WO2013001792A1 - Electrode plate for electrochemical element, method for manufacturing electrode plate for electrochemical element, and electrochemical element - Google Patents
Electrode plate for electrochemical element, method for manufacturing electrode plate for electrochemical element, and electrochemical element Download PDFInfo
- Publication number
- WO2013001792A1 WO2013001792A1 PCT/JP2012/004127 JP2012004127W WO2013001792A1 WO 2013001792 A1 WO2013001792 A1 WO 2013001792A1 JP 2012004127 W JP2012004127 W JP 2012004127W WO 2013001792 A1 WO2013001792 A1 WO 2013001792A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- electrode
- active material
- electrode plate
- electrode lead
- electrochemical element
- Prior art date
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Images
Classifications
-
- 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
- H01M10/058—Construction or manufacture
- H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
-
- 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
- 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
- H01G11/74—Terminals, e.g. extensions of current collectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/008—Terminals
-
- 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
- H01M10/04—Construction or manufacture in general
- H01M10/0431—Cells with wound or folded electrodes
-
- 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
- H01M10/04—Construction or manufacture in general
- H01M10/0436—Small-sized flat cells or batteries for portable equipment
-
- 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
-
- 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
- H01M10/34—Gastight accumulators
- H01M10/345—Gastight metal hydride accumulators
-
- 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
- H01M50/54—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to an electrode plate for an electrochemical element, a method for manufacturing the same, and an electrochemical element, and more particularly, to an improved bonding state between an electrode plate and an electrode lead.
- Such electrochemical devices such as secondary batteries and capacitors have a pair of electrode plates with different polarities inside, and the electrode plates are electrically connected via external terminals such as sealing plates and electrode leads. Connected to.
- the electrode plate usually has a structure in which active material layers are formed on both surfaces of a metal foil as a current collector.
- the electrode plate having such a structure is provided with a current collector exposed portion on which an active material layer is not formed at an appropriate interval in order to connect strip-shaped metal pieces as electrode leads. .
- the electrical connection between the electrode plate and the electrode lead is conventionally performed by connecting the current collector and the electrode lead. This is because if it is attempted to connect the electrode plate and the electrode lead through the active material layer, it is difficult to ensure sufficient electrical connection.
- the current collector exposed portion (that is, the uncoated portion of the active material layer) is prepared without applying the electrode slurry containing the active material, or formed after the electrode slurry is applied, for example. It is manufactured by removing a part of the film (see Patent Document 1 and Patent Document 2).
- the electrode slurry is intermittently applied to the current collector surface, or the electrode slurry is continuously applied. After coating, by removing a part of the formed coating film, an uncoated portion of the active material layer for connecting the electrode leads can be easily formed. However, the width of the uncoated portion needs to be larger than the width of the electrode lead. Therefore, the amount of the active material is reduced due to the presence of the uncoated portion, which is an obstacle to increase the capacity.
- the melted portion formed by welding between the current collector exposed portion and the electrode lead includes an alloy of the metal component of the electrode lead and the metal component of the current collector.
- the alloy of the metal component of an electrode lead and an active material is not included.
- the size of the melted part is small.
- the active material is not melted, an active material layer exists between the current collector and the electrode lead, and the bonding area between the current collector and the electrode lead becomes very small. As a result, the welding strength is reduced, and there is a problem that the fracture of the melted portion tends to occur after welding.
- An object of the present invention is to provide an electrode plate for an electrochemical element in which an electrode plate body and an electrode lead are bonded with high strength, a method for manufacturing the same, and an electrochemical element.
- One aspect of the present invention is an electrode plate body including a laminate of a strip-shaped current collector containing a metal and an active material layer formed on the surface of the current collector, and a part of the active material layer
- the electrode lead including the metal disposed on the surface of the electrode, and at one end of the electrode plate body, the electrode plate body and the electrode lead are provided with a melting portion that electrically connects, and the melting portion includes at least an active material
- the present invention also relates to an electrode plate for an electrochemical element including an alloy with a metal component of an electrode lead.
- Another aspect of the present invention is a step of preparing an electrode plate body including a laminate of a band-shaped current collector containing a metal and an active material layer formed on the surface of the current collector and containing an active material; In the step of arranging the electrode lead so that one end of the electrode plate main body and one end of the electrode lead containing metal are close to a part of the surface of the active material layer, and one end of the electrode plate main body, At least the end surface of the active material layer and the end surface of the electrode lead are welded to at least contain an alloy of at least the active material and the metal component of the electrode lead, and the electrode plate body and the electrode lead are electrically connected. And a step of forming a melted portion.
- the method of manufacturing an electrode plate for an electrochemical element In the step of arranging the electrode lead so that one end of the electrode plate main body and one end of the electrode lead containing metal are close to a part of the surface of the active material layer, and one end of the electrode plate main body, At least the end surface of the active material
- Still another aspect of the present invention is the above-described electrode plate for an electrochemical element as a first electrode, a second electrode having a polarity opposite to the first electrode, and between the first electrode and the second electrode.
- the present invention relates to an electrochemical element including a separator interposed between the two.
- the molten portion is at least active. It includes an alloy of the material and the metal component of the electrode lead.
- FIG. 1 is a cross-sectional view schematically showing a configuration of an electrode plate for an electrochemical element according to an embodiment of the present invention.
- FIG. 2 is a perspective view schematically showing a configuration of the electrode plate for an electrochemical element in FIG.
- FIG. 3 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element and a separator according to an embodiment of the present invention.
- FIG. 4 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element and a separator according to an embodiment of the present invention.
- FIG. 5 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element according to another embodiment of the present invention.
- FIG. 6 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element according to still another embodiment of the present invention.
- FIG. 7 is a schematic cross-sectional view showing a conventional electrode plate for an electrochemical element.
- FIG. 8 is a schematic cross-sectional view showing a conventional electrode plate for an electrochemical element.
- FIG. 9 is a longitudinal sectional view schematically showing a nonaqueous electrolyte secondary battery according to an embodiment of the present invention.
- FIG. 10 is an X-ray diffraction spectrum at a specific position of the melted portion in the electrode plate for an electrochemical element of Example 1.
- An electrode plate for an electrochemical device includes an electrode plate body including a laminate of a strip-shaped current collector containing metal and an active material layer formed on the surface of the current collector and containing an active material, and an active material
- An electrode lead including a metal disposed on a part of the surface of the layer, and a melting portion that electrically connects the electrode plate main body and the electrode lead at one end of the electrode plate main body.
- the melting part includes at least an alloy of the active material and the metal component of the electrode lead.
- FIG. 1 is a schematic cross-sectional view showing a configuration of an electrode plate for an electrochemical element according to an embodiment of the present invention.
- FIG. 2 is a perspective view schematically showing a configuration of the electrode plate for an electrochemical element in FIG.
- the electrode plate body 1 includes a laminate of a strip-shaped current collector 1b containing metal, such as a metal foil, and an active material layer 1a formed on both surfaces of the current collector 1b.
- the active material layer 1a is formed over the entire surface of the current collector 1b. However, the active material layer 1a is not formed on the end face of the current collector 1b, and the current collector 1b is exposed.
- An electrode lead 2 containing a metal such as a metal foil is adjacent to one end of the electrode plate main body 1 and one end of the electrode lead 2 on a part of the surface of one active material layer 1 a of the electrode plate main body 1.
- a melting portion 3 including an alloy of at least an active material and a metal component of the electrode lead 2 among the constituent components of the electrode plate main body 1 is formed.
- the melting part 3 physically connects and electrically joins the electrode plate body 1 and the electrode lead 2 at one end of the electrode plate body 1.
- the melting part 3 is formed at one end of the electrode lead 2 in the longitudinal direction.
- the electrode lead 2 is connected to an external terminal or the like.
- the thickness of the melted portion 3 in the thickness direction of the laminated body is equal to or greater than the total thickness of the laminated body and the electrode lead 2.
- the electrode plate body 1 includes a laminate of a strip-shaped current collector 1b containing metal and an active material layer 1a formed on both surfaces of the current collector 1b.
- An electrode lead 2 containing a metal is disposed on a part of the surface of one active material layer 1a of the electrode plate body 1 so that one end portion of the electrode plate body 1 and one end portion of the electrode lead 2 are close to each other.
- the one end portion of the electrode plate main body 1 is formed with a melting portion 3a formed by welding the end surface of the current collector 1b and the end surface of the electrode lead 2.
- melting part 3a is formed in the one end part of the longitudinal direction of the electrode lead 2 similarly to the case of FIG.
- the melting part 3a is merely formed by melting the end face of the current collector 1b and the end face of the electrode lead 2, it does not contain an alloy of the active material and the metal component of the electrode lead. Further, since the melting amount of the constituent components of the current collector 1b and the electrode lead 2 is small, the size of the melting portion 3a is reduced. Therefore, the thickness of the melted part 3 a in the thickness direction of the laminated body does not exceed the total thickness of the laminated body and the electrode lead 2. In such a method, as shown in FIG. 7, the melting part 3 a is sandwiched between the current collector 1 b and the electrode lead 2 so as to bridge the end surface of the current collector 1 b and the end surface of the electrode lead 2.
- FIG. 8 is a schematic cross-sectional view showing a conventional electrode plate for an electrochemical element.
- the electrode plate body 1 includes a laminate of a current collector 1b and an active material layer 1a formed on both surfaces of the current collector 1b, as in FIG. At one end of the electrode plate main body 1, a melted part 3 b formed by welding the end face of the current collector 1 b and the end face of the electrode lead 2 is formed. In FIG. 8, the thickness of the melted part 3b in the thickness direction of the laminated body becomes larger than the thickness of the laminated body by mainly melting the electrode lead 2 so that the amount of melting of the electrode lead 2 is increased. Yes.
- the electrode lead 2 is mainly melted, the active material having a high melting temperature is difficult to melt and is not alloyed. Therefore, even if the thickness of the melted part 3b is increased so that the entire end face of the laminate can be covered at one end of the electrode plate body, the electrode lead 2 is formed only on the end face of the laminate (especially the active material layer) In addition, it is difficult to increase the bonding strength because it is in a state of being joined to the electrode plate body 1 via the melted portion 3b formed in a state of being in contact with only the end surface of the active material layer.
- the melting part is formed by welding at least one end face of the active material layer and one end face of the electrode lead at one end of the electrode plate body.
- the end surface of the active material layer is mainly melted, the active material contained in the active material layer is easily melted, and the elements contained in the active material are contained in the electrode lead or the current collector. can do.
- melting of the electrode lead and the current collector can be promoted, so that the melting efficiency between the active material and the metal component of the electrode lead and the melting efficiency of the current collector and the metal component of the electrode lead can be increased. it can.
- the size of the melted portion increases as shown in FIG. 1 and FIG.
- the thickness of the melted portion is increased to be equal to or greater than the total thickness of the laminate and the electrode lead. That is, the active material and the constituent components of the electrode lead are alloyed to form a melted portion, and at one end of the electrode plate body, the entire end surface of the laminate is covered with the melted portion in the thickness direction of the laminate. Become. Therefore, the electrode plate body and the electrode lead can be joined with high strength, and for example, it is possible to ensure a high welding strength that is higher than the breaking strength of the electrode plate body.
- the electrode plate main body has active material layers on both surfaces of the current collector, the end surfaces of the active material layers on both surfaces and the electrode leads are melted. Part can be formed. Therefore, as shown in FIG. 1 and FIG. 2, not only the end surface of the active material layer 1 a sandwiched between the current collector 1 b and the electrode lead 2 but also the end surface of the other active material layer 1 a Can be covered. Accordingly, the entire laminate of the electrode plate main body and the electrode lead can be firmly bonded.
- the melting efficiency of the active material and the metal component of the electrode lead, and further the melting efficiency of the metal component of the current collector and the metal component of the electrode lead are increased. Can do. For this reason, a large amount of energy is not consumed for welding although a large melted portion can be formed to ensure high joint strength. That is, it is possible to ensure high bonding strength with low energy consumption. For example, when plasma welding is performed, the number of irradiation of energy rays required for welding can be reduced.
- the melting part includes an alloy of the constituent components of the electrode plate body other than the active material and the metal components of the electrode lead.
- a component of the electrode plate body when the active material layer includes a metal component as a conductive material, a metal component as the conductive material, a metal component of a current collector, and the like can be given.
- the alloy in the molten part can include at least an alloy of the active material and the metal component of the electrode lead, and the active material, the metal component of the conductive material and / or the current collector, and the metal component of the electrode lead. Alloys may be included.
- the thickness of the melted portion in the thickness direction of the laminate is equal to or greater than the total thickness of the laminate and the electrode lead, and is preferably larger than the total thickness of the laminate and the electrode lead.
- the thickness of the melted part is, for example, 180 ⁇ m or more, preferably 200 ⁇ m or more, and more preferably 250 ⁇ m or more.
- the electrode plate for an electrochemical element as the first electrode is opposed to the second electrode having the opposite polarity to the first electrode, and a separator is provided between the first and second electrodes. Use with the intervening.
- FIG. 3 and 4 are perspective views schematically showing the configuration of the electrode plate for an electrochemical element and the separator.
- FIG. 3 shows a mode in which the separator 4 is disposed on the surface of the electrode plate for an electrochemical element in FIG. 2 on the electrode lead 2 side.
- FIG. 4 shows an aspect in which the separator 4 is disposed on the surface of the electrode plate for an electrochemical element of FIG. 2 on the electrode lead 2 side and on the surface of the active material layer 1a on the side not in contact with the electrode lead 2. Indicates.
- the thickness of the melted part is the thickness of the electrode plate (first electrode) and the thickness of the separator disposed in contact with one surface or both surfaces of the electrode plate.
- the total thickness may be less than or equal to the total thickness.
- the thickness of the melted part is, for example, 500 ⁇ m or less, preferably 450 ⁇ m or less, more preferably 400 ⁇ m or less or 300 ⁇ m or less.
- an electrode group formed by winding or laminating an electrode plate (first electrode) with a second electrode facing a second electrode.
- first electrode first electrode
- second electrode second electrode facing a second electrode.
- FIG. 5 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element according to another embodiment of the present invention.
- the electrode lead 2 is disposed so that one end portion in the short direction and one end portion of the electrode plate body 1 are close to each other, and the melting portion 3 includes the end surface in the short direction of the electrode lead 2, It is formed by welding the active material layer 1 a of the plate body 1.
- the active material layer melts at least the end face, but is melted not only to the end face but also to a portion sandwiched between the current collector and the electrode lead. When the active material layer melts to such a portion, it becomes possible to secure a higher bonding strength.
- the melted portion formed at one end in the longitudinal direction or the short direction of the electrode lead not only has a large thickness in the thickness direction of the laminate, but also the longitudinal direction or the short side of the electrode lead. The length in the direction is also increased.
- the molten part contains an alloy containing the constituent elements of the active material, but does not contain the active material itself. Further, the melted part is formed at one end of the active material layer. Therefore, the length of the melted portion can be restated as the length of the region not including the active material from one end portion of the electrode lead.
- the length of the melted part (for example, the length in the longitudinal direction or the short direction of the electrode lead) is, for example, 250 ⁇ m or more or 300 ⁇ m or more, preferably 350 ⁇ m or more, and more preferably 400 ⁇ m or more.
- the upper limit of the length of the melted part is, for example, 700 ⁇ m or less, preferably 600 ⁇ m or less, and more preferably 550 ⁇ m. These lower limit value and upper limit value can be appropriately selected and combined.
- the length of the melted part may be, for example, 300 to 600 ⁇ m or 400 to 700 ⁇ m.
- the active material layer hardly melts.
- the length is shorter, for example, less than 150 ⁇ m.
- the active material layer hardly melts, so even if the X-ray diffraction spectrum of the melted part is measured, the peak derived from the alloy of the active material and the metal component of the electrode lead is Almost no detection.
- a peak derived from an alloy of the active material and the metal component of the electrode lead is detected in the X-ray diffraction spectrum at any position of the fusion zone.
- the difference between the melted portion formed by the conventional method and the melted portion in the present invention is the presence or absence of a peak derived from an alloy of the active material in the melted portion and the metal component of the electrode lead in the X-ray diffraction spectrum. It can also be confirmed by the difference.
- the active material and the metal component of the electrode lead when the X-ray diffraction spectrum is measured at a position 150 ⁇ m from the extreme end of the melted part in the longitudinal direction or the short direction of the electrode lead, the active material and the metal component of the electrode lead The peak derived from the alloy can be confirmed.
- the depth at which the X-ray diffraction spectrum is measured is not particularly limited, and may be measured at a position that is half the thickness of the melted portion in the thickness direction of the laminate. You may measure at (that is, shallow position).
- the endmost part is the endmost part on the side opposite to the electrode lead body of the melting part.
- the X-ray diffraction spectrum is measured at any position 150 ⁇ m from the shortest part of the melted part in the longitudinal direction or short-side direction of the electrode lead, and the alloy of the active material and the metal component of the electrode lead is obtained.
- the derived peak can be detected.
- FIG. 6 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element according to still another embodiment of the present invention.
- two melting portions 3 are formed at one end in the longitudinal direction of the electrode lead 2, and the electrode plate body 1 and the electrode lead 2 are joined by these melting portions 3.
- FIG. 6 it is the same as that of the structure of FIG. 2 except that the two fusion
- the number of melted parts is not limited to one or two, and may be three or more.
- the melted portion does not necessarily have to be formed in a spot shape as shown in FIGS. 1 to 6, and covers the whole or most of the end surface of the electrode lead in the width direction at one end of the electrode plate body. You may form in a wide shape (for example, strip
- the welding strength can be further increased by forming a plurality of melted portions at one end of the electrode plate body or by forming the melted portions into a wide shape such as a band shape.
- the electrode plate of the present invention is useful as an electrode plate for various electrochemical elements because of high bonding strength between the electrode lead and the electrode plate body.
- the electrochemical element includes the above-described electrode plate for an electrochemical element as a first electrode, a second electrode having a polarity opposite to the first electrode, and a separator interposed between the first electrode and the second electrode.
- the electrochemical element in which the electrode plate is used include a battery and a capacitor (for example, an electric double layer capacitor) having a current collecting structure similar to that of the secondary battery.
- the battery include primary batteries such as alkaline dry batteries and lithium primary batteries, alkaline secondary batteries such as nickel hydride storage batteries, and secondary batteries such as non-aqueous electrolyte secondary batteries (such as lithium ion secondary batteries).
- the electrode plate main body included in the electrode plate includes a laminate of a current collector containing metal and an active material layer formed on the surface and containing an active material.
- the electrode lead can be alloyed.
- the combination of the metal contained in the metal and the metal contained in the active material or current collector may be selected as appropriate.
- the type of metal contained in the electrode lead, the metal contained in the current collector, and the active material can be either the type of electrochemical element or the type of electrode on which the electrode plate is used (positive electrode (or anode) or negative electrode (or cathode)). )) And so on.
- Examples of the metal contained in the electrode lead include copper, copper alloy, nickel, nickel alloy, aluminum, aluminum alloy, silver, silver alloy, gold, and gold alloy. Of these, copper or a copper alloy is preferable.
- the metal contained in the current collector is selected according to the type of electrochemical element or the type of electrode, and examples thereof include copper, copper alloy, nickel, nickel alloy, aluminum, aluminum alloy, and stainless steel.
- Examples of the active material include metals that can be alloyed with the above-described metals contained in the current collector, alloys of these metals, metal compounds, and the like, and are selected according to the type of electrochemical element, the type of electrode, and the like.
- the electrode plate of the present invention is particularly useful for use in non-aqueous electrolyte secondary batteries such as lithium ion batteries among electrochemical elements.
- non-aqueous electrolyte secondary batteries such as lithium ion batteries among electrochemical elements.
- the constituent elements of the electrochemical device will be described below by taking a nonaqueous electrolyte secondary battery as an example.
- the nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator interposed therebetween, and a nonaqueous electrolyte.
- the electrode plate of the present invention is preferably used as a negative electrode.
- the negative electrode includes a current collector and an active material layer formed on the surface of the current collector.
- the active material layer may be formed on one surface of the current collector, or may be formed on both surfaces.
- Examples of the material of the negative electrode current collector include copper and copper alloys.
- the form of the negative electrode current collector is not particularly limited, and may be a nonporous metal foil or may be porous.
- the thickness of the negative electrode current collector can be selected from a range of 5 to 50 ⁇ m, for example.
- the negative electrode active material layer may be formed of a negative electrode active material, and may contain a binder, a conductive agent, a thickener, and the like in addition to the negative electrode active material.
