JP6679895B2 - Electric storage element and manufacturing method thereof - Google Patents

Electric storage element and manufacturing method thereof Download PDF

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JP6679895B2
JP6679895B2 JP2015226797A JP2015226797A JP6679895B2 JP 6679895 B2 JP6679895 B2 JP 6679895B2 JP 2015226797 A JP2015226797 A JP 2015226797A JP 2015226797 A JP2015226797 A JP 2015226797A JP 6679895 B2 JP6679895 B2 JP 6679895B2
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positive electrode
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separator
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coating
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JP2017097999A (en
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平田　和希
和希 平田
真司 大西
真司 大西
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Denso Corp
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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
    • 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

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Description

本発明は、蓄電素子及びその製造方法に関する。   The present invention relates to a storage element and a method for manufacturing the same.

従来より、正極活物質の表面に無機酸化物層が設けられた構成が、例えば特許文献１で提案されている。正極活物質は充放電可能な二次電池の正極を構成している。無機酸化物層は、正極活物質に電圧が印加された際に、正極活物質と電解液物質とが反応することを抑制する役割を果たす。   Conventionally, for example, Patent Document 1 proposes a configuration in which an inorganic oxide layer is provided on the surface of a positive electrode active material. The positive electrode active material constitutes the positive electrode of a rechargeable secondary battery. The inorganic oxide layer plays a role of suppressing the reaction between the positive electrode active material and the electrolyte solution substance when a voltage is applied to the positive electrode active material.

特開２０１４−１１６１１１号公報JP, 2014-116111, A

しかしながら、上記従来の技術では、無機酸化物層は絶縁物質によって構成されているので、無機酸化物層が設けられた正極活物質を用いて電極を作製すると、電極内の電子伝導性が低下してしまう。このため、電池性能が低下してしまうという問題がある。   However, in the above conventional technique, since the inorganic oxide layer is composed of an insulating material, when an electrode is produced using a positive electrode active material provided with the inorganic oxide layer, the electron conductivity in the electrode is lowered. Will end up. Therefore, there is a problem that the battery performance is deteriorated.

本発明は上記点に鑑み、正極活物質の電子伝導性を確保しつつ、正極と電解質物質との反応における抵抗成分の生成を抑制することにより電池性能を向上させることができる蓄電素子を提供することを第１の目的とする。また、当該蓄電素子の製造方法を提供することを第２の目的とする。   In view of the above points, the present invention provides a power storage device capable of improving battery performance by suppressing generation of a resistance component in a reaction between a positive electrode and an electrolyte substance while ensuring electronic conductivity of the positive electrode active material. This is the first purpose. A second object is to provide a method for manufacturing the power storage element.

上記目的を達成するため、請求項１に記載の発明では、金属イオンを吸蔵放出可能な正極活物質（４２）を主成分とする正極（４０）と、金属イオンを吸蔵放出可能な負極活物質（５２）を主成分とする負極（５０）と、を備えている。また、正極と負極とに挟まれており、金属イオンの伝導性を有すると共に、正極と負極とを電気的に絶縁分離するセパレータ（６０）を備えている。 In order to achieve the above object, in the invention according to claim 1 , a positive electrode (40) containing a positive electrode active material (42) capable of occluding and releasing metal ions as a main component, and a negative electrode active material capable of occluding and releasing metal ions. And a negative electrode (50) containing (52) as a main component. Further, it is sandwiched between the positive electrode and the negative electrode, and has a separator (60) which has conductivity of metal ions and electrically insulates and separates the positive electrode and the negative electrode.

また、正極に接続された正極端子（２０）と、負極に接続された負極端子（３０）と、を備えている。セパレータが正極と負極とに挟まれた状態で、セパレータ、正極、負極、正極端子の一部、及び負極端子の一部を収容室（１８）に収容する筐体（１０）を備えている。さらに、収容室のうち、当該収容室の壁面（１９）、セパレータ、正極、負極、正極端子の一部、及び負極端子の一部によって構成された表面の全体を覆う金属酸化物の被膜（７１）を備えている。   Further, it is provided with a positive electrode terminal (20) connected to the positive electrode and a negative electrode terminal (30) connected to the negative electrode. The housing (10) accommodates the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal in the accommodation chamber (18) with the separator sandwiched between the positive electrode and the negative electrode. Further, in the storage chamber, a metal oxide coating film (71) covering the entire wall surface (19) of the storage chamber, the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal. ) Is provided.

請求項５に記載の発明では、金属イオンを吸蔵放出可能な正極活物質（４２）を主成分とする正極（４０）を用意する。また、金属イオンを吸蔵放出可能な負極活物質（５２）を主成分とする負極（５０）を用意する。 According to the invention of claim 5 , a positive electrode (40) containing a positive electrode active material (42) capable of inserting and extracting metal ions as a main component is prepared. Further, a negative electrode (50) containing a negative electrode active material (52) capable of inserting and extracting metal ions as a main component is prepared.

次に、金属イオンの伝導性を有すると共に、正極と負極とを電気的に絶縁分離するセパレータ（６０）を用意し、セパレータを正極と負極とで挟む。そして、正極に正極端子（２０）を接続する。また、負極に負極端子（３０）を接続する。   Next, a separator (60) having metal ion conductivity and electrically insulating and separating the positive electrode and the negative electrode is prepared, and the separator is sandwiched between the positive electrode and the negative electrode. Then, the positive electrode terminal (20) is connected to the positive electrode. Further, the negative electrode terminal (30) is connected to the negative electrode.

続いて、収容室（１８）を有する筐体（１０）を用意し、セパレータ、正極、負極、正極端子の一部、及び負極端子の一部を収容室に収容する。この後、収容室のうち、当該収容室の壁面（１９）、セパレータ、正極、負極、正極端子の一部、及び負極端子の一部によって構成された表面の全体を覆う金属酸化物の被膜（７１）を形成する。   Subsequently, the housing (10) having the accommodation chamber (18) is prepared, and the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal are accommodated in the accommodation chamber. After that, a metal oxide film (which covers the entire wall surface (19) of the accommodation chamber, the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal in the accommodation chamber ( 71) is formed.

上記のように、金属酸化物の第１被膜が正極の表面の全体を覆う構成となるので、正極活物質の電流パスに第１被膜が介在しないようにすることができる。このため、正極活物質の電子伝導性を確保することができる。また、第１被膜によって正極活物質が電解液に接触しないので、電解液に含まれる電解質物質と正極活物質との反応における抵抗成分の生成を抑制することができる。したがって、蓄電素子の電池性能の低下を抑制することができる。   As described above, since the first coating of the metal oxide covers the entire surface of the positive electrode, it is possible to prevent the first coating from intervening in the current path of the positive electrode active material. Therefore, the electron conductivity of the positive electrode active material can be secured. Further, since the positive electrode active material does not come into contact with the electrolytic solution by the first coating, it is possible to suppress the generation of the resistance component in the reaction between the electrolytic material contained in the electrolytic solution and the positive electrode active material. Therefore, deterioration of the battery performance of the power storage element can be suppressed.

なお、この欄及び特許請求の範囲で記載した各手段の括弧内の符号は、後述する実施形態に記載の具体的手段との対応関係を示すものである。   It should be noted that the reference numerals in parentheses for each means described in this column and in the claims indicate the correspondence with the specific means described in the embodiments described later.

