JP2013251201A - Power storage element, electrode body, winding method, and winding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element which includes an electrode body composed of a cathode and an anode plate and two sheets of separators which are alternately laminated, and which can prevent the cathode and the anode plates from getting shorted.SOLUTION: The power storage element includes an electrode body 120 composed of a cathode plate 122 and an anode plate 123 and a first separator 124 and a second separator 125, the first separator 124 and the second separator 125 being disposed between the cathode plate 122 and the anode plate 123, in which composition the cathode plate 122 and the anode plate 123 and the first separator 124 and the second separator 125 are laminated in a plurality of layers. The first separator 124 and the second separator 125 each have folds L1 in the vicinity of edges thereof.

Description

  The present invention relates to a positive electrode plate, a negative electrode plate, and two separators that are alternately stacked to form an electrode body, a power storage device having the electrode body, and a winding method and a winding device for manufacturing the electrode body.

  Conventionally, a storage element including a battery such as a lithium ion battery has an electrode body in which a positive electrode, a negative electrode, and a separator are stacked. In order to maintain the insulation between the positive electrode and the negative electrode even when the storage element is placed in a high temperature environment, a separator in which a heat-resistant layer such as a heat-resistant filler is applied to the separator constituting the electrode body has been devised. (See Patent Document 1).

JP 2011-90917 A

  However, since such a heat-resistant coated separator has a two-layer structure in which a heat-resistant layer is coated on a base material layer, it tends to bend due to a temperature change due to a difference in thermal expansion coefficient between these layers. For this reason, twisting and folding due to rounding are likely to occur at the beginning of winding of the innermost circumference, especially during winding, and when such twisting or folding occurs in the separator, the positive and negative electrodes may be short-circuited. Even in the case of a single-layer separator that is not a multi-layer separator such as a heat-resistant coating separator, folding may occur in the separator during winding.

  Therefore, the present invention has been made in view of such a situation, and in a power storage element having an electrode body in which a positive electrode plate and a negative electrode plate and two separators are alternately stacked, a short circuit between the positive electrode and the negative electrode. It is an object of the present invention to provide a power storage element that can prevent the occurrence of water.

  In order to achieve the above object, a power storage device according to an aspect of the present invention includes a positive electrode and a negative electrode, and a separator, and the separator includes an electrode body disposed between the positive electrode and the negative electrode. The separator has a fold at its end.

  According to this, it has a fold in the edge part vicinity of a separator. Thus, by providing a fold in the vicinity of the end of the separator, a surface along the two directions from the vicinity of the fold is formed, so when laminating a plurality of layers of the positive electrode and the negative electrode and the separator, It is possible to prevent the separator from being twisted or folded. For this reason, it can prevent manufacturing the electrical storage element which has an electrode body in the state where the positive electrode and the negative electrode were short-circuited.

  The electrode body is formed by winding in a state where the positive electrode and the negative electrode and the two separators are laminated, and the fold line is on the side where the two separators start to be wound. You may form in the range from the edge part to the position away from predetermined length.

  According to this, the crease formed in at least one of the two separators is formed within a predetermined length from the end portion on the side where winding starts. That is, the crease is provided in a region other than between the positive electrode and the negative electrode of the separator. Thus, since the crease is provided at a position that does not affect the positive electrode and the negative electrode, it is possible to prevent the separator from being twisted or folded without substantially affecting the performance of the electrode body.

  The electrode body is formed by winding in a state where the positive electrode and the negative electrode and the two separators are laminated, and the fold line is formed along the winding direction of the electrode body. It may be formed over the entire separator.

  According to this, for example, a surface parallel to the rotation direction of the roll that protrudes outward in the radial direction and has a V-shaped cross section is formed along the direction in which the crease is formed. A crease can be formed over the entire separator along the winding direction of the electrode body by pressing the roll against the separator in a proper direction and feeding the separator with the roll. That is, by providing the roll in a part of the winding device or in the middle of the transport line, it is possible to form a fold line in the entire winding direction of the separator. For this reason, it is not necessary to provide a new manufacturing process line, and it can be easily realized at low cost.