- the negative electrode active material include various materials that can be alloyed with the metal component of the electrode lead and that can reversibly occlude and release lithium ions, such as silicon, silicon alloys, silicon compounds (silicon oxide SiOx, silicon nitride). Alloy, silicon carbide, etc.), tin, tin alloys, tin compounds (tin oxide SnOx, tin nitride, tin carbide, etc.), and alloy materials such as lithium alloys containing Al, Zn and / or Mg, etc. It can be illustrated. In silicon oxide and tin oxide, the coefficient x is 0 ⁇ x ⁇ 2.
- Examples of the silicon alloy include an alloy containing silicon and lithium, an alloy containing Al, Zn, and / or Mg in addition to silicon and lithium.
- Examples of the tin alloy include an alloy containing tin and lithium, an alloy containing Al, Zn, and / or Mg in addition to tin and lithium.
- These negative electrode active materials can be used individually by 1 type or in combination of 2 or more types.
- silicon, silicon alloys, silicon compounds, and the like are particularly preferable. Among these, an alloy containing at least silicon and lithium is preferable.
- a lithium foil or a lithium alloy foil may be attached to the surface of the negative electrode active material layer in the negative electrode active material layer. Lithium contained in the attached lithium foil or alloy foil is appropriately occluded in the negative electrode active material layer.
- the electrode lead electrically connected to the negative electrode preferably contains copper or a copper alloy.
- an electrode lead including copper or a copper alloy and an electrode plate main body including an alloy containing lithium and an element such as silicon or tin as an active material are welded to one end of the electrode plate main body.
- the active material contains lithium
- the melting temperature becomes lower than that of silicon or tin alone, and the melting easily proceeds. Therefore, when the melted part is formed so as to mainly melt the active material layer, the melted silicon or tin diffuses into the copper or copper alloy contained in the electrode lead.
- silicon or tin diffuses into copper or a copper alloy, the melting temperature becomes lower than the melting temperature of the original copper or copper alloy, so that the melting is further facilitated.
- the melting of the active material is facilitated and the melting efficiency of the metal component of the electrode lead is further increased.
- the melting amount of the active material and the electrode lead is increased, and the size of the melted portion is increased.
- the negative electrode current collector also contains copper and a copper alloy, as in the case of the electrode lead, like the alloying of the active material and the metal component of the electrode lead, the current collector copper and copper alloy, Alloying with the active material, and hence the electrode lead, is likely to proceed. Therefore, the amount of melting of the current collector is also increased, and the size of the melted portion is further increased.
- the melted portion thus formed contains an alloy of copper and silicon or tin.
- the molten part contains an alloy of copper and silicon.
- the composition of such an alloy is not particularly limited, but the alloy preferably contains Cu 5 Si.
- the negative electrode active material layer can be formed using a negative electrode slurry containing a negative electrode active material, a binder, and a dispersion medium.
- the negative electrode slurry may further contain a thickener, a conductive material, and the like as necessary.
- the negative electrode active material layer can be formed by preparing a negative electrode slurry containing these components and applying it to the surface of the negative electrode current collector.
- a negative electrode active material is deposited on the surface of the current collector by a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or a CVD method to form a thin film of the negative electrode active material.
- a negative electrode active material layer may be formed.
- fluorine resins such as polyvinylidene fluoride (PVDF); acrylic resins such as polymethyl acrylate and ethylene-methyl methacrylate copolymer; rubbers such as styrene-butadiene rubber, acrylic rubber, or modified products thereof
- PVDF polyvinylidene fluoride
- acrylic resins such as polymethyl acrylate and ethylene-methyl methacrylate copolymer
- rubbers such as styrene-butadiene rubber, acrylic rubber, or modified products thereof
- the material can be exemplified.
- the ratio of the binder is, for example, 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of the active material.
- Examples of the dispersion medium contained in the negative electrode slurry include water, alcohols such as ethanol, ethers such as tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), or a mixed solvent thereof.
- the negative electrode slurry can be prepared by a method using a conventional mixer such as a planetary mixer or a disperser.
- the negative electrode slurry can be applied to the surface of the negative electrode current collector by, for example, a conventional application method using various coaters.
- the coating film of the negative electrode slurry is usually dried and subjected to rolling.
- the conductive agent examples include carbon black; conductive fibers such as metal fibers and carbon fibers; and carbon fluoride.
- the ratio of the conductive agent is, for example, 0.1 to 7 parts by mass per 100 parts by mass of the active material.
- the thickener examples include cellulose derivatives such as carboxymethyl cellulose (CMC); poly C 2-4 alkylene glycol such as polyethylene glycol.
- the ratio of the thickener is, for example, 0.1 to 10 parts by mass per 100 parts by mass of the active material.
- the thickness of the negative electrode active material layer is, for example, 5 to 200 ⁇ m, preferably 5 to 100 ⁇ m.
- the thickness of the negative electrode active material layer formed by deposition is, for example, 5 to 50 ⁇ m or 5 to 30 ⁇ m.
- the positive electrode includes a current collector and an active material layer formed on the surface of the current collector.
- the active material layer may be formed on one surface of the current collector, or may be formed on both surfaces.
- Examples of the material of the positive electrode current collector include stainless steel, aluminum, aluminum alloy, and titanium.
- the form and thickness of the positive electrode current collector are the same as those of the negative electrode current collector.
- the positive electrode active material layer may contain a binder, a conductive agent, a thickener and the like in addition to the positive electrode active material.
- the positive electrode active material layer can be formed by a method similar to that of the negative electrode active material layer, using a positive electrode slurry containing these components. As each component contained in a positive electrode slurry, what was illustrated by the term of the negative electrode slurry can be used, and content of each component can be selected from the same range as the case of a negative electrode slurry.
- the thickness of the positive electrode active material layer can be selected from the same range as the thickness of the negative electrode active material layer.
- positive electrode active material known nonaqueous electrolyte secondary battery positive electrode active materials can be used, and among these, lithium transition metal oxides are preferably used.
- a positive electrode active material can be used individually by 1 type or in combination of 2 or more types.
- Li x M a 1-y M b y O 2 (0.9 ⁇ x ⁇ 1.1, 0 ⁇ y ⁇ 0.7, M a is Ni , Co, Mn, Fe, at least one selected from the group consisting of Ti or the like, M b other such as at least one metal element) other than M a is, LiMn 2 O 4, LiFePO 4 , LiCoPO 4, LiMnPO 4 and so on.
- lithium transition metal oxide for example, lithium cobaltate and a modified product thereof, lithium nickelate and a modified product thereof, lithium manganate and a modified product thereof are preferable.
- a lithium transition metal oxide of the above formula, Li x Ni 1-y M c y O 2 (0.9 ⁇ x ⁇ 1.1,0 ⁇ y ⁇ 0.7, M c is Li x Co 1 ⁇ , represented by lithium nickel oxide represented by at least one selected from the group consisting of Co, Mn, Fe, Ti, Al, Mg, Ca, Sr, Zn, Y, Yb, Nb, and As) y M 2 y O 2 (0.9 ⁇ x ⁇ 1.1, 0 ⁇ y ⁇ 0.7, M 2 is Ni, Mn, Fe, Ti, Al, Mg, Ca, Sr, Zn, Y, Yb , At least one selected from the group consisting of Nb and As).
- y is preferably 0.05 ⁇ y ⁇ 0.5.
- y is preferably 0 ⁇ y ⁇ 0.3.
- the lithium transition metal oxides of the above formula LiNi 1/2 Mn 1/2 O 2 , LiNiO 2 , LiNi 1/2 Fe 1/2 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 1/3 Mn 1/3 Co 1/3 O 2 , LiCoO 2 , LiMnO 2 and the like are preferable.
- a resin-made microporous film, a nonwoven fabric, a woven fabric, or the like, or an inorganic porous film based on a filler such as a metal oxide can be used.
- the separator may be a laminate of a plurality of porous layers. Each porous layer can be formed of a single-layer separator such as a microporous film, and a plurality of different types of porous layers may be combined.
- the resin constituting the microporous film and the nonwoven fabric separator include polyolefins such as polyethylene and polypropylene; polyamide; polyamideimide; polyimide; cellulose and the like.
- the inorganic porous film includes a filler and a resin binder that binds the filler. The thickness of the separator is, for example, 5 to 100 ⁇ m or 5 to 50 ⁇ m.
- a non-aqueous electrolyte having lithium ion conductivity is used as the non-aqueous electrolyte.
- the non-aqueous electrolyte includes a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.
- Non-aqueous solvents include cyclic carbonates such as propylene carbonate and ethylene carbonate (EC); chain carbonates such as diethyl carbonate, ethylmethyl carbonate (EMC) and dimethyl carbonate; cyclic esters such as ⁇ -butyrolactone and ⁇ -valerolactone Examples thereof include carboxylic acid esters.
- cyclic carbonates such as propylene carbonate and ethylene carbonate (EC); chain carbonates such as diethyl carbonate, ethylmethyl carbonate (EMC) and dimethyl carbonate
- cyclic esters such as ⁇ -butyrolactone and ⁇ -valerolactone Examples thereof include carboxylic acid esters.
- lithium salt examples include LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 , LiC (SO 2 CF 3 3 ).
- a lithium salt can be used individually by 1 type or in combination of 2 or more types.
- the concentration of the lithium salt in the nonaqueous electrolyte is, for example, 0.5 to 1.8 mol / L.
- a known additive such as a vinylene carbonate compound such as vinylene carbonate may be added to the non-aqueous electrolyte.
- the nonaqueous electrolyte secondary battery can be manufactured by a known method according to the shape of the battery.
- a positive electrode, a negative electrode, and a separator disposed between them are wound to form an electrode group, and the electrode group and the electrolyte can be accommodated in a battery case. .
- the electrode group is not limited to a wound one, but may be a laminated one or a folded one.
- the shape of the electrode group may be a cylindrical shape or a flat shape having an oval end surface perpendicular to the winding axis, depending on the shape of the battery or battery case.
- aluminum As the battery case material, aluminum, an aluminum alloy (such as an alloy containing a trace amount of a metal such as manganese or copper), a steel plate, or the like can be used.
- FIG. 9 is a longitudinal sectional view schematically showing a cylindrical nonaqueous electrolyte secondary battery according to an embodiment of the present invention.
- the cylindrical non-aqueous electrolyte secondary battery 10 includes a bottomed cylindrical battery case 16, an electrode group 14 accommodated in the battery case 16, and a non-aqueous electrolyte (not shown). Sealed with a sealing body 18.
- the electrode group 14 is formed by winding the positive electrode 11 and the negative electrode 12 in a vortex shape with a separator 13 interposed therebetween.
- the electrode group 14 is housed inside the battery case 16 with the upper insulating plate 15a disposed on the upper surface and the lower insulating plate 15b disposed on the bottom surface.
- the positive electrode lead 11 a led out from the upper part of the electrode group 14 is electrically connected to a sealing body 18 that seals the opening of the battery case 16.
- the negative electrode lead 12 a led out from the lower part of the electrode group 14 is electrically connected to the inner bottom surface of the battery case 16.
- the negative electrode lead 12a is a molten portion formed by welding the end surface of the negative electrode active material layer included in the negative electrode 12 and the end surface of the negative electrode lead 12a at one end portion of the negative electrode 12 of the electrode group 14. And are electrically connected.
- the nonaqueous electrolyte is injected into the battery case 16 after the electrode group 14 is stored in a predetermined amount. After injecting the nonaqueous electrolyte, a sealing body 18 having a sealing gasket 17 attached to the periphery is inserted into the opening of the battery case 16. And the nonaqueous electrolyte secondary battery 10 can be obtained by crimping and sealing so that the opening part of the battery case 16 may be bent inward.
- the method for producing an electrode plate for an electrochemical element used as an electrode for a nonaqueous electrolyte secondary battery includes the following steps (i) to (iii).
- the electrode plate body can be prepared by laminating an active material layer on the surface of the current collector to form a laminate.
- a laminated body can be formed according to the formation method of the negative electrode in said nonaqueous electrolyte secondary battery.
- step (ii) electrode leads are arranged on a part of the surface of the active material layer of the electrode plate body prepared in step (i). At this time, the electrode lead is placed on the surface of the active material layer so that one end of the electrode plate body and one end of the electrode lead containing metal are close to each other so that a melted part can be easily formed in the next step (iii). Deploy. In the next step (iii), at least the end surface of the active material layer and the end surface of the electrode lead in the electrode plate main body are welded. Therefore, in step (ii), at least the end surface of the active material layer and the end surface of the electrode lead are Make it close. At this time, the end faces of the current collector may be brought close together with these end faces.
- the electrode lead may be arranged so that one end in the longitudinal direction and one end of the electrode plate main body are close to each other. As shown in FIG. You may arrange
- step (iii) at least one end surface of the active material layer and an end surface of the electrode lead are welded to one end portion of the electrode plate body to form a melted portion.
- a molten part including at least an active material and a metal component of the electrode lead among the constituent components of the electrode plate body is formed. And let the thickness of the fusion
- the welding method is not particularly limited, and a known welding method for joining the electrode lead and the electrode plate body can be employed.
- arc welding such as TIG welding, plasma welding, and covering arc welding; electron beam welding; laser welding.
- arc welding particularly non-consumable electrode type arc welding such as TIG welding and plasma welding, particularly plasma welding is preferable.
- melting part is formed by welding is as above-mentioned.
- Example 1 A lithium ion secondary battery electrode plate having the structure shown in FIG. 1 was produced as follows. A laminated body was formed by forming a 20 ⁇ m thick active material layer 1a by vacuum-depositing silicon oxide on both surfaces of a 40 ⁇ m thick copper foil as the current collector 1b.
- lithium foil having a thickness of 10 ⁇ m was pasted on the surfaces of both active material layers 1a.
- the laminated body to which the lithium foil was attached was cut into a strip shape having a length of 300 mm and a width of 60 mm to produce an electrode plate body 1 having a thickness of 80 ⁇ m.
- an electrode lead 2 made of copper having a thickness of 100 ⁇ m, a length of 90 mm, and a width of 5 mm is disposed on the surface of one active material layer 1a of the electrode plate main body 1, on one end in the longitudinal direction of the electrode lead 2, and the electrode plate main body 1 was arranged so as to be close to one end.
- the end surface of the electrode plate body 1 and the end surface of the electrode lead 2 are welded by mainly melting the active material layer 1a of the electrode plate body 1 by plasma welding.
- One melting part 3 was formed in a spot shape. As shown in FIG. 1, the melting portion 3 is formed at one end portion of the electrode plate body 1 so as to cover the entire end surface of the laminate and the electrode lead in a state where the one end portion is melted.
- Example 2 As shown in FIG. 6, when plasma welding the end surface of the electrode plate body 1 and the end surface of the electrode lead 2 at one end portion of the electrode plate body 1, the two melted portions 3 are formed in a spot shape. In the same manner as in Example 1, the electrode plate body 1 and the electrode lead 2 were joined.
- the electrode lead 2 is mainly melted by plasma welding to weld the end face of the electrode plate main body 1 and the end face of the electrode lead 2 to melt.
- the electrode plate body 1 and the electrode lead 2 were joined in the same manner as in Example 1 except that the portion 3a was formed.
- Example 3 Fifteen electrode plates prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were prepared for each Example and Comparative Example, and the following evaluation was performed.
- the thickness of the melted portion in the thickness direction of the laminated body was all 200 ⁇ m or more.
- the thickness of the melted part was smaller than the thickness of the laminate.
- a high tensile strength of 0.5 N was obtained in all cases.
- an alloy of the constituent component of the electrode plate body and the metal component of the electrode lead is formed in the melting portion, and the thickness of the melting portion is equal to or greater than the total thickness of the laminate and the electrode lead. It has become. Therefore, it is considered that a tensile strength as high as 0.5 N was obtained in any of the examples.
- the fractured part by the tensile test was not the melted part but the current collector part. From this also, it is considered that the alloy contained in the melted part has a great influence on the tensile strength. It can be inferred that the tensile strength of the example depends on the tensile strength of the electrode plate body itself, and the tensile strength of the melted portion has higher welding strength than the tensile strength of the electrode plate body itself.
- Comparative Examples 1 and 2 in which the copper lead was mainly melted to form the melted portion, the peak derived from Cu 5 Si was not confirmed in the analysis result of the X-ray diffraction spectrum of the melted portion. Therefore, it can be seen that in Comparative Examples 1 and 2, alloying of copper contained in the electrode lead and silicon contained in the active material does not occur and the melting efficiency is low.
- Comparative Examples 1 and 2 the alloying of copper and silicon hardly proceeds, and the melted portion hardly contains an alloy of copper and silicon. Therefore, in these comparative examples, the tensile strength was low, and the sample was fractured with a load smaller than the value of 0.5 N in the example. In these comparative examples, it was confirmed that the current collector was not broken and was broken at the melted portion.
- Example 2 Regarding the state of the separator after winding, in Comparative Example 2, the separator was broken and deformed in the vicinity of the melted portion. Further, in Example 1, the separator was slightly broken and deformed in the vicinity of the melted portion, but in Example 2, no breakage and deformation of the separator were observed.
- the electrode plate for an electrochemical element of the present invention is suitable for use as an electrode in various batteries such as a non-aqueous electrolyte secondary battery and various electrochemical elements such as a capacitor.
- An electrochemical element including an electrode plate for an electrochemical element is suitable for large current discharge, for example, a driving power source for a power tool or an electric vehicle that requires high output, a large-capacity backup power source, a power storage This is useful for power supplies.
- the electrochemical element can be used for applications such as a driving power source in various portable electronic devices such as a mobile phone, a notebook personal computer, and a video camcorder, and a large power source in a household power storage device.
- Electrode plate main body 1a Active material layer 1b Current collector 2 Electrode lead 3, 3a, 3b Melting part 4, 13 Separator 10 Nonaqueous electrolyte secondary battery 11 Positive electrode 11a Positive electrode lead 12 Negative electrode 12b Negative electrode lead 14 Electrode group 15a Upper insulating plate 15b Lower insulating plate 16 Battery case 17 Sealing gasket 18 Sealing plate
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Abstract
Provided are an electrode plate for an electrochemical element, wherein an electrode plate main body and an electrode lead are highly strongly bonded to each other, a method for manufacturing such electrode plate, and an electrochemical element. This electrode plate for an electrochemical element includes: an electrode plate main body, which includes a laminated body of a strip-shaped current collector containing a metal, and active material layers, which are formed on the surfaces of the current collector, and contain an active material; a metal-containing electrode lead, which is disposed on a part of the surfaces of the active material layers; and a melting section, which electrically connects the electrode plate main body and the electrode lead to each other at one end portion of the electrode plate main body. The melting section contains an alloy composed of at least an active material and the metal component of the electrode lead.
Description
本発明は、電気化学素子用電極板およびその製造方法、ならびに電気化学素子に関し、特に、電極板と電極リードとの接合状態の改良に関する。
The present invention relates to an electrode plate for an electrochemical element, a method for manufacturing the same, and an electrochemical element, and more particularly, to an improved bonding state between an electrode plate and an electrode lead.
近年、携帯用電子機器の小型化、軽量化が進み、それらの電子機器の電源として、電気化学素子の中で、特に小型軽量で高出力な二次電池の需要が高まっている。中でも、リチウムイオン二次電池やニッケル水素蓄電池は、高いエネルギー密度を有し、耐振動性や耐衝撃性も高いことから、開発が盛んに進んでいる。
In recent years, portable electronic devices have become smaller and lighter, and as a power source for such electronic devices, demand for secondary batteries that are particularly small, light and high output among electrochemical elements is increasing. Among them, lithium ion secondary batteries and nickel metal hydride storage batteries have been actively developed because they have high energy density and high vibration resistance and impact resistance.
このような二次電池や、コンデンサなどの電気化学素子は、内部に極性の異なる一対の電極板を備えており、電極板は、封口板などの外部端子と、電極リードを介して、電気的に接続される。電極板は、通常、集電体としての金属箔の両面に活物質層が形成された構造を有している。このような構造の電極板には、電極リードとしての短冊状の金属片を接続するために、適当な間隔を隔てて、活物質層が形成されていない集電体露出部が設けられている。
Such electrochemical devices such as secondary batteries and capacitors have a pair of electrode plates with different polarities inside, and the electrode plates are electrically connected via external terminals such as sealing plates and electrode leads. Connected to. The electrode plate usually has a structure in which active material layers are formed on both surfaces of a metal foil as a current collector. The electrode plate having such a structure is provided with a current collector exposed portion on which an active material layer is not formed at an appropriate interval in order to connect strip-shaped metal pieces as electrode leads. .
