WO2012042881A1 - Battery electrode structure and nonaqueous electrolyte rechargeable battery - Google Patents

Battery electrode structure and nonaqueous electrolyte rechargeable battery Download PDF

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Publication number
WO2012042881A1
WO2012042881A1 PCT/JP2011/005488 JP2011005488W WO2012042881A1 WO 2012042881 A1 WO2012042881 A1 WO 2012042881A1 JP 2011005488 W JP2011005488 W JP 2011005488W WO 2012042881 A1 WO2012042881 A1 WO 2012042881A1
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Prior art keywords
electrode plate
battery
positive electrode
active material
positive
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PCT/JP2011/005488
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French (fr)
Japanese (ja)
Inventor
山本　哲也
康裕 貝崎
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三洋電機株式会社
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Publication of WO2012042881A1 publication Critical patent/WO2012042881A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/534—Electrode connections inside a battery casing characterised by the material of the leads or tabs
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrode structure used for a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.
  • Lithium ion secondary batteries have been put into practical use as power sources for mobile devices such as mobile phones and laptop computers, and are widely used. In recent years, with further miniaturization and higher functionality of these portable devices, the load on the lithium ion secondary battery has increased, and the demand for higher energy density of the lithium ion secondary battery has increased.
  • One method for achieving high energy density of the battery is to pack as many positive electrode active materials and negative electrode active materials as possible in a battery container of a predetermined size. Specifically, the positive electrode plate and the negative electrode plate are wound in a spiral shape, and a flat or cylindrical electrode body is housed in a rectangular or cylindrical container to increase the energy density. Can be achieved.
  • Conventional electrode bodies generally have a structure in which a current collecting tab connected to an external terminal protrudes in a direction perpendicular to one side of the electrode plate.
  • the generation of a magnetic field and the generation of heat may occur due to the concentration of the electric field and current at the corner where the current collecting tab and the electrode plate intersect.
  • the peripheral characteristics malfunction due to noise generated from the battery, and the battery characteristics are deteriorated, such as a reduction in battery life.
  • the present invention has been made in view of these problems, and an object thereof is to provide a technique capable of suppressing current concentration in a battery electrode structure.
  • An embodiment of the present invention is a battery electrode structure.
  • the battery electrode structure includes a battery electrode plate having an active material application region in which an active material is applied to a core body, a core body exposure region in which the core body is exposed, and a battery electrode plate in the core body exposure region.
  • a current collecting tab provided so as to protrude in a direction perpendicular to the reference side of the battery electrode plate along the current direction, and a line extending the side on the active material application region side of the current collecting tab, A first point at which a line extending from the reference side of the battery electrode plate intersects, a second point on the active material application region side of the current collecting tab at a predetermined distance from the first point, And a conductive member provided in a region connecting the third point on the reference side of the battery electrode plate at a predetermined distance from the first point.
  • the concentration of the electric field and / or current is reduced by providing the conductive member at the portion where the current collecting tab and the electrode plate intersect.
  • heat generation in the current collecting tab can be reduced, and consequently, deterioration of battery characteristics can be suppressed.
  • the side connecting the third point and the second point is a straight line, and the angle formed by the reference side of the battery electrode plate and the straight line is greater than 120 degrees and smaller than 160 degrees.
  • the side connecting the third point and the second point is a curve, and the angle formed by the reference side of the battery electrode plate and the tangent of the side at the third point is greater than 120 degrees and smaller than 160 degrees. Also good.
  • the conductive member may be a part of the battery electrode plate in the core exposed region.
  • the reference side of the battery electrode plate may be a recess with respect to the side of the active material application region along the current direction in the battery electrode plate.
  • the non-aqueous electrolyte secondary battery includes any one of the battery electrode structures described above.
  • FIG. 1A is a plan view showing the appearance of the lithium ion secondary battery according to Embodiment 1.
  • FIG. FIG. 1B is a schematic cross-sectional view along the line AA in FIG. 2A is a schematic perspective view of the electrode body according to Embodiment 1, and FIG. 2B is an enlarged schematic cross-sectional view of region B in FIG. 2A.
  • FIG. 3A is a schematic plan view of the positive electrode plate according to Embodiment 1 in the unfolded state
  • FIG. 3B is a plan view of the negative electrode plate according to Embodiment 1 in the unfolded state.
  • FIG. 5A is a diagram showing an analysis result of current distribution in an electrode structure that does not include a “conductive member”.
  • FIG. 5B is a diagram showing an analysis result of current distribution in the electrode structure of the first embodiment.
  • 6 is a graph showing the angle dependence of the maximum current density J in the electrode structure of the first embodiment.
  • FIG. 7A is a schematic plan view of the positive electrode plate according to Embodiment 2 in the unfolded state
  • FIG. 7B is a plan view of the negative electrode plate according to Embodiment 2 in the unfolded state. It is a plane schematic diagram.
  • FIG. 4 is an enlarged view of a main part showing an electrode structure of a positive electrode plate according to Embodiment 2.
  • 6 is a graph showing the angle dependence of the maximum current density J in the electrode structure of the second embodiment.
  • FIG. 1A is a plan view showing an appearance of the lithium ion secondary battery 1 according to Embodiment 1.
  • FIG. FIG. 1B is a schematic cross-sectional view along the line AA in FIG. 2A is a schematic perspective view of electrode body 100 according to Embodiment 1, and
  • FIG. 2B is an enlarged schematic cross-sectional view of region B in FIG.
  • FIG. 1A is a view in which a part of the battery outer body is cut away for easy understanding of the connection between the electrode body and the external terminal.
  • the lithium ion secondary battery 1 includes a battery outer package 2, a positive electrode current collecting tab 16, a negative electrode current collecting tab 26, a positive electrode plate 10, a negative electrode plate 20, and a separator as main components. 30.
  • the battery outer package 2 is an aluminum prismatic battery can having a thickness of about 4.5 mm, a width of 35 mm, and a height of about 42 mm, for example.
  • the electrode body 100 is accommodated in the battery exterior body 2 and impregnated with a nonaqueous electrolyte.
  • One end of the positive electrode current collecting tab 16 is connected to the electrode body 100, and the other end is connected to the lid portion 2 a of the battery exterior body 2. Therefore, the battery outer package 2 including the lid portion 2a also serves as a positive electrode terminal.
  • An opening 2b is formed in the lid 2a, and a negative electrode terminal 6 is inserted through the opening 2b through an insulating gasket 5.
  • the negative electrode current collecting tab 26 has one end connected to the electrode body 100 and the other end connected to the negative electrode terminal 6 via the connection electrode 7.
  • the positive electrode current collecting tab 16 is made of, for example, aluminum, and the negative electrode current collecting tab 26 is made of, for example, nickel.
  • An insulating spacer 8 is provided between the lid 2a and the electrode body 100 in order to prevent a short circuit therebetween.
  • the electrode body 100 has a shape in which the positive electrode plate 10 and the negative electrode plate 20 are wound in a spiral shape with the separator 30 interposed therebetween.
  • a separator 30 is further laminated on one main surface of the laminate composed of the positive electrode plate 10, the negative electrode plate 20, and the separator 30, here on the main surface of the negative electrode plate 20 opposite to the positive electrode plate 10.
  • a positive electrode current collecting tab 16 is connected to the positive electrode plate 10 by welding or the like, and a negative electrode current collecting tab 26 is connected to the negative electrode plate 20 by welding or the like (see FIGS. 3A and 3B). ).
  • the positive electrode plate 10 has a positive electrode core body 11 and positive electrode active material layers 13 provided on the main surfaces on both sides of the positive electrode core body 11, respectively.
  • the positive electrode core 11 is a strip-shaped member made of, for example, a conductive metal foil.
  • a conductive metal foil any conductive metal foil can be used without limitation as long as it does not dissolve in the nonaqueous electrolyte at the potential applied to the positive electrode plate 10 during charging and discharging, and an aluminum foil, for example, can be used. .
  • the positive electrode active material layer 13 includes positive electrode active material particles and a positive electrode binder.
  • the positive electrode active material particles include lithium such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 2 , LiCo 0.5 Ni 0.5 O 2 , LiNi 0.7 Co 0.2 Mn 0.1 O 2.
  • a contained transition metal oxide can be used.
  • any substance that electrochemically inserts and desorbs lithium can be used without limitation.
  • the positive electrode binder any known various binders that do not dissolve in a nonaqueous electrolyte solvent can be used without limitation.
  • fluorine resins such as polyvinylidene fluoride, polyimide resins, polyacrylonitrile, and the like are used. be able to.
  • the positive electrode active material layer 13 may contain a positive electrode conductive agent.
  • a positive electrode conductive agent various known conductive agents can be used.
  • a conductive carbon material particularly acetylene black or ketjen black can be used.
  • the length in the longitudinal direction, the length in the short direction, and the thickness of the positive electrode plate 10 are, for example, about 700 mm, about 55 mm, and about 100 ⁇ m, respectively.
  • the thicknesses of the positive electrode core body 11 and the positive electrode active material layer 13 are, for example, about 10 to 20 ⁇ m and about 100 to 150 ⁇ m, respectively.
  • the negative electrode plate 20 includes a negative electrode core 21 and negative electrode active material layers 23 provided on the main surfaces on both sides of the negative electrode core 21.
  • the negative electrode core 21 is a band-shaped member made of, for example, a conductive metal foil.
  • a metal foil such as copper, nickel, iron, titanium, cobalt, magnesium, zinc, aluminum, germanium, and indium, and an alloy foil made of a combination thereof can be used.
  • the negative electrode active material layer 23 includes negative electrode active material particles and a negative electrode binder.
  • the negative electrode active material particles are particles that can occlude and release lithium, and are made of, for example, a material alloyed with lithium.
