Manufacturing apparatus of electrode sheet

Abstract

To more preferably manufacture an electrode sheet.SOLUTION: A manufacturing apparatus 50 of an electrode sheet 35, comprises: a mesh drum 53 that includes a mesh-like peripheral wall 51, and is rotated; and a conveyance device 55 that is synchronized to a rotation of the mesh drum 53, and continuously conveys a current collector foil 31. The manufacturing apparatus 50 comprises: a negative pressure generation device 75 that generates a negative pressure into an inner side of the peripheral wall 51; and an adhesion device 57 that makes an active material powder body 60 to adhere to an outer peripheral surface 51sa of the peripheral wall 51 on the basis of their negative pressure. Then, the manufacturing apparatus 50 is provided with a transportation device 58 that blows an air to an inner peripheral surface 51sb of the peripheral wall 51, and thereby peeling the active material powder body 60 adhering to their outer peripheral surface 51sa, and forms an electrode active material layer 32 by transporting the active material powder body 60 to be peeled onto a surface of the current collector foil 31.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an apparatus for manufacturing an electrode sheet.

Background Art

[0002] Conventionally, for example, in secondary batteries such as lithium-ion secondary batteries, there are those in which positive and negative electrodes are formed using an electrode sheet having an electrode active material layer laminated on the surface of a current collector foil. Further, for example, Patent Document 1 describes a configuration in which an electrode active material agglomerated as a wet powder is sequentially deformed from a plate shape to a strip shape and further to a granular shape. By adopting such a configuration, an electrode active material layer can be stably formed on the surface of the current collector foil serving as the base material of the electrode sheet while reducing the solvent content. As a result, it is possible to shorten the drying time of the electrode active material layer laminated on the surface of the current collector foil while ensuring excellent battery performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the configuration using an electrode active material agglomerated as a wet powder as described above, it is difficult to uniformly disperse additives such as conductive materials and binder materials, for example. Further, in many cases, for the electrode plate of a secondary battery, an electrode sheet having electrode active material layers on both sides of the current collector foil is used. And since the configuration of the above prior art does not include an optimal design of an apparatus for performing such double-sided coating, further improvement has been desired.

Means for Solving the Problems

[0005] Each aspect of an apparatus for manufacturing an electrode sheet for solving the above problems will be described. Aspect 1 includes a mesh drum that rotates and has a mesh-shaped peripheral wall, a conveying device that continuously conveys a current collecting foil in synchronization with the rotation of the mesh drum, a negative pressure generating device that generates a negative pressure inside the peripheral wall, an adhering device that adheres an active material powder to the outer peripheral surface of the peripheral wall based on the negative pressure, and a transfer device that blows air onto the inner peripheral surface of the peripheral wall to peel off the active material powder adhering to the outer peripheral surface and transfers the peeled active material powder onto the surface of the current collecting foil to form an electrode active material layer. The conveying device has a first roll and a second roll around which the current collecting foil is wound at a first opposing position and a second opposing position spaced apart in the circumferential direction of the mesh drum. At the first roll, a first surface of the current collecting foil faces the outer peripheral surface, and at the second roll, a second surface of the current collecting foil faces the outer peripheral surface. The adhering device includes a first adhering portion that adheres the active material powder to the outer peripheral surface of the peripheral wall at a first adhering position spaced upstream in the rotation direction of the mesh drum from the first opposing position, and a second adhering portion that adheres the active material powder to the outer peripheral surface of the peripheral wall at a second adhering position spaced upstream in the rotation direction from the second opposing position. The transfer device includes a first transfer portion and a second transfer portion that transfer the active material powder to the current collecting foil at the first opposing position and the second opposing position.

[0006] According to the above configuration, the active material powder, which is the raw material of the electrode active material layer, can be efficiently laminated on both sides of the current collecting foil. Further, even if the amount of conductive material, binder, etc. contained in the electrode active material layer is small, these additives can be uniformly dispersed. And thereby, the electrode sheet can be manufactured more suitably.

[0007] Aspect 2 is a manufacturing apparatus for an electrode sheet according to Aspect 1, wherein the adhering device includes a solvent spraying portion that sprays a mistified solvent onto the outer peripheral surface of the peripheral wall, and an active material powder input portion that inputs the active material powder into the mistified solvent sprayed onto the outer peripheral surface.

[0008] That is, by introducing the active material powder into the atomized solvent, the active material powder diffuses substantially uniformly in the solvent mist. Therefore, according to the above configuration, the active material powder can be attached to the outer peripheral surface of the peripheral wall with a substantially uniform thickness.

[0009] Aspect 3 is a manufacturing apparatus for an electrode sheet according to Aspect 2, in which the solvent spraying unit sprays a solution of a conductive material as the atomized solvent onto the outer peripheral surface of the peripheral wall. According to the above configuration, since the solvent to be atomized is a solution of a conductive material, the conductive material contained in the solvent mist is in a state of being substantially uniformly dispersed in the solvent mist. As a result, the conductive material can be attached to the active material powder introduced into the solvent mist substantially evenly. As a result, even if the amount of the conductive material contained in the electrode active material layer is small, the conductive material can be homogeneously dispersed in the electrode active material layer.

