JP2014154380A - Electrode roll and method for manufacturing electrode roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode roll capable of preventing an active material layer from being damaged, and to provide a method for manufacturing the electrode roll.SOLUTION: In an electrode roll 10 in which respective strip electrodes 12, 13 having an active material layer 16 on both surfaces of a strip metal foil 15 are wound, a coated portion 16a in which the metal foil 15 is covered with the active material layer 16 along a longitudinal direction Y1 and an uncoated portion 16b in which the metal foil 15 is not covered with the active material layer 16 are alternately arranged in the respective strip electrodes 12, 13, and the coated portion 16a in a first layer of the respective wound strip electrodes 12, 13 entirely overlaps on the uncoated portion 16b in the other layer adjacent to the first layer at the outside of a radial direction Y2 when viewing from the radial direction Y2.

Description

  The present invention relates to an electrode roll obtained by winding a strip electrode and a method for manufacturing the electrode roll.

  Conventionally, lithium ion secondary batteries, nickel-hydrogen secondary batteries, and the like are well known as power storage devices mounted on vehicles such as EVs (Electric Vehicles) and PHVs (Plug-in Hybrid Vehicles). And in such an electrical storage apparatus, the strip | belt-shaped electrode which has on both surfaces the active material layer formed by apply | coating the active material paste containing an active material on the surface of strip | belt-shaped metal foil is used.

  And in the manufacturing process of an electrical storage apparatus, while winding a strip | belt-shaped electrode into a roll shape and making it an electrode roll, it is preserve | saved with this electrode roll, or performing a heating (baking) process (for example, patent) Reference 1).

  In Patent Document 1, the belt-like electrode is wound while being shifted in the axial direction of the winding axis, thereby suppressing contact between the end height portions formed at the edge of the active material layer in the axial direction. . Thereby, in the electrode roll of patent document 1, the deformation | transformation of the electrode resulting from the end high parts of an active material layer contacting is suppressed.

International Publication No. 2006/120906

  However, in the electrode roll of Patent Document 1, since the active material layers are in contact with each other, the active material layers may rub against each other due to vibration during transportation, and the active material layer may be damaged.

  This invention was made paying attention to the problem which exists in the said prior art, The objective is to provide the manufacturing method of the electrode roll which can suppress that an active material layer breaks, and an electrode roll. is there.

  An electrode roll that solves the above problem is an electrode roll obtained by winding a band-shaped electrode having active material layers on both sides of a band-shaped metal foil. The band-shaped electrode includes the metal foil along a longitudinal direction. The first region covered with the active material layer and the second region where the metal foil is not covered with the active material layer are alternately arranged, and the first region in the first layer of the band-shaped electrode wound The gist is that, when viewed from the radial direction, the whole overlaps the second region in the second layer adjacent to the first layer and the outer side in the radial direction.

  According to this configuration, the first region of the belt-like electrode in the first layer in the electrode roll is the second region in the second layer, the entirety of which is adjacent to the first layer in the radial direction when viewed from the radial direction. Active material layers do not contact each other. For this reason, it can suppress that an active material layer breaks.

  In the electrode roll, the first region in one strip electrode and the second region in the other strip electrode were wound in opposition to each other. According to this structure, it can suppress simply that active material layers contact between one strip electrode and another strip electrode.

In the electrode roll, a single strip-shaped electrode was wound. According to this configuration, since a single strip electrode is wound, an electrode roll can be easily formed.
In the electrode roll, an end portion in the axial direction of the winding shaft has an annular recess that is recessed in the axial direction along the winding direction of the strip electrode. According to this configuration, the end in the axial direction of the winding shaft has an annular recess that is recessed in the axial direction along the winding direction of the belt-like electrode, so that the end is flat compared to the case where the end is flat. Thus, the surface area can be increased, and for example, the efficiency of heating and cooling in the heat treatment can be improved.

  The said electrode roll WHEREIN: The said recessed part is provided in the said radial direction, the 1st inclined surface which inclines with respect to the said radial direction, and the radially outer side of the said 1st inclined surface is provided in the said radial direction The angle at which the first inclined surface and the second inclined surface intersect is 90 ° or more and 100 ° or less.

  According to this configuration, the angle at which the first inclined surface of the concave portion and the second inclined surface provided on the radially outer side of the first inclined surface intersect is 90 ° or more and 100 ° or less. It can suppress that the radiant heat from a surface is absorbed by the other inclined surface. Therefore, for example, the cooling efficiency in the heat treatment can be improved.