  The electrode body is formed by winding in a state where the positive electrode and the negative electrode and the two separators are laminated, and an active material is applied to the surfaces of the positive electrode and the negative electrode. The fold may be formed at a position facing at least one of the positive electrode and the negative electrode.

  According to this, the crease formed in at least one of the two separators is formed at a position facing the uncoated region. Since the uncoated area hardly affects the performance of the electrode body, providing a crease at a position facing the uncoated area hardly affects the performance of the electrode body. It is possible to prevent twisting and folding.

  The fold line may be formed at both ends of the electrode body in the winding axis direction.

  According to this, the fold formed in at least one of the two separators is formed at both ends in the winding axis direction of the electrode body. By providing creases at both ends in the winding axis direction, the occurrence of twisting and folding of the separator can be further prevented.

  The fold line may be formed along a winding direction of the electrode body.

  The separator may include a first layer and a second layer made of a material different from that of the first layer.

  According to this, since a plurality of layers are made of different materials, the separators have different coefficients of thermal expansion. For this reason, bending is likely to occur due to temperature changes. Even in such a separator, a crease is formed in the vicinity of the end portion of the separator, so that the separator is prevented from being twisted or folded particularly when a plurality of layers of the positive electrode, the negative electrode, and the separator are laminated. Can do.

  Note that the present invention can be realized not only as such a power storage element but also as an electrode body constituting such a power storage element. In addition, it can be realized as a winding method and a winding device for manufacturing a power storage element or an electrode body.

  According to the electricity storage device of the present invention, it is possible to make it difficult for the separator to be twisted or folded, and it is possible to prevent the electricity storage device having an electrode body in a state where the positive electrode and the negative electrode are short-circuited.

FIG. 3 is a perspective view schematically showing the inside of the battery with a part of the wall portion of the container of the electricity storage device of Embodiment 1 of the present invention omitted. It is a perspective view which shows typically the external appearance of an electrode body. It is III-III sectional drawing of the electrode body of FIG. It is a figure which shows the structure before winding of an electrode body. It is VV sectional drawing of the separator of FIG. It is a figure which shows a winding apparatus. It is a VII-VII sectional view of the indenter of FIG. It is the schematic which looked at the conveyance roll provided in a part of conveyance line of a 1st separator and a 2nd separator from the side of the conveyance direction. It is IX-IX sectional drawing of the conveyance roll 410 shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. The shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are examples, and are not intended to limit the present invention. The invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

  FIG. 1 is a perspective view schematically showing the inside of a battery by omitting a part of a wall portion of a container of a storage element.

  The storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte battery such as a lithium ion secondary battery.

  As shown in the figure, the power storage element 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300, and the container 100 includes a lid plate 110 that is an upper wall. In addition, an electrode body 120, a positive electrode current collector 130, and a negative electrode current collector 140 are disposed inside the container 100.

  Note that a liquid such as an electrolytic solution is sealed inside the container 100 of the power storage element 10, but the liquid is not shown. Moreover, the electrical storage element 10 is not limited to a non-aqueous electrolyte battery, and may be a secondary battery other than the non-aqueous electrolyte battery or a capacitor.

  The container 100 includes a container body having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid plate 110 that closes an opening of the container body. In addition, the container 100 can be hermetically sealed by welding the lid plate 110 and the container body after the electrode body 120 and the like are accommodated therein.

  The electrode body 120 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. Specifically, the electrode body 120 is formed by winding a layered arrangement so that a separator is sandwiched between a negative electrode and a positive electrode so that the whole becomes an oval shape. In addition, in the same figure, although the ellipse shape was shown as a shape of the electrode body 120, circular shape or elliptical shape may be sufficient. The detailed configuration of the electrode body 120 will be described later.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 120, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 120. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 120 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 120, It is an electrode terminal made of metal for introducing. The positive electrode terminal 200 and the negative electrode terminal 300 are attached to the lid plate 110 disposed above the electrode body 120.