このように、電極板と電極リードとの電気的な接続は、従来、集電体と電極リードとを接続することにより行われている。なぜなら、活物質層を介して、電極板と電極リードとを接続させようとすると、十分な電気的接続を確保し難いからである。集電体露出部(すなわち、活物質層の未塗工部分)は、例えば、活物質を含む電極スラリーを塗布せずに作製されるか、もしくは、電極スラリーを塗布した後に、形成された塗膜の一部を取り除くことにより作製される(特許文献1および特許文献2参照)。
Thus, the electrical connection between the electrode plate and the electrode lead is conventionally performed by connecting the current collector and the electrode lead. This is because if it is attempted to connect the electrode plate and the electrode lead through the active material layer, it is difficult to ensure sufficient electrical connection. The current collector exposed portion (that is, the uncoated portion of the active material layer) is prepared without applying the electrode slurry containing the active material, or formed after the electrode slurry is applied, for example. It is manufactured by removing a part of the film (see Patent Document 1 and Patent Document 2).
また、電極板の端面において、露出した集電体の端面と電極リードの端面とを、プラズマ溶接などにより、電気的に接続する方法も提案されている。(特許文献3参照)
Also, a method of electrically connecting the exposed end face of the current collector and the end face of the electrode lead at the end face of the electrode plate by plasma welding or the like has been proposed. (See Patent Document 3)
特許文献1や特許文献2のように、電極スラリーを用いて活物質層を形成する場合には、例えば、集電体表面に、電極スラリーを間欠的に塗布したり、電極スラリーを連続的に塗布した後、形成された塗膜の一部を除去したりすることにより、容易に、電極リードを接続するための活物質層の未塗工部分を形成することができる。しかし、未塗工部分の幅は、電極リードの幅よりも大きくする必要がある。そのため、未塗工部分の存在により活物質量が減少することとなり、高容量化を図る上での障害となっている。
When the active material layer is formed using the electrode slurry as in Patent Document 1 and Patent Document 2, for example, the electrode slurry is intermittently applied to the current collector surface, or the electrode slurry is continuously applied. After coating, by removing a part of the formed coating film, an uncoated portion of the active material layer for connecting the electrode leads can be easily formed. However, the width of the uncoated portion needs to be larger than the width of the electrode lead. Therefore, the amount of the active material is reduced due to the presence of the uncoated portion, which is an obstacle to increase the capacity.
近年、電極スラリーの塗布により活物質層を形成する方法以外に、ケイ素、ゲルマニウム、またはスズなどを含む活物質を、集電体表面に蒸着などにより堆積させることにより活物質層を形成する方法が注目されている。堆積により活物質層を形成する場合、電極スラリーを用いて活物質層を形成する場合とは異なり、バインダーを用いる必要がない。また、堆積による活物質層は、集電体表面に一体的に密に形成されるため、活物質層と集電体の導電性も高まり、活物質層に含ませる導電材を低減したり、排除したりできる。このため、電極の厚みを小さくしながら高容量化を図ることができる。
In recent years, in addition to the method of forming an active material layer by applying electrode slurry, there is a method of forming an active material layer by depositing an active material containing silicon, germanium, tin, or the like on the surface of a current collector by vapor deposition or the like. Attention has been paid. When the active material layer is formed by deposition, it is not necessary to use a binder, unlike when the active material layer is formed using the electrode slurry. In addition, since the active material layer formed by deposition is integrally and densely formed on the surface of the current collector, the conductivity of the active material layer and the current collector is increased, and the conductive material included in the active material layer can be reduced, Can be eliminated. For this reason, it is possible to increase the capacity while reducing the thickness of the electrode.
ところが、堆積により活物質層を形成する場合には、部分的に活物質層を形成しないようにすることは非常に煩雑であり、形成された活物質層を部分的に取り除いたりすることは実質的に不可能である。つまり、堆積膜の場合には、集電体表面に集電体露出部を形成することは困難である。
However, when an active material layer is formed by deposition, it is very complicated not to partially form the active material layer, and it is substantially impossible to partially remove the formed active material layer. Is impossible. That is, in the case of a deposited film, it is difficult to form the current collector exposed portion on the current collector surface.
特許文献3の方法では、主に電極リードに熱を加えて、集電体端面の集電体露出部と、電極リードの端面とを溶接する。よって、活物質層が堆積膜の場合にも、集電体と電極リードとを電気的に接続することができる。
しかしながら、特許文献3の方法では、集電体露出部と電極リードとの間に、溶接により形成される溶融部は、電極リードの金属成分と集電体の金属成分との合金を含むが、電極リードの金属成分と活物質との合金は含まない。また、溶融部の大きさも小さい。さらに、活物質は溶融されないため、集電体と電極リードとの間には活物質層が存在することになり、集電体と電極リードの接合面積が非常に小さくなる。その結果、溶接強度が小さくなり、溶接後に溶融部の破断が発生しやすくなるという不都合が発生する。 In the method ofPatent Document 3, heat is mainly applied to the electrode lead to weld the current collector exposed portion on the current collector end surface and the end surface of the electrode lead. Therefore, even when the active material layer is a deposited film, the current collector and the electrode lead can be electrically connected.
However, in the method ofPatent Document 3, the melted portion formed by welding between the current collector exposed portion and the electrode lead includes an alloy of the metal component of the electrode lead and the metal component of the current collector. The alloy of the metal component of an electrode lead and an active material is not included. Also, the size of the melted part is small. Furthermore, since the active material is not melted, an active material layer exists between the current collector and the electrode lead, and the bonding area between the current collector and the electrode lead becomes very small. As a result, the welding strength is reduced, and there is a problem that the fracture of the melted portion tends to occur after welding.
しかしながら、特許文献3の方法では、集電体露出部と電極リードとの間に、溶接により形成される溶融部は、電極リードの金属成分と集電体の金属成分との合金を含むが、電極リードの金属成分と活物質との合金は含まない。また、溶融部の大きさも小さい。さらに、活物質は溶融されないため、集電体と電極リードとの間には活物質層が存在することになり、集電体と電極リードの接合面積が非常に小さくなる。その結果、溶接強度が小さくなり、溶接後に溶融部の破断が発生しやすくなるという不都合が発生する。 In the method of
However, in the method of
本発明の目的は、電極板本体と電極リードとが高い強度で接合された電気化学素子用電極板およびその製造方法、ならびに電気化学素子を提供することである。
An object of the present invention is to provide an electrode plate for an electrochemical element in which an electrode plate body and an electrode lead are bonded with high strength, a method for manufacturing the same, and an electrochemical element.
本発明の一局面は、金属を含む帯状の集電体と、集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体、活物質層の一部の表面に配置された金属を含む電極リード、および電極板本体の一端部において、電極板本体と、電極リードとを、電気的に接続する溶融部を具備し、溶融部は、少なくとも活物質と、電極リードの金属成分との合金を含む、電気化学素子用電極板に関する。
One aspect of the present invention is an electrode plate body including a laminate of a strip-shaped current collector containing a metal and an active material layer formed on the surface of the current collector, and a part of the active material layer The electrode lead including the metal disposed on the surface of the electrode, and at one end of the electrode plate body, the electrode plate body and the electrode lead are provided with a melting portion that electrically connects, and the melting portion includes at least an active material The present invention also relates to an electrode plate for an electrochemical element including an alloy with a metal component of an electrode lead.
本発明の他の一局面は、金属を含む帯状の集電体と、集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体を準備する工程と、活物質層の一部の表面に、電極板本体の一端部と、金属を含む電極リードの一端部とが近接するように、電極リードを配置する工程と、電極板本体の一端部において、少なくとも活物質層の端面と、電極リードの端面とを溶接することにより、少なくとも活物質と、電極リードの金属成分との合金を含み、かつ電極板本体と、電極リードとを、電気的に接続する溶融部を形成する工程と、を具備する、電気化学素子用電極板の製造方法に関する。
Another aspect of the present invention is a step of preparing an electrode plate body including a laminate of a band-shaped current collector containing a metal and an active material layer formed on the surface of the current collector and containing an active material; In the step of arranging the electrode lead so that one end of the electrode plate main body and one end of the electrode lead containing metal are close to a part of the surface of the active material layer, and one end of the electrode plate main body, At least the end surface of the active material layer and the end surface of the electrode lead are welded to at least contain an alloy of at least the active material and the metal component of the electrode lead, and the electrode plate body and the electrode lead are electrically connected. And a step of forming a melted portion. The method of manufacturing an electrode plate for an electrochemical element.
本発明のさらに他の一局面は、第1電極としての、上記の電気化学素子用電極板と、第1電極とは反対の極性の第2電極と、第1電極と第2電極との間に介在するセパレータとを含む、電気化学素子に関する。
Still another aspect of the present invention is the above-described electrode plate for an electrochemical element as a first electrode, a second electrode having a polarity opposite to the first electrode, and between the first electrode and the second electrode. The present invention relates to an electrochemical element including a separator interposed between the two.
本発明では、集電体と活物質層との積層体を含む電極板本体の一端部において、電極板本体と電極リードとを溶融部により電気的に接続する際に、溶融部が、少なくとも活物質と、電極リードの金属成分との合金を含む。これにより、電極板本体の一端部において、電極リードと接続するにも拘わらず、電極板本体と電極リードとを高い強度で接合できる。
In the present invention, when the electrode plate main body and the electrode lead are electrically connected to each other at the one end portion of the electrode plate main body including the laminate of the current collector and the active material layer, the molten portion is at least active. It includes an alloy of the material and the metal component of the electrode lead. As a result, the electrode plate body and the electrode lead can be joined with high strength at one end of the electrode plate body, despite being connected to the electrode lead.
本発明の新規な特徴を添付の請求の範囲に記述するが、本発明は、構成および内容の両方に関し、本発明の他の目的および特徴と併せ、図面を照合した以下の詳細な説明によりさらによく理解されるであろう。
While the novel features of the invention are set forth in the appended claims, the invention will be further described by reference to the following detailed description, taken in conjunction with the other objects and features of the invention, both in terms of construction and content. It will be well understood.
以下、必要に応じて、図面を参照しながら、本発明の実施形態について説明する。
(電気化学素子用電極板および電気化学素子)
本発明の電気化学素子用電極板は、金属を含む帯状の集電体と、集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体、活物質層の一部の表面に配置された金属を含む電極リード、および電極板本体の一端部において、電極板本体と、電極リードとを、電気的に接続する溶融部を具備する。溶融部は、少なくとも活物質と、電極リードの金属成分との合金を含む。 Hereinafter, embodiments of the present invention will be described with reference to the drawings as necessary.
(Electrode plate for electrochemical element and electrochemical element)
An electrode plate for an electrochemical device according to the present invention includes an electrode plate body including a laminate of a strip-shaped current collector containing metal and an active material layer formed on the surface of the current collector and containing an active material, and an active material An electrode lead including a metal disposed on a part of the surface of the layer, and a melting portion that electrically connects the electrode plate main body and the electrode lead at one end of the electrode plate main body. The melting part includes at least an alloy of the active material and the metal component of the electrode lead.
(電気化学素子用電極板および電気化学素子)
本発明の電気化学素子用電極板は、金属を含む帯状の集電体と、集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体、活物質層の一部の表面に配置された金属を含む電極リード、および電極板本体の一端部において、電極板本体と、電極リードとを、電気的に接続する溶融部を具備する。溶融部は、少なくとも活物質と、電極リードの金属成分との合金を含む。 Hereinafter, embodiments of the present invention will be described with reference to the drawings as necessary.
(Electrode plate for electrochemical element and electrochemical element)
An electrode plate for an electrochemical device according to the present invention includes an electrode plate body including a laminate of a strip-shaped current collector containing metal and an active material layer formed on the surface of the current collector and containing an active material, and an active material An electrode lead including a metal disposed on a part of the surface of the layer, and a melting portion that electrically connects the electrode plate main body and the electrode lead at one end of the electrode plate main body. The melting part includes at least an alloy of the active material and the metal component of the electrode lead.
図1は、本発明の一実施形態に係る電気化学素子用電極板の構成を示す概略断面図である。図2は、図1の電気化学素子用電極板の構成を概略的に示す斜視図である。電極板本体1は、金属箔などの、金属を含む帯状の集電体1bと、集電体1bの両方の表面に形成された活物質層1aとの積層体を含む。集電体1bのいずれの表面にも、全体に亘って活物質層1aが形成されている。ただし、集電体1bの端面には、活物質層1aは形成されておらず、集電体1bが露出している。電極板本体1の一方の活物質層1aの一部の表面には、金属箔などの金属を含む電極リード2が、電極板本体1の一端部と、電極リード2の一端部とが近接するように配置されている。
FIG. 1 is a schematic cross-sectional view showing a configuration of an electrode plate for an electrochemical element according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing a configuration of the electrode plate for an electrochemical element in FIG. The electrode plate body 1 includes a laminate of a strip-shaped current collector 1b containing metal, such as a metal foil, and an active material layer 1a formed on both surfaces of the current collector 1b. The active material layer 1a is formed over the entire surface of the current collector 1b. However, the active material layer 1a is not formed on the end face of the current collector 1b, and the current collector 1b is exposed. An electrode lead 2 containing a metal such as a metal foil is adjacent to one end of the electrode plate main body 1 and one end of the electrode lead 2 on a part of the surface of one active material layer 1 a of the electrode plate main body 1. Are arranged as follows.
図1では、電極板本体1の上記一端部には、電極板本体1の構成成分のうち、少なくとも活物質と、電極リード2の金属成分との合金を含む溶融部3が形成されている。溶融部3は、電極板本体1と、電極リード2とを、電極板本体1の一端部において、物理的に接続するとともに、電気的に接合する。溶融部3は、電極リード2の長手方向の一端部に形成されている。電気化学素子において、電極リード2は、外部端子などに接続される。また、図1では、積層体の厚さ方向における溶融部3の厚さは、積層体および電極リード2の合計厚さ以上となっている。
In FIG. 1, at one end of the electrode plate main body 1, a melting portion 3 including an alloy of at least an active material and a metal component of the electrode lead 2 among the constituent components of the electrode plate main body 1 is formed. The melting part 3 physically connects and electrically joins the electrode plate body 1 and the electrode lead 2 at one end of the electrode plate body 1. The melting part 3 is formed at one end of the electrode lead 2 in the longitudinal direction. In the electrochemical element, the electrode lead 2 is connected to an external terminal or the like. Further, in FIG. 1, the thickness of the melted portion 3 in the thickness direction of the laminated body is equal to or greater than the total thickness of the laminated body and the electrode lead 2.
一方、特許文献3のような従来の方法では、電極リードに熱が集中するため、集電体の端面と電極リードの端面とを溶接させて溶融部を形成しても、溶融部は、わずかに溶融する集電体と、電極リードとの溶融により形成されるだけである。そのため、溶融部は、集電体の金属成分と電極リードの金属成分との合金を含むが、活物質と電極リードの金属成分との合金は含まない。このような従来の方法により形成される電気化学素子用電極板の概略断面図を図7および図8に示す。
On the other hand, in the conventional method such as Patent Document 3, since heat concentrates on the electrode lead, even if the end surface of the current collector and the end surface of the electrode lead are welded to form the melted portion, the melted portion is slightly It is only formed by melting the current collector that melts into the electrode lead and the electrode lead. For this reason, the molten part includes an alloy of the metal component of the current collector and the metal component of the electrode lead, but does not include an alloy of the active material and the metal component of the electrode lead. A schematic cross-sectional view of an electrode plate for an electrochemical element formed by such a conventional method is shown in FIGS.
図7において、電極板本体1は、金属を含む帯状の集電体1bと、集電体1bの両方の表面に形成された活物質層1aとの積層体を含む。電極板本体1の一方の活物質層1aの一部の表面には、金属を含む電極リード2が、電極板本体1の一端部と、電極リード2の一端部とが近接するように配置されている。そして、電極板本体1の上記一端部には、集電体1bの端面と、電極リード2の端面とを溶接することにより形成された溶融部3aが形成されている。なお、溶融部3aは、図1の場合と同様に、電極リード2の長手方向の一端部に形成される。
In FIG. 7, the electrode plate body 1 includes a laminate of a strip-shaped current collector 1b containing metal and an active material layer 1a formed on both surfaces of the current collector 1b. An electrode lead 2 containing a metal is disposed on a part of the surface of one active material layer 1a of the electrode plate body 1 so that one end portion of the electrode plate body 1 and one end portion of the electrode lead 2 are close to each other. ing. The one end portion of the electrode plate main body 1 is formed with a melting portion 3a formed by welding the end surface of the current collector 1b and the end surface of the electrode lead 2. In addition, the fusion | melting part 3a is formed in the one end part of the longitudinal direction of the electrode lead 2 similarly to the case of FIG.
このように、溶融部3aは、集電体1bの端面と電極リード2の端面との溶融により形成されるに過ぎないので、活物質と、電極リードの金属成分との合金を含まない。また、集電体1bおよび電極リード2の構成成分の溶融量が少ないので、溶融部3aのサイズは小さくなる。そのため、積層体の厚さ方向における溶融部3aの厚さは、積層体および電極リード2の合計厚さ以上にはならない。このような方法では、図7に示されるように、溶融部3aは、集電体1bの端面と電極リード2の端面とを橋架けするように、集電体1bと電極リード2とで挟まれた活物質層1aの端面に接着した状態で形成されるだけである。また、図7のように、電極板本体1が、集電体1bの両方の表面に活物質層1aを有する場合には、集電体と電極リードとで挟まれた活物質層の端面は溶融部で覆われるが、他方の活物質層1aの端面を溶融部で覆うことは困難である。そのため、従来の方法では、電極板本体と電極リードとの接合強度を高めることが難しい。
Thus, since the melting part 3a is merely formed by melting the end face of the current collector 1b and the end face of the electrode lead 2, it does not contain an alloy of the active material and the metal component of the electrode lead. Further, since the melting amount of the constituent components of the current collector 1b and the electrode lead 2 is small, the size of the melting portion 3a is reduced. Therefore, the thickness of the melted part 3 a in the thickness direction of the laminated body does not exceed the total thickness of the laminated body and the electrode lead 2. In such a method, as shown in FIG. 7, the melting part 3 a is sandwiched between the current collector 1 b and the electrode lead 2 so as to bridge the end surface of the current collector 1 b and the end surface of the electrode lead 2. It is only formed in a state where it is adhered to the end face of the active material layer 1a. As shown in FIG. 7, when the electrode plate body 1 has the active material layer 1a on both surfaces of the current collector 1b, the end surface of the active material layer sandwiched between the current collector and the electrode lead is Although it is covered with the melting part, it is difficult to cover the end face of the other active material layer 1a with the melting part. For this reason, it is difficult to increase the bonding strength between the electrode plate body and the electrode lead by the conventional method.
また、従来の方法でも、電極リードの溶融量が多くなるように溶接を行うと、溶融部の厚みを大きくすることは可能である。このような例を、図8に示す。図8は、従来の電気化学素子用電極板を示す概略断面図である。
Further, even in the conventional method, if the welding is performed so that the melting amount of the electrode lead is increased, the thickness of the molten portion can be increased. Such an example is shown in FIG. FIG. 8 is a schematic cross-sectional view showing a conventional electrode plate for an electrochemical element.
図8では、電極板本体1は、図7と同様に、集電体1bと、集電体1bの両方の表面に形成された活物質層1aとの積層体を含む。電極板本体1の一端部には、集電体1bの端面と、電極リード2の端面とを溶接することにより形成された溶融部3bが形成されている。図8では、電極リード2の溶融量が多くなるように、主に電極リード2を溶融させることにより、積層体の厚さ方向における溶融部3bの厚みが、積層体の厚みよりも大きくなっている。
In FIG. 8, the electrode plate body 1 includes a laminate of a current collector 1b and an active material layer 1a formed on both surfaces of the current collector 1b, as in FIG. At one end of the electrode plate main body 1, a melted part 3 b formed by welding the end face of the current collector 1 b and the end face of the electrode lead 2 is formed. In FIG. 8, the thickness of the melted part 3b in the thickness direction of the laminated body becomes larger than the thickness of the laminated body by mainly melting the electrode lead 2 so that the amount of melting of the electrode lead 2 is increased. Yes.