[0010] Aspect 4 is a manufacturing apparatus for an electrode sheet according to any one of Aspects 1 to 3, which includes a binder applying device that sprays an atomized solution of a binder onto the active material powder during transfer to the current collector foil.

[0011] According to the above configuration, the binder can be attached to the active material powder transferred onto the surface of the current collector foil substantially evenly. As a result, even if the amount of the binder contained in the electrode active material layer is small, the binder can be homogeneously dispersed in the electrode active material layer. Further, the peeling and transfer can be performed more smoothly than in the case where the binder is applied at a stage before the active material powder peels off from the outer peripheral surface of the peripheral wall. And thereby, a stable electrode active material layer can be formed on the surface of the current collector foil.

[0012] Aspect 5 is a manufacturing apparatus for an electrode sheet according to any one of Aspects 1 to 4, which includes a binder applying device that applies a binder to the current collector foil before the active material powder is transferred. According to the above configuration, the binder can be more reliably distributed to the portion that becomes the boundary with the current collector foil. As a result, the electrode active material layer formed by the transferred active material powder can be more strongly bonded to the current collector foil. Furthermore, the peeling and transfer can be performed more smoothly than in the case where the binder is applied at a stage before the active material powder peels off from the outer peripheral surface of the peripheral wall. And thereby, a stable electrode active material layer can be formed on the surface of the current collector foil.

[0013] Aspect 6 is a manufacturing apparatus for an electrode sheet according to any one of Aspects 1 to 5, in which the transfer apparatus blows the air onto the inner peripheral surface of the peripheral wall using the exhaust of the negative pressure generating apparatus. According to the above configuration, simplification of the apparatus can be achieved.

Advantages of the Invention

[0014] According to the present invention, an electrode sheet can be manufactured more suitably.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0016] Hereinafter, an embodiment of a secondary battery will be described with reference to the drawings. (Lithium-ion secondary battery) As shown in FIG. 1, the secondary battery 1 includes an electrode body 10 in which a positive electrode 3, a negative electrode 4, and a separator 5 are integrated, and a case 20 that houses the electrode body 10. The secondary battery 1 of the present embodiment has a configuration as a lithium-ion secondary battery in which the electrode body 10 in the case 20 is impregnated with a non-aqueous electrolyte (not shown).

[0017] Specifically, in the secondary battery 1 of the present embodiment, the positive electrode 3, the negative electrode 4, and the separator 5 have a sheet-like outer shape and are laminated. Then, by winding the laminate of the positive electrode 3, the negative electrode 4, and the separator 5, an electrode body 10 is formed in which the positive and negative electrodes and the separator 5 are alternately arranged in the radial direction with the separator 5 sandwiched between the positive electrode 3 and the negative electrode 4.

[0018] In addition, the case 20 of the present embodiment includes a flat substantially rectangular box-shaped case body 21 and a lid member 22 that closes the opening end 21x of the case body 21. The electrode body 10 of the present embodiment has a flat outer shape corresponding to the box shape of the case 20.

[0019] (Electrode sheet and electrode body) More specifically, as shown in FIG. 2, in the secondary battery 1 of the present embodiment, the positive electrode 3 and the negative electrode 4 each have a configuration as an electrode sheet 35 including a current collector foil 31 having a sheet-like outer shape and an electrode active material layer 32 laminated on the current collector foil 31. Specifically, the electrode sheet 35P for the positive electrode 3 is formed by laminating a positive electrode active material layer 32P containing a lithium transition metal oxide serving as a positive electrode active material on a current collector foil 31P serving as a base material made of aluminum or the like. The electrode sheet 35N for the negative electrode 4 is formed by laminating a negative electrode active material layer 32N containing a carbon-based material serving as a negative electrode active material on a current collector foil 31N serving as a base material made of copper or the like.

[0020] Furthermore, in the secondary battery 1 of the present embodiment, these positive and negative electrode sheets 35P and 35N are each shaped into a strip. And the electrode body 10 of the present embodiment has a configuration as a wound body in which the positive and negative electrode sheets 35P and 35N laminated with the separator 5 interposed therebetween are wound around a winding shaft 10x extending in the width direction of the strip shape (the left-right direction in FIG. 2).

[0021] In FIG. 2, the separator 5 and each electrode sheet 35 are wound in such a manner that the electrode sheet 35P constituting the positive electrode 3 is wound inside. However, this figure is an example showing the structure of the electrode body 10, and there may be a case where the separator 5 and each electrode sheet 35 are wound in such a manner that the electrode sheet 35N constituting the negative electrode 4 is wound inside. And thereby, it is determined whether the electrode sheet 35 disposed on the outermost shell of the electrode body 10 is the electrode sheet 35P constituting the positive electrode 3 or the electrode sheet 35N constituting the negative electrode 4.

[0022] Also, as shown in FIGS. 1 to 3, the lid member 22 of the case 20 is provided with a positive electrode terminal 38P and a negative electrode terminal 38N protruding outside the case 20. Further, each electrode sheet 35 is formed with an uncoated portion 39 on which the electrode active material layer 32 is not formed on the current collector foil 31. And the secondary battery 1 of the present embodiment is configured such that the electrode sheet 35P constituting the positive electrode 3 and the positive electrode terminal 38P are electrically connected using these uncoated portions 39, and the electrode sheet 35N constituting the negative electrode 4 and the negative electrode terminal 38N are electrically connected.