  The positive electrode current collector 130 is disposed between the positive electrode of the electrode body 120 and the side wall of the container 100, and is a member having conductivity and rigidity that is electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 120. It is. The positive electrode current collector 130 is made of aluminum or an aluminum alloy, like the positive electrode current collector foil of the electrode body 120.

  The negative electrode current collector 140 is a member that is disposed between the negative electrode of the electrode body 120 and the side wall of the container 100 and has electrical conductivity and rigidity that are electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 120. It is. The negative electrode current collector 140 is made of copper or a copper alloy, like the negative electrode current collector foil of the electrode body 120.

  FIG. 2 is a perspective view schematically showing the appearance of the electrode body. 3 is a cross-sectional view taken along the line III-III of the electrode body of FIG.

  As shown in FIGS. 2 and 3, the electrode body 120 as a wound electrode body includes a winding core 126, a wound body 121, and an insulating sheet 127.

  The winding core 126 is formed by welding and fixing the outermost end of a long belt-shaped winding sheet made of polypropylene or polyethylene, for example, in three, and is formed on the innermost periphery of the wound body 121. Be placed.

  The wound body 121 is disposed between a positive electrode plate 122 as a positive electrode and a negative electrode plate 123 as a negative electrode, and between the positive electrode plate 122 and the negative electrode plate 123, and two separators 124 and 125 and a positive electrode plate 122 are laminated. In the state, it is wound around the core 126 so that the cross section has an oval shape. More specifically, the wound body 121 includes a first separator 124, a negative electrode plate 123, and a second separator 125 stacked in this order, and the first separator 124 and the second separator 125 are attached to the core 126. It is configured by welding and fixing, and winding four sheets of the positive electrode plate 122, the first separator 124, the negative electrode plate 123, and the second separator 125 around the winding core 126 (winding shaft). . That is, the two separators 124 and 125 sandwich the positive electrode plate 122 as the positive electrode, and the second layers 124 b and 125 b forming the second surfaces of the separators 124 and 125 are in contact with the positive electrode plate 122. The two separators 124 and 125 sandwich the negative electrode plate 123 as a negative electrode, and the first layers 124a and 125a forming the first surfaces of the separators 124 and 125 are in contact with the negative electrode plate. The wound body 121 is wound without the positive electrode plate 122 and the negative electrode plate 123 on the outermost periphery (the last round).

  The wound body 121 is wound around the winding core 126 in a state where the positive electrode plate 122 and the negative electrode plate 123 on which the active material is applied and the two separators 124 and 125 are alternately stacked. Become. That is, the wound body 121 is wound so that the cross section has an oval shape in a state where the positive electrode plate 122, the first separator 124, the negative electrode plate 123, and the second separator 125 are stacked in this order. It consists of.

  The positive electrode plate 122 is obtained by forming a positive electrode active material layer on the surface of a long strip-shaped positive electrode current collector foil made of aluminum or an aluminum alloy. In addition, the positive electrode plate 122 used for the electrical storage element 10 according to the present invention is not particularly different from that conventionally used, and a commonly used one can be used.

For example, as the positive electrode active material, polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, etc. , Spinel compounds such as lithium manganate, lithium transition metal oxides such as LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), etc. can be used. .

  The negative electrode plate 123 is obtained by forming a negative electrode active material layer on the surface of a long strip negative electrode current collector foil made of copper or a copper alloy. In addition, the negative electrode plate 123 used in the electricity storage device 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

For example, as the negative electrode active material, a known material can be appropriately used as long as it is a negative electrode active material capable of occluding and releasing lithium ions. For example, lithium metal and lithium alloys (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys) and lithium can be occluded / released. Alloys, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₆ O ₁₂ etc.), polyphosphate compounds Etc.

  The first separator 124 and the second separator 125 are long strip separators disposed between the positive electrode plate 122 and the negative electrode plate 123. The first layer 124a, 125a and the second layer 124b, 125b I have.

  The first layers 124a and 125a are base layers of the first separator 124 and the second separator 125, and are microporous sheets containing a thermoplastic resin.