しかし、図8に示すような従来の方法でも、電極リード2を主に溶融させるため、溶融温度の高い活物質は溶融しにくく、合金化しない。そのため、溶融部3bの厚みを大きくして、電極板本体の一端部において、積層体の端面全体を覆うことができても、電極リード2は、積層体の端面だけ(特に活物質層とは、活物質層の端面だけ)に接した状態で形成された溶融部3bを介して、電極板本体1と接合した状態となるため、接合強度を大きくすることは困難である。
However, even in the conventional method as shown in FIG. 8, since the electrode lead 2 is mainly melted, the active material having a high melting temperature is difficult to melt and is not alloyed. Therefore, even if the thickness of the melted part 3b is increased so that the entire end face of the laminate can be covered at one end of the electrode plate body, the electrode lead 2 is formed only on the end face of the laminate (especially the active material layer) In addition, it is difficult to increase the bonding strength because it is in a state of being joined to the electrode plate body 1 via the melted portion 3b formed in a state of being in contact with only the end surface of the active material layer.
それに対し、本発明では、溶融部は、電極板本体の一端部において、少なくとも活物質層の端面と、電極リードの端面とを溶接することにより形成される。主に活物質層の端面を溶融させると、活物質層に含まれる活物質の溶融が進行しやすくなるとともに、活物質に含まれる元素を電極リードに含有させたり、集電体に含有させたりすることができる。これにより、電極リードや集電体の溶融を促進させることができるので、活物質と電極リードの金属成分との溶融効率、および集電体と電極リードの金属成分との溶融効率を高めることができる。
On the other hand, in the present invention, the melting part is formed by welding at least one end face of the active material layer and one end face of the electrode lead at one end of the electrode plate body. When the end surface of the active material layer is mainly melted, the active material contained in the active material layer is easily melted, and the elements contained in the active material are contained in the electrode lead or the current collector. can do. As a result, melting of the electrode lead and the current collector can be promoted, so that the melting efficiency between the active material and the metal component of the electrode lead and the melting efficiency of the current collector and the metal component of the electrode lead can be increased. it can.
そのため、活物質および集電体の金属成分、および電極リードの金属成分の溶融量が増加することにより、図1や図2に示されるように、溶融部のサイズが大きくなる。これにより、溶融部の厚さが大きくなり、積層体および電極リードの合計厚さ以上となる。つまり、活物質と電極リードの構成成分とが合金化して溶融部が形成されるとともに、電極板本体の一端部において、積層体の厚み方向に積層体の端面全体が溶融部で覆われることになる。そのため、電極板本体と電極リードとを高い強度で接合することができ、例えば、電極板本体の破断強度以上の高い溶接強度を確保することが可能となる。
Therefore, as the amount of melting of the metal component of the active material and the current collector and the metal component of the electrode lead increases, the size of the melted portion increases as shown in FIG. 1 and FIG. As a result, the thickness of the melted portion is increased to be equal to or greater than the total thickness of the laminate and the electrode lead. That is, the active material and the constituent components of the electrode lead are alloyed to form a melted portion, and at one end of the electrode plate body, the entire end surface of the laminate is covered with the melted portion in the thickness direction of the laminate. Become. Therefore, the electrode plate body and the electrode lead can be joined with high strength, and for example, it is possible to ensure a high welding strength that is higher than the breaking strength of the electrode plate body.
また、本発明では、電極板本体が、集電体の両方の表面に活物質層を有する場合にも、両方の表面の活物質層の端面と、電極リードとが溶融されることにより、溶融部を形成できる。そのため、図1や図2に示されるように、集電体1bと電極リード2とで挟まれた活物質層1aの端面だけでなく、他方の活物質層1aの端面も、溶融部3で覆うことができる。従って、電極板本体の積層体全体と電極リードとを強固に接合させることができる。
Further, in the present invention, even when the electrode plate main body has active material layers on both surfaces of the current collector, the end surfaces of the active material layers on both surfaces and the electrode leads are melted. Part can be formed. Therefore, as shown in FIG. 1 and FIG. 2, not only the end surface of the active material layer 1 a sandwiched between the current collector 1 b and the electrode lead 2 but also the end surface of the other active material layer 1 a Can be covered. Accordingly, the entire laminate of the electrode plate main body and the electrode lead can be firmly bonded.
本発明では、活物質層の端面を溶融させることにより、活物質と電極リードの金属成分との溶融効率、さらには集電体の金属成分と電極リードの金属成分との溶融効率も、高めることができる。そのため、溶融部を大きく形成して、高い接合強度を確保できるにも拘わらず、溶接に、それほど大きなエネルギーを消費しない。つまり、低エネルギー消費量で、高い接合強度を確保することが可能となる。例えば、プラズマ溶接する場合には、溶接に要するエネルギー線の照射数を減らすこともできる。
In the present invention, by melting the end surface of the active material layer, the melting efficiency of the active material and the metal component of the electrode lead, and further the melting efficiency of the metal component of the current collector and the metal component of the electrode lead are increased. Can do. For this reason, a large amount of energy is not consumed for welding although a large melted portion can be formed to ensure high joint strength. That is, it is possible to ensure high bonding strength with low energy consumption. For example, when plasma welding is performed, the number of irradiation of energy rays required for welding can be reduced.
溶融部は、活物質以外の電極板本体の構成成分と電極リードの金属成分との合金を含む。電極板本体の構成成分としては、活物質層が、導電材として金属成分を含む場合には、この導電材としての金属成分、集電体の金属成分などが挙げられる。つまり、溶融部の合金は、少なくとも活物質と電極リードの金属成分との合金を含むことができ、活物質と、導電材および/または集電体の金属成分と、電極リードの金属成分との合金を含んでもよい。
The melting part includes an alloy of the constituent components of the electrode plate body other than the active material and the metal components of the electrode lead. As a component of the electrode plate body, when the active material layer includes a metal component as a conductive material, a metal component as the conductive material, a metal component of a current collector, and the like can be given. In other words, the alloy in the molten part can include at least an alloy of the active material and the metal component of the electrode lead, and the active material, the metal component of the conductive material and / or the current collector, and the metal component of the electrode lead. Alloys may be included.
積層体の厚さ方向における溶融部の厚さは、積層体および電極リードの合計厚さ以上であり、好ましくは、積層体および電極リードの合計厚さよりも大きい。溶融部の厚さは、例えば、180μm以上、好ましくは200μm以上、さらに好ましくは250μm以上である。
なお、電気化学素子では、第1電極としての上記の電気化学素子用電極板と、第1電極とは反対の極性の第2電極とを対向させ、かつ第1および第2電極の間にセパレータを介在させた状態で使用する。 The thickness of the melted portion in the thickness direction of the laminate is equal to or greater than the total thickness of the laminate and the electrode lead, and is preferably larger than the total thickness of the laminate and the electrode lead. The thickness of the melted part is, for example, 180 μm or more, preferably 200 μm or more, and more preferably 250 μm or more.
In the electrochemical element, the electrode plate for an electrochemical element as the first electrode is opposed to the second electrode having the opposite polarity to the first electrode, and a separator is provided between the first and second electrodes. Use with the intervening.
なお、電気化学素子では、第1電極としての上記の電気化学素子用電極板と、第1電極とは反対の極性の第2電極とを対向させ、かつ第1および第2電極の間にセパレータを介在させた状態で使用する。 The thickness of the melted portion in the thickness direction of the laminate is equal to or greater than the total thickness of the laminate and the electrode lead, and is preferably larger than the total thickness of the laminate and the electrode lead. The thickness of the melted part is, for example, 180 μm or more, preferably 200 μm or more, and more preferably 250 μm or more.
In the electrochemical element, the electrode plate for an electrochemical element as the first electrode is opposed to the second electrode having the opposite polarity to the first electrode, and a separator is provided between the first and second electrodes. Use with the intervening.
図3および図4は、電気化学素子用電極板とセパレータとの構成を概略的に示す斜視図である。図3は、図2の電気化学素子用電極板の電極リード2側の表面に、セパレータ4が配置された態様を示す。また、図4は、図2の電気化学素子用電極板の電極リード2側の表面と、電極リード2と接触していない側の活物質層1aの表面とに、セパレータ4が配置された態様を示す。
3 and 4 are perspective views schematically showing the configuration of the electrode plate for an electrochemical element and the separator. FIG. 3 shows a mode in which the separator 4 is disposed on the surface of the electrode plate for an electrochemical element in FIG. 2 on the electrode lead 2 side. FIG. 4 shows an aspect in which the separator 4 is disposed on the surface of the electrode plate for an electrochemical element of FIG. 2 on the electrode lead 2 side and on the surface of the active material layer 1a on the side not in contact with the electrode lead 2. Indicates.
溶融部の厚さは、図3や図4に示されるように、電極板(第1電極)の厚さと、電極板の一方の表面または双方の表面に接触して配置されたセパレータの厚さとの合計厚さ以下であってもよく、この合計厚さより小さくてもよい。溶融部の厚さは、例えば、500μm以下、好ましくは450μm以下、さらに好ましくは400μm以下または300μm以下である。
As shown in FIG. 3 and FIG. 4, the thickness of the melted part is the thickness of the electrode plate (first electrode) and the thickness of the separator disposed in contact with one surface or both surfaces of the electrode plate. The total thickness may be less than or equal to the total thickness. The thickness of the melted part is, for example, 500 μm or less, preferably 450 μm or less, more preferably 400 μm or less or 300 μm or less.
電気化学素子では、電極板(第1電極)を、セパレータを介して、第2電極と対向させ、さらに、捲回または積層することにより形成した電極群を用いる場合がある。このような場合に、溶融部の厚さを、電極板とセパレータとの合計厚さ以下にすると、セパレータが破断したり、変形したりするのをより有効に抑制できる。これにより、電気化学素子における内部短絡を抑制できる。なお、この場合、溶融部は、電極板の一端部に接合しているが、セパレータの端面とは接合していない。
In an electrochemical element, there may be used an electrode group formed by winding or laminating an electrode plate (first electrode) with a second electrode facing a second electrode. In such a case, when the thickness of the melted portion is set to be equal to or less than the total thickness of the electrode plate and the separator, it is possible to more effectively suppress the separator from being broken or deformed. Thereby, the internal short circuit in an electrochemical element can be suppressed. In this case, the melted part is joined to one end of the electrode plate, but not joined to the end face of the separator.
図1~図4の態様では、電極リードの長手方向の一端部において、溶融部を形成した例を示したが、このような例に限らず、電極リードの短手方向の一端部に、溶融部を形成してもよい。図5は、本発明の他の一実施形態に係る電気化学素子用電極板の構成を概略的に示す斜視図である。図5では、電極リード2は、短手方向の一端部と、電極板本体1の一端部とが近接するように配置され、溶融部3は、電極リード2の短手方向の端面と、電極板本体1の活物質層1aとを溶接することにより形成されている。
1 to 4 show an example in which a melted part is formed at one end in the longitudinal direction of the electrode lead. However, the present invention is not limited to such an example, and a melted part is formed at one end in the short direction of the electrode lead. A part may be formed. FIG. 5 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element according to another embodiment of the present invention. In FIG. 5, the electrode lead 2 is disposed so that one end portion in the short direction and one end portion of the electrode plate body 1 are close to each other, and the melting portion 3 includes the end surface in the short direction of the electrode lead 2, It is formed by welding the active material layer 1 a of the plate body 1.
活物質層は、少なくとも端面を溶融させるが、端面だけでなく、集電体と、電極リードとの間に挟まれている部分まで溶融される。このような部分まで活物質層が溶融すると、さらに、高い接合強度を確保することが可能となる。
The active material layer melts at least the end face, but is melted not only to the end face but also to a portion sandwiched between the current collector and the electrode lead. When the active material layer melts to such a portion, it becomes possible to secure a higher bonding strength.
つまり、本発明では、電極リードの長手方向または短手方向の一端部に形成された溶融部は、積層体の厚さ方向における厚さが大きくなるだけでなく、電極リードの長手方向または短手方向における長さも大きくなる。
That is, in the present invention, the melted portion formed at one end in the longitudinal direction or the short direction of the electrode lead not only has a large thickness in the thickness direction of the laminate, but also the longitudinal direction or the short side of the electrode lead. The length in the direction is also increased.
溶融部は活物質の構成元素を含む合金を含むが、活物質自体は含まない。また、溶融部は、活物質層の一端部に形成される。そのため、溶融部の長さは、電極リードの一端部からの、活物質を含まない領域の長さと言い換えることができる。
The molten part contains an alloy containing the constituent elements of the active material, but does not contain the active material itself. Further, the melted part is formed at one end of the active material layer. Therefore, the length of the melted portion can be restated as the length of the region not including the active material from one end portion of the electrode lead.
溶融部の長さ(例えば、電極リードの長手方向または短手方向における長さ)は、例えば、250μm以上または300μm以上、好ましくは350μm以上、さらに好ましくは400μm以上である。溶融部の長さの上限は、例えば、700μm以下、好ましくは600μm以下、さらに好ましくは550μmである。これらの下限値と上限値とは適宜選択して組み合わせることができる。溶融部の長さは、例えば、300~600μmまたは400~700μmであってもよい。
The length of the melted part (for example, the length in the longitudinal direction or the short direction of the electrode lead) is, for example, 250 μm or more or 300 μm or more, preferably 350 μm or more, and more preferably 400 μm or more. The upper limit of the length of the melted part is, for example, 700 μm or less, preferably 600 μm or less, and more preferably 550 μm. These lower limit value and upper limit value can be appropriately selected and combined. The length of the melted part may be, for example, 300 to 600 μm or 400 to 700 μm.
これに対し、従来の方法により、集電体の端面と電極リードの端面とを溶接させることにより溶融部を形成した場合、活物質層はほとんど溶融しないため、溶融部の長さは、図7に示されるように短くなり、例えば、150μm未満である。
On the other hand, when the molten part is formed by welding the end face of the current collector and the end face of the electrode lead by a conventional method, the active material layer hardly melts. As shown in FIG. 5, the length is shorter, for example, less than 150 μm.
従来の方法で溶融部を形成した場合、活物質層はほとんど溶融しないため、溶融部のX線回折スペクトルを測定しても、活物質と電極リードの金属成分との合金に由来するピークは、ほとんど検出されない。これに対し、本願発明では、溶融部のいずれの位置においても、X線回折スペクトルにおいて、活物質と電極リードの金属成分との合金に由来するピークが検出される。
When the melted part is formed by a conventional method, the active material layer hardly melts, so even if the X-ray diffraction spectrum of the melted part is measured, the peak derived from the alloy of the active material and the metal component of the electrode lead is Almost no detection. On the other hand, in the present invention, a peak derived from an alloy of the active material and the metal component of the electrode lead is detected in the X-ray diffraction spectrum at any position of the fusion zone.
そのため、従来の方法により形成した溶融部と、本発明における溶融部との違いは、X線回折スペクトルにおける、溶融部における活物質と電極リードの金属成分との合金に由来するピークの有無や大きさの違いによって確認することもできる。
Therefore, the difference between the melted portion formed by the conventional method and the melted portion in the present invention is the presence or absence of a peak derived from an alloy of the active material in the melted portion and the metal component of the electrode lead in the X-ray diffraction spectrum. It can also be confirmed by the difference.
例えば、本発明の電極板では、電極リードの長手方向または短手方向において、溶融部の最端部から150μmの位置で、X線回折スペクトルを測定したときに、活物質と電極リードの金属成分との合金に由来するピークを確認することができる。X線回折スペクトルを測定する位置の深さは、特に制限されず、積層体の厚さ方向における溶融部の厚さの半分の位置で測定してもよく、厚さ方向において、より電極リード側(つまり、浅い位置)で測定してもよい。ここで、最端部とは、溶融部の電極リード本体とは反対側の最端部である。
For example, in the electrode plate of the present invention, when the X-ray diffraction spectrum is measured at a position 150 μm from the extreme end of the melted part in the longitudinal direction or the short direction of the electrode lead, the active material and the metal component of the electrode lead The peak derived from the alloy can be confirmed. The depth at which the X-ray diffraction spectrum is measured is not particularly limited, and may be measured at a position that is half the thickness of the melted portion in the thickness direction of the laminate. You may measure at (that is, shallow position). Here, the endmost part is the endmost part on the side opposite to the electrode lead body of the melting part.
好ましい態様では、電極リードの長手方向または短手方向において、溶融部の最短部から150μmのいずれの位置で、X線回折スペクトルを測定しても、活物質と電極リードの金属成分との合金に由来するピークを検出できる。
In a preferred embodiment, the X-ray diffraction spectrum is measured at any position 150 μm from the shortest part of the melted part in the longitudinal direction or short-side direction of the electrode lead, and the alloy of the active material and the metal component of the electrode lead is obtained. The derived peak can be detected.
図1~図5の態様では、電極板本体の一端部の一箇所に、溶融部を形成する例を示したが、このような例に限らず、電極板本体の一端部において、少なくとも1つの溶融部を形成すればよく、2つ以上の溶融部を形成してもよい。図6は、本発明のさらに他の一実施形態に係る電気化学素子用電極板の構成を概略的に示す斜視図である。図6では、電極リード2の長手方向の一端部において、2つの溶融部3が形成されており、これらの溶融部3により、電極板本体1と、電極リード2とが、接合している。図6では、2つの溶融部3が形成されている以外は、図2の構成と同じである。溶融部の個数は、例えば、1つまたは2つに限らず、3つ以上であってもよい。
In the embodiment of FIGS. 1 to 5, an example is shown in which a melted part is formed at one location of one end of the electrode plate body. However, the present invention is not limited to such an example, and at least one What is necessary is just to form a fusion | melting part and you may form two or more fusion | melting parts. FIG. 6 is a perspective view schematically showing a configuration of an electrode plate for an electrochemical element according to still another embodiment of the present invention. In FIG. 6, two melting portions 3 are formed at one end in the longitudinal direction of the electrode lead 2, and the electrode plate body 1 and the electrode lead 2 are joined by these melting portions 3. In FIG. 6, it is the same as that of the structure of FIG. 2 except that the two fusion | melting parts 3 are formed. The number of melted parts is not limited to one or two, and may be three or more.
また、溶融部は、必ずしも、図1~図6に示すように、スポット状に形成する必要はなく、電極板本体の一端部において、電極リードの端面の全体や大部分を幅方向に覆うような幅広の形状(例えば、帯状)に形成してもよい。
電極板本体の一端部において、複数の溶融部を形成したり、溶融部を帯状などの幅広の形状に形成したりすることにより、溶接強度をさらに大きくすることもできる。
本発明の電極板は、電極リードと電極板本体との接合強度が高いため、各種電気化学素子用の電極板として有用である。 Further, the melted portion does not necessarily have to be formed in a spot shape as shown in FIGS. 1 to 6, and covers the whole or most of the end surface of the electrode lead in the width direction at one end of the electrode plate body. You may form in a wide shape (for example, strip | belt shape).
The welding strength can be further increased by forming a plurality of melted portions at one end of the electrode plate body or by forming the melted portions into a wide shape such as a band shape.
The electrode plate of the present invention is useful as an electrode plate for various electrochemical elements because of high bonding strength between the electrode lead and the electrode plate body.
電極板本体の一端部において、複数の溶融部を形成したり、溶融部を帯状などの幅広の形状に形成したりすることにより、溶接強度をさらに大きくすることもできる。
本発明の電極板は、電極リードと電極板本体との接合強度が高いため、各種電気化学素子用の電極板として有用である。 Further, the melted portion does not necessarily have to be formed in a spot shape as shown in FIGS. 1 to 6, and covers the whole or most of the end surface of the electrode lead in the width direction at one end of the electrode plate body. You may form in a wide shape (for example, strip | belt shape).
The welding strength can be further increased by forming a plurality of melted portions at one end of the electrode plate body or by forming the melted portions into a wide shape such as a band shape.
The electrode plate of the present invention is useful as an electrode plate for various electrochemical elements because of high bonding strength between the electrode lead and the electrode plate body.
電気化学素子は、第1電極としての上記の電気化学素子用電極板と、第1電極とは反対の極性の第2電極と、第1電極と第2電極との間に介在するセパレータとを含む。
電極板が使用される電気化学素子としては、電池の他、二次電池と同様の集電構造を有するキャパシタ(例えば、電気二重層キャパシタなど)などが例示できる。電池としては、アルカリ乾電池やリチウム一次電池などの一次電池、ニッケル水素蓄電池などのアルカリ二次電池、非水電解質二次電池(リチウムイオン二次電池など)などの二次電池が例示できる。 The electrochemical element includes the above-described electrode plate for an electrochemical element as a first electrode, a second electrode having a polarity opposite to the first electrode, and a separator interposed between the first electrode and the second electrode. Including.