[0023] Specifically, the electrode body 10 of the present embodiment is housed in the case 20 with its winding shaft 10x along the longitudinal direction of the lid member 22 having a long and substantially rectangular plate shape (the left-right direction in FIG. 1). Further, in this state, the uncoated portion 39P of the electrode sheet 35P constituting the positive electrode 3 and the positive electrode terminal 38P are connected via a connecting member 40P. And similarly, the uncoated portion 39N of the electrode sheet 35N constituting the negative electrode 4 and the negative electrode terminal 38N are connected via a connecting member 40N.

[0024] Furthermore, an electrolytic solution 45 is injected into the case 20. That is, for the electrolytic solution 45 of the secondary battery 1 having a configuration as a lithium-ion secondary battery, a solution in which a lithium salt serving as a supporting salt is dissolved in an organic solvent is used. And the secondary battery 1 of the present embodiment is configured such that the electrolytic solution 45 impregnates the electrode body 10 sealed in the case 20 thereby.

[0025] (Manufacturing apparatus for electrode sheet) Next, the configuration of the manufacturing apparatus for the electrode sheet used when manufacturing the secondary battery 1 of the present embodiment will be described.

[0026] As shown in FIG. 4, the manufacturing apparatus 50 used for manufacturing the electrode sheet 35 includes a mesh drum 53 that has a mesh-shaped peripheral wall 51 and rotates. Further, this manufacturing apparatus 50 includes a conveying device 55 that continuously conveys the current collector foil 31 that serves as the base material of the electrode sheet 35 in synchronization with the rotation of the mesh drum 53. Furthermore, in the manufacturing apparatus 50 of the present embodiment, an active material powder 60 that constitutes the electrode active material layer 32 of the electrode sheet 35 is adhered to the peripheral wall 51 of the mesh drum 53. Specifically, the manufacturing apparatus 50 of the present embodiment includes an adhesion device 57 that adheres the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51 from the radially outer side of the mesh drum 53. Further, the manufacturing apparatus 50 includes a transfer device 58 that transfers the active material powder 60 adhered to the peripheral wall 51 of the mesh drum 53 onto the surface of the current collector foil 31 conveyed by the conveying device 55. And the manufacturing apparatus 50 of the present embodiment is configured to continuously form the electrode sheet 35 having the electrode active material layer 32 laminated on the surface of the current collector foil 31 thereby.

[0027] Furthermore, in the secondary battery 1 of the present embodiment, this manufacturing apparatus 50 is used when manufacturing the electrode sheet 35P on the positive electrode 3 side which becomes the positive electrode plate (see FIG. 2). That is, the current collector foil 31 conveyed by the conveying apparatus 55 is the current collector foil 31P for the positive electrode 3 made of a material such as aluminum. And the active material powder 60 attached to the peripheral wall 51 of the mesh drum 53 is a powdery positive electrode active material mainly composed of a lithium transition metal oxide which is a raw material of the positive electrode active material layer 32P formed on the surface of the current collector foil 31 by its transfer.

[0028] More specifically, in the manufacturing apparatus 50 of the present embodiment, the mesh drum 53 has a substantially cylindrical outer shape with the axis of its peripheral wall 51 as the rotation axis. Also, this mesh drum 53 has a plurality of fine through-holes (not shown) penetrating the peripheral wall 51 in the thickness direction over the entire circumference. Incidentally, the mesh shape of the peripheral wall 51 preferably has an aperture diameter of 0.02 mm or less and an opening ratio of 25% or less, and when expressed in terms of the so-called "count", "#635" or more corresponds to this. And the mesh drum 53 of the present embodiment is configured such that the active material powder 60 can be attached to the outer peripheral surface 51sa of its peripheral wall 51.

[0029] Also, the conveying apparatus 55 of the present embodiment includes a plurality of rotators 61 around which the current collector foil 31 is wound. Further, this conveying apparatus 55 includes a pay-out machine 62 and a take-up machine 63 disposed at two positions which are both ends of the conveying path where the current collector foil 31 extends in a strip shape while being wound around these respective rotators 61. And the conveying apparatus 55 of the present embodiment is configured such that the take-up machine 63 winds up the current collector foil 31 fed out from the pay-out machine 62, thereby continuously conveying the current collector foil 31 along the conveying path.

[0030] More specifically, the conveying apparatus 55 of the present embodiment has, as the rotators 61, a first roll 65 and a second roll 66 disposed on the radially outer side of the mesh drum 53 at a first opposed position Pc1 and a second opposed position Pc2 spaced apart in the circumferential direction of the mesh drum 53.

[0031] Specifically, in the transport device 55 of the present embodiment, a first opposing position Pc1 and a second opposing position Pc2 are set at two positions spaced apart from each other by 180 degrees in the circumferential direction of the mesh drum 53. Further, at the first opposing position Pc1, the first surface S1 of the current collecting foil 31 wound around the first roll 65 faces the outer peripheral surface 51sa of the peripheral wall 51 on the radially outer side of the mesh drum 53. And at the second opposing position Pc2, the second surface S2 of the current collecting foil 31 wound around the second roll 66 faces the outer peripheral surface 51sa of the peripheral wall 51 on the radially outer side of the mesh drum 53 as well, having such a configuration.

