WO2017094526A1 - Électrode pour éléments électrochimiques, et pile rechargeable lithium-ion - Google Patents

Électrode pour éléments électrochimiques, et pile rechargeable lithium-ion Download PDF

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Publication number
WO2017094526A1
WO2017094526A1 PCT/JP2016/084217 JP2016084217W WO2017094526A1 WO 2017094526 A1 WO2017094526 A1 WO 2017094526A1 JP 2016084217 W JP2016084217 W JP 2016084217W WO 2017094526 A1 WO2017094526 A1 WO 2017094526A1
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Prior art keywords
electrode
current collector
negative electrode
main body
positive electrode
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PCT/JP2016/084217
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English (en)
Japanese (ja)
Inventor
阿部　敏浩
裕志 橋本
阿部　浩史
石澤　政嗣
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日立マクセル株式会社
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Publication of WO2017094526A1 publication Critical patent/WO2017094526A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/66—Current collectors
    • H01G11/70—Current collectors characterised by their structure
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • 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
    • H01M4/06—Electrodes for primary cells
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • 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
    • H01M4/72—Grids
    • H01M4/74—Meshes or woven material; Expanded metal
    • 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 for an electrochemical element excellent in reliability and a lithium ion secondary battery having the electrode.
  • lithium ion secondary batteries have high voltage and high capacity, there are great expectations for their development.
  • such a high capacity negative electrode material has a large irreversible capacity, and a relatively large amount of Li released from the positive electrode by the initial charge of the battery and occluded in the high capacity negative electrode material is negative during the next discharge.
  • the battery capacity could not be sufficiently increased due to the use of a high capacity negative electrode material.
  • the positive electrode current collector and the negative electrode current collector having through-holes are used for various purposes other than the pre-doping as described above, for example, for the purpose of maintaining good properties of the electrode mixture layer. (Patent Document 2, etc.).
  • an electrode mixture layer (a positive electrode mixture layer containing a positive electrode active material or a negative electrode mixture layer containing a negative electrode active material such as a high-capacity negative electrode material) is obtained using a current collector having a plurality of through holes.
  • an electrode in the form of a tab is formed by a portion of the current collector that is exposed without being formed, or when a lithium ion secondary battery is formed using such an electrode, the current is collected at a specific portion of the electrode. It has been clarified by the present inventors that defects such as body breakage tend to occur.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide an electrode for an electrochemical element excellent in reliability and a lithium ion secondary battery having the electrode.
  • the electrode for an electrochemical element of the present invention that has achieved the above object is used for a positive electrode or a negative electrode of an electrochemical element, and an electrode mixture layer containing an electrode active material is disposed on one side of a current collector or A main body portion having both sides of the current collector, and a tab portion having no electrode mixture layer on both surfaces of the current collector, the tab portion projecting from the main body portion, and the current collector has one side A plurality of through holes penetrating from one side to the other surface, and the plurality of through holes are regularly arranged, and one through hole and another through hole closest to the one through hole A straight line connecting the tab portion and the tab portion does not exist within a range of 0 ° ⁇ 20 ° from a direction perpendicular to the direction in which the tab portion protrudes from the main body portion.
  • an electrode for an electrochemical element of the present invention is used for a positive electrode or a negative electrode of an electrochemical element, and an electrode mixture layer containing an electrode active material is disposed on one side or both sides of a current collector.
  • a main body portion, and a tab portion having no electrode mixture layer on both sides of the current collector, the main body portion is rectangular in plan view, and the current collector is separated from one side to the other.
  • a plurality of through-holes penetrating the surface, and the plurality of through-holes are regularly arranged; one through-hole and another through-hole closest to the one through-hole
  • the connecting straight line does not exist within a range of 0 ° ⁇ 20 ° from a direction parallel to the short side of the main body.
  • the lithium ion secondary battery of the present invention has a laminated electrode body in which a positive electrode and a negative electrode are laminated via a separator, and a non-aqueous electrolyte, and at least the positive electrode has the electrochemical properties of the present invention. It is an element electrode.
  • an electrochemical element electrode having excellent reliability and a lithium ion secondary battery having the electrode.
  • Electrode for electrochemical device of the present invention is used as a positive electrode or a negative electrode of an electrochemical element such as a lithium ion secondary battery, a lithium primary battery, or a capacitor.
  • the electrode of the present invention has a main body having an electrode mixture layer (positive electrode mixture layer or negative electrode mixture layer) containing an electrode active material (positive electrode active material or negative electrode active material) on one side or both sides of a current collector. And a tab portion that is exposed without forming an electrode mixture layer on a part of the current collector, and is used to electrically connect the part to other members of the electrochemical element.
  • an electrode mixture layer positive electrode mixture layer or negative electrode mixture layer
  • an electrode active material positive electrode active material or negative electrode active material
  • FIG. 1 is a plan view schematically showing an example of the electrode (positive electrode) of the present invention.
  • An electrode (positive electrode) 10 shown in FIG. 1 has an electrode mixture layer (positive electrode mixture layer) 11 on the surface of a current collector 12.
  • a portion having the electrode mixture layer 11 is a main body portion.
  • the electrode 10 is provided with a tab portion 13 composed of an exposed portion where the electrode mixture layer is not formed on both surfaces of the current collector 12.
  • the main body of the electrode shown in FIG. 1 is rectangular in plan view (the shape of the main body described below means the shape in plan view unless otherwise specified).
  • the electrode of the present invention has a main body portion having an electrode mixture layer on the surface of the current collector and a tab portion.
  • the current collector according to the electrode of the present invention has a plurality of through holes penetrating from one side to the other side.
  • These through holes of the current collector have, for example, an effect of increasing the adhesion between the electrode mixture layer and the current collector, and also serve as a passage for the non-aqueous electrolyte solution of the electrochemical element. Since the non-aqueous electrolyte can penetrate more uniformly throughout the mixture layer, it contributes to improving the characteristics of the electrochemical device.
  • the through hole of the current collector according to the electrode of the present invention has Since the Li ion released from the Li supply source (non-aqueous electrolyte containing the released Li ion) becomes a path, it becomes possible to advance pre-doping more efficiently.
  • FIG. 1 in order to avoid that drawing becomes complicated, the through-hole is not shown in the exposed part of the electrical power collector 12 which comprises the tab part 13.
  • FIG. 1 in order to avoid that drawing becomes complicated, the through-hole is not shown in the exposed part of the electrical power collector 12 which comprises the tab part 13.
  • the tab is the main body.
  • cracks and breaks of the tab portion and the main body portion are likely to occur in a direction perpendicular to the direction projecting from the direction or a direction close thereto.