Examples of the electrochemical element in which the electrode plate is used include a battery and a capacitor (for example, an electric double layer capacitor) having a current collecting structure similar to that of the secondary battery. Examples of the battery include primary batteries such as alkaline dry batteries and lithium primary batteries, alkaline secondary batteries such as nickel hydride storage batteries, and secondary batteries such as non-aqueous electrolyte secondary batteries (such as lithium ion secondary batteries).
電極板が使用される電気化学素子としては、電池の他、二次電池と同様の集電構造を有するキャパシタ(例えば、電気二重層キャパシタなど)などが例示できる。電池としては、アルカリ乾電池やリチウム一次電池などの一次電池、ニッケル水素蓄電池などのアルカリ二次電池、非水電解質二次電池(リチウムイオン二次電池など)などの二次電池が例示できる。 The electrochemical element includes the above-described electrode plate for an electrochemical element as a first electrode, a second electrode having a polarity opposite to the first electrode, and a separator interposed between the first electrode and the second electrode. Including.
Examples of the electrochemical element in which the electrode plate is used include a battery and a capacitor (for example, an electric double layer capacitor) having a current collecting structure similar to that of the secondary battery. Examples of the battery include primary batteries such as alkaline dry batteries and lithium primary batteries, alkaline secondary batteries such as nickel hydride storage batteries, and secondary batteries such as non-aqueous electrolyte secondary batteries (such as lithium ion secondary batteries).
以下に、電極板および電気化学素子の各構成要素について説明する。
電極板に含まれる電極板本体は、金属を含む集電体と、この表面に形成され、活物質を含む活物質層との積層体を含む。 Below, each component of an electrode plate and an electrochemical element is demonstrated.
The electrode plate main body included in the electrode plate includes a laminate of a current collector containing metal and an active material layer formed on the surface and containing an active material.
電極板に含まれる電極板本体は、金属を含む集電体と、この表面に形成され、活物質を含む活物質層との積層体を含む。 Below, each component of an electrode plate and an electrochemical element is demonstrated.
The electrode plate main body included in the electrode plate includes a laminate of a current collector containing metal and an active material layer formed on the surface and containing an active material.
本発明では、電極リードの金属成分と、少なくとも活物質(好ましくは活物質および集電体の金属成分)とが合金化されることにより溶融部が形成されるため、合金化可能な、電極リードに含まれる金属と、活物質や集電体に含まれる金属との組み合わせを適宜選択すればよい。電極リードに含まれる金属、集電体に含まれる金属および活物質の種類は、電気化学素子の種類、電極板が使用される電極の種類(正極(または陽極)もしくは負極(または陰極)のどちらか)などによっても左右される。
In the present invention, since the molten portion is formed by alloying the metal component of the electrode lead and at least the active material (preferably, the metal component of the active material and the current collector), the electrode lead can be alloyed. The combination of the metal contained in the metal and the metal contained in the active material or current collector may be selected as appropriate. The type of metal contained in the electrode lead, the metal contained in the current collector, and the active material can be either the type of electrochemical element or the type of electrode on which the electrode plate is used (positive electrode (or anode) or negative electrode (or cathode)). )) And so on.
電極リードに含まれる金属としては、例えば、銅、銅合金、ニッケル、ニッケル合金、アルミニウム、アルミニウム合金、銀、銀合金、金、金合金などが挙げられる。これらのうち、銅または銅合金などが好ましい。
Examples of the metal contained in the electrode lead include copper, copper alloy, nickel, nickel alloy, aluminum, aluminum alloy, silver, silver alloy, gold, and gold alloy. Of these, copper or a copper alloy is preferable.
集電体に含まれる金属は、電気化学素子の種類や電極の種類などに応じて選択され、例えば、銅、銅合金、ニッケル、ニッケル合金、アルミニウム、アルミニウム合金、ステンレス鋼などが例示できる。
The metal contained in the current collector is selected according to the type of electrochemical element or the type of electrode, and examples thereof include copper, copper alloy, nickel, nickel alloy, aluminum, aluminum alloy, and stainless steel.
活物質としては、集電体に含まれる上記の金属と合金化可能な金属、この金属の合金または金属化合物などが例示でき、電気化学素子の種類や電極の種類などに応じて選択される。
Examples of the active material include metals that can be alloyed with the above-described metals contained in the current collector, alloys of these metals, metal compounds, and the like, and are selected according to the type of electrochemical element, the type of electrode, and the like.
本発明の電極板は、電気化学素子のうち、特に、リチウムイオン電池などの非水電解質二次電池に使用するのに有用である。以下に、非水電解質二次電池を例に挙げて、電気化学素子の構成要素を説明する。
The electrode plate of the present invention is particularly useful for use in non-aqueous electrolyte secondary batteries such as lithium ion batteries among electrochemical elements. The constituent elements of the electrochemical device will be described below by taking a nonaqueous electrolyte secondary battery as an example.
非水電解質二次電池は、正極と、負極と、これらの間に介在するセパレータと、非水電解質とを備える。
非水電解質二次電池において、本発明の電極板は、負極として使用するのが好ましい。
負極は、集電体と、集電体の表面に形成された活物質層とを含む。活物質層は、集電体の一方の表面に形成してもよく、両方の表面に形成してもよい。 The nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator interposed therebetween, and a nonaqueous electrolyte.
In the nonaqueous electrolyte secondary battery, the electrode plate of the present invention is preferably used as a negative electrode.
The negative electrode includes a current collector and an active material layer formed on the surface of the current collector. The active material layer may be formed on one surface of the current collector, or may be formed on both surfaces.
非水電解質二次電池において、本発明の電極板は、負極として使用するのが好ましい。
負極は、集電体と、集電体の表面に形成された活物質層とを含む。活物質層は、集電体の一方の表面に形成してもよく、両方の表面に形成してもよい。 The nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator interposed therebetween, and a nonaqueous electrolyte.
In the nonaqueous electrolyte secondary battery, the electrode plate of the present invention is preferably used as a negative electrode.
The negative electrode includes a current collector and an active material layer formed on the surface of the current collector. The active material layer may be formed on one surface of the current collector, or may be formed on both surfaces.
負極集電体の材質としては、銅、銅合金などが例示できる。負極集電体の形態は特に制限されず、無孔性の金属箔であってもよく、多孔性であってもよい。負極集電体の厚さは、例えば、5~50μmの範囲から選択できる。
Examples of the material of the negative electrode current collector include copper and copper alloys. The form of the negative electrode current collector is not particularly limited, and may be a nonporous metal foil or may be porous. The thickness of the negative electrode current collector can be selected from a range of 5 to 50 μm, for example.
負極活物質層は、負極活物質で形成してもよく、負極活物質の他、結着剤、導電剤、増粘剤などを含有してもよい。
負極活物質としては、電極リードの金属成分と合金化可能で、かつ、リチウムイオンを可逆的に吸蔵および放出し得る各種材料、例えば、ケイ素、ケイ素合金、ケイ素化合物(ケイ素酸化物SiOx、ケイ素窒化物、ケイ素炭化物など)、スズ、スズ合金、スズ化合物(スズ酸化物SnOx、スズ窒化物、スズ炭化物など)などの他、Al、Znおよび/またはMgなどを含むリチウム合金などの合金系材料が例示できる。ケイ素酸化物およびスズ酸化物において、係数xは、0<x<2である。 The negative electrode active material layer may be formed of a negative electrode active material, and may contain a binder, a conductive agent, a thickener, and the like in addition to the negative electrode active material.
Examples of the negative electrode active material include various materials that can be alloyed with the metal component of the electrode lead and that can reversibly occlude and release lithium ions, such as silicon, silicon alloys, silicon compounds (silicon oxide SiOx, silicon nitride). Alloy, silicon carbide, etc.), tin, tin alloys, tin compounds (tin oxide SnOx, tin nitride, tin carbide, etc.), and alloy materials such as lithium alloys containing Al, Zn and / or Mg, etc. It can be illustrated. In silicon oxide and tin oxide, the coefficient x is 0 <x <2.
負極活物質としては、電極リードの金属成分と合金化可能で、かつ、リチウムイオンを可逆的に吸蔵および放出し得る各種材料、例えば、ケイ素、ケイ素合金、ケイ素化合物(ケイ素酸化物SiOx、ケイ素窒化物、ケイ素炭化物など)、スズ、スズ合金、スズ化合物(スズ酸化物SnOx、スズ窒化物、スズ炭化物など)などの他、Al、Znおよび/またはMgなどを含むリチウム合金などの合金系材料が例示できる。ケイ素酸化物およびスズ酸化物において、係数xは、0<x<2である。 The negative electrode active material layer may be formed of a negative electrode active material, and may contain a binder, a conductive agent, a thickener, and the like in addition to the negative electrode active material.
Examples of the negative electrode active material include various materials that can be alloyed with the metal component of the electrode lead and that can reversibly occlude and release lithium ions, such as silicon, silicon alloys, silicon compounds (silicon oxide SiOx, silicon nitride). Alloy, silicon carbide, etc.), tin, tin alloys, tin compounds (tin oxide SnOx, tin nitride, tin carbide, etc.), and alloy materials such as lithium alloys containing Al, Zn and / or Mg, etc. It can be illustrated. In silicon oxide and tin oxide, the coefficient x is 0 <x <2.
ケイ素合金としては、ケイ素とリチウムとを含む合金、ケイ素およびリチウムに加え、Al、Znおよび/またはMgなどを含む合金などが例示できる。
スズ合金としては、スズとリチウムとを含む合金、スズおよびリチウムに加え、Al、Znおよび/またはMgなどを含む合金などが例示できる。
これらの負極活物質は、一種を単独でまたは二種以上を組み合わせて使用できる。
負極活物質のうち、特に、ケイ素、ケイ素合金、ケイ素化合物などが好ましい。これらの中でも、少なくともケイ素とリチウムとを含む合金が好ましい。 Examples of the silicon alloy include an alloy containing silicon and lithium, an alloy containing Al, Zn, and / or Mg in addition to silicon and lithium.
Examples of the tin alloy include an alloy containing tin and lithium, an alloy containing Al, Zn, and / or Mg in addition to tin and lithium.
These negative electrode active materials can be used individually by 1 type or in combination of 2 or more types.
Of the negative electrode active materials, silicon, silicon alloys, silicon compounds, and the like are particularly preferable. Among these, an alloy containing at least silicon and lithium is preferable.
スズ合金としては、スズとリチウムとを含む合金、スズおよびリチウムに加え、Al、Znおよび/またはMgなどを含む合金などが例示できる。
これらの負極活物質は、一種を単独でまたは二種以上を組み合わせて使用できる。
負極活物質のうち、特に、ケイ素、ケイ素合金、ケイ素化合物などが好ましい。これらの中でも、少なくともケイ素とリチウムとを含む合金が好ましい。 Examples of the silicon alloy include an alloy containing silicon and lithium, an alloy containing Al, Zn, and / or Mg in addition to silicon and lithium.
Examples of the tin alloy include an alloy containing tin and lithium, an alloy containing Al, Zn, and / or Mg in addition to tin and lithium.
These negative electrode active materials can be used individually by 1 type or in combination of 2 or more types.
Of the negative electrode active materials, silicon, silicon alloys, silicon compounds, and the like are particularly preferable. Among these, an alloy containing at least silicon and lithium is preferable.
負極活物質層には、活物質の溶融効率を高める観点から、負極活物質層の表面にリチウム箔またはリチウム合金箔を貼り付けてもよい。貼り付けたリチウム箔や合金箔に含まれるリチウムは、適宜、負極活物質層に吸蔵される。
From the viewpoint of increasing the melting efficiency of the active material, a lithium foil or a lithium alloy foil may be attached to the surface of the negative electrode active material layer in the negative electrode active material layer. Lithium contained in the attached lithium foil or alloy foil is appropriately occluded in the negative electrode active material layer.
負極に電気的に接続される電極リードは、銅または銅合金を含むのが好ましい。
例えば、銅または銅合金を含む電極リードと、活物質層にケイ素やスズなどの元素とリチウムとを含む合金を活物質として含む電極板本体とを、電極板本体の一端部において、溶接する。この場合、活物質がリチウムを含むことにより、ケイ素やスズの単体に比べて、溶融温度が低くなり、溶融が進みやすくなる。そのため、主に活物質層を溶融するように溶融部を形成すると、溶融したケイ素やスズが、電極リードに含まれる銅または銅合金中に拡散する。銅や銅合金中に、ケイ素やスズが拡散すると、元々の銅や銅合金の溶融温度よりも溶融温度がさらに低くなるため、さらに溶融が進行しやすくなる。つまり、活物質層を主に溶融させることにより、活物質の溶融が進行しやすくなる上、さらに電極リードの金属成分の溶融効率も高まる。これにより、活物質および電極リードの溶融量が増加し、溶融部の大きさが大きくなる。 The electrode lead electrically connected to the negative electrode preferably contains copper or a copper alloy.
For example, an electrode lead including copper or a copper alloy and an electrode plate main body including an alloy containing lithium and an element such as silicon or tin as an active material are welded to one end of the electrode plate main body. In this case, when the active material contains lithium, the melting temperature becomes lower than that of silicon or tin alone, and the melting easily proceeds. Therefore, when the melted part is formed so as to mainly melt the active material layer, the melted silicon or tin diffuses into the copper or copper alloy contained in the electrode lead. When silicon or tin diffuses into copper or a copper alloy, the melting temperature becomes lower than the melting temperature of the original copper or copper alloy, so that the melting is further facilitated. That is, by mainly melting the active material layer, the melting of the active material is facilitated and the melting efficiency of the metal component of the electrode lead is further increased. Thereby, the melting amount of the active material and the electrode lead is increased, and the size of the melted portion is increased.
例えば、銅または銅合金を含む電極リードと、活物質層にケイ素やスズなどの元素とリチウムとを含む合金を活物質として含む電極板本体とを、電極板本体の一端部において、溶接する。この場合、活物質がリチウムを含むことにより、ケイ素やスズの単体に比べて、溶融温度が低くなり、溶融が進みやすくなる。そのため、主に活物質層を溶融するように溶融部を形成すると、溶融したケイ素やスズが、電極リードに含まれる銅または銅合金中に拡散する。銅や銅合金中に、ケイ素やスズが拡散すると、元々の銅や銅合金の溶融温度よりも溶融温度がさらに低くなるため、さらに溶融が進行しやすくなる。つまり、活物質層を主に溶融させることにより、活物質の溶融が進行しやすくなる上、さらに電極リードの金属成分の溶融効率も高まる。これにより、活物質および電極リードの溶融量が増加し、溶融部の大きさが大きくなる。 The electrode lead electrically connected to the negative electrode preferably contains copper or a copper alloy.
For example, an electrode lead including copper or a copper alloy and an electrode plate main body including an alloy containing lithium and an element such as silicon or tin as an active material are welded to one end of the electrode plate main body. In this case, when the active material contains lithium, the melting temperature becomes lower than that of silicon or tin alone, and the melting easily proceeds. Therefore, when the melted part is formed so as to mainly melt the active material layer, the melted silicon or tin diffuses into the copper or copper alloy contained in the electrode lead. When silicon or tin diffuses into copper or a copper alloy, the melting temperature becomes lower than the melting temperature of the original copper or copper alloy, so that the melting is further facilitated. That is, by mainly melting the active material layer, the melting of the active material is facilitated and the melting efficiency of the metal component of the electrode lead is further increased. Thereby, the melting amount of the active material and the electrode lead is increased, and the size of the melted portion is increased.
また、負極集電体も、電極リードと同様に、銅や銅合金を含むため、上記の活物質と電極リードの金属成分との合金化と同様に、集電体の銅や銅合金と、活物質、ひいては電極リードとの合金化が進行し易くなる。そのため、集電体の溶融量も増加することになり、溶融部の大きさはさらに大きくなる。
Moreover, since the negative electrode current collector also contains copper and a copper alloy, as in the case of the electrode lead, like the alloying of the active material and the metal component of the electrode lead, the current collector copper and copper alloy, Alloying with the active material, and hence the electrode lead, is likely to proceed. Therefore, the amount of melting of the current collector is also increased, and the size of the melted portion is further increased.
しかも、このような合金化の際には、活物質層、集電体および電極リードの端面だけでなく、端面側の一部も一緒に合金化される。そのため、接合強度を大幅に高めることができる。
Moreover, in the case of such alloying, not only the end surfaces of the active material layer, the current collector and the electrode lead but also a part of the end surface side are alloyed together. Therefore, the bonding strength can be greatly increased.
このようにして形成される溶融部は、銅とケイ素やスズとの合金を含む。好ましい態様では、溶融部は、銅とケイ素との合金を含む。このような合金の組成は特に制限されないが、合金が、Cu5Siを含むことが好ましい。
The melted portion thus formed contains an alloy of copper and silicon or tin. In a preferred embodiment, the molten part contains an alloy of copper and silicon. The composition of such an alloy is not particularly limited, but the alloy preferably contains Cu 5 Si.
Cu5Siを含む合金は、X線回折スペクトルにおいて、Cu5Siに由来するピークを、2θ=68°付近および153°付近に有する。2θ=68°付近におけるピークは、2θ=153°付近のピークに比べて強度が高く出やすいため、2θ=68°付近のピークを確認することにより、Cu5Siの生成の有無や程度を調べることができる。
従来の方法で集電体の端面と電極リードの端面とを溶接することにより溶融部を形成した場合には、X線回折スペクトルにおいて、2θ=68°付近および153°付近におけるピークはほとんど観察されない。 Alloy containing Cu 5 Si has the X-ray diffraction spectrum, the peak derived from the Cu 5 Si, around 2 [Theta] = 68 ° and around 153 °. Since the peak near 2θ = 68 ° is higher in intensity than the peak near 2θ = 153 °, the presence or extent of Cu 5 Si is examined by confirming the peak near 2θ = 68 °. be able to.
When the melted part is formed by welding the end face of the current collector and the end face of the electrode lead by a conventional method, peaks at around 2θ = 68 ° and around 153 ° are hardly observed in the X-ray diffraction spectrum. .
従来の方法で集電体の端面と電極リードの端面とを溶接することにより溶融部を形成した場合には、X線回折スペクトルにおいて、2θ=68°付近および153°付近におけるピークはほとんど観察されない。 Alloy containing Cu 5 Si has the X-ray diffraction spectrum, the peak derived from the Cu 5 Si, around 2 [Theta] = 68 ° and around 153 °. Since the peak near 2θ = 68 ° is higher in intensity than the peak near 2θ = 153 °, the presence or extent of Cu 5 Si is examined by confirming the peak near 2θ = 68 °. be able to.
When the melted part is formed by welding the end face of the current collector and the end face of the electrode lead by a conventional method, peaks at around 2θ = 68 ° and around 153 ° are hardly observed in the X-ray diffraction spectrum. .
負極活物質層は、負極活物質、結着剤および分散媒を含む負極スラリーを用いて形成できる。負極スラリーは、必要に応じて、さらに増粘剤、導電材などを含有してもよい。負極活物質層は、これらの成分を含む負極スラリーを調製し、負極集電体の表面に塗布することにより形成できる。
また、負極活物質の種類によっては、真空蒸着法などの蒸着法、スパッタリング法、CVD法などの気相法により負極活物質を集電体表面に堆積させて、負極活物質の薄膜を形成することにより、負極活物質層を形成してもよい。 The negative electrode active material layer can be formed using a negative electrode slurry containing a negative electrode active material, a binder, and a dispersion medium. The negative electrode slurry may further contain a thickener, a conductive material, and the like as necessary. The negative electrode active material layer can be formed by preparing a negative electrode slurry containing these components and applying it to the surface of the negative electrode current collector.
Depending on the type of the negative electrode active material, a negative electrode active material is deposited on the surface of the current collector by a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or a CVD method to form a thin film of the negative electrode active material. Thus, a negative electrode active material layer may be formed.
また、負極活物質の種類によっては、真空蒸着法などの蒸着法、スパッタリング法、CVD法などの気相法により負極活物質を集電体表面に堆積させて、負極活物質の薄膜を形成することにより、負極活物質層を形成してもよい。 The negative electrode active material layer can be formed using a negative electrode slurry containing a negative electrode active material, a binder, and a dispersion medium. The negative electrode slurry may further contain a thickener, a conductive material, and the like as necessary. The negative electrode active material layer can be formed by preparing a negative electrode slurry containing these components and applying it to the surface of the negative electrode current collector.
