JP6316091B2 - Lithium ion secondary battery - Google Patents

Lithium ion secondary battery Download PDF

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JP6316091B2
JP6316091B2 JP2014103022A JP2014103022A JP6316091B2 JP 6316091 B2 JP6316091 B2 JP 6316091B2 JP 2014103022 A JP2014103022 A JP 2014103022A JP 2014103022 A JP2014103022 A JP 2014103022A JP 6316091 B2 JP6316091 B2 JP 6316091B2
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JP2015220097A (en
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佳太郎 大槻
佳太郎 大槻
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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
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Description

本発明は、リチウムイオン二次電池に関するものである。   The present invention relates to a lithium ion secondary battery.

近年、エレクトロニクス技術の発達はめざましく、携帯電子機器の小型軽量化、薄型化、多機能化が図られている。それに伴い、電子機器の電源となる電池に対し、小型軽量化、薄型化、信頼性の向上が強く望まれており、電解質が固体電解質から成る全固体型のリチウムイオン二次電池が注目されている。   In recent years, the development of electronic technology has been remarkable, and portable electronic devices have been made smaller, lighter, thinner, and multifunctional. As a result, there is a strong demand for smaller, lighter, thinner, and more reliable batteries that serve as power sources for electronic devices, and all-solid-state lithium-ion secondary batteries that use a solid electrolyte as the electrolyte are attracting attention. Yes.

一般に、全固体型のリチウムイオン二次電池は、薄膜型とバルク型の２種類に分類される。薄膜型は、ＰＶＤ法やゾルゲル法などの薄膜技術により、またバルク型は活物質や粒界抵抗の低い硫化物系固体電解質の粉末成型により作製される。しかしながら、薄膜型は活物質層を厚くすることや高積層化することが困難であるため容量が小さく、また製造コストが高いという問題がある。一方、バルク型には硫化物系固体電解質が用いられており、これが水と反応した際に硫化水素が発生するため、露点の管理されたグローブボックス内で電池を作製する必要がある。また、シート化するのが困難なため固体電解質層の薄層化や電池の高積層化が課題となっている。   In general, all solid-state lithium ion secondary batteries are classified into two types: thin film type and bulk type. The thin film type is produced by thin film technology such as PVD method or sol-gel method, and the bulk type is produced by powder molding of an active material or a sulfide-based solid electrolyte having low grain boundary resistance. However, since it is difficult to increase the thickness of the active material layer or to increase the number of layers, the thin film type has a problem that the capacity is small and the manufacturing cost is high. On the other hand, a sulfide-type solid electrolyte is used for the bulk type, and hydrogen sulfide is generated when it reacts with water. Therefore, it is necessary to produce a battery in a glove box in which the dew point is controlled. In addition, since it is difficult to form a sheet, it is a problem to reduce the thickness of the solid electrolyte layer and to increase the battery stack.

このような問題を鑑みて、特許文献１において、空気中で安定な酸化物系固体電解質を用い、各部材をシート化し、積層した後、同時に焼成するという、工業的に採用し得る量産可能な製造方法により作製される全固体電池が提唱されている。しかしながら、異種の材料を同時に焼成することから正極層及び負極層と固体電解質層とを強固に接合することが困難であった。
そこで、特許文献２では、正極層及び／または負極層と固体電解質層との界面に、活物質又は電解質として機能する物質からなる中間層を有する固体電解質電池を開示している。また、特許文献３では、少なくとも一方の電極と固体電解質との界面に少なくとも電極材料の一元素と固体電解質の一元素を含む化合物を構成する領域を形成していることを開示している。 In view of such a problem, in Patent Document 1, an oxide-based solid electrolyte that is stable in the air is used, and each member is formed into a sheet, laminated, and then fired at the same time. An all solid state battery produced by a manufacturing method has been proposed. However, since different materials are fired at the same time, it has been difficult to firmly bond the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.
Therefore, Patent Document 2 discloses a solid electrolyte battery having an intermediate layer made of a substance that functions as an active material or an electrolyte at the interface between the positive electrode layer and / or the negative electrode layer and the solid electrolyte layer. Patent Document 3 discloses that a region constituting a compound containing at least one element of an electrode material and one element of a solid electrolyte is formed at the interface between at least one electrode and the solid electrolyte.

特再０７−１３５７９０号公報Japanese Patent Publication No. 07-135790 国際公報第２００８／１４３０２７号International Publication No. 2008/143027 特開２００４−２８１３１６号公報JP 2004-281316 A

しかしながら、上述した固体電解質電池では、活物質層の活物質を用いて中間層を形成することにより活物質量が減少し、十分な電池容量を得ることができなかった。   However, in the solid electrolyte battery described above, the amount of the active material is reduced by forming the intermediate layer using the active material of the active material layer, and a sufficient battery capacity cannot be obtained.

そこで本発明は上記課題を解決するために成されたものであり、固体電解質を用いたリチウムイオン二次電池の容量低下を抑制しつつ、高い放電レート特性を目的とする。   Accordingly, the present invention has been made to solve the above-described problems, and aims at high discharge rate characteristics while suppressing a decrease in capacity of a lithium ion secondary battery using a solid electrolyte.

上記課題を解決するために、本発明におけるリチウムイオン二次電池は、正極集電層体と正極集電体層上に配置された正極活物質層からなる正極層と、負極集電体層と負極集電体層上に配置された負極活物質層からなる負極層と、正極層と負極層とが固体電解質層を介して積層されたリチウムイオン二次電池において、正極活物質層は正極活物質を含み、負極活物質層は負極活物質を含み、固体電解質層は固体電解質を含み、正極活物質層又は負極活物質層と固体電解質層とが接する少なくとも１つの接触面において、正極活物質又は負極活物質を構成する元素の少なくとも一部と固体電解質を構成する元素の少なくとも一部からなる中間化合物を、正極活物質又は負極活物質と固体電解質が接触する接触面に有し、接触面は、正極層又は負極層と固体電解質層が直接接合する領域Ｌ１と、正極層又は負極層と固体電解質層が中間化合物を介して接合する領域Ｌ２を持ち、前記Ｌ１とＬ２の関係がＬ１＞Ｌ２かつＬ２＞０であることを特徴とする。   In order to solve the above-described problems, a lithium ion secondary battery according to the present invention includes a positive electrode current collector layer, a positive electrode layer composed of a positive electrode active material layer disposed on the positive electrode current collector layer, a negative electrode current collector layer, In a lithium ion secondary battery in which a negative electrode layer composed of a negative electrode active material layer disposed on a negative electrode current collector layer and a positive electrode layer and a negative electrode layer are laminated via a solid electrolyte layer, the positive electrode active material layer is a positive electrode active material layer. A negative electrode active material layer containing a negative electrode active material, a solid electrolyte layer containing a solid electrolyte, and at least one contact surface where the positive electrode active material layer or the negative electrode active material layer and the solid electrolyte layer are in contact with each other, Or having an intermediate compound comprising at least a part of the elements constituting the negative electrode active material and at least a part of the elements constituting the solid electrolyte on the contact surface where the positive electrode active material or the negative electrode active material and the solid electrolyte are in contact, Is positive layer or negative A region L1 where the layer and the solid electrolyte layer are directly joined, and a region L2 where the positive electrode layer or the negative electrode layer and the solid electrolyte layer are joined via an intermediate compound, and the relationship between L1 and L2 is L1> L2 and L2> 0 It is characterized by being.

本発明を用いることにより、リチウムイオン二次電池の容量低下を抑制しつつ、高い放電レート特性を得ることができる。
このメカニズムについては定かではないが、以下のようなメカニズムであると考えられる。
すなわち、正極活物質層又は負極活物質層を構成する元素の少なくとも一部と固体電解質層を構成する元素の少なくとも一部からなる中間化合物が接触面に存在することにより、正極層又は負極層と固体電解質層間における元素の濃度勾配が緩和されることによりイオンの移動がスムーズになるためと考えられる。また、前記領域Ｌ１とＬ２の関係がＬ１＞Ｌ２かつＬ２＞０である場合、正極層又は負極層の活物質と固体電解質の減少を抑制されるためこれを用いたリチウムイオン二次電池の容量低下が抑制され、高い放電レート特性が得られるものと考えられる。 By using the present invention, it is possible to obtain high discharge rate characteristics while suppressing a decrease in capacity of the lithium ion secondary battery.
Although this mechanism is not clear, it is considered that it is as follows.
That is, an intermediate compound composed of at least a part of the elements constituting the positive electrode active material layer or the negative electrode active material layer and at least a part of the elements constituting the solid electrolyte layer is present on the contact surface. This is thought to be due to the smooth movement of ions due to the relaxation of the element concentration gradient between the solid electrolyte layers. Further, when the relationship between the regions L1 and L2 is L1> L2 and L2> 0, the reduction of the active material and the solid electrolyte in the positive electrode layer or the negative electrode layer is suppressed, so that the capacity of the lithium ion secondary battery using this It is considered that the decrease is suppressed and a high discharge rate characteristic is obtained.

