WO2012043119A1 - Nonaqueous electrolyte secondary battery - Google Patents
Nonaqueous electrolyte secondary battery Download PDFInfo
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- WO2012043119A1 WO2012043119A1 PCT/JP2011/069728 JP2011069728W WO2012043119A1 WO 2012043119 A1 WO2012043119 A1 WO 2012043119A1 JP 2011069728 W JP2011069728 W JP 2011069728W WO 2012043119 A1 WO2012043119 A1 WO 2012043119A1
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- surface area
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
- H01M50/434—Ceramics
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
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- 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
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- 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 a non-aqueous electrolyte secondary battery.
- Non-aqueous electrolyte secondary batteries represented by lithium-ion batteries are used in a wide variety of applications, including power supplies for portable devices, power supplies for electric tools and electric vehicles, power supplies for backups, and the like.
- a lithium transition metal oxide such as lithium cobaltate, lithium nickelate, or lithium manganate capable of reversibly occluding and releasing lithium ions is used as a positive electrode active material.
- the positive electrode active material is mixed with a binder, a conductive agent, and the like, applied on an aluminum foil as a positive electrode core, and used as a positive electrode plate.
- carbonaceous materials such as natural graphite, artificial graphite and coke are used as the negative electrode active material.
- a negative electrode active material is mixed with a binder etc., and it apply
- the positive electrode plate and the negative electrode plate are processed to a predetermined size to form an electrode body through a separator made of a resin microporous film such as polyethylene, and are housed and sealed together with the electrolyte.
- Such a non-aqueous electrolyte secondary battery has a high energy density, and thus various safety designs are made so as to ensure safety when using the battery.
- Patent Documents 1 and 2 disclose a method of forming a thin layered inorganic particle layer on the surface of a positive electrode plate or a negative electrode plate.
- the inorganic particles have heat resistance, and the inorganic particle layer made of these particles is not shrunk or damaged like a resin microporous separator even when the battery is heated to a high temperature. Therefore, even if the battery undergoes an internal short circuit and becomes high temperature, safety can be ensured and characteristics at high rate discharge can be improved.
- the inorganic particle layer does not contribute to the battery reaction and becomes a resistance to the battery reaction
- forming an inorganic particle layer on both the positive electrode and the negative electrode increases the resistance. It is formed on the surface of either the positive electrode or the negative electrode.
- the electrolytic solution contained in the outer package is not injected so as to fill an empty space other than the volume occupied by the electrode body, but is injected in an amount necessary for satisfying the design performance of the battery.
- the inorganic particle layer has a gap between the inorganic particles, and can absorb and hold the electrolyte in the gap.
- the inorganic particle layer absorbs a large amount of electrolyte, and the electrolytic mass distributed to the other electrode is reduced, so that the balance of the electrolytic mass is lost, especially the charge / discharge cycle characteristics deteriorate. It can happen that it becomes easier.
- the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a nonaqueous electrolyte secondary battery having improved charge / discharge cycle characteristics in a nonaqueous electrolyte secondary battery having an inorganic particle layer on the surface of one electrode.
- the next battery is to provide.
- a nonaqueous electrolyte secondary battery of the present invention is a nonaqueous electrolyte secondary battery including an electrode body in which a positive electrode and a negative electrode face each other with a separator interposed therebetween, and a nonaqueous electrolyte.
- the separator is provided with an inorganic particle layer made of inorganic material particles on the surface of one of the negative electrodes, and the separator has a surface area difference of 0.036 m 2 or more per 1 m 2 on one side and the other side, The small surface and the inorganic particle layer of one electrode are configured to face each other.
- the inorganic material constituting the inorganic particle layer can be an insulating metal oxide.
- the insulating metal oxide can be at least one selected from titanium oxide and aluminum oxide.
- the inorganic particle layer produced on the surface of one electrode can hold the electrolyte between the particles and can absorb even the electrolyte to be distributed to the other electrode.
- in the surface and the other surface has a difference of 1 m 2 per 0.036 m 2 or more surface area, are small surfaces whereas pole of the inorganic particle layer and the opposite surface area. That is, the surface having a large surface area faces the other electrode where the inorganic particle layer is not formed. Since the surface with a large surface area of the separator can hold more electrolyte than the surface with a small surface area, the one electrode with the inorganic particle layer faces the surface with the small surface area of the separator, and the other electrode without the inorganic particle layer and the surface area of the separator. When the surfaces having large currents face each other, the distribution balance between the electrolytic masses of both is improved, and a nonaqueous electrolyte secondary battery having good charge / discharge cycle characteristics is obtained.
- the inorganic particle layer is preferably an insulating inorganic oxide so that the safety of the battery can be ensured even when the battery is exposed to a high temperature and the insulation of the separator is broken, and titanium oxide or aluminum oxide, Or a mixture thereof.
- the thickness of the inorganic particle layer produced on one electrode is preferably 0.3 ⁇ m or more.
- the inorganic particle layer is resistant to battery reaction, and if it is too thick, the battery performance may be deteriorated, and it is preferably 3 ⁇ m or less.
- the average particle diameter of the insulating inorganic oxide is preferably from 0.05 to 0.7 ⁇ m because a homogeneous inorganic particle layer can be easily formed on the positive electrode or negative electrode surface. When the average particle size is larger than this range, the density of the inorganic particle layer becomes coarse, and the insulating property may be lowered. If the average particle size is smaller than this range, the electrolyte retention ability may be reduced.
- the difference in surface area between one surface and the other surface of the separator is too large, there is a possibility that distribution electrolyte balance collapses, it is preferable that 0.1 m 2 or less per 1 m 2.
- the surface area of the separator is preferably 1.09 to 1.15 m 2 per m 2 .
- the surface area of the separator is larger than this range, a part having an extremely thick separator and an extremely thin part are generated, and a possibility that a short circuit occurs in the thin part increases. If the surface area of the separator is smaller than this range, the above effects may be reduced even if there is a difference in surface area between the one surface and the other surface of the separator.
- FIG. 1A is a conceptual cross-sectional view showing a state of an electrode plate and a separator of a nonaqueous electrolyte secondary battery according to an example
- FIG. 1A is a partial schematic cross-sectional view of an electrode body of Example 1
- FIG. 1B is an electrode of Example 2
- It is a partial section conceptual diagram of a body.
- FIG. 2A is a conceptual cross-sectional view showing a state of an electrode plate and a separator of a nonaqueous electrolyte secondary battery according to a comparative example
- FIG. 2A is a partial sectional conceptual diagram of an electrode body of Comparative Example 1
- FIG. 2B is an electrode of Comparative Example 2 It is a partial section conceptual diagram of a body.
- FIG. 1 is a partial cross-sectional conceptual diagram showing the state of the electrode plate and separator of the nonaqueous electrolyte secondary battery according to the present invention.
- FIG. 2 is a partial cross-sectional conceptual diagram showing a state of an electrode plate and a separator of a nonaqueous electrolyte secondary battery according to a comparative example.
- an electrode body 12 in which a positive electrode plate and a negative electrode plate are wound in a spiral shape via a separator is housed in an outer can together with an electrolyte.
- the method for producing the non-aqueous electrolyte secondary battery is as follows.
- the slurry applied to the aluminum foil was heated and dried to produce a dry electrode plate having an active material layer formed on the aluminum foil.
- the dried electrode plate was compressed to 0.13 mm with a roller press and cut into a predetermined size to produce a positive electrode plate.
- a positive electrode plate that does not form an inorganic particle layer on the surface it is used in this state, and when a positive electrode plate that has an inorganic particle layer formed on the surface is used, it is inorganic by the method described below. What formed the particle layer was used.
- inorganic particles having an average particle diameter of 0.25 ⁇ m and a water-soluble acrylic rubber-based binder were mixed at a mass ratio of 50: 3.75, and the mixture was dispersed in water to prepare a slurry.
- the slurry was applied to the surface of the positive electrode plate prepared above by a doctor blade method and then dried to form a 2.5 ⁇ m inorganic particle layer.
- Graphite as a negative electrode active material, styrene butadiene rubber as a binder, and carboxymethyl cellulose as a viscosity modifier were mixed at a mass ratio of 96: 2: 2. This mixture was dispersed in water to prepare a slurry. This slurry was uniformly applied to both sides of a 10 ⁇ m thick copper foil by a doctor blade method. Then, the slurry apply
- ⁇ Preparation of inorganic particle layer on negative electrode plate surface Inorganic particles having an average particle diameter of 0.25 ⁇ m and polyvinylidene fluoride as a binder were mixed at a mass ratio of 30: 1, and the mixture was dispersed in NMP to prepare a slurry. This slurry was applied to the surface of the negative electrode plate prepared above by a doctor blade method and then dried to prepare a 2.5 ⁇ m inorganic particle layer.
- ⁇ Preparation of separator> A raw material polyethylene resin and a plasticizer were mixed and molded into a sheet while being heated and melted. Thereafter, the plasticizer was removed by extraction with a solvent and dried. The sheet was stretched to produce a separator having a thickness of 16 ⁇ m. By adjusting the stretching condition at this time, the surface area of one side is 1 m 2 per 1.125 m 2, while that of the other surface is 1.088m 2, 1m 2 per 0 to the surface area between the one surface and the other surface. A separator with a difference of 036 m 2 was obtained. The surface area of the separator was measured using a laser microscope (VK-9710 manufactured by Keyence).
- Attached software (VK Analyzer (version 2.0.0.4) was used for data analysis after the measurement.