  • the main body When the main body is rectangular, the long side direction of the main body (vertical direction in FIG. 1) in the manufacturing process of the electrode and in the manufacturing process of the electrochemical element including the lithium ion secondary battery using the electrode. Often stress is applied.
  • the negative electrode expands greatly due to charging. In this case, stress generated by the expansion of the negative electrode is applied to the negative electrode, or stress due to expansion of the negative electrode. (Pressing force) is applied to the positive electrode.
  • the present inventors have an influence on the arrangement of a plurality of through holes provided in the current collector. I found out. That is, in a current collector having a plurality of through holes, anisotropy occurs in the ease of tearing depending on the arrangement of these through holes, and the direction in which tearing is easier is perpendicular to the direction in which the tab portion protrudes from the main body portion. When facing a direction that is near or perpendicular to the vertical direction, or when facing a direction that is parallel or nearly parallel to the short-side direction of the rectangular main body portion, Breaking easily occurs.
  • the arrangement of the plurality of through holes in the current collector used for the electrode is adjusted, and the direction in which the current collector is more easily torn is perpendicular to and perpendicular to the direction in which the tab portion protrudes from the main body portion. Avoiding cracks and breaks in the tab part and body part as described above, by avoiding the near direction or parallel to the direction of the short side of the rectangular body part and the direction close to parallel It is possible to provide an electrode with excellent properties.
  • a plurality of through holes are regularly arranged, and a straight line connecting one through hole and another through hole closest to the through hole.
  • it does not exist within the range of 0 ° ⁇ 20 ° from the direction perpendicular to the direction in which the tab portion projects from the main body, or within the range of 0 ° ⁇ 20 ° from the direction parallel to the short side direction of the rectangular main body.
  • the tab part regardless of where it protrudes from the main body part, cracks and breaks tend to occur in the direction perpendicular to the direction protruding from the main body part or in a direction close thereto, but for example, the shape of the main body part 1 is rectangular in a plan view as shown in FIG. 1, because the stress is applied mainly in the long side direction of the main body due to the normal manufacturing process of the electrode and the battery, the tab portion is from the short side of the main body.
  • cracks and breaks are particularly likely to occur in the main body portion in a direction parallel to the short side or in a direction close thereto.
  • the straight line connecting the through hole and the nearest other through-hole does not exist within the range of 0 ° ⁇ 20 ° from the direction perpendicular to the direction in which the tab portion protrudes from the main body, the straight line Since it does not exist within the range of 0 ° ⁇ 20 ° from the direction parallel to the short side direction of the part, it is possible to satisfactorily suppress the occurrence of cracks and breaks in the main body part together with the tab part.
  • FIG. 2 is a plan view schematically showing an example of the arrangement of the through holes in the current collector used for the electrode of the present invention.
  • the current collector 12 shown in FIG. 2 has a plurality of through holes (indicated by circles in the figure) that penetrate from one side to the other side.
  • each through hole is arranged in a specific pattern, specifically, in a staggered arrangement, and includes one through hole 120 and six surrounding holes. The distances from the through holes are all equal, and these six through holes correspond to the through hole closest to one through hole 120.
  • straight lines connecting the through holes 120 and the six through holes closest to the through holes 120 are indicated by alternate long and short dash lines, but the current collector 12 is easily split along the direction indicated by the alternate long and short dashed lines. . Therefore, in the electrode of the present invention, when a current collector in which a plurality of through holes are arranged in the pattern shown in FIG. 2 is used, the direction indicated by the alternate long and short dash line in the figure is such that the tab portion is separated from the main body portion. Orient the current collector so that it does not exist within the range of 0 ° ⁇ 20 ° from the direction perpendicular to the protruding direction or within the range of 0 ° ⁇ 20 ° from the direction parallel to the short side of the rectangular main body.
  • the electrode when the electrode is manufactured, the electrochemical element is manufactured, and further, when the lithium ion secondary battery is used, the direction in which the tab portion and the main body portion of the electrode are likely to be cracked or broken easily breaks the current collector. Since the direction does not match, the reliability of the electrode can be improved.
  • FIG. 3 and 4 are plan views schematically showing other examples of the arrangement of the through holes in the current collector used for the electrode of the present invention.
  • the current collector 12 shown in FIG. 3 is an example in which the through holes (indicated by circles in the figure) are arranged in a staggered arrangement. Since the distance between the upper and lower rows is wider, a straight line (one-dot chain line in the figure) connecting one through hole 120 and the other through hole closest to the through hole 120 exists only in the left-right direction in the figure.
  • the horizontal direction in the figure is 0 from the direction perpendicular to the direction in which the tab portion protrudes from the main body portion.
  • the direction of the current collector is adjusted so that it does not exist within the range of ⁇ 20 ° or within the range of 0 ° ⁇ 20 ° from the direction parallel to the short side of the rectangular main body.
  • each through hole (indicated by a circle in the figure) is arranged linearly in the vertical direction and the horizontal direction in the figure, that is, arranged in a parallel arrangement (series arrangement).
  • the interval between the upper and lower columns and the interval between the left and right columns in the drawing of the through hole are the same. Therefore, in the current collector shown in FIG. 4, straight lines (one-dot chain lines in the figure) connecting one through hole 120 and the other through hole closest to the through hole 120 exist in the vertical direction and the horizontal direction in the figure. is doing.
  • the electrode of the present invention when the current collector in which the through holes are arranged in the pattern shown in FIG.
  • the vertical direction and the horizontal direction in the figure are perpendicular to the direction in which the tab portion protrudes from the main body portion.
  • the direction of the current collector is adjusted so that it does not exist within the range of 0 ° ⁇ 20 ° from the direction or within the range of 0 ° ⁇ 20 ° from the direction parallel to the short side of the rectangular main body.
  • the arrangement of the plurality of through holes in the current collector according to the electrode of the present invention is not limited to that shown in FIGS. 2 to 4, but is regularly arranged, more specifically, a specific pattern is repeated. As long as they are arranged.
  • One type of repeated pattern may be used, or two or more types may be used.
  • the average diameter of the through-holes in the current collector is such that when the through-holes are used as Li ions (non-aqueous electrolyte containing the same), the current distribution and the electrodes are improved by the through-holes. From the standpoint of ensuring better the effect of improving the adhesion with the mixture layer, it is preferably 1 ⁇ m or more, and more preferably 50 ⁇ m or more. In addition, since the strength of the current collector may decrease if the size of the through hole is too large, the average diameter of the through holes in the current collector is preferably 400 ⁇ m or less, and more preferably 350 ⁇ m or less. preferable.