上記発明においては、前記中間化合物が金属リン酸塩、金属ピロリン酸塩、金属バナジン酸塩の少なくとも１つからなる化合物であることが好ましい。   In the said invention, it is preferable that the said intermediate compound is a compound which consists of at least 1 of a metal phosphate, a metal pyrophosphate, and a metal vanadate.

本発明によれば、これを用いたリチウムイオン二次電池の容量低下を抑制しつつ、熱安定性の低下を抑制することができる。これらの中間化合物は酸素の放出温度が高いため、熱安定性を低下することなく高温における放電レート特性を向上することが出来る。   ADVANTAGE OF THE INVENTION According to this invention, the fall of thermal stability can be suppressed, suppressing the capacity | capacitance fall of the lithium ion secondary battery using this. Since these intermediate compounds have a high oxygen release temperature, discharge rate characteristics at high temperatures can be improved without deteriorating thermal stability.

上記本発明においては、正極活物質又は負極活物質のいずれかがリン酸バナジウムリチウムを含むことが好ましい。   In the present invention, either the positive electrode active material or the negative electrode active material preferably contains lithium vanadium phosphate.

本発明によれば、これらの組成の正極活物質又は負極活物質を用いることにより、リチウムイオン二次電池の熱安定性が更に向上する。これは、組成元素のＰ，Ｖが熱安定性の高い金属リン酸塩、金属ピロリン酸塩、金属バナジン酸塩からなる中間化合物を生成するためと考えられる。   According to the present invention, the thermal stability of the lithium ion secondary battery is further improved by using the positive electrode active material or the negative electrode active material having these compositions. This is presumably because P and V of the composition elements generate intermediate compounds composed of metal phosphate, metal pyrophosphate, and metal vanadate having high thermal stability.

上記本発明においては、正極活物質及び負極活物質は共にリン酸バナジウムリチウムからなることが好ましい。   In the present invention, both the positive electrode active material and the negative electrode active material are preferably made of lithium vanadium phosphate.

本発明によれば、正極活物質及び負極活物質にこれらの組成の活物質を用いることにより、リチウムイオン二次電池の熱安定性が更に向上する。これは、正極層と固体電解質層間、負極層と固体電解質間のそれぞれに熱安定性の高い金属リン酸塩、金属ピロリン酸塩、金属バナジン酸塩からなる中間化合物を生成するためと考えられる。   According to the present invention, the thermal stability of the lithium ion secondary battery is further improved by using active materials having these compositions for the positive electrode active material and the negative electrode active material. This is considered to generate intermediate compounds composed of metal phosphate, metal pyrophosphate, and metal vanadate having high thermal stability between the positive electrode layer and the solid electrolyte layer and between the negative electrode layer and the solid electrolyte.

上記本発明においては、固体電解質が一般式Ｌｉ１＋ｘＡｌｘＴｉ２−ｘ（ＰＯ４）３（０≦ｘ≦０．６）で表される化合物であることが好ましい。 In the present invention, the solid electrolyte is preferably a compound represented by the general formula Li 1 + x Al x Ti 2-x (PO 4 ) 3 (0 ≦ x ≦ 0.6).

本発明によれば、上記した固体電解質材料を用いることにより、これを用いたリチウムイオン二次電池の放電レート特性が更に向上することができる。   According to the present invention, by using the above-described solid electrolyte material, the discharge rate characteristics of a lithium ion secondary battery using the material can be further improved.

また、上記発明においては、正極集電体層及び負極集電体層がＣｕを含むことが好ましい。   Moreover, in the said invention, it is preferable that a positive electrode collector layer and a negative electrode collector layer contain Cu.

本発明によれば、集電体層にＣｕを用いることにより、これを用いたリチウムイオン二次電池の放電レート特性が向上する。これは、正極集電体層及び負極集電体層を構成する材料と正極活物質又は負極活物質又は固体電解質が反応することがないため副反応による容量低下を抑制することができる。   According to the present invention, by using Cu for the current collector layer, the discharge rate characteristics of a lithium ion secondary battery using the current collector layer are improved. This is because the materials constituting the positive electrode current collector layer and the negative electrode current collector layer do not react with the positive electrode active material, the negative electrode active material, or the solid electrolyte, so that a decrease in capacity due to a side reaction can be suppressed.

本発明によれば、容量低下を抑制しつつ、高い放電レート特性を有するリチウムイオン二次電池を提供することができる。   ADVANTAGE OF THE INVENTION According to this invention, the lithium ion secondary battery which has a high discharge rate characteristic can be provided, suppressing a capacity | capacitance fall.

図１は、リチウムイオン二次電池の概念的構造を示す断面図である。FIG. 1 is a cross-sectional view showing a conceptual structure of a lithium ion secondary battery.

以下、図面を参照しながら本発明の好適な実施形態について説明する。なお、本発明は以下の実施形態に限定されるものではない。また以下に記載した構成要素には、当業者が容易に想定できるもの、実質的に同一のものが含まれる。さらに以下に記載した構成要素は、適宜組み合わせることができる。   Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

（リチウムイオン二次電池の構造）
図１は、本実施形態の一例に係るリチウムイオン二次電池１０の概念的構造を示す断面図である。本実施形態のリチウムイオン二次電池１０は、正極層１と負極層２が固体電解質層３を介して積層されており、正極層１は正極集電体層４と正極活物質層５からなり、負極層２は負極集電体層６と負極活物質層７からなる。 (Structure of lithium ion secondary battery)
FIG. 1 is a cross-sectional view showing a conceptual structure of a lithium ion secondary battery 10 according to an example of the present embodiment. In the lithium ion secondary battery 10 of this embodiment, a positive electrode layer 1 and a negative electrode layer 2 are laminated via a solid electrolyte layer 3, and the positive electrode layer 1 includes a positive electrode current collector layer 4 and a positive electrode active material layer 5. The negative electrode layer 2 includes a negative electrode current collector layer 6 and a negative electrode active material layer 7.

また、固体電解質層３は固体電解質８を含み、正極活物質層５及び負極活物質層７の一方又は両方にリン酸バナジウムリチウムを含む活物質９を含んでいる。尚、図１では正極活物質層５及び負極活物質層７の両方にリン酸バナジウムリチウムを含む活物質９を含んでいるが、どちらか一方に含まれていてもよい。   The solid electrolyte layer 3 includes a solid electrolyte 8, and one or both of the positive electrode active material layer 5 and the negative electrode active material layer 7 include an active material 9 containing lithium vanadium phosphate. In FIG. 1, both the positive electrode active material layer 5 and the negative electrode active material layer 7 include the active material 9 containing lithium vanadium phosphate, but may be included in either one.

本実施形態のリチウムイオン二次電池１０の固体電解質層３、正極活物質層５及び負極活物質層７を構成する材料はＸ線回折測定により物質同定可能である。また、チタン及びアルミニウムの拡散は、リチウムイオン二次電池１０の断面のＥＤＳやＷＤＳ元素マッピングにより分析可能である。   The materials constituting the solid electrolyte layer 3, the positive electrode active material layer 5, and the negative electrode active material layer 7 of the lithium ion secondary battery 10 of this embodiment can be identified by X-ray diffraction measurement. Further, the diffusion of titanium and aluminum can be analyzed by EDS or WDS element mapping of the cross section of the lithium ion secondary battery 10.

尚、図１では、１組の正極層及び負極層で構成されたリチウムイオン二次電池１０の断面図が示されている。しかし、本実施形態のリチウムイオン二次電池１０に関する技術は、図１に限らず、任意の複数層が積層したリチウムイオン二次電池１０に適用でき、要求されるリチウムイオン二次電池１０の容量や電流仕様に応じて幅広く変化させることが可能である。   FIG. 1 shows a cross-sectional view of a lithium ion secondary battery 10 composed of a pair of positive electrode layer and negative electrode layer. However, the technology relating to the lithium ion secondary battery 10 of the present embodiment is not limited to FIG. 1, and can be applied to the lithium ion secondary battery 10 in which an arbitrary plurality of layers are stacked, and the required capacity of the lithium ion secondary battery 10. It can be changed widely according to the current specification.