- the positive electrode plate, the negative electrode plate, and the separator were wound into a cylindrical shape using a winder so that the positive electrode plate and the negative electrode plate were insulated by the separator, and an electrode body was produced.
- ⁇ Battery assembly> The electrode body and the electrolyte were inserted into a nickel-plated iron bottomed cylindrical outer can and sealed with a sealing body. In this manner, a cylindrical nonaqueous electrolyte secondary battery having a height of 65 mm and a diameter of 18 mm and a design capacity of 2700 mAh was produced.
- Example 1 As shown in FIG. 1A, an inorganic particle layer of titanium oxide is formed on the negative electrode, and the surface with a small surface area of the separator is opposed to the inorganic particle layer formed on the negative electrode, and a positive electrode that does not form an inorganic particle layer is used.
- a non-aqueous electrolyte secondary battery was produced as described above.
- Example 2 As shown in FIG. 1B, an inorganic particle layer of titanium oxide is formed on the positive electrode, the surface having a small surface area of the separator is opposed to the inorganic particle layer formed on the positive electrode, and a negative electrode that does not form an inorganic particle layer is used.
- a non-aqueous electrolyte secondary battery was produced as described above.
- Example 3 As shown in FIG. 1A, an inorganic particle layer of aluminum oxide having a thickness of 3.0 ⁇ m is formed on the negative electrode, and the surface of the separator having a small surface area is opposed to the inorganic particle layer formed on the negative electrode to form the inorganic particle layer.
- a non-aqueous electrolyte secondary battery was produced as described above using the positive electrode that was not used.
- an inorganic particle layer of titanium oxide is formed on the negative electrode so that the surface with the small surface area of the separator faces the positive electrode (that is, the surface with the small surface area of the separator does not face the inorganic particle layer)
- a non-aqueous electrolyte secondary battery was produced as described above using a positive electrode that did not form a particle layer.
- an inorganic particle layer of titanium oxide is formed on the positive electrode, and the surface having a small surface area of the separator is opposed to the negative electrode (that is, the surface having a small surface area of the separator is not opposed to the inorganic particle layer).
- a non-aqueous electrolyte secondary battery was produced as described above using a negative electrode that did not form a particle layer.
- Comparative Example 7 The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 1, except that used was a 1 m 2 per 0.013 m 2.
- Comparative Example 8 The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 2, except that used was a 1 m 2 per 0.013 m 2.
- Comparative Example 9 The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery as in Comparative Example 3 except for using those 1 m 2 per 0.013 m 2.
- Comparative Example 10 The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 4, except that used was a 1 m 2 per 0.013 m 2.
- Table 1 shows the test results of the above examples and comparative examples.
- Examples 1 to 3 and Comparative Examples 1 to 4 using a separator having a surface area difference of 0.036 m 2 an inorganic particle layer is formed on the electrode plate, and the inorganic particle layer faces the surface having a small surface area of the separator.
- Examples 1 to 3 in which are formed are Comparative Examples 1 and 2 in which the inorganic particle layer is not formed facing the surface of the separator having a small surface area, or Comparative Examples in which the inorganic particle layer is not formed on the electrode plate Compared with 3 and 4, the remaining capacity after the charge / discharge cycle exceeded 80%, which was good.
- the surface having the small surface area of the separator is arranged opposite to the side on which the inorganic particle layer is formed, that is, the surface having the large surface area of the separator has no inorganic particle layer. This is probably because the electrolyte was distributed in a well-balanced manner between the inorganic particle layer side and the surface of the separator having a large surface area.
- Comparative Examples 3 and 4 in which the inorganic particle layer was not formed on the electrode plate had slightly better characteristics than Comparative Examples 1 and 2, but were inferior to Examples 1 to 3. This is considered that the balance of electrolyte distribution is slightly better than those of Comparative Examples 1 and 2, but the electrolyte is biased to the surface of the separator having a large surface area.
- Example 1 Comparing Example 1 using titanium oxide for the inorganic particle layer and Example 3 using aluminum oxide, the charge / discharge cycle characteristics are almost the same and good. Therefore, an insulating metal oxide can be used for the material used for the inorganic particle layer.
- the wound electrode body is used.
- the same effect can be obtained by using a laminated electrode body.
- the mixed positive electrode active material of the hexagonal type lithium cobalt oxide which is a lithium transition metal complex oxide and a layered nickel manganese lithium cobalt oxide was used as the positive electrode
- the lithium cobalt oxide alone may be used as the positive electrode active material.
- Lithium acid oxide, lithium manganate, or the like may be used.
- the transition metal of the lithium transition metal composite oxide may be replaced with another element, or another element simple substance or compound may be added to the lithium transition metal composite oxide.
- graphite is used as the negative electrode active material, but other carbon materials such as coke can be used. Moreover, silicon, its oxide, an alloy type, and an oxide type negative electrode active material can also be used.
- the separator is made of polyethylene and has micropores.
- the separator may be made of polyolefin other than polyethylene such as polypropylene. It is also possible to use a resin microporous membrane other than polyolefin.
- a difference was made in the surface area of both surfaces by adjusting the production conditions such as stretching one film, but two or more microporous films were bonded together, A microporous membrane having a surface area difference between the one surface and the other surface can also be used. At this time, for example, two or more films having different properties, such as polyethylene and polypropylene, can be used together.
- a non-aqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics can be provided, so that industrial applicability is great.
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Abstract
[Problem] To provide a nonaqueous electrolyte secondary battery, which has excellent charge/discharge cycle characteristics, and wherein an inorganic particle layer is formed on an electrode plate.
[Solution] A nonaqueous electrolyte secondary battery which comprises a nonaqueous electrolyte and an electrode body that is obtained by arranging a positive electrode and a negative electrode so as to face each other with a separator interposed therebetween. The surface of one of the positive electrode and the negative electrode is provided with an inorganic particle layer that is composed of inorganic material particles. The separator has a surface area difference of 0.036 m2 or more per 1 m2 between one surface and the other surface, and the separator surface having the smaller surface area faces the inorganic particle layer of the one of the positive electrode and the negative electrode.
Description
本発明は非水電解質二次電池に関する。
The present invention relates to a non-aqueous electrolyte secondary battery.
リチウムイオン電池に代表される非水電解質二次電池は、携帯機器などの電源や、電動工具や電気自動車などの電源、バックアップ用電源など、多岐にわたり利用されている。
Non-aqueous electrolyte secondary batteries represented by lithium-ion batteries are used in a wide variety of applications, including power supplies for portable devices, power supplies for electric tools and electric vehicles, power supplies for backups, and the like.
このようなリチウムイオン電池は、正極活物質として、リチウムイオンを可逆的に吸蔵放出可能なコバルト酸リチウム、ニッケル酸リチウム、マンガン酸リチウムなど、リチウム遷移金属酸化物が用いられる。そして正極活物質は結着剤や導電剤等と混合され、正極芯体としてのアルミニウム箔上に塗布されて正極板として用いられる。
In such a lithium ion battery, a lithium transition metal oxide such as lithium cobaltate, lithium nickelate, or lithium manganate capable of reversibly occluding and releasing lithium ions is used as a positive electrode active material. The positive electrode active material is mixed with a binder, a conductive agent, and the like, applied on an aluminum foil as a positive electrode core, and used as a positive electrode plate.
一方、負極活物質としては、天然黒鉛、人造黒鉛、コークスなどの炭素質材料が用いられる。そして負極活物質は結着剤等と混合され、負極芯体としての銅箔上に塗布されて負極板として用いられる。
On the other hand, carbonaceous materials such as natural graphite, artificial graphite and coke are used as the negative electrode active material. And a negative electrode active material is mixed with a binder etc., and it apply | coated on the copper foil as a negative electrode core, and is used as a negative electrode plate.
正極板と負極板は所定の寸法に加工されて、ポリエチレンなどの樹脂製微多孔膜からなるセパレータを介して電極体をなし、電解質とともに外装体へ収納され封口される。
The positive electrode plate and the negative electrode plate are processed to a predetermined size to form an electrode body through a separator made of a resin microporous film such as polyethylene, and are housed and sealed together with the electrolyte.
このような非水電解質二次電池は、エネルギー密度が高いので、電池を利用する場面での安全性が確保できるように様々な安全設計がなされる。
Such a non-aqueous electrolyte secondary battery has a high energy density, and thus various safety designs are made so as to ensure safety when using the battery.
安全性を確保する設計のなかで、特許文献１、２では、正極板や負極板表面に薄い層状の無機粒子層を形成する方法が開示されている。
Among the designs for ensuring safety, Patent Documents 1 and 2 disclose a method of forming a thin layered inorganic particle layer on the surface of a positive electrode plate or a negative electrode plate.
これらの特許文献によると、無機粒子は耐熱性を有し、これらからなる無機粒子層は、電池が高温になっても樹脂製微多孔セパレータのように収縮や破損することがない。したがって、電池が内部短絡を起こして高温になっても、安全性が確保でき、高率放電での特性が改良できるとされる。
According to these patent documents, the inorganic particles have heat resistance, and the inorganic particle layer made of these particles is not shrunk or damaged like a resin microporous separator even when the battery is heated to a high temperature. Therefore, even if the battery undergoes an internal short circuit and becomes high temperature, safety can be ensured and characteristics at high rate discharge can be improved.