  • materials that can be alloyed with lithium include silicon (silicon), germanium, tin, lead, zinc, magnesium, sodium, aluminum, gallium, indium, and alloys thereof. From the viewpoint of large charge / discharge capacity, silicon particles are particularly preferable.
  • the silicon particles are particles containing silicon as a main component, and examples of such particles include silicon simple particles, silicon alloy particles, and silicon oxide particles.
  • silicon alloy particles alloy particles containing 50 atomic% or more of silicon are preferably used.
  • the silicon alloy examples include Si—Co alloy, Si—Fe alloy, Si—Zn alloy, Si—Zr alloy, Si—Ti alloy, Si—Ni alloy, Si—W alloy, and Si—Cr alloy.
  • the material of the negative electrode active material layer 23 graphite is also applicable.
  • the surface of the negative electrode active material particles may be coated with a metal or the like. Examples of the coating method include an electroless plating method, an electrolytic plating method, a chemical reduction method, a vapor deposition method, a sputtering method, and a chemical vapor deposition method.
  • any of various known binders that do not dissolve in a nonaqueous electrolyte solvent can be used without limitation, but a binder having excellent mechanical strength and elasticity can be preferably used. Since the negative electrode binder has excellent mechanical strength and elasticity, it can be avoided that the negative electrode binder breaks due to the volume change of the negative electrode active material particles during occlusion and release of lithium, and follows the volume change of the negative electrode active material particles. The negative electrode active material layer 14b can be deformed. Thereby, the excellent charge / discharge cycle characteristics of the lithium ion secondary battery 1 can be obtained.
  • the binder having high mechanical strength include polyimide resin.
  • the length in the longitudinal direction, the length in the short direction, and the thickness of the negative electrode plate 20 are, for example, about 750 mm, about 57 mm, and about 75 ⁇ m, respectively.
  • the thicknesses of the negative electrode core 21 and the negative electrode active material layer 23 are, for example, about 10 to 20 ⁇ m and about 100 to 150 ⁇ m, respectively.
  • the separator 30 is, for example, a polyethylene microporous film.
  • the thickness of the separator 30 is, for example, about 20 ⁇ m.
  • nonaqueous electrolyte solvent impregnated in the battery outer package 2 examples include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate, and chain chains such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate.
  • Esters such as carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, ⁇ -butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, Ethers such as 2-methyltetrahydrofuran, nitriles such as acetonitrile, amides such as dimethylformamide and the like can be used alone or in combination.
  • solute of the nonaqueous electrolyte for example, LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2), LiC (CF 3 SO 2) 3, LiC ( such as C 2 F 5 SO 2) 3 , LiAsF 6, LiClO 4, Li 2 B 10 Cl 10, Li 2 B 12 Cl 12, and their Can be used.
  • LiXF y (wherein X is P, As, Sb, B, Bi, Al, Ga, or In, y is 6 when X is P, As, or Sb, and X is B, Bi, al, Ga or y is and those represented by a 4) when an in, lithium perfluoroalkyl sulfonic acid imide LiN (C m F 2m + 1 SO 2) (C n F 2n + 1 SO 2) (wherein, m and n are each independently an integer of 1 to 4), lithium perfluoroalkyl sulfonic acid methide LiC (C p F 2p + 1 SO 2) (C q F 2q + 1 SO 2) (C r F 2r + 1 SO 2) ( wherein, Solutes such as p, q and r are each independently an integer of 1 to 4 are preferably used.
  • LiPF 6 is particularly preferably used.
  • nonaqueous electrolyte a gel polymer electrolyte obtained by impregnating a polymer electrolyte such as polyethylene oxide or polyacrylonitrile with an electrolytic solution, or an inorganic solid electrolyte such as LiI or Li 3 N can be used.
  • the lithium ion secondary battery 1 is manufactured as follows, for example. First, positive electrode active material particles, a positive electrode binder, and a positive electrode conductive agent are charged into a solvent at a predetermined mass ratio and kneaded to prepare a positive electrode active material slurry. The positive electrode active material slurry is applied to both surfaces of the positive electrode core body 11 and then dried to form the positive electrode active material layers 13 on both surfaces of the positive electrode core body 11. At this time, the positive electrode core material 11 is exposed without forming the positive electrode active material layer 13 in one end region of the positive electrode core 11. Then, the obtained positive electrode core body 11 and the laminated body of the positive electrode active material layer 13 are compressed with a compression roller, and the positive electrode plate 10 is produced.
  • the negative electrode active material particles and the negative electrode binder are dispersed in water, and a thickener is added as necessary to prepare a negative electrode active material slurry.
  • the negative electrode active material slurry is applied to both surfaces of the negative electrode core body 21 and then dried to form the negative electrode active material layers 23 on both surfaces of the negative electrode core body 21.
  • the negative electrode active material layer 23 is not formed in the other end region of the negative electrode core 21, and the negative electrode core 21 is exposed. Thereafter, the obtained laminate of the negative electrode core 21 and the negative electrode active material layer 23 is compressed by a compression roller to produce the negative electrode plate 20.
  • the positive electrode plate 10 and the negative electrode plate 20 are connected to one end of each of the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 by welding. Then, the positive electrode plate 10 and the negative electrode plate 20 are superposed in a state of being insulated from each other with the separator 30 interposed therebetween, so that a laminate of the positive electrode plate 10, the negative electrode plate 20, and the separator 30 is formed. At this time, the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 are disposed on the same side when viewed in the short direction of the electrode plate and on the opposite sides when viewed in the longitudinal direction of the electrode plate (FIG. 3 ( A) and FIG. 3B). Moreover, the separator 30 is laminated
  • This laminated body is bent at a predetermined folding position and wound into a spiral shape.
  • the laminated body is wound, for example, such that the positive electrode current collecting tab 16 is located on the winding end side of the laminated body and the negative electrode current collecting tab 26 is located on the winding start side of the laminated body.
  • the outermost peripheral portion of the laminate is stopped with an insulating tape (not shown) so that the wound state is maintained. In this way, the flat electrode body 100 wound in a spiral shape is produced. Thereafter, the wound electrode body 100 and the non-aqueous electrolyte are inserted into the battery exterior body 2 to produce the lithium ion secondary battery 1.
  • the length in the winding direction, the length in the direction perpendicular to the winding direction, and the thickness of the spirally wound electrode body 100 are, for example, about 30 mm, about 50 mm, and about 5 mm, respectively.
  • the direction perpendicular to the winding direction coincides with the short direction of each electrode plate.
  • FIG. 3A is a schematic plan view of positive electrode plate 10 according to Embodiment 1 in the unfolded state
  • FIG. 3B is a negative electrode plate according to Embodiment 1 in the unfolded state
  • 20 is a schematic plan view of 20.
  • FIG. FIG. 4 is an enlarged view of a main part showing the electrode structure of the positive electrode plate 10.
  • 3A, 3B, and 4 are schematic views, and the scales of the illustrated electrode plate and current collecting tab are different from actual ones.
  • the vertical and horizontal directions of the positive electrode plate 10 illustrated in FIG. 3A and the negative electrode plate 20 illustrated in FIG. 3B coincide with the vertical and horizontal directions of the laminated body. Yes. That is, the positive electrode plate 10 and the negative electrode plate 20 are overlapped with each other with their respective vertical and horizontal directions shown in the drawings, and face each other.
  • a positive electrode active material layer 13 is applied to the positive electrode core body 11 so that an end region near one short side of the positive electrode core body 11 is exposed to form an active material application region.
  • the positive electrode current collecting tab 16 protrudes in a direction orthogonal to the reference side L1 of the positive electrode plate 10 along the current direction in the positive electrode plate 10 at a portion where the positive electrode core 11 is exposed (core exposed region). It is provided as follows.
  • the first vertex A is the point where the line extending the side of the positive electrode current collecting tab 16 on the positive electrode active material layer 13 side and the line extending the reference side L1 of the positive electrode plate 10 intersect.
  • the positive electrode core 11 in the region 15 connecting the third point C on the reference side L1 of the positive electrode plate 10 at a predetermined distance from A is the “conductive member” of the present invention.
  • the angle ⁇ formed by the reference side L1 and the side S connecting the second point B and the third point C is preferably larger than 120 degrees and smaller than 160 degrees.
  • the side S connecting the second point B and the third point C is a straight line, and the shape of the region 15 is a right triangle.
  • the side S connecting the second point B and the third point C may be a curve that has a base in the vicinity of the third point C.
  • the angle ⁇ is equal to the reference side L1 and the second point. It is defined by the angle formed by the tangent line at the third point C of the side S connecting B and the third point C.
  • the reference side L1 is recessed with respect to the side L3 of the positive electrode active material layer 13 along the current direction.
  • the reference side L1 that is a recess with respect to the side L3 can be formed by cutting out a part of the exposed portion of the positive electrode core 11.
  • the negative electrode active material layer 23 is applied to the negative electrode core 21 so that the end region near the other short side of the negative electrode core 21 is exposed, thereby forming an active material application region.
  • the negative electrode current collecting tab 26 protrudes in a direction orthogonal to the reference side L2 of the negative electrode plate 20 along the current direction in the negative electrode plate 20 at a portion where the negative electrode core 21 is exposed (core exposed region). It is provided as follows. Further, the negative electrode plate 20 is provided with a region 25 as in the positive electrode plate 10. Since the reference side L2 and the region 25 are symmetrical with the reference side L1 and the region 15, respectively, detailed description thereof is omitted.
  • the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 are arranged such that when the positive electrode plate 10 and the negative electrode plate 20 are wound, the positive electrode current collector tab 16 is disposed outside the spiral.