（固体電解質）
本実施形態のリチウムイオン二次電池１０の固体電解質層３を構成する固体電解質８としては、電子の伝導性が小さく、リチウムイオンの伝導性が高い材料を用いるのが好ましい。例えば、Ｌｉ３＋ｘ１Ｓｉｘ１Ｐ１−ｘ１Ｏ４（０．４≦ｘ１≦０．６）、Ｌｉ１＋ｘ２Ａｌｘ２Ｔｉ２−ｘ２（ＰＯ４）３（０≦ｘ２≦０．６）、リン酸ゲルマニウムリチウム（ＬｉＧｅ２（ＰＯ４）３）、Ｌｉ２Ｏ−Ｖ２Ｏ５−ＳｉＯ２、Ｌｉ２Ｏ−Ｐ２Ｏ５−Ｂ２Ｏ３、Ｌｉ３ＰＯ４よりなる群から選択される少なくとも１種であることが望ましい。 (Solid electrolyte)
As the solid electrolyte 8 constituting the solid electrolyte layer 3 of the lithium ion secondary battery 10 of the present embodiment, it is preferable to use a material having low electron conductivity and high lithium ion conductivity. For example, Li 3 + x1 Si x1 P 1-x1 O 4 (0.4 ≦ x1 ≦ 0.6), Li 1 + x2 Al x2 Ti 2-x2 (PO 4 ) 3 (0 ≦ x2 ≦ 0.6), germanium phosphate At least one selected from the group consisting of lithium (LiGe 2 (PO 4 ) 3 ), Li 2 O—V 2 O 5 —SiO 2 , Li 2 O—P 2 O 5 —B 2 O 3 , Li 3 PO 4. It is desirable to be a seed.

（正極活物質及び負極活物質）
本実施形態のリチウムイオン二次電池１０の正極活物質層５及び負極活物質層７の一方又は両方がリン酸バナジウムリチウムを含む。リン酸バナジウムリチウムは、ＬｉＶＯＰＯ４、Ｌｉ３Ｖ２（ＰＯ４）３、Ｌｉ２ＶＯＰ２Ｏ７、Ｌｉ２ＶＰ２Ｏ７、Ｌｉ４（ＶＯ）（ＰＯ４）２、及びＬｉ９Ｖ３（Ｐ２Ｏ７）３（ＰＯ４）２のいずれか一つ又は複数であることが好ましく、特に、ＬｉＶＯＰＯ４及びＬｉ３Ｖ２（ＰＯ４）３の一方又は両方であることが好ましい。また、正極活物質層５及び負極活物質７は、リン酸バナジウムリチウム以外の正極活物質及び負極活物質を含んでいても良い。 (Positive electrode active material and negative electrode active material)
One or both of the positive electrode active material layer 5 and the negative electrode active material layer 7 of the lithium ion secondary battery 10 of this embodiment contains lithium vanadium phosphate. Lithium vanadium phosphate is LiVOPO 4 , Li 3 V 2 (PO 4 ) 3 , Li 2 VOP 2 O 7 , Li 2 VP 2 O 7 , Li 4 (VO) (PO 4 ) 2 , and Li 9 V 3 ( Any one or a plurality of P 2 O 7 ) 3 (PO 4 ) 2 is preferable, and in particular, one or both of LiVOPO 4 and Li 3 V 2 (PO 4 ) 3 are preferable. Further, the positive electrode active material layer 5 and the negative electrode active material 7 may contain a positive electrode active material and a negative electrode active material other than lithium vanadium phosphate.

例えば、遷移金属酸化物、遷移金属複合酸化物を含んでいるのが好ましい。具体的には、リチウムマンガン複合酸化物Ｌｉ２Ｍｎｘ３Ｍａ１−ｘ３Ｏ３（０．８≦ｘ３≦１、Ｍａ＝Ｃｏ、Ｎｉ）、コバルト酸リチウム（ＬｉＣｏＯ２）、ニッケル酸リチウム（ＬｉＮｉＯ２）、リチウムマンガンスピネル（ＬｉＭｎ２Ｏ４）、及び、一般式：ＬｉＮｉｘ４Ｃｏｙ４Ｍｎｚ４Ｏ２（ｘ４＋ｙ４＋ｚ４＝１、０≦ｘ４≦１、０≦ｙ４≦１、０≦ｚ４≦１）で表される複合金属酸化物、リチウムバナジウム化合物（ＬｉＶ２Ｏ５）、オリビン型ＬｉＭｂＰＯ４（ただし、Ｍｂは、Ｃｏ、Ｎｉ、Ｍｎ、Ｆｅ、Ｍｇ、Ｎｂ、Ｔｉ、Ａｌ、Ｚｒより選ばれる１種類以上の元素）、Ｌｉ過剰系固溶体正極Ｌｉ２ＭｎＯ３−ＬｉＭｃＯ２（Ｍｃ＝Ｍｎ、Ｃｏ、Ｎｉ）、チタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）、ＬｉａＮｉｘ５Ｃｏｙ５Ａｌｚ５Ｏ２（０．９＜ａ＜１．３、０．９＜ｘ５＋ｙ５＋ｚ５＜１．１）で表される複合金属酸化物のいずれかであることが好ましい。 For example, it preferably contains a transition metal oxide or a transition metal composite oxide. Specifically, the lithium manganese composite oxide Li 2 Mn x3 Ma 1-x3 O 3 (0.8 ≦ x3 ≦ 1, Ma = Co, Ni), lithium cobaltate (LiCoO 2), lithium nickelate (LiNiO 2 ), Lithium manganese spinel (LiMn 2 O 4 ), and a general formula: LiNi x4 Co y4 Mn z4 O 2 (x4 + y4 + z4 = 1, 0 ≦ x4 ≦ 1, 0 ≦ y4 ≦ 1, 0 ≦ z4 ≦ 1) Composite metal oxide, lithium vanadium compound (LiV 2 O 5 ), olivine type LiMbPO 4 (where Mb is one or more selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr) elements), Li excess solid solution positive electrode Li 2 MnO 3 -LiMcO 2 (Mc = Mn, Co, Ni), lithium titanate (Li 4 Ti 5 O 2) is preferably any one of Li a Ni x5 Co y5 Al z5 O 2 (0.9 <a <1.3,0.9 <x5 + y5 + z5 composite metal oxide represented by <1.1) .

ここで、正極活物質層５又は負極活物質層７を構成する活物質には明確な区別がなく、２種類の化合物の電位を比較して、より貴な電位を示す化合物を正極活物質として用い、より卑な電位を示す化合物を負極活物質として用いることができる。また、リチウムイオン放出能とリチウムイオン吸蔵能を同時に併せ持つ化合物であれば、正極活物質層５及び負極活物質層７に同一の化合物を用いてもよい。   Here, there is no clear distinction between the active materials constituting the positive electrode active material layer 5 or the negative electrode active material layer 7, and a compound showing a more noble potential is compared as a positive electrode active material by comparing the potentials of two types of compounds. A compound showing a lower potential can be used as the negative electrode active material. Further, the same compound may be used for the positive electrode active material layer 5 and the negative electrode active material layer 7 as long as the compound has both lithium ion releasing ability and lithium ion storage ability.

本実施例における前記正極活物質又は負極活物質を構成する元素の少なくとも一部と固体電解質を構成する元素の少なくとも一部からなる中間化合物は金属リン酸塩、金属ピロリン酸塩、金属バナジン酸塩であることが好ましい。   The intermediate compound comprising at least a part of the elements constituting the positive electrode active material or the negative electrode active material and at least a part of the elements constituting the solid electrolyte in this example is a metal phosphate, a metal pyrophosphate, a metal vanadate. It is preferable that

金属リン酸塩としてはＬｉＭＰＯ４（Ｍ＝Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ａｌ、Ｔｉ、Ｖ、ＶＯから選ばれる少なくとも１つの元素）、ＭＰＯ４（Ｍ＝Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ａｌ、Ｔｉ、Ｖ、ＶＯから選ばれる少なくとも１つの元素）、金属ピロリン酸塩としてはＬｉ２ＭＰ２Ｏ７（Ｍ＝Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ａｌ、Ｔｉ、Ｖ、ＶＯから選ばれる少なくとも１つの元素）などが上げられ、金属バナジン酸塩としてはＬｉＭＶＯ４（Ｍ＝Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ａｌ、Ｔｉから選ばれる少なくとも１つの元素）、ＭＶＯ４（Ｍ＝Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ａｌ、Ｔｉから選ばれる少なくとも１つの元素）などが上げられ、これらのいずれか一つまたは複数であることが好ましく、特にＬｉＶＯＰＯ４、ＶＯＰＯ４などのＶを含む化合物であることが好ましい。 Examples of the metal phosphate include LiMPO 4 (M = Fe, Mn, Co, Ni, Al, Ti, V, VO), MPO 4 (M = Fe, Mn, Co, Ni, Al, At least one element selected from Ti, V, and VO), and metal pyrophosphate as Li 2 MP 2 O 7 (M = Fe, Mn, Co, Ni, Al, Ti, V, and VO) As the metal vanadate, LiMVO 4 (M = Fe, Mn, Co, Ni, Al, Ti, at least one element selected from Ti), MVO 4 (M = Fe, Mn, Co, Ni , Al, at least one element), and the like are selected from Ti, preferably these are any one or more of the V, such as in particular LiVOPO 4, VOPO 4 It preferably contains no compounds.

