JP2022150670A - Manufacturing method of electrode plate - Google Patents

Abstract

To provide a manufacturing method of an electrode plate capable of appropriately forming an active material layer on a current collecting foil in a dry process without using magnetic carrier powder.SOLUTION: A manufacturing method of an electrode plate 1 includes supply steps S3 and S6 of supplying, to a film formation region MR1, an active material granulated powder 42 composed of active material granulated particles 41 in which active material composite particles 21 in which binder particles 13P are attached to active material particles 11 are bonded to each other is deposited and shaped into a layer of uniform thickness, uncompressed layer forming steps S4 and S7 of blowing the active material granulated particles 41 toward a current collector foil 3 by the electrostatic force Fs1 in the film formation region MR1, depositing the active material granulated particles 41 on the current collector foil 3, and forming uncompressed active material layers 5X and 6X, and pressing steps S5 and S8 of heat-pressing the uncompressed active material layers 5X and 6X and the current collector foil 3.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing an electrode plate having an active material layer containing active material particles and a binder on a current collector foil.

2. Description of the Related Art Electrode plates, such as positive electrode plates and negative electrode plates used in batteries, are known in which an active material layer containing active material particles and a binder is formed on a collector foil. Such an electrode plate is manufactured, for example, by the following method. That is, an active material powder in which active material particles are aggregated and a binder powder in which binder particles are aggregated are mixed in advance, and active material composite particles in which the binder particles are attached to the active material particles are obtained. An active material composite powder is obtained. Then, this active material composite powder is mixed with separately prepared magnetic carrier powder in which magnetic carrier particles are aggregated to obtain composite carrier particles in which a large number of active material composite particles are electrostatically adsorbed to individual magnetic carrier particles. A composite carrier powder is obtained.

After that, the composite carrier particles forming the composite carrier powder are magnetically attracted to the roll surface of the magnet roll. Subsequently, by rotating the magnet roll, the composite carrier particles magnetically attracted to the roll surface are transported to the gap (film formation area) between the magnet roll and the collector foil transported by the backup roll. Next, in this film formation region, the active material composite particles among the composite carrier particles are blown from the roll surface toward the current collector foil by electrostatic force, depositing the active material composite particles on the current collector foil, and uncompressed to form an uncompressed active material layer of After that, the electrode plate composed of the uncompressed active material layer and the current collector foil is hot-pressed to form an active material layer from the uncompressed active material layer. Incidentally, Patent Document 1 can be cited as a conventional technique related to the manufacturing method of this electrode plate.

JP 2020-149862 A

In the above-described manufacturing method, the active material layer can be formed in a dry process without using an active material paste in which the active material particles and the binder particles are dispersed in the dispersion medium. It is unnecessary, and the productivity of the electrode plate is high.
However, the above manufacturing method requires a magnetic carrier powder and a step of mixing the active material composite powder and the magnetic carrier powder to form a composite carrier powder. There has been a demand for a new method of manufacturing electrode plates without using a body.

SUMMARY OF THE INVENTION The present invention has been made in view of the current situation, and provides a method for manufacturing an electrode plate that can appropriately form an active material layer on a current collector foil in a dry process without using magnetic carrier powder. be.

One aspect of the present invention for solving the above problems is a method for manufacturing an electrode plate provided with an active material layer containing active material particles and a binder on a current collector foil, wherein the electrode plate is bound to the active material particles. a supply step of accumulating and shaping the active material granulated powder in which the active material granulated particles in which the active material composite particles to which the agent particles are attached are aggregated into a layer having a uniform thickness, and supplying the powder to a film formation region; In the film formation region, the active material granulated particles are blown toward the current collector foil by electrostatic force, the active material granulated particles are deposited on the current collector foil, and the uncompressed uncompressed active material An electrode plate comprising: an uncompressed layer forming step of forming a layer; and a pressing step of hot-pressing the uncompressed active material layer and the current collector foil to form the active material layer from the uncompressed active material layer. is a manufacturing method.

First, the present inventors used the active material composite powder, which is a mixture of the active material powder and the binder powder, as it is, and performed the supply step, the uncompressed layer forming step, and the pressing step to form an electrode plate. tried to manufacture. However, it has been found that it is difficult to properly form an uncompressed active material layer on the current collector foil by this manufacturing method. The reason for this is that the active material composite powder has a strong cohesive force between the active material composite particles, so even if an electrostatic force is applied to the active material composite particles, it is difficult for the active material composite particles to fly toward the current collector foil. It was thought that

On the other hand, in the above-described electrode plate manufacturing method, active material granulated powder made of active material granulated particles in which active material composite particles in which binder particles are attached to active material particles are bonded to each other is used. A supply step, an uncompressed layer forming step and a pressing step are performed. The cohesive force of active material granulated particles, which are relatively large particle diameters formed by combining a plurality of active material composite particles, is weaker than that of active material composite particles with relatively small particle diameters. Therefore, in the uncompressed layer forming step, the granulated active material particles can be appropriately caused to fly toward the current collector foil by electrostatic force, and the uncompressed active material layer can be appropriately formed on the current collector foil. Then, the active material layer can be properly formed in the pressing process.

Examples of the "active material composite particles" include, for example, active material composite particles in which only binder particles are attached to active material particles, and in addition to active material particles and binder particles, other particles such as conductive particles are further included. Adhered active material composite particles and the like can be mentioned.
In the "supply step", as a method of depositing and shaping the active material granulated powder into a layer of uniform thickness and supplying it to the film formation region, for example, the active material granulated powder is deposited on the roll surface of the supply roll with a uniform thickness are deposited and shaped in layers, and by rotating the supply roll, the deposited layer of the active material granulated powder is supplied to the film forming area, or the active material granulated powder is deposited on the belt surface of the supply belt so as to have a uniform thickness. For example, a method of depositing and shaping in layers and supplying the deposited layer of the active material granulated powder to the film-forming region by moving a supply belt.