しかしながら、無機粒子層は、電池反応に寄与せず、電池反応にとって抵抗となることから、正極と負極の両方に無機粒子層を形成すると抵抗が増すので、電池性能を維持するには、通常は正極か負極のどちらかの表面に形成される。
However, since the inorganic particle layer does not contribute to the battery reaction and becomes a resistance to the battery reaction, forming an inorganic particle layer on both the positive electrode and the negative electrode increases the resistance. It is formed on the surface of either the positive electrode or the negative electrode.
ところで、外装体内に収められる電解液は、電極体の占める体積以外の空き空間を満たす様に注入するのではなく、その電池が備えるべき設計性能を満足するために必要な量だけ注入される。一方、無機粒子層は、無機粒子のそれぞれの粒子間に隙間を持ち、その隙間に電解質を吸収して保持することができる。一方極に無機粒子層を作製したとき、無機粒子層が多くの電解質を吸収して、他方極へ配分される電解質量が少なくなって電解質量
のバランスが崩れ、特に充放電サイクル特性が劣化しやすくなることが生じうる。 By the way, the electrolytic solution contained in the outer package is not injected so as to fill an empty space other than the volume occupied by the electrode body, but is injected in an amount necessary for satisfying the design performance of the battery. On the other hand, the inorganic particle layer has a gap between the inorganic particles, and can absorb and hold the electrolyte in the gap. When an inorganic particle layer is produced on one electrode, the inorganic particle layer absorbs a large amount of electrolyte, and the electrolytic mass distributed to the other electrode is reduced, so that the balance of the electrolytic mass is lost, especially the charge / discharge cycle characteristics deteriorate. It can happen that it becomes easier.
のバランスが崩れ、特に充放電サイクル特性が劣化しやすくなることが生じうる。 By the way, the electrolytic solution contained in the outer package is not injected so as to fill an empty space other than the volume occupied by the electrode body, but is injected in an amount necessary for satisfying the design performance of the battery. On the other hand, the inorganic particle layer has a gap between the inorganic particles, and can absorb and hold the electrolyte in the gap. When an inorganic particle layer is produced on one electrode, the inorganic particle layer absorbs a large amount of electrolyte, and the electrolytic mass distributed to the other electrode is reduced, so that the balance of the electrolytic mass is lost, especially the charge / discharge cycle characteristics deteriorate. It can happen that it becomes easier.
本発明は、上述の課題を解決するためになされたもので、その目的は、一方極の表面に無機粒子層を備える非水電解質二次電池において、充放電サイクル特性を改良した非水電解質二次電池を提供することにある。
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a nonaqueous electrolyte secondary battery having improved charge / discharge cycle characteristics in a nonaqueous electrolyte secondary battery having an inorganic particle layer on the surface of one electrode. The next battery is to provide.
上述の課題を解決するために、本発明の非水電解質二次電池は、正極と負極がセパレータを介して対向する電極体と、非水電解質を備える非水電解質二次電池であって、正極または負極のいずれか一方極の表面に無機材料粒子からなる無機粒子層を備え、セパレータは、一方面と他方面とで表面積の差が１ｍ２あたり０．０３６ｍ２以上であり、セパレータの表面積の小さい面と、一方極の無機粒子層とが対向するように構成する。
In order to solve the above-described problem, a nonaqueous electrolyte secondary battery of the present invention is a nonaqueous electrolyte secondary battery including an electrode body in which a positive electrode and a negative electrode face each other with a separator interposed therebetween, and a nonaqueous electrolyte. Alternatively, the separator is provided with an inorganic particle layer made of inorganic material particles on the surface of one of the negative electrodes, and the separator has a surface area difference of 0.036 m 2 or more per 1 m 2 on one side and the other side, The small surface and the inorganic particle layer of one electrode are configured to face each other.
また、本発明の非水電解質二次電池では、無機粒子層を構成する無機材料は、絶縁性の金属酸化物とすることができる。
In the nonaqueous electrolyte secondary battery of the present invention, the inorganic material constituting the inorganic particle layer can be an insulating metal oxide.
また、本発明の非水電解質二次電池では、絶縁性の金属酸化物は、酸化チタンと酸化アルミニウムから選択される少なくとも１種とすることができる。
In the nonaqueous electrolyte secondary battery of the present invention, the insulating metal oxide can be at least one selected from titanium oxide and aluminum oxide.
一方極の表面に作製された無機粒子層は、その粒子間に電解質を保持することができ、他方極に分配されるべき電解質までも吸収しうるが、本発明によれば、セパレータは、一方面と他方面とで１ｍ２あたり０．０３６ｍ２以上の表面積の差を有しており、表面積の小さい面が一方極の無機粒子層と対向している。すなわち、表面積が大きい面が無機粒子層の形成されてない他方極に対向している。セパレータの表面積の大きい面
は、表面積の小さい面よりも電解質を多く保持できるので、無機粒子層がある一方極とセパレータの表面積が小さい面が対向し、無機粒子層がない他方極とセパレータの表面積が大きい面が対向することで、両者の電解質量の分配バランスがよくなり、良好な充放電サイクル特性を持つ非水電解質二次電池が得られる。 The inorganic particle layer produced on the surface of one electrode can hold the electrolyte between the particles and can absorb even the electrolyte to be distributed to the other electrode. in the surface and the other surface has a difference of 1 m 2 per 0.036 m 2 or more surface area, are small surfaces whereas pole of the inorganic particle layer and the opposite surface area. That is, the surface having a large surface area faces the other electrode where the inorganic particle layer is not formed. Since the surface with a large surface area of the separator can hold more electrolyte than the surface with a small surface area, the one electrode with the inorganic particle layer faces the surface with the small surface area of the separator, and the other electrode without the inorganic particle layer and the surface area of the separator. When the surfaces having large currents face each other, the distribution balance between the electrolytic masses of both is improved, and a nonaqueous electrolyte secondary battery having good charge / discharge cycle characteristics is obtained.
は、表面積の小さい面よりも電解質を多く保持できるので、無機粒子層がある一方極とセパレータの表面積が小さい面が対向し、無機粒子層がない他方極とセパレータの表面積が大きい面が対向することで、両者の電解質量の分配バランスがよくなり、良好な充放電サイクル特性を持つ非水電解質二次電池が得られる。 The inorganic particle layer produced on the surface of one electrode can hold the electrolyte between the particles and can absorb even the electrolyte to be distributed to the other electrode. in the surface and the other surface has a difference of 1 m 2 per 0.036 m 2 or more surface area, are small surfaces whereas pole of the inorganic particle layer and the opposite surface area. That is, the surface having a large surface area faces the other electrode where the inorganic particle layer is not formed. Since the surface with a large surface area of the separator can hold more electrolyte than the surface with a small surface area, the one electrode with the inorganic particle layer faces the surface with the small surface area of the separator, and the other electrode without the inorganic particle layer and the surface area of the separator. When the surfaces having large currents face each other, the distribution balance between the electrolytic masses of both is improved, and a nonaqueous electrolyte secondary battery having good charge / discharge cycle characteristics is obtained.
このとき、電池が高温に曝されてセパレータの絶縁が破壊されても電池の安全性を確保できるように、無機粒子層は絶縁性の無機酸化物であることが好ましく、酸化チタンまたは酸化アルミニウム、またはそれらの混合物であることが好ましい。
At this time, the inorganic particle layer is preferably an insulating inorganic oxide so that the safety of the battery can be ensured even when the battery is exposed to a high temperature and the insulation of the separator is broken, and titanium oxide or aluminum oxide, Or a mixture thereof.
また、絶縁を保持するという理由から、一方極に作製される無機粒子層の厚さは０．３μｍ以上が好ましい。しかし無機粒子層は電池反応にとっては抵抗であり、あまり厚くすると電池性能を低下させるおそれがあり、３μｍ以下にすることが好ましい。さらに、絶縁性の無機酸化物の平均粒径は、０．０５～０．７μｍであると正極または負極表面へ均質の無機粒子層を形成しやすくなるので好ましい。平均粒径がこの範囲よりも大きくなると無機粒子層の密度が粗くなり、絶縁性が低下する可能性がある。平均粒径がこの範囲よりも小さくなると電解質の保持能力が低下する可能性がある。
Also, for the purpose of maintaining insulation, the thickness of the inorganic particle layer produced on one electrode is preferably 0.3 μm or more. However, the inorganic particle layer is resistant to battery reaction, and if it is too thick, the battery performance may be deteriorated, and it is preferably 3 μm or less. Further, the average particle diameter of the insulating inorganic oxide is preferably from 0.05 to 0.7 μm because a homogeneous inorganic particle layer can be easily formed on the positive electrode or negative electrode surface. When the average particle size is larger than this range, the density of the inorganic particle layer becomes coarse, and the insulating property may be lowered. If the average particle size is smaller than this range, the electrolyte retention ability may be reduced.
また、セパレータの一方面と他方面との表面積の差が大きすぎると、電解質の分配バランスが崩れるおそれがあるので、１ｍ２あたり０．１ｍ２以下であることが好ましい。さらに、セパレータの表面積は１ｍ２あたり１．０９～１．１５ｍ２であることが好ましい。セパレータの表面積がこの範囲より大きいとセパレータの厚さが極端に厚い部分と極端に薄い部分が生じ、薄い部分において短絡が生じる可能性が大きくなる。またセパレータの表面積がこの範囲より小さいと、セパレータの一方面と他方面とで表面積の差があっても、上記のような効果が小さくなることがある。
Also, the difference in surface area between one surface and the other surface of the separator is too large, there is a possibility that distribution electrolyte balance collapses, it is preferable that 0.1 m 2 or less per 1 m 2. Further, the surface area of the separator is preferably 1.09 to 1.15 m 2 per m 2 . When the surface area of the separator is larger than this range, a part having an extremely thick separator and an extremely thin part are generated, and a possibility that a short circuit occurs in the thin part increases. If the surface area of the separator is smaller than this range, the above effects may be reduced even if there is a difference in surface area between the one surface and the other surface of the separator.