  • the current collecting tabs 26 are positioned with respect to each other such that they are disposed on the center side of the spiral. Note that the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 may be arranged such that the positive electrode current collecting tab 16 is disposed on the center side of the spiral and the negative electrode current collecting tab 26 is disposed outside the spiral.
  • FIG. 5A shows an analysis result of current distribution in an electrode structure that does not include a “conductive member”.
  • FIG. 5B shows an analysis result of current distribution in the electrode structure of the first embodiment.
  • FIG. 6 is a graph showing the angular dependence of the maximum current density J in the electrode structure of the first embodiment.
  • the angle dependence of the maximum current density J was calculated
  • the maximum current density J decreases when the angle ⁇ is greater than 90 degrees in both cases where H is 15 mm and 20 mm.
  • the maximum current density J is significantly reduced when the angle ⁇ is larger than 120 degrees and smaller than 160 degrees.
  • the electric field and / or current is concentrated in one place by providing the conductive member at the intersection of the current collecting tab and the electrode plate. Is alleviated. As a result, magnetic field generation and heat generation in the current collecting tab can be reduced, and consequently deterioration of characteristics of the lithium ion secondary battery 1 can be suppressed.
  • Embodiment 2 The basic configuration of the lithium ion secondary battery 1 according to Embodiment 2 is the same as that of the lithium ion secondary battery 1 of Embodiment 1 except for the form of the electrode structure of the electrode body.
  • the lithium ion secondary battery 1 according to the second embodiment will be described focusing on the configuration different from the first embodiment.
  • FIG. 7A is a schematic plan view of the positive electrode plate 10 according to the second embodiment in an unfolded state
  • FIG. 7B is a negative electrode plate according to the second embodiment in an unfolded state
  • 20 is a schematic plan view of 20
  • FIG. FIG. 8 is an enlarged view of a main part showing the electrode structure of the positive electrode plate 10.
  • the side of the positive electrode current collector tab 16 on the positive electrode active material layer 13 side is tapered, and the width of the positive electrode current collector tab 16 increases as it approaches the positive electrode plate 10.
  • the positive electrode current collecting tab 16 in the region 15 is the “conductive member” of the present invention.
  • the reference side L1 is flush with L3 of the positive electrode active material layer 13.
  • the negative electrode current collecting tab 26 in the region 25 is the “conductive member” of the present invention.
  • FIG. 9 is a graph showing the angle dependence of the maximum current density J in the electrode structure of the second embodiment.
  • the angle dependency of the maximum current density J is obtained when the length H of the tapered portion including the hypotenuse S is 5 mm, 15 mm, and 20 mm.
  • the maximum current density decreases when the angle ⁇ is larger than 90 degrees in any of H, 5 mm, 15 mm, and 20 mm.
  • the maximum current density J is significantly reduced when the angle ⁇ is larger than 120 degrees and smaller than 150 degrees.
  • the concentration of the electric field and / or current in one place is mitigated.
  • the present embodiment is advantageous for increasing the current because the effect of reducing current concentration is large.
  • SYMBOLS 1 Lithium ion secondary battery, 2 battery exterior body, 10 positive electrode plate, 11 positive electrode core, 13 positive electrode active material layer, 16 positive electrode current collection tab, 20 negative electrode plate, 21 negative electrode core, 23 negative electrode active material layer, 26 Negative current collector tab, 30 separator
  • the present invention is applicable to non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries.

Abstract

Provided is a battery electrode structure having a positive-electrode current collector tab (16) which is disposed, at a portion with a positive-electrode core (11) exposed (a core exposed area), so as to be protruded in a direction orthogonal to a reference side (L1) of a positive electrode plate (10) that extends along the direction of current on the positive electrode plate (10). A line extending from a side of the positive-electrode current collector tab (16) closer to a positive-electrode active material layer (13) and a line extending from the reference side (L1) of the positive-electrode current collector tab (16) intersect at a point, which is defined as a vertex (A) of a generally right-angled triangle. A line which connects between the side of the positive-electrode current collector tab (16) closer to the positive-electrode active material layer (13) and the reference side (L1) is defined as the hypotenuse (S) of the right-angled triangle. The positive-electrode core (11) having an area (15) of the right-angled triangle with the vertex (A) and the hypotenuse (S) is an "electrically conductive member" of the present invention.

Description

電池用電極構造および非水電解質二次電池Battery electrode structure and non-aqueous electrolyte secondary battery
　本発明は、リチウムイオン二次電池等の非水電解質二次電池に使用される電極構造に関する。 The present invention relates to an electrode structure used for a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.
　リチウムイオン二次電池は、携帯電話やノート型パソコンなどの携帯機器の電源として実用化され、広く普及している。近年、これらの携帯機器のさらなる小型化、高機能化にともなってリチウムイオン二次電池への負荷が大きくなっており、リチウムイオン二次電池の高エネルギー密度化への要求は高まっている。電池の高エネルギー密度化を達成する１つの方法としては、決められた大きさの電池容器内で、できる限り多くの正極活物質および負極活物質を詰め込むことが挙げられる。具体的には、正極電極板と負極電極板とを渦巻き状に巻回して扁平型や円筒型に成形した電極体を、角型や円筒型の容器内に収納することにより、高エネルギー密度化を達成することができる。 Lithium ion secondary batteries have been put into practical use as power sources for mobile devices such as mobile phones and laptop computers, and are widely used. In recent years, with further miniaturization and higher functionality of these portable devices, the load on the lithium ion secondary battery has increased, and the demand for higher energy density of the lithium ion secondary battery has increased. One method for achieving high energy density of the battery is to pack as many positive electrode active materials and negative electrode active materials as possible in a battery container of a predetermined size. Specifically, the positive electrode plate and the negative electrode plate are wound in a spiral shape, and a flat or cylindrical electrode body is housed in a rectangular or cylindrical container to increase the energy density. Can be achieved.
特開２００９－１４０９０４号公報JP 2009-140904 A
　従来の電極体では、外部端子と接続される集電タブが電極板の１辺に対して直交する方向に突出した構造が一般的である。従来の電極構造では、集電タブと電極板とが交差するコーナー部分に電界や電流が集中することで磁場の発生や発熱が生じることがある。この結果、電池から発生するノイズによる周辺部品の誤作動や、電池寿命の低下などの電池特性の劣化を招いていた。 Conventional electrode bodies generally have a structure in which a current collecting tab connected to an external terminal protrudes in a direction perpendicular to one side of the electrode plate. In the conventional electrode structure, the generation of a magnetic field and the generation of heat may occur due to the concentration of the electric field and current at the corner where the current collecting tab and the electrode plate intersect. As a result, the peripheral characteristics malfunction due to noise generated from the battery, and the battery characteristics are deteriorated, such as a reduction in battery life.
　本発明はこうした課題に鑑みてなされたものであり、その目的は、電池用電極構造において電流集中を抑制することができる技術の提供にある。 The present invention has been made in view of these problems, and an object thereof is to provide a technique capable of suppressing current concentration in a battery electrode structure.
　本発明のある態様は、電池用電極構造である。当該電池用電極構造は、芯体に活物質が塗布された活物質塗布領域と、芯体が露出した芯体露出領域とを有する電池用電極板と、芯体露出領域において、電池用電極板における電流方向に沿った電池用電極板の基準辺に対して直交する方向に突出するように設けられている集電タブと、集電タブの活物質塗布領域側の辺を伸ばした線と、電池用電極板の基準辺を伸ばした線とが交差する第１の点と、第１の点から所定の距離にある集電タブの活物質塗布領域側の辺上の第２の点と、第１の点から所定の距離にある電池用電極板の基準辺上の第３の点とを結ぶ領域に設けられた導電部材と、を備えることを特徴とする。 An embodiment of the present invention is a battery electrode structure. The battery electrode structure includes a battery electrode plate having an active material application region in which an active material is applied to a core body, a core body exposure region in which the core body is exposed, and a battery electrode plate in the core body exposure region. A current collecting tab provided so as to protrude in a direction perpendicular to the reference side of the battery electrode plate along the current direction, and a line extending the side on the active material application region side of the current collecting tab, A first point at which a line extending from the reference side of the battery electrode plate intersects, a second point on the active material application region side of the current collecting tab at a predetermined distance from the first point, And a conductive member provided in a region connecting the third point on the reference side of the battery electrode plate at a predetermined distance from the first point.
　上記態様の電池用電極構造によれば、集電タブと電極板とが交差する部分に導電部材を設けることにより、電界および／または電流が一カ所に集中することが緩和される。この結果、集電タブにおける発熱を低減させることができ、ひいては電池の特性劣化を抑制することができる。 According to the battery electrode structure of the above aspect, the concentration of the electric field and / or current is reduced by providing the conductive member at the portion where the current collecting tab and the electrode plate intersect. As a result, heat generation in the current collecting tab can be reduced, and consequently, deterioration of battery characteristics can be suppressed.
　上記態様の電池用電極構造において、第３の点と第２の点を結ぶ辺が直線であり、電池用電極板の基準辺と直線とがなす角が１２０度より大きく１６０度より小さくてもよい。また、第３の点と第２の点とを結ぶ辺が曲線であり、電池用電極板の基準辺と第３の点における辺の接線とがなす角が１２０度より大きく１６０度より小さくてもよい。導電部材が芯体露出領域の電池用電極板の一部であってもよい。電池用電極板の基準辺が、電池用電極板における電流方向に沿った活物質塗布領域の辺に対して凹部となっていてもよい。 In the battery electrode structure according to the above aspect, the side connecting the third point and the second point is a straight line, and the angle formed by the reference side of the battery electrode plate and the straight line is greater than 120 degrees and smaller than 160 degrees. Good. The side connecting the third point and the second point is a curve, and the angle formed by the reference side of the battery electrode plate and the tangent of the side at the third point is greater than 120 degrees and smaller than 160 degrees. Also good. The conductive member may be a part of the battery electrode plate in the core exposed region. The reference side of the battery electrode plate may be a recess with respect to the side of the active material application region along the current direction in the battery electrode plate.