Further, in the above electrode plate manufacturing method, it is preferable that the supply step uses the active material granulated powder having an angle of repose θ≦40.0 (deg).

In the method for manufacturing an electrode plate described above, in the supply step, a highly fluid active material granulated powder having a repose angle θ of θ≦40.0 (deg) is used. Such a highly fluid active material granulated powder has a particularly weak cohesive force between particles. The uncompressed active material layer can be formed more appropriately, and the active material layer can be more appropriately formed in the pressing process.

The "angle of repose θ of the active material granulated powder" is obtained by the following measuring method. That is, the angle of repose θ is determined by dropping the active material granulated powder from a funnel placed at a predetermined height onto a horizontal substrate to form a conical powder deposit. It is obtained by calculating the base angle from the diameter and height of the object. Specifically, the angle of repose θ is measured in accordance with JIS R 9301-2-2:1999 “Method for measuring physical properties of alumina powder-2: angle of repose”.

Further, in the method for manufacturing an electrode plate described above, prior to the supply step, the active material granulated powder in which the active material granulated particles are aggregated from the active material composite powder in which the active material composite particles are aggregated. The granulated powder preparation step includes a sheet forming step of pressing the active material composite powder to obtain a sheet-like green compact, and a sheet-like compact An electrode comprising: a crushing step of crushing a green compact to obtain a crushed powder; and a sizing step of regulating the crushed powder to obtain a sized powder having a particle size within a predetermined particle size range. It is good to consider it as the manufacturing method of a board.

The electrode plate manufacturing method described above further includes a granulated powder preparation step of preparing an active material granulated powder from the active material composite powder. , a crushing process and a sizing process. By performing such a granulated powder production step, it is possible to easily produce an active material granulated powder having desired fluidity at an angle of repose θ≦40.0 (deg). Therefore, by performing the supplying step and the uncompressed layer forming step using this active material granulated powder, the uncompressed active material layer can be formed more appropriately, and the active material layer can be more appropriately formed in the pressing step.

Further, in the method for manufacturing an electrode plate described above, the granulated powder producing step classifies the sized powder obtained in the granule sizing step to have a particle size within a predetermined particle size range. It is preferable that the method for manufacturing an electrode plate further includes a classification step for obtaining classified powder.

In the electrode plate manufacturing method described above, the granulated powder preparation step further includes the classification step described above. Thereby, an active material granulated powder having more suitable fluidity can be easily produced. Therefore, by performing the supplying step and the uncompressed layer forming step using this active material granulated powder, the uncompressed active material layer can be formed more appropriately, and the active material layer can be more appropriately formed in the pressing step.

4 is a perspective view of an electrode plate according to Embodiments 1 and 2 and Modifications 1 and 2. FIG. 4 is a flow chart of a method for manufacturing an electrode plate according to Embodiments 1 and 2 and Modifications 1 and 2. FIG. FIG. 2 is an explanatory diagram schematically showing active material composite particles produced in a mixed powder producing step according to Embodiments 1 and 2 and Modified Embodiments 1 and 2; FIG. 4 is an explanatory diagram of a sheet-like green compact formed in a sheet forming step of the granulated powder production step, according to Embodiments 1 and 2 and Modified Embodiments 1 and 2; FIG. 4 is an explanatory diagram schematically showing crushed particles formed in a crushing step of the granulated powder production step according to Embodiments 1 and 2 and Modified Embodiments 1 and 2; FIG. 5 is an explanatory diagram of sizing particles formed in a sizing step of the granulated powder production step, according to Embodiments 1 and 2 and Modifications 1 and 2; FIG. 5 is an explanatory diagram of classified particles formed in a classification step of the granulated powder preparation step, according to Embodiments 1 and 2 and Modified Embodiments 1 and 2; FIG. 2 is an explanatory diagram of an active material layer forming apparatus according to Embodiment 1 and Modification 1; FIG. 4 is an explanatory diagram schematically showing how active material granulated particles fly from a roll surface toward a current collector foil in a film formation region according to Embodiment 1 and Modified Embodiment 1; FIG. 10 is an explanatory diagram of an active material layer forming apparatus according to Embodiment 2 and Modified Embodiment 2; FIG. 10 is an explanatory diagram schematically showing how active material granulated particles fly from the belt surface toward the current collector foil in the film formation region, according to the second embodiment and the modified example 2;

(Embodiment 1)
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a perspective view of an electrode plate 1 according to the first embodiment. In the following description, the longitudinal direction EH, width direction FH, and thickness direction GH of the electrode plate 1 are defined as the directions shown in FIG. Specifically, the electrode plate 1 is flatly wound to manufacture a rectangular and sealed lithium-ion secondary battery to be mounted on a vehicle such as a hybrid car, a plug-in hybrid car, an electric car, or the like. It is a strip-shaped negative electrode plate used for manufacturing a mold or laminated electrode assembly.

The electrode plate (negative electrode plate) 1 has a strip-shaped collector foil 3 made of copper foil extending in the longitudinal direction EH. A first active material layer 5 (hereinafter also simply referred to as "active material layer 5") is formed on a region extending in the longitudinal direction EH at the center in the width direction FH of the first main surface 3a of the current collector foil 3. is formed in a strip shape. Further, a second active material layer 6 (hereinafter simply referred to as "active material layer 6 ”) is formed in a strip shape. At both ends of the electrode plate 1 in the width direction FH, the active material layers 5 and 6 do not exist in the thickness direction GH, and the collector foil 3 is exposed in the thickness direction GH to form an exposed portion 1r.

Active material layers 5 and 6 are each composed of active material particles 11 and binder 13 . The weight ratio of the active material particles 11 and the binder 13 is active material particles:binder=97.5:2.5. In Embodiment 1, the active material particles 11 are negative electrode active material particles capable of intercalating and deintercalating lithium ions, specifically graphite particles. Further, the binder 13 is polyvinylidene fluoride (PVDF).