Depending on the type of the negative electrode active material, a negative electrode active material is deposited on the surface of the current collector by a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or a CVD method to form a thin film of the negative electrode active material. Thus, a negative electrode active material layer may be formed.
結着剤としては、ポリフッ化ビニリデン(PVDF)などのフッ素樹脂;ポリアクリル酸メチル、エチレン-メタクリル酸メチル共重合体などのアクリル樹脂;スチレン-ブタジエンゴム、アクリルゴムまたはこれらの変性体などのゴム状材料が例示できる。
結着剤の割合は、活物質100質量部当たり、例えば、0.1~10質量部、好ましくは1~5質量部である。 As binders, fluorine resins such as polyvinylidene fluoride (PVDF); acrylic resins such as polymethyl acrylate and ethylene-methyl methacrylate copolymer; rubbers such as styrene-butadiene rubber, acrylic rubber, or modified products thereof The material can be exemplified.
The ratio of the binder is, for example, 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of the active material.
結着剤の割合は、活物質100質量部当たり、例えば、0.1~10質量部、好ましくは1~5質量部である。 As binders, fluorine resins such as polyvinylidene fluoride (PVDF); acrylic resins such as polymethyl acrylate and ethylene-methyl methacrylate copolymer; rubbers such as styrene-butadiene rubber, acrylic rubber, or modified products thereof The material can be exemplified.
The ratio of the binder is, for example, 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of the active material.
負極スラリーに含まれる分散媒としては、例えば、水、エタノールなどのアルコール、テトラヒドロフランなどのエーテル、N-メチル-2-ピロリドン(NMP)、またはこれらの混合溶媒などが例示できる。
Examples of the dispersion medium contained in the negative electrode slurry include water, alcohols such as ethanol, ethers such as tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), or a mixed solvent thereof.
負極スラリーは、プラネタリーミキサなどの慣用の混合機または分散機などを用いる方法により調製できる。また、負極スラリーは、例えば、各種コーターなどを利用する慣用の塗布方法などにより負極集電体表面に塗布できる。負極スラリーの塗膜は、通常、乾燥され、圧延に供される。
The negative electrode slurry can be prepared by a method using a conventional mixer such as a planetary mixer or a disperser. The negative electrode slurry can be applied to the surface of the negative electrode current collector by, for example, a conventional application method using various coaters. The coating film of the negative electrode slurry is usually dried and subjected to rolling.
導電剤としては、カーボンブラック;金属繊維、炭素繊維などの導電性繊維;フッ化カーボンなどが挙げられる。導電剤の割合は、例えば、活物質100質量部当たり、例えば、0.1~7質量部である。
Examples of the conductive agent include carbon black; conductive fibers such as metal fibers and carbon fibers; and carbon fluoride. The ratio of the conductive agent is, for example, 0.1 to 7 parts by mass per 100 parts by mass of the active material.
増粘剤としては、例えば、カルボキシメチルセルロース(CMC)などのセルロース誘導体;ポリエチレングリコールなどのポリC2-4アルキレングリコールなどが挙げられる。増粘剤の割合は、例えば、活物質100質量部当たり、例えば、0.1~10質量部である。
負極活物質層の厚さは、例えば、5~200μm、好ましくは5~100μmである。堆積により形成される負極活物質層の厚さは、例えば、5~50μmまたは5~30μmである。 Examples of the thickener include cellulose derivatives such as carboxymethyl cellulose (CMC); poly C 2-4 alkylene glycol such as polyethylene glycol. The ratio of the thickener is, for example, 0.1 to 10 parts by mass per 100 parts by mass of the active material.
The thickness of the negative electrode active material layer is, for example, 5 to 200 μm, preferably 5 to 100 μm. The thickness of the negative electrode active material layer formed by deposition is, for example, 5 to 50 μm or 5 to 30 μm.
負極活物質層の厚さは、例えば、5~200μm、好ましくは5~100μmである。堆積により形成される負極活物質層の厚さは、例えば、5~50μmまたは5~30μmである。 Examples of the thickener include cellulose derivatives such as carboxymethyl cellulose (CMC); poly C 2-4 alkylene glycol such as polyethylene glycol. The ratio of the thickener is, for example, 0.1 to 10 parts by mass per 100 parts by mass of the active material.
The thickness of the negative electrode active material layer is, for example, 5 to 200 μm, preferably 5 to 100 μm. The thickness of the negative electrode active material layer formed by deposition is, for example, 5 to 50 μm or 5 to 30 μm.
正極は、集電体と、集電体の表面に形成された活物質層とを含む。活物質層は、集電体の一方の表面に形成してもよく、両方の表面に形成してもよい。
正極集電体の材質としては、例えば、ステンレス鋼、アルミニウム、アルミニウム合金、チタンなどが挙げられる。正極集電体の形態および厚さは、負極集電体と同様である。 The positive electrode includes a current collector and an active material layer formed on the surface of the current collector. The active material layer may be formed on one surface of the current collector, or may be formed on both surfaces.
Examples of the material of the positive electrode current collector include stainless steel, aluminum, aluminum alloy, and titanium. The form and thickness of the positive electrode current collector are the same as those of the negative electrode current collector.
正極集電体の材質としては、例えば、ステンレス鋼、アルミニウム、アルミニウム合金、チタンなどが挙げられる。正極集電体の形態および厚さは、負極集電体と同様である。 The positive electrode includes a current collector and an active material layer formed on the surface of the current collector. The active material layer may be formed on one surface of the current collector, or may be formed on both surfaces.
Examples of the material of the positive electrode current collector include stainless steel, aluminum, aluminum alloy, and titanium. The form and thickness of the positive electrode current collector are the same as those of the negative electrode current collector.
正極活物質層は、正極活物質の他、結着剤、導電剤、増粘剤などを含有してもよい。正極活物質層は、これらの成分を含む正極スラリーを用いて、負極活物質層と同様の方法により形成できる。正極スラリーに含まれる各成分としては、負極スラリーの項で例示したものが使用でき、各成分の含有量は、負極スラリーの場合と同様の範囲から選択できる。また、正極活物質層の厚さは、負極活物質層の厚さと同様の範囲から選択できる。
The positive electrode active material layer may contain a binder, a conductive agent, a thickener and the like in addition to the positive electrode active material. The positive electrode active material layer can be formed by a method similar to that of the negative electrode active material layer, using a positive electrode slurry containing these components. As each component contained in a positive electrode slurry, what was illustrated by the term of the negative electrode slurry can be used, and content of each component can be selected from the same range as the case of a negative electrode slurry. The thickness of the positive electrode active material layer can be selected from the same range as the thickness of the negative electrode active material layer.
正極活物質としては、公知の非水電解質二次電池正極活物質が使用でき、その中でも、リチウム遷移金属酸化物が好ましく用いられる。正極活物質は、一種を単独でまたは二種以上を組み合わせて使用できる。
As the positive electrode active material, known nonaqueous electrolyte secondary battery positive electrode active materials can be used, and among these, lithium transition metal oxides are preferably used. A positive electrode active material can be used individually by 1 type or in combination of 2 or more types.
リチウム遷移金属酸化物としては、具体的には、例えば、LixMa
1-yMb
yO2(0.9≦x≦1.1、0≦y≦0.7、MaはNi、Co、Mn、Fe、Ti等からなる群より選択される少なくとも1種、MbはMa以外の少なくとも1種の金属元素)などの他、LiMn2O4、LiFePO4、LiCoPO4、LiMnPO4などが挙げられる。
As the lithium transition metal oxide, specifically, for example, Li x M a 1-y M b y O 2 (0.9 ≦ x ≦ 1.1, 0 ≦ y ≦ 0.7, M a is Ni , Co, Mn, Fe, at least one selected from the group consisting of Ti or the like, M b other such as at least one metal element) other than M a is, LiMn 2 O 4, LiFePO 4 , LiCoPO 4, LiMnPO 4 and so on.
リチウム遷移金属酸化物としては、例えば、コバルト酸リチウムおよびその変性体、ニッケル酸リチウムおよびその変性体、マンガン酸リチウムおよびその変性体などが好ましい。このようなリチウム遷移金属酸化物としては、上記式のうち、LixNi1-yMc
yO2(0.9≦x≦1.1、0≦y≦0.7、Mcは、Co、Mn、Fe、Ti、Al、Mg、Ca、Sr、Zn、Y、Yb、NbおよびAsからなる群より選択される少なくとも1種)で表されるリチウムニッケル酸化物、LixCo1-yM2
yO2(0.9≦x≦1.1、0≦y≦0.7、M2は、Ni、Mn、Fe、Ti、Al、Mg、Ca、Sr、Zn、Y、Yb、NbおよびAsからなる群より選択される少なくとも1種)で表されるリチウムコバルト酸化物、リチウムマンガン酸化物などが例示できる。
As the lithium transition metal oxide, for example, lithium cobaltate and a modified product thereof, lithium nickelate and a modified product thereof, lithium manganate and a modified product thereof are preferable. Examples of such a lithium transition metal oxide, of the above formula, Li x Ni 1-y M c y O 2 (0.9 ≦ x ≦ 1.1,0 ≦ y ≦ 0.7, M c is Li x Co 1− , represented by lithium nickel oxide represented by at least one selected from the group consisting of Co, Mn, Fe, Ti, Al, Mg, Ca, Sr, Zn, Y, Yb, Nb, and As) y M 2 y O 2 (0.9 ≦ x ≦ 1.1, 0 ≦ y ≦ 0.7, M 2 is Ni, Mn, Fe, Ti, Al, Mg, Ca, Sr, Zn, Y, Yb , At least one selected from the group consisting of Nb and As).
リチウムニッケル酸化物において、yは、好ましくは0.05≦y≦0.5である。リチウムコバルト酸化物において、yは、好ましくは0≦y≦0.3である。
上記式のリチウム遷移金属酸化物のうち、LiNi1/2Mn1/2O2、LiNiO2、LiNi1/2Fe1/2O2、LiNi0.8Co0.15Al0.05O2、LiNi1/3Mn1/3Co1/3O2、LiCoO2、LiMnO2などが好ましい。 In the lithium nickel oxide, y is preferably 0.05 ≦ y ≦ 0.5. In the lithium cobalt oxide, y is preferably 0 ≦ y ≦ 0.3.
Among the lithium transition metal oxides of the above formula, LiNi 1/2 Mn 1/2 O 2 , LiNiO 2 , LiNi 1/2 Fe 1/2 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 1/3 Mn 1/3 Co 1/3 O 2 , LiCoO 2 , LiMnO 2 and the like are preferable.
上記式のリチウム遷移金属酸化物のうち、LiNi1/2Mn1/2O2、LiNiO2、LiNi1/2Fe1/2O2、LiNi0.8Co0.15Al0.05O2、LiNi1/3Mn1/3Co1/3O2、LiCoO2、LiMnO2などが好ましい。 In the lithium nickel oxide, y is preferably 0.05 ≦ y ≦ 0.5. In the lithium cobalt oxide, y is preferably 0 ≦ y ≦ 0.3.
Among the lithium transition metal oxides of the above formula, LiNi 1/2 Mn 1/2 O 2 , LiNiO 2 , LiNi 1/2 Fe 1/2 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 1/3 Mn 1/3 Co 1/3 O 2 , LiCoO 2 , LiMnO 2 and the like are preferable.
セパレータとしては、樹脂製の、微多孔フィルム、不織布または織布などの他、金属酸化物などのフィラーをベースとする無機多孔膜などが使用できる。セパレータは、複数の多孔質層の積層体であってもよい。各多孔質層は、微多孔フィルムなどの、単層のセパレータと同様のもので形成でき、種類の異なる複数の多孔質層を組み合わせてもよい。微多孔フィルム、不織布セパレータを構成する樹脂としては、例えば、ポリエチレン、ポリプロピレンなどのポリオレフィン;ポリアミド;ポリアミドイミド;ポリイミド;セルロースなどが例示できる。無機多孔膜は、フィラーとフィラーを結着する樹脂バインダーとを含む。
セパレータの厚みは、例えば、5~100μmまたは5~50μmである。 As the separator, a resin-made microporous film, a nonwoven fabric, a woven fabric, or the like, or an inorganic porous film based on a filler such as a metal oxide can be used. The separator may be a laminate of a plurality of porous layers. Each porous layer can be formed of a single-layer separator such as a microporous film, and a plurality of different types of porous layers may be combined. Examples of the resin constituting the microporous film and the nonwoven fabric separator include polyolefins such as polyethylene and polypropylene; polyamide; polyamideimide; polyimide; cellulose and the like. The inorganic porous film includes a filler and a resin binder that binds the filler.
The thickness of the separator is, for example, 5 to 100 μm or 5 to 50 μm.
セパレータの厚みは、例えば、5~100μmまたは5~50μmである。 As the separator, a resin-made microporous film, a nonwoven fabric, a woven fabric, or the like, or an inorganic porous film based on a filler such as a metal oxide can be used. The separator may be a laminate of a plurality of porous layers. Each porous layer can be formed of a single-layer separator such as a microporous film, and a plurality of different types of porous layers may be combined. Examples of the resin constituting the microporous film and the nonwoven fabric separator include polyolefins such as polyethylene and polypropylene; polyamide; polyamideimide; polyimide; cellulose and the like. The inorganic porous film includes a filler and a resin binder that binds the filler.
The thickness of the separator is, for example, 5 to 100 μm or 5 to 50 μm.
非水電解質二次電池において、非水電解質としては、リチウムイオン伝導性を有する非水電解質が使用される。非水電解質は、非水溶媒と、非水溶媒に溶解したリチウム塩とを含む。
In the non-aqueous electrolyte secondary battery, a non-aqueous electrolyte having lithium ion conductivity is used as the non-aqueous electrolyte. The non-aqueous electrolyte includes a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.
非水溶媒としては、プロピレンカーボネート、エチレンカーボネート(EC)などの環状炭酸エステル;ジエチルカーボネート、エチルメチルカーボネート(EMC)、ジメチルカーボネートなどの鎖状炭酸エステル;γ-ブチロラクトン、γ-バレロラクトンなどの環状カルボン酸エステルなどが例示できる。これらの非水溶媒は、1種を単独でまたは2種以上を組み合わせて使用できる。
Non-aqueous solvents include cyclic carbonates such as propylene carbonate and ethylene carbonate (EC); chain carbonates such as diethyl carbonate, ethylmethyl carbonate (EMC) and dimethyl carbonate; cyclic esters such as γ-butyrolactone and γ-valerolactone Examples thereof include carboxylic acid esters. These non-aqueous solvents can be used alone or in combination of two or more.
リチウム塩としては、例えば、LiPF6、LiBF4、LiClO4、LiAsF6、LiCF3SO3、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiC(SO2CF3)3などが挙げられる。リチウム塩は、1種を単独でまたは2種以上を組み合わせて使用できる。非水電解質中のリチウム塩の濃度は、例えば、0.5~1.8mol/Lである。
Examples of the lithium salt include LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 , LiC (SO 2 CF 3 3 ). A lithium salt can be used individually by 1 type or in combination of 2 or more types. The concentration of the lithium salt in the nonaqueous electrolyte is, for example, 0.5 to 1.8 mol / L.
非水電解質には、公知の添加剤、例えば、ビニレンカーボネートなどのビニレンカーボネート化合物などを添加してもよい。
A known additive such as a vinylene carbonate compound such as vinylene carbonate may be added to the non-aqueous electrolyte.
非水電解質二次電池は、電池の形状などに応じて、公知の方法により製造できる。円筒型電池または角型電池では、例えば、正極と、負極と、これらの間に配されるセパレータとを捲回して電極群を形成し、電極群および電解質を電池ケースに収容することにより製造できる。
The nonaqueous electrolyte secondary battery can be manufactured by a known method according to the shape of the battery. In a cylindrical battery or a rectangular battery, for example, a positive electrode, a negative electrode, and a separator disposed between them are wound to form an electrode group, and the electrode group and the electrolyte can be accommodated in a battery case. .
電極群は、捲回したものに限らず、積層したもの、またはつづら折りにしたものであってもよい。電極群の形状は、電池または電池ケースの形状に応じて、円筒形、捲回軸に垂直な端面が長円形である扁平形であってもよい。
The electrode group is not limited to a wound one, but may be a laminated one or a folded one. The shape of the electrode group may be a cylindrical shape or a flat shape having an oval end surface perpendicular to the winding axis, depending on the shape of the battery or battery case.
電池ケース材料としては、アルミニウム、アルミニウム合金(マンガン、銅等などの金属を微量含有する合金など)、鋼鈑などが使用できる。
As the battery case material, aluminum, an aluminum alloy (such as an alloy containing a trace amount of a metal such as manganese or copper), a steel plate, or the like can be used.
図9は、本発明の一実施形態に係る円筒型非水電解質二次電池を概略的に示す縦断面図である。
円筒型非水電解質二次電池10は、有底円筒型電池ケース16と、電池ケース16内に収容された電極群14および図示しない非水電解質とを具備し、電池ケース16の開口部は、封口体18で封口されている。 FIG. 9 is a longitudinal sectional view schematically showing a cylindrical nonaqueous electrolyte secondary battery according to an embodiment of the present invention.
The cylindrical non-aqueous electrolytesecondary battery 10 includes a bottomed cylindrical battery case 16, an electrode group 14 accommodated in the battery case 16, and a non-aqueous electrolyte (not shown). Sealed with a sealing body 18.
円筒型非水電解質二次電池10は、有底円筒型電池ケース16と、電池ケース16内に収容された電極群14および図示しない非水電解質とを具備し、電池ケース16の開口部は、封口体18で封口されている。 FIG. 9 is a longitudinal sectional view schematically showing a cylindrical nonaqueous electrolyte secondary battery according to an embodiment of the present invention.
The cylindrical non-aqueous electrolyte
より詳細には、電極群14は、正極11と負極12とを、これらの間に、セパレータ13を介在させて渦捲状に捲回することにより形成されている。電極群14は、上面に上部絶縁板15aを配するとともに、底面に下部絶縁板15bを配した状態で、電池ケース16の内部に収納される。
More specifically, the electrode group 14 is formed by winding the positive electrode 11 and the negative electrode 12 in a vortex shape with a separator 13 interposed therebetween. The electrode group 14 is housed inside the battery case 16 with the upper insulating plate 15a disposed on the upper surface and the lower insulating plate 15b disposed on the bottom surface.
電極群14の上部より導出した正極リード11aは、電池ケース16の開口部を封口する封口体18に電気的に接続される。一方、電極群14の下部より導出した負極リード12aは、電池ケース16の内底面に電気的に接続される。このとき、負極リード12aは、電極群14の負極12の一端部において、負極12が有する負極活物質層の端面と負極リード12aの端面とを溶接することにより形成される溶融部で、負極12と電気的に接続されている。
The positive electrode lead 11 a led out from the upper part of the electrode group 14 is electrically connected to a sealing body 18 that seals the opening of the battery case 16. On the other hand, the negative electrode lead 12 a led out from the lower part of the electrode group 14 is electrically connected to the inner bottom surface of the battery case 16. At this time, the negative electrode lead 12a is a molten portion formed by welding the end surface of the negative electrode active material layer included in the negative electrode 12 and the end surface of the negative electrode lead 12a at one end portion of the negative electrode 12 of the electrode group 14. And are electrically connected.
非水電解質は、電極群14を電池ケース16に収納した後に、所定量注液される。非水電解質を注液した後、電池ケース16の開口部に、封口ガスケット17を周縁に取り付けた封口体18が挿入される。そして、電池ケース16の開口部を内方向に折り曲げるようにかしめ封口することにより、非水電解質二次電池10を得ることができる。
The nonaqueous electrolyte is injected into the battery case 16 after the electrode group 14 is stored in a predetermined amount. After injecting the nonaqueous electrolyte, a sealing body 18 having a sealing gasket 17 attached to the periphery is inserted into the opening of the battery case 16. And the nonaqueous electrolyte secondary battery 10 can be obtained by crimping and sealing so that the opening part of the battery case 16 may be bent inward.