  • the average diameter of the through-holes in the current collector referred to in this specification is the tab portion of the electrode body portion of at least 20 through-holes in the field of view when the current collector is observed with a scanning electron microscope (SEM). Measure the diameter in the direction perpendicular to and parallel to the direction in which it protrudes from the main body, or the diameter in the direction parallel to and perpendicular to the short side of the rectangular main body using a scale, and calculate the average of these diameters. Is the value calculated as
  • the porosity of the current collector having a plurality of through-holes can be determined from the viewpoint of improving the flow when the through-hole is a passage for Li ions (non-aqueous electrolyte containing the same), Is preferably 3% or more, and more preferably 8% or more from the viewpoint of better ensuring the effect of enhancing the adhesion between the current collector and the electrode mixture layer.
  • the porosity of the current collector having a plurality of through holes is preferably 50% or less. More preferably, it is 45% or less.
  • the distance between one through hole in the current collector having a plurality of through holes and the other through hole closest to the through hole is 30 to It is preferable that it is 1000 micrometers.
  • the distance between the two through holes in this specification is calculated by observing the current collector with an SEM, measuring the distance between at least 40 sets of through holes in the field of view using a scale, and averaging these. It is the value.
  • the aspect ratio (b / a ratio in FIG. 1) is larger than 1.
  • the larger the aspect ratio the shorter the short side of the main body. Cracks and breaks are more likely to occur in a direction parallel to or near the direction, but with the electrode of the present invention, such cracks and breaks may occur even when the main body has an aspect ratio of 2 or more. Generation
  • production can be suppressed favorably.
  • the upper limit of the aspect ratio of the main body is usually about 10.
  • an electrode for a lithium ion secondary battery (a positive electrode for a lithium ion secondary battery or a negative electrode for a lithium ion secondary battery) which is a main embodiment of the electrode of the present invention.
  • the electrode mixture layer will be described later in the section of a lithium ion secondary battery).
  • the current collector is a punching metal made of aluminum or aluminum alloy, or an aluminum foil or aluminum alloy foil with through holes formed by etching. Can be used.
  • the thickness of the current collector is preferably 6 to 30 ⁇ m, and more preferably 6 to 20 ⁇ m from the viewpoint that the effects of the present invention are more easily exhibited.
  • the current collector used is a punching metal made of copper or copper alloy, or a copper foil or copper alloy foil with through holes formed by etching. can do.
  • the thickness of the current collector is preferably 4 to 30 ⁇ m, and more preferably 4 to 20 ⁇ m from the viewpoint that the effects of the present invention are more easily exhibited.
  • the lithium ion secondary battery of the present invention (hereinafter sometimes simply referred to as “battery”) is a laminated electrode body in which a positive electrode and a negative electrode are laminated via a separator (a wound electrode body is wound).
  • the electrode body in a state in which a positive electrode, a negative electrode, and a separator are laminated) and a nonaqueous electrolyte solution, and at least the positive electrode of the positive electrode and the negative electrode is the electrode of the present invention.
  • the negative electrode is also preferably the electrode of the present invention, although depending on the aspect of the Li supply source other than the positive electrode.
  • the electrode of the present invention can be used for the negative electrode as necessary.
  • the negative electrode has the same configuration as that of the electrode of the present invention except that the current collector has a through-hole, and the current collector is regular.
  • the positive electrode mixture layer (the electrode mixture layer when the electrode of the present invention is used as a positive electrode) according to the positive electrode of the battery of the present invention contains a positive electrode active material (electrode active material).
  • a positive electrode active material electrode active material
  • a conductive additive and a binder are included.
  • a metal oxide composed of a metal M (Co, Mn, Ni, Ti, Fe, etc.) other than Li and Li can be used. More specifically, lithium cobalt oxide such as LiCoO 2 ; lithium manganese oxide such as LiMnO 2 and Li 2 MnO 3 ; lithium nickel oxide such as LiNiO 2 ; lithium having a layered structure such as LiCo 1-x NiO 2 Containing complex oxide; lithium-containing complex oxide having a spinel structure such as LiMn 2 O 4 , Li 4/3 Ti 5/3 O 4 ; lithium-containing complex oxide having an olivine structure such as LiFePO 4 ; Examples include lithium-containing composite oxides such as oxides substituted with various elements as compositions.
  • lithium cobalt oxide such as LiCoO 2 ; lithium manganese oxide such as LiMnO 2 and Li 2 MnO 3 ; lithium nickel oxide such as LiNiO 2 ; lithium having a layered structure such as LiCo 1-x NiO 2 Containing complex oxide; lithium-containing complex oxide
  • the positive electrode mixture layer usually contains a conductive additive and a binder.
  • a conductive additive such as carbon blacks such as graphite, acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black; carbon fiber; Conductive fibers such as fibers; carbon fluoride; metal powders such as aluminum; zinc oxide; conductive whiskers such as potassium titanate; conductive metal oxides such as titanium oxide; organic conductive materials such as polyphenylene derivatives ; Can also be used.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • SBR styrene butadiene rubber
  • the thickness of the positive electrode mixture layer is preferably, for example, 10 to 100 ⁇ m per one side of the current collector.
  • the amount of the positive electrode active material is preferably 65 to 98% by mass
  • the amount of the binder is preferably 0.5 to 15% by mass
  • the conductive auxiliary agent Is preferably 0.5 to 20% by mass.
  • the positive electrode mixture layer is, for example, a paste-like or slurry-like positive electrode mixture in which a positive electrode active material, a binder, and a conductive auxiliary agent are dispersed in an organic solvent such as N-methyl-2-pyrrolidone (NMP) or a solvent such as water.
  • NMP N-methyl-2-pyrrolidone
  • Prepare an agent-containing composition (however, the binder may be dissolved in a solvent), apply it to one or both sides of the current collector, dry it, and then apply a press treatment such as calendering if necessary. It can form through the process to give.
  • the negative electrode mixture layer (the electrode mixture layer when the electrode of the present invention is used as a negative electrode) according to the negative electrode of the battery of the present invention contains a negative electrode active material (electrode active material).
  • a binder is included.
  • Examples of the negative electrode active material include graphite [natural graphite such as scale-like graphite; artificial graphite obtained by graphitizing easily graphitized carbon such as pyrolytic carbons, mesophase carbon microbeads (MCMB) and carbon fibers at 2800 ° C. or more; ], Pyrolytic carbons, cokes, glassy carbons, fired organic polymer compounds, MCMB, carbon fibers, activated carbon and other carbon materials; metals that can be alloyed with lithium (Si, Sn, etc.), and these These materials include metals (alloys, oxides, etc.), and one or more of these can be used.