Next, a method for manufacturing the electrode plate 1 will be described (see FIGS. 2 to 9). First, in the “mixed powder preparation step S1” (see FIG. 2), active material composite powder 22 composed of active material composite particles 21 in which binder particles 13P are attached to active material particles 11 is prepared (see FIG. 3). . Specifically, active material powder 12 in which active material particles 11 (graphite particles in Embodiment 1) aggregate and binder powder in which binder particles 13P (PVDF particles in Embodiment 1) aggregate 14 is prepared. Then, the active material powder 12 and the binder powder 14 were put into a mixer (not shown) at a weight ratio of active material powder:binder powder=97.5:2.5 and mixed for 1 minute. Stir to mix. As a result, an active material composite powder 22 having a particle size DA ₅₀ (median diameter) of DA ₅₀ =approximately 10 μm is obtained. .

Next, in the “granulated powder preparation step S2” (see FIG. 2), the active material composite powder 22 in which the active material composite particles 21 are aggregated, the active material composite particles 21 are bonded to each other to form an active material. An active material granulated powder 42 in which grains 41 are aggregated is produced (see FIGS. 4 to 7). The granulated powder production step S2 has a sheet forming step S21, a crushing step S22, a granule sizing step S23 and a classifying step S24 in this order.
First, in the "sheet forming step S21", the active material composite powder 22 spread into a flat plate is pressed in the thickness direction to obtain a sheet-like green compact 30 (see FIG. 4). Specifically, the strip-shaped sheet-like green compact 30 is formed by roll-pressing the active material composite powder 22 using a pair of press rolls (not shown).
Next, in the "crushing step S22", the sheet-like compact 30 is crushed to obtain crushed powder 32 in which crushed particles 31 are aggregated (see FIG. 5). Specifically, the sheet-like green compact 30 is crushed with a stirring blade (not shown) to form a crushed powder 32 _composed of crushed particles 31 and having a grain size DB ₅₀ (median diameter) of about 3 mm. .

Next, in the "sizing step S23", the crushed powder 32 is sieved to obtain a sizing powder 34 in which sizing particles 33 are aggregated (see FIG. 6). Specifically, the crushed powder 32 is placed on a wire mesh (not shown) of 20 mesh (opening of 800 μm), and the crushed powder 32 is stirred with a wing (not shown) to pass through the wire mesh. As a result, the regulated powder 34 within the predetermined particle size range PR1 (in the first embodiment, the median diameter D is in the range of 130 to 170 μm), specifically, the particle size DC ₅₀ (median diameter) is _{DC 50 =} A regulated powder 34 of about 150 μm is obtained. The regulated powder 34 contains regulated particles 33 of various sizes, from regulated particles 33 smaller than 50 μm in diameter to large sized particles 33 exceeding 450 μm in diameter.

Next, in the "classifying step S24", the sized powder 34 is classified to obtain the classified powder 36 in which the desired classified particles 35 are aggregated (see FIG. 7). Specifically, a multistage sieve (not shown) having 425 μm, 212 μm, 100 μm and 53 μm sieves is used to divide the sized powder 34 into five size groups. Then, the classified powder 36 mainly composed of the classified particles 35 having a particle size of 100 μm to 212 μm, which passed through the 212 μm sieve and remained on the 100 μm sieve, is recovered. As a result, the classified powder 36 within the predetermined particle size range PR2 (in the first embodiment, the median diameter D ₅₀ is in the range of 130 to 170 μm), specifically, the particle size DD ₅₀ (median diameter) is DD ₅₀ =about A classified powder 36 of 150 μm is obtained. In the first embodiment, the classified powder 36 composed of the classified particles 35 is used as the active material granulated powder 42 composed of the active material granulated particles 41 in the following steps. The repose angle θ of this active material granulated powder 42 is θ≦40.0 (deg), specifically θ=35.8 deg. The repose angle θ is measured by the method described above. In this embodiment, the repose angle θ was measured using a powder tester manufactured by Hosokawa Micron Corporation.

Next, in the “first supply step S3” (see FIG. 2), the above-described active material granulated powder 42 is deposited and shaped into a layer having a uniform thickness, and supplied to the film formation region MR1. This first supply step S3 and the first uncompressed layer forming step S4 and first pressing step S5, which will be described later, are continuously performed using the active material layer forming apparatus 200 (see FIGS. 8 and 9). The active material layer forming apparatus 200 includes a layer forming unit 203 that forms an uncompressed active material layer 5X on the current collector foil 3, and a heat press on the uncompressed active material layer 5X and the current collector foil 3 to form an uncompressed layer. and a pressing part 205 for forming the active material layer 5 from the active material layer 5X.

Among these, the layer forming unit 203 includes a hopper 210, a supply roll 220 arranged below the hopper 210, a backup roll 230 arranged parallel to the supply roll 220 and conveying the current collector foil 3 in the longitudinal direction EH, It has a DC power supply 240 electrically connected to the supply roll 220 and the backup roll 230 .
Of these, the hopper 210 temporarily accommodates the granulated active material powder 42 introduced into the hopper 210 , discharges the granulated active material powder 42 from a lower discharge port, and Place on surface 220m.

The supply roll 220 is configured to be rotatable clockwise in FIGS. 8 and 9 by a motor (not shown) connected thereto, and the rotation of the supply roll 220 causes the hopper 210 to move from the hopper 210 onto the roll surface 220m. The arranged active material granulated powder 42 is conveyed toward the gap KB (film formation region MR1) between the supply roll 220 and the current collector foil 3 . A roll-shaped squeegee 225 is arranged in parallel with the supply roll 220 with a roll gap KC in the vicinity of the upper right of the supply roll 220 in FIG. The squeegee 225 is rotatable in the same direction as the supply roll 220 (clockwise in FIG. 8) by a motor (not shown) connected thereto. This squeegee 225 smoothes the granulated active material powder 42 on the roll surface 220 m, deposits and shapes the granulated active material powder 42 into a layer having a uniform thickness, and forms a deposited layer 43 of the granulated active material powder 42 . to form

The backup roll 230 is arranged in parallel and horizontally with respect to the supply roll 220 (to the right in FIGS. 8 and 9) with a roll gap KA therebetween. The backup roll 230 is rotated in the same direction as the supply roll 220 (clockwise in FIGS. 8 and 9) by a motor (not shown) connected thereto. The second main surface 3b of the collector foil 3 supplied to the layer forming unit 203 of 200 is brought into contact with the wound collector foil 3 and conveyed in the longitudinal direction EH toward the press unit 205 described later.