本発明の第１実施形態に係る蓄電素子の斜視図である。FIG. 3 is a perspective view of the electricity storage device according to the first embodiment of the present invention. 図１に示された蓄電素子の断面図である。FIG. 2 is a cross-sectional view of the electricity storage device shown in FIG. 1. 図２に示された正極、負極、及びセパレータの拡大断面図である。FIG. 3 is an enlarged cross-sectional view of the positive electrode, the negative electrode, and the separator shown in FIG. 2. 第１実施形態に係る蓄電素子の製造工程を示した図である。It is a figure showing a manufacturing process of a storage element concerning a 1st embodiment. サイクル数と容量維持率との相関関係を示した図である。It is a figure showing the correlation of the cycle number and capacity maintenance rate. 活物質あたりの容量と電圧との相関関係を示した図である。FIG. 6 is a diagram showing a correlation between a capacity per active material and a voltage. 本発明の第２実施形態に係る正極、負極、及びセパレータの拡大断面図である。It is an expanded sectional view of a positive electrode, a negative electrode, and a separator concerning a 2nd embodiment of the present invention. 第２実施形態に係る蓄電素子の製造工程を示した図である。It is a figure showing the manufacturing process of the electric storage element concerning a 2nd embodiment. 第３実施形態に係る蓄電素子のうち正極端子の近傍の拡大断面図である。It is an expanded sectional view near the positive electrode terminal among the electric storage elements concerning a 3rd embodiment. 第３実施形態に係る蓄電素子の製造工程を示した図である。It is a figure showing a manufacturing process of a storage element concerning a 3rd embodiment.

以下、本発明の実施形態について図に基づいて説明する。なお、以下の各実施形態相互において、互いに同一もしくは均等である部分には、図中、同一符号を付してある。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following respective embodiments, the same or equivalent parts are designated by the same reference numerals in the drawings.

（第１実施形態）
以下、本発明の第１実施形態について図を参照して説明する。本実施形態に係る蓄電素子は、正負極間における電解質イオンに伴う電荷の移動により充放電が実現される二次電池である。電解質イオンは、リチウムイオン等の金属イオンである。 (First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The electricity storage device according to the present embodiment is a secondary battery in which charge and discharge are realized by the movement of charges due to electrolyte ions between the positive and negative electrodes. The electrolyte ions are metal ions such as lithium ions.

図１及び図２に示されるように、蓄電素子１は、筐体１０、正極端子２０、負極端子３０、複数の正極４０、複数の負極５０、及び複数のセパレータ６０を備えて構成されている。なお、図３では、積層体７０の積層構造を見やすくするために、セパレータ６０の断面を破線で表現している。セパレータ６０は、実際はシート状である。   As shown in FIGS. 1 and 2, the electricity storage device 1 includes a housing 10, a positive electrode terminal 20, a negative electrode terminal 30, a plurality of positive electrodes 40, a plurality of negative electrodes 50, and a plurality of separators 60. . Note that in FIG. 3, the cross section of the separator 60 is represented by a broken line in order to make the laminated structure of the laminated body 70 easy to see. The separator 60 is actually a sheet.

蓄電素子１は、積層体７０が筐体１０を構成するラミネートフィルム１１、１２に封止されたラミネート型のものである。積層体７０は、各ラミネートフィルム１１、１２にエンボス加工等によって形成された凹部１３、１４に収容されている。   The electricity storage device 1 is of a laminate type in which a laminate 70 is sealed in laminate films 11 and 12 that form the housing 10. The laminated body 70 is accommodated in the recesses 13 and 14 formed in the laminated films 11 and 12 by embossing or the like.

積層体７０は、正極４０と負極５０とがセパレータ６０を介して積層されたものがさらに複数積層されて構成されている。積層体７０は、凹部１３、１４の底面よりわずかに小さい面を含む直方体の形状を有する。積層体７０の最上層及び最下層は負極５０になっている。   The laminated body 70 is configured by further laminating a plurality of the positive electrodes 40 and the negative electrodes 50 that are laminated via the separator 60. The laminated body 70 has a rectangular parallelepiped shape including a surface slightly smaller than the bottom surfaces of the recesses 13 and 14. The uppermost layer and the lowermost layer of the laminated body 70 are the negative electrode 50.

各ラミネートフィルム１１、１２の外周縁１５は、凹部１３、１４の外縁部に位置すると共に、相互に当接する面である。外周縁１５は加熱融着等の方法によって接合されている。   The outer peripheral edge 15 of each of the laminate films 11 and 12 is a surface located at the outer edge of the recesses 13 and 14 and abutting against each other. The outer peripheral edge 15 is joined by a method such as heat fusion.

正極端子２０及び負極端子３０は、ラミネートフィルム１１、１２の外周縁１５でタブフィルム１６、１７を介して封口されている。タブフィルム１６、１７は、例えば酸変性のポリプロピレン等によって構成されている。タブフィルム１６、１７は極性があるので、接着性を有する。   The positive electrode terminal 20 and the negative electrode terminal 30 are sealed at the outer peripheral edge 15 of the laminate films 11 and 12 via tab films 16 and 17. The tab films 16 and 17 are made of, for example, acid-modified polypropylene or the like. Since the tab films 16 and 17 have polarities, they have adhesiveness.

正極端子２０は、一端側が複数の正極４０に接続されていると共に、他端側が外周縁１５の外部に突出している。同様に、負極端子３０は、一端側が複数の負極５０に接続されていると共に、他端側が外周縁１５の外部に突出している。   One end of the positive electrode terminal 20 is connected to the plurality of positive electrodes 40, and the other end thereof projects outside the outer peripheral edge 15. Similarly, the negative electrode terminal 30 has one end connected to the plurality of negative electrodes 50 and the other end protruding outside the outer peripheral edge 15.

したがって、筐体１０は、各ラミネートフィルム１１、１２の凹部１３、１４によって構成される収容室１８に、積層体７０、正極端子２０の一部、及び負極端子３０の一部を収容している。なお、タブフィルム１６、１７は筐体１０の収容室１８の壁面１９の一部を構成している。   Therefore, the housing 10 houses the laminated body 70, a part of the positive electrode terminal 20, and a part of the negative electrode terminal 30 in the housing chamber 18 formed by the recesses 13 and 14 of the laminate films 11 and 12, respectively. . The tab films 16 and 17 form a part of the wall surface 19 of the housing chamber 18 of the housing 10.

図３に示されるように、正極４０は、正極集電体４１、正極活物質４２、導電材４３、及び第１被膜４４を有している。また、負極５０は、負極集電体５１、負極活物質５２、及び第２被膜５３を有している。   As shown in FIG. 3, the positive electrode 40 has a positive electrode current collector 41, a positive electrode active material 42, a conductive material 43, and a first coating film 44. Further, the negative electrode 50 has a negative electrode current collector 51, a negative electrode active material 52, and a second coating 53.

具体的に、正極４０は、アルミ箔の正極集電体４１の両面に、酸化剤として正極活物質４２が積層されたものである。正極４０は、この正極活物質４２を主成分としている。負極５０は、銅箔の負極集電体５１の両面に、還元剤として負極活物質５２が積層されたものである。負極５０は、この負極活物質５２を主成分としている。   Specifically, the positive electrode 40 is formed by laminating a positive electrode active material 42 as an oxidizing agent on both surfaces of a positive electrode current collector 41 made of aluminum foil. The positive electrode 40 has this positive electrode active material 42 as a main component. The negative electrode 50 is obtained by laminating a negative electrode active material 52 as a reducing agent on both surfaces of a negative electrode current collector 51 made of copper foil. The negative electrode 50 has this negative electrode active material 52 as a main component.