  • negative electrode active materials materials containing Si and O as constituent elements (provided that the atomic ratio x of O to Si is 0.5 ⁇ x ⁇ 1.5. x ”)) is preferred. Since SiO x is a so-called high capacity negative electrode material, the capacity of the electrode (negative electrode) can be increased by using this as a negative electrode active material.
  • a negative electrode using a high-capacity negative electrode material such as SiO x greatly expands when the battery is charged, as described above, in a lithium ion secondary battery using such a negative electrode, a positive electrode or a negative electrode current collector is used.
  • the current collector is easily broken as described above.
  • the negative electrode contains a high-capacity negative electrode material such as SiO x as the negative electrode active material
  • the positive electrode current collector is broken because the electrode of the present invention is used for the positive electrode.
  • breakage of the negative electrode current collector can be suppressed well.
  • the SiO x may contain Si microcrystal or amorphous phase.
  • the atomic ratio of Si and O is a ratio including Si microcrystal or amorphous phase Si. That is, SiO x includes a structure in which Si (for example, microcrystalline Si) is dispersed in an amorphous SiO 2 matrix, and this amorphous SiO 2 is dispersed in the SiO 2 matrix. It is sufficient that the atomic ratio x satisfies 0.5 ⁇ x ⁇ 1.5 in combination with Si.
  • x 1, so that the structural formula is represented by SiO.
  • a material having such a structure for example, in X-ray diffraction analysis, a peak due to the presence of Si (microcrystalline Si) may not be observed, but when observed with a transmission electron microscope, the presence of fine Si Can be confirmed.
  • SiO x is compounded with a carbon material.
  • the surface of SiO x is preferably covered with a carbon material. Since SiO x has poor conductivity, when it is used as a negative electrode active material, from the viewpoint of securing good battery characteristics, a conductive material (conductive aid) is used, and SiO x and conductive material in the negative electrode are used. Therefore, it is necessary to form a good conductive network by mixing and dispersing with each other. If complexes complexed with carbon material SiO x, for example, simply than with a material obtained by mixing a conductive material such as SiO x and the carbon material, good conductive network in the negative electrode Formed.
  • the composite in which the surface of SiO x is coated with a carbon material is further combined with a conductive material (carbon material or the like), a better conductive network can be formed in the negative electrode.
  • a battery with higher capacity and more excellent battery characteristics (for example, charge / discharge cycle characteristics).
  • the complex of the SiO x and the carbon material coated with a carbon material for example, like granules the mixture was further granulated with SiO x and the carbon material coated with a carbon material.
  • SiO x whose surface is coated with a carbon material
  • the surface of a composite (for example, a granulated body) of SiO x and a carbon material having a smaller specific resistance value is further coated with a carbon material.
  • a carbon material for example, a granulated body
  • Those can also be preferably used.
  • a better conductive network can be formed. Therefore, in a battery having a negative electrode containing SiO x as a negative electrode active material, heavy load discharge characteristics, etc. The battery characteristics can be further improved.
  • Preferred examples of the carbon material that can be used to form a composite with SiO x include carbon materials such as low crystalline carbon, carbon nanotubes, and vapor grown carbon fibers.
  • the details of the carbon material include at least one selected from the group consisting of fibrous or coiled carbon materials, carbon black (including acetylene black and ketjen black), artificial graphite, graphitizable carbon, and non-graphitizable carbon.
  • a seed material is preferred.
  • a fibrous or coiled carbon material is preferable in that it easily forms a conductive network and has a large surface area.
  • Carbon black (including acetylene black and ketjen black), graphitizable carbon, and non-graphitizable carbon have high electrical conductivity and high liquid retention, and even if SiO x particles expand and contract. This is preferable in that it has a property of easily maintaining contact with the particles.
  • graphite can also be used as a carbon material related to a composite of SiO x and a carbon material.
  • Graphite like carbon black, has high electrical conductivity and high liquid retention. Furthermore, even if SiO x particles expand and contract, they have the property of easily maintaining contact with the particles. Therefore, it can be preferably used for forming a complex with SiO x .
  • a fibrous carbon material is particularly preferable for use when the composite with SiO x is a granulated body. Fibrous carbon material can follow the expansion and contraction of SiO x with the charging and discharging of the battery due to the high shape is thin threadlike flexibility, also because bulk density is large, many and SiO x particles It is because it can have a junction.
  • the fibrous carbon include polyacrylonitrile (PAN) -based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, and carbon nanotube, and any of these may be used.
  • the fibrous carbon material can also be formed on the surface of the SiO x particles by, for example, a vapor phase method.
  • the composite of SiO x and the carbon material may further have a material layer (a material layer containing non-graphitizable carbon) that covers the carbon material coating layer on the particle surface.
  • SiO x relative to 100 parts by mass, a carbon material
  • the amount is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more.
  • SiO x relative to 100 parts by weight, the carbon material, and more preferably preferably not more than 50 parts by weight, more than 40 parts by weight.
  • the composite of the SiO x and the carbon material can be obtained, for example, by the following method.
  • a dispersion liquid in which SiO x is dispersed in a dispersion medium is prepared, and sprayed and dried to produce composite particles including a plurality of particles.
  • a dispersion medium for example, ethanol or the like can be used as the dispersion medium. It is appropriate to spray the dispersion liquid in an atmosphere of 50 to 300 ° C.
  • similar composite particles can be produced also by a granulation method by a mechanical method using a vibration type or planetary type ball mill or rod mill.
  • the SiO x in the case of manufacturing a granulated body with small carbon material resistivity value than SiO x is adding the carbon material in the dispersion liquid of SiO x are dispersed in a dispersion medium, the dispersion by using a liquid, by a similar method to the case of composite of SiO x may be a composite particle (granule). Further, by granulation process according to the similar mechanical method, it is possible to produce a granular material of the SiO x and the carbon material.
  • SiO x particles SiO x composite particles or a granulated body of SiO x and a carbon material
  • a carbon material for example, the SiO x particles and the hydrocarbon-based material
  • the gas is heated in the gas phase, and carbon generated by pyrolysis of the hydrocarbon-based gas is deposited on the surface of the particles.
  • the hydrocarbon-based gas spreads to every corner of the composite particle, and the surface of the particle and the pores in the surface are thin and contain a conductive carbon material. Since a uniform film (carbon material coating layer) can be formed, the SiO x particles can be imparted with good conductivity with a small amount of carbon material.
  • the processing temperature (atmosphere temperature) of the vapor deposition (CVD) method varies depending on the type of hydrocarbon gas, but usually 600 to 1200 ° C. is appropriate. Among these, the temperature is preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. This is because the higher the treatment temperature, the less the remaining impurities, and the formation of a coating layer containing carbon having high conductivity.