本発明を実施するための形態を、図面に基づいて説明する。なお、本発明は下記の形態に限定されるものではなく、その要旨を変更しない範囲において適宜変更して実施することが可能である。
DETAILED DESCRIPTION Embodiments for carrying out the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following form, In the range which does not change the summary, it can change suitably and can implement.
なお、図１は本発明に係る非水電解質二次電池の極板とセパレータの状態を示す部分断面概念図である。図２は比較例に係る非水電解質二次電池の極板とセパレータの状態を示す部分断面概念図である。
FIG. 1 is a partial cross-sectional conceptual diagram showing the state of the electrode plate and separator of the nonaqueous electrolyte secondary battery according to the present invention. FIG. 2 is a partial cross-sectional conceptual diagram showing a state of an electrode plate and a separator of a nonaqueous electrolyte secondary battery according to a comparative example.
[実施の形態]
実施例の非水電解質二次電池は、正極板と負極板とがセパレータを介して渦巻き状に巻回した電極体１２が電解質と共に外装缶に収納されている。 [Embodiment]
In the nonaqueous electrolyte secondary battery of the example, an electrode body 12 in which a positive electrode plate and a negative electrode plate are wound in a spiral shape via a separator is housed in an outer can together with an electrolyte.
実施例の非水電解質二次電池は、正極板と負極板とがセパレータを介して渦巻き状に巻回した電極体１２が電解質と共に外装缶に収納されている。 [Embodiment]
In the nonaqueous electrolyte secondary battery of the example, an electrode body 12 in which a positive electrode plate and a negative electrode plate are wound in a spiral shape via a separator is housed in an outer can together with an electrolyte.
上記非水電解質二次電池の作製方法は以下のとおりである。
The method for producing the non-aqueous electrolyte secondary battery is as follows.
＜正極板の作製＞
コバルト酸リチウム（ＬｉＣｏ０．９７３Ｍｇ０．００５Ａｌ０．０２０Ｚｒ０．００２Ｏ２）と、層状ニッケルマンガンコバルト酸リチウム（ＬｉＭｎ０．３３Ｎｉ０．３３Ｃｏ０．３４Ｏ２）とを質量比で９：１の割合で混合した正極活物質と、導電剤してカーボンブラックと、結着剤としてポリフッ化ビニリデンとを、質量比９４：３：３で混合し
た。この混合物をＮ－メチル－２－ピロリドン（ＮＭＰ）に分散させて正極合剤スラリーを調製した。このスラリーをドクターブレード法により、厚さ１５μｍのアルミニウム箔の両面に均一に塗布した。アルミニウム箔に塗布したスラリーを加熱乾燥して、アルミニウム箔上に活物質層が形成された乾燥極板を作製した。乾燥極板をローラープレス機で０．１３ｍｍまで圧縮し、所定の寸法に裁断し、正極板を作製した。
後に説明する実施例、比較例において、表面に無機粒子層を形成しない正極板を用いるときはこの状態で用い、表面に無機粒子層を形成した正極板を用いるときは以下の説明する方法で無機粒子層を形成したものを用いた。 <Preparation of positive electrode plate>
Mass of lithium cobaltate (LiCo 0.973 Mg 0.005 Al 0.020 Zr 0.002 O 2 ) and layered lithium nickel manganese cobaltate (LiMn 0.33 Ni 0.33 Co 0.34 O 2 ) A positive electrode active material mixed at a ratio of 9: 1, carbon black as a conductive agent, and polyvinylidene fluoride as a binder were mixed at a mass ratio of 94: 3: 3. This mixture was dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode mixture slurry. This slurry was uniformly applied to both surfaces of an aluminum foil having a thickness of 15 μm by a doctor blade method. The slurry applied to the aluminum foil was heated and dried to produce a dry electrode plate having an active material layer formed on the aluminum foil. The dried electrode plate was compressed to 0.13 mm with a roller press and cut into a predetermined size to produce a positive electrode plate.
In Examples and Comparative Examples described later, when a positive electrode plate that does not form an inorganic particle layer on the surface is used, it is used in this state, and when a positive electrode plate that has an inorganic particle layer formed on the surface is used, it is inorganic by the method described below. What formed the particle layer was used.
コバルト酸リチウム（ＬｉＣｏ０．９７３Ｍｇ０．００５Ａｌ０．０２０Ｚｒ０．００２Ｏ２）と、層状ニッケルマンガンコバルト酸リチウム（ＬｉＭｎ０．３３Ｎｉ０．３３Ｃｏ０．３４Ｏ２）とを質量比で９：１の割合で混合した正極活物質と、導電剤してカーボンブラックと、結着剤としてポリフッ化ビニリデンとを、質量比９４：３：３で混合し
た。この混合物をＮ－メチル－２－ピロリドン（ＮＭＰ）に分散させて正極合剤スラリーを調製した。このスラリーをドクターブレード法により、厚さ１５μｍのアルミニウム箔の両面に均一に塗布した。アルミニウム箔に塗布したスラリーを加熱乾燥して、アルミニウム箔上に活物質層が形成された乾燥極板を作製した。乾燥極板をローラープレス機で０．１３ｍｍまで圧縮し、所定の寸法に裁断し、正極板を作製した。
後に説明する実施例、比較例において、表面に無機粒子層を形成しない正極板を用いるときはこの状態で用い、表面に無機粒子層を形成した正極板を用いるときは以下の説明する方法で無機粒子層を形成したものを用いた。 <Preparation of positive electrode plate>
Mass of lithium cobaltate (LiCo 0.973 Mg 0.005 Al 0.020 Zr 0.002 O 2 ) and layered lithium nickel manganese cobaltate (LiMn 0.33 Ni 0.33 Co 0.34 O 2 ) A positive electrode active material mixed at a ratio of 9: 1, carbon black as a conductive agent, and polyvinylidene fluoride as a binder were mixed at a mass ratio of 94: 3: 3. This mixture was dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode mixture slurry. This slurry was uniformly applied to both surfaces of an aluminum foil having a thickness of 15 μm by a doctor blade method. The slurry applied to the aluminum foil was heated and dried to produce a dry electrode plate having an active material layer formed on the aluminum foil. The dried electrode plate was compressed to 0.13 mm with a roller press and cut into a predetermined size to produce a positive electrode plate.
In Examples and Comparative Examples described later, when a positive electrode plate that does not form an inorganic particle layer on the surface is used, it is used in this state, and when a positive electrode plate that has an inorganic particle layer formed on the surface is used, it is inorganic by the method described below. What formed the particle layer was used.
＜正極板表面への無機粒子層の形成＞
平均粒径０．２５μｍの無機粒子と水溶性アクリルゴム系の結着剤を質量比５０：３．７５の割合で混合し、この混合物を水に分散させてスラリーを調製した。このスラリーを上記で作製した正極板表面にドクターブレード法により塗布後に乾燥させて２．５μｍの無機粒子層を形成した。 <Formation of inorganic particle layer on positive electrode plate surface>
Inorganic particles having an average particle diameter of 0.25 μm and a water-soluble acrylic rubber-based binder were mixed at a mass ratio of 50: 3.75, and the mixture was dispersed in water to prepare a slurry. The slurry was applied to the surface of the positive electrode plate prepared above by a doctor blade method and then dried to form a 2.5 μm inorganic particle layer.
平均粒径０．２５μｍの無機粒子と水溶性アクリルゴム系の結着剤を質量比５０：３．７５の割合で混合し、この混合物を水に分散させてスラリーを調製した。このスラリーを上記で作製した正極板表面にドクターブレード法により塗布後に乾燥させて２．５μｍの無機粒子層を形成した。 <Formation of inorganic particle layer on positive electrode plate surface>
Inorganic particles having an average particle diameter of 0.25 μm and a water-soluble acrylic rubber-based binder were mixed at a mass ratio of 50: 3.75, and the mixture was dispersed in water to prepare a slurry. The slurry was applied to the surface of the positive electrode plate prepared above by a doctor blade method and then dried to form a 2.5 μm inorganic particle layer.
＜負極板の作製＞
負極活物質として黒鉛と、結着剤としてスチレンブタジエンゴムと、粘度調整剤としてカルボキシメチルセルロースとを、質量比で９６：２：２となるように混合した。この混合物を水に分散してスラリーを調製した。このスラリーをドクターブレード法により、厚さ１０μｍの銅箔の両面に均一に塗布した。その後、銅箔に塗布したスラリーを加熱乾燥して、銅箔上に活物質層が形成された乾燥極板を作製した。乾燥極板をローラープレス機
で厚さ０．１２ｍｍまで圧縮し、所定の寸法に裁断して負極板を作製した。
後に説明する実施例、比較例において、表面に無機粒子層を形成しない負極板を用いるときはこの状態で用い、表面に無機粒子層を形成した負極板を用いるときは以下の説明する方法で無機粒子層を形成したものを用いた。
<Preparation of negative electrode plate>
Graphite as a negative electrode active material, styrene butadiene rubber as a binder, and carboxymethyl cellulose as a viscosity modifier were mixed at a mass ratio of 96: 2: 2. This mixture was dispersed in water to prepare a slurry. This slurry was uniformly applied to both sides of a 10 μm thick copper foil by a doctor blade method. Then, the slurry apply | coated to copper foil was heat-dried, and the dry electrode plate with which the active material layer was formed on copper foil was produced. The dried electrode plate was compressed to a thickness of 0.12 mm with a roller press and cut into a predetermined size to produce a negative electrode plate.