　本発明の他の態様は、非水電解質二次電池である。当該非水電解質二次電池は、上述したいずれかの態様の電池用電極構造を備えることを特徴とする。 Another aspect of the present invention is a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery includes any one of the battery electrode structures described above.
　なお、上述した各要素を適宜組み合わせたものも、本件特許出願によって特許による保護を求める発明の範囲に含まれうる。 Note that a combination of the above-described elements as appropriate can be included in the scope of the invention for which protection by patent is sought by this patent application.
　本発明によれば、電池用電極構造において電流集中を抑制することができる。 According to the present invention, current concentration can be suppressed in the battery electrode structure.
図１（Ａ）は、実施の形態１に係るリチウムイオン二次電池の外観を示す平面図である。図１（Ｂ）は、図１（Ａ）のＡ－Ａ線に沿った概略断面図である。FIG. 1A is a plan view showing the appearance of the lithium ion secondary battery according to Embodiment 1. FIG. FIG. 1B is a schematic cross-sectional view along the line AA in FIG. 図２（Ａ）は、実施の形態１に係る電極体の概略斜視図であり、図２（Ｂ）は、図２（Ａ）における領域Ｂの拡大概略断面図である。2A is a schematic perspective view of the electrode body according to Embodiment 1, and FIG. 2B is an enlarged schematic cross-sectional view of region B in FIG. 2A. 図３（Ａ）は、展開された状態の実施の形態１に係る正極電極板の平面模式図であり、図３（Ｂ）は、展開された状態の実施の形態１に係る負極電極板の平面模式図である。FIG. 3A is a schematic plan view of the positive electrode plate according to Embodiment 1 in the unfolded state, and FIG. 3B is a plan view of the negative electrode plate according to Embodiment 1 in the unfolded state. It is a plane schematic diagram. 実施の形態１に係る正極電極板の電極構造を示す要部拡大図である。3 is an enlarged view of a main part showing an electrode structure of a positive electrode plate according to Embodiment 1. FIG. 図５（Ａ）は、「導電部材」を備えない電極構造における電流分布の解析結果を示す図である。図５（Ｂ）は、実施の形態１の電極構造における電流分布の解析結果を示す図である。FIG. 5A is a diagram showing an analysis result of current distribution in an electrode structure that does not include a “conductive member”. FIG. 5B is a diagram showing an analysis result of current distribution in the electrode structure of the first embodiment. 実施の形態１の電極構造における最大電流密度Ｊの角度依存性を示すグラフである。6 is a graph showing the angle dependence of the maximum current density J in the electrode structure of the first embodiment. 図７（Ａ）は、展開された状態の実施の形態２に係る正極電極板の平面模式図であり、図７（Ｂ）は、展開された状態の実施の形態２に係る負極電極板の平面模式図である。FIG. 7A is a schematic plan view of the positive electrode plate according to Embodiment 2 in the unfolded state, and FIG. 7B is a plan view of the negative electrode plate according to Embodiment 2 in the unfolded state. It is a plane schematic diagram. 実施の形態２に係る正極電極板の電極構造を示す要部拡大図である。FIG. 4 is an enlarged view of a main part showing an electrode structure of a positive electrode plate according to Embodiment 2. 実施の形態２の電極構造における最大電流密度Ｊの角度依存性を示すグラフである。6 is a graph showing the angle dependence of the maximum current density J in the electrode structure of the second embodiment.
　以下、本発明の実施の形態を図面を参照して説明する。なお、すべての図面において、同様な構成要素には同様の符号を付し、適宜説明を省略する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.
（実施の形態１）
　図１（Ａ）は、実施の形態１に係るリチウムイオン二次電池１の外観を示す平面図である。図１（Ｂ）は、図１（Ａ）のＡ－Ａ線に沿った概略断面図である。図２（Ａ）は、実施の形態１に係る電極体１００の概略斜視図であり、図２（Ｂ）は、図２（Ａ）における領域Ｂの拡大概略断面図である。図１（Ａ）は、電極体と外部端子との接続をわかりやすくするため電池外装体の一部を切り欠いた図となっている。 (Embodiment 1)
FIG. 1A is a plan view showing an appearance of the lithium ion secondary battery 1 according to Embodiment 1. FIG. FIG. 1B is a schematic cross-sectional view along the line AA in FIG. 2A is a schematic perspective view of electrode body 100 according to Embodiment 1, and FIG. 2B is an enlarged schematic cross-sectional view of region B in FIG. FIG. 1A is a view in which a part of the battery outer body is cut away for easy understanding of the connection between the electrode body and the external terminal.
　本実施の形態に係るリチウムイオン二次電池１は、主な構成として電池外装体２と、正極集電タブ１６と、負極集電タブ２６と、正極電極板１０、負極電極板２０、およびセパレータ３０を備える。 The lithium ion secondary battery 1 according to the present embodiment includes a battery outer package 2, a positive electrode current collecting tab 16, a negative electrode current collecting tab 26, a positive electrode plate 10, a negative electrode plate 20, and a separator as main components. 30.
　電池外装体２は、たとえば厚さが約４．５ｍｍ、幅が３５ｍｍ、高さが約４２ｍｍであるアルミニウム製の角形電池缶である。電池外装体２の内部には、電極体１００が収容され、非水電解質が含浸されている。正極集電タブ１６は、一端が電極体１００に接続され、他端が電池外装体２の蓋部２ａに接続されている。したがって、蓋部２ａを含む電池外装体２は正極端子を兼ねている。蓋部２ａには開口部２ｂが形成されており、開口部２ｂには絶縁ガスケット５を介して負極端子６が挿通されている。負極集電タブ２６は、一端が電極体１００に接続され、他端が接続電極７を介して負極端子６に接続されている。正極集電タブ１６は、たとえばアルミニウム製であり、負極集電タブ２６は、たとえばニッケル製である。蓋部２ａと電極体１００との間には、両者間のショートを防ぐために、絶縁スペーサ８が設けられている。 The battery outer package 2 is an aluminum prismatic battery can having a thickness of about 4.5 mm, a width of 35 mm, and a height of about 42 mm, for example. The electrode body 100 is accommodated in the battery exterior body 2 and impregnated with a nonaqueous electrolyte. One end of the positive electrode current collecting tab 16 is connected to the electrode body 100, and the other end is connected to the lid portion 2 a of the battery exterior body 2. Therefore, the battery outer package 2 including the lid portion 2a also serves as a positive electrode terminal. An opening 2b is formed in the lid 2a, and a negative electrode terminal 6 is inserted through the opening 2b through an insulating gasket 5. The negative electrode current collecting tab 26 has one end connected to the electrode body 100 and the other end connected to the negative electrode terminal 6 via the connection electrode 7. The positive electrode current collecting tab 16 is made of, for example, aluminum, and the negative electrode current collecting tab 26 is made of, for example, nickel. An insulating spacer 8 is provided between the lid 2a and the electrode body 100 in order to prevent a short circuit therebetween.
　電極体１００は、正極電極板１０と、負極電極板２０とがセパレータ３０を挟んで渦巻状に巻回された形状を有する。正極電極板１０、負極電極板２０、およびセパレータ３０で構成される積層体の一方の主表面、ここでは正極電極板１０と反対側の負極電極板２０の主表面には、さらにセパレータ３０が積層されている。これにより、積層体が渦巻き状に巻回されたときに、内側に位置する積層体の一方の電極板と外側に位置する積層体の他方の電極板との接触を防ぐことができる。正極電極板１０には正極集電タブ１６が溶接等により接続され、負極電極板２０には負極集電タブ２６が溶接等により接続されている（図３（Ａ）および図３（Ｂ）参照）。 The electrode body 100 has a shape in which the positive electrode plate 10 and the negative electrode plate 20 are wound in a spiral shape with the separator 30 interposed therebetween. A separator 30 is further laminated on one main surface of the laminate composed of the positive electrode plate 10, the negative electrode plate 20, and the separator 30, here on the main surface of the negative electrode plate 20 opposite to the positive electrode plate 10. Has been. Thereby, when the laminated body is wound in a spiral shape, contact between one electrode plate of the laminated body located on the inner side and the other electrode plate of the laminated body located on the outer side can be prevented. A positive electrode current collecting tab 16 is connected to the positive electrode plate 10 by welding or the like, and a negative electrode current collecting tab 26 is connected to the negative electrode plate 20 by welding or the like (see FIGS. 3A and 3B). ).
　正極電極板１０は、正極芯体１１と、正極芯体１１の両側の主表面にそれぞれ設けられた正極活物質層１３とを有する。正極芯体１１は、たとえば導電性金属箔で構成された帯状の部材である。この導電性金属箔としては、充放電時に正極電極板１０に加わる電位において、非水電解質に溶解せず安定に存在するものであれば制限なく用いることができ、たとえばアルミニウム箔を用いることができる。 The positive electrode plate 10 has a positive electrode core body 11 and positive electrode active material layers 13 provided on the main surfaces on both sides of the positive electrode core body 11, respectively. The positive electrode core 11 is a strip-shaped member made of, for example, a conductive metal foil. As the conductive metal foil, any conductive metal foil can be used without limitation as long as it does not dissolve in the nonaqueous electrolyte at the potential applied to the positive electrode plate 10 during charging and discharging, and an aluminum foil, for example, can be used. .