正極集電体４１及び負極集電体５１は、電気を取り出すための端子としての役割を果たす。正極集電体４１は複数束ねられて正極端子２０の一端側に接続されている。同様に、負極集電体５１は複数束ねられて負極端子３０の一端側に接続されている。   The positive electrode current collector 41 and the negative electrode current collector 51 serve as terminals for extracting electricity. A plurality of positive electrode current collectors 41 are bundled and connected to one end side of the positive electrode terminal 20. Similarly, a plurality of negative electrode current collectors 51 are bundled and connected to one end side of the negative electrode terminal 30.

正極活物質４２及び負極活物質５２は、金属イオンを送り出し受け取る酸化／還元反応を行う物質である。すなわち、正極活物質４２及び負極活物質５２は、金属イオンとしてリチウムイオンを吸蔵放出可能な化合物である。   The positive electrode active material 42 and the negative electrode active material 52 are materials that perform an oxidation / reduction reaction by sending out and receiving metal ions. That is, the positive electrode active material 42 and the negative electrode active material 52 are compounds capable of inserting and extracting lithium ions as metal ions.

正極活物質４２として、例えば、コバルト酸リチウム（ＬｉＣｏＯ２）、リン酸鉄リチウム（ＬｉＦｅＰＯ４）、マンガン酸リチウム（ＬｉＭｎＰＯ４）、ＬｉＮｉ０．５Ｍｎ１．５Ｏ４等が用いられる。負極活物質５２として、例えば炭素（Ｃ）やチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）等が用いられる。 As the positive electrode active material 42, for example, lithium cobalt oxide (LiCoO 2 ), lithium iron phosphate (LiFePO 4 ), lithium manganate (LiMnPO 4 ), LiNi 0.5 Mn 1.5 O 4 or the like is used. As the negative electrode active material 52, for example, carbon (C), lithium titanate (Li 4 Ti 5 O 12 ) or the like is used.

導電材４３は、正極活物質４２に電子の供給パスを提供する役割を果たす。導電材４３として、例えば炭素材料、金属粉、導電性ポリマー等が用いられる。   The conductive material 43 plays a role of providing an electron supply path to the positive electrode active material 42. As the conductive material 43, for example, a carbon material, metal powder, conductive polymer or the like is used.

第１被膜４４は、正極４０を構成する正極集電体４１、正極活物質４２、及び導電材４３とセパレータ６０に含まれる電解液とが反応することを抑制する役割を果たす膜である。第１被膜４４は、正極４０の表面の全体を覆っている。   The first coating film 44 is a film that plays a role of suppressing the reaction between the positive electrode current collector 41, the positive electrode active material 42, and the conductive material 43 that form the positive electrode 40 and the electrolytic solution included in the separator 60. The first coating 44 covers the entire surface of the positive electrode 40.

ここで、正極４０の表面とは、正極集電体４１、正極活物質４２、及び導電材４３のうち、これらが互いに接触する接触面を除いた表面全体である。言い換えると、正極４０の表面とは、正極４０に第１被膜４４が設けられていない状態で正極集電体４１、正極活物質４２、及び導電材４３が露出する表面である。   Here, the surface of the positive electrode 40 is the entire surface of the positive electrode current collector 41, the positive electrode active material 42, and the conductive material 43 excluding the contact surfaces that contact each other. In other words, the surface of the positive electrode 40 is the surface where the positive electrode current collector 41, the positive electrode active material 42, and the conductive material 43 are exposed in the state where the first coating film 44 is not provided on the positive electrode 40.

同様に、第２被膜５３は、負極５０を構成する負極集電体５１及び負極活物質５２と電解液とが反応することを抑制する役割を果たす膜である。第２被膜５３は、負極５０の表面の全体を覆っている。負極５０の表面は、正極４０の表面と同様に定義される。   Similarly, the second coating 53 is a film that plays a role of suppressing the reaction between the negative electrode current collector 51 and the negative electrode active material 52 that form the negative electrode 50 and the electrolytic solution. The second coating 53 covers the entire surface of the negative electrode 50. The surface of the negative electrode 50 is defined similarly to the surface of the positive electrode 40.

なお、負極５０には正極４０を構成する導電材４３が含まれていても良い。負極５０に導電材４３が含まれる場合、第２被膜５３は負極５０内の導電性を確保した状態で負極５０の表面全体を覆うことになる。   The negative electrode 50 may include the conductive material 43 forming the positive electrode 40. When the negative electrode 50 includes the conductive material 43, the second coating 53 covers the entire surface of the negative electrode 50 while ensuring conductivity inside the negative electrode 50.

そして、各被膜４４、５３は、金属酸化物によって構成されている。一つの例として、金属酸化物は、Ａｌ、Ｔｉ、Ｓｉのうちの少なくとも１つを含む酸化物である。例えば、Ａｌ２Ｏ５、ＴｉＯ２、ＳｉＯ２を少なくとも１つ含む酸化物である。 Each of the coatings 44 and 53 is made of metal oxide. As one example, the metal oxide is an oxide containing at least one of Al, Ti, and Si. For example, it is an oxide containing at least one of Al 2 O 5 , TiO 2 , and SiO 2 .

また、別の例として、金属酸化物は、少なくともＡｌを含むと共に、Ｔｉ及びＳｉのうちの少なくとも１つを含む酸化物である。例えば、Ａｌ２Ｏ５、ＴｉＯ２、ＳｉＯ２を同一層内に含む酸化物である。 Further, as another example, the metal oxide is an oxide containing at least Al and at least one of Ti and Si. For example, it is an oxide containing Al 2 O 5 , TiO 2 , and SiO 2 in the same layer.

さらに別の例として、金属酸化物は、Ｌｉを含む酸化物である。例えば、ＬｉＡｌＯ４、Ｌｉ４Ｔｉ５Ｏ１２、ＬｉＳｉＯ４である。 As still another example, the metal oxide is an oxide containing Li. For example, LiAlO 4 , Li 4 Ti 5 O 12 , and LiSiO 4 .

本実施形態では、第１被膜４４と第２被膜５３は同一の金属酸化物によって構成されている。なお、本実施形態に係る蓄電素子１の構成では、第１被膜４４と第２被膜５３は別々の金属酸化物によって構成されていても良い。   In the present embodiment, the first coating 44 and the second coating 53 are made of the same metal oxide. In addition, in the configuration of the electricity storage device 1 according to the present embodiment, the first coating 44 and the second coating 53 may be configured by different metal oxides.

セパレータ６０は、正極４０と負極５０とを電気的に絶縁分離すると共に、電解液を保持する役割を果たすものである。セパレータ６０は、正極４０と負極５０とに挟まれている。すなわち、セパレータ６０は、正極４０に設けられた第１被膜４４と、負極５０に設けられた第２被膜５３と、に接触している。ここで、第１被膜４４のうちセパレータ６０に接触する部分は、正極活物質４２や導電材４３を覆う部分に限定されている。また、第２被膜５３のうちセパレータ６０に接触する部分は負極活物質５２を覆う部分に限定されている。   The separator 60 plays a role of electrically insulating and separating the positive electrode 40 and the negative electrode 50 and holding an electrolytic solution. The separator 60 is sandwiched between the positive electrode 40 and the negative electrode 50. That is, the separator 60 is in contact with the first coating film 44 provided on the positive electrode 40 and the second coating film 53 provided on the negative electrode 50. Here, the portion of the first coating 44 that contacts the separator 60 is limited to the portion that covers the positive electrode active material 42 and the conductive material 43. Further, the portion of the second coating 53 that contacts the separator 60 is limited to the portion that covers the negative electrode active material 52.