  An electrode roll manufacturing method that solves the above problem is a method of manufacturing an electrode roll in which a band electrode having active material layers on both sides of a band-shaped metal foil is wound. A first region in which the metal foil is covered with an active material layer and a second region in which the metal foil is not covered with an active material layer are alternately arranged along a direction, and the first region of the strip electrode is arranged. The gist is to wind the belt-like electrode so that the entire first region in the layer overlaps with the second region in the second layer adjacent to the first layer in the radial direction when viewed from the radial direction. And

  According to this configuration, the first region in the first layer overlaps with the second region in the second layer adjacent to the first layer and the outer side in the radial direction when viewed from the radial direction. Material layers do not contact each other. For this reason, it can suppress that an active material layer breaks.

  According to the present invention, the active material layer can be prevented from being damaged.

The perspective view which shows an electrode roll typically. FIG. 1 is a sectional view taken along line 1-1 shown in FIG. (A) is sectional drawing which expands and shows an electrode roll typically, (b) is sectional drawing which expands and schematically shows the edge of an active material layer.

Hereinafter, an embodiment of the electrode roll will be described.
As shown in FIGS. 1 and 2, the electrode roll 10 has an electrode laminate 14 in which a first strip electrode 12 and a second strip electrode 13 are superimposed on a cylindrical or columnar core 11. It is wound around the winding axis L a plurality of times. The core material 11 is made of metal such as stainless steel.

  In this embodiment, since the first strip electrode 12 and the second strip electrode 13 have the same configuration, the first strip electrode 12 will be described in detail, and the description of the second strip electrode 13 is the same. Omitted by adding a symbol.

  As shown in FIG. 1, the first strip electrode 12 has a plurality of active material layers 16 at equal intervals along the longitudinal direction Y <b> 1 of the metal foil 15 on both surfaces of the strip-shaped metal foil 15. Each active material layer 16 has a rectangular shape when viewed from a direction orthogonal to the surface of the metal foil 15. Further, each active material layer 16 provided on one surface of the metal foil 15 has an active material layer 16 provided on the other surface of the metal foil 15 when viewed from a direction orthogonal to the surface of the metal foil 15. And overlap each other. Each active material layer 16 is formed by intermittently applying an active material paste containing an active material, a conductive agent, a binder, and a solvent to both surfaces of the metal foil 15.

  Here, the metal foil 15 of the strip-like electrodes 12 and 13 for the positive electrode is, for example, an aluminum foil, and an active material for the positive electrode is used as the active material. Moreover, the metal foil 15 of the strip electrodes 12 and 13 for the negative electrode is, for example, a copper foil, and an active material for the negative electrode is used as the active material.

  In the present embodiment, the region where the metal foil 15 is covered with the active material layer 16 is the coating portion 16a as the first region, and the region where the metal foil 15 is not covered with the active material layer 16 is the second region. It becomes the uncoated part 16b. That is, in the first strip electrode 12, the coated portions 16a and the uncoated portions 16b are alternately arranged along the longitudinal direction Y1. Note that the metal foil 15 is exposed in the uncoated portion 16b.

  The length L1 of the coated part 16a along the longitudinal direction Y1 is shorter than the length L2 of the uncoated part 16b along the longitudinal direction Y1. That is, the length L1 of the active material layer 16 along the longitudinal direction Y1 is shorter than the spacing between the active material layers 16 along the longitudinal direction Y1.

  In the electrode laminate 14, the coating portion 16 a of the first strip electrode 12 is entirely uncoated with the second strip electrode 13 when viewed from the direction perpendicular to the surfaces of the strip electrodes 12 and 13. It overlaps with the part 16b. That is, in the electrode laminate 14, each coated portion 16a in one of the strip electrodes 12 and 13 is opposed to each uncoated portion 16b of the other strip electrode.

  And the electrode laminated body 14 is wound with respect to the core material 11 in the state which has arrange | positioned the 2nd strip | belt-shaped electrode 13 inside the radial direction Y2 in the electrode roll 10. FIG. Thus, in the electrode roll 10, the coating part 16a in the 1st strip | belt-shaped electrode 12 which comprises the electrode laminated body 14, and the uncoated part 16b in the 2nd strip | belt-shaped electrode 13 are each wound by facing.

  Moreover, as shown in FIG. 3, in the electrode roll 10, the uncoated part 16b in the 1st strip | belt-shaped electrode 12 of the electrode laminated body 14 when the whole is on the outer side of radial direction Y2, when it sees from radial direction Y2. It overlaps and is in contact with the coating portion 16a in the second strip electrode 13 of the adjacent electrode laminate 14. That is, the coating portion 16a in the first strip electrode 12 of the electrode laminate 14 is entirely in the second strip electrode 13 of the electrode laminate 14 adjacent to the outside in the radial direction Y2 when viewed from the radial direction Y2. It overlaps and is in contact with the uncoated portion 16b.