[0032] Also, in the manufacturing device 50 of the present embodiment, a first attachment position Pa1 is set at a position spaced from the first opposing position Pc1 upstream in the rotation direction of the mesh drum 53 (counterclockwise direction in FIG. 4). And a second attachment position Pa2 is set at a position spaced from the second opposing position Pc2 upstream in the rotation direction of the mesh drum 53 as well.

[0033] Specifically, in the manufacturing device 50 of the present embodiment, the first attachment position Pa1 is set at a position spaced from the first opposing position Pc1 by approximately 90 degrees in the circumferential direction, and the second attachment position Pa2 is set at a position spaced from the second opposing position Pc2 by approximately 90 degrees in the circumferential direction. In other words, these first attachment position Pa1 and second attachment position Pa2 are set at two positions spaced apart by approximately 180 degrees in the circumferential direction that equally sandwich the first opposing position Pc1 downstream in the rotation direction of the mesh drum 53 from the first attachment position Pa1. And these first attachment position Pa1 and second attachment position Pa2 are set at two positions spaced apart by approximately 180 degrees in the circumferential direction that equally sandwich the second opposing position Pc2 downstream in the rotation direction of the mesh drum 53 from the second attachment position Pa2.

[0034] Also, in the manufacturing apparatus 50 of the present embodiment, the adhering device 57 includes a first adhering portion 71 provided at the first adhering position Pa1 and a second adhering portion 72 provided at the second adhering position Pa2. Further, the transfer device 58 includes a first transfer portion 73 provided at the first facing position Pc1 and a second transfer portion 74 provided at the second facing position Pc2. And the manufacturing apparatus 50 of the present embodiment is configured to transfer the active material powder 60 adhered to the peripheral wall 51 of the mesh drum 53 to the first surface S1 and the second surface S2 of the current collector foil 31 continuously conveyed by the conveying device 55, respectively.

[0035] That is, in the manufacturing apparatus 50 of the present embodiment, in the process of continuously conveying the current collector foil 31 fed out from the feeder 62 by the operation of the conveying device 55, the electrode active material layer 32 is efficiently formed on both surfaces of the current collector foil 31 by the above transfer. And the manufacturing apparatus 50 of the present embodiment is configured such that the electrode sheet 35 manufactured thereby is continuously wound up by the winder 63 located at the terminal of the conveying path formed by the conveying device 55.

[0036] More specifically, the manufacturing apparatus 50 of the present embodiment includes a negative pressure generating device 75 that generates a negative pressure inside the cylinder of the mesh drum 53, that is, inside the peripheral wall 51. Specifically, in the manufacturing apparatus 50 of the present embodiment, this negative pressure generating device 75 generates a negative pressure inside the peripheral wall 51 by sucking the air inside the mesh drum 53 by the operation of a suction machine 76 provided outside the mesh drum 53. Further, in the manufacturing apparatus 50 of the present embodiment, by partitioning the inside of the cylinder of the mesh drum 53 with a partition wall (not shown), the air inside the mesh drum 53 is preferentially sucked at the circumferential positions where the first adhering position Pa1 and the second adhering position Pa2 are set. And the manufacturing apparatus 50 of the present embodiment can thereby stably adhere the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51 based on the negative pressure generated inside the peripheral wall 51.

[0037] Also, in the manufacturing apparatus 50 of the present embodiment, the transfer device 58 includes a blower 77 provided outside the mesh drum 53 and an air supply passage 78 routed inside the mesh drum 53. Further, in the transfer device 58 of the present embodiment, the air supply passage 78 has a pair of outlets facing the inner peripheral surface 51sb of the peripheral wall 51 of the mesh drum 53 at circumferential positions where the first facing position Pc1 and the second facing position Pc2 are set, respectively, inside the cylinder of the mesh drum 53. And the transfer device 58 of the present embodiment is configured to have a first transfer portion 73 and a second transfer portion 74 at the first facing position Pc1 and the second facing position Pc2 set around the circumferential direction of the mesh drum 53, respectively.

[0038] That is, in the transfer device 58 of the present embodiment, the blower 77 operates to send air outside the mesh drum 53 into the air supply passage 78. Further, the air pumped through this air supply passage 78 is blown against the inner peripheral surface 51sb of the peripheral wall 51 at the first facing position Pc1 and the second facing position Pc2 where the outlets are provided. And the transfer device 58 of the present embodiment is configured to transfer the active material powder 60 attached to the outer peripheral surface 51sa of the peripheral wall 51 to the first surface S1 and the second surface S2 of the current collector foil 31 facing the radially outer side by peeling it off.