また、セパレータ６０は、金属イオンの伝導性を有している。つまり、セパレータ６０は、電子を通さないが、金属イオンを通す性質を持つ。セパレータ６０として、ポリエチレンやポリプロピレン等の多孔性合成樹脂膜が用いられる。セパレータ６０は図示しない電解液を含んだ構成になっている。電解液は、セパレータ６０と正極４０との空隙、及び、セパレータ６０と負極５０との空隙にも設けられている。なお、セパレータ６０は表面及び内部にセラミック粒子を備えていても良い。以上が本実施形態に係る蓄電素子１の全体構成である。   Further, the separator 60 has metal ion conductivity. That is, the separator 60 has a property of allowing electrons to pass therethrough but allowing metal ions to pass therethrough. As the separator 60, a porous synthetic resin film such as polyethylene or polypropylene is used. The separator 60 is configured to include an electrolytic solution (not shown). The electrolytic solution is also provided in the gap between the separator 60 and the positive electrode 40 and the gap between the separator 60 and the negative electrode 50. The separator 60 may include ceramic particles on the surface and inside. The above is the overall configuration of the electricity storage device 1 according to the present embodiment.

次に、蓄電素子１の製造方法について、図４を参照して説明する。まず、正極４０及び負極５０を用意する。正極４０及び負極５０の形成方法は同じであるので、正極４０を用意する工程を例に説明する。   Next, a method for manufacturing the storage element 1 will be described with reference to FIG. First, the positive electrode 40 and the negative electrode 50 are prepared. Since the method of forming the positive electrode 40 and the negative electrode 50 is the same, the step of preparing the positive electrode 40 will be described as an example.

はじめに、正極活物質４２、導電材４３、及び結着材からなる正極合材を溶媒に混ぜて混練する調合・混連工程を行う。続いて、ペースト状の正極合材を正極集電体４１の両面に塗布する塗布工程を行うと共に、正極合材の密度調整のためのプレス工程を行う。プレス工程が終了した正極４０はロール状に巻かれた状態になっていることが多いが、その限りではない。また、正極４０内の水分・溶媒除去を目的に減圧室で真空乾燥工程を行うこともある。   First, a compounding / mixing step of mixing and kneading the positive electrode mixture material including the positive electrode active material 42, the conductive material 43, and the binder in a solvent is performed. Subsequently, a coating step of applying a paste-like positive electrode mixture material to both surfaces of the positive electrode current collector 41 is performed, and a pressing step for adjusting the density of the positive electrode mixture material is performed. The positive electrode 40 after the pressing process is often wound into a roll, but this is not the case. In addition, a vacuum drying process may be performed in a decompression chamber for the purpose of removing water and solvent in the positive electrode 40.

この後、第１被膜４４を形成する被膜形成工程を行う。被膜形成は、原子層堆積法（Atomic Layer Deposition；ＡＬＤ）を用いて行う。ＡＬＤ法は、正極４０の表面に例えば水を吸着させた後に原料ガスを流すことで、正極４０の表面に吸着した水と原料との表面反応により、正極４０の表面に非常に薄い膜を形成する方法である。ＡＬＤ法では、４ステップを１サイクルとして製膜を行う。   After that, a film forming step of forming the first film 44 is performed. The film formation is performed using an atomic layer deposition method (Atomic Layer Deposition; ALD). In the ALD method, for example, by adsorbing water on the surface of the positive electrode 40 and then flowing a raw material gas, a surface reaction between the water adsorbed on the surface of the positive electrode 40 and the raw material forms a very thin film on the surface of the positive electrode 40. Is the way to do it. In the ALD method, film formation is performed with 4 steps as one cycle.

正極４０の電極表面全体に第１被膜４４を製膜するため、正極４０をチャンバに設置する。チャンバに設置する正極４０は、ロール状のものでも、電池セルサイズにカットしたものでも良く、それらが複数セット存在している状態でも良い。   In order to form the first coating film 44 on the entire electrode surface of the positive electrode 40, the positive electrode 40 is installed in the chamber. The positive electrode 40 installed in the chamber may be in the form of a roll, may be cut into battery cell sizes, or may be in a state in which a plurality of sets thereof are present.

そして、チャンバ内温度を１００℃に設定し、原料であるＴＭＡ（トリメチルアルミニウム）を１５℃、水（Ｈ２Ｏ）を２５℃として、第１被膜４４を製膜する。製膜条件としては、ＴＭＡガス輸送を０．３ｓｅｃ、パージを０．９ｓｅｃとし、Ｈ２Ｏガス輸送を０．３ｓｅｃ、パージを０．９ｓｅｃとして製膜を実施した。 Then, the temperature inside the chamber is set to 100 ° C., the raw material TMA (trimethylaluminum) is set to 15 ° C., and the water (H 2 O) is set to 25 ° C. to form the first coating film 44. As film forming conditions, TMA gas transportation was 0.3 sec, purging was 0.9 sec, H 2 O gas transportation was 0.3 sec, and purging was 0.9 sec.

なお、製膜の温度が低いため、ガス粘性を考慮して各製膜条件を十分大きく設定することが好ましい。また、発明者らは、正極活物質４２や導電材４３に全面に均一、且つ、サイクル数に比例した膜厚で着膜することを確認した。   Since the film forming temperature is low, it is preferable to set each film forming condition sufficiently large in consideration of gas viscosity. The inventors have also confirmed that the positive electrode active material 42 and the conductive material 43 are uniformly deposited on the entire surface with a film thickness proportional to the number of cycles.

例えば、第１被膜４４としてＡｌ２Ｏ３を製膜する。もちろん、ＴｉＯ２、ＳｉＯ２、Ｔａ２Ｏ５等のように、１００℃以下で形成可能且つ絶縁性を持ったＡＬＤ膜が製膜可能であれば、他の金属酸化物のＡＬＤ膜を形成しても良い。 For example, Al 2 O 3 is formed as the first coating film 44. Of course, if an ALD film that can be formed at 100 ° C. or lower and has an insulating property such as TiO 2 , SiO 2 , Ta 2 O 5 or the like can be formed, an ALD film of another metal oxide is formed. May be.

そして、正極集電体４１をセル形状にカットする切断工程を行う。ここで、第１被膜４４の形成は、正極集電体４１をセル形状にカットした後に行っても良い。すなわち、真空乾燥工程の後に切断工程を行う。そして、当該切断工程の後に被膜形成工程を行う。これにより、正極集電体４１のカット面にも第１被膜４４を形成することができる。このため、筐体１０の内部に混入した金属異物に対する絶縁性や、正極集電体４１の金属バリ等の絶縁性を確保することができる。したがって、蓄電素子１の品質が向上する。以上のようにして、正極４０及び負極５０をそれぞれ形成する。   Then, a cutting step of cutting the positive electrode current collector 41 into a cell shape is performed. Here, the first coating film 44 may be formed after the positive electrode current collector 41 is cut into a cell shape. That is, the cutting step is performed after the vacuum drying step. Then, a film forming step is performed after the cutting step. Accordingly, the first coating film 44 can be formed on the cut surface of the positive electrode current collector 41. For this reason, it is possible to secure the insulating property against the foreign metal particles mixed in the housing 10 and the insulating property such as the metal burr of the positive electrode current collector 41. Therefore, the quality of the storage element 1 is improved. The positive electrode 40 and the negative electrode 50 are formed as described above.

続いて、セパレータ６０を用意し、セパレータ６０を正極４０と負極５０とで挟む電極組み付け工程を行う。すなわち、負極５０、セパレータ６０、正極４０、セパレータ６０、負極５０、・・・となるように各々を積層することで積層体７０を形成する。   Subsequently, a separator 60 is prepared, and an electrode assembly step of sandwiching the separator 60 between the positive electrode 40 and the negative electrode 50 is performed. That is, the laminated body 70 is formed by laminating the negative electrode 50, the separator 60, the positive electrode 40, the separator 60, the negative electrode 50, ...