本実施形態のリチウムイオン二次電池は、正極活物質層又は負極活物質層と固体電解質層の少なくとも１つの接触面において前記正極活物質又は負極活物質を構成する元素の少なくとも一部と固体電解質を構成する元素の少なくとも一部からなる中間化合物を、前記正極活物質又は前記負極活物質と前記固体電解質が接触する接点接する接触面に有し、前記接触面は、前記正極層又は前記負極層と前記固体電解質層が直接接合する領域Ｌ１と、前記正極層又は負極層と前記固体電解質層が前記中間化合物を介して接合する領域Ｌ２を持ち、前記Ｌ１とＬ２の関係がＬ１＞Ｌ２かつＬ２＞０であることが望ましい。   The lithium ion secondary battery of the present embodiment includes a solid electrolyte and at least a part of elements constituting the positive electrode active material or the negative electrode active material on at least one contact surface of the positive electrode active material layer or the negative electrode active material layer and the solid electrolyte layer. An intermediate compound consisting of at least a part of the elements constituting the positive electrode active material or the negative electrode active material and the contact surface where the solid electrolyte contacts the solid electrolyte, wherein the contact surface is the positive electrode layer or the negative electrode layer And a region L1 where the solid electrolyte layer is directly joined, a region L2 where the positive electrode layer or negative electrode layer and the solid electrolyte layer are joined via the intermediate compound, and the relationship between L1 and L2 is L1> L2 and L2 It is desirable that> 0.

正極活物質層又は負極活物質層を構成する元素の少なくとも一部と固体電解質層を構成する元素の少なくとも一部からなる中間化合物が前記正極活物質層又は負極活物質層と固体電解質層の接触面に存在することにより、正極層又は負極層と固体電解質接触面における元素の濃度勾配が緩和されることによりイオンの移動がスムーズになるためと考えられる。また、前記Ｌ１とＬ２の関係がＬ１＞Ｌ２かつＬ２＞０である場合、正極層又は負極層の活物質と固体電解質の減少を抑制されるためこれを用いたリチウムイオン二次電池の容量低下を抑制しつつ、高い放電レート特性が得られるものと考えられる。   An intermediate compound comprising at least a part of the elements constituting the positive electrode active material layer or the negative electrode active material layer and at least a part of the elements constituting the solid electrolyte layer is in contact between the positive electrode active material layer or the negative electrode active material layer and the solid electrolyte layer. It is considered that the ion migration is smooth due to relaxation of the concentration gradient of the element in the contact surface between the positive electrode layer or the negative electrode layer and the solid electrolyte by being present on the surface. In addition, when the relationship between L1 and L2 is L1> L2 and L2> 0, the decrease in the capacity of the lithium ion secondary battery using the active material and the solid electrolyte in the positive electrode layer or the negative electrode layer is suppressed. It is considered that high discharge rate characteristics can be obtained while suppressing the above.

本実施形態において複数種の中間化合物を含む場合、それぞれの中間化合物からなるＬ２領域の和がＬ１＞Ｌ２かつＬ２＞０を満たせばよい。   In the present embodiment, when a plurality of types of intermediate compounds are included, the sum of the L2 regions formed by the respective intermediate compounds may satisfy L1> L2 and L2> 0.

本実施形態における前記正極層又は前記負極層と前記固体電解質層が直接接合する領域Ｌ１と、前記正極層又は負極層と前記固体電解質層が前記中間化合物を介して接合する領域Ｌ２の関係はＬ１が７０％以上でありＬ２で３０％以下であることが好ましく、Ｌ１が９０％以上でありＬ２が１０％以下であることが更に好ましい。   In this embodiment, the relationship between the region L1 where the positive electrode layer or the negative electrode layer and the solid electrolyte layer are directly bonded, and the region L2 where the positive electrode layer or negative electrode layer and the solid electrolyte layer are bonded via the intermediate compound is L1. Is 70% or more and L2 is preferably 30% or less, more preferably L1 is 90% or more and L2 is 10% or less.

これにより本実施例におけるリチウムイオン二次電池の容量低下を更に抑制しつつ、高い放電レート特性を得ることができる。   Thereby, a high discharge rate characteristic can be obtained while further suppressing the capacity reduction of the lithium ion secondary battery in the present embodiment.

上記Ｌ１及びＬ２の領域は、本実施形態におけるリチウムイオン二次電池の断面をＳＥＭ、ＴＥＭなどにより観察することで評価することができる。   The regions L1 and L2 can be evaluated by observing the cross section of the lithium ion secondary battery in the present embodiment with SEM, TEM, or the like.

本実施形態におけるＬ１領域は電極の断面を観察した際、正極層活物質又は負極活物質層と固体電解質層間が直接接合する領域の長さの総和であり、Ｌ２領域は正極層又は負極層と固体電解質層が中間化合物を介して接合する領域の長さの総和である。   The L1 region in the present embodiment is the sum of the lengths of the regions where the positive electrode active material or negative electrode active material layer and the solid electrolyte layer are directly joined when the cross section of the electrode is observed, and the L2 region is the positive electrode layer or negative electrode layer. It is the sum total of the length of the area | region where a solid electrolyte layer joins via an intermediate compound.

本実施形態におけるリチウムイオン二次電池の断面をＳＥＭで観察した際、正極活物質層又は負極活物質層と固体電解質層の接触面の画像１０点を観察した際、各接触面における正極活物質又は負極活物質と固体電解質層が直接接合している領域Ｌ１と前記中間化合物を介して接合する領域Ｌ２の平均を取り、その平均からＬ１、Ｌ２の関係を計算することができる。   When the cross section of the lithium ion secondary battery in the present embodiment is observed with an SEM, when 10 images of the contact surface of the positive electrode active material layer or the negative electrode active material layer and the solid electrolyte layer are observed, the positive electrode active material on each contact surface Alternatively, the average of the region L1 where the negative electrode active material and the solid electrolyte layer are directly joined and the region L2 joined via the intermediate compound can be taken, and the relationship between L1 and L2 can be calculated from the average.

本実施形態におけるＬ１領域は正極活物質層又は負極活物質層と固体電解質層の界面を示す。また、Ｌ２領域は中間化合物が前記界面と接する領域間を示す。   L1 area | region in this embodiment shows the interface of a positive electrode active material layer or a negative electrode active material layer, and a solid electrolyte layer. Moreover, L2 area | region shows between the area | regions which an intermediate compound touches the said interface.

なお、本実施形態におけるＬ１領域及びＬ２領域の関係を算出する際、正極活物質層又は負極活物質層と固体電解質層が直接接合する領域及び中間化合物を介して接合する領域のいずれか一方又は両方が完全な平面でない場合、各Ｌ１領域及びＬ２領域の両端を直線で結んだ、それぞれの接合領域を直線近似した長さからＬ１及びＬ２領域の関係を計算することができる。   In calculating the relationship between the L1 region and the L2 region in the present embodiment, either the positive electrode active material layer or the region where the negative electrode active material layer and the solid electrolyte layer are directly bonded and the region bonded via the intermediate compound or When both are not perfect planes, the relationship between the L1 and L2 regions can be calculated from the length obtained by linearly approximating each joint region where both ends of each L1 region and L2 region are connected by straight lines.

特に、固体電解質層３にＬｉ１＋ｘ２Ａｌｘ２Ｔｉ２−ｘ２（ＰＯ４）３（０≦ｘ２≦０．６）、正極活物質層５及び負極活物質層７の一方又は両方にＬｉＶＯＰＯ４及びＬｉ３Ｖ２（ＰＯ４）３の一方又は両方を用いると、正極活物質及び負極活物質の一方又は両方と固体電解質の界面における接合が強固なものになると同時に、接触面積を広くできるため望ましい。 In particular, Li 1 + x2 Al x2 Ti 2-x2 (PO 4 ) 3 (0 ≦ x2 ≦ 0.6) on the solid electrolyte layer 3, LiVOPO 4 and LiO 4 on one or both of the positive electrode active material layer 5 and the negative electrode active material layer 7. The use of one or both of 3 V 2 (PO 4 ) 3 is desirable because the bonding at the interface between one or both of the positive electrode active material and the negative electrode active material and the solid electrolyte becomes strong and the contact area can be widened.