  • liquid source of hydrocarbon gas toluene, benzene, xylene, mesitylene and the like can be used, but toluene that is easy to handle is particularly preferable.
  • a hydrocarbon-based gas can be obtained by vaporizing them (for example, bubbling with nitrogen gas).
  • methane gas, acetylene gas, etc. can also be used.
  • SiO x particles SiO x composite particles or a granulated body of SiO x and a carbon material
  • a carbon material by a vapor deposition (CVD) method
  • a petroleum-based pitch or a coal-based pitch is used.
  • At least one organic compound selected from the group consisting of a thermosetting resin and a condensate of naphthalene sulfonate and aldehydes is attached to a coating layer containing a carbon material, and then the organic compound is attached.
  • the obtained particles may be fired.
  • a dispersion liquid in which a SiO x particle (SiO x composite particle or a granulated body of SiO x and a carbon material) coated with a carbon material and the organic compound are dispersed in a dispersion medium is prepared, The dispersion is sprayed and dried to form particles coated with the organic compound, and the particles coated with the organic compound are fired.
  • Isotropic pitch can be used as the pitch, and phenol resin, furan resin, furfural resin, or the like can be used as the thermosetting resin.
  • phenol resin, furan resin, furfural resin, or the like can be used as the thermosetting resin.
  • condensate of naphthalene sulfonate and aldehydes naphthalene sulfonic acid formaldehyde condensate can be used.
  • a dispersion medium for dispersing the SiO x particles coated with the carbon material and the organic compound for example, water or alcohols (ethanol or the like) can be used. It is appropriate to spray the dispersion liquid in an atmosphere of 50 to 300 ° C.
  • the firing temperature is usually 600 to 1200 ° C., preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. This is because the higher the processing temperature, the less the remaining impurities, and the formation of a coating layer containing a high-quality carbon material with high conductivity. However, the processing temperature needs to be lower than the melting point of SiO x .
  • SiO x When SiO x is used for the negative electrode active material, only SiO x may be used, or SiO x and the negative electrode active material may be used in combination. When SiO x and other negative electrode active materials are used in combination, among the various negative electrode active materials exemplified above, materials other than SiO x can be used as the other negative electrode active materials.
  • graphite materials such as highly crystalline natural graphite and artificial graphite are preferable. When natural graphite is used, heat treatment may be performed at a higher temperature, artificial graphite fine particles (granular, flat, etc.) may be coated, or an organic substance such as a resin may be coated.
  • the proportion of SiO x is 5% by mass or more from the viewpoint of increasing the capacity of the battery. It is preferably 10% by mass or more. Even when SiO x is used in a relatively large proportion as described above, since the positive electrode is the electrode of the present invention, it is possible to suppress breakage of the positive electrode current collector due to charge / discharge of the battery, When the electrode of the present invention is used as a negative electrode, breakage of the negative electrode current collector accompanying charging / discharging of the battery can be suppressed.
  • the ratio of SiO x when the total of all the negative electrode active materials is 100% by mass may be 100% by mass.
  • the charge / discharge cycle characteristics of the battery can be further enhanced by using a graphite material or the like in this case.
  • the ratio of SiO x when the total of all the negative electrode active materials is 100% by mass. Is preferably 95% by mass or less, and more preferably 85% by mass or less.
  • PVDF polyvinylpyrrolidone
  • SBR carboxymethylcellulose
  • PVP polyvinylpyrrolidone
  • polyamideimide polyimide
  • polyamide polyamide
  • R in the formula (2) represents hydrogen or a methyl group
  • M 1 represents an alkali metal element such as sodium, potassium, or lithium
  • the negative electrode mixture layer can also contain a conductive additive.
  • a conductive additive The same thing as what was illustrated previously as what can be used for a positive mix layer can be used for the conductive support agent which concerns on a negative mix layer.
  • the thickness of the negative electrode mixture layer is preferably, for example, 10 to 100 ⁇ m per one side of the current collector.
  • the amount of the negative electrode active material is preferably 85 to 95% by mass
  • the amount of the binder is preferably 1 to 15% by mass
  • a conductive assistant is used. In that case, the amount is preferably 1 to 10% by mass.
  • the negative electrode mixture layer is, for example, a paste-like or slurry-like negative electrode mixture-containing composition in which a negative electrode active material and a binder, and further a conductive auxiliary agent, if necessary, are dispersed in an organic solvent such as NMP or a solvent such as water. (However, the binder may be dissolved in a solvent), and this is applied to one or both sides of the current collector, dried, and then subjected to pressing treatment such as calendering as necessary. It can be formed through.
  • the lithium ion secondary battery of the present invention when a material having a high capacity and a large irreversible capacity such as SiO x is used for the negative electrode active material, it is released from the positive electrode (positive electrode active material) by the initial charge of the battery. Since relatively many of the Li ions cannot return to the positive electrode at the next discharge, there is a possibility that the capacity that the positive electrode originally has cannot be sufficiently extracted. Therefore, in the lithium ion secondary battery of the present invention, when a negative electrode active material having a large irreversible capacity such as SiO x is used, an Li supply source (Li for pre-doping) is used to fill the irreversible capacity during assembly. It is preferable to have a supply source) separately from the positive electrode.
  • Li supply source Li for pre-doping
  • Li supply source examples include Li metal foil and Li alloy foil (hereinafter collectively referred to as “Li foil”) and the like, and can be in contact with any part of the battery outer body (non-aqueous electrolyte solution).
  • This Li supply source may be arranged at a certain point. Specifically, for example, a Li electrode formed by attaching a Li foil as a Li supply source to a metal foil such as a copper foil as a current collector can be used. By being electrically connected, the Li electrode Li foil functions as a Li supply source.
  • the amount of Li supply source to be introduced (the amount of Li contained in the Li supply source) is set to 0.
  • the molar ratio Li / M of Li and metal M contained in the positive electrode active material is, for example, the following value: It is preferable to adjust.
  • the proportion of SiO x in the total amount of the negative electrode active material contained in the negative electrode mixture layer is 5 to 10% by mass, the molar ratio Li / M is preferably 0.9 to 1.05.
  • the molar ratio Li / M is preferably 0.8 to 0.9, and the SiO x ratio is preferably 60 to 100%. In the case of mass%, the molar ratio Li / M is preferably 0.6 to 0.8.
  • the Li supply source (the Li foil) is incorporated into the negative electrode active material in order to fill the irreversible capacity of the negative electrode active material.
  • the battery is a battery in which a negative electrode active material is pre-doped by introducing a Li supply source.