また、複数の正極４０の各正極集電体４１の端部と正極端子２０の一端側とを接続する。同様に、複数の負極５０の各負極集電体５１の端部と負極端子３０の一端側とを接続する。   Further, the ends of the positive electrode collectors 41 of the plurality of positive electrodes 40 are connected to one end of the positive electrode terminal 20. Similarly, the ends of the negative electrode current collectors 51 of the plurality of negative electrodes 50 are connected to one end of the negative electrode terminal 30.

この後、筐体１０に積層体７０を組み付けるセル組み付け工程を行う。すなわち、セパレータ６０、正極４０、負極５０、正極端子２０の一部、及び負極端子３０の一部を収容室１８に収容する。ここで、筐体１０を構成する各ラミネートフィルム１１、１２の四辺の外周縁１５のうちの一辺が開口するように各ラミネートフィルム１１、１２を接合する。そして、減圧室で真空乾燥工程を行う。   After that, a cell assembling step of assembling the laminated body 70 to the housing 10 is performed. That is, the separator 60, the positive electrode 40, the negative electrode 50, part of the positive electrode terminal 20, and part of the negative electrode terminal 30 are housed in the housing chamber 18. Here, the laminated films 11 and 12 are joined so that one side of the outer peripheral edges 15 of the four sides of the laminated films 11 and 12 that form the housing 10 is open. Then, a vacuum drying process is performed in the decompression chamber.

さらに、各ラミネートフィルム１１、１２の開口部から電解液を注入する電解液注液工程を行う。最後に、各ラミネートフィルム１１、１２の開口部を封止する封止工程を行う。こうして、蓄電素子１が完成する。   Further, an electrolytic solution injecting step of injecting an electrolytic solution through the openings of the laminate films 11 and 12 is performed. Finally, a sealing step of sealing the openings of the laminated films 11 and 12 is performed. In this way, the storage element 1 is completed.

以上説明したように、本実施形態では、正極４０の表面の全体を覆う金属酸化物の第１被膜４４が設けられている。このような構成では、正極集電体４１と正極活物質４２との接触、正極集電体４１と導電材４３との接触、及び正極活物質４２と導電材４３との接触が維持された状態で正極４０の表面に第１被膜４４が形成されている。   As described above, in the present embodiment, the first coating film 44 of metal oxide that covers the entire surface of the positive electrode 40 is provided. In such a configuration, the contact between the positive electrode current collector 41 and the positive electrode active material 42, the contact between the positive electrode current collector 41 and the conductive material 43, and the contact between the positive electrode active material 42 and the conductive material 43 are maintained. Thus, the first coating film 44 is formed on the surface of the positive electrode 40.

このため、各接触の電気的な接続を確実に確保することができる。すなわち、正極活物質４２の電子伝導性を確保することができる。これに対し、正極活物質４２等が予め被膜に覆われたもので構成された正極４０では、当該被膜を介して正極活物質４２と正極集電体４１が接触したり、正極活物質４２と導電材４３が接触する。このため、当該被膜が電気的な接続を不十分にすると共に、抵抗成分となる。しかしながら、本実施形態に係る第１被膜４４は、正極集電体４１、正極活物質４２、及び導電材４３の電気的接続を阻害しないので、互いの電流パスにおける抵抗成分の増加を抑制することができる。   Therefore, the electrical connection of each contact can be reliably ensured. That is, the electron conductivity of the positive electrode active material 42 can be ensured. On the other hand, in the positive electrode 40 configured by covering the positive electrode active material 42 and the like in advance with the coating, the positive electrode active material 42 and the positive electrode current collector 41 contact each other through the coating, and the positive electrode active material 42 and The conductive material 43 contacts. Therefore, the coating film becomes insufficient in electrical connection and becomes a resistance component. However, since the first coating film 44 according to the present embodiment does not hinder the electrical connection between the positive electrode current collector 41, the positive electrode active material 42, and the conductive material 43, it suppresses an increase in the resistance component in the mutual current paths. You can

また、正極集電体４１、正極活物質４２、及び導電材４３が第１被膜４４に覆われているので、これらが電解液に接触しないようにすることができる。このため、正極集電体４１、正極活物質４２、及び導電材４３と電解液に含まれる電解質物質との反応における電解液分解物の生成を抑制することができる。したがって、蓄電素子１の電池性能を向上させることができる。負極５０についても正極４０と同様の構成により上記と同様の効果が得られる。   Further, since the positive electrode current collector 41, the positive electrode active material 42, and the conductive material 43 are covered with the first coating film 44, it is possible to prevent them from coming into contact with the electrolytic solution. Therefore, it is possible to suppress the generation of the electrolytic solution decomposition product in the reaction of the positive electrode current collector 41, the positive electrode active material 42, and the conductive material 43 with the electrolytic substance contained in the electrolytic solution. Therefore, the battery performance of the storage element 1 can be improved. With respect to the negative electrode 50 as well, the same effect as above can be obtained with the same configuration as the positive electrode 40.

発明者らは、第１被膜４４及び第２被膜５３の厚みと蓄電素子１の電池容量との関係を調べた。その結果を図５及び図６に示す。   The inventors investigated the relationship between the thickness of the first coating 44 and the second coating 53 and the battery capacity of the storage element 1. The results are shown in FIGS. 5 and 6.

まず、蓄電素子１の電池容量を０％から１００％まで上下させると、正極４０の表面の電位が上がる。このため、第１被膜４４が形成されていないものは正極４０と電解液とが反応しやすくなるので、電解液が分解して電池容量が低下する。そこで、発明者らは、蓄電素子１の１回の充放電を１サイクルとして、サイクル数の増加に対する蓄電素子１の容量維持率の変化を調べた。   First, when the battery capacity of the storage element 1 is increased or decreased from 0% to 100%, the potential on the surface of the positive electrode 40 rises. Therefore, in the case where the first coating film 44 is not formed, the positive electrode 40 and the electrolytic solution are likely to react with each other, and the electrolytic solution is decomposed to reduce the battery capacity. Therefore, the inventors examined the change in the capacity retention ratio of the electricity storage device 1 with respect to the increase in the number of cycles, with one charge / discharge of the electricity storage device 1 as one cycle.

ここで、調査対象の正極活物質４２をＬｉＮｉ０．５Ｍｎ１．５Ｏ４とし、負極活物質５２を炭素（Ｃ）とした。正極４０では、正極活物質４２、導電材４３、正極活物質４２及び導電材４３を正極端子４１に保持するバインダの比率を８０：１０：１０として混合した。また、負極５０では、炭素（Ｃ）とバインダとの比率を９０：１０として混合した。 Here, the positive electrode active material 42 to be investigated was LiNi 0.5 Mn 1.5 O 4 and the negative electrode active material 52 was carbon (C). In the positive electrode 40, the positive electrode active material 42, the conductive material 43, and the binder that holds the positive electrode active material 42 and the conductive material 43 in the positive electrode terminal 41 were mixed at a ratio of 80:10:10. In the negative electrode 50, carbon (C) and the binder were mixed at a ratio of 90:10.

図５に示されるように、蓄電素子１に各被膜４４、５３が設けられていないものは、サイクル数の増加に伴って容量維持率が減少した。これに対し、蓄電素子１に各被膜４４、５３が設けられたものでは、サイクル数の増加に関わらず容量維持率は維持された。   As shown in FIG. 5, in the electricity storage device 1 in which the coating films 44 and 53 were not provided, the capacity retention ratio decreased as the number of cycles increased. On the other hand, in the storage element 1 provided with the coatings 44 and 53, the capacity retention rate was maintained regardless of the increase in the number of cycles.