The DC power supply 240 has its positive electrode electrically connected to the backup roll 230 and its negative electrode electrically connected to the supply roll 220, and the backup roll 230 is grounded. The DC power supply 240 applies a DC voltage Vd1=-2 kV between the supply roll 220 and the backup roll 230 in the first embodiment. Specifically, with the backup roll 230 as a reference (0 V), the potential of the supply roll 220 is -2 kV. As a result, an electrostatic force Fs1 is applied to the active material granulated particles 41 forming the active material granulated powder 42 on the supply roll 220 , and the active material granulated particles 41 fly from the roll surface 220 m toward the current collector foil 3 . .

The press section 205 of the active material layer forming apparatus 200 has a pair of press rolls 271 and 272 arranged in parallel with a roll gap KD therebetween. These press rolls 271 and 272 are configured to be able to heat-press the collector foil 3 and the uncompressed active material layer 5X transported from the layer forming section 203 in the roll gap KD.

Next, the first supply step S3, the first uncompressed layer forming step S4, and the first pressing step S5 (see FIG. 2) performed using the active material layer forming apparatus 200 described above will be described (see FIGS. 8 and 9). ). First, in the "first supply step S3", the active material granulated powder 42 is deposited and shaped into a layer having a uniform thickness to form a deposited layer 43 of the active material granulated powder 42, which is deposited in the film formation region MR1. supply. Specifically, active material granulated powder 42 supplied downward from hopper 210 is placed on roll surface 220 m of supply roll 220 . The active material granulated powder 42 on the roll surface 220m is flattened by the squeegee 225 on the way to the film forming region MR1 due to the rotation of the supply roll 220, and deposited and shaped into a layer of uniform thickness. Further, the deposited layer 43 of the active material granulated powder 42 is conveyed to the film formation region MR1 as the supply roll 220 rotates.

In the subsequent “first uncompressed layer forming step S4”, the active material granulated particles 41 are collected from the roll surface 220m by the DC voltage Vd1 applied between the supply roll 220 and the current collector foil 3 in the film formation region MR1. The active material granulated particles 41 are deposited on the current collector foil 3 by flying toward the electric foil 3 to form the uncompressed active material layer 5X. As a result, an uncompressed active material layer 5X in which the active material granulated particles 41 are deposited on the first main surface 3a of the current collector foil 3 is continuously formed. In the first embodiment, the highly fluid active material granulated powder 42 having the repose angle θ≦40.0 (deg), specifically, the repose angle θ=35.8 deg, is supplied to the film formation region MR1. Therefore, the active material granulated particles 41 forming the active material granulated powder 42 do not aggregate with each other, and the active material granulated particles 41 easily fly individually and accumulate efficiently to form the uncompressed active material layer 5X. It is formed.

Subsequently, in the "first pressing step S5", the uncompressed active material layer 5X and the current collector foil 3 are hot-pressed to form the active material layer 5 from the uncompressed active material layer 5X. Specifically, the current collector foil 3 on which the uncompressed active material layer 5X is formed is conveyed from the layer forming section 203 to the press section 205 and is hot-pressed by the pair of press rolls 271 and 272 of the press section 205 . As a result, the binder particles 13P contained in the uncompressed active material layer 5X are once melted, and the active material particles 11 and the current collector foil 3 are bound to each other through the binder 13. . Thus, the active material layer 5 composed of the active material particles 11 and the binder 13 is continuously formed on the collector foil 3 . The electrode plate having the active material layer 5 on the collector foil 3 is also referred to as "one-sided electrode plate 1Y".

Next, for the one-side electrode plate 1Y described above, a “second supply step S6” (see FIG. 2) similar to the first supply step S3 and a “second uncompressed layer formation step S4” similar to the first uncompressed layer formation step S4 are performed. Compressed layer forming step S7” is performed to form a second uncompressed active material layer 6X (hereinafter also simply referred to as “uncompressed active material layer 6X”) on the second main surface 3b of the current collector foil 3 . That is, first, in the second supply step S6, the active material granulated powder 42 is deposited and shaped into a layer having a uniform thickness, and supplied to the film formation region MR1. Subsequently, in the second uncompressed layer forming step S7, in the film forming region MR1, the active material granulated particles 41 are blown toward the current collector foil 3 to deposit the active material granulated particles 41 on the current collector foil 3. to form an uncompressed active material layer 6X. After that, the “second pressing step S8” (see FIG. 2) similar to the first pressing step S5 described above is performed. That is, the second uncompressed active material layer 6X, the current collector foil 3, and the first active material layer 5 are hot-pressed to form the second active material layer 6 from the second uncompressed active material layer 6X. Thus, the electrode plate 1 shown in FIG. 1 is manufactured.

(Modified form 1)
Next, Modification 1 of Embodiment 1 will be described. In Embodiment 1, manufacturing of the electrode plate 1, which is the negative electrode plate, has been described.

The electrode plate (positive electrode plate) 101 of Modified Embodiment 1 has basically the same shape as the electrode plate (negative electrode plate) 1 of Embodiment 1. FIG. That is, the electrode plate 101 has a current collector foil 103 made of a strip-shaped aluminum foil, and a first active material layer 105 (hereinafter simply referred to as "active material layer 105") is formed on a first main surface 103a of the current collector foil 103. ) is formed in a strip shape, and a second active material layer 106 (hereinafter also simply referred to as “active material layer 106”) is formed in a strip shape on the second main surface 103b on the opposite side of the current collector foil 103. there is Both ends of the electrode plate 101 in the width direction FH are exposed portions 101r.