　正極活物質層１３は、正極活物質粒子と正極バインダーとを含む。正極活物質粒子としては、たとえばＬｉＣｏＯ２、ＬｉＮｉＯ２、ＬｉＭｎ２Ｏ４、ＬｉＭｎＯ２、ＬｉＣｏ０．５Ｎｉ０．５Ｏ２、ＬｉＮｉ０．７Ｃｏ０．２Ｍｎ０．１Ｏ２などのリチウム含有遷移金属酸化物を用いることができる。また、この他にも、リチウムを電気化学的に挿入脱離する物質であれば制限なく用いることができる。正極バインダーとしては、公知の様々なバインダーにおいて非水電解質の溶媒に溶解しないものであれば制限なく用いることができ、たとえば、ポリフッ化ビニリデン等のフッ素系樹脂、ポリイミド系樹脂、ポリアクリロニトリルなどを用いることができる。 The positive electrode active material layer 13 includes positive electrode active material particles and a positive electrode binder. Examples of the positive electrode active material particles include lithium such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 2 , LiCo 0.5 Ni 0.5 O 2 , LiNi 0.7 Co 0.2 Mn 0.1 O 2. A contained transition metal oxide can be used. In addition, any substance that electrochemically inserts and desorbs lithium can be used without limitation. As the positive electrode binder, any known various binders that do not dissolve in a nonaqueous electrolyte solvent can be used without limitation. For example, fluorine resins such as polyvinylidene fluoride, polyimide resins, polyacrylonitrile, and the like are used. be able to.
　正極活物質層１３は、正極導電剤を含んでいてもよい。正極導電剤としては、公知の様々な導電剤を用いることができ、たとえば、導電性の炭素材料、特にはアセチレンブラックやケッチェンブラックを用いることができる。 The positive electrode active material layer 13 may contain a positive electrode conductive agent. As the positive electrode conductive agent, various known conductive agents can be used. For example, a conductive carbon material, particularly acetylene black or ketjen black can be used.
　正極電極板１０の長手方向長さ、短手方向長さ、および厚さは、それぞれたとえば約７００ｍｍ、約５５ｍｍ、約１００μｍである。正極芯体１１および正極活物質層１３の厚さは、それぞれたとえば約１０～２０μｍ、約１００～１５０μｍである。 The length in the longitudinal direction, the length in the short direction, and the thickness of the positive electrode plate 10 are, for example, about 700 mm, about 55 mm, and about 100 μm, respectively. The thicknesses of the positive electrode core body 11 and the positive electrode active material layer 13 are, for example, about 10 to 20 μm and about 100 to 150 μm, respectively.
　負極電極板２０は、負極芯体２１と、負極芯体２１の両側の主表面にそれぞれ設けられた負極活物質層２３とを有する。負極芯体２１は、たとえば導電性金属箔で構成された帯状の部材である。この導電性金属箔としては、たとえば銅、ニッケル、鉄、チタン、コバルト、マグネシウム、亜鉛、アルミニウム、ゲルマニウム、インジウム等の金属、およびこれらの組み合わせからなる合金の箔を用いることができる。 The negative electrode plate 20 includes a negative electrode core 21 and negative electrode active material layers 23 provided on the main surfaces on both sides of the negative electrode core 21. The negative electrode core 21 is a band-shaped member made of, for example, a conductive metal foil. As the conductive metal foil, for example, a metal foil such as copper, nickel, iron, titanium, cobalt, magnesium, zinc, aluminum, germanium, and indium, and an alloy foil made of a combination thereof can be used.
　負極活物質層２３は、負極活物質粒子と負極バインダーとを含む。負極活物質粒子は、リチウムを吸蔵、放出することができる粒子であり、たとえばリチウムと合金化する材料からなる。リチウムと合金化する材料としては、シリコン（ケイ素）、ゲルマニウム、スズ、鉛、亜鉛、マグネシウム、ナトリウム、アルミニウム、ガリウム、インジウムおよびこれらの合金などが挙げられる。充放電容量が大きいという観点からは、シリコン粒子が特に好ましい。ここで、シリコン粒子はシリコンを主成分として含む粒子であり、このような粒子としては、シリコン単体粒子、シリコン合金粒子、シリコン酸化物粒子などが挙げられる。シリコン合金粒子としては、シリコンを５０原子％以上含む合金粒子などが好ましく用いられる。シリコン合金としては、Ｓｉ－Ｃｏ合金、Ｓｉ－Ｆｅ合金、Ｓｉ－Ｚｎ合金、Ｓｉ－Ｚｒ合金、Ｓｉ－Ｔｉ合金、Ｓｉ－Ｎｉ合金、Ｓｉ－Ｗ合金、Ｓｉ－Ｃｒ合金などが挙げられる。また、負極活物質層２３の材料としては、グラファイトも適用可能である。負極活物質粒子は、その表面が金属等で被覆されていてもよい。被覆方法としては、無電解めっき法、電解めっき法、化学還元法、蒸着法、スパッタリング法、化学気相成長法などが挙げられる。 The negative electrode active material layer 23 includes negative electrode active material particles and a negative electrode binder. The negative electrode active material particles are particles that can occlude and release lithium, and are made of, for example, a material alloyed with lithium. Examples of materials that can be alloyed with lithium include silicon (silicon), germanium, tin, lead, zinc, magnesium, sodium, aluminum, gallium, indium, and alloys thereof. From the viewpoint of large charge / discharge capacity, silicon particles are particularly preferable. Here, the silicon particles are particles containing silicon as a main component, and examples of such particles include silicon simple particles, silicon alloy particles, and silicon oxide particles. As silicon alloy particles, alloy particles containing 50 atomic% or more of silicon are preferably used. Examples of the silicon alloy include Si—Co alloy, Si—Fe alloy, Si—Zn alloy, Si—Zr alloy, Si—Ti alloy, Si—Ni alloy, Si—W alloy, and Si—Cr alloy. In addition, as the material of the negative electrode active material layer 23, graphite is also applicable. The surface of the negative electrode active material particles may be coated with a metal or the like. Examples of the coating method include an electroless plating method, an electrolytic plating method, a chemical reduction method, a vapor deposition method, a sputtering method, and a chemical vapor deposition method.
　負極バインダーとしては、公知の様々なバインダーにおいて非水電解質の溶媒に溶解しないものであれば制限なく用いることができるが、優れた機械的強度と弾性を有するバインダーを好ましく用いることができる。負極バインダーが優れた機械的強度と弾性を有することで、リチウムの吸蔵、放出時における負極活物質粒子の体積変化によって負極バインダーが破損することを回避でき、負極活物質粒子の体積変化に追随した負極活物質層１４ｂの変形が可能となる。これにより、リチウムイオン二次電池１の優れた充放電サイクル特性を得ることができる。高い機械的強度を有するバインダーとしては、たとえばポリイミド樹脂を挙げることができる。 As the negative electrode binder, any of various known binders that do not dissolve in a nonaqueous electrolyte solvent can be used without limitation, but a binder having excellent mechanical strength and elasticity can be preferably used. Since the negative electrode binder has excellent mechanical strength and elasticity, it can be avoided that the negative electrode binder breaks due to the volume change of the negative electrode active material particles during occlusion and release of lithium, and follows the volume change of the negative electrode active material particles. The negative electrode active material layer 14b can be deformed. Thereby, the excellent charge / discharge cycle characteristics of the lithium ion secondary battery 1 can be obtained. Examples of the binder having high mechanical strength include polyimide resin.
　負極電極板２０の長手方向長さ、短手方向長さ、および厚さは、それぞれたとえば約７５０ｍｍ、約５７ｍｍ、約７５μｍである。負極芯体２１および負極活物質層２３の厚さは、それぞれたとえば約１０～２０μｍ、約１００～１５０μｍである。 The length in the longitudinal direction, the length in the short direction, and the thickness of the negative electrode plate 20 are, for example, about 750 mm, about 57 mm, and about 75 μm, respectively. The thicknesses of the negative electrode core 21 and the negative electrode active material layer 23 are, for example, about 10 to 20 μm and about 100 to 150 μm, respectively.
　セパレータ３０は、たとえばポリエチレン微多孔膜である。セパレータ３０の厚さは、たとえば約２０μｍである。 The separator 30 is, for example, a polyethylene microporous film. The thickness of the separator 30 is, for example, about 20 μm.
　電池外装体２の内部に含浸される非水電解質の溶媒としては、たとえば、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状カーボネートや、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネートなどの鎖状カーボネート、酢酸メチル、酢酸エチル、酢酸プロピル、プロピオン酸メチル、プロピオン酸エチル、γ－ブチロラクトンなどのエステル類、１，２－ジメトキシエタン、１，２－ジエトキシエタン、テトラヒドロフラン、１，２－ジオキサン、２－メチルテトラヒドロフランなどのエーテル類、アセトニトリル等のニトリル類、ジメチルホルムアミド等のアミド類などを、単独でまたは複数組み合わせて使用することができる。 Examples of the nonaqueous electrolyte solvent impregnated in the battery outer package 2 include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate, and chain chains such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate. Esters such as carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, Ethers such as 2-methyltetrahydrofuran, nitriles such as acetonitrile, amides such as dimethylformamide and the like can be used alone or in combination.