[0039] More specifically, as shown in FIG. 5, the adhesion device 57 of the present embodiment includes a solvent spraying portion 85 that sprays a solvent mist 83 as a mistified solvent against the outer peripheral surface 51sa of the peripheral wall 51 from the radially outer side of the mesh drum 53. The adhesion device 57 also includes an active material powder input portion 86 that inputs the active material powder 60 to the solvent mist 83 sprayed against the outer peripheral surface 51sa of the peripheral wall 51 by the operation of the solvent spraying portion 85. In the adhesion device 57 of the present embodiment, the solvent spraying portion 85 operates by the air pressure of the blower 77 connected via an air supply pipe (not shown). And the active material powder input portion 86 is also configured to input the active material powder 60 in a misty spray state by utilizing the air pressure of the blower 77.

[0040] Furthermore, in the adhesion device 57 of the present embodiment, the first adhesion portion 71 provided at the first adhesion position Pa1 and the second adhesion portion 72 provided at the second adhesion position Pa2 each include these solvent spraying portions 85 and active material powder input portions 86. For convenience of explanation, only the vicinity of the first adhesion position Pa1 is illustrated in FIG. 5. And the adhesion device 57 of the present embodiment is configured to ensure a suitable adhesion state of the active material powder 60 to the peripheral wall 51 of the mesh drum 53 thereby.

[0041] Specifically, in the secondary battery 1 of the present embodiment, as the active material powder 60, for example, a lithium transition metal oxide having a structure in which lithium nickelate, lithium cobaltate, and lithium manganate are combined at a ratio of 1:1:1 is used. Also, for the solvent mist 83, for example, an NMP solvent (N-methyl-pyrrolidone) is used. Further, this solvent mist 83 contains CNT (carbon nanotube) serving as a conductive material. That is, the solvent spraying portion 85 of the present embodiment sprays the solution 84 of the conductive material as the solvent mist 83 onto the peripheral wall 51 of the mesh drum 53. And the adhesion device 57 of the present embodiment is configured to adhere the active material powder 60 in a state where the CNT serving as the conductive material is adhered to the peripheral wall 51 of the mesh drum 53 thereby.

[0042] Note that the active material powder 60 used in the secondary battery 1 of the present embodiment has a particle size of about 5 μm in terms of the median value (D50). Also, the solvent mist 83 is obtained by spraying the NMP solvent with a particle size of about several nm to 50 nm. And the content of CNT in the solution 84 that becomes this solvent mist 83 is set to about 5 wt%, for example.

[0043] That is, by introducing the active material powder 60 into the atomized solvent, the active material powder 60 diffuses substantially uniformly in the solvent mist 83. Further, by using a highly volatile solvent, most of the solvent evaporates before the active material powder 60 sprayed together with the solvent mist 83 reaches the peripheral wall 51 of the mesh drum 53. And the adhesion device 57 of the present embodiment can thereby adhere the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51 with a substantially uniform thickness.

[0044] Furthermore, since the solvent mist 83 is a solution 84 of a conductive material, in the solvent mist 83, the conductive material contained in the solvent mist 83 is in a state of being substantially uniformly dispersed. And the adhesion device 57 of the present embodiment is configured to be able to adhere the conductive material to the active material powder 60 introduced into the solvent mist 83 substantially evenly.

[0045] In addition, the manufacturing apparatus 50 of the present embodiment includes a binder applying device 90 having a nozzle 88 for spraying a misted binder solution 87 onto the active material powder 60 during the transfer to the current collector foil 31 by the transfer device 58.

[0046] Specifically, the binder applying device 90 of the present embodiment is operated by the air pressure of a blower 77 connected via an air supply pipe (not shown). Also, in the secondary battery 1 of the present embodiment, for example, polyvinylidene fluoride (PVdF) is used as the binder, and an NMP solvent is used as the solvent. Further, the content of PVdF in the binder solution 87 is set to about 10 wt%. And the binder applying device 90 of the present embodiment is configured to be able to adhere the binder to the active material powder 60 transferred onto the surface of the current collector foil 31 substantially evenly.

[0047] Furthermore, in the manufacturing apparatus 50 of the present embodiment, the first roll 65 and the second roll 66 provided at the first facing position Pc1 and the second facing position Pc2 respectively have a configuration as heating rolls 91 that apply heat to the current collector foil 31 wound around them. That is, in the manufacturing apparatus 50 of the present embodiment, due to the heating of the current collector foil 31, the solvent of the binder contained in the electrode active material layer 32 formed by the active material powder 60 transferred onto its surface rapidly evaporates. In the secondary battery 1 of the present embodiment, the solid content ratio in the electrode active material layer 32 formed on the current collector foil 31 is set to about 82.7%, for example. And the manufacturing apparatus 50 of the present embodiment is configured to enhance the adhesion force of the electrode active material layer 32 to the current collector foil 31 thereby.

[0048] (Operation) That is, in the manufacturing apparatus 50 of the present embodiment, due to the rotation of the mesh drum 53, the active material powder 60 adhering to the outer peripheral surface 51sa of the peripheral wall 51 moves from the first adhesion positions Pa1 and Pa2 to the first facing position Pc1 and the second facing position Pc2. Further, at these first facing position Pc1 and second facing position Pc2, the active material powder 60 adhering to the outer peripheral surface 51sa of the peripheral wall 51 is transferred to the first surface S1 and the second surface S2 of the current collector foil 31 facing radially outward. And thereby, the electrode active material layer 32 is continuously formed on both surfaces of the current collector foil 31.