Active material layers 105 and 106 are composed of active material particles 111, binder 113, and conductive particles 115, respectively. The weight ratio of the active material particles 111, the binder 113, and the conductive particles 115 is active material particles:binder:conductive particles=90:5:5. In Modification 1, the active material particles 111 are positive electrode active material particles capable of intercalating and deintercalating lithium ions, specifically lithium-transition metal composite oxide particles, specifically lithium-nickel-cobalt-manganese composite oxide particles. . Further, the binder 113 is PVDF, like the binder 13 of the first embodiment. Also, the conductive particles 115 are acetylene black (AB) particles.

This electrode plate 101 is also manufactured in substantially the same manner as the electrode plate 1 of the first embodiment. That is, first, in the “mixed powder preparation step S101”, active material powder 112 made of active material particles 111 (lithium-nickel-cobalt-manganese composite oxide particles in this modification 1) and binder particles 113P (this modification 1, a binder powder 114 made of PVDF particles) and a conductive powder 116 made of conductive particles 115 (AB particles) are used, and the rest is mixed in the same manner as in the mixed powder preparation step S1 of Embodiment 1. Then, an active material composite powder 122 composed of the active material composite particles 121 in which the binder particles 113P and the conductive particles 115 are attached to the active material particles 111 is produced (see FIG. 3).

Next, in the "sheet forming step S121" of the "granulated powder preparation step S102", the active material composite powder 122 is pressed to obtain a sheet-like compact 130 (see FIG. 4). Thereafter, in the "crushing step S122", the sheet-like green compact 130 is crushed to obtain crushed powder 132 in which crushed particles 131 are aggregated (see FIG. 5).

After that, in the "sizing step S123", the crushed powder 132 is sieved to obtain a sizing powder 134 in which the sizing particles 133 are aggregated (see FIG. 6). Specifically, in the same manner as in the sizing step S23 of Embodiment 1, the sizing powder 134 within a predetermined particle size range PR1 (in the present modification 1, the median diameter D ₅₀ is in the range of 130 to 170 μm), Specifically, a regulated powder 134 having a particle size DC ₅₀ (median diameter) of DC ₅₀ =about 150 μm is formed.

Next, in a "classifying step S124", the sized powder 134 is classified to obtain a classified powder 136 in which desired classified particles 135 are aggregated (see FIG. 7). Specifically, in the same manner as in the sizing step S23 of the first embodiment, the classified powder 136 within the predetermined particle size range PR2 (in the first modification, the _median diameter D is in the range of 130 to 170 μm), Specifically, a classified powder 136 having a particle size DD ₅₀ (median diameter) of DD ₅₀ =approximately 150 μm is obtained. The classified powder 136 composed of the classified particles 135 is used in subsequent steps as the active material granulated powder 142 composed of the active material granulated particles 141 . The repose angle θ of this active material granulated powder 142 is θ≦40.0 (deg), specifically θ=36.9 deg.

Next, in the "first supply step S103", the active material granulated powder 142 is deposited and shaped into a layer having a uniform thickness to form a deposited layer 143 of the active material granulated powder 142, which is placed in the film formation region. Feed MR1.
Subsequently, in the "first uncompressed layer forming step S104", the active material granulated particles 141 are blown toward the current collector foil 103 in the film formation region MR1, and the active material granulated particles 141 are formed on the current collector foil 103. Deposit to form uncompressed active material layer 105X. In the present modification 1 as well, the highly fluid active material granulated powder 142 having the angle of repose θ≦40.0 (deg), specifically the angle of repose θ=36.9 deg, is supplied to the film formation region MR1. Therefore, the active material granulated particles 141 forming the active material granulated powder 142 do not aggregate, and the active material granulated particles 141 easily fly individually and efficiently accumulate to form the uncompressed active material layer 105X. It is formed.
After that, in the "first pressing step S105", the uncompressed active material layer 105X and the current collector foil 103 are hot-pressed to form the active material layer 105 from the uncompressed active material layer 105X, thereby fabricating the one-sided electrode plate 101Y. .

Next, in the “second supply step S106”, the active material granulated powder 142 is deposited and shaped into a layer having a uniform thickness, and is supplied to the film formation region MR1. Subsequently, in the "first uncompressed layer forming step S107", the active material granulated particles 141 are blown toward the current collector foil 103 in the film formation region MR1, and the active material granulated particles 141 are formed on the current collector foil 103. Deposit to form uncompressed active material layer 106X. After that, in the “second pressing step S108”, the uncompressed active material layer 106X, the current collector foil 103, and the active material layer 105 are hot-pressed to form the active material layer 106 from the uncompressed active material layer 106X, and the electrode plate 101 is made.

(Embodiment 2 and Modification 2)
Next, Embodiment 2 and its Modification 2 will be described. In Embodiment 1 and Modification 1, in manufacturing the electrode plate (negative electrode plate) 1 or the electrode plate (positive electrode plate) 101, the supply roll 220 of the active material layer forming apparatus 200 (see FIGS. 8 and 9) is used to Active material granulated powders 42 and 142 were supplied to the film formation region MR1. On the other hand, in Embodiment 2 and Modified Embodiment 2, when manufacturing the electrode plate (negative electrode plate) 1 or the electrode plate (positive electrode plate) 101, the belt type supply of the active material layer forming apparatus 300 (see FIGS. 10 and 11) is performed. The difference is that the device 320 is used to supply the active material granulated powders 42 and 142 to the film formation region MR2.