また、図６は、各被膜４４、５３の有無による蓄電素子１の放電カーブを示している。各被膜４４、５３の有無により、活物質あたりの容量に差があることが明らかとなった。活物質あたりの容量に差の主要因として、放電直後の電圧低下が大きく起因している。被膜無しのものは電極表面に電解液の分解物が形成されたことに起因する抵抗増加が発生する。これに対し、電極表面に各被膜４４、５３が形成することで電解液の分解を抑制でき、電解液分解による抵抗上昇を抑制できたと考えられる。   Further, FIG. 6 shows a discharge curve of the storage element 1 with and without the coatings 44 and 53. It was clarified that the capacities per active material differ depending on the presence or absence of the coatings 44 and 53. The main cause of the difference in the capacity per active material is the voltage drop immediately after discharge. In the case of no coating, the resistance increases due to the decomposition product of the electrolytic solution formed on the electrode surface. On the other hand, it is considered that the formation of the coating films 44 and 53 on the electrode surface can suppress the decomposition of the electrolytic solution and suppress the increase in resistance due to the decomposition of the electrolytic solution.

以上の各結果から、各被膜４４、５３によって蓄電素子１の電池性能が向上したことがわかる。   From the above results, it can be seen that the coating films 44 and 53 improve the battery performance of the electricity storage device 1.

特に、正極活物質４２の作動電位が４．０Ｖ以上のものだと特に効果が大きい。例えば、ＬｉＮｉ０．５Ｍｎ１．５Ｏ４やＬｉＭｎＰＯ４やＬｉＣｏＰＯ４の少なくとも１種類の物質を含むというように、正極活物質４２が複数の物質で構成された蓄電素子１では電解液の分解が促進されやすいので、各被膜４４、５３の形成の効果が大きい。また、ＬｉＭｎＰＯ４の元素の一部が置換されたＬｉＦｅｘＭｎ１−ｘＰＯ４というように、元素が一部置換された正極活物質４２を備えた蓄電素子１についても同様の効果が得られる。 In particular, when the positive electrode active material 42 has an operating potential of 4.0 V or higher, the effect is particularly great. For example, in the electricity storage device 1 in which the positive electrode active material 42 is composed of a plurality of substances, such as containing at least one kind of substance of LiNi 0.5 Mn 1.5 O 4 , LiMnPO 4, and LiCoPO 4 , decomposition of the electrolytic solution is performed. Is easily promoted, the effect of forming the coating films 44 and 53 is great. Also, as referred LiFe x Mn 1-x PO 4 where part of the elements is substituted in LiMnPO 4, the same effect can be obtained for the electricity storage device 1 element with a positive electrode active material 42 which is partially substituted .

（第２実施形態）
本実施形態では、第１実施形態と異なる部分について説明する。図７に示されるように、蓄電素子１は、第３被膜７１を備えている。第３被膜７１は、セパレータ６０が正極４０と負極５０とに挟まれた状態での、セパレータ６０、正極４０、及び負極５０によって構成された表面の全体を覆う金属酸化物の膜である。 (Second embodiment)
In the present embodiment, parts different from the first embodiment will be described. As shown in FIG. 7, the electricity storage device 1 includes a third coating 71. The third coating 71 is a metal oxide film that covers the entire surface of the separator 60, the positive electrode 40, and the negative electrode 50 when the separator 60 is sandwiched between the positive electrode 40 and the negative electrode 50.

すなわち、第３被膜７１は、セパレータ６０のうち正極４０及び負極５０と接触する部位を除いた表面にも形成されている。したがって、正極４０及び負極５０は第３被膜７１を介してではなく、セパレータ６０に直接接触している。また、第３被膜７１は、正極４０、負極５０、及びセパレータ６０の全てに同一の金属酸化物で形成されている。   That is, the third coating 71 is also formed on the surface of the separator 60 excluding the portions in contact with the positive electrode 40 and the negative electrode 50. Therefore, the positive electrode 40 and the negative electrode 50 are in direct contact with the separator 60, not via the third coating film 71. Further, the third coating 71 is formed of the same metal oxide on all of the positive electrode 40, the negative electrode 50, and the separator 60.

次に、本実施形態に係る蓄電素子１の製造方法について、図８を参照して説明する。本実施形態では、セパレータ６０を正極４０と負極５０とで挟む電極組み付け工程の後に、第３被膜７１を形成する製膜工程を行う。すなわち、積層体７０の表面全体に第３被膜７１を製膜する。製膜は、チャンバ内に積層体７０が複数配置された状態で行われても良い。   Next, a method for manufacturing the electricity storage device 1 according to the present embodiment will be described with reference to FIG. In the present embodiment, a film forming step of forming the third coating film 71 is performed after the electrode assembly step of sandwiching the separator 60 between the positive electrode 40 and the negative electrode 50. That is, the third coating 71 is formed on the entire surface of the laminated body 70. The film formation may be performed in a state where a plurality of laminated bodies 70 are arranged in the chamber.

そして、チャンバ内温度を６０℃に設定し、原料であるＴＭＡを２０℃、水を４０℃として、金属酸化物としてＡｌ２Ｏ３の第３被膜７１を製膜する。製膜条件としては、ＴＭＡガス輸送を１ｓｅｃ、パージを３ｓｅｃとし、Ｈ２Ｏガス輸送を１ｓｅｃ、パージを３ｓｅｃとして製膜を実施した。発明者らは、第３被膜７１が積層体７０の全面に均一に着膜することを確認した。 Then, the temperature inside the chamber is set to 60 ° C., the raw material TMA is set to 20 ° C., the water is set to 40 ° C., and the third coating film 71 of Al 2 O 3 is formed as a metal oxide. Film forming conditions were as follows: TMA gas transportation was 1 sec, purging was 3 sec, H 2 O gas transportation was 1 sec, and purging was 3 sec. The inventors have confirmed that the third coating film 71 is uniformly deposited on the entire surface of the laminated body 70.

なお、積層体７０の最表面は第３被膜７１の溶解を考慮し、例えばＡｌ２Ｏ３とＴｉＯ２との積層構造とすることで第３被膜７１の溶解を防止することが可能である。また、製膜の温度が低いため、Ｈ２Ｏ等のガスの粘性が高いものを考慮して各製膜条件（特にパージ時間）を十分大きく設定することが好ましい。 Note that the outermost surface of the laminated body 70 can prevent the dissolution of the third coating film 71 by considering the dissolution of the third coating film 71 and having a laminated structure of, for example, Al 2 O 3 and TiO 2 . Further, since the film forming temperature is low, it is preferable to set each film forming condition (particularly, the purge time) sufficiently large in consideration of a gas such as H 2 O having a high viscosity.

上記のように第３被膜７１を形成した後、上述のセル組み付け工程以降の各工程を行う。こうして、本実施形態に係る蓄電素子１が完成する。   After forming the third coating 71 as described above, the respective steps after the cell assembling step described above are performed. Thus, the electricity storage device 1 according to the present embodiment is completed.

以上のように、第３被膜７１を成膜する工程を電極組み付け工程の後にすることでセパレータ６０も含んだ積層体７０の全体に第３被膜７１が設けられた構成を提供することができる。なお、本実施形態の記載と特許請求の範囲の記載との対応関係については、第３被膜７１が特許請求の範囲の「被膜」に対応する。   As described above, by performing the step of forming the third coating film 71 after the electrode assembly step, it is possible to provide a configuration in which the third coating film 71 is provided on the entire laminated body 70 including the separator 60. Regarding the correspondence relationship between the description of the present embodiment and the description of the claims, the third coating 71 corresponds to the “coating” of the claims.