  Specifically, a resin porous membrane having a woven or non-woven fiber of polymer, natural fiber, hydrocarbon fiber, glass fiber or ceramic fiber is used as the first layers 124a and 125a. The porous resin membrane preferably has woven or non-woven polymer fibers. In particular, the porous resin membrane preferably has a polymer fabric or fleece or is such a fabric or fleece. Preferred examples of the polymer fiber include polyacrylonitrile (PAN), polyamide (PA), polyester, polyethylene terephthalate (PET), and polyolefin (PO). Examples of the polyolefin include polypropylene (PP), polyethylene (PE) or Non-conductive fibers of polymers selected from such polyolefin mixtures. The resin porous membrane may be a polyolefin microporous membrane, a nonwoven fabric, paper or the like, and is preferably a polyolefin microporous membrane. As the porous polyolefin layer, polyethylene, polypropylene, or a composite film thereof can be used. In consideration of the influence on the battery characteristics, the thickness of the first layers 124a and 125a is preferably about 5 to 30 μm.

  The second layers 124b and 125b are layers different in material from the first layers 124a and 125a, which are disposed on the first layers 124a and 125a. In the present embodiment, the second layers 124b and 125b are heat-resistant coating layers coated on the first layers 124a and 125a. Here, the heat resistant coating layer includes, for example, a mixture of inorganic particles and a binder or a heat resistant resin (heat resistant particles).

Specifically, the inorganic particles are composed of one or more of the following inorganic substances alone or as a mixture or a composite compound. For example, iron _{oxide, SiO 2, Al 2 O 3} , TiO 2, BaTiO 2, ZrO, alumina - oxide such as silica composite oxide, aluminum nitride, nitrides particles, calcium fluoride, such as silicon nitride, barium fluoride Slightly soluble ionic crystal particles such as barium sulfate, covalently bonded crystal particles such as silicon and diamond, clay particles such as talc and montmorillonite, boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, sericite, bentonite, Examples of the inorganic substance include substances derived from mineral resources such as mica or artificial products thereof. In addition, the above-mentioned inorganic substance is a material having an electrical insulating property on the surface of conductive fine particles such as oxide fine particles such as SnO ₂ and tin-indium oxide (ITO), and carbonaceous fine particles such as carbon black and graphite (for example, In addition, fine particles imparted with electrical insulation by surface treatment with the above-described material constituting the electrically insulating inorganic particles) may be used.

  The binder is not particularly limited. For example, polyacrylonitrile, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene. Polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene or polycarbonate. In particular, from the viewpoint of electrochemical stability, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene, polyethylene oxide, polyacrylic acid, polymethacrylic acid or styrene-butadiene rubber is preferred.

  Although it does not specifically limit as heat resistant resin, It is a material with a softening point higher than the constituent material of 1st layer 124a, 125a. For example, crosslinked polymers such as polyimide, polyamide, polyamideimide, melamine resin, phenolic resin, crosslinked polymethyl methacrylate (crosslinked PMMA), crosslinked polystyrene (crosslinked PS), polydivinylbenzene (PDVB), benzoguanamine-formaldehyde condensate And heat-resistant polymers such as thermoplastic polyimide. These organic resins (polymers) are a mixture of the above exemplified materials, a modified body, a derivative, a copolymer (random copolymer, alternating copolymer, block copolymer, graft copolymer), crosslinked body ( In the case of the above heat-resistant polymer).

  FIG. 4 is a diagram illustrating a configuration of the electrode body before winding.