(電気化学素子用電極板の製造方法)
非水電解質二次電池などの電極として使用される、電気化学素子用電極板の製造方法は、下記の工程(i)~(iii)を含む。
(i)金属を含む帯状の集電体と、集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体を準備する工程、
(ii)活物質層の一部の表面に、電極板本体の一端部と、金属を含む電極リードの一端部とが近接するように、電極リードを配置する工程、および
(iii)電極板本体の一端部において、少なくとも活物質層の端面と、電極リードの端面とを溶接することにより、少なくとも活物質と、電極リードの金属成分との合金を含み、かつ電極板本体と、電極リードとを、電気的に接続する溶融部を形成する工程。
そして、上記製造方法では、積層体の厚さ方向における溶融部の厚さを、積層体および電極リードの合計厚さ以上とする。 (Method for producing electrode plate for electrochemical element)
The method for producing an electrode plate for an electrochemical element used as an electrode for a nonaqueous electrolyte secondary battery includes the following steps (i) to (iii).
(I) a step of preparing an electrode plate body including a laminate of a band-shaped current collector containing a metal and an active material layer formed on the surface of the current collector and containing an active material;
(Ii) a step of arranging the electrode lead so that one end of the electrode plate main body and one end of the electrode lead containing metal are close to a part of the surface of the active material layer; and (iii) the electrode plate main body At least one end portion of the active material layer and the end surface of the electrode lead are welded to each other, thereby including an alloy of at least the active material and the metal component of the electrode lead, and the electrode plate body and the electrode lead. And a step of forming a melting portion to be electrically connected.
And in the said manufacturing method, the thickness of the fusion | melting part in the thickness direction of a laminated body shall be more than the total thickness of a laminated body and an electrode lead.
非水電解質二次電池などの電極として使用される、電気化学素子用電極板の製造方法は、下記の工程(i)~(iii)を含む。
(i)金属を含む帯状の集電体と、集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体を準備する工程、
(ii)活物質層の一部の表面に、電極板本体の一端部と、金属を含む電極リードの一端部とが近接するように、電極リードを配置する工程、および
(iii)電極板本体の一端部において、少なくとも活物質層の端面と、電極リードの端面とを溶接することにより、少なくとも活物質と、電極リードの金属成分との合金を含み、かつ電極板本体と、電極リードとを、電気的に接続する溶融部を形成する工程。
そして、上記製造方法では、積層体の厚さ方向における溶融部の厚さを、積層体および電極リードの合計厚さ以上とする。 (Method for producing electrode plate for electrochemical element)
The method for producing an electrode plate for an electrochemical element used as an electrode for a nonaqueous electrolyte secondary battery includes the following steps (i) to (iii).
(I) a step of preparing an electrode plate body including a laminate of a band-shaped current collector containing a metal and an active material layer formed on the surface of the current collector and containing an active material;
(Ii) a step of arranging the electrode lead so that one end of the electrode plate main body and one end of the electrode lead containing metal are close to a part of the surface of the active material layer; and (iii) the electrode plate main body At least one end portion of the active material layer and the end surface of the electrode lead are welded to each other, thereby including an alloy of at least the active material and the metal component of the electrode lead, and the electrode plate body and the electrode lead. And a step of forming a melting portion to be electrically connected.
And in the said manufacturing method, the thickness of the fusion | melting part in the thickness direction of a laminated body shall be more than the total thickness of a laminated body and an electrode lead.
工程(i)において、電極板本体は、集電体の表面に活物質層を積層して積層体を形成することにより準備できる。積層体は、上記の非水電解質二次電池における負極の形成方法に準じて形成できる。
In step (i), the electrode plate body can be prepared by laminating an active material layer on the surface of the current collector to form a laminate. A laminated body can be formed according to the formation method of the negative electrode in said nonaqueous electrolyte secondary battery.
工程(ii)では、工程(i)で準備された電極板本体の活物質層の一部の表面に電極リードを配置する。このとき、次工程(iii)で溶融部を形成しやすいように、電極板本体の一端部と、金属を含む電極リードの一端部とが近接するように、電極リードを活物質層の表面に配置する。次工程(iii)では、電極板本体のうち、少なくとも活物質層の端面と、電極リードの端面とを溶接するため、工程(ii)では、少なくとも活物質層の端面と電極リードの端面とを近接させる。このとき、これらの端面とともに、集電体の端面を近接させてもよい。
In step (ii), electrode leads are arranged on a part of the surface of the active material layer of the electrode plate body prepared in step (i). At this time, the electrode lead is placed on the surface of the active material layer so that one end of the electrode plate body and one end of the electrode lead containing metal are close to each other so that a melted part can be easily formed in the next step (iii). Deploy. In the next step (iii), at least the end surface of the active material layer and the end surface of the electrode lead in the electrode plate main body are welded. Therefore, in step (ii), at least the end surface of the active material layer and the end surface of the electrode lead are Make it close. At this time, the end faces of the current collector may be brought close together with these end faces.
工程(ii)において、電極リードは、長手方向の一端部と電極板本体の一端部とが近接するように配置してもよく、図5に示されるように、短手方向の一端部と電極板本体の一端部とが近接するように配置してもよい。好ましい態様では、電極リードの長手方向の一端部と電極板本体の一端部とを近接させる。
In step (ii), the electrode lead may be arranged so that one end in the longitudinal direction and one end of the electrode plate main body are close to each other. As shown in FIG. You may arrange | position so that the one end part of a board main body may adjoin. In a preferred embodiment, one end of the electrode lead in the longitudinal direction and one end of the electrode plate main body are brought close to each other.
工程(iii)では、電極板本体の一端部において、少なくとも活物質層の端面と電極リードの端面とを溶接させることにより溶融部を形成する。本発明では、工程(iii)において、電極板本体の構成成分のうち、少なくとも活物質と、電極リードの金属成分との合金を含む溶融部を形成する。そして、形成される溶融部の厚さを、積層体および電極リードの合計厚さ以上とする。そのため、前述のように、電極板本体と電極リードとを、極めて高い接合強度で接合できる。
In step (iii), at least one end surface of the active material layer and an end surface of the electrode lead are welded to one end portion of the electrode plate body to form a melted portion. In the present invention, in the step (iii), a molten part including at least an active material and a metal component of the electrode lead among the constituent components of the electrode plate body is formed. And let the thickness of the fusion | melting part formed be more than the total thickness of a laminated body and an electrode lead. Therefore, as described above, the electrode plate body and the electrode lead can be bonded with extremely high bonding strength.
溶接の方法は、特に制限されず、電極リードと電極板本体とを接合するための公知の溶接方法などが採用できる。具体的には、TIG溶接、プラズマ溶接、被覆アーク溶接などのアーク溶接;電子ビーム溶接;レーザー溶接などが例示できる。これらの溶接方法のうち、アーク溶接、中でも、TIG溶接やプラズマ溶接などの非消耗電極式アーク溶接、特に、プラズマ溶接が好ましい。
なお、溶接により溶融部が形成されるメカニズムは、前述の通りである。 The welding method is not particularly limited, and a known welding method for joining the electrode lead and the electrode plate body can be employed. Specific examples include arc welding such as TIG welding, plasma welding, and covering arc welding; electron beam welding; laser welding. Among these welding methods, arc welding, particularly non-consumable electrode type arc welding such as TIG welding and plasma welding, particularly plasma welding is preferable.
In addition, the mechanism in which a fusion | melting part is formed by welding is as above-mentioned.
なお、溶接により溶融部が形成されるメカニズムは、前述の通りである。 The welding method is not particularly limited, and a known welding method for joining the electrode lead and the electrode plate body can be employed. Specific examples include arc welding such as TIG welding, plasma welding, and covering arc welding; electron beam welding; laser welding. Among these welding methods, arc welding, particularly non-consumable electrode type arc welding such as TIG welding and plasma welding, particularly plasma welding is preferable.
In addition, the mechanism in which a fusion | melting part is formed by welding is as above-mentioned.
以下、本発明を実施例および比較例に基づいて具体的に説明するが、本発明は以下の実施例に限定されるものではない。
(実施例1)
以下のようにして、図1に示す構造のリチウムイオン二次電池用電極板を作製した。
集電体1bとしての厚さ40μmの銅箔の両方の表面に、珪素酸化物を真空蒸着することにより、厚さ20μmの活物質層1aを形成することにより積層体を形成した。 EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to a following example.
Example 1
A lithium ion secondary battery electrode plate having the structure shown in FIG. 1 was produced as follows.
A laminated body was formed by forming a 20 μm thickactive material layer 1a by vacuum-depositing silicon oxide on both surfaces of a 40 μm thick copper foil as the current collector 1b.
(実施例1)
以下のようにして、図1に示す構造のリチウムイオン二次電池用電極板を作製した。
集電体1bとしての厚さ40μmの銅箔の両方の表面に、珪素酸化物を真空蒸着することにより、厚さ20μmの活物質層1aを形成することにより積層体を形成した。 EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to a following example.
Example 1
A lithium ion secondary battery electrode plate having the structure shown in FIG. 1 was produced as follows.
A laminated body was formed by forming a 20 μm thick
さらに、溶融効率を向上させるために、双方の活物質層1aの表面に、厚さ10μmのリチウム箔を貼り付けた。次いで、リチウム箔を貼り付けた積層体を、長さ300mm×幅60mmの帯状に裁断して、厚み80μmの電極板本体1を作製した。そして、厚みが100μm、長さ90mm、幅5mmの銅からなる電極リード2を、電極板本体1の一方の活物質層1aの表面に、電極リード2の長手方向の一端部と、電極板本体1の一端部とが近接するように配置した。
Furthermore, in order to improve the melting efficiency, lithium foil having a thickness of 10 μm was pasted on the surfaces of both active material layers 1a. Subsequently, the laminated body to which the lithium foil was attached was cut into a strip shape having a length of 300 mm and a width of 60 mm to produce an electrode plate body 1 having a thickness of 80 μm. Then, an electrode lead 2 made of copper having a thickness of 100 μm, a length of 90 mm, and a width of 5 mm is disposed on the surface of one active material layer 1a of the electrode plate main body 1, on one end in the longitudinal direction of the electrode lead 2, and the electrode plate main body 1 was arranged so as to be close to one end.
次いで、電極板本体1の一端部において、プラズマ溶接により、電極板本体1の活物質層1aを主に溶融させることにより、電極板本体1の端面と電極リード2の端面とを溶接して、スポット状に1つの溶融部3を形成した。溶融部3は、図1に示すように、電極板本体1の一端部において、この一端部を溶融した状態で積層体および電極リードの端面全体を覆うように形成されていた。
Next, at one end of the electrode plate body 1, the end surface of the electrode plate body 1 and the end surface of the electrode lead 2 are welded by mainly melting the active material layer 1a of the electrode plate body 1 by plasma welding. One melting part 3 was formed in a spot shape. As shown in FIG. 1, the melting portion 3 is formed at one end portion of the electrode plate body 1 so as to cover the entire end surface of the laminate and the electrode lead in a state where the one end portion is melted.
(実施例2)
図6に示すように、電極板本体1の一端部において、電極板本体1の端面と、電極リード2の端面とをプラズマ溶接する際に、スポット状に2つの溶融部3を形成した以外は、実施例1と同様にして、電極板本体1と電極リード2とを接合させた。 (Example 2)
As shown in FIG. 6, when plasma welding the end surface of theelectrode plate body 1 and the end surface of the electrode lead 2 at one end portion of the electrode plate body 1, the two melted portions 3 are formed in a spot shape. In the same manner as in Example 1, the electrode plate body 1 and the electrode lead 2 were joined.
図6に示すように、電極板本体1の一端部において、電極板本体1の端面と、電極リード2の端面とをプラズマ溶接する際に、スポット状に2つの溶融部3を形成した以外は、実施例1と同様にして、電極板本体1と電極リード2とを接合させた。 (Example 2)
As shown in FIG. 6, when plasma welding the end surface of the
(比較例1)
図7に示すように、電極板本体1の一端部において、プラズマ溶接により、主に電極リード2を溶融させることにより、電極板本体1の端面と電極リード2の端面とを溶接して、溶融部3aを形成した以外は、実施例1と同様にして、電極板本体1と電極リード2とを接合させた。 (Comparative Example 1)
As shown in FIG. 7, at one end of the electrode platemain body 1, the electrode lead 2 is mainly melted by plasma welding to weld the end face of the electrode plate main body 1 and the end face of the electrode lead 2 to melt. The electrode plate body 1 and the electrode lead 2 were joined in the same manner as in Example 1 except that the portion 3a was formed.
図7に示すように、電極板本体1の一端部において、プラズマ溶接により、主に電極リード2を溶融させることにより、電極板本体1の端面と電極リード2の端面とを溶接して、溶融部3aを形成した以外は、実施例1と同様にして、電極板本体1と電極リード2とを接合させた。 (Comparative Example 1)
As shown in FIG. 7, at one end of the electrode plate
(比較例2)
図8に示すように、電極板本体1の一端部において、プラズマ溶接により、主に電極リード2を溶融させることにより、電極板本体1の端面と電極リード2の端面とを溶接して、溶融部3bを形成した以外は、実施例1と同様にして、電極板本体1と電極リード2とを接合させた。 (Comparative Example 2)
As shown in FIG. 8, at one end of theelectrode plate body 1, the end surface of the electrode plate body 1 and the end surface of the electrode lead 2 are welded by melting mainly the electrode lead 2 by plasma welding. The electrode plate body 1 and the electrode lead 2 were joined in the same manner as in Example 1 except that the portion 3b was formed.
図8に示すように、電極板本体1の一端部において、プラズマ溶接により、主に電極リード2を溶融させることにより、電極板本体1の端面と電極リード2の端面とを溶接して、溶融部3bを形成した以外は、実施例1と同様にして、電極板本体1と電極リード2とを接合させた。 (Comparative Example 2)
As shown in FIG. 8, at one end of the
(比較例3)
実施例1と同様に電極板本体1を作成した。 (Comparative Example 3)
Anelectrode plate body 1 was prepared in the same manner as in Example 1.
実施例1と同様に電極板本体1を作成した。 (Comparative Example 3)
An
(実施例3)
実施例1~2および比較例1~2で作製した電極板を、各実施例および比較例について、15個ずつ準備し、下記の評価を行った。 (Example 3)
Fifteen electrode plates prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were prepared for each Example and Comparative Example, and the following evaluation was performed.
実施例1~2および比較例1~2で作製した電極板を、各実施例および比較例について、15個ずつ準備し、下記の評価を行った。 (Example 3)
Fifteen electrode plates prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were prepared for each Example and Comparative Example, and the following evaluation was performed.
(1)溶融部の厚さおよび長さ
各例の50個の電極板のうち、5個について、電極板の積層体の厚さ方向における断面の電子顕微鏡写真を撮影し、積層体の厚さ方向における溶融部の厚さの平均値を求めた。
また、上記の断面の電子顕微鏡写真において、電極リードの長手方向における溶融部の長さの平均値を求めた。 (1) Thickness and length of melted part For five of the 50 electrode plates in each example, an electron micrograph of a cross section in the thickness direction of the laminate of the electrode plates was taken, and the thickness of the laminate The average value of the thickness of the melted part in the direction was determined.
Moreover, in the electron micrograph of the cross section, the average value of the length of the melted portion in the longitudinal direction of the electrode lead was determined.
各例の50個の電極板のうち、5個について、電極板の積層体の厚さ方向における断面の電子顕微鏡写真を撮影し、積層体の厚さ方向における溶融部の厚さの平均値を求めた。
また、上記の断面の電子顕微鏡写真において、電極リードの長手方向における溶融部の長さの平均値を求めた。 (1) Thickness and length of melted part For five of the 50 electrode plates in each example, an electron micrograph of a cross section in the thickness direction of the laminate of the electrode plates was taken, and the thickness of the laminate The average value of the thickness of the melted part in the direction was determined.
Moreover, in the electron micrograph of the cross section, the average value of the length of the melted portion in the longitudinal direction of the electrode lead was determined.
(2)引張強度および引張試験における破断状態
電極板本体と電極リードとの接合強度を下記の手順で評価した。
各例の50個の電極板のうち、5個について、溶融部における引張強度を測定した。具体的には、引張試験機に、電極板本体と、電極リードとを、それぞれ引っ張るように、電極板をセットし、一定の速度で、引張試験機の軸方向、具体的には電極板本体と電極リードとが互いに離れる方向に引っ張った。そして、溶接部分が破断したときの荷重(引張強度)を、接合強度として評価した。
また、引張試験において、破断した部分の状態を目視で観察した。 (2) Tensile strength and fracture state in tensile test The bonding strength between the electrode plate body and the electrode lead was evaluated by the following procedure.
Of the 50 electrode plates in each example, the tensile strength in the melted part was measured for 5 of them. Specifically, the electrode plate is set on the tensile tester so that the electrode plate main body and the electrode lead are pulled respectively, and at a constant speed, the axial direction of the tensile tester, specifically, the electrode plate main body And the electrode lead were pulled away from each other. And the load (tensile strength) when a welding part fractured | ruptured was evaluated as joining strength.
In the tensile test, the state of the fractured portion was visually observed.
電極板本体と電極リードとの接合強度を下記の手順で評価した。
各例の50個の電極板のうち、5個について、溶融部における引張強度を測定した。具体的には、引張試験機に、電極板本体と、電極リードとを、それぞれ引っ張るように、電極板をセットし、一定の速度で、引張試験機の軸方向、具体的には電極板本体と電極リードとが互いに離れる方向に引っ張った。そして、溶接部分が破断したときの荷重(引張強度)を、接合強度として評価した。
また、引張試験において、破断した部分の状態を目視で観察した。 (2) Tensile strength and fracture state in tensile test The bonding strength between the electrode plate body and the electrode lead was evaluated by the following procedure.
Of the 50 electrode plates in each example, the tensile strength in the melted part was measured for 5 of them. Specifically, the electrode plate is set on the tensile tester so that the electrode plate main body and the electrode lead are pulled respectively, and at a constant speed, the axial direction of the tensile tester, specifically, the electrode plate main body And the electrode lead were pulled away from each other. And the load (tensile strength) when a welding part fractured | ruptured was evaluated as joining strength.
In the tensile test, the state of the fractured portion was visually observed.
(3)捲回後のセパレータの状態
各例について、電極板5個を、それぞれ、セパレータとともに巻回し、溶融部の近傍におけるセパレータの破断や変形の有無を観察した。 (3) State of separator after winding For each example, five electrode plates were wound together with the separator, and the presence or absence of breakage or deformation of the separator in the vicinity of the melted portion was observed.
各例について、電極板5個を、それぞれ、セパレータとともに巻回し、溶融部の近傍におけるセパレータの破断や変形の有無を観察した。 (3) State of separator after winding For each example, five electrode plates were wound together with the separator, and the presence or absence of breakage or deformation of the separator in the vicinity of the melted portion was observed.
(4)溶融部の組成について
走査型電子顕微鏡(3Dリアルサーフェースビュー)にエネルギー分散型X線分析装置(商品名:Genesis XM2、EDAX社製)を装着し、溶融部の断面の銅およびケイ素の元素マップを調べた。 (4) About the composition of the fusion zone A scanning electron microscope (3D real surface view) is equipped with an energy dispersive X-ray analyzer (trade name: Genesis XM2, manufactured by EDAX), and copper and silicon in the cross section of the fusion zone The elemental map of was investigated.
走査型電子顕微鏡(3Dリアルサーフェースビュー)にエネルギー分散型X線分析装置(商品名:Genesis XM2、EDAX社製)を装着し、溶融部の断面の銅およびケイ素の元素マップを調べた。 (4) About the composition of the fusion zone A scanning electron microscope (3D real surface view) is equipped with an energy dispersive X-ray analyzer (trade name: Genesis XM2, manufactured by EDAX), and copper and silicon in the cross section of the fusion zone The elemental map of was investigated.
次に、溶融部の断面について、微小部X線回折装置(商品名:RINT2500、理学電機(株)製)を用いて、電極リードの長手方向において、溶融部の最端部から150μmで、溶融部の最上端部から100μm(溶融部の深さ100μm)の位置において、X線回折スペクトルを測定した。X線回折スペクトルに基づいて、溶融部に含まれる成分の定性分析を行った。
上記の評価結果を表1に示す。 Next, with respect to the cross section of the melted portion, it was melted at 150 μm from the extreme end of the melted portion in the longitudinal direction of the electrode lead using a microscopic X-ray diffractometer (trade name: RINT2500, manufactured by Rigaku Corporation). The X-ray diffraction spectrum was measured at aposition 100 μm from the uppermost end of the part (depth of the melted part 100 μm). Based on the X-ray diffraction spectrum, qualitative analysis of the components contained in the melted part was performed.
The evaluation results are shown in Table 1.