　非水電解質の溶質としては、たとえば、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）（Ｃ４Ｆ９ＳＯ２）、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＣ（Ｃ２Ｆ５ＳＯ２）３、ＬｉＡｓＦ６、ＬｉＣｌＯ４、Ｌｉ２Ｂ１０Ｃｌ１０、Ｌｉ２Ｂ１２Ｃｌ１２など、およびそれらの混合物を用いることができる。特に、ＬｉＸＦｙ（式中、ＸはＰ、Ａｓ、Ｓｂ、Ｂ、Ｂｉ、Ａｌ、Ｇａ、またはＩｎであり、ＸがＰ、ＡｓまたはＳｂのときｙは６であり、ＸがＢ、Ｂｉ、Ａｌ、Ｇａ、またはＩｎのときｙは４である）で表されるものや、リチウムペルフルオロアルキルスルホン酸イミドＬｉＮ（ＣｍＦ２ｍ＋１ＳＯ２）（ＣｎＦ２ｎ＋１ＳＯ２）（式中、ｍおよびｎはそれぞれ独立して１～４の整数である）、リチウムペルフルオロアルキルスルホン酸メチドＬｉＣ（ＣｐＦ２ｐ＋１ＳＯ２）（ＣｑＦ２ｑ＋１ＳＯ２）（ＣｒＦ２ｒ＋１ＳＯ２）（式中、ｐ、ｑおよびｒはそれぞれ独立して１～４の整数である）などの溶質が好ましく用いられる。これらの中でも、ＬｉＰＦ６が特に好ましく用いられる。 As the solute of the nonaqueous electrolyte, for example, LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2), LiC (CF 3 SO 2) 3, LiC ( such as C 2 F 5 SO 2) 3 , LiAsF 6, LiClO 4, Li 2 B 10 Cl 10, Li 2 B 12 Cl 12, and their Can be used. In particular, LiXF y (wherein X is P, As, Sb, B, Bi, Al, Ga, or In, y is 6 when X is P, As, or Sb, and X is B, Bi, al, Ga or y is and those represented by a 4) when an in,, lithium perfluoroalkyl sulfonic acid imide LiN (C m F 2m + 1 SO 2) (C n F 2n + 1 SO 2) ( wherein, m and n are each independently an integer of 1 to 4), lithium perfluoroalkyl sulfonic acid methide LiC (C p F 2p + 1 SO 2) (C q F 2q + 1 SO 2) (C r F 2r + 1 SO 2) ( wherein, Solutes such as p, q and r are each independently an integer of 1 to 4 are preferably used. Among these, LiPF 6 is particularly preferably used.
　さらに非水電解質としては、ポリエチレンオキシド、ポリアクリロニトリルなどのポリマー電解質に電解液を含浸したゲル状ポリマー電解質や、ＬｉＩ、Ｌｉ３Ｎなどの無機固体電解質を用いることができる。 Further, as the nonaqueous electrolyte, a gel polymer electrolyte obtained by impregnating a polymer electrolyte such as polyethylene oxide or polyacrylonitrile with an electrolytic solution, or an inorganic solid electrolyte such as LiI or Li 3 N can be used.
　リチウムイオン二次電池１は、たとえば次のようにして作製される。まず、正極活物質粒子、正極バインダー、および正極導電剤が所定の質量比で溶媒に投入、混練されて正極活物質スラリーが調製される。この正極活物質スラリーが正極芯体１１の両面に塗布された後、乾燥されて、正極芯体１１の両面にそれぞれ正極活物質層１３が形成される。このとき、正極芯体１１の一方の端部領域に正極活物質層１３を形成せず、正極芯体１１を露出させる。その後、得られた正極芯体１１と正極活物質層１３の積層体が圧縮ローラで圧縮されて正極電極板１０が作製される。また、負極活物質粒子および負極バインダーが水に分散させ、さらに必要に応じて増粘剤が添加されて負極活物質スラリーが調製される。この負極活物質スラリーが負極芯体２１の両面に塗布された後、乾燥されて、負極芯体２１の両面にそれぞれ負極活物質層２３が形成される。このとき、負極芯体２１の他方の端部領域に負極活物質層２３を形成せず、負極芯体２１を露出させる。その後、得られた負極芯体２１と負極活物質層２３の積層体が圧縮ローラで圧縮されて負極電極板２０が作製される。 The lithium ion secondary battery 1 is manufactured as follows, for example. First, positive electrode active material particles, a positive electrode binder, and a positive electrode conductive agent are charged into a solvent at a predetermined mass ratio and kneaded to prepare a positive electrode active material slurry. The positive electrode active material slurry is applied to both surfaces of the positive electrode core body 11 and then dried to form the positive electrode active material layers 13 on both surfaces of the positive electrode core body 11. At this time, the positive electrode core material 11 is exposed without forming the positive electrode active material layer 13 in one end region of the positive electrode core 11. Then, the obtained positive electrode core body 11 and the laminated body of the positive electrode active material layer 13 are compressed with a compression roller, and the positive electrode plate 10 is produced. Moreover, the negative electrode active material particles and the negative electrode binder are dispersed in water, and a thickener is added as necessary to prepare a negative electrode active material slurry. The negative electrode active material slurry is applied to both surfaces of the negative electrode core body 21 and then dried to form the negative electrode active material layers 23 on both surfaces of the negative electrode core body 21. At this time, the negative electrode active material layer 23 is not formed in the other end region of the negative electrode core 21, and the negative electrode core 21 is exposed. Thereafter, the obtained laminate of the negative electrode core 21 and the negative electrode active material layer 23 is compressed by a compression roller to produce the negative electrode plate 20.
　正極電極板１０および負極電極板２０には、それぞれ正極集電タブ１６、負極集電タブ２６の一端が溶接により接続される。そして、正極電極板１０と負極電極板２０とが、セパレータ３０を挟んで互いに絶縁した状態で重ね合わせられ、正極電極板１０、負極電極板２０、およびセパレータ３０の積層体が形成される。このとき、正極集電タブ１６および負極集電タブ２６は、電極板の短手方向に見て同じ側であって、電極板の長手方向に見て互いに反対側に配置される（図３（Ａ）および図３（Ｂ）参照）。また、積層体の一方の主表面にセパレータ３０が積層される。 The positive electrode plate 10 and the negative electrode plate 20 are connected to one end of each of the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 by welding. Then, the positive electrode plate 10 and the negative electrode plate 20 are superposed in a state of being insulated from each other with the separator 30 interposed therebetween, so that a laminate of the positive electrode plate 10, the negative electrode plate 20, and the separator 30 is formed. At this time, the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 are disposed on the same side when viewed in the short direction of the electrode plate and on the opposite sides when viewed in the longitudinal direction of the electrode plate (FIG. 3 ( A) and FIG. 3B). Moreover, the separator 30 is laminated | stacked on one main surface of a laminated body.
　この積層体が所定の折り曲げ位置で折り曲げられて渦巻き状に巻回される。積層体は、たとえば正極集電タブ１６が積層体の巻き終わり側に位置し、負極集電タブ２６が積層体の巻き始め側に位置するようにして巻回される。積層体が渦巻状に巻回された後、巻回された状態が維持されるように積層体の最外周部が絶縁テープ（図示せず）によって止められる。このようにして、渦巻状に巻回された扁平状の電極体１００が作製される。その後、巻回された電極体１００と非水電解質とが電池外装体２に挿入されて、リチウムイオン二次電池１が作製される。渦巻き状に巻回された電極体１００の巻回し方向の長さ、巻回し方向と垂直な方向の長さ、および厚さは、それぞれ、たとえば約３０ｍｍ、約５０ｍｍ、約５ｍｍである。なお、巻回し方向と垂直な方向は、各電極板の短手方向と一致する。 This laminated body is bent at a predetermined folding position and wound into a spiral shape. The laminated body is wound, for example, such that the positive electrode current collecting tab 16 is located on the winding end side of the laminated body and the negative electrode current collecting tab 26 is located on the winding start side of the laminated body. After the laminate is wound in a spiral shape, the outermost peripheral portion of the laminate is stopped with an insulating tape (not shown) so that the wound state is maintained. In this way, the flat electrode body 100 wound in a spiral shape is produced. Thereafter, the wound electrode body 100 and the non-aqueous electrolyte are inserted into the battery exterior body 2 to produce the lithium ion secondary battery 1. The length in the winding direction, the length in the direction perpendicular to the winding direction, and the thickness of the spirally wound electrode body 100 are, for example, about 30 mm, about 50 mm, and about 5 mm, respectively. The direction perpendicular to the winding direction coincides with the short direction of each electrode plate.
　続いて、正極電極板１０および負極電極板２０の構造を詳細に説明する。図３（Ａ）は、展開された状態の実施の形態１に係る正極電極板１０の平面模式図であり、図３（Ｂ）は、展開された状態の実施の形態１に係る負極電極板２０の平面模式図である。図４は、正極電極板１０の電極構造を示す要部拡大図である。なお、図３（Ａ）、図３（Ｂ）および図４は模式図であり、図示された電極板および集電タブの縮尺は実際のものと異なる。図３（Ａ）に図示された正極電極板１０と図３（Ｂ）に図示された負極電極板２０の上下左右方向は、積層体となった状態でのそれぞれの上下左右方向と一致している。すなわち、正極電極板１０および負極電極板２０は、それぞれの上下左右方向が各図に示された状態のままで重ね合わされて互いに対向する。 Subsequently, the structure of the positive electrode plate 10 and the negative electrode plate 20 will be described in detail. FIG. 3A is a schematic plan view of positive electrode plate 10 according to Embodiment 1 in the unfolded state, and FIG. 3B is a negative electrode plate according to Embodiment 1 in the unfolded state. 20 is a schematic plan view of 20. FIG. FIG. 4 is an enlarged view of a main part showing the electrode structure of the positive electrode plate 10. 3A, 3B, and 4 are schematic views, and the scales of the illustrated electrode plate and current collecting tab are different from actual ones. The vertical and horizontal directions of the positive electrode plate 10 illustrated in FIG. 3A and the negative electrode plate 20 illustrated in FIG. 3B coincide with the vertical and horizontal directions of the laminated body. Yes. That is, the positive electrode plate 10 and the negative electrode plate 20 are overlapped with each other with their respective vertical and horizontal directions shown in the drawings, and face each other.