  As shown in FIG. 4, in the state before the electrode body 120 is wound, the end portions of the first separator 124 and the second separator 125 are taped to the outer peripheral surface of the core 126 with an adhesive tape 128. ing. And the positive electrode plate 122 and the negative electrode plate 123 are laminated | stacked and arrange | positioned at intervals to the lower side of FIG. 4 from the edge part by which the 1st separator 124 and the 2nd separator 125 are tape-fixed. Further, the positive electrode plate 122 and the negative electrode plate 123 are stacked while being shifted from each other in the width direction of the long belt (winding axis direction) via the first separator 124 and the second separator 125. The positive electrode plate 122 and the negative electrode plate 123 have an uncoated region where the active material is not applied at the edge portions in the respective shifting directions, so that the active material is formed at one end portion of the winding shaft. An aluminum foil as a positive electrode base material is exposed, and a copper foil as a negative electrode base material on which no active material is formed is exposed at the other end of the winding shaft. In this way, the uncoated areas are formed at both ends of the electrode body 120 in the winding axis direction.

  The first separator 124 and the second separator 125 have a crease L1 in the vicinity of their end portions (end portions that are taped). The crease L1 is formed along the winding direction of the electrode body 120 (that is, the longitudinal direction of the first separator 124 and the second separator 125). Further, the crease L1 is formed within a predetermined length from the end of the first separator 124 and the second separator 125 on the side where winding starts. The “predetermined length” referred to here may be, for example, the length of the outer circumference of the core 126 or the length of one circumference of the outer circumference of the core 126. Between the end of the first separator 124 and the second separator 125 on the winding start side to the region where the positive electrode plate 122 and the negative electrode plate 123 start to face each other with the first separator 124 or the second separator 125 interposed therebetween. It may be a distance. From the distance from the end of the first separator 124 and the second separator 125 on the winding start side to the region where the positive electrode plate 122 and the negative electrode plate 123 start to face each other with the first separator 124 or the second separator 125 interposed therebetween However, when the short length is set to the “predetermined length”, the fold line is preferable because it hardly affects the electrode reaction between the positive electrode and the negative electrode.

  FIG. 5 is an enlarged VV sectional view of the vicinity of the fold of the separator of FIG.

  As shown in FIG. 5, in the vicinity of the crease L1 formed in the first separator 124 and the second separator 125, the cross section of the first separator 124 and the second separator 125 is bent in a V shape, and the crease L1. It is in a state that is not folded (no wrapping) starting from. Specifically, the fold line is continuous (or intermittent) along the winding direction where the concave portion or the convex portion can be confirmed by visual observation or inspection with various microscopes such as an optical microscope, a laser microscope, and an electron microscope. Refers to a site that exists for a certain length. Alternatively, when the cross section of the member is viewed, at the position of the crease L1, the distance from the concave surface of the crease L1 is equal to the thickness Δt of the first separator 124 or the second separator 125 (that is, from the crease L1 to the point P1 The distance and the distance from the crease L1 to the point P2 are equal to the thickness Δt of the first separator 124 or the second separator 125.) Two straight lines formed by connecting the same two points P1 and P2 (recess side surface) This refers to a structure in which the formed angle α is an angle sufficiently smaller than 180 degrees (for example, 160 degrees or less).

  FIG. 6 is a diagram illustrating the winding device. 7 is a VII-VII cross-sectional view of the indenter of FIG. As shown in FIG. 6, the winding device 400 includes an upper indenter 401 and a lower indenter 402 as fold forming portions, and a winding portion 404. The upper indenter 401 has recesses 401a having a V-shaped cross section at both ends in the width direction. Further, the lower indenter 402 is formed with convex portions 402a that fit into the concave portions 401a having a V-shaped cross section at both ends in the width direction. The upper indenter 401 is provided with a cutting portion 403 on the downstream side in the flow direction of the first separator 124 and the second separator 125. The winding portion 404 is formed together with the positive electrode plate 122 and the negative electrode plate 123 in a state where the first separator 124 and the second separator 125 taped to the core 126 are sandwiched between the positive electrode plate 122 and the negative electrode plate 123. Winding around the core 126.