（第３実施形態）
本実施形態では、第２２実施形態と異なる部分について説明する。本実施形態では、積層体７０が収容された収容室１８内にも第３被膜７１が形成されている。すなわち、第３被膜７１は、収容室１８のうち、当該収容室１８の壁面１９、セパレータ６０、正極４０、負極５０、正極端子２０の一部、及び負極端子３０の一部によって構成された表面の全体を覆っている。 (Third Embodiment)
In this embodiment, parts different from the 22nd embodiment will be described. In the present embodiment, the third coating 71 is also formed inside the storage chamber 18 in which the stacked body 70 is stored. That is, the third coating 71 is a surface of the housing chamber 18 that is formed by the wall surface 19 of the housing chamber 18, the separator 60, the positive electrode 40, the negative electrode 50, a part of the positive electrode terminal 20, and a part of the negative electrode terminal 30. Covers the whole.

具体的には、図９に示されるように、第３被膜７１は、正極端子２０の一部である一端側、収容室１８の壁面１９、当該壁面１９を構成するタブフィルム１６の上に製膜されている。したがって、第３被膜７１は、収容室１８の壁面１９、セパレータ６０、正極４０、負極５０、正極端子２０の一部、及び負極端子３０の一部の全てに同一の金属酸化物で形成されている。   Specifically, as shown in FIG. 9, the third coating 71 is formed on one end side which is a part of the positive electrode terminal 20, the wall surface 19 of the housing chamber 18, and the tab film 16 which constitutes the wall surface 19. It is a film. Therefore, the third coating 71 is formed of the same metal oxide on all of the wall surface 19 of the housing chamber 18, the separator 60, the positive electrode 40, the negative electrode 50, a part of the positive electrode terminal 20, and a part of the negative electrode terminal 30. There is.

なお、図示されていない負極端子３０側についても同様に第３被膜７１が負極端子３０の一部である一端側、収容室１８の壁面１９、当該壁面１９を構成するタブフィルム１７の上に製膜されている。   In addition, on the negative electrode terminal 30 side not shown, similarly, the third coating 71 is formed on one end side which is a part of the negative electrode terminal 30, the wall surface 19 of the housing chamber 18, and the tab film 17 constituting the wall surface 19. It is a film.

次に、本実施形態に係る蓄電素子１の製造方法について、図１０を参照して説明する。本実施形態では、まず、上述のように筐体１０に積層体７０を組み付けるセル組み付け工程までを行う。すなわち、積層体７０、正極端子２０の一部、及び負極端子３０の一部を収容室１８に収容する。本工程では、筐体１０を構成する各ラミネートフィルム１１、１２の四辺の外周縁１５のうちの一辺を開口させている。そして、真空乾燥工程を行う。   Next, a method for manufacturing the electricity storage device 1 according to the present embodiment will be described with reference to FIG. 10. In this embodiment, first, a cell assembling step of assembling the laminated body 70 to the housing 10 as described above is performed. That is, the stacked body 70, part of the positive electrode terminal 20, and part of the negative electrode terminal 30 are housed in the housing chamber 18. In this step, one side of the outer peripheral edges 15 of the four sides of each of the laminate films 11 and 12 forming the housing 10 is opened. Then, a vacuum drying process is performed.

この後、第３被膜７１の製膜の前に、正極端子２０及び負極端子３０の各他端側や筐体１０の外表面にマスクを形成しておく。これにより、正極端子２０及び負極端子３０の各他端側や筐体１０の外表面への着膜を防止する。   After that, before forming the third coating 71, a mask is formed on the other end sides of the positive electrode terminal 20 and the negative electrode terminal 30 and on the outer surface of the housing 10. This prevents film formation on the other end sides of the positive electrode terminal 20 and the negative electrode terminal 30 and on the outer surface of the housing 10.

そして、各ラミネートフィルム１１、１２の開口部から収容室１８に原料ガスを流し込む製膜工程を行う。製膜の条件は第２実施形態と同じである。これにより、収容室１８の壁面１９、セパレータ６０、正極４０、負極５０、正極端子２０の一部、及び負極端子３０の一部によって構成された表面の全体に、金属酸化物としてＡｌ２Ｏ３の第３被膜７１を形成する。 Then, a film forming process is performed in which the source gas is flown into the accommodation chamber 18 through the openings of the laminate films 11 and 12. The conditions for film formation are the same as in the second embodiment. As a result, the entire surface formed by the wall surface 19 of the storage chamber 18, the separator 60, the positive electrode 40, the negative electrode 50, a part of the positive electrode terminal 20, and a part of the negative electrode terminal 30 is Al 2 O 3 as a metal oxide. To form the third coating 71.

なお、第３被膜７１の製膜は、チャンバ内に複数の筐体１０が配置された状態で行われても良い。また、第２実施形態と同様に、積層体７０の最表面をＡｌ２Ｏ３とＴｉＯ２との積層構造としても良い。 The film formation of the third coating 71 may be performed in a state where the plurality of housings 10 are arranged in the chamber. Further, similarly to the second embodiment, the outermost surface of the laminated body 70 may have a laminated structure of Al 2 O 3 and TiO 2 .

上記のように第３被膜７１を形成した後、上述の電解液注液工程以降の各工程を行う。こうして、本実施形態に係る蓄電素子１が完成する。以上のように、第３被膜７１を成膜する工程をセル組み付け工程後の真空乾燥工程の後に形成することで、筐体１０の収容室１８の壁面１９にも第３被膜７１が設けられた構成を提供することができる。   After forming the third coating 71 as described above, the above-described electrolytic solution injection step and the subsequent steps are performed. Thus, the electricity storage device 1 according to the present embodiment is completed. As described above, the step of forming the third coating 71 is formed after the vacuum drying step after the cell assembling step, so that the wall 19 of the housing chamber 18 of the housing 10 is also provided with the third coating 71. A configuration can be provided.

また、リチウム電池では電解液の塩として、ヘキサフルオロリン酸リチウム（ＬｉＰＦ６）、テトラフルオロホウ酸リチウム（ＬｉＢＦ４）を用いることが多いが、正極集電箔のアルミニウムに保護膜を作らないＬｉ塩、具体的にはリチウムビス（トリフルオロメタンスルホニル）イミド（ＬｉＴＦＳＩ）、リチウムビス（フルオロスルホニル）イミド（ＬｉＦＳＩ）等についても、金属酸化物の第３被膜７１を蓄電素子１の筐体１０内に製膜することで、アルミニウムと電解液との接触を抑制できるため、同様の効果を得ることができる。 Further, in a lithium battery, lithium hexafluorophosphate (LiPF 6 ) and lithium tetrafluoroborate (LiBF 4 ) are often used as the salt of the electrolytic solution, but a protective film is not formed on the aluminum of the positive electrode current collector foil. For salts, specifically, lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium bis (fluorosulfonyl) imide (LiFSI), etc., the third coating 71 of metal oxide is provided in the housing 10 of the electricity storage device 1. By forming the film, contact between aluminum and the electrolytic solution can be suppressed, and thus the same effect can be obtained.

なお、本実施形態の記載と特許請求の範囲の記載との対応関係については、第３被膜７１が特許請求の範囲の「被膜」に対応する。   Regarding the correspondence relationship between the description of the present embodiment and the description of the claims, the third coating 71 corresponds to the “coating” of the claims.