[0049] Next, the effects of the present embodiment will be described. (1) The manufacturing apparatus 50 for the electrode sheet 35 includes a mesh drum 53 that has a mesh-shaped peripheral wall 51 and rotates, and a conveying apparatus 55 that continuously conveys the current collector foil 31 in synchronization with the rotation of the mesh drum 53. Further, the manufacturing apparatus 50 includes a negative pressure generating device 75 that generates a negative pressure inside the peripheral wall 51, and an adhering device 57 that adheres the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51 based on the negative pressure. And the manufacturing apparatus 50 includes a transfer device 58 that blows air onto the inner peripheral surface 51sb of the peripheral wall 51 to peel off the active material powder 60 adhering to the outer peripheral surface 51sa thereof, and transfers the peeled active material powder 60 onto the surface of the current collector foil 31 to form the electrode active material layer 32.

[0050] The conveying apparatus 55 has a first roll 65 and a second roll 66 around which the current collector foil 31 is wound at first opposing positions Pc1 and second opposing positions Pc2 spaced apart in the circumferential direction of the mesh drum 53. At the first roll 65, the first surface S1 of the wound current collector foil 31 faces the outer peripheral surface 51sa of the peripheral wall 51. Also, at the second roll 66, the second surface S2 of the wound current collector foil 31 faces the outer peripheral surface 51sa of the peripheral wall 51. The adhering device 57 includes a first adhering portion 71 that adheres the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51 at a first adhering position Pa1 spaced apart from the first opposing position Pc1 upstream in the rotation direction of the mesh drum 53. Further, the adhering device 57 includes a second adhering portion 72 that adheres the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51 at a second adhering position Pa2 spaced apart from the second opposing position Pc2 upstream in the rotation direction of the mesh drum 53. And the transfer device 58 includes a first transfer portion 73 and a second transfer portion 74 that transfer the active material powder 60 adhering to the outer peripheral surface 51sa of the peripheral wall 51 to the current collector foil 31 at the first opposing position Pc1 and the second opposing position Pc2.

[0051] According to the above configuration, the active material powder 60 that is the raw material of the electrode active material layer 32 can be efficiently laminated on both surfaces of the current collector foil 31. Further, even when the amount of the conductive material, binder, etc. contained in the electrode active material layer 32 is small, for example, less than 1 wt%, these additives can be uniformly dispersed. And thereby, the electrode sheet 35 can be manufactured more suitably.

[0052] (2) The adhesion device 57 includes a solvent spraying part 85 that sprays a solvent mist 83, which is a mistified solvent, onto the outer peripheral surface 51sa of the peripheral wall 51. And the adhesion device 57 includes an active material powder input part 86 that inputs the active material powder 60 into the solvent mist 83 sprayed onto the outer peripheral surface 51sa of the peripheral wall 51.

[0053] That is, by inputting the active material powder 60 into the mistified solvent, the active material powder 60 diffuses substantially uniformly in the solvent mist 83. Therefore, according to the above configuration, the active material powder 60 can be adhered to the outer peripheral surface 51sa of the peripheral wall 51 with a substantially uniform thickness.

[0054] (3) The solvent spraying part 85 sprays a solution 84 of a conductive material, which is a mistified solvent, onto the outer peripheral surface 51sa of the peripheral wall 51. According to the above configuration, since the solvent mist 83 is the solution 84 of the conductive material, in the solvent mist 83, the conductive material contained in the solvent mist 83 is in a state of being substantially uniformly dispersed. And thereby, the conductive material can be adhered to the active material powder 60 input into the solvent mist 83 substantially evenly. As a result, even when the amount of the conductive material contained in the electrode active material layer 32 is small, the conductive material can be uniformly dispersed in the electrode active material layer 32.

[0055] (4) The manufacturing device 50 includes a binder applying device 90 that sprays a mistified solution 87 of a binder onto the active material powder 60 on the way of being transferred from the outer peripheral surface 51sa of the peripheral wall 51 to the current collector foil 31.

[0056] According to the above configuration, the binder can be attached to the active material powder 60 transferred onto the surface of the current collector foil 31 substantially evenly. As a result, even if the amount of the binder contained in the electrode active material layer 32 is small, the binder can be homogeneously dispersed in the electrode active material layer 32. Further, the peeling and transfer can be performed more smoothly than in the case where the binder is applied at a stage before the active material powder 60 peels off from the outer peripheral surface 51sa of the peripheral wall 51. And thereby, a stable electrode active material layer 32 can be formed on the surface of the current collector foil 31.

[0057] Note that the above embodiment can be implemented with the following modifications. The above embodiment and the following modification examples can be implemented in combination with each other within a range where there is no technical contradiction.

[0058] ·In the above embodiment, the negative pressure generating device 75 includes a suction machine 76 that sucks air inside the mesh drum 53. And the transfer device 58 is configured to include a blower 77 that sends air outside the mesh drum 53 into the air supply passage 78. However, the present invention is not limited to this, and the configurations of the negative pressure generating device 75 and the transfer device 58 may be arbitrarily changed.