  As shown in the upper diagram of FIG. 6, in order to form the electrode body 120, the winding unit 404 is wound in a state where the positive electrode plate 122, the negative electrode plate 123, the first separator 124, and the second separator 125 are stacked. To do. When the winding is finished, the upper indenter 401 and the lower indenter 402 sandwich the first separator 124 and the second separator 125 and apply pressure to form the fold L1 (the middle diagram in FIG. 6). ). Further, the cutting unit 403 cuts the first separator 124 and the second separator 125 in a state where the first separator 124 and the second separator 125 are sandwiched between the upper indenter 401 and the lower indenter 402 (the lower diagram in FIG. 6). As described above, in the state where the fold line L1 is formed in the first separator 124 and the second separator 125 by the upper indenter 401 and the lower indenter 402, the first separator 124 and the second separator 125 flow in the downstream direction from the formed fold line L1. The side is cut. That is, the crease L1 is formed at the beginning of the first separator 124 and the second separator 125 in the flow direction (near the end on the side where winding starts). For this reason, by providing a cutting portion 403 on the downstream side of the first separator 124 and the second separator 125 in the flow direction of the upper indenter 401 and the lower indenter 402, the upper indenter 401 and the lower indenter 402 make the first separator 124 and the second separator While forming the crease L1 in 125, the position where the crease L1 is formed can be formed in the vicinity of the end of the first separator 124 and the second separator 125 on the side where the winding starts.

  According to the electricity storage device 10 according to the above embodiment, the first separator 124 and the second separator 125 have the crease L1 in the vicinity of the end portions. Thus, by providing the fold line L1 in the vicinity of the end portions of the first separator 124 and the second separator 125, surfaces along the two directions from the vicinity of the fold line L1 are formed. When a plurality of layers of the plate 123, the first separator 124, and the second separator 125 are laminated, the first separator 124 and the second separator 125 are less likely to be twisted or folded. For this reason, it can prevent manufacturing the electrical storage element 10 which has the electrode body 120 of the state which the positive electrode plate 122 and the negative electrode plate 123 short-circuited.

  Moreover, according to the electrical storage element 10 according to the above-described embodiment, the first separator 124 and the second separator 125 are made of different materials, and thus have different thermal expansion coefficients. For this reason, bending is likely to occur due to temperature changes. Even in the first separator 124 and the second separator 125, since the crease L1 is formed in the vicinity of the end portions of the first separator 124 and the second separator 125, in particular, the positive electrode plate 122 and the negative electrode plate 123, When multiple layers of the first separator 124 and the second separator 125 are stacked, it is possible to prevent the first separator 124 and the second separator 125 from being twisted or folded.

  Further, according to the electricity storage device 10 according to the above embodiment, the fold line L1 formed in the first separator 124 and the second separator 125 is formed within a predetermined length from the end portion on the side where winding starts. The That is, the crease L1 is provided in a region other than between the positive electrode plate 122 and the negative electrode plate 123 of the first separator 124 and the second separator 125. Further, as shown in FIG. 5, the crease L <b> 1 is uneven in the thickness direction, and therefore the portion where the crease L <b> 1 of the first separator 124 and the second separator 125 is formed is the positive plate 122 and the negative plate 123. Is sandwiched between the positive electrode plate 122 and the negative electrode plate 123 at a position corresponding to the crease L1. For this reason, the position where the crease L1 is formed tends to affect the performance of the electrode body 120. However, since the first separator 124 and the second separator 125 of the electricity storage element 10 are provided with the crease L1 at a position that does not affect the positive electrode plate 122 and the negative electrode plate 123, the performance of the electrode body is hardly affected. In addition, the separator can be prevented from being twisted or folded.

  According to power storage element 10 according to the above embodiment, fold line L1 is formed along the winding direction of electrode body 120 (that is, the longitudinal direction of first separator 124 and second separator 125). In addition to this direction, the first separator 124 or the second separator 125 may be formed obliquely so as to extend toward the corner of the innermost peripheral edge when winding, or in the winding axis direction. Even if it forms so that it may meet, it is effective.