　図３（Ａ）に示すように、正極芯体１１の一方の短辺近傍の端部領域が露出するように正極芯体１１に正極活物質層１３が塗布されて活物質塗布領域が形成されている。正極集電タブ１６は、正極芯体１１が露出した部分（芯体露出領域）において、正極電極板１０における電流方向に沿った正極電極板１０の基準辺Ｌ１に対して直交する方向に突出するように設けられている。 As shown in FIG. 3A, a positive electrode active material layer 13 is applied to the positive electrode core body 11 so that an end region near one short side of the positive electrode core body 11 is exposed to form an active material application region. ing. The positive electrode current collecting tab 16 protrudes in a direction orthogonal to the reference side L1 of the positive electrode plate 10 along the current direction in the positive electrode plate 10 at a portion where the positive electrode core 11 is exposed (core exposed region). It is provided as follows.
　本実施の形態では、正極集電タブ１６の正極活物質層１３側の辺を伸ばした線と、正極電極板１０の基準辺Ｌ１とを伸ばした線とが交差する点を第１の頂点Ａとし、第１の頂点Ａから所定の距離（本実施の形態では長さＨ）にある正極集電タブ１６の正極活物質層１３側の辺上の第２の点Ｂと、第１の頂点Ａから所定の距離にある正極電極板１０の基準辺Ｌ１上にある第３の点Ｃとを結ぶ領域１５の正極芯体１１が本発明の「導電部材」となっている。基準辺Ｌ１と、第２の点Ｂと第３の点Ｃとを結ぶ辺Ｓとがなす角θは１２０度より大きく１６０度より小さいことが好ましい。本実施の形態では、第２の点Ｂと第３の点Ｃとを結ぶ辺Ｓは直線であり、領域１５の形状は直角三角形である。第２の点Ｂと第３の点Ｃとを結ぶ辺Ｓは第３の点Ｃの近傍で裾野を引くような曲線でもよく、その場合、角度θは、基準辺Ｌ１と、第２の点Ｂと第３の点Ｃとを結ぶ辺Ｓの第３の点Ｃにおける接線とがなす角で定義される。 In the present embodiment, the first vertex A is the point where the line extending the side of the positive electrode current collecting tab 16 on the positive electrode active material layer 13 side and the line extending the reference side L1 of the positive electrode plate 10 intersect. And a second point B on the side on the positive electrode active material layer 13 side of the positive electrode current collecting tab 16 at a predetermined distance (length H in the present embodiment) from the first vertex A, and the first vertex The positive electrode core 11 in the region 15 connecting the third point C on the reference side L1 of the positive electrode plate 10 at a predetermined distance from A is the “conductive member” of the present invention. The angle θ formed by the reference side L1 and the side S connecting the second point B and the third point C is preferably larger than 120 degrees and smaller than 160 degrees. In the present embodiment, the side S connecting the second point B and the third point C is a straight line, and the shape of the region 15 is a right triangle. The side S connecting the second point B and the third point C may be a curve that has a base in the vicinity of the third point C. In this case, the angle θ is equal to the reference side L1 and the second point. It is defined by the angle formed by the tangent line at the third point C of the side S connecting B and the third point C.
　基準辺Ｌ１は、電流方向に沿った正極活物質層１３の辺Ｌ３に対して凹部になっている。辺Ｌ３に対して凹部となる基準辺Ｌ１は、正極芯体１１の露出部分の一部を切り欠くことにより形成することができる。 The reference side L1 is recessed with respect to the side L3 of the positive electrode active material layer 13 along the current direction. The reference side L1 that is a recess with respect to the side L3 can be formed by cutting out a part of the exposed portion of the positive electrode core 11.
　図３（Ｂ）に示すように、負極芯体２１の他方の短辺近傍の端部領域が露出するように負極芯体２１に負極活物質層２３が塗布されて活物質塗布領域が形成されている。負極集電タブ２６は、負極芯体２１が露出した部分（芯体露出領域）において、負極電極板２０における電流方向に沿った負極電極板２０の基準辺Ｌ２に対して直交する方向に突出するように設けられている。また、負極電極板２０において、正極電極板１０と同様に領域２５が設けられている。基準辺Ｌ２および領域２５は、それぞれ基準辺Ｌ１および領域１５と対称関係にあるため、詳細な説明を省略する。 As shown in FIG. 3B, the negative electrode active material layer 23 is applied to the negative electrode core 21 so that the end region near the other short side of the negative electrode core 21 is exposed, thereby forming an active material application region. ing. The negative electrode current collecting tab 26 protrudes in a direction orthogonal to the reference side L2 of the negative electrode plate 20 along the current direction in the negative electrode plate 20 at a portion where the negative electrode core 21 is exposed (core exposed region). It is provided as follows. Further, the negative electrode plate 20 is provided with a region 25 as in the positive electrode plate 10. Since the reference side L2 and the region 25 are symmetrical with the reference side L1 and the region 15, respectively, detailed description thereof is omitted.
　本実施の形態では、正極集電タブ１６および負極集電タブ２６は、正極電極板１０および負極電極板２０が巻回された際に、正極集電タブ１６が渦巻きの外側に配置され、負極集電タブ２６が渦巻きの中心側に配置されるように、互いに位置決めされている。なお、正極集電タブ１６および負極集電タブ２６は、正極集電タブ１６が渦巻きの中心側に配置され、負極集電タブ２６が渦巻きの外側に配置されるようにしてもよい。 In the present embodiment, the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 are arranged such that when the positive electrode plate 10 and the negative electrode plate 20 are wound, the positive electrode current collector tab 16 is disposed outside the spiral. The current collecting tabs 26 are positioned with respect to each other such that they are disposed on the center side of the spiral. Note that the positive electrode current collecting tab 16 and the negative electrode current collecting tab 26 may be arranged such that the positive electrode current collecting tab 16 is disposed on the center side of the spiral and the negative electrode current collecting tab 26 is disposed outside the spiral.
（特性評価）
　比較のため、θ＝１８０度、すなわち、本発明の「導電部材」を備えない電極構造における電流分布を解析した。また、実施の形態１の電極構造において、θ＝１３５度、Ｈ＝１５ｍｍとしたときの電流分布を解析した。電流分布の解析には、有限要素法ソフトＡＮＳＹＳを用いた。図５（Ａ）に、「導電部材」を備えない電極構造における電流分布の解析結果を示す。また、図５（Ｂ）に、実施の形態１の電極構造における電流分布の解析結果を示す。 (Characteristic evaluation)
For comparison, θ = 180 degrees, that is, the current distribution in an electrode structure not including the “conductive member” of the present invention was analyzed. In the electrode structure of the first embodiment, the current distribution when θ = 135 degrees and H = 15 mm was analyzed. Finite element method software ANSYS was used to analyze the current distribution. FIG. 5A shows an analysis result of current distribution in an electrode structure that does not include a “conductive member”. FIG. 5B shows an analysis result of current distribution in the electrode structure of the first embodiment.
　図５（Ａ）に示すように、「導電部材」を備えない電極構造では、集電タブと電極体とが交差する部分に電流が集中し、電流値が高くなることがわかる。これに対して、図５（Ｂ）に示すように、実施の形態１の電極構造では、１箇所に電流が集中せず、局所的に電流値が高くなることが抑制されている様子がわかる。 As shown in FIG. 5 (A), in the electrode structure that does not include the “conductive member”, it can be seen that the current concentrates at the intersection of the current collecting tab and the electrode body, and the current value increases. On the other hand, as shown in FIG. 5B, it can be seen that in the electrode structure of the first embodiment, the current is not concentrated at one place and the current value is suppressed from being locally increased. .
　次に、正極電極板１０および正極集電タブ１６の領域内で最大となる電流値（最大電流値Ｊ）の角度θ依存性を検証した。図６は、実施の形態１の電極構造における最大電流密度Ｊの角度依存性を示すグラフである。なお、図４に示す切り込み部長さＨを１５ｍｍ、２０ｍｍにした場合についてそれぞれ最大電流密度Ｊの角度依存性を求めた。図６の縦軸は、角度θ＝１８０度のときの最大電流密度Ｊ（１８０）を基準としたときの最大電流密度Ｊの比率を示す。図６に示すように、Ｈが１５ｍｍ、２０ｍｍのいずれの場合にも、角度θが９０度より大きい場合に、最大電流密度が低下することがわかる。特に、角度θが１２０度より大きく１６０度より小さい場合に、最大電流密度Ｊが顕著に低下することが見いだされた。 Next, the angle θ dependency of the maximum current value (maximum current value J) in the region of the positive electrode plate 10 and the positive electrode current collecting tab 16 was verified. FIG. 6 is a graph showing the angular dependence of the maximum current density J in the electrode structure of the first embodiment. In addition, the angle dependence of the maximum current density J was calculated | required, respectively about the case where notch part length H shown in FIG. 4 is 15 mm and 20 mm. The vertical axis in FIG. 6 represents the ratio of the maximum current density J when the maximum current density J (180) when the angle θ = 180 degrees is used as a reference. As shown in FIG. 6, it can be seen that the maximum current density decreases when the angle θ is greater than 90 degrees in both cases where H is 15 mm and 20 mm. In particular, it has been found that the maximum current density J is significantly reduced when the angle θ is larger than 120 degrees and smaller than 160 degrees.