  • the molar ratio Li / M does not vary greatly after the discharge in the first charge / discharge. Therefore, in a battery that has passed the number of charge / discharge cycles of about 100 cycles or less, when the molar ratio Li / M satisfies the above value, a Li supply source is introduced at the time of battery assembly and the negative electrode active material is pre-doped. Can be considered.
  • a porous film composed of a resin such as polyolefin, polyester, polyimide, polyamide, polyurethane can be used.
  • a resin such as polyolefin, polyester, polyimide, polyamide, polyurethane
  • polyolefin is used. It is preferred to use a porous membrane made of
  • polystyrene resin examples include polyethylene (PE) such as low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene; polypropylene (PP); etc., and only one of these may be used. You may use together.
  • PE polyethylene
  • PP polypropylene
  • a porous film using two or more kinds of polyolefin for example, a porous film having a three-layer structure in which a PP layer is laminated on a PP layer via a PE layer can be mentioned.
  • polyolefins those having a melting point, that is, a melting temperature measured by DSC of 80 to 150 ° C., in accordance with JIS K 7121 are preferably used.
  • a porous film containing a polyolefin having such a melting point can be a separator having a shutdown characteristic starting temperature of 90 to 150 ° C. in which the polyolefin is softened and the pores of the separator are closed. By using the separator, it is possible to further improve the safety of the battery.
  • porous membranes used in separators include ion-permeable porous membranes having a large number of pores formed by a conventionally known solvent extraction method, dry type or wet drawing method (generally used as battery separators). A microporous film) can be used.
  • a laminated separator in which a heat-resistant porous layer containing a heat-resistant inorganic filler is formed on the surface of the porous film (microporous film) may be used.
  • a stacked separator When such a stacked separator is used, the shrinkage of the separator is suppressed even when the temperature in the battery rises, and a short circuit due to contact between the positive electrode and the negative electrode can be suppressed. A high lithium ion secondary battery can be obtained.
  • boehmite As the inorganic filler to be contained in the heat-resistant porous layer, boehmite, alumina, silica, titanium oxide and the like are preferable, and one or more of these can be used.
  • the heat-resistant porous layer preferably contains a binder for binding the inorganic fillers or bonding the heat-resistant porous layer and the microporous film.
  • the binder includes an ethylene-vinyl acetate copolymer (EVA, having a structural unit derived from vinyl acetate of 20 to 35 mol%), an ethylene-acrylic acid copolymer such as an ethylene-ethyl acrylate copolymer, and a fluorine-based rubber.
  • Styrene butadiene rubber SBR
  • CMC carboxymethyl cellulose
  • HEC hydroxyethyl cellulose
  • PVA polyvinyl alcohol
  • PVB polyvinyl butyral
  • PVP polyvinyl pyrrolidone
  • cross-linked acrylic resin polyurethane, epoxy resin, etc.
  • the content of the inorganic filler in the heat-resistant porous layer is preferably 50% by volume or more in the entire volume of the components constituting the heat-resistant porous layer (in the entire volume excluding the pores), 70 It is more preferable that the volume is not less than volume%, and it is more preferable that the volume be not more than 99 volume% (the remainder may be the above binder).
  • the thickness of the separator (a separator made of a microporous membrane made of polyolefin, or the laminated separator) is to reduce the occupancy of the battery internal volume of components that are not involved in the battery reaction and increase the amount of active material of the positive and negative electrodes From the viewpoint of increasing the design capacity and output density of the battery, it is preferably 30 ⁇ m or less, and more preferably 16 ⁇ m or less. However, from the viewpoint of sufficiently maintaining the strength of the separator, the thickness of the separator is preferably 5 ⁇ m or more, and more preferably 10 ⁇ m or more.
  • the heat-resistant porous layer preferably has a thickness of 3 to 8 ⁇ m.
  • the porosity of the heat resistant porous layer is preferably 40 to 70%.
  • non-aqueous electrolyte solution for the non-aqueous electrolyte solution according to the battery of the present invention, a solution prepared by dissolving a lithium salt in the following non-aqueous solvent can be used.
  • solvent examples include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ⁇ -butyrolactone ( ⁇ -BL ), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, dimethyl sulfoxide (DMSO), 1,3-dioxolane, formamide, dimethylformamide (DMF), dioxolane, acetonitrile, nitromethane, Methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, di Chirueteru, can be an aprotic organic solvent such as 1,3-propane
  • the lithium salt according to the non-aqueous electrolyte solution for example, LiClO 4, LiPF 6, LiBF 4, LiAsF 6, LiSbF 6, LiCF 3 SO 3, LiCF 3 CO 2, Li 2 C 2 F 4 (SO 3) 2, At least 1 selected from LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (n ⁇ 2), LiN (RfOSO 2 ) 2 [where Rf is a fluoroalkyl group] Species are mentioned.
  • the concentration of these lithium salts in the non-aqueous electrolyte is preferably 0.6 to 1.8 mol / l, and more preferably 0.9 to 1.6 mol / l.
  • Additives such as dinitrile, 1,3-propane sultone, diphenyl disulfide, cyclohexylbenzene, biphenyl, fluorobenzene, and t-butylbenzene can be added as appropriate.
  • non-aqueous electrolyte a gel (gel electrolyte) obtained by adding a known gelling agent such as a polymer can be used.
  • the lithium ion secondary battery of the present invention can be used as an outer can such as a steel can or an aluminum can, or as a soft package battery using a laminate film deposited with a metal as an outer casing.
  • Example 1 Preparation of positive electrode> LiCoO 2 as a positive electrode active material: 96.5 parts by mass, NMP solution containing PVDF as a binder at a concentration of 10% by mass: 20 parts by mass, and acetylene black as a conductive auxiliary agent: 1.5 parts by mass
  • NMP was added to adjust the viscosity to prepare a positive electrode mixture-containing paste.
  • this paste is applied to one or both sides of a 15 ⁇ m thick aluminum foil having a plurality of through-holes and vacuum-dried at 120 ° C. for 12 hours to form a positive electrode mixture on one or both sides of the aluminum foil.
  • a layer was formed, pressed, and cut to a predetermined size to obtain a strip-like positive electrode.
  • the positive electrode mixture-containing paste when applying the positive electrode mixture-containing paste to the aluminum foil, a part of the aluminum foil is exposed, and the positive electrode mixture-containing paste is applied to both sides of the aluminum foil. The applied part was also made into the application part.
  • the thickness of the positive electrode mixture layer of the obtained positive electrode was 55 ⁇ m.
  • FIG. 1 is a plan view schematically showing the battery positive electrode (however, in order to facilitate understanding of the structure of the positive electrode, the size of the positive electrode shown in FIG.