  For this reason, in the electrode roll 10 of this embodiment, the coating part 16a in the predetermined layer (first layer) of each of the strip electrodes 12 and 13 has a diameter that is the same as that of the predetermined layer when viewed from the radial direction Y2. It overlaps and is in contact with the uncoated portion 16b in the other layer (second layer) adjacent to the outside in the direction Y2. That is, the coating part 16a in each layer of the strip electrodes 12 and 13 is opposed to the uncoated part 16b in the other layer except for the outermost layer and the innermost layer of the electrode roll 10.

  As shown in FIGS. 1 and 2, both end portions 10 a and 10 b of the electrode roll 10 in the axial direction Y <b> 3 of the winding axis L are in the winding direction (circumferential direction) of the strip electrodes 12 and 13. A plurality of recesses 21 having an annular shape (substantially annular shape) recessed along the axial direction Y3 is provided. In the present embodiment, two (double) recesses 21 are provided, and each recess 21 is concentrically arranged at the end portions 10a and 10b of the electrode roll 10 when viewed from the axial direction Y3. ing.

  As shown in FIG. 2, each recess 21 is provided inside the radial direction Y2 and is inclined in the radial direction Y2, and is provided outside the radial direction Y2, in the radial direction Y2, and It has the 2nd inclined surface 21b inclined in the opposite direction to the 1st inclined surface 21a. Each of the recesses 21 has an inverted isosceles triangle shape with the cross-sectional shape when cut along a plane along the winding axis L as a vertex at the intersection of the first inclined surface 21a and the second inclined surface 21b. .

  The inclined surfaces 21a and 21b are formed by arranging the edge portions 14a of the layers of the strip electrodes 12 and 13 so as to be shifted in a fine step shape along the axial direction Y3. Moreover, in the electrode roll 10 of this embodiment, angle (theta) which the 1st inclined surface 21a and the 2nd inclined surface 21b in each recessed part 21 cross is 90 degrees or more and 100 degrees or less, for example.

  Here, as shown in FIG. 3A, each recess 21 is provided by winding the electrode laminate 14 (each strip-like electrode 12, 13) periodically shifted along the axial direction Y3. ing. More specifically, in the electrode roll 10, the amount of shift per turn for shifting the edge portion 14 a of the electrode laminate 14 in the axial direction Y 3 is, for example, when each strip-shaped electrode 12, 13 for negative electrode is wound, The thickness is set to 80 μm or more, which is 12 or 13 or more.

  Further, the amount of shift of the electrode laminate 14 is set to, for example, 200 μm or more which is equal to or greater than the thickness of each of the strip electrodes 12 and 13 when winding the strip electrodes 12 and 13 for the positive electrode. Further, the shift amount of the electrode laminate 14 is set to be less than 2 mm. In addition, it grasps | ascertains that both edge part 10a, 10b of the electrode roll 10 has the some convex part which is the annular | circular shape (substantially annular shape) which protrudes in the axial direction Y3 by the recessed part 21 adjacent to radial direction Y2. You can also.

Next, the operation of the electrode roll 10 will be described.
As shown in FIG. 3 (a), in the electrode roll 10, the coating portion 16a in each layer of the strip electrodes 12, 13 is entirely adjacent to the outside of the radial direction Y2 when viewed from the radial direction Y2. It overlaps with the uncoated part 16b in the layer. That is, in the electrode roll 10, the active material layer 16 and the metal foil 15 on which the active material layer 16 is not formed overlap and contact, while the active material layers 16 do not contact each other.

  For this reason, for example, the active material layers 16 are rubbed together with the application of vibration during the conveyance of the electrode roll 10 and the expansion and contraction of the metal foil 15 due to the heating (baking) process. Can be prevented from being crushed or peeled off from the metal foil 15.

  In particular, as shown in FIG. 3B, an end height portion 16c is often formed at the edge of the active material layer 16 in the width direction of each strip electrode 12, 13, and the end height portion 16c. It is possible to suppress the active material layer 16 from being partially pulverized or peeled off from the metal foil 15 due to the local concentration of stress due to contact with each other.

  Moreover, as shown in FIG. 3, in the electrode roll 10, the electrode laminated body 14 which overlap | superposed each strip | belt-shaped electrode 12 and 13 in the state which made the coating part 16a and the uncoated part 16b each oppose is wound. Yes. For this reason, it can suppress easily that the active material layers 16 contact between the 1st strip | belt-shaped electrode 12 and the 2nd strip | belt-shaped electrode 13 which comprise the electrode laminated body 14 at least.