上記理由から、本実施例における中間化合物はＡｌ、Ｔｉ、Ｖ、Ｐからなる元素を少なくとも１つを含有する化合物であることが好ましい。   For the above reasons, the intermediate compound in this example is preferably a compound containing at least one element composed of Al, Ti, V, and P.

また、正極活物質層５又は負極活物質層７を構成する活物質には明確な区別がなく、２種類の化合物の電位を比較して、より貴な電位を示す化合物を正極活物質として用い、より卑な電位を示す化合物を負極活物質として用いることができる。   Moreover, there is no clear distinction in the active material which comprises the positive electrode active material layer 5 or the negative electrode active material layer 7, Comparing the electric potential of two types of compounds, and using the compound which shows a more noble electric potential as a positive electrode active material A compound exhibiting a lower potential can be used as the negative electrode active material.

（正極集電体層及び負極集電体層）
本実施形態のリチウムイオン二次電池１０の正極集電体層４及び負極集電体層６を構成する集電体材料は、導電率が大きい材料を用いるのが好ましく、例えば、銀、パラジウム、金、プラチナ、アルミニウム、銅、ニッケルなどを用いるのが好ましい。特に、銅は正極活物質、負極活物質及び固体電解質と反応し難く、さらにリチウムイオン二次電池１０の内部抵抗の低減に効果があるため好ましい。正極集電体層４及び負極集電体層６を構成する材料は、正極と負極で同じであってもよいし、異なっていてもよい。 (Positive electrode current collector layer and negative electrode current collector layer)
As the current collector material constituting the positive electrode current collector layer 4 and the negative electrode current collector layer 6 of the lithium ion secondary battery 10 of the present embodiment, it is preferable to use a material having a high conductivity, for example, silver, palladium, Gold, platinum, aluminum, copper, nickel, etc. are preferably used. In particular, copper is preferable because it hardly reacts with the positive electrode active material, the negative electrode active material, and the solid electrolyte, and further has an effect of reducing the internal resistance of the lithium ion secondary battery 10. The materials constituting the positive electrode current collector layer 4 and the negative electrode current collector layer 6 may be the same for the positive electrode and the negative electrode, or may be different.

本実施形態におけるリチウムイオン二次電池１０の正極集電体層４及び負極集電体層６を構成する材料は、上記集電体材料の他に正極活物質又は負極活物質を含むことが好ましい。   The materials constituting the positive electrode current collector layer 4 and the negative electrode current collector layer 6 of the lithium ion secondary battery 10 in this embodiment preferably include a positive electrode active material or a negative electrode active material in addition to the current collector material. .

正極集電体層又は負極集電体層を集電体材料と活物質とを複合化したものを用いることにより、集電体層と正極活物質層又は負極活物質層との密着性が向上するため望ましい。   Adhesion between the current collector layer and the positive electrode active material layer or the negative electrode active material layer is improved by using a composite of the current collector material and the active material for the positive electrode current collector layer or the negative electrode current collector layer. This is desirable.

本実施形態における集電体層における集電体材料と活物質との複合比率は、集電体として機能する限り特に限定はされない。   The composite ratio of the current collector material and the active material in the current collector layer in the present embodiment is not particularly limited as long as it functions as a current collector.

（リチウムイオン二次電池の製造方法）
本実施形態のリチウムイオン二次電池１０は、正極集電体層４、正極活物質層５、固体電解質層３、負極活物質層７、及び、負極集電体層６の各材料をペースト化し、塗布乾燥してグリーンシートを作製し、係るグリーンシートを積層し、作製した積層体を同時に焼成することにより製造する。 (Method for producing lithium ion secondary battery)
In the lithium ion secondary battery 10 of this embodiment, the positive electrode current collector layer 4, the positive electrode active material layer 5, the solid electrolyte layer 3, the negative electrode active material layer 7, and the negative electrode current collector layer 6 are pasted. The green sheet is produced by coating and drying, the green sheets are laminated, and the produced laminate is fired at the same time.

ペースト化の方法は、特に限定されないが、例えば、ビヒクルに上記各材料の粉末を混合してペーストを得ることができる。ここで、ビヒクルとは、液相における媒質の総称である。ビヒクルには、溶媒、バインダーが含まれる。係る方法により、正極集電体層４用のペースト、正極活物質層５用のペースト、固体電解質層３用のペースト、負極活物質層７用のペースト、及び、負極集電体層６用のペーストを作製する。   The method for forming the paste is not particularly limited, and for example, a paste can be obtained by mixing the powder of each of the above materials in a vehicle. Here, the vehicle is a general term for the medium in the liquid phase. The vehicle includes a solvent and a binder. By such a method, the paste for the positive electrode current collector layer 4, the paste for the positive electrode active material layer 5, the paste for the solid electrolyte layer 3, the paste for the negative electrode active material layer 7, and the negative electrode current collector layer 6 Make a paste.

作製したペーストをＰＥＴなどの基材上に所望の順序で塗布し、必要に応じ乾燥させた後、基材を剥離し、グリーンシートを作製する。ペーストの塗布方法は、特に限定されず、スクリーン印刷、塗布、転写、ドクターブレード等の公知の方法を採用することができる。   The prepared paste is applied in a desired order on a substrate such as PET and dried as necessary, and then the substrate is peeled off to produce a green sheet. The paste application method is not particularly limited, and a known method such as screen printing, application, transfer, doctor blade, or the like can be employed.

作製した正極集電体層４用、正極活物質層５用、固体電解質層３用、負極活物質層７用、及び、負極集電体層６用のそれぞれのグリーンシートを所望の順序、積層数で積み重ね、必要に応じアライメント、切断等を行い、積層体を作製する。並列型又は直並列型の電池を作製する場合は、正極層の端面と負極層の端面が一致しないようにアライメントを行い積み重ねるのが好ましい。   The green sheets for the positive electrode current collector layer 4, the positive electrode active material layer 5, the solid electrolyte layer 3, the negative electrode active material layer 7, and the negative electrode current collector layer 6 that are produced are laminated in a desired order. Stacked by number, alignment, cutting, etc. are performed as necessary to produce a laminate. In the case of manufacturing a parallel type or series-parallel type battery, it is preferable to align and stack the end surfaces of the positive electrode layer and the negative electrode layer so that they do not coincide with each other.

作製した積層体を一括して圧着する。圧着は加熱しながら行うが、加熱温度は、例えば、４０〜９０℃とする。   The produced laminate is pressed together. The pressure bonding is performed while heating, and the heating temperature is, for example, 40 to 90 ° C.

圧着した積層体を、例えば、窒素雰囲気下で加熱し焼成を行う。本実施形態のリチウムイオン二次電池１０の製造では、焼成温度は、７２０〜１０００℃の範囲とするのが好ましい。７２０℃未満ではチタン及びアルミニウムの拡散や焼結が十分進まず、１０００℃を超えるとリン酸バナジウムリチウムが融解するなどの問題が発生するためである。さらに７５０〜９００℃の範囲とするのがより好ましい。７５０〜９００℃の範囲とする方が、チタン及びアルミニウムの拡散や焼結の促進、製造コストの低減により好適である。焼成時間は、例えば、０．１〜３時間とする。   For example, the pressure-bonded laminate is heated and fired in a nitrogen atmosphere. In manufacture of the lithium ion secondary battery 10 of this embodiment, it is preferable that a calcination temperature shall be the range of 720-1000 degreeC. When the temperature is lower than 720 ° C., diffusion and sintering of titanium and aluminum do not proceed sufficiently, and when the temperature exceeds 1000 ° C., problems such as melting of lithium vanadium phosphate occur. Furthermore, it is more preferable to set it as the range of 750-900 degreeC. A range of 750 to 900 ° C. is more preferable for accelerating diffusion and sintering of titanium and aluminum and reducing manufacturing costs. The firing time is, for example, 0.1 to 3 hours.

（実施例１）
以下に、実施例を用いて本発明を詳細に説明するが、本発明はこれらの実施例に限定されない。なお、部表示は、断りのない限り、重量部である。 Example 1
EXAMPLES The present invention will be described in detail below using examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, a part display is a weight part.