This active material layer forming apparatus 300 includes a layer forming section 303 for forming uncompressed active material layers 5X and 105X on current collector foils 3 and 103, and a pressing section 205 similar to the active material layer forming apparatus 200 of the first embodiment. and Of these, the layer forming section 303 has a hopper 310, a backup roll 330, a DC power supply 340 similar to the hopper 210, the backup roll 230, and the DC power supply 240 of the first embodiment, and a belt-type supply device 320 instead of the supply roll 220. .

On the other hand, the belt-type supply device 320 feeds the active material granulated powders 42 and 142 supplied onto the belt surface 321m of the supply belt 321 from the hopper 310 to the current collecting foil conveyed by the supply belt 321 and the backup roll 330. 3 and 103 to the gap KF (film formation region MR2). Specifically, the supply belt 321 is stretched over a pair of transport rolls 322 and 323 . Due to the rotation of the transport rolls 322 and 323, the upper portion of the supply belt 321 advances rightward in FIG.

A first oscillator 325 and a second oscillator 326 are arranged near the supply belt 321 . The first vibrator 325 vibrates the granulated active material powders 42 and 142 supplied from the hopper 310 onto the belt surface 321m from below the supply belt 321, thereby vibrating the granulated active material powders 42 and 142. The active material granulated powders 42 and 142 are evenly deposited and shaped into a layer having a uniform thickness to form deposited layers 43 and 143 of the active material granulated powders 42 and 142 .
On the other hand, the second vibrator 326 is arranged below the film formation region MR2, and vibrates the deposited layers 43, 143 of the active material granulated powders 42, 142 on the belt surface 321m from below the supply belt 321. , the active material granulated particles 41 and 141 forming the deposited layers 43 and 143 are made easier to fly upward toward the current collector foils 3 and 103 in the film formation region MR2.

Next, a method for manufacturing the electrode plates 1 and 101 according to Embodiment 2 and Modification 2 will be described. Also in the second embodiment and the second modification, the mixed powder preparation steps S1 and S101 and the granulated powder preparation steps S2 and S102 are performed in the same manner as in the first embodiment and the first modification. Thereafter, each step after the first supply step S3, S103 is performed using the active material layer forming apparatus 300 described above.

In the first supply steps S3 and S103, the active material granulated powders 42 and 142 are deposited and shaped into layers having a uniform thickness to form deposited layers 43 and 143 of the active material granulated powders 42 and 142, thereby forming a film. supply to region MR2. Specifically, the active material granulated powders 42 and 142 supplied downward from the hopper 310 are placed on the belt surface 321 m of the supply belt 321 . The active material granulated powder 42, 142 on the belt surface 321m is conveyed rightward in FIGS. The active material granulated powders 42 and 142 are deposited and shaped into layers 43 and 143 of a uniform thickness by the vibration caused by the vibration, and the deposited layers 43 and 143 of the active material granulated powders 42 and 142 are transported to the film forming region MR2.

Subsequently, in first uncompressed layer forming steps S4 and S104, DC voltage Vd2 (in Embodiment 2 and Modification 2, Vd2=−2 kV), the active material granulated particles 41, 141 are blown from the belt surface 321m toward the current collector foil 3, 103, and the active material granulated particles 41, 141 are deposited on the current collector foil 3, 103. to form uncompressed active material layers 5X and 105X. Also in Embodiment 2 and Modified Embodiment 2, the highly fluid active material granulated powders 42 and 142 having a repose angle θ≦40.0 (deg) are supplied to the film forming region MR2. Granulated active material particles 41 and 141 forming powders 42 and 142 do not agglomerate, and granulated active material particles 41 and 141 easily fly individually and efficiently accumulate to form uncompressed active material layers 5X and 105X. is formed.

Subsequently, in the first pressing steps S5 and S105, the uncompressed active material layers 5X and 105X and the current collector foils 3 and 103 are hot-pressed in the press section 205 to obtain uncompressed Active material layers 5 and 105 are formed from active material layers 5X and 105X, and one-side electrode plates 1Y and 101Y are produced.

Next, second supply steps S6 and S106 similar to the first supply steps S3 and S103 and first uncompressed layer formation steps S4 and S104 are performed on the one-side electrode plates 1Y and 101Y using the active material layer forming apparatus 300. Second uncompressed layer forming steps S7 and S107 similar to , are performed to form second uncompressed active material layers 6X and 106X on current collector foils 3 and 103, respectively. Furthermore, second pressing steps S8 and S108 similar to the first pressing steps S5 and S105 are performed to form the second active material layers 6 and 106 from the second uncompressed active material layers 6X and 106X, and the electrode plates (negative electrodes plate) 1 or an electrode plate (positive electrode plate) 101 is produced.

(Experimental result)
Next, the results of experiments conducted to verify the effects of the present invention will be described. First, in the manufacture of the electrode plate (negative electrode plate) 1, the angle of repose θ (deg) of the active material powder (the active material composite powder 22 or the active material granulated powder 42) used in the supply step S3 and the uncompressed layer formation In step S4, the relationship between the easiness of flight (flyability) of the active material particles (active material composite particles 21 or active material granulated particles 41) to fly toward the current collector foil 3 was investigated.

As Comparative Example 1, active material composite powder 22 (angle of repose θ = 46.2deg) was used as it was, and the supply step S3 to the press step S5 were carried out in the same manner as in Embodiment 1 except for this to fabricate the one-side electrode plate 1Y.

Next, as Examples 1 to 5, the mixed powder production step S1 to the pressing step S5 were performed in the same manner as in Embodiment 1 except for the method of manufacturing the active material granulated powder 42 used in the supply step S3, and one-sided electrode Plate 1Y was produced respectively. Specifically, in Example 1, the active material granulated powder 42 (angle of repose θ=40. 5deg), the supplying step S3 to the pressing step S5 were performed to fabricate the one-sided electrode plate 1Y.
In Example 2, in the classification step S24, the granulated active material powder 42 (rest The supply step S3 to the press step S5 were performed using the angle θ=36.1 deg).