In Examples and Comparative Examples to be described later, when using a negative electrode plate that does not form an inorganic particle layer on the surface, it is used in this state, and when using a negative electrode plate that has an inorganic particle layer formed on the surface, it is inorganic by the method described below. What formed the particle layer was used.
負極活物質として黒鉛と、結着剤としてスチレンブタジエンゴムと、粘度調整剤としてカルボキシメチルセルロースとを、質量比で９６：２：２となるように混合した。この混合物を水に分散してスラリーを調製した。このスラリーをドクターブレード法により、厚さ１０μｍの銅箔の両面に均一に塗布した。その後、銅箔に塗布したスラリーを加熱乾燥して、銅箔上に活物質層が形成された乾燥極板を作製した。乾燥極板をローラープレス機
で厚さ０．１２ｍｍまで圧縮し、所定の寸法に裁断して負極板を作製した。
後に説明する実施例、比較例において、表面に無機粒子層を形成しない負極板を用いるときはこの状態で用い、表面に無機粒子層を形成した負極板を用いるときは以下の説明する方法で無機粒子層を形成したものを用いた。
<Preparation of negative electrode plate>
Graphite as a negative electrode active material, styrene butadiene rubber as a binder, and carboxymethyl cellulose as a viscosity modifier were mixed at a mass ratio of 96: 2: 2. This mixture was dispersed in water to prepare a slurry. This slurry was uniformly applied to both sides of a 10 μm thick copper foil by a doctor blade method. Then, the slurry apply | coated to copper foil was heat-dried, and the dry electrode plate with which the active material layer was formed on copper foil was produced. The dried electrode plate was compressed to a thickness of 0.12 mm with a roller press and cut into a predetermined size to produce a negative electrode plate.
In Examples and Comparative Examples to be described later, when using a negative electrode plate that does not form an inorganic particle layer on the surface, it is used in this state, and when using a negative electrode plate that has an inorganic particle layer formed on the surface, it is inorganic by the method described below. What formed the particle layer was used.
＜負極板表面への無機粒子層の作製＞
平均粒径０．２５μｍの無機粒子と結着剤としてポリフッ化ビニリデンとを質量比３０：１の割合で混合し、この混合物をＮＭＰに分散させてスラリーを調製した。このスラリーを上記で作製した負極板表面にドクターブレード法により塗布後に乾燥させて２．５μｍの無機粒子層を作製した。 <Preparation of inorganic particle layer on negative electrode plate surface>
Inorganic particles having an average particle diameter of 0.25 μm and polyvinylidene fluoride as a binder were mixed at a mass ratio of 30: 1, and the mixture was dispersed in NMP to prepare a slurry. This slurry was applied to the surface of the negative electrode plate prepared above by a doctor blade method and then dried to prepare a 2.5 μm inorganic particle layer.
平均粒径０．２５μｍの無機粒子と結着剤としてポリフッ化ビニリデンとを質量比３０：１の割合で混合し、この混合物をＮＭＰに分散させてスラリーを調製した。このスラリーを上記で作製した負極板表面にドクターブレード法により塗布後に乾燥させて２．５μｍの無機粒子層を作製した。 <Preparation of inorganic particle layer on negative electrode plate surface>
Inorganic particles having an average particle diameter of 0.25 μm and polyvinylidene fluoride as a binder were mixed at a mass ratio of 30: 1, and the mixture was dispersed in NMP to prepare a slurry. This slurry was applied to the surface of the negative electrode plate prepared above by a doctor blade method and then dried to prepare a 2.5 μm inorganic particle layer.
＜セパレータの作製＞
原料のポリエチレン樹脂と可塑剤とを混合し、加熱溶融しながらシート状に成形した。その後、溶媒で可塑剤を抽出除去して乾燥させた。そしてこのシートを延伸して厚さ１６μｍのセパレータを作製した。このとき延伸具合を調整することで、一方面の表面積は１ｍ２あたり１．１２５ｍ２であり、他方面のそれは１．０８８ｍ２であり、一方面と他方面とで表面積に１ｍ２あたり０．０３６ｍ２の差があるセパレータを得た。なおセパレータの表面積は、レーザー顕微鏡（キーエンス製ＶＫ－９７１０）を用いて測定した。測定後のデータ解析には、付属ソフト（ＶＫ Ａｎａｌｙｚｅｒ（バージョン2.0.0.4））を用いた。レーザー顕微鏡のレーザー波長は、４０８ｎｍの単波長光と白色光とを用いた。これらの光はいずれも可視光線であり、理論的にその分解能は１００～２００ｎｍ程度となる。セパレータの孔（リチウムイオン伝導用の孔）は、平均孔径が５０ｎｍであるため、表面積測定ではセパレータの孔の影響はないものと考えられる。 <Preparation of separator>
A raw material polyethylene resin and a plasticizer were mixed and molded into a sheet while being heated and melted. Thereafter, the plasticizer was removed by extraction with a solvent and dried. The sheet was stretched to produce a separator having a thickness of 16 μm. By adjusting the stretching condition at this time, the surface area of one side is 1 m 2 per 1.125 m 2, while that of the other surface is 1.088m 2, 1m 2 per 0 to the surface area between the one surface and the other surface. A separator with a difference of 036 m 2 was obtained. The surface area of the separator was measured using a laser microscope (VK-9710 manufactured by Keyence). Attached software (VK Analyzer (version 2.0.0.4)) was used for data analysis after the measurement. As the laser wavelength of the laser microscope, single wavelength light of 408 nm and white light were used. These lights are all visible light, and theoretically the resolution is about 100 to 200 nm. Since the pores of the separator (holes for lithium ion conduction) have an average pore diameter of 50 nm, it is considered that there is no influence of the pores of the separator in the surface area measurement.
原料のポリエチレン樹脂と可塑剤とを混合し、加熱溶融しながらシート状に成形した。その後、溶媒で可塑剤を抽出除去して乾燥させた。そしてこのシートを延伸して厚さ１６μｍのセパレータを作製した。このとき延伸具合を調整することで、一方面の表面積は１ｍ２あたり１．１２５ｍ２であり、他方面のそれは１．０８８ｍ２であり、一方面と他方面とで表面積に１ｍ２あたり０．０３６ｍ２の差があるセパレータを得た。なおセパレータの表面積は、レーザー顕微鏡（キーエンス製ＶＫ－９７１０）を用いて測定した。測定後のデータ解析には、付属ソフト（ＶＫ Ａｎａｌｙｚｅｒ（バージョン2.0.0.4））を用いた。レーザー顕微鏡のレーザー波長は、４０８ｎｍの単波長光と白色光とを用いた。これらの光はいずれも可視光線であり、理論的にその分解能は１００～２００ｎｍ程度となる。セパレータの孔（リチウムイオン伝導用の孔）は、平均孔径が５０ｎｍであるため、表面積測定ではセパレータの孔の影響はないものと考えられる。 <Preparation of separator>
A raw material polyethylene resin and a plasticizer were mixed and molded into a sheet while being heated and melted. Thereafter, the plasticizer was removed by extraction with a solvent and dried. The sheet was stretched to produce a separator having a thickness of 16 μm. By adjusting the stretching condition at this time, the surface area of one side is 1 m 2 per 1.125 m 2, while that of the other surface is 1.088m 2, 1m 2 per 0 to the surface area between the one surface and the other surface. A separator with a difference of 036 m 2 was obtained. The surface area of the separator was measured using a laser microscope (VK-9710 manufactured by Keyence). Attached software (VK Analyzer (version 2.0.0.4)) was used for data analysis after the measurement. As the laser wavelength of the laser microscope, single wavelength light of 408 nm and white light were used. These lights are all visible light, and theoretically the resolution is about 100 to 200 nm. Since the pores of the separator (holes for lithium ion conduction) have an average pore diameter of 50 nm, it is considered that there is no influence of the pores of the separator in the surface area measurement.
＜電極体の作製＞
上記正極板と負極板とセパレータとを、正極板と負極板がセパレータにより絶縁されるように、巻き取り機を用いて円筒状に巻回して電極体を作製した。 <Production of electrode body>
The positive electrode plate, the negative electrode plate, and the separator were wound into a cylindrical shape using a winder so that the positive electrode plate and the negative electrode plate were insulated by the separator, and an electrode body was produced.
上記正極板と負極板とセパレータとを、正極板と負極板がセパレータにより絶縁されるように、巻き取り機を用いて円筒状に巻回して電極体を作製した。 <Production of electrode body>
The positive electrode plate, the negative electrode plate, and the separator were wound into a cylindrical shape using a winder so that the positive electrode plate and the negative electrode plate were insulated by the separator, and an electrode body was produced.
＜電解質の調製＞
エチレンカーボネートとエチルメチルカーボネートを体積比で３０：７０（２５℃、１気圧）の割合で混合した非水溶媒に、ビニレンカーボネートを１質量％と電解質塩として六フッ化リン酸リチウムを１．２モル／リットル溶解した。 <Preparation of electrolyte>
In a non-aqueous solvent in which ethylene carbonate and ethyl methyl carbonate are mixed at a volume ratio of 30:70 (25 ° C., 1 atm), 1% by mass of vinylene carbonate and electrolyte salt as a lithium hexafluorophosphate 1.2% Mol / liter dissolved.