（活物質の作製）
活物質として、以下の方法で作製したＬｉ３Ｖ２（ＰＯ４）３を用いた。Ｌｉ２ＣＯ３とＶ２Ｏ５とＮＨ４Ｈ２ＰＯ４とを出発材料とし、これらをモル比３：２：６となるように秤量し、水を溶媒としてボールミルで１６時間湿式混合を行った後、脱水乾燥した。得られた粉体を８５０℃で２時間、窒素水素混合ガス中で仮焼した。仮焼品を粗粉砕し、水を溶媒としてボールミルで４時間湿式粉砕を行った後、脱水乾燥して活物質粉末を得た。この粉体の平均粒径は２．０μｍであった。作製した粉体の組成がＬｉ３Ｖ２（ＰＯ４）３であることを、Ｘ線回折装置を使用して確認した。 (Production of active material)
Li 3 V 2 (PO 4 ) 3 produced by the following method was used as the active material. Using Li 2 CO 3 , V 2 O 5 and NH 4 H 2 PO 4 as starting materials, these were weighed so as to have a molar ratio of 3: 2: 6, and wet mixed in a ball mill for 16 hours using water as a solvent. And then dehydrated and dried. The obtained powder was calcined in a nitrogen-hydrogen mixed gas at 850 ° C. for 2 hours. The calcined product was coarsely pulverized, wet pulverized with a ball mill for 4 hours using water as a solvent, and then dehydrated and dried to obtain an active material powder. The average particle size of this powder was 2.0 μm. The composition of the powder produced is Li 3 V 2 (PO 4) is 3, was confirmed using X-ray diffractometer.

（活物質ペーストの作製）
活物質ペーストは、この活物質粉末１００部に、バインダーとしてエチルセルロース１５部と、溶媒としてジヒドロターピネオール６５部とを加えて、三本ロールで混練・分散して活物質ペーストを作製した。 (Production of active material paste)
The active material paste was prepared by adding 15 parts of ethyl cellulose as a binder and 65 parts of dihydroterpineol as a solvent to 100 parts of this active material powder, and kneading and dispersing with three rolls.

（固体電解質シートの作製）
固体電解質として、以下の方法で作製したＬｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３を用いた。Ｌｉ２ＣＯ３とＡｌ２Ｏ３とＴｉＯ２とＮＨ４Ｈ２ＰＯ４を出発材料として、これらをモル比０．６５：０．１５：１．７：３となるように秤量し、水を溶媒としてボールミルで１６時間湿式混合を行った後、脱水乾燥した。得られた粉体を８００℃で２時間、空気中で仮焼した。仮焼品を粗粉砕し、水を溶媒としてボールミルで２４時間湿式粉砕を行った後、脱水乾燥して固体電解質の粉末を得た。この粉体の平均粒径は０．２μｍであった。作製した粉体の組成がＬｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３であることを、Ｘ線回折装置を使用して確認した。 (Preparation of solid electrolyte sheet)
As the solid electrolyte, Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 prepared by the following method was used. Using Li 2 CO 3 , Al 2 O 3 , TiO 2 and NH 4 H 2 PO 4 as starting materials, these were weighed to a molar ratio of 0.65: 0.15: 1.7: 3, and water was added. After wet mixing with a ball mill as a solvent for 16 hours, it was dehydrated and dried. The obtained powder was calcined in air at 800 ° C. for 2 hours. The calcined product was coarsely pulverized, wet pulverized with a ball mill for 24 hours using water as a solvent, and then dehydrated to obtain a solid electrolyte powder. The average particle size of this powder was 0.2 μm. The composition of the powder produced is Li 1.3 Al 0.3 Ti 1.7 (PO 4) is 3, was confirmed using X-ray diffractometer.

次いで、この粉末１００部に、溶媒としてエタノール１００部、トルエン２００部をボールミルで加えて湿式混合した。その後ポリビニールブチラール系バインダー１６部とフタル酸ベンジルブチル４．８部をさらに投入し、混合して固体電解質ペーストを調製した。この固体電解質ペーストをドクターブレード法でＰＥＴフィルムを基材としてシート成形し、厚さ１５μｍの固体電解質シートを得た。   Next, 100 parts of ethanol and 200 parts of toluene were added to 100 parts of the powder by a ball mill and wet mixed. Thereafter, 16 parts of polyvinyl butyral binder and 4.8 parts of benzylbutyl phthalate were further added and mixed to prepare a solid electrolyte paste. This solid electrolyte paste was formed into a sheet by a doctor blade method using a PET film as a base material to obtain a solid electrolyte sheet having a thickness of 15 μm.

（中間化合物の作製）
中間化合物として、以下の方法で作製したＬｉＶＯＰＯ４を用いた。Ｌｉ２ＣＯ３とＶ２Ｏ５とＮＨ４Ｈ２ＰＯ４とを出発材料とし、これらをモル比２：１：２となるように秤量し、水を溶媒としてボールミルで４時間湿式混合を行った後、脱水乾燥した。得られた粉体を３００℃で２時間、大気雰囲気中で仮焼した。仮焼品を粗粉砕し、水を溶媒としてボールミルで１２時間湿式粉砕を行った後、脱水乾燥して活物質粉末を得た。この粉体の平均粒径は０．０５μｍであった。作製した粉体の組成がＬｉＶＯＰＯ４であることを、Ｘ線回折装置を使用して確認した。
(Preparation of intermediate compound)
LiVOPO 4 produced by the following method was used as an intermediate compound. Li 2 CO 3 , V 2 O 5 and NH 4 H 2 PO 4 are used as starting materials, these are weighed to a molar ratio of 2: 1: 2, and wet-mixed for 4 hours in a ball mill using water as a solvent. And then dehydrated and dried. The obtained powder was calcined in the air at 300 ° C. for 2 hours. The calcined product was coarsely pulverized, wet pulverized with a ball mill for 12 hours using water as a solvent, and then dehydrated and dried to obtain an active material powder. The average particle size of this powder was 0.05 μm. The composition of the powder produced is LiVOPO 4, was confirmed using X-ray diffractometer.

（中間化合物ペーストの作製）
中間化合物ペーストは、得られた中間化合物粉末１０部に、バインダーとしてエチルセルロース５部と、溶媒としてジヒドロターピネオール６５部とを加えて、三本ロールで混練・分散して中間化合物ペーストを作製した。 (Preparation of intermediate compound paste)
The intermediate compound paste was prepared by adding 5 parts of ethyl cellulose as a binder and 65 parts of dihydroterpineol as a solvent to 10 parts of the obtained intermediate compound powder, and kneading and dispersing with three rolls to prepare an intermediate compound paste.

（集電体ペーストの作製）
集電体としてＣｕとＬｉ３Ｖ２（ＰＯ４）３とを体積比率で６０：４０となるように混合した後、バインダーとしてエチルセルロース１０部と、溶媒としてジヒドロターピネオール５０部を加えて三本ロールで混練・分散して集電体ペーストを作製した。Ｃｕの平均粒径は０．６μｍであった。 (Preparation of current collector paste)
After mixing Cu and Li 3 V 2 (PO 4 ) 3 as a current collector so as to have a volume ratio of 60:40, 10 parts of ethyl cellulose as a binder and 50 parts of dihydroterpineol as a solvent were added to form a three-roll. A current collector paste was prepared by kneading and dispersing. The average particle diameter of Cu was 0.6 μm.

（端子電極ペーストの作製）
銀粉末とエポキシ樹脂、溶剤とを三本ロールで混錬・分散し、熱硬化型の導電ペーストを作製した。 (Preparation of terminal electrode paste)
Silver powder, epoxy resin, and solvent were kneaded and dispersed with three rolls to produce a thermosetting conductive paste.

これらのペーストを用いて、以下のようにしてリチウムイオン二次電池を作製した。   Using these pastes, lithium ion secondary batteries were produced as follows.