In Example 3, in the classification step S24, the granulated active material powder 42 (rest The supply step S3 to the press step S5 were performed using the angle θ=35.8 deg).
In Example 4, the active material granulated powder 42 (rest The supply step S3 to the press step S5 were performed using the angle θ=35.3 deg).
In Example 5, the active material granulated powder 42 (angle of repose θ = 34.1 deg) mainly composed of the active material granulated particles 41 having a particle size of more than 425 µm, which remained on the 425 µm sieve in the classification step S24, was collected. The supply step S3 to the press step S5 were carried out using this.

Next, for the electrode plate (positive electrode plate) 101, similarly, one-side electrode plates 101Y of Comparative Example 2 and Examples 6 to 10 were produced. That is, as Comparative Example 2, active material composite powder 122 (angle of repose θ=67.6 deg) was used as it was, and the supply step S103 to the press step S105 were carried out in the same manner as in Modified Embodiment 1 to produce the one-sided electrode plate 101Y.

Further, as Examples 6 to 10, the mixed powder preparation step S101 to the pressing step S105 were performed in the same manner as in Modification 1 except for the method of manufacturing the active material granulated powder 142 used in the supply step S103, and the one-side electrode plate was prepared. 101Y were prepared respectively. Specifically, in Example 6, active material granulated powder 142 (angle of repose θ=50. 4deg), the supplying step S103 to the pressing step S105 were performed to fabricate the one-sided electrode plate 101Y.
Further, in Example 7, active material granulated powder 142 mainly composed of active material granulated particles 141 having a particle size of 53 to 100 μm, which passed through a 100 μm sieve in the classification step S124 but remained on the 53 μm sieve. (Angle of repose θ=39.6 deg) was used to perform the supply step S103 to the press step S105.

In Example 8, active material granulated powder 142 mainly composed of active material granulated particles 141 having a particle size of 100 to 212 μm, which passed through a 212 μm sieve in the classification step S124 but remained on the 100 μm sieve. (Angle of repose θ=35.8 deg) was used to perform the supply step S103 to the press step S105.
In Example 9, active material granulated powder 142 mainly composed of active material granulated particles 141 having a particle size of 212 to 425 μm, which passed through a 425 μm sieve in the classification step S124 but remained on the 212 μm sieve. (Angle of repose θ=35.3 deg) was used to perform the supply step S103 to the press step S105.
In Example 10, active material granulated powder 142 (angle of repose θ = 34.1 deg ) was used to perform the supply step S103 to the press step S105.

As a result, in Comparative Examples 1 and 2, the active material composite particles 21 and 121 hardly flew toward the current collector foils 3 and 103 in the uncompressed layer forming steps S4 and S104 (flying property evaluation in Table 1). "X" marks are shown in the columns). Therefore, the uncompressed active material layers 5X and 105X were hardly formed, and the active material layers 5 and 105 were hardly formed. The active material composite powders 22 and 122 have a larger repose angle θ than the active material granulated powder 142 and have lower fluidity. Such active material composite powders 22 and 122 with low fluidity have a strong cohesive force between particles, so that the active material composite particles 21 and 121 fly toward the current collector foils 3 and 103 in the film formation region MR1. It is thought that there was not.

On the other hand, in Examples 1 to 10, 30% or more of the active material granulated particles 41 and 141 supplied to the film formation region MR1 in the uncompressed layer forming steps S4 and S104 141 flew toward the collector foils 3 and 103 . Therefore, the uncompressed active material layers 5X and 105X were properly formed, and the active material layers 5 and 105 were also properly formed. In particular, in Examples 2 to 5 and 7 to 10, 80% or more of the active material granulated particles 41 and 141 supplied to the film forming region MR1 were deposited on the current collector foils 3 and 103. flew towards it. Therefore, in Examples 2 to 5 and 7 to 10, uncompressed active material layers 5X and 105X with a larger basis weight are formed, and active material layers 5 and 105 with a larger basis weight are formed in Examples 2 to 5 and 7 to 10 than in Examples 1 and 6. rice field. In addition, in the flight performance evaluation column of Table 1, Examples 1 and 5 are marked with "O", and Examples 2 to 5 and 7 to 10 are marked with "◎".

The active material granulated powders 42 and 142 used in Examples 1 to 10 have high fluidity, and the active material granulated particles 41 and 141 are less likely to agglomerate. In particular, the active material granulated powders 42 and 142 used in Examples 2 to 5 and 7 to 10 each have an angle of repose θ of 40.0 deg or less and have high fluidity, and the active material granulated particles 41 and 141 It is particularly difficult to agglomerate. In this way, while the individual granulated active material particles 41 and 141 are separated, they are charged with an appropriate amount of charge according to their size. Active material granulated particles 41 and 141 easily fly individually. As a result, it is considered that many active material granulated particles 41 and 141 were able to fly toward the current collector foils 3 and 103 .
From these results, the supply steps S3, S103 to the pressing steps S5, S105 are preferably performed using the active material granulated powders 42, 142 composed of the active material granulated particles 41, 141. Furthermore, the repose angle It can be seen that it is particularly preferable to use active material granulated powders 42 and 142 satisfying θ≦40.0 (deg).

As described above, in the method for manufacturing the electrode plates 1 and 101, the active material composite particles 21 and 121 in which the binder particles 13P and 113P are attached to the active material particles 11 and 111 are bound to each other by active material granulation. Using the active material granulated powder 42, 142 composed of the particles 41, 141, supply steps S3, S6, S103, S106, uncompressed layer forming steps S4, S7, S104, S107 and pressing steps S5, S8, S105, S108 is performed. Compared to the active material composite particles 21 and 121 having relatively small particle diameters, the active material granulated particles 41 and 141 having relatively large particle diameters due to the bonding of a plurality of active material composite particles 21 and 121 to each other. Cohesion is weak. Therefore, in the uncompressed layer forming steps S4, S7, S104, and S107, the active material granulated particles 41 and 141 can be appropriately caused to fly toward the current collector foils 3 and 103 by the electrostatic forces Fs1 and Fs2. Uncompressed active material layers 5X, 6X, 105X, and 106X can be appropriately formed on the electric foils 3 and 103. Then, the active material layers 5, 6, 105 and 106 can be properly formed.