[0059] For example, a configuration may be adopted in which a blower 95 having both of these functions is used instead of the suction machine 76 and the blower 77, as in the manufacturing apparatus 50B of the electrode sheet 35 shown in FIG. 6. That is, in the manufacturing apparatus 50B of this alternative example, the blower 95 sucks air inside the mesh drum 53 in the same manner as the suction machine 76 in the above embodiment. Further, the blower 95 functions in the same manner as the blower 77 in the above embodiment by sending the air sucked from inside the mesh drum 53 into the air supply passage 78. And the manufacturing apparatus 50B of this alternative example is configured such that the transfer device 58 blows air from the inside of the mesh drum 53 onto the inner peripheral surface 51sb of the peripheral wall 51 by using the exhaust of the negative pressure generating device 75. Incidentally, when using the exhaust of the negative pressure generating device 75 in this way, a pressure regulating valve may be provided (not shown). Even if such a configuration is adopted, the same effects as those of the above embodiment can be obtained.

[0060] ·In the above-described embodiment, a binder applying device 90 is provided that sprays a mist of a binder solution 87 onto the active material powder 60 in the process of being transferred from the outer peripheral surface 51sa of the peripheral wall 51 to the current collecting foil 31.

[0061] However, it is not limited to this. For example, like the manufacturing apparatus 50C of the electrode sheet 35 shown in FIG. 7, a binder applying device 97 that applies a binder to the current collecting foil 31 before the active material powder 60 is transferred is provided. Specifically, this binder applying device 97 includes a pair of nozzles 98 provided on the upstream side in the rotation direction of the circumferential direction of the first roll 65 and the second roll 66, respectively, relative to the position facing the mesh drum 53 onto which the active material powder 60 is transferred. And in the manufacturing apparatus 50C of this alternative example, the binder applying device 97 applies a binder to the current collecting foil 31 before transfer using these respective nozzles 98. Incidentally, this binder applying device 97 also sprays the binder solution 99 onto the current collecting foil 31 using the exhaust gas of the negative pressure generating device 75. Even if such a configuration is adopted, the same effects as those of the above-described embodiment can be obtained. In particular, the binder can be more reliably distributed to the portion that becomes the boundary with the current collecting foil. As a result, the electrode active material layer 32 formed by the transferred active material powder 60 can be more strongly bound to the current collecting foil 31.

[0062] ·Furthermore, a configuration in which the binder applying device 90 as in the above-described embodiment and the binder applying device 97 as in this alternative example are used in combination may also be adopted. ·In the above-described embodiment, the solvent spraying section 85 and the active material powder input section 86 of the attaching device 57 are configured to operate by the air pressure of the pressure feeder 77. However, it is not limited to this, and these solvent spraying section 85 and active material powder input section 86 may also be configured to operate using the exhaust gas of the negative pressure generating device 75.

[0063] · Also, in the above-described embodiment, the solvent spraying section 85 of the adhesion device 57 sprays the solvent mist 83, which is a solvent obtained by atomizing the solution 84 of the conductive material, onto the outer peripheral surface 51sa of the peripheral wall 51 from the radially outer side of the mesh drum 53. However, the present invention is not limited to this, and the conductive material addition step may be arbitrarily changed. That is, the solvent spraying section 85 may be configured to spray a solvent not containing a conductive material after atomizing it.

[0064] · Further, the adhesion device 57 does not necessarily have to have the solvent spraying section 85 and the active material powder input section 86. For example, the adhesion device 57 may be configured to directly adhere the active material powder 60 to the outer peripheral surface 51sa of the peripheral wall 51. Even if such a configuration is adopted, the same effects as those of the above-described embodiment can be obtained.

[0065] · Also, if it is possible to stably adhere the active material powder 60 to the peripheral wall 51 of the mesh drum 53, the negative pressure generating device 75 does not necessarily have to be provided. And the transfer device 58 may be configured to perform transfer to the current collector foil 31 by a method other than using air pressure.

[0066] · In the above-described embodiment, the manufacturing device 50 of the electrode sheet 35 is configured to perform so-called double-sided coating on the current collector foil 31. However, the present invention is not limited to this, and it may be applied to a configuration for performing single-sided coating. · In the above-described embodiment, the NMP solvent is used, but the solvent to be used may be arbitrarily changed. Further, the composition of the active material powder 60 may also be arbitrarily changed. And the conductive material and the binder to be added, as well as the content and the like, may also be arbitrarily changed. Note that by using a conductive fibrous carbon material such as CNT as the conductive material, excellent conductivity can be obtained with a small amount. Therefore, by applying such a configuration, a more remarkable effect can be obtained with respect to the dispersibility of the homogeneous additive.

[0067] · Further, in the above embodiment, the manufacturing apparatus 50 was used when manufacturing the electrode sheet 35P on the positive electrode 3 side that becomes the positive electrode plate, but it may also be used when manufacturing the electrode sheet 35N on the negative electrode 4 side that becomes the negative electrode plate.

[0068] · In the above embodiment, the electrode body 10 of the secondary battery 1 was configured as a wound body, but it is not necessarily required that the positive and negative electrode sheets 35P and 35N laminated with the separator 5 in between be wound. That is, the shape of the electrode plate formed using the manufactured electrode sheet 35 is arbitrary. And this secondary battery 1 does not necessarily have to be a lithium ion secondary battery, and it may be applied to other non-aqueous electrolyte secondary batteries.

