

[0063] The active material particles 4 are floated by the air A above the current plate 78 at the bottom 80 of the container 70. Foreign matter Fa heavier than the active material particles 4 remains on the current plate 78 at the bottom 80 of the container 70. This allows the foreign matter Fa heavier than the active material particles 4 to be removed from the active material particles 4.

[0064] The active material particles 4 accumulate above the straightening plate 78 at the bottom 80 of the container 70 and below the upper wall 72 of the container 70. Foreign matter Fb lighter than the active material particles 4 is carried by the air A and discharged to the outside of the container 70 through the upper communication passage 76. This allows the foreign matter Fb lighter than the active material particles 4 to be removed from the active material particles 4.

[0065] The bead particles B are mixed with the active material particles 4 in the container 70. By colliding with the active material particles 4, the bead particles B are prevented from agglomerating together, and the active material particles 4 can be dispersed.

[0066] Heated air A (hot air) (by heater 82) is circulated inside the container 70. This dries the active material particles 4, reducing the liquid bridging force acting between the active material particles 4 and making it easier for the active material particles 4 to disperse.

[0067] The manufacturing method (manufacturing apparatus 1) of the electrode 2 according to this embodiment employs a so-called dry process using the hot pressing step S5 (hot pressing unit 60), thereby eliminating the need for a slurry drying step and a solvent vapor recovery and regeneration step, as compared to a manufacturing method (manufacturing apparatus) of an electrode using a so-called wet process using a slurry. As a result, the manufacturing cost of the electrode 2 can be significantly reduced.

[0068] Second Embodiment A second embodiment will be described. In the following description, the same components as those in the above embodiment will be denoted by the same reference numerals, and detailed description will be omitted. Figure 6 schematically shows an apparatus for manufacturing an electrode 2 for a secondary battery according to the second embodiment.

[0069] In the above embodiment, the forming section 90 (forming step S4) was composed of a supply section 40 (supply step S4a) and a molding section 50 (molding step S4b) separately, but this is not limited to this, and for example, the two may be integrated.

[0070] Specifically, the forming unit 90 includes a hopper 91, a pair of rollers 92, and a forming roller 93. In the forming unit 90, the active material particles 4 are dropped from the hopper 91 in which the active material particles 4 are stored into the gap between the pair of rollers 92, and the sheet-like active material particles 4 are supplied through the gap between the pair of rollers 92 to the current collector 3 and formed by the forming roller 93.

[0071] In the forming section 90, the active material particles 4 are formed into a sheet shape on the current collector 3. In the forming step S4, the active material particles 4 are formed into a sheet shape on the current collector 3.

[0072] <Other embodiments> Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

[0073] Gas A does not have to be air.

[0074] In the above embodiment, the mixing unit 20 and the removal unit 30 are integrated as the container 70, but this is not limiting and they may be separate. For example, the container constituting the mixing unit 20 and the container constituting the removal unit 30 may be connected by a pipe.

[0075] The mixing step S2 and the removing step S3 may be carried out simultaneously.

[0076] The conductive additive 8 may be omitted.

[0077] Bead particles B may be omitted.

[0078] An electrode manufacturing method (manufacturing apparatus 1) using a so-called wet process using a slurry may also be applied. [Industrial Applicability]

[0079] The present disclosure is applicable to a method for manufacturing an electrode for a secondary battery and an apparatus for manufacturing an electrode for a secondary battery, and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0080] 1 Manufacturing equipment 2 electrodes 3 Current collector 4 Active material particles 4a surface 5. Active material particle sheet 6 Active material layer 7. Binder 8 Conductive additives 10 Conveying section 11 Sending Roll 12 Winding roll 13 Guide Roll 20 Mixing section 30 Removal part 40 Supply section 50 Molding section 51 Rolling mill 60 Heat Press Section 61 Planar heating section 62 Heating roll press section 70 containers 71 Side wall 71a Left side wall 71b Right side wall 72 Upper Wall 73 Lower Wall 74 Left connecting passage 75 Right communication passage 76 Upper passageway 77 Lower passageway 78 Rectifier plate 79 Ventilation holes 80 bottom 81 Air pump (gas pump) 82 Heater 90 Formation part 91 Hopper 92 Pair of Rollers 93 Forming roller A. Air (gas) F Foreign object Fa Foreign body Fb foreign body B. Bead particles S1 Preparation process S2 mixing process S3 removal process S4 forming process S4a Supply process S4b Molding process S5 Heat pressing process

Claims

1. a mixing step of mixing active material particles; a removing step of removing foreign matter from the mixed active material particles; a forming step of forming the active material particles from which the foreign matter has been removed into a sheet shape on a current collector, In the mixing step, the active material particles are placed in a container having a bottom with a ventilation hole; In the removal step, the foreign matter is removed from the active material particles by flowing gas from below through the ventilation holes toward the active material particles placed in the container.

2. 2. The method for manufacturing an electrode for a secondary battery according to claim 1, wherein in the removing step, the active material particles are floated above the bottom by the gas, and the foreign matter heavier than the active material particles remains at the bottom.

3. 3. The method for manufacturing an electrode for a secondary battery according to claim 1, wherein in the mixing step, bead particles are mixed with the active material particles in the container.

4. 3. The method for manufacturing an electrode for a secondary battery according to claim 1, wherein the removing step causes the heated gas to flow.

5. a mixing section in which active material particles are mixed; a removal section in which foreign matter is removed from the mixed active material particles; a forming section in which the active material particles from which the foreign matter has been removed are formed into a sheet shape on a current collector, In the mixing section, the active material particles are poured into a container having a bottom with a ventilation hole; In the removal section, gas is caused to flow from below to above the active material particles through the ventilation holes, thereby removing the foreign matter from the active material particles.

6. 6. The manufacturing apparatus for an electrode for a secondary battery according to claim 5, wherein in the removal section, the active material particles are floated above the bottom by the gas, and the foreign matter heavier than the active material particles remains at the bottom.

7. 7. The manufacturing apparatus for an electrode for a secondary battery according to claim 5, wherein in the mixing section, bead particles are mixed with the active material particles in the container.

8. 7. The manufacturing apparatus for an electrode for a secondary battery according to claim 5, wherein the heated gas is caused to flow in the removal section.

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