エチレンカーボネートとエチルメチルカーボネートを体積比で３０：７０（２５℃、１気圧）の割合で混合した非水溶媒に、ビニレンカーボネートを１質量％と電解質塩として六フッ化リン酸リチウムを１．２モル／リットル溶解した。 <Preparation of electrolyte>
In a non-aqueous solvent in which ethylene carbonate and ethyl methyl carbonate are mixed at a volume ratio of 30:70 (25 ° C., 1 atm), 1% by mass of vinylene carbonate and electrolyte salt as a lithium hexafluorophosphate 1.2% Mol / liter dissolved.
＜電池の組み立て＞
電極体と電解質とをニッケルメッキした鉄製の有底円筒形の外装缶に挿入し、封口体にて密封した。このようにして、高さ６５ｍｍ、直径１８ｍｍで、設計容量２７００ｍＡｈの円筒形非水電解質二次電池を作製した。 <Battery assembly>
The electrode body and the electrolyte were inserted into a nickel-plated iron bottomed cylindrical outer can and sealed with a sealing body. In this manner, a cylindrical nonaqueous electrolyte secondary battery having a height of 65 mm and a diameter of 18 mm and a design capacity of 2700 mAh was produced.
電極体と電解質とをニッケルメッキした鉄製の有底円筒形の外装缶に挿入し、封口体にて密封した。このようにして、高さ６５ｍｍ、直径１８ｍｍで、設計容量２７００ｍＡｈの円筒形非水電解質二次電池を作製した。 <Battery assembly>
The electrode body and the electrolyte were inserted into a nickel-plated iron bottomed cylindrical outer can and sealed with a sealing body. In this manner, a cylindrical nonaqueous electrolyte secondary battery having a height of 65 mm and a diameter of 18 mm and a design capacity of 2700 mAh was produced.
（実施例１）
図１Ａのように負極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が、負極に形成された無機粒子層と対向するようにし、無機粒子層を形成しない正極を用いて、上記のように非水電解質二次電池を作製した。 Example 1
As shown in FIG. 1A, an inorganic particle layer of titanium oxide is formed on the negative electrode, and the surface with a small surface area of the separator is opposed to the inorganic particle layer formed on the negative electrode, and a positive electrode that does not form an inorganic particle layer is used. A non-aqueous electrolyte secondary battery was produced as described above.
図１Ａのように負極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が、負極に形成された無機粒子層と対向するようにし、無機粒子層を形成しない正極を用いて、上記のように非水電解質二次電池を作製した。 Example 1
As shown in FIG. 1A, an inorganic particle layer of titanium oxide is formed on the negative electrode, and the surface with a small surface area of the separator is opposed to the inorganic particle layer formed on the negative electrode, and a positive electrode that does not form an inorganic particle layer is used. A non-aqueous electrolyte secondary battery was produced as described above.
（実施例２）
図１Ｂのように正極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が、正極に形成された無機粒子層と対向するようにし、無機粒子層を形成しない負極を用いて、上記のように非水電解質二次電池を作製した。 (Example 2)
As shown in FIG. 1B, an inorganic particle layer of titanium oxide is formed on the positive electrode, the surface having a small surface area of the separator is opposed to the inorganic particle layer formed on the positive electrode, and a negative electrode that does not form an inorganic particle layer is used. A non-aqueous electrolyte secondary battery was produced as described above.
図１Ｂのように正極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が、正極に形成された無機粒子層と対向するようにし、無機粒子層を形成しない負極を用いて、上記のように非水電解質二次電池を作製した。 (Example 2)
As shown in FIG. 1B, an inorganic particle layer of titanium oxide is formed on the positive electrode, the surface having a small surface area of the separator is opposed to the inorganic particle layer formed on the positive electrode, and a negative electrode that does not form an inorganic particle layer is used. A non-aqueous electrolyte secondary battery was produced as described above.
（実施例３）
図１Ａのように負極に厚さ３．０μｍの酸化アルミニウムの無機粒子層を形成し、セパレータの表面積の小さい面が、負極に形成された無機粒子層と対向するようにし、無機粒子層を形成しない正極を用いて、上記のように非水電解質二次電池を作製した。 (Example 3)
As shown in FIG. 1A, an inorganic particle layer of aluminum oxide having a thickness of 3.0 μm is formed on the negative electrode, and the surface of the separator having a small surface area is opposed to the inorganic particle layer formed on the negative electrode to form the inorganic particle layer. A non-aqueous electrolyte secondary battery was produced as described above using the positive electrode that was not used.
図１Ａのように負極に厚さ３．０μｍの酸化アルミニウムの無機粒子層を形成し、セパレータの表面積の小さい面が、負極に形成された無機粒子層と対向するようにし、無機粒子層を形成しない正極を用いて、上記のように非水電解質二次電池を作製した。 (Example 3)
As shown in FIG. 1A, an inorganic particle layer of aluminum oxide having a thickness of 3.0 μm is formed on the negative electrode, and the surface of the separator having a small surface area is opposed to the inorganic particle layer formed on the negative electrode to form the inorganic particle layer. A non-aqueous electrolyte secondary battery was produced as described above using the positive electrode that was not used.
（比較例１）
図２Ａのように負極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が正極に対向するよう（すなわち、セパレータの表面積の小さい面と無機粒子層が対向しない状態）にし、無機粒子層を形成しない正極を用いて、上記のように非水電解質二次電池を作製した。 (Comparative Example 1)
As shown in FIG. 2A, an inorganic particle layer of titanium oxide is formed on the negative electrode so that the surface with the small surface area of the separator faces the positive electrode (that is, the surface with the small surface area of the separator does not face the inorganic particle layer) A non-aqueous electrolyte secondary battery was produced as described above using a positive electrode that did not form a particle layer.
図２Ａのように負極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が正極に対向するよう（すなわち、セパレータの表面積の小さい面と無機粒子層が対向しない状態）にし、無機粒子層を形成しない正極を用いて、上記のように非水電解質二次電池を作製した。 (Comparative Example 1)
As shown in FIG. 2A, an inorganic particle layer of titanium oxide is formed on the negative electrode so that the surface with the small surface area of the separator faces the positive electrode (that is, the surface with the small surface area of the separator does not face the inorganic particle layer) A non-aqueous electrolyte secondary battery was produced as described above using a positive electrode that did not form a particle layer.
（比較例２）
図２Ｂのように正極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が負極に対向するよう（すなわち、セパレータの表面積の小さい面と無機粒子層が対向しない状態）にし、無機粒子層を形成しない負極を用いて、上記のように非水電解質二次電池を作製した。 (Comparative Example 2)
As shown in FIG. 2B, an inorganic particle layer of titanium oxide is formed on the positive electrode, and the surface having a small surface area of the separator is opposed to the negative electrode (that is, the surface having a small surface area of the separator is not opposed to the inorganic particle layer). A non-aqueous electrolyte secondary battery was produced as described above using a negative electrode that did not form a particle layer.
図２Ｂのように正極に酸化チタンの無機粒子層を形成し、セパレータの表面積の小さい面が負極に対向するよう（すなわち、セパレータの表面積の小さい面と無機粒子層が対向しない状態）にし、無機粒子層を形成しない負極を用いて、上記のように非水電解質二次電池を作製した。 (Comparative Example 2)
As shown in FIG. 2B, an inorganic particle layer of titanium oxide is formed on the positive electrode, and the surface having a small surface area of the separator is opposed to the negative electrode (that is, the surface having a small surface area of the separator is not opposed to the inorganic particle layer). A non-aqueous electrolyte secondary battery was produced as described above using a negative electrode that did not form a particle layer.
（比較例３）
どちらの極板表面にも無機粒子層を形成せず、セパレータの表面積の小さい面が負極に対向するようにして、上記のように非水電解質二次電池を作製した。 (Comparative Example 3)
The inorganic particle layer was not formed on either electrode plate surface, and the non-aqueous electrolyte secondary battery was produced as described above with the separator having a small surface area facing the negative electrode.
どちらの極板表面にも無機粒子層を形成せず、セパレータの表面積の小さい面が負極に対向するようにして、上記のように非水電解質二次電池を作製した。 (Comparative Example 3)
The inorganic particle layer was not formed on either electrode plate surface, and the non-aqueous electrolyte secondary battery was produced as described above with the separator having a small surface area facing the negative electrode.
（比較例４）
どちらの極板表面にも無機粒子層を形成せず、セパレータの表面積の小さい面が正極に対向するようにして、上記のように非水電解質二次電池を作製した。 (Comparative Example 4)
The inorganic particle layer was not formed on either electrode plate surface, and the non-aqueous electrolyte secondary battery was produced as described above with the separator having a small surface area facing the positive electrode.
どちらの極板表面にも無機粒子層を形成せず、セパレータの表面積の小さい面が正極に対向するようにして、上記のように非水電解質二次電池を作製した。 (Comparative Example 4)
The inorganic particle layer was not formed on either electrode plate surface, and the non-aqueous electrolyte secondary battery was produced as described above with the separator having a small surface area facing the positive electrode.
（比較例５）
セパレータの一方面の表面積が１ｍ２あたり１．０４０ｍ２で、他方面のそれが１．０２７ｍ２であり、表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は実施例１と同様の非水電解質二次電池を作製した。 (Comparative Example 5)
In one side of the surface area of 1 m 2 per 1.040M 2 of the separator, the other surface it is 1.027M 2, except that the difference in surface area was used in 1 m 2 per 0.013 m 2 from Example 1 A similar nonaqueous electrolyte secondary battery was produced.