  Further, as shown in FIG. 2, both end portions 10a and 10b of the electrode roll 10 in the axial direction Y3 have annular recesses 21 that are recessed in the axial direction Y3. The surface area can be increased compared to the case where 10b is flat.

  In the electrode roll 10, the angle θ between the first inclined surface 21 a and the second inclined surface 21 b in each recess 21 is 90 ° or more and 100 ° or less. For this reason, for example, when the electrode roll 10 is cooled after being heat-treated, the radiant heat from one of the inclined surfaces 21a and 21b (arrow Y4) as in the case where the angle θ is less than 90 ° (arrow Y4). However, it can suppress that it is obstruct | occluded by the other inclined surface.

Next, a method for manufacturing the electrode roll 10 will be described focusing on the winding method of the strip electrodes 12 and 13.
First, an active material paste obtained by kneading an active material, a conductive agent, a binder, and a solvent is intermittently applied to the strip-shaped metal foil 15 along the longitudinal direction Y1 (application process). Next, the active material paste applied to the metal foil 15 is dried (drying step). Next, the dried active material paste is roll-pressed to form an active material layer 16 to obtain the strip electrodes 12 and 13 (pressing process).

  Next, the first strip electrode 12 and the second strip electrode 13 are stacked in a state where the coated portion 16a of one strip electrode and the uncoated portion 16b of the other strip electrode are opposed to each other. The body 14 is obtained (lamination process).

  Subsequently, the electrode stack 14 is wound a predetermined number of times (for example, 20 times) while being shifted to one side in the axial direction Y3 by the above-described shift amount, and then is predetermined while being shifted to the other side in the axial direction Y3. Repeat winding (for example, 20 times) (winding step). Thereby, the recessed part 21 is formed concentrically in both edge part 10a, 10b of the electrode roll 10, respectively.

  Further, in the winding step, when the coating portion 16a in the predetermined layer (first layer) of each of the strip electrodes 12 and 13 is viewed from the radial direction Y2, the whole is outside the predetermined layer and the radial direction Y2. It winds so that it may overlap with the uncoated part 16b in an adjacent other layer (2nd layer). Thereafter, the electrode roll 10 is heated (baked) at a predetermined temperature.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) In the electrode roll 10, each coating part 16a overlaps with the uncoated part 16b, respectively, when viewed from the radial direction Y2. That is, in the electrode roll 10, since the active material layers 16 are not in contact with each other, damage due to the contact between the active material layers 16 can be suppressed.

  (2) In the electrode roll 10, the electrode laminated body 14 which overlap | superposed each strip | belt-shaped electrodes 12 and 13 is wound in the state which made the coating part 16a and the uncoated part 16b each oppose. For this reason, it can suppress simply that the active material layers 16 contact between the 1st strip | belt-shaped electrode 12 and the 2nd strip | belt-shaped electrode 13 which comprise the electrode laminated body 14 at least.

  (3) Since the end portions 10a and 10b of the electrode roll 10 in the axial direction Y3 have an annular recess 21 that is recessed along the winding direction of the strip electrodes 12 and 13 and in the axial direction Y3, The surface area can be increased compared to the case where the end portions 10a and 10b are flat. Therefore, for example, when the heat treatment of the electrode roll 10 is performed, the efficiency of heating and cooling can be improved.

  (4) Moreover, the removal of the residual solvent in the active material layer 16 by heat treatment can be promoted by providing the recesses 21 at the end portions 10a and 10b of the electrode roll 10. That is, the time required for the heat treatment can be shortened.

  (5) The angle θ between the inclined surfaces 21a and 21b is 90 ° or more and 100 ° or less. For this reason, for example, when the electrode roll 10 is cooled after being heat-treated, the radiant heat from one of the inclined surfaces 21a and 21b is prevented from being blocked by the other inclined surface, thereby For example, the cooling efficiency after the heat treatment can be improved.

  (6) Each recessed part 21 is provided by winding the electrode laminated body 14 periodically shifted along the axial direction Y3 of the winding axis L. For this reason, each recessed part 21 can be provided in the electrode roll 10 simply.

  (7) In the electrode roll 10, the edge 14 a of the electrode laminate 14 (the strip electrodes 12 and 13) is intentionally shifted, so that the stress caused by the thermal contraction of the active material layer 16 due to the heat treatment is released. It is possible to reduce the occurrence of wrinkles in the metal foil 15.

The embodiment is not limited to the above, and may be embodied as follows, for example.
In each strip electrode 12, 13, a formation region formed by bringing a plurality of active material layers 16 (coating portions 16a) close to each other along the longitudinal direction Y1 and a length exceeding the length of the formation region in the longitudinal direction Y1 The uncoated portions 16b may be alternately arranged.