  Further, according to the electricity storage device 10 according to the above embodiment, the first separator 124 and the second separator 125 are taped to the core 126 by the adhesive tape 128 in the vicinity of the center of the long strip-like width direction (winding axis direction). The laminated positive electrode plate 122, negative electrode plate 123, first separator 124, and second separator 125 are wound, but the present invention is not limited to tape fastening, and may be heat-welded to the core 126. . If the end shape of the separator is not stable when performing thermal welding and a curve is generated, there is a risk of thermal welding in a curved state. When wound in such a state, the separator tends to be twisted. However, by providing the crease L1 in the vicinity of the end portions of the first separator 124 and the second separator 125, the shape of the end portion of the separator at the time of heat welding can be stabilized.

  Moreover, according to the electrical storage element 10 according to the above-described embodiment, the position in the winding axis direction of the fold line L1 formed in the first separator 124 and the second separator 125 is not particularly limited, but the uncoated region It is preferable to be formed at a position opposite to. That is, it is preferable that the crease L1 is formed in a range of a predetermined length from the end of the first separator 124 and the second separator 125 on the side where winding starts and facing the uncoated region. . Since the uncoated region is a region that hardly affects the performance of the electrode body 120, by providing the crease L1 at a position facing the uncoated region, the performance of the electrode body 120 is hardly affected. Further, it is possible to prevent the first separator 124 and the second separator 125 from being twisted or folded. In this case, the position facing the uncoated region includes directly facing the uncoated region of the positive electrode plate 122 or the negative electrode plate 123, and any sheet (positive plate 122, negative electrode plate). 123, the first separator 124 or the second separator 125).

  Moreover, according to the electrical storage element 10 according to the above embodiment, the folds L1 formed in the first separator 124 and the second separator 125 are provided at both ends in the winding axis direction, and both the folds L1 are Although it is formed at a position facing both of the uncoated areas at both ends in the winding axis direction, even if only one fold line L1 of the two fold lines L2 is opposed to the uncoated area, Good.

  Moreover, according to the electricity storage device 10 according to the above embodiment, the fold line L1 formed in the first separator 124 and the second separator 125 is the end of the first separator 124 and the second separator 125 on the side where winding starts. However, the present invention is not limited to this, and the first separator 124 and the second separator 125 may be formed along the winding direction of the electrode body 120.

  A manufacturing method in this case will be described below with reference to FIGS.

  FIG. 8 is a schematic view of a transport roll 410 provided in a part of the transport line of the first separator 124 and the second separator 125 as viewed from the side in the transport direction. 9 is a IX-IX cross-sectional view of the transport roll 410 shown in FIG.

  The transport roll 410 includes a fold support roll 411 and a holding roll 412. The transport roll 410 is a device for transporting the first separator 124 and the second separator 125 to a winding device that winds the electrode body 120, and is provided in the winding device as a part of the winding device. Alternatively, it may be provided in the middle of a transport line that transports the first separator 124 and the second separator 125. As shown in FIGS. 8 and 9, the crease support roll 411 has a convex portion 411 a that protrudes outward in the radial direction and has a V-shaped cross section. Further, two fold support rolls 411 are provided for one holding roll 412 and are disposed at positions facing both ends of the first separator 124 and the second separator 125 in the winding axis direction. . Note that the number of holding rolls 412 is not limited to one, and two or more holding rolls 412 may be provided as long as the holding rolls 412 face the two fold support rolls 411.

  In other words, the conveyance roll 410 includes the fold support roll 411 and the holding roll 412 sandwiching the first separator 124 and the second separator 125 in the middle of conveyance, and the convex portion 411a of the fold support roll 411 is inserted into the first separator. 124 and the second separator 125 are pressed against each other in the winding axis direction of the first separator 124 and the second separator 125, and the whole of the first separator 124 and the second separator 125 along the winding direction of the electrode body 120. This is an apparatus for forming the crease L1 over the entire area. In this case, the crease L1 formed in the first separator 124 and the second separator 125 is not preferable because the crease L1 provided in the region contributing to the electrode reaction may adversely affect the electrode reaction. It is preferably formed at a position facing at least one uncoated region of the plate 122 and the negative electrode plate 123. In addition, since the crease L1 is provided at both ends of the first separator 124 and the second separator 125 in the winding axis direction, the first separator 124 can be prevented from being twisted or folded. Furthermore, in this manufacturing method, the fold line L1 is formed by passing the first separator 124 and the second separator 125 between the fold support roll 411 and the holding roll 411, so that the electrode body 120 is wound in the winding direction. The continuous crease L1 can be easily formed. Moreover, since the fold support roll 411 is provided in a part of the winding device or in the middle of the transport line, the folds over the entire winding direction of the first separator 124 and the second separator 125 can be formed. It is not necessary to provide a line for a simple manufacturing process, and can be realized easily at low cost.