  • the positive electrode 10 has a shape having a tab portion 13 punched out so that a part of the exposed portion of the positive electrode current collector 12 protrudes, and the shape of the main body portion where the positive electrode mixture layer 11 is formed is curved at the four corners.
  • the lengths a, b and c in the figure were 5 mm, 30 mm and 2 mm, respectively.
  • This battery positive electrode had an aspect ratio of 6.
  • the positive electrode current collector is provided with through holes having a hole diameter of 150 ⁇ m in a staggered arrangement shown in FIG. 2 (hereinafter referred to as “pattern A”), and the positive electrode current collector has a porosity of 17%.
  • pattern A a staggered arrangement shown in FIG. 2
  • the positive electrode current collector has a porosity of 17%.
  • the distance between one through hole 120 and the six through holes closest to the through hole 120 is 400 ⁇ m.
  • two diagonal lines in the figure are parallel to the short side of the main body (the direction in which the tab portion protrudes from the main body).
  • the negative electrode mixture-containing paste is applied to both sides of a 10 ⁇ m thick copper foil having a plurality of through holes and dried to form a negative electrode mixture layer on both sides of the copper foil, followed by press treatment. Then, after adjusting the density of the negative electrode mixture layer to 1.56 g / cm 3 , the negative electrode mixture layer was cut at a predetermined size to obtain a strip-shaped negative electrode.
  • coating the negative mix containing paste to copper foil a part of copper foil was exposed and the back surface also made the application part the part made into the application part on the surface.
  • the thickness of the negative electrode mixture layer of the obtained negative electrode was 65 ⁇ m.
  • FIG. 5 is a plan view schematically showing the battery negative electrode (however, in order to facilitate understanding of the structure of the negative electrode, the size of the negative electrode shown in FIG. 5 does not necessarily match the actual one).
  • the negative electrode 20 has a shape having a tab part 23 punched out so that a part of the exposed part of the negative electrode current collector 22 protrudes, and the shape of the main body part where the negative electrode mixture layer 21 is formed is curved at the four corners.
  • the lengths d, e, and f in the figure were 6 mm, 31 mm, and 2 mm, respectively.
  • This battery negative electrode had an aspect ratio of 5.2.
  • the negative electrode current collector is provided with through holes having a hole diameter of 150 ⁇ m in the pattern A arrangement (however, in FIG. 5, the through holes are shown in the tab portion 23 which is the exposed portion of the current collector 22).
  • the porosity of the negative electrode current collector is 35%, and the distance between one through hole 120 and the six through holes closest to the through hole 120 is 180 ⁇ m.
  • two diagonal lines in the drawing are parallel to the short side of the main body (the direction in which the tab portion protrudes from the main body).
  • Li electrode for Li supply source Using a Thomson blade used in the production of the negative electrode, a 6 ⁇ m thick copper foil was punched into the same shape as the negative electrode for the battery, and a Li metal foil having a width of 3 mm, a length of 25 mm, and a thickness of 230 ⁇ m was prepared. A Li electrode for Li supply source was produced by pressure bonding on one side.
  • the negative electrode for a battery having a negative electrode mixture layer formed on both sides thereof and the positive electrode for a battery having a positive electrode mixture layer formed on both sides of the positive electrode current collector are alternately arranged, and a PE made between each positive electrode and each negative electrode.
  • a separator (thickness 16 ⁇ m) was interposed.
  • Li electrodes for a Li supply source were prepared, and the respective Li electrodes were stacked on the upper and lower ends of the laminate through PE separators (thickness: 16 ⁇ m). In addition, each Li electrode was arrange
  • All positive electrode tab portions of the laminate were collected and welded, and all negative electrode tab portions and all Li electrode tab portions were collected and welded to obtain a laminated electrode body.
  • the said laminated electrode body is inserted in the said hollow of the aluminum laminate film of thickness: 0.15mm, width: 34mm, and height: 50mm which formed the hollow so that the said laminated electrode body might be accommodated, and said and above An aluminum laminate film of the same size was placed and three sides of both aluminum laminate films were heat-welded.
  • LiPF 6 is dissolved at a concentration of 1 mol / l in a non-aqueous electrolyte (a mixed solvent having a volume ratio of EC and DEC of 3: 7), and 3 mass of vinylene carbonate is further added. % Added solution) was injected. Thereafter, the remaining one side of both aluminum laminate films was vacuum-sealed to produce a lithium ion secondary battery having the appearance shown in FIG. 6 and the cross-sectional structure shown in FIG. The prepared battery was stored at room temperature for 2 weeks for pre-doping of Li into the negative electrode.
  • a non-aqueous electrolyte a mixed solvent having a volume ratio of EC and DEC of 3: 7
  • FIG. 7 is a plan view schematically showing a lithium ion secondary battery
  • FIG. 7 is a cross-sectional view taken along the line II of FIG.
  • a lithium ion secondary battery 100 includes a laminated electrode body 102 formed by laminating a positive electrode and a negative electrode through a separator in an aluminum laminated film outer package 101 composed of two aluminum laminated films, a nonaqueous electrolytic solution (Not shown) is housed, and the aluminum laminate film outer package 101 is sealed by heat-sealing the upper and lower aluminum laminate films at the outer peripheral portion thereof.
  • the layers constituting the aluminum laminate film outer package 101 and the positive electrode, the negative electrode, the separator, and the Li electrode constituting the laminated electrode body are distinguished. Not shown.
  • Each positive electrode of the laminated electrode body 102 is integrated by welding the tab portions together, and the integrated product of the welded tab portions is connected to the positive electrode external terminal 103 in the battery 100, although not shown.
  • Each negative electrode and Li electrode of the laminated electrode body 102 are also integrated by welding the tab portions, and the integrated product of the welded tab portions is connected to the negative electrode external terminal 104 in the battery 100.
  • the positive electrode external terminal 103 and the negative electrode external terminal 104 are drawn out to the outside of the aluminum laminate film exterior body 101 so that they can be connected to an external device or the like.
  • Example 2 The positive electrode current collector is provided with through holes having a hole diameter of 150 ⁇ m in the staggered arrangement shown in FIG. 3 (hereinafter referred to as “pattern B”), and the porosity is 17%. The distance from the nearest through hole to this is changed to 380 ⁇ m, and the positive electrode current collector is changed so that the straight line indicated by the alternate long and short dash line in FIG.