（他の実施形態）
上記各実施形態で示された蓄電素子１の構成は一例であり、上記で示した構成に限定されることなく、本発明を実現できる他の構成とすることもできる。例えば、蓄電素子１の形態はラミネート型に限られない。例えば、蓄電素子１はコイン型、円筒型、角型等の種々の形状でも良い。 (Other embodiments)
The configuration of the electricity storage device 1 shown in each of the above-described embodiments is an example, and the present invention is not limited to the configuration shown above, and may have another configuration that can realize the present invention. For example, the form of the electricity storage device 1 is not limited to the laminate type. For example, the electricity storage device 1 may have various shapes such as a coin shape, a cylinder shape, and a square shape.

また、上記各実施形態では、正極４０に正極活物質４２、導電材４３、バインダ等を用いた内容を説明したが、正極活物質４２を直接製膜するような電池においても上記と同様の効果が得られる。   In addition, in each of the above-described embodiments, the content in which the positive electrode active material 42, the conductive material 43, the binder, and the like are used for the positive electrode 40 has been described. Is obtained.

さらに、ＬｉＦＳＩを電解液の塩として用いた場合も同様の検討を行った結果、製膜無しと比較して、各被膜４４、５３、７１を製膜したものは高い電池性能を維持することが明らかとなった。   Furthermore, when LiFSI was used as the salt of the electrolytic solution, the same examination was carried out. As a result, the films with the films 44, 53 and 71 formed can maintain high battery performance as compared with the case without film formation. It became clear.

１０ 筐体
１８ 収容室
１９ 壁面
２０、３０ 端子
４０ 正極
４２ 正極活物質
４４、５３、７１ 被膜
５０ 負極
５２ 負極活物質
６０ セパレータ 10 Casing 18 Storage Chamber 19 Wall Surface 20, 30 Terminal 40 Positive Electrode 42 Positive Electrode Active Material 44, 53, 71 Coating 50 Negative Electrode 52 Negative Electrode Active Material 60 Separator

Claims (8)

金属イオンを吸蔵放出可能な正極活物質（４２）を主成分とする正極（４０）と、
前記金属イオンを吸蔵放出可能な負極活物質（５２）を主成分とする負極（５０）と、
前記正極と前記負極とに挟まれており、前記金属イオンの伝導性を有すると共に、前記正極と前記負極とを電気的に絶縁分離するセパレータ（６０）と、
前記正極に接続された正極端子（２０）と、
前記負極に接続された負極端子（３０）と、
前記セパレータが前記正極と前記負極とに挟まれた状態で、前記セパレータ、前記正極、前記負極、前記正極端子の一部、及び前記負極端子の一部を収容室（１８）に収容する筐体（１０）と、
前記収容室のうち、当該収容室の壁面（１９）、前記セパレータ、前記正極、前記負極、前記正極端子の一部、及び前記負極端子の一部によって構成された表面の全体を覆う金属酸化物の被膜（７１）と、
を備えている蓄電素子。 A positive electrode (40) containing, as a main component, a positive electrode active material (42) capable of inserting and extracting metal ions;
A negative electrode (50) containing as a main component a negative electrode active material (52) capable of inserting and extracting the metal ions;
A separator (60) sandwiched between the positive electrode and the negative electrode, having conductivity of the metal ions, and electrically insulating and separating the positive electrode and the negative electrode;
A positive electrode terminal (20) connected to the positive electrode,
A negative electrode terminal (30) connected to the negative electrode,
A housing for accommodating the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal in the accommodating chamber (18) while the separator is sandwiched between the positive electrode and the negative electrode. (10),
A metal oxide covering the entire surface of the storage chamber, which is constituted by the wall surface (19) of the storage chamber, the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal. Film (71) of
An electric storage device including. 前記金属酸化物は、Ａｌ、Ｔｉ、Ｓｉのうちの少なくとも１つを含む酸化物である請求項１に記載の蓄電素子。 The electricity storage device according to claim 1, wherein the metal oxide is an oxide containing at least one of Al, Ti, and Si. 前記金属酸化物は、少なくともＡｌを含むと共に、Ｔｉ及びＳｉのうちの少なくとも１つを含む酸化物である請求項１に記載の蓄電素子。 The electricity storage device according to claim 1, wherein the metal oxide is an oxide containing at least Al and at least one of Ti and Si. 前記金属酸化物は、Ｌｉを含む酸化物である請求項１ないし３のいずれか１つに記載の蓄電素子。 The metal oxide, the electric storage device according to to any one of 3 claims 1 to an oxide containing Li. 金属イオンを吸蔵放出可能な正極活物質（４２）を主成分とする正極（４０）を用意する工程と、
前記金属イオンを吸蔵放出可能な負極活物質（５２）を主成分とする負極（５０）を用意する工程と、
前記金属イオンの伝導性を有すると共に、前記正極と前記負極とを電気的に絶縁分離するセパレータ（６０）を用意し、前記セパレータを前記正極と前記負極とで挟む工程と、
前記正極に正極端子（２０）を接続する工程と、
前記負極に負極端子（３０）を接続する工程と、
収容室（１８）を有する筐体（１０）を用意し、前記セパレータ、前記正極、前記負極、前記正極端子の一部、及び前記負極端子の一部を前記収容室に収容する工程と、
前記収容室のうち、当該収容室の壁面（１９）、前記セパレータ、前記正極、前記負極、前記正極端子の一部、及び前記負極端子の一部によって構成された表面の全体を覆う金属酸化物の被膜（７１）を形成する工程と、
を含んでいる蓄電素子の製造方法。 A step of preparing a positive electrode (40) whose main component is a positive electrode active material (42) capable of inserting and extracting metal ions;
A step of preparing a negative electrode (50) containing a negative electrode active material (52) capable of inserting and extracting metal ions as a main component;
A step of preparing a separator (60) having electrical conductivity of the metal ions and electrically insulating and separating the positive electrode and the negative electrode, and sandwiching the separator between the positive electrode and the negative electrode,
Connecting a positive electrode terminal (20) to the positive electrode,
Connecting a negative electrode terminal (30) to the negative electrode;
Preparing a casing (10) having a storage chamber (18) and storing the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal in the storage chamber;
A metal oxide covering the entire surface of the storage chamber, which is constituted by the wall surface (19) of the storage chamber, the separator, the positive electrode, the negative electrode, a part of the positive electrode terminal, and a part of the negative electrode terminal. Forming a film (71) of
A method for manufacturing an electricity storage device including: 前記被膜を形成する工程では、前記金属酸化物としてＡｌ、Ｔｉ、Ｓｉの少なくとも１つを含む酸化物の被膜を形成する請求項５に記載の蓄電素子の製造方法。 The method of manufacturing an electricity storage device according to claim 5 , wherein in the step of forming the coating film, a coating film of an oxide containing at least one of Al, Ti, and Si is formed as the metal oxide. 前記被膜を形成する工程では、前記金属酸化物として少なくともＡｌを含むと共にＴｉ、Ｓｉの少なくとも１つを含む酸化物の被膜を形成する請求項５に記載の蓄電素子の製造方法。 The method for manufacturing an electricity storage device according to claim 5 , wherein, in the step of forming the coating film, a coating film of an oxide containing at least Al as the metal oxide and containing at least one of Ti and Si is formed. 前記被膜を形成する工程では、前記金属酸化物として、Ｌｉを含む酸化物の被膜を形成する請求項５ないし７のいずれか１つに記載の蓄電素子の製造方法。 In the step of forming the coating film, as the metal oxide, a manufacturing method of a power storage device according to any one of claims 5 to 7 to form a coating of oxide containing Li.
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