（活物質ユニットの作製）
上記の固体電解質シート上に、スクリーン印刷により厚さ１００ｎｍで中間化合物ペーストを印刷した。次に、印刷した中間化合物ペーストを８０〜１００℃で５〜１０分間乾燥し、更にその上に、スクリーン印刷により厚さ５μｍで活物質ペーストを印刷した。次に、印刷した活物質ペーストを８０〜１００℃で５〜１０分間乾燥し、その上に、スクリーン印刷により厚さ５μｍで集電体ペーストを印刷した。次に、印刷した集電体ペーストを８０〜１００℃で５〜１０分間乾燥し、更にその上に、スクリーン印刷により厚さ５μｍで活物質ペーストを再度印刷した。印刷した活物質ペーストを８０〜１００℃で５〜１０分間乾燥し、次いでＰＥＴフィルムを剥離した。このようにして、固体電解質シート上に、活物質ペースト、集電体ペースト、活物質ペーストがこの順に印刷・乾燥された活物質ユニットのシートを得た。 (Production of active material unit)
An intermediate compound paste was printed on the solid electrolyte sheet with a thickness of 100 nm by screen printing. Next, the printed intermediate compound paste was dried at 80 to 100 ° C. for 5 to 10 minutes, and further, an active material paste was printed thereon with a thickness of 5 μm by screen printing. Next, the printed active material paste was dried at 80 to 100 ° C. for 5 to 10 minutes, and the current collector paste was printed thereon with a thickness of 5 μm by screen printing. Next, the printed current collector paste was dried at 80 to 100 ° C. for 5 to 10 minutes, and further, the active material paste was printed again at a thickness of 5 μm by screen printing. The printed active material paste was dried at 80 to 100 ° C. for 5 to 10 minutes, and then the PET film was peeled off. In this way, an active material unit sheet in which the active material paste, the current collector paste, and the active material paste were printed and dried in this order on the solid electrolyte sheet was obtained.

（積層体の作製）
活物質ユニット二枚を、固体電解質を介するようにして積み重ねた。このとき、一枚目の活物質ユニットの集電体ペースト層が一の端面にのみ延出し、二枚目の活物質ユニットの集電体ペースト層が他の面にのみ延出するように、各ユニットをずらして積み重ねた。この積み重ねられたユニットの両面に厚さ５００μｍとなるように固体電解質シートを重ね、その後、これを温度８０℃で圧力１０００ｋｇｆ／ｃｍ２〔９８ＭＰａ〕で成形し、次いで切断して積層ブロックを作製した。その後、積層ブロックを同時焼成して積層体を得た。同時焼成は、窒素中で昇温速度２００℃／時間で焼成温度８４０℃まで昇温して、その温度に２時間保持し、焼成後は自然冷却した。同時焼成後の電池外観サイズは、３．２ｍｍ×２．５ｍｍ×０．４ｍｍであった。 (Production of laminate)
Two active material units were stacked with a solid electrolyte interposed therebetween. At this time, the current collector paste layer of the first active material unit extends only to one end surface, and the current collector paste layer of the second active material unit extends only to the other surface, Each unit was staggered and stacked. A solid electrolyte sheet was stacked on both surfaces of the stacked unit so as to have a thickness of 500 μm, and then this was molded at a temperature of 80 ° C. and a pressure of 1000 kgf / cm 2 [98 MPa], and then cut to prepare a laminated block. . Thereafter, the laminated block was simultaneously fired to obtain a laminated body. In the simultaneous firing, the temperature was increased to a firing temperature of 840 ° C. at a temperature rise rate of 200 ° C./hour in nitrogen, maintained at that temperature for 2 hours, and naturally cooled after firing. The battery appearance size after co-firing was 3.2 mm × 2.5 mm × 0.4 mm.

（端子電極形成工程）
積層体の端面に端子電極ペーストを塗布し、１５０℃、３０分の熱硬化を行い、一対の端子電極を形成してリチウムイオンニ次電池を得た。 (Terminal electrode formation process)
A terminal electrode paste was applied to the end face of the laminate, and thermosetting was performed at 150 ° C. for 30 minutes to form a pair of terminal electrodes to obtain a lithium ion secondary battery.

（中間化合物観察）
実施例１により得られたリチウムイオン二次電池の断面をＸＲＤにて解析した所、活物質層にＬｉ３Ｖ２（ＰＯ４）３を、固体電解質層にＬｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３を、また、活物質層と固体電解質層の接触面にＬｉＶＯＰＯ４の存在を確認した。また、ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９３％、Ｌ２が７％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Intermediate compound observation)
When the cross section of the lithium ion secondary battery obtained in Example 1 was analyzed by XRD, Li 3 V 2 (PO 4 ) 3 was used as the active material layer, and Li 1.3 Al 0.3 Ti was used as the solid electrolyte layer. The presence of 1.7 (PO 4 ) 3 and LiVOPO 4 on the contact surface between the active material layer and the solid electrolyte layer was confirmed. Further, when observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 93%. , L2 was 7%, and it was confirmed that L2> 0 and L1> L2.

（実施例２）
活物質ユニットの作製において、中間化合物ペースト作製時に混合した中間化合物粉末を５部としたこと以外は実施例１と同様にして実施例２のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９８％、Ｌ２が２％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 2)
In the production of the active material unit, a lithium ion secondary battery of Example 2 was produced in the same manner as in Example 1 except that 5 parts of the intermediate compound powder mixed at the time of producing the intermediate compound paste was used. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 98%, L2 Was 2%, and it was confirmed that L2> 0 and L1> L2.

（実施例３）
活物質ユニットの作製において、中間化合物ペースト作製時に混合した中間化合物粉末を３０部としたこと以外は実施例１と同様にして実施例２のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が７５％、Ｌ２が２５％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 3)
In the production of the active material unit, a lithium ion secondary battery of Example 2 was produced in the same manner as in Example 1 except that 30 parts of the intermediate compound powder mixed at the time of producing the intermediate compound paste was used. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 75%, L2 Was 25%, and it was confirmed that L2> 0 and L1> L2.

（実施例４）
活物質ユニットの作製において、中間化合物ペースト作製時に混合した中間化合物粉末を４０部としたこと以外は実施例１と同様にして実施例２のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が６９％、Ｌ２が３１であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 Example 4
In the production of the active material unit, a lithium ion secondary battery of Example 2 was produced in the same manner as in Example 1 except that 40 parts of the intermediate compound powder mixed at the time of producing the intermediate compound paste was used. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 69%, L2 Was 31, L2> 0 and L1> L2.

（実施例５）
活物質ユニットの作製において、中間化合物ペースト作製時に混合した中間化合物粉末を６０部としたこと以外は実施例１と同様にして実施例２のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が５５％、Ｌ２が４５％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 5)
In the production of the active material unit, a lithium ion secondary battery of Example 2 was produced in the same manner as in Example 1 except that 60 parts of the intermediate compound powder mixed at the time of producing the intermediate compound paste was used. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 55%, L2 Was 45%, and it was confirmed that L2> 0 and L1> L2.

（実施例６）
中間化合物としてＡｌＰＯ４を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９１％、Ｌ２が９％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 6)
A lithium ion secondary battery of Example 7 was made in the same manner as Example 1 except that AlPO 4 was used as an intermediate compound. When observed with SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed on the contact surface between the active material layer and the solid electrolyte layer, L1 was 91%, L2 Was 9%, and it was confirmed that L2> 0 and L1> L2.

（実施例７）
中間化合物としてＬｉＴｉＡｌＯ４を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９４％、Ｌ２が６％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 7)
A lithium ion secondary battery of Example 7 was produced in the same manner as Example 1 except that LiTiAlO 4 was used as an intermediate compound. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 94%, L2 Was 6%, and it was confirmed that L2> 0 and L1> L2.

（実施例８）
中間化合物としてＶＯＰＯ４を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９２％、Ｌ２が８％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 8)
A lithium ion secondary battery of Example 7 was produced in the same manner as Example 1 except that VOPO 4 was used as an intermediate compound. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 92%, L2 Was 8%, and it was confirmed that L2> 0 and L1> L2.

（実施例９）
中間化合物としてＡｌＶＯ４を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９１％、Ｌ２が９％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 Example 9
A lithium ion secondary battery of Example 7 was made in the same manner as Example 1 except that AlVO 4 was used as an intermediate compound. When observed with SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed on the contact surface between the active material layer and the solid electrolyte layer, L1 was 91%, L2 Was 9%, and it was confirmed that L2> 0 and L1> L2.

（実施例１０）
中間化合物としてＬｉＴｉＶＯ４を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９３％、Ｌ２が７％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 10)
A lithium ion secondary battery of Example 7 was produced in the same manner as Example 1 except that LiTiVO 4 was used as an intermediate compound. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 93%, L2 Was 7%, and it was confirmed that L2> 0 and L1> L2.

（実施例１１）
中間化合物としてＴｉＯ２を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９０％、Ｌ２が１０％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 11)
A lithium ion secondary battery of Example 7 was produced in the same manner as Example 1 except that TiO 2 was used as an intermediate compound. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 90%, L2 Was 10%, and it was confirmed that L2> 0 and L1> L2.

（実施例１２）
中間化合物としてＡｌ２Ｏ３を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９２％、Ｌ２が８％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 12)
A lithium ion secondary battery of Example 7 was produced in the same manner as Example 1 except that Al 2 O 3 was used as an intermediate compound. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 92%, L2 Was 8%, and it was confirmed that L2> 0 and L1> L2.