Further, in the method for manufacturing the electrode plates 1 and 101, in the supply steps S3, S6, S103, and S106, the active material granulated powder having high fluidity, specifically, an angle of repose θ≦40.0 (deg) A body 42, 142 is used. Such highly fluid active material granulated powders 42 and 142 have a particularly weak cohesive force between particles. is more likely to fly toward the current collector foils 3 and 103, the uncompressed active material layers 5X, 6X, 105X, and 106X can be formed more appropriately, and the active material layers 5, 6, 105, and 106 can be formed more appropriately. can be formed to

Further, the method for manufacturing the electrode plates 1 and 101 includes granulated powder production steps S2 and S102 having sheet forming steps S21 and S121, crushing steps S22 and S122, and sizing steps S23 and S123. By performing the granulated powder production steps S2 and S102, the active material granulated powders 42 and 142 having desired fluidity at the angle of repose θ≦40.0 (deg) can be easily produced. Therefore, by using the active material granulated powder 42, 142, the uncompressed active material layers 5X, 6X, 105X, 106X can be formed more appropriately, and the active material layers 5, 6, 105, 106 can be formed more appropriately. can be formed.

In the method of manufacturing the electrode plates 1 and 101, the granulated powder production steps S2 and S102 further include classification steps S24 and S124. Thereby, the active material granulated powders 42 and 142 having more suitable fluidity can be easily produced. Therefore, by using the active material granulated powder 42, 142, the uncompressed active material layers 5X, 6X, 105X, 106X can be formed more appropriately, and the active material layers 5, 6, 105, 106 can be formed more appropriately. can be formed.

In the above, the present invention has been described in accordance with Embodiments 1 and 2 and Modified Embodiments 1 and 2, but the present invention is not limited to Embodiments 1 and 2 and Modified Embodiments 1 and 2. Needless to say, it can be applied with appropriate changes within a range that does not deviate.
For example, in Embodiments 1, 2, etc., supply steps S3, S6, S103, and S106 were performed using the active material granulated powders 42 and 142 obtained by granulation, sizing, and classification. , but not limited to this. The supply steps S3, S6, etc. may be performed using the active material granulated powder obtained without sizing or classification.

1 electrode plate (negative plate)
101 electrode plate (positive electrode plate)
3, 103 current collector foils 5, 105 first active material layers 5X, 105X first uncompressed active material layers 6, 106 second active material layers 6X, 106X second uncompressed active material layers 11, 111 active material particles 12, 112 Active material powders 13, 113 Binders 13P, 113P Binder particles 14, 114 Binder powders 21, 121 Active material composite particles 22, 122 Active material composite powders 30, 130 Sheet-like green compact 31 , 131 Crushed particles 32, 132 Crushed powder 33, 133 Sized particles 34, 134 Sized powder 35, 135 Classified particles 36, 136 Classified powder 41, 141 Active material granulated particles 42, 142 Active material granulated powder Body 43, 143 (active material granulated powder) deposited layers 200, 300 active material layer forming device 210, 310 hopper 220 supply rolls 230, 330 backup rolls 240, 340 DC power supply 320 belt type supply device 321 supply belt DA ₅₀ Median diameter (of active material composite powder) DB ₅₀ Median diameter (of crushed powder) DC ₅₀ (of sizing powder) Median diameter DD ₅₀ (of classified powder) Median diameter PR1 (predetermined of sizing powder) Particle size range PR2 (Predetermined particle size range of classified powder) MR1, MR2 Film forming regions Fs1, Fs2 Electrostatic forces S1, S101 Mixed powder production steps S2, S102 Granulated powder production steps S21, S121 Sheet forming step S22, S122 Crushing steps S23, S123 Grain regulating steps S24, S124 Classification steps S3, S103 First supply steps S4, S104 First uncompressed layer formation steps S5, S105 First press steps S6, S106 Second supply steps S7, S107 Second uncompressed layer forming steps S8, S108 Second pressing step

Claims (4)

A method for manufacturing an electrode plate comprising an active material layer containing active material particles and a binder on a current collector foil, comprising:
The active material granulated powder, in which the active material granulated particles in which the active material composite particles having the binder particles attached to the active material particles are bonded to each other, is deposited and shaped into a layer having a uniform thickness to form a film forming region. a supply step for supplying to
In the film formation region, the active material granulated particles are blown toward the current collector foil by electrostatic force, the active material granulated particles are deposited on the current collector foil, and the uncompressed uncompressed active material an uncompressed layer forming step of forming a layer;
and a pressing step of hot-pressing the uncompressed active material layer and the current collector foil to form the active material layer from the uncompressed active material layer. A method for manufacturing the electrode plate according to claim 1,
The supply step includes
A method for producing an electrode plate using the active material granulated powder having an angle of repose θ≦40.0 (deg). A method for manufacturing the electrode plate according to claim 2,
Prior to the supply step, a granulated powder producing step of producing the active material granulated powder in which the active material granulated particles are aggregated from the active material composite powder in which the active material composite particles are aggregated is further provided. cage,
The granulated powder preparation process includes:
a sheet forming step of pressing the active material composite powder to obtain a sheet-like green compact;
A crushing step of crushing the sheet-like compact to obtain crushed powder;
and a sizing step of sizing the crushed powder to obtain a sizing powder having a particle size within a predetermined particle size range. A method for manufacturing an electrode plate according to claim 3,
The granulated powder preparation step includes:
A method for manufacturing an electrode plate, further comprising a classifying step of classifying the sized powder obtained in the sizing step to obtain a classified powder having a grain size within a predetermined grain size range.

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