上記の評価結果を表1に示す。 Next, with respect to the cross section of the melted portion, it was melted at 150 μm from the extreme end of the melted portion in the longitudinal direction of the electrode lead using a microscopic X-ray diffractometer (trade name: RINT2500, manufactured by Rigaku Corporation). The X-ray diffraction spectrum was measured at a
The evaluation results are shown in Table 1.
表1に示されるように、実施例および比較例2では、積層体の厚さ方向における溶融部の厚さは、いずれも、積層体の厚さ200μm以上であった。一方、比較例1では、溶融部の厚さは、積層体の厚さよりも小さかった。
実施例では、いずれも0.5Nと高い引張強度が得られた。 As shown in Table 1, in Examples and Comparative Example 2, the thickness of the melted portion in the thickness direction of the laminated body was all 200 μm or more. On the other hand, in Comparative Example 1, the thickness of the melted part was smaller than the thickness of the laminate.
In Examples, a high tensile strength of 0.5 N was obtained in all cases.
実施例では、いずれも0.5Nと高い引張強度が得られた。 As shown in Table 1, in Examples and Comparative Example 2, the thickness of the melted portion in the thickness direction of the laminated body was all 200 μm or more. On the other hand, in Comparative Example 1, the thickness of the melted part was smaller than the thickness of the laminate.
In Examples, a high tensile strength of 0.5 N was obtained in all cases.
銅およびケイ素の元素マップから、実施例では、溶融部断面のほぼ全領域に、銅およびケイ素が存在していた。また、溶融部の所定の位置で銅とケイ素との元素モル比率を測定した結果、銅が90モル%、ケイ素が10モル%であった。これらの結果から、銅中にケイ素が拡散し、合金を形成していることが判った。
From the element map of copper and silicon, copper and silicon were present in almost all areas of the cross section of the melted part in the examples. Moreover, as a result of measuring the element molar ratio of copper and silicon at a predetermined position of the melted part, copper was 90 mol% and silicon was 10 mol%. From these results, it was found that silicon diffused in copper to form an alloy.
また、溶融部の断面についてのX線回折スペクトルによる分析結果から、実施例のいずれについても、溶融部では、銅のピークが、2θ=66°付近、2θ=78°付近および2θ=128°付近に確認された。また、2θ=68°付近および2θ=153°付近において、活物質と電極リードの金属成分との合金Cu5Siに由来するピークが確認された。なお、このようなCu5Siに由来するピークは、電極リード2の長手方向において、溶融部3の最端部から150μmで、いずれの深さの位置においても、確認された。従って、実施例においては、溶融部にCu5Si合金が含まれていることが判った。
Further, from the results of analysis by X-ray diffraction spectrum of the cross section of the melted portion, in all of the examples, the copper peaks in the melted portion are near 2θ = 66 °, 2θ = 78 ° and 2θ = 128 °. Was confirmed. In addition, in the vicinity of 2θ = 68 ° and 2θ = 153 °, peaks derived from the alloy Cu 5 Si of the active material and the metal component of the electrode lead were confirmed. Note that such a peak derived from Cu 5 Si was 150 μm from the extreme end of the melted portion 3 in the longitudinal direction of the electrode lead 2, and was confirmed at any depth position. Thus, in the embodiment, it was found that contain Cu 5 Si alloy to the molten portion.
以上の分析結果から、実施例の電極板では、溶融部に、銅と、Cu5Siを含む銅-ケイ素合金とが存在することが明らかとなった。そのため、活物質層を主に溶融することにより、電極板本体と電極リードとを溶接させた実施例では銅中にケイ素が多量に拡散して、溶融効率が増加して溶融部が拡大したものと推察される。
From the above analysis results, it has been clarified that in the electrode plate of the example, copper and a copper-silicon alloy containing Cu 5 Si exist in the molten part. Therefore, in the embodiment where the electrode plate body and the electrode lead were welded mainly by melting the active material layer, a large amount of silicon diffused in the copper, the melting efficiency increased, and the molten part expanded. It is guessed.
このように、実施例では、溶融部に電極板本体の構成成分と電極リードの金属成分との合金が形成されるとともに、溶融部の厚さが、積層体および電極リードの合計厚さ以上となっている。そのため、実施例のいずれにおいても、0.5Nと高い引張強度が得られたと考えられる。
As described above, in the embodiment, an alloy of the constituent component of the electrode plate body and the metal component of the electrode lead is formed in the melting portion, and the thickness of the melting portion is equal to or greater than the total thickness of the laminate and the electrode lead. It has become. Therefore, it is considered that a tensile strength as high as 0.5 N was obtained in any of the examples.
また、実施例では、引張試験による破断部分は、いずれも溶融部ではなく、集電体部分であった。このことからも、溶融部に含まれる合金が、引張強度に大きく影響していると考えられる。実施例の引張強度は、電極板本体自体の引張強度に依存しており、溶融部の引張強度は、電極板本体自体の引張強度よりも高い溶接強度を有していると推察できる。
Further, in the examples, the fractured part by the tensile test was not the melted part but the current collector part. From this also, it is considered that the alloy contained in the melted part has a great influence on the tensile strength. It can be inferred that the tensile strength of the example depends on the tensile strength of the electrode plate body itself, and the tensile strength of the melted portion has higher welding strength than the tensile strength of the electrode plate body itself.
一方、銅リードを主に溶融させて溶融部を形成した比較例1および2においては、溶融部のX線回折スペクトルの分析結果では、Cu5Siに由来するピークが確認されなかった。そのため、比較例1および2では、電極リードに含まれる銅と、活物質に含まれるケイ素との合金化が起こらず、溶融効率が低いことが分かる。
On the other hand, in Comparative Examples 1 and 2 in which the copper lead was mainly melted to form the melted portion, the peak derived from Cu 5 Si was not confirmed in the analysis result of the X-ray diffraction spectrum of the melted portion. Therefore, it can be seen that in Comparative Examples 1 and 2, alloying of copper contained in the electrode lead and silicon contained in the active material does not occur and the melting efficiency is low.
また、比較例1および2では、活物質は溶融せずに、活物質層の端面に、溶融部が付着した状態となるため、電極板本体と電極リードとの接合強度を高めることができない。しかも、電極板本体の一端部のかなり近くまで活物質層が存在するため、電極リードと集電体とを強固に溶接することが難しい。そのため、比較例2のように、溶融部の厚さを、積層体の厚さよりも大きくした場合であっても、溶接強度は、比較例1とそれほど大きく変わらない。
In Comparative Examples 1 and 2, the active material is not melted, and the melted portion is attached to the end face of the active material layer, so that the bonding strength between the electrode plate body and the electrode lead cannot be increased. In addition, since the active material layer exists very close to one end of the electrode plate body, it is difficult to firmly weld the electrode lead and the current collector. Therefore, even in the case where the thickness of the melted portion is larger than the thickness of the laminate as in Comparative Example 2, the welding strength is not so different from that in Comparative Example 1.
実施例において、溶融部に銅とケイ素との合金が形成される場合には、電極リードおよび活物質の溶融が促進され、溶融部はかなり肥大化する。これに対して、比較例1では、溶融部の大きさが電極板本体と電極リードの積層体の厚みよりも小さいため、銅とケイ素との合金化がほとんど進行しなかったと推察される。
In the embodiment, when an alloy of copper and silicon is formed in the melted portion, melting of the electrode lead and the active material is promoted, and the melted portion is considerably enlarged. On the other hand, in Comparative Example 1, since the size of the melted portion is smaller than the thickness of the laminated body of the electrode plate body and the electrode lead, it is surmised that the alloying of copper and silicon hardly progressed.
このように、比較例1および2では、銅とケイ素との合金化がほとんど進行せず、溶融部は、銅とケイ素との合金をほとんど含まない。そのため、これらの比較例では、引張強度が低く、実施例の値0.5Nよりも小さい荷重で破断した。また、これらの比較例では、集電体は破断されておらず、溶融部で破断されていることが確認された。
Thus, in Comparative Examples 1 and 2, the alloying of copper and silicon hardly proceeds, and the melted portion hardly contains an alloy of copper and silicon. Therefore, in these comparative examples, the tensile strength was low, and the sample was fractured with a load smaller than the value of 0.5 N in the example. In these comparative examples, it was confirmed that the current collector was not broken and was broken at the melted portion.
捲回後のセパレータの状態について、比較例2では、溶融部近傍において、セパレータが破断および変形していた。また、実施例1では、わずかに、溶融部近傍においてセパレータが破断、変形していたものの、実施例2では、セパレータの破断および変形は全く観察されなかった。
Regarding the state of the separator after winding, in Comparative Example 2, the separator was broken and deformed in the vicinity of the melted portion. Further, in Example 1, the separator was slightly broken and deformed in the vicinity of the melted portion, but in Example 2, no breakage and deformation of the separator were observed.
以上のことから、本発明の実施例に関して、従来例と比較して溶接強度の改善効果を確認することができた。特に、実施例2に関しては、高い溶接強度を有するとともに、セパレータの破断も確認できなかったことから、短絡抑制効果も高いと推察できる。
From the above, with respect to the examples of the present invention, it was possible to confirm the effect of improving the welding strength as compared with the conventional examples. In particular, regarding Example 2, since it has high welding strength and the separator was not confirmed to be broken, it can be presumed that the short-circuit suppressing effect is also high.
本発明を現時点での好ましい実施態様に関して説明したが、そのような開示を限定的に解釈してはならない。種々の変形および改変は、上記開示を読むことによって本発明に属する技術分野における当業者には間違いなく明らかになるであろう。したがって、添付の請求の範囲は、本発明の真の精神および範囲から逸脱することなく、すべての変形および改変を包含する、と解釈されるべきものである。
Although the present invention has been described in terms of the presently preferred embodiments, such disclosure should not be construed as limiting. Various changes and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains after reading the above disclosure. Accordingly, the appended claims should be construed to include all variations and modifications without departing from the true spirit and scope of this invention.
本発明の電気化学素子用電極板は、非水電解質二次電池などの各種電池の他、キャパシタなどの各種電気化学素子において、電極として使用するのに適している。そして、電気化学素子用電極板を含む電気化学素子は、大電流放電に適しており、例えば、高出力を必要とする電動工具や電気自動車などの駆動用電源、大容量のバックアップ用電源、蓄電用電源などに有用である。また、電気化学素子は、携帯電話、ノート型パーソナルコンピュータ、ビデオカムコーダなどの各種携帯型電子機器における駆動用電源、家庭用電力貯蔵装置における大型電源、などの用途に用いることもできる。
The electrode plate for an electrochemical element of the present invention is suitable for use as an electrode in various batteries such as a non-aqueous electrolyte secondary battery and various electrochemical elements such as a capacitor. An electrochemical element including an electrode plate for an electrochemical element is suitable for large current discharge, for example, a driving power source for a power tool or an electric vehicle that requires high output, a large-capacity backup power source, a power storage This is useful for power supplies. In addition, the electrochemical element can be used for applications such as a driving power source in various portable electronic devices such as a mobile phone, a notebook personal computer, and a video camcorder, and a large power source in a household power storage device.
1 電極板本体
1a 活物質層
1b 集電体
2 電極リード
3、3a、3b 溶融部
4、13 セパレータ
10 非水電解質二次電池
11 正極
11a 正極リード
12 負極
12b 負極リード
14 電極群
15a 上部絶縁板
15b 下部絶縁板
16 電池ケース
17 封口ガスケット
18 封口板 DESCRIPTION OFSYMBOLS 1 Electrode plate main body 1a Active material layer 1b Current collector 2 Electrode lead 3, 3a, 3b Melting part 4, 13 Separator 10 Nonaqueous electrolyte secondary battery 11 Positive electrode 11a Positive electrode lead 12 Negative electrode 12b Negative electrode lead 14 Electrode group 15a Upper insulating plate 15b Lower insulating plate 16 Battery case 17 Sealing gasket 18 Sealing plate
1a 活物質層
1b 集電体
2 電極リード
3、3a、3b 溶融部
4、13 セパレータ
10 非水電解質二次電池
11 正極
11a 正極リード
12 負極
12b 負極リード
14 電極群
15a 上部絶縁板
15b 下部絶縁板
16 電池ケース
17 封口ガスケット
18 封口板 DESCRIPTION OF
Claims (14)
- 金属を含む帯状の集電体と、前記集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体、
前記活物質層の一部の表面に配置された金属を含む電極リード、および
前記電極板本体の一端部において、前記電極板本体と、前記電極リードとを、電気的に接続する溶融部を具備し、
前記溶融部は、少なくとも前記活物質と、前記電極リードの金属成分との合金を含む、電気化学素子用電極板。 An electrode plate body comprising a laminate of a strip-shaped current collector containing metal and an active material layer formed on the surface of the current collector and containing an active material;
An electrode lead including a metal disposed on a part of the surface of the active material layer, and a melting portion that electrically connects the electrode plate body and the electrode lead at one end of the electrode plate body. And
The molten part is an electrode plate for an electrochemical element, containing at least an alloy of the active material and a metal component of the electrode lead. - 前記活物質が、ケイ素、ケイ素合金およびケイ素化合物からなる群より選択される少なくとも一種であり、
前記電極リードの前記金属成分が、銅または銅合金であり、
前記溶融部が、ケイ素と銅との合金を含む、請求項1記載の電気化学素子用電極板。 The active material is at least one selected from the group consisting of silicon, silicon alloys and silicon compounds;
The metal component of the electrode lead is copper or a copper alloy;
The electrode plate for an electrochemical element according to claim 1, wherein the molten part contains an alloy of silicon and copper. - 前記ケイ素と銅との合金が、Cu5Siを含む、請求項2記載の電気化学素子用電極板。 The electrode plate for an electrochemical element according to claim 2, wherein the alloy of silicon and copper contains Cu 5 Si.
- 前記溶融部の最端部から150μmのいずれの位置で前記溶融部のX線回折スペクトルを測定したときにも、2θ=68°付近に、前記ケイ素と銅との合金に由来するピークを有する、請求項2または3記載の電気化学素子用電極板。 When the X-ray diffraction spectrum of the melted part is measured at any position of 150 μm from the extreme end of the melted part, it has a peak derived from the alloy of silicon and copper in the vicinity of 2θ = 68 °. The electrode plate for electrochemical elements according to claim 2 or 3.
- 前記集電体の両方の表面に、前記活物質層が形成され、
前記溶融部が、前記集電体の両方の表面の前記活物質層の端面と前記電極リードとの溶融により形成される、請求項1~4のいずれか1項に記載の電気化学素子用電極板。 The active material layer is formed on both surfaces of the current collector,
The electrode for an electrochemical element according to any one of claims 1 to 4, wherein the melting part is formed by melting the end faces of the active material layer on both surfaces of the current collector and the electrode lead. Board. - 前記積層体の厚さ方向における前記溶融部の厚さが、前記積層体および前記電極リードの合計厚さ以上である、請求項1~5のいずれか1項に記載の電気化学素子用電極板。 The electrode plate for an electrochemical element according to any one of claims 1 to 5, wherein a thickness of the melted portion in a thickness direction of the laminate is equal to or greater than a total thickness of the laminate and the electrode lead. .
- 前記溶融部の長さが、300μm以上である、請求項1~6のいずれか1項に記載の電気化学素子用電極板。 The electrode plate for an electrochemical element according to any one of claims 1 to 6, wherein the melted portion has a length of 300 µm or more.
- 金属を含む帯状の集電体と、前記集電体の表面に形成され、かつ活物質を含む活物質層との積層体を含む電極板本体を準備する工程と、
前記活物質層の一部の表面に、前記電極板本体の一端部と、金属を含む電極リードの一端部とが近接するように、前記電極リードを配置する工程と、
前記電極板本体の一端部において、少なくとも前記活物質層の端面と、前記電極リードの端面とを溶接することにより、少なくとも前記活物質と、前記電極リードの金属成分との合金を含み、かつ前記電極板本体と、前記電極リードとを、電気的に接続する溶融部を形成する工程と、を具備する、電気化学素子用電極板の製造方法。 A step of preparing an electrode plate body including a laminate of a strip-shaped current collector containing a metal and an active material layer formed on the surface of the current collector and containing an active material;
Arranging the electrode lead so that one end of the electrode plate main body and one end of the electrode lead containing metal are close to a part of the surface of the active material layer;
At least one end surface of the active material layer and an end surface of the electrode lead are welded at one end of the electrode plate main body to include at least an alloy of the active material and the metal component of the electrode lead; and The manufacturing method of the electrode plate for electrochemical elements which comprises the process of forming the fusion | melting part which electrically connects an electrode plate main body and the said electrode lead. - 前記積層体の厚さ方向における前記溶融部の厚さを、前記積層体および前記電極リードの合計厚さ以上とする、請求項8記載の電気化学素子用電極板の製造方法。 The method for producing an electrode plate for an electrochemical element according to claim 8, wherein the thickness of the melted portion in the thickness direction of the laminate is equal to or greater than the total thickness of the laminate and the electrode lead.
- 前記活物質層の端面と前記電極リードの端面とが、プラズマ溶接により溶接される、請求項8または9記載の電気化学素子用電極板の製造方法。 The method for producing an electrode plate for an electrochemical element according to claim 8 or 9, wherein an end face of the active material layer and an end face of the electrode lead are welded by plasma welding.
- 前記溶接が、前記電極リードと前記集電体との間の前記活物質層を主に溶融させることにより行われる、請求項8~10のいずれか1項に記載の電気化学素子用電極板の製造方法。 The electrode plate for an electrochemical element according to any one of claims 8 to 10, wherein the welding is performed mainly by melting the active material layer between the electrode lead and the current collector. Production method.
- 第1電極としての、請求項1~7のいずれか1項に記載の電気化学素子用電極板と、
前記第1電極とは反対の極性の第2電極と、
前記第1電極と前記第2電極との間に介在するセパレータとを含む、電気化学素子。 The electrode plate for an electrochemical element according to any one of claims 1 to 7, as a first electrode,
A second electrode having a polarity opposite to that of the first electrode;
An electrochemical device comprising a separator interposed between the first electrode and the second electrode. - 前記第1電極と前記第2電極とを、前記セパレータを介して捲回または積層した電極群を含む、請求項12記載の電気化学素子。 The electrochemical element according to claim 12, comprising an electrode group obtained by winding or laminating the first electrode and the second electrode with the separator interposed therebetween.
- 前記溶融部の厚さが、前記第1電極および前記セパレータの合計厚さ以下である、請求項12または13記載の電気化学素子。 The electrochemical element according to claim 12 or 13, wherein a thickness of the melting part is equal to or less than a total thickness of the first electrode and the separator.
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JPH08138655A (en) * | 1994-11-11 | 1996-05-31 | Matsushita Electric Ind Co Ltd | Manufacture of electrode plate for battery |
JPH11111340A (en) * | 1997-09-30 | 1999-04-23 | Sanyo Electric Co Ltd | Lithium secondary battery |
JP2001256951A (en) * | 2000-03-10 | 2001-09-21 | Sanyo Electric Co Ltd | Nonaqueous electrolyte secondary battery |
JP2002289166A (en) * | 2001-03-27 | 2002-10-04 | Sanyo Electric Co Ltd | Manufacturing method of battery |
JP2010157484A (en) * | 2008-06-25 | 2010-07-15 | Panasonic Corp | Electrode structure for nonaqueous electrolyte secondary battery, its manufacturing method, and nonaqueous electrolyte secondary battery |
JP2011029026A (en) * | 2009-07-27 | 2011-02-10 | Panasonic Corp | Negative electrode, method of manufacturing the same, and nonaqueous electrolyte secondary battery |
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JPH08138655A (en) * | 1994-11-11 | 1996-05-31 | Matsushita Electric Ind Co Ltd | Manufacture of electrode plate for battery |
JPH11111340A (en) * | 1997-09-30 | 1999-04-23 | Sanyo Electric Co Ltd | Lithium secondary battery |
JP2001256951A (en) * | 2000-03-10 | 2001-09-21 | Sanyo Electric Co Ltd | Nonaqueous electrolyte secondary battery |
JP2002289166A (en) * | 2001-03-27 | 2002-10-04 | Sanyo Electric Co Ltd | Manufacturing method of battery |
JP2010157484A (en) * | 2008-06-25 | 2010-07-15 | Panasonic Corp | Electrode structure for nonaqueous electrolyte secondary battery, its manufacturing method, and nonaqueous electrolyte secondary battery |
JP2011029026A (en) * | 2009-07-27 | 2011-02-10 | Panasonic Corp | Negative electrode, method of manufacturing the same, and nonaqueous electrolyte secondary battery |
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