  (Circle) the electrode roll 10 may have the single 1st strip | belt-shaped electrode 12 wound. However, even in this case, when each coated portion 16a is viewed from the radial direction Y2, it is wound so as to overlap with the uncoated portion 16b in the other layer. According to this configuration, the electrode roll 10 can be easily formed.

The electrode laminate 14 may be formed by laminating three or more strip electrodes in a state where the coated portion 16a in one strip electrode and the uncoated portion 16b in another strip electrode are opposed to each other.
The first strip electrode 12 and the second strip electrode 13 may be laminated simultaneously while being wound around the core material 11. Even in the case of such a configuration, it is possible to easily suppress contact between the active material layers 16 between one strip electrode and another strip electrode.

The electrode roll 10 may omit the core material 11.
(Circle) the recessed part 21 may be provided 1 or 3 or more.
The angle θ at which the inclined surfaces 21a and 21b intersect may be less than 90 °. However, from the viewpoint of efficiently releasing radiant heat when the electrode roll 10 is cooled, it is preferable to configure as in the above embodiment. Further, the angle θ at which the inclined surfaces 21a and 21b intersect may exceed 100 °. However, from the viewpoint of increasing the surface area of the electrode roll 10 and improving the cooling efficiency, it is preferable to configure as in the above embodiment.

  The end portions 10 a and 10 b of the electrode roll 10 may have an annular flat portion between the concave portions 21. That is, the portion sandwiched between the recesses 21 may have a trapezoidal shape in which each cross section when cut along a plane along the winding axis L protrudes outward in the axial direction Y3. Moreover, each recessed part 21 may be reverse semicircle shape where each cross section at the time of cut | disconnecting in the plane along the winding axis | shaft L is dented in the axial direction Y3. That is, each inclined surface 21a, 21b may be curved.

Each recess 21 may have a different period for shifting the edge 14 a of the electrode stack 14. That is, the respective recesses 21 may have different sizes and may have different angles θ.
Each strip electrode 12, 13 may have a ceramic coat layer that covers the active material layer 16. Even in this case, the ceramic coat layer in the electrode roll 10 can be prevented from being damaged.

O You may embody in the electrode for electrical storage apparatuses, such as a nickel metal hydride secondary battery and an electric double layer capacitor.
O You may actualize in the electrode for electrical storage apparatuses used other than a vehicle.

  θ ... angle, L ... winding axis, Y1 ... longitudinal direction, Y2 ... radial direction, Y3 ... axial direction, 10 ... electrode roll, 10a, 10b ... end, 12 ... first strip electrode, 13 ... second strip electrode , 14 ... Electrode laminate, 15 ... Metal foil, 16 ... Active material layer, 16a ... Coated part (first region), 16b ... Uncoated part (second region), 21 ... Recess, 21a ... First slope Surface, 21b ... 2nd inclined surface.

Claims (6)

An electrode roll obtained by winding a band-shaped electrode having an active material layer on both sides of a band-shaped metal foil,
In the strip electrode, first regions in which the metal foil is covered with an active material layer and second regions in which the metal foil is not covered with an active material layer are alternately arranged along the longitudinal direction. ,
The first region in the first layer of the wound strip-shaped electrode is overlapped with the second region in the second layer adjacent to the first layer in the radial direction when viewed from the radial direction. A featured electrode roll.   2. The electrode roll according to claim 1, wherein a first region in one strip electrode and a second region in another strip electrode are wound in opposition to each other.   The electrode roll according to claim 1, wherein the single band-like electrode is wound.   The electrode roll according to any one of claims 1 to 3, wherein an end portion of the winding shaft in the axial direction has an annular recess that is recessed along the winding direction of the belt-like electrode and in the axial direction. The concave portion is provided on the inner side in the radial direction and is inclined with respect to the radial direction, and the second inclined surface is provided on the outer side in the radial direction of the first inclined surface and is inclined in the radial direction. And
The electrode roll according to claim 4, wherein an angle between the first inclined surface and the second inclined surface is 90 ° or more and 100 ° or less. A method for producing an electrode roll obtained by winding a strip electrode having an active material layer on both sides of a strip metal foil,
In the strip electrode, first regions in which the metal foil is covered with an active material layer and second regions in which the metal foil is not covered with an active material layer are alternately arranged along the longitudinal direction. ,
When the entire first region in the first layer of the strip electrode is viewed from the radial direction, the strip electrode is overlapped with the second region in the second layer adjacent to the first layer on the outside in the radial direction. A method for producing an electrode roll, comprising winding.