セパレータの一方面の表面積が１ｍ２あたり１．０４０ｍ２で、他方面のそれが１．０２７ｍ２であり、表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は実施例１と同様の非水電解質二次電池を作製した。 (Comparative Example 5)
In one side of the surface area of 1 m 2 per 1.040M 2 of the separator, the other surface it is 1.027M 2, except that the difference in surface area was used in 1 m 2 per 0.013 m 2 from Example 1 A similar nonaqueous electrolyte secondary battery was produced.
（比較例６）
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は実施例２と同様の非水電解質二次電池を作製した。 (Comparative Example 6)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery as in Example 2 except for using those 1 m 2 per 0.013 m 2.
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は実施例２と同様の非水電解質二次電池を作製した。 (Comparative Example 6)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery as in Example 2 except for using those 1 m 2 per 0.013 m 2.
（比較例７）
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例１と同様の非水電解質二次電池を作製した。 (Comparative Example 7)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 1, except that used was a 1 m 2 per 0.013 m 2.
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例１と同様の非水電解質二次電池を作製した。 (Comparative Example 7)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 1, except that used was a 1 m 2 per 0.013 m 2.
（比較例８）
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例２と同様の非水電解質二次電池を作製した。 (Comparative Example 8)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 2, except that used was a 1 m 2 per 0.013 m 2.
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例２と同様の非水電解質二次電池を作製した。 (Comparative Example 8)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 2, except that used was a 1 m 2 per 0.013 m 2.
（比較例９）
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例３と同様の非水電解質二次電池を作製した。 (Comparative Example 9)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery as in Comparative Example 3 except for using those 1 m 2 per 0.013 m 2.
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例３と同様の非水電解質二次電池を作製した。 (Comparative Example 9)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery as in Comparative Example 3 except for using those 1 m 2 per 0.013 m 2.
（比較例１０）
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例４と同様の非水電解質二次電池を作製した。 (Comparative Example 10)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 4, except that used was a 1 m 2 per 0.013 m 2.
セパレータの表面積の差が１ｍ２あたり０．０１３ｍ２のものを用いた以外は比較例４と同様の非水電解質二次電池を作製した。 (Comparative Example 10)
The difference in surface area of the separator was used to fabricate a non-aqueous electrolyte secondary battery similar to that of Comparative Example 4, except that used was a 1 m 2 per 0.013 m 2.
＜充放電サイクル試験＞
実施例１～３および比較例１～１０の非水電解質二次電池を、それぞれ２５℃で０．７Ｉｔ（１８９０ｍＡ）の定電流で４．３Ｖまで充電し、さらに４．３Ｖで１／５０Ｉｔ（５４ｍＡ）になるまで定電圧充電を行った。次に２５℃で０．５Ｉｔ（１３５０ｍＡ）の定電流で３．０Ｖまで定電流放電を行った。この時の放電容量を記録した。そしてこのような充放電操作を１サイクルとして３００サイクル繰り返し、３００サイクル目の放電容
量を記録し、充放電サイクル後の残存容量を次の式により求め、充放電サイクル特性とした。
充放電サイクル後の残存容量（％）＝３００サイクル目の放電容量÷１サイクル目の放電容量×１００ <Charge / discharge cycle test>
The non-aqueous electrolyte secondary batteries of Examples 1 to 3 and Comparative Examples 1 to 10 were charged to 4.3 V at a constant current of 0.7 It (1890 mA) at 25 ° C., respectively, and further 1/50 It ( The constant voltage charge was performed until it reached 54 mA). Next, constant current discharge was performed to 25V at a constant current of 0.5 It (1350 mA) at 25 ° C. The discharge capacity at this time was recorded. Such a charge / discharge operation is repeated as 300 cycles, the discharge capacity at the 300th cycle is recorded, and the remaining capacity after the charge / discharge cycle is obtained by the following equation to obtain charge / discharge cycle characteristics.
Remaining capacity after charge / discharge cycle (%) = discharge capacity at 300th cycle / discharge capacity at 1st cycle × 100
実施例１～３および比較例１～１０の非水電解質二次電池を、それぞれ２５℃で０．７Ｉｔ（１８９０ｍＡ）の定電流で４．３Ｖまで充電し、さらに４．３Ｖで１／５０Ｉｔ（５４ｍＡ）になるまで定電圧充電を行った。次に２５℃で０．５Ｉｔ（１３５０ｍＡ）の定電流で３．０Ｖまで定電流放電を行った。この時の放電容量を記録した。そしてこのような充放電操作を１サイクルとして３００サイクル繰り返し、３００サイクル目の放電容
量を記録し、充放電サイクル後の残存容量を次の式により求め、充放電サイクル特性とした。
充放電サイクル後の残存容量（％）＝３００サイクル目の放電容量÷１サイクル目の放電容量×１００ <Charge / discharge cycle test>
The non-aqueous electrolyte secondary batteries of Examples 1 to 3 and Comparative Examples 1 to 10 were charged to 4.3 V at a constant current of 0.7 It (1890 mA) at 25 ° C., respectively, and further 1/50 It ( The constant voltage charge was performed until it reached 54 mA). Next, constant current discharge was performed to 25V at a constant current of 0.5 It (1350 mA) at 25 ° C. The discharge capacity at this time was recorded. Such a charge / discharge operation is repeated as 300 cycles, the discharge capacity at the 300th cycle is recorded, and the remaining capacity after the charge / discharge cycle is obtained by the following equation to obtain charge / discharge cycle characteristics.
Remaining capacity after charge / discharge cycle (%) = discharge capacity at 300th cycle / discharge capacity at 1st cycle × 100
上記の各実施例および比較例の試験結果を表１に示す。
Table 1 shows the test results of the above examples and comparative examples.
セパレータの表面積差が０．０３６ｍ２のものを用いた実施例１～３と比較例１～４において、極板に無機粒子層が形成され、セパレータの表面積が小さい面に対向して無機粒子層が形成されている実施例１～３は、セパレータの表面積が小さい面に対向して無機粒子層が形成されていない比較例１、２や、極板に無機粒子層が形成されていない比較例３、４と比較して、充放電サイクル後の残存容量が８０％を超えており良好であった。これ
は、実施例１～３の電池では、無機粒子層が形成された側に対向してセパレータの表面積が小さい面が配置され、つまりはセパレータの表面積の大きい面には無機粒子層がないので、無機粒子層側とセパレータの表面積の大きい面とに電解質がバランス良く配分されたためであると考えられる。 In Examples 1 to 3 and Comparative Examples 1 to 4 using a separator having a surface area difference of 0.036 m 2 , an inorganic particle layer is formed on the electrode plate, and the inorganic particle layer faces the surface having a small surface area of the separator. Examples 1 to 3 in which are formed are Comparative Examples 1 and 2 in which the inorganic particle layer is not formed facing the surface of the separator having a small surface area, or Comparative Examples in which the inorganic particle layer is not formed on the electrode plate Compared with 3 and 4, the remaining capacity after the charge / discharge cycle exceeded 80%, which was good. This is because, in the batteries of Examples 1 to 3, the surface having the small surface area of the separator is arranged opposite to the side on which the inorganic particle layer is formed, that is, the surface having the large surface area of the separator has no inorganic particle layer. This is probably because the electrolyte was distributed in a well-balanced manner between the inorganic particle layer side and the surface of the separator having a large surface area.
は、実施例１～３の電池では、無機粒子層が形成された側に対向してセパレータの表面積が小さい面が配置され、つまりはセパレータの表面積の大きい面には無機粒子層がないので、無機粒子層側とセパレータの表面積の大きい面とに電解質がバランス良く配分されたためであると考えられる。 In Examples 1 to 3 and Comparative Examples 1 to 4 using a separator having a surface area difference of 0.036 m 2 , an inorganic particle layer is formed on the electrode plate, and the inorganic particle layer faces the surface having a small surface area of the separator. Examples 1 to 3 in which are formed are Comparative Examples 1 and 2 in which the inorganic particle layer is not formed facing the surface of the separator having a small surface area, or Comparative Examples in which the inorganic particle layer is not formed on the electrode plate Compared with 3 and 4, the remaining capacity after the charge / discharge cycle exceeded 80%, which was good. This is because, in the batteries of Examples 1 to 3, the surface having the small surface area of the separator is arranged opposite to the side on which the inorganic particle layer is formed, that is, the surface having the large surface area of the separator has no inorganic particle layer. This is probably because the electrolyte was distributed in a well-balanced manner between the inorganic particle layer side and the surface of the separator having a large surface area.
一方、比較例１、２では、無機粒子層が形成された側にはセパレータの表面積が小さい面が対向しておらず、つまりはセパレータの表面積が大きい面に対向して無機粒子層が形成されているため、電解質は無機粒子層とセパレータの表面積が大きい面とが対向する部分に集中し、電解質の配分のバランスが崩れて、充放電サイクル特性は実施例よりも劣るものとなったと考えられる。
On the other hand, in Comparative Examples 1 and 2, the surface on which the inorganic particle layer is formed does not face the surface having a small surface area of the separator, that is, the inorganic particle layer is formed to face the surface having a large surface area of the separator. Therefore, the electrolyte is concentrated on the portion where the inorganic particle layer and the surface having a large surface area of the separator face each other, the balance of the electrolyte distribution is lost, and the charge / discharge cycle characteristics are considered to be inferior to those of the examples. .