  Moreover, according to the electrical storage element 10 according to the above-described embodiment, the electrode body 120 employs a wound electrode body, but is not limited thereto, and may be a stacked electrode body.

  As mentioned above, although the electrical storage element of this invention was demonstrated based on embodiment, this invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to this embodiment, and the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

  The power storage element according to one embodiment of the present invention can be less likely to be twisted or folded into the separator, and is useful as a power storage element having a structure in which a positive electrode and a negative electrode are less likely to be short-circuited.

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Container 110 Cover plate 120 Electrode body 121 Winding body 122 Positive electrode plate 123 Negative electrode plate 124 First separator 124a, 125a First layer 124b, 125b Second layer 125 Second separator 126 Core 127 Insulation sheet 128 Adhesive tape 130 positive electrode current collector 140 negative electrode current collector 200 positive electrode terminal 300 negative electrode terminal 400 winding device 401 upper indenter 401a concave portion 402 lower indenter 402a convex portion 403 cutting portion 404 winding portion 410 conveying roll 411 fold support roll 412 holding roll L1 Creases P1, P2 Point Δt Thickness α Angle

Claims (10)

A positive electrode and a negative electrode, and a separator, the separator comprising an electrode body disposed between the positive electrode and the negative electrode;
The separator has a fold at an end thereof. The electrode body is formed by being wound in a state where the positive electrode and the negative electrode and the two separators are laminated,
The electric storage element according to claim 1, wherein the fold is formed in a range from an end portion of the two separators on the side where winding starts to a position separated by a predetermined length. The electrode body is formed by being wound in a state where the positive electrode and the negative electrode and the two separators are laminated,
The electric storage element according to claim 1, wherein the fold is formed over the entire separator along a winding direction of the electrode body. The electrode body is formed by being wound in a state where the positive electrode and the negative electrode and the two separators are laminated, and no active material is applied to the surfaces of the positive electrode and the negative electrode Has an uncoated area,
The electric storage element according to any one of claims 1 to 3, wherein the fold is formed at a position facing at least one of the positive electrode and the negative electrode in the uncoated region. The electricity storage element according to any one of claims 2 to 4, wherein the fold is formed at both ends of the electrode body in a winding axis direction. The electric storage element according to any one of claims 2 to 5, wherein the fold is formed along a winding direction of the electrode body. The power storage device according to claim 1, wherein the separator includes a first layer and a second layer made of a material different from that of the first layer. A positive electrode and a negative electrode;
A separator;
With
The separator is disposed between the positive electrode and the negative electrode;
The positive electrode, the negative electrode and the separator are laminated in a plurality of layers,
The separator has a fold in the vicinity of an end thereof. A positive electrode, a negative electrode, and a separator are provided, the separator is disposed between the positive electrode and the negative electrode, and an electrode body formed by stacking a plurality of layers of the positive electrode, the negative electrode, and the separator is manufactured. A winding device,
A crease forming part for forming a crease at an end of the separator;
A winding device comprising: the stacked positive electrode and negative electrode, and a winding unit that winds the separator. A positive electrode, a negative electrode, and a separator are provided, the separator is disposed between the positive electrode and the negative electrode, and an electrode body formed by stacking a plurality of layers of the positive electrode, the negative electrode, and the separator is manufactured. A winding method,
A crease forming step of forming a crease at an end of the separator;
A winding method comprising: winding the stacked positive electrode and negative electrode, and winding the separator.

Images