[0069] · Regarding the terminal shapes of the positive electrode terminal 38P and the negative electrode terminal 38N, they are not limited to the shapes shown in FIG. 1 and may be arbitrarily changed. And regarding the shape of the case 20 that forms the outer shape of the secondary battery 1, it is not necessarily limited to a flat rectangular box shape, and it may be arbitrarily changed, for example, to a cylindrical shape or the like.

[0070] Next, the technical idea that can be grasped from the above embodiment and the modified example will be described. (a) Using the exhaust gas of the negative pressure generating device, the binder applying device sprays the atomized binder solution.

[0071] (b) Using the exhaust gas of the negative pressure generating device, the binder coating device sprays the binder solution onto the current collector foil. (c) Using the exhaust gas of the negative pressure generating device, the solvent spraying section of the adhering device sprays the atomized solvent.

[0072] (2) An electrode sheet manufacturing apparatus comprising: a mesh drum that rotates having a mesh-shaped peripheral wall; a conveying device that continuously conveys a current collector foil in synchronization with the rotation of the mesh drum; an adhering device that adheres an active material powder to the outer peripheral surface of the peripheral wall; and a transfer device that transfers the active material powder adhered to the outer peripheral surface onto the surface of the current collector foil to form an electrode active material layer, wherein the conveying device has a first roll and a second roll around which the current collector foil is wound at first opposing positions and second opposing positions spaced apart in the circumferential direction of the mesh drum, at the first roll, a first surface of the current collector foil faces the outer peripheral surface of the peripheral wall, at the second roll, a second surface of the current collector foil faces the outer peripheral surface of the peripheral wall, and the adhering device includes a first adhering portion that adheres the active material powder to the outer peripheral surface of the peripheral wall at a first adhering position spaced apart from the first opposing position upstream in the rotation direction of the mesh drum, and a second adhering portion that adheres the active material powder to the outer peripheral surface of the peripheral wall at a second adhering position spaced apart from the second opposing position upstream in the rotation direction, and the transfer device includes a first transfer portion and a second transfer portion that transfer the active material powder to the current collector foil at the first opposing position and the second opposing position.

Explanation of Signs

[0073] 31…Current collector foil 32…Electrode active material layer 35…Electrode sheet 50…Manufacturing apparatus 51…Peripheral wall 51sa…Outer peripheral surface 51sb…Inner peripheral surface 55…Conveying device 57…Adhering device 58…Transfer device 60…Active material powder 65…First roll 66…Second roll 71…First adhering portion 72…Second adhering portion 73…First transfer portion 74…Second transfer portion 75…Negative pressure generating device S1…First surface S2…Second surface Pa1…First adhering position Pa2…Second attachment position Pc1…First facing position Pc2…Second facing position

Claims

1. A mesh drum having a mesh-like peripheral wall and rotating; A conveying device that continuously conveys the current collecting foil in synchronization with the rotation of the mesh drum; a negative pressure generating device that generates a negative pressure inside the peripheral wall; an adhesion device that adheres active material powder to the outer peripheral surface of the peripheral wall based on the negative pressure; a transfer device that blows air onto an inner peripheral surface of the peripheral wall to peel off the active material powder adhering to the outer peripheral surface and transfers the peeled active material powder onto a surface of the current collecting foil to form an electrode active material layer, the conveying device has a first roll and a second roll around which the current collecting foil is wound at a first opposing position and a second opposing position spaced apart in a circumferential direction of the mesh drum, In the first roll, a first surface of the current collecting foil faces the outer circumferential surface, In the second roll, a second surface of the current collecting foil faces the outer circumferential surface, The deposition device comprises: a first attachment portion that attaches the active material powder to an outer circumferential surface of the peripheral wall at a first attachment position that is spaced from the first opposing position to the upstream side in a rotation direction of the mesh drum; a second attachment portion that attaches the active material powder to the outer circumferential surface of the peripheral wall at a second attachment position that is spaced from the second opposing position upstream in the rotation direction, The transfer device is an electrode sheet manufacturing apparatus including a first transfer unit and a second transfer unit that transfer the active material powder to the current collector foil at the first opposing position and the second opposing position.

2. The deposition device comprises: a solvent spraying unit that sprays a mist of solvent onto an outer peripheral surface of the peripheral wall; The electrode sheet manufacturing apparatus according to claim 1 , further comprising: an active material powder input section that inputs the active material powder into the mist of the solvent sprayed onto the outer peripheral surface.

3. The electrode sheet manufacturing apparatus according to claim 2 , wherein the solvent spraying unit sprays a solution of a conductive material as the mist of solvent onto the outer peripheral surface of the peripheral wall.

4. The electrode sheet manufacturing apparatus according to claim 1 , further comprising a binder applying device that sprays a mist of a binder solution onto the active material powder in the middle of being transferred to the current collecting foil.

5. The electrode sheet manufacturing apparatus according to claim 1 , further comprising a binder application device that applies a binder to the current collector foil before the active material powder is transferred.

6. 6. The electrode sheet manufacturing apparatus according to claim 1, wherein the transfer device blows the air onto the inner circumferential surface of the peripheral wall by using exhaust from the negative pressure generating device.

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