また、極板に無機粒子層を形成しなかった比較例３、４は、比較例１、２よりも若干特性はよいが、実施例１～３よりも劣っていた。これは、比較例１、２よりも電解質の分配のバランスは若干良いが、セパレータの表面積の大きい面に電解質が偏っているものと考えられる。
Further, Comparative Examples 3 and 4 in which the inorganic particle layer was not formed on the electrode plate had slightly better characteristics than Comparative Examples 1 and 2, but were inferior to Examples 1 to 3. This is considered that the balance of electrolyte distribution is slightly better than those of Comparative Examples 1 and 2, but the electrolyte is biased to the surface of the separator having a large surface area.
セパレータの表面積差の大小について、セパレータの表面積の差が１ｍ２あたり０．０３６ｍ２実施例１～３と表面積の差が０．０１３ｍ２の比較例５、６を比較すると、実施例１～３の充放電サイクル特性が良好であることが判る。これは、比較例５、６のセパレータの表面積差が小さく、極板の無機粒子層側に電解質配分のバランスが偏ったためと考えられる。したがって、セパレータの一方面と他方面との表面積の差は１ｍ２あたり０．
０３６ｍ２以上必要である。 The magnitude of the difference in surface area of the separator, when the difference in surface area of the separator is the difference between the surface area and 1 m 2 per 0.036 m 2 Example 1-3 to compare the comparative examples 5 and 6 of 0.013 m 2, Examples 1-3 It can be seen that the charge / discharge cycle characteristics are good. This is probably because the difference in surface area between the separators of Comparative Examples 5 and 6 was small, and the balance of electrolyte distribution was biased toward the inorganic particle layer side of the electrode plate. Therefore, the difference in surface area between the one surface and the other surface of the separator is 0.00 per m 2 .
036 m 2 or more is necessary.
０３６ｍ２以上必要である。 The magnitude of the difference in surface area of the separator, when the difference in surface area of the separator is the difference between the surface area and 1 m 2 per 0.036 m 2 Example 1-3 to compare the comparative examples 5 and 6 of 0.013 m 2, Examples 1-3 It can be seen that the charge / discharge cycle characteristics are good. This is probably because the difference in surface area between the separators of Comparative Examples 5 and 6 was small, and the balance of electrolyte distribution was biased toward the inorganic particle layer side of the electrode plate. Therefore, the difference in surface area between the one surface and the other surface of the separator is 0.00 per m 2 .
036 m 2 or more is necessary.
無機粒子層に酸化チタンを用いた実施例１と酸化アルミニウムを用いた実施例３を比較すると、充放電サイクル特性にほとんど差がなく良好である。したがって、無機粒子層に用いる材料には、絶縁性の金属酸化物を用いることができる。
Comparing Example 1 using titanium oxide for the inorganic particle layer and Example 3 using aluminum oxide, the charge / discharge cycle characteristics are almost the same and good. Therefore, an insulating metal oxide can be used for the material used for the inorganic particle layer.
なお、上記実施の形態においては、巻回式の電極体を用いたが、積層式の電極体を用いても同様の効果がある。また、正極としてリチウム遷移金属複合酸化物である六方晶形コバルト酸リチウムと層状ニッケルマンガンコバルト酸リチウムとの混合正極活物質を用いたが、正極活物質としてコバルト酸リチウムのみを用いてもよく、ニッケル酸リチウムやマンガン酸リチウムなどを用いてもよい。またリチウム遷移金属複合酸化物の遷移金属を
他の元素と置換したものや、リチウム遷移金属複合酸化物に他の元素単体や化合物を添加してもよい。 In the above-described embodiment, the wound electrode body is used. However, the same effect can be obtained by using a laminated electrode body. Moreover, although the mixed positive electrode active material of the hexagonal type lithium cobalt oxide which is a lithium transition metal complex oxide and a layered nickel manganese lithium cobalt oxide was used as the positive electrode, the lithium cobalt oxide alone may be used as the positive electrode active material. Lithium acid oxide, lithium manganate, or the like may be used. In addition, the transition metal of the lithium transition metal composite oxide may be replaced with another element, or another element simple substance or compound may be added to the lithium transition metal composite oxide.
他の元素と置換したものや、リチウム遷移金属複合酸化物に他の元素単体や化合物を添加してもよい。 In the above-described embodiment, the wound electrode body is used. However, the same effect can be obtained by using a laminated electrode body. Moreover, although the mixed positive electrode active material of the hexagonal type lithium cobalt oxide which is a lithium transition metal complex oxide and a layered nickel manganese lithium cobalt oxide was used as the positive electrode, the lithium cobalt oxide alone may be used as the positive electrode active material. Lithium acid oxide, lithium manganate, or the like may be used. In addition, the transition metal of the lithium transition metal composite oxide may be replaced with another element, or another element simple substance or compound may be added to the lithium transition metal composite oxide.
また、上記実施の形態において、負極活物質として黒鉛を用いたが、コークス等の他の炭素材料を用いることができる。また、ケイ素やその酸化物、合金系、酸化物系の負極活物質を用いることもできる。
In the above embodiment, graphite is used as the negative electrode active material, but other carbon materials such as coke can be used. Moreover, silicon, its oxide, an alloy type, and an oxide type negative electrode active material can also be used.
また、上記実施の形態において、セパレータはポリエチレン製で微多孔を有するものを用いたが、ポリプロピレンのようなポリエチレン以外のポリオレフィン製としてもよい。またポリオレフィン以外の樹脂製微多孔膜を用いることも可能である。
また、上記実施の形態において、１枚の膜を延伸等の製造条件を調整することで両面の表面積に差を生じさせたが、２枚以上の微多孔膜を貼り合わせたものであって、一方面と他方面で表面積の差がある微多孔膜も用いることができる。このとき、例えばポリエチレンとポリプロピレンのように、性質の異なる２枚以上の膜を貼り合わせて用いることも可能である。 In the above embodiment, the separator is made of polyethylene and has micropores. However, the separator may be made of polyolefin other than polyethylene such as polypropylene. It is also possible to use a resin microporous membrane other than polyolefin.
Further, in the above embodiment, a difference was made in the surface area of both surfaces by adjusting the production conditions such as stretching one film, but two or more microporous films were bonded together, A microporous membrane having a surface area difference between the one surface and the other surface can also be used. At this time, for example, two or more films having different properties, such as polyethylene and polypropylene, can be used together.
また、上記実施の形態において、１枚の膜を延伸等の製造条件を調整することで両面の表面積に差を生じさせたが、２枚以上の微多孔膜を貼り合わせたものであって、一方面と他方面で表面積の差がある微多孔膜も用いることができる。このとき、例えばポリエチレンとポリプロピレンのように、性質の異なる２枚以上の膜を貼り合わせて用いることも可能である。 In the above embodiment, the separator is made of polyethylene and has micropores. However, the separator may be made of polyolefin other than polyethylene such as polypropylene. It is also possible to use a resin microporous membrane other than polyolefin.
Further, in the above embodiment, a difference was made in the surface area of both surfaces by adjusting the production conditions such as stretching one film, but two or more microporous films were bonded together, A microporous membrane having a surface area difference between the one surface and the other surface can also be used. At this time, for example, two or more films having different properties, such as polyethylene and polypropylene, can be used together.
本発明によれば、充放電サイクル特性に優れた非水電解質二次電池を提供できるので、産業上の利用可能性が大である。
According to the present invention, a non-aqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics can be provided, so that industrial applicability is great.
１ 正極
２ 負極
３ 無機粒子層
４ セパレータ
４１ 表面積の大きい面
４２ 表面積の小さい面
DESCRIPTION OFSYMBOLS 1 Positive electrode 2 Negative electrode 3 Inorganic particle layer 4 Separator 41 Surface with large surface area 42 Surface with small surface area
２ 負極
３ 無機粒子層
４ セパレータ
４１ 表面積の大きい面
４２ 表面積の小さい面
DESCRIPTION OF
Claims (3)
- 正極と負極がセパレータを介して対向してなる電極体と、非水電解質を備える非水電解質二次電池であって、
前記正極または前記負極のいずれか一方極の表面に無機材料粒子からなる無機粒子層を備え、
前記セパレータは、一方面と他方面とで表面積の差が１ｍ２あたり０．０３６ｍ２以上であり、
前記セパレータの表面積の小さい面と、前記一方極の無機粒子層とが対向していることを特徴とする非水電解質二次電池。 An electrode body in which a positive electrode and a negative electrode face each other with a separator interposed therebetween, and a nonaqueous electrolyte secondary battery comprising a nonaqueous electrolyte,
Provided with an inorganic particle layer composed of inorganic material particles on the surface of either the positive electrode or the negative electrode,
The separator has a surface area difference of 0.036 m 2 or more per 1 m 2 on one side and the other side,
A nonaqueous electrolyte secondary battery, wherein a surface of the separator having a small surface area is opposed to the inorganic particle layer of the one electrode. - 前記無機粒子層を構成する無機材料は、絶縁性の金属酸化物であることを特徴とする請求項１に記載の非水電解質二次電池。 The non-aqueous electrolyte secondary battery according to claim 1, wherein the inorganic material constituting the inorganic particle layer is an insulating metal oxide.
- 前記絶縁性の金属酸化物は、酸化チタンと酸化アルミニウムから選択される少なくとも１種であることを特徴とする請求項２に記載の非水電解質二次電池。 The non-aqueous electrolyte secondary battery according to claim 2, wherein the insulating metal oxide is at least one selected from titanium oxide and aluminum oxide.
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