　以上説明した実施の形態１に係るリチウムイオン二次電池１によれば、集電タブと電極板とが交差する部分に導電部材を設けることにより、電界および／または電流が一カ所に集中することが緩和される。この結果、集電タブにおける磁場発生や発熱を低減させることができ、ひいてはリチウムイオン二次電池１の特性劣化を抑制することができる。 According to the lithium ion secondary battery 1 according to the first embodiment described above, the electric field and / or current is concentrated in one place by providing the conductive member at the intersection of the current collecting tab and the electrode plate. Is alleviated. As a result, magnetic field generation and heat generation in the current collecting tab can be reduced, and consequently deterioration of characteristics of the lithium ion secondary battery 1 can be suppressed.
（実施の形態２）
　実施の形態２に係るリチウムイオン二次電池１の基本的な構成は、電極体の電極構造の形態を除き、実施の形態１のリチウムイオン二次電池１と共通する。以下、実施の形態２に係るリチウムイオン二次電池１について実施の形態１と異なる構成を中心に説明する。 (Embodiment 2)
The basic configuration of the lithium ion secondary battery 1 according to Embodiment 2 is the same as that of the lithium ion secondary battery 1 of Embodiment 1 except for the form of the electrode structure of the electrode body. Hereinafter, the lithium ion secondary battery 1 according to the second embodiment will be described focusing on the configuration different from the first embodiment.
　図７（Ａ）は、展開された状態の実施の形態２に係る正極電極板１０の平面模式図であり、図７（Ｂ）は、展開された状態の実施の形態２に係る負極電極板２０の平面模式図である。図８は、正極電極板１０の電極構造を示す要部拡大図である。 FIG. 7A is a schematic plan view of the positive electrode plate 10 according to the second embodiment in an unfolded state, and FIG. 7B is a negative electrode plate according to the second embodiment in an unfolded state. 20 is a schematic plan view of 20. FIG. FIG. 8 is an enlarged view of a main part showing the electrode structure of the positive electrode plate 10.
　本実施の形態では、正極集電タブ１６の正極活物質層１３側の辺がテーパ状になっており、正極集電タブ１６の幅が正極電極板１０に近づくにつれて太くなっている。この構造により、本実施の形態では、領域１５の正極集電タブ１６が本発明の「導電部材」となっている。また、基準辺Ｌ１は、正極活物質層１３のＬ３と面一である。同様に、負極電極板２０の側では、領域２５の負極集電タブ２６が本発明の「導電部材」となっている。 In the present embodiment, the side of the positive electrode current collector tab 16 on the positive electrode active material layer 13 side is tapered, and the width of the positive electrode current collector tab 16 increases as it approaches the positive electrode plate 10. With this structure, in this embodiment, the positive electrode current collecting tab 16 in the region 15 is the “conductive member” of the present invention. The reference side L1 is flush with L3 of the positive electrode active material layer 13. Similarly, on the negative electrode plate 20 side, the negative electrode current collecting tab 26 in the region 25 is the “conductive member” of the present invention.
（特性評価）
　実施の形態２に係るリチウムイオン二次電池１の電極構造において、正極電極板１０および正極集電タブ１６の領域内での最大電流値Ｊの角度θ依存性を検証した。図９は、実施の形態２の電極構造における最大電流密度Ｊの角度依存性を示すグラフである。なお、本実施の形態では、図８に示すように、斜辺Ｓを含むテーパ部の長さＨを５ｍｍ、１５ｍｍ、２０ｍｍにした場合についてそれぞれ最大電流密度Ｊの角度依存性を求めた。図９の縦軸は、角度θ＝９０度のときの最大電流密度Ｊ（９０）を基準としたときの最大電流密度Ｊの比率を示す。図９に示すように、Ｈが５ｍｍ、１５ｍｍ、２０ｍｍのいずれの場合にも角度θが９０度より大きい場合に、最大電流密度が低下することがわかる。特に、角度θが１２０度より大きく１５０度より小さい場合に、最大電流密度Ｊが顕著に低下することが見いだされた。 (Characteristic evaluation)
In the electrode structure of the lithium ion secondary battery 1 according to Embodiment 2, the angle θ dependency of the maximum current value J in the region of the positive electrode plate 10 and the positive electrode current collecting tab 16 was verified. FIG. 9 is a graph showing the angle dependence of the maximum current density J in the electrode structure of the second embodiment. In the present embodiment, as shown in FIG. 8, the angle dependency of the maximum current density J is obtained when the length H of the tapered portion including the hypotenuse S is 5 mm, 15 mm, and 20 mm. The vertical axis in FIG. 9 shows the ratio of the maximum current density J when the maximum current density J (90) at the angle θ = 90 degrees is used as a reference. As shown in FIG. 9, it can be seen that the maximum current density decreases when the angle θ is larger than 90 degrees in any of H, 5 mm, 15 mm, and 20 mm. In particular, it has been found that the maximum current density J is significantly reduced when the angle θ is larger than 120 degrees and smaller than 150 degrees.
　以上説明した実施の形態２に係るリチウムイオン二次電池１によれば、実施の形態１と同様に、電界および／または電流が一カ所に集中することが緩和される。この他、本実施の形態は、電流集中の緩和効果が大きいために大電流化に有利である。 According to the lithium ion secondary battery 1 according to the second embodiment described above, as in the first embodiment, the concentration of the electric field and / or current in one place is mitigated. In addition, the present embodiment is advantageous for increasing the current because the effect of reducing current concentration is large.
　本発明は、上述の各実施の形態に限定されるものではなく、当業者の知識に基づいて各種の設計変更等の変形を加えることも可能であり、そのような変形が加えられた実施の形態も本発明の範囲に含まれうるものである。 The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. The form can also be included in the scope of the present invention.
１　リチウムイオン二次電池、２　電池外装体、１０　正極電極板、１１　正極芯体、１３　正極活物質層、１６　正極集電タブ、２０　負極電極板、２１　負極芯体、２３　負極活物質層、２６　負極集電タブ、３０　セパレータ DESCRIPTION OF SYMBOLS 1 Lithium ion secondary battery, 2 battery exterior body, 10 positive electrode plate, 11 positive electrode core, 13 positive electrode active material layer, 16 positive electrode current collection tab, 20 negative electrode plate, 21 negative electrode core, 23 negative electrode active material layer, 26 Negative current collector tab, 30 separator
　本発明は、リチウムイオン二次電池等の非水電解質二次電池に適用可能である。 The present invention is applicable to non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries.

Claims (6)

  1. 　芯体に活物質が塗布された活物質塗布領域と、前記芯体が露出した芯体露出領域とを有する電池用電極板と、
    　前記芯体露出領域において、前記電池用電極板における電流方向に沿った前記電池用電極板の基準辺に対して直交する方向に突出するように設けられている集電タブと、
    　前記集電タブの前記活物質塗布領域側の辺を伸ばした線と、前記電池用電極板の基準辺を伸ばした線とが交差する第１の点と、前記第１の点から所定の距離にある前記集電タブの前記活物質塗布領域側の辺上の第２の点と、前記第１の点から所定の距離にある前記電池用電極板の基準辺上の第３の点とを結ぶ領域に設けられた導電部材と、
    　を備えることを特徴とする電池用電極構造。     An electrode plate for a battery having an active material application region in which an active material is applied to the core, and a core exposed region in which the core is exposed;
    In the core exposed region, a current collecting tab provided so as to protrude in a direction orthogonal to a reference side of the battery electrode plate along a current direction in the battery electrode plate;
    A first point where a line extending the active material application region side of the current collecting tab intersects a line extending a reference side of the battery electrode plate, and a predetermined distance from the first point And a third point on the reference side of the battery electrode plate at a predetermined distance from the first point. A conductive member provided in a region to be connected;
    A battery electrode structure comprising:
  2. 　前記第３の点と前記第２の点を結ぶ辺が直線であり、前記電池用電極板の基準辺と前記直線とがなす角が１２０度より大きく１６０度より小さい請求項１に記載の電池用電極構造。 The battery according to claim 1, wherein a side connecting the third point and the second point is a straight line, and an angle formed by a reference side of the battery electrode plate and the straight line is greater than 120 degrees and smaller than 160 degrees. Electrode structure.
  3. 　前記第３の点と前記第２の点とを結ぶ辺が曲線であり、前記電池用電極板の基準辺と前記第３の点における前記辺の接線とがなす角が１２０度より大きく１６０度より小さい請求項１に記載の電池用電極構造。 The side connecting the third point and the second point is a curve, and the angle formed by the reference side of the battery electrode plate and the tangent of the side at the third point is greater than 120 degrees and 160 degrees. The battery electrode structure according to claim 1, which is smaller.
  4. 　前記導電部材が前記芯体露出領域の前記電池用電極板の一部である請求項１乃至３のいずれか１項に記載の電池用電極構造。 The battery electrode structure according to any one of claims 1 to 3, wherein the conductive member is a part of the battery electrode plate in the core exposed region.
  5. 　前記電池用電極板の基準辺が、前記電池用電極板における電流方向に沿った前記活物質塗布領域の辺に対して凹部となっている請求項１乃至４のいずれか１項に記載の電池用電極構造。 The battery according to any one of claims 1 to 4, wherein a reference side of the battery electrode plate is a recess with respect to a side of the active material application region along a current direction in the battery electrode plate. Electrode structure.
  6. 　請求項１乃至５のいずれか１項に記載の電池用電極構造を備えた非水電解質二次電池。 A nonaqueous electrolyte secondary battery comprising the battery electrode structure according to any one of claims 1 to 5.
PCT/JP2011/005488 2010-09-30 2011-09-29 Battery electrode structure and nonaqueous electrolyte rechargeable battery WO2012042881A1 (en)

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JPH1116577A (en) * 1997-06-26 1999-01-22 Shin Kobe Electric Mach Co Ltd Nonaqueous electrolyte battery
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