  • a positive electrode for a battery was produced in the same manner as in Example 1 except that the portion was disposed at 90 ° from the direction perpendicular to the direction protruding from the main body. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Example 3 The positive electrode current collector is provided with through holes having a hole diameter of 150 ⁇ m in the parallel arrangement shown in FIG. 3 (hereinafter referred to as “pattern C”), and the porosity is 17%. The distance between the through hole closest to this is changed to 370 ⁇ m, and the two straight lines indicated by the alternate long and short dash line in the figure of this positive electrode current collector are parallel to the short side of the main body part, respectively.
  • a positive electrode for a battery was produced in the same manner as in Example 1 except that the film was disposed at 45 ° from the vertical direction (the direction perpendicular to the direction in which the tab portion protrudes from the main body portion). And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Example 4 The positive electrode current collector is provided with through holes having a hole diameter of 150 ⁇ m arranged in the pattern A, the porosity is 35%, and the distance between one through hole 120 and the closest through hole A positive electrode for a battery was produced in the same manner as in Example 1 except that the thickness was changed to 180 ⁇ m. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Example 5 In the direction of the negative electrode current collector, one of the three straight lines shown in FIG. 2 is parallel to the short side of the main body (the direction perpendicular to the direction in which the tab protrudes from the main body). The remaining two are arranged so as to be 30 ° from the direction parallel to the short side of the main body (the direction perpendicular to the direction in which the tab portion protrudes from the main body), and the first embodiment.
  • a negative electrode for a battery was produced. And the lithium ion secondary battery was produced like Example 1 except having used the said negative electrode for batteries.
  • Example 6 The positive electrode current collector is provided with through holes having a hole diameter of 150 ⁇ m arranged in the pattern A, the porosity is 50%, and the distance between one through hole 120 and the closest through hole A positive electrode for a battery was produced in the same manner as in Example 1 except that the thickness was changed to 100 ⁇ m. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Example 7 The positive electrode current collector is provided with through holes having a hole diameter of 450 ⁇ m arranged in the pattern A, the porosity is 25%, and the distance between one through hole 120 and the closest through hole A positive electrode for a battery was produced in the same manner as in Example 1 except that the thickness was changed to 800 ⁇ m. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Comparative Example 1 The direction of the positive electrode current collector is such that one of the three straight lines shown in FIG. 2 is parallel to the short side of the main body (the direction perpendicular to the direction in which the tab protrudes from the main body). The remaining two are arranged so as to be 30 ° from the direction parallel to the short side of the main body (the direction perpendicular to the direction in which the tab portion protrudes from the main body), and the first embodiment.
  • a positive electrode for a battery was produced. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Comparative Example 2 The positive electrode current collector is provided with through holes having a hole diameter of 350 ⁇ m arranged in the pattern A, the porosity is 17%, and the distance between one through hole 120 and the closest through hole A positive electrode for a battery was produced in the same manner as in Comparative Example 1 except that the thickness was changed to 900 ⁇ m. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Comparative Example 3 The direction of the positive electrode current collector is arranged so that the straight line indicated by the alternate long and short dash line in FIG. 3 is parallel to the short side of the main body (the direction perpendicular to the direction in which the tab portion protrudes from the main body).
  • a battery positive electrode was produced in the same manner as Example 2 except for the above.
  • the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Comparative Example 4 The direction of the positive electrode current collector is such that one of the two straight lines shown in FIG. 4 is parallel to the short side of the main body (the direction perpendicular to the direction in which the tab protrudes from the main body). And the remaining one is arranged so as to be 90 ° from the direction parallel to the short side of the main body (the direction perpendicular to the direction in which the tab portion protrudes from the main body), as in Example 3.
  • a positive electrode for a battery was produced. And the lithium ion secondary battery was produced like Example 1 except having used the said battery positive electrode.
  • Tables 1 and 2 show the configurations of the positive electrode current collector and the negative electrode current collector in each of the lithium ion secondary batteries of Examples and Comparative Examples, and Table 3 shows the evaluation results.
  • the “angle” in Tables 1 and 2 is the direction parallel to the short side of the main body portion of the straight line between one through hole and the other through hole closest to the through hole (the tab portion is the main body portion). It means the angle from the direction perpendicular to the direction protruding from.
  • the lithium ion secondary batteries of Examples 1 to 7 using the positive electrode with the proper arrangement of the through-holes in the current collector were collected in the main body of the positive electrode after the charge / discharge cycle.
  • the occurrence of breakage of the body was suppressed, and it had high reliability.
  • the positive electrodes used in the lithium ion secondary batteries of Examples 1 to 7 the occurrence of breakage of the tab portion was well suppressed by welding during the production of the laminated electrode body.
  • the positive electrodes according to Examples 1 to 5 in which the porosity of the current collector was more favorable the occurrence of cracks in the tab portion was also well suppressed.
  • the batteries of Comparative Examples 1 to 4 using the positive electrode in which the arrangement of the through holes in the current collector was inadequate were inferior in reliability because the positive electrode current collector was broken after the charge / discharge cycle.
  • the positive electrode used in these batteries was inferior in reliability due to the occurrence of breakage in the current collector during welding during the production of the laminated electrode body.
  • the lithium ion secondary battery of the present invention can be applied to the same applications as various applications to which conventionally known lithium ion secondary batteries are applied.

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Abstract

L'invention concerne : une électrode pour éléments électrochimiques, qui présente une excellente fiabilité; et une pile rechargeable lithium-ion qui comprend cette électrode. L'électrode pour éléments électrochimiques selon la présente invention comprend : une partie corps principal qui comporte une couche de mélange d'électrode contenant un matériau actif d'électrode sur une surface ou les deux surfaces d'un collecteur; et une partie languette qui ne comporte pas de couche de mélange d'électrode sur les deux surfaces du collecteur. Le collecteur comporte une pluralité de trous traversants qui pénètrent à travers lui d'une surface à l'autre surface, et la pluralité de trous traversants sont agencés régulièrement. Il n'existe aucune ligne droite reliant un trou traversant et un autre trou traversant qui est le plus proche de ce trou traversant dans la plage de 0° ± 20° par rapport à la direction qui est perpendiculaire à la direction dans laquelle la partie languette fait saillie de la partie corps principal, ou, selon une variante, la partie corps principal présente une forme rectangulaire et il n'existe aucune ligne droite reliant un trou traversant dans le collecteur et un autre trou traversant qui est le plus proche de ce trou traversant dans la plage de 0° ± 20° par rapport à la direction qui est parallèle aux petits côtés de la partie corps principal. Une pile rechargeable lithium-ion selon la présente invention comprend au moins une électrode positive qui est composée de cette électrode.
PCT/JP2016/084217 2015-11-30 2016-11-18 Électrode pour éléments électrochimiques, et pile rechargeable lithium-ion WO2017094526A1 (fr)

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