（実施例１３）
中間化合物としてＶ２Ｏ５を用いたこと以外、実施例１と同様にして実施例７のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が９１％、Ｌ２が９％であり、Ｌ２＞０かつＬ１＞Ｌ２であることを確認した。 (Example 13)
A lithium ion secondary battery of Example 7 was produced in the same manner as Example 1 except that V 2 O 5 was used as an intermediate compound. When observed with SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed on the contact surface between the active material layer and the solid electrolyte layer, L1 was 91%, L2 Was 9%, and it was confirmed that L2> 0 and L1> L2.

（比較例１）
活物質ユニットの作製において、中間化合物のペーストをスクリーン印刷しなかったことを以外は実施例１と同様にして比較例１のリチウムイオン二次電池を作製した。 (Comparative Example 1)
A lithium ion secondary battery of Comparative Example 1 was produced in the same manner as in Example 1 except that in the production of the active material unit, the intermediate compound paste was not screen-printed.

（比較例２）
活物質ユニットの作製において、中間化合物ペースト作製時に混合した中間化合物粉末を７５部としたこと以外は実施例１と同様にして実施例２のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が４５％、Ｌ２が５５％であり、Ｌ２＞０かつＬ１＞Ｌ２を満たさないことを確認した。 (Comparative Example 2)
In the production of the active material unit, a lithium ion secondary battery of Example 2 was produced in the same manner as in Example 1 except that 75 parts of the intermediate compound powder mixed at the time of producing the intermediate compound paste was used. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 45%, L2 Was 55%, and it was confirmed that L2> 0 and L1> L2 were not satisfied.

（比較例３）
活物質ユニットの作製において、中間化合物ペースト作製時に混合した中間化合物粉末を１００部としたこと以外は実施例１と同様にして実施例２のリチウムイオン二次電池を作製した。ＳＥＭで観察した際、活物質層と固体電解質層の接触面の画像１０点を観察し、活物質層と固体電解質層の接触面において、Ｌ１及びＬ２を観察した所、Ｌ１が２０％、Ｌ２が８０％であり、Ｌ２＞０かつＬ１＞Ｌ２を満たさないことを確認した。 (Comparative Example 3)
In the production of the active material unit, a lithium ion secondary battery of Example 2 was produced in the same manner as in Example 1 except that 100 parts of the intermediate compound powder mixed at the time of producing the intermediate compound paste was used. When observed by SEM, 10 images of the contact surface between the active material layer and the solid electrolyte layer were observed, and when L1 and L2 were observed at the contact surface between the active material layer and the solid electrolyte layer, L1 was 20%, L2 Was 80%, and it was confirmed that L2> 0 and L1> L2 were not satisfied.

（電池の評価）
それぞれの端子電極にリード線を取り付け、繰り返し充放電試験を行った。測定条件は、充電及び放電時の電流を０．２μＡで充放電した後２．０μＡで１０サイクル充放電を行った。充電時及び放電時の打ち切り電圧をそれぞれ４．０Ｖ及び０Ｖとした。上記条件において、０．２μＡで充放電した際の放電容量Ｄ１に対する２．０μＡで充放電した際の１０サイクル目の放電容量Ｄ２の比率Ｄ２／Ｄ１＊１００の値を放電レート特性の値とした。また、充放電温度は室温（２５℃）と高温（６０℃）にて実施し、各温度において得られた放電レート特性と２５℃における初回放電容量の値を表１に示す。 (Battery evaluation)
Lead wires were attached to the respective terminal electrodes, and repeated charge / discharge tests were conducted. Measurement conditions were such that the current during charging and discharging was charged and discharged at 0.2 μA, and then charged and discharged at 2.0 μA for 10 cycles. The truncation voltages during charging and discharging were 4.0 V and 0 V, respectively. Under the above conditions, the value of the ratio D2 / D1 * 100 of the discharge capacity D2 at the 10th cycle when charging / discharging at 2.0 μA with respect to the discharge capacity D1 when charging / discharging at 0.2 μA was used as the value of the discharge rate characteristic. . The charge / discharge temperature was carried out at room temperature (25 ° C.) and high temperature (60 ° C.).

Figure 0006316091
Figure 0006316091

表１より、活物質層と固体電解質層の接触面において中間化合物が存在し、前記正極層又は前記負極層と前記固体電解質層が直接接合する領域Ｌ１と、前記正極層又は負極層と前記固体電解質層が前記中間化合物を介して接合する領域Ｌ２の関係がＬ１＞Ｌ２かつＬ２＞０である場合に放電容量の低下を抑制しつつ、高い放電レート特性を示すことが分かった。また、実施例１〜１０から、前記中間化合物が金属リン酸塩、金属ピロリン酸塩、金属バナジン酸塩からなる場合、高温において良好な放電レート特性を示すことから熱安定性の向上も見られた。   From Table 1, an intermediate compound is present at the contact surface between the active material layer and the solid electrolyte layer, the region L1 where the positive electrode layer or the negative electrode layer and the solid electrolyte layer are directly joined, the positive electrode layer or the negative electrode layer, and the solid It has been found that when the relationship of the region L2 where the electrolyte layer is joined via the intermediate compound is L1> L2 and L2> 0, a high discharge rate characteristic is exhibited while suppressing a decrease in discharge capacity. In addition, from Examples 1 to 10, when the intermediate compound is composed of a metal phosphate, a metal pyrophosphate, and a metal vanadate, it exhibits good discharge rate characteristics at high temperatures, so that an improvement in thermal stability is also seen. It was.

以上のように、本発明に係るリチウムイオン二次電池は容量低下を抑制しつつ、放電レート特性の向上に効果がある。高容量、高放電レート特性を提供することにより、特に、エレクトロニクスの分野で大きく寄与する。   As described above, the lithium ion secondary battery according to the present invention is effective in improving the discharge rate characteristics while suppressing a decrease in capacity. By providing high capacity and high discharge rate characteristics, it contributes greatly, especially in the field of electronics.

１ 正極層
２ 負極層
３ 固体電解質層
４ 正極集電体層
５ 正極活物質層
６ 負極集電体層
７ 負極活物質層
８ 固体電解質
９ 活物質
１０ リチウムイオン二次電池 DESCRIPTION OF SYMBOLS 1 Positive electrode layer 2 Negative electrode layer 3 Solid electrolyte layer 4 Positive electrode collector layer 5 Positive electrode active material layer 6 Negative electrode collector layer 7 Negative electrode active material layer 8 Solid electrolyte 9 Active material 10 Lithium ion secondary battery

Claims (5)

正極集電体層と前記正極集電体層上に配置された正極活物質層からなる正極層と、負極集電体層と前記負極集電体層上に配置された負極活物質層からなる負極層と、前記正極活物質層と前記負極活物質層とが固体電解質層を介して積層されたリチウムイオン二次電池において、
前記正極活物質層は正極活物質を含み、前記負極活物質層は負極活物質を含み、前記固体電解質層は固体電解質を含み、
前記正極活物質層又は前記負極活物質層と前記固体電解質層とが接する少なくとも１つの接触面において、
前記正極活物質又は前記負極活物質を構成する元素の少なくとも一部と前記固体電解質を構成する元素の少なくとも一部からなる中間化合物を、前記正極活物質又は前記負極活物質と前記固体電解質が接触する接触面に有し、
前記接触面は、前記正極層又は前記負極層と前記固体電解質層が直接接合する領域Ｌ１と、前記正極層又は負極層と前記固体電解質層が前記中間化合物を介して接合する領域Ｌ２を持ち、
前記Ｌ１とＬ２の関係がＬ１＞Ｌ２かつＬ２＞０であり、
前記正極活物質又は負極活物質のいずれかがリン酸バナジウムリチウムを含むことを特徴とする、
リチウムイオン二次電池。 A positive electrode layer comprising a positive electrode current collector layer, a positive electrode active material layer disposed on the positive electrode current collector layer, and a negative electrode current collector layer and a negative electrode active material layer disposed on the negative electrode current collector layer. In a lithium ion secondary battery in which a negative electrode layer, the positive electrode active material layer, and the negative electrode active material layer are stacked via a solid electrolyte layer,
The positive electrode active material layer includes a positive electrode active material, the negative electrode active material layer includes a negative electrode active material, the solid electrolyte layer includes a solid electrolyte,
In at least one contact surface where the positive electrode active material layer or the negative electrode active material layer and the solid electrolyte layer are in contact with each other,
An intermediate compound consisting of at least part of the elements constituting the positive electrode active material or the negative electrode active material and at least part of the elements constituting the solid electrolyte is brought into contact with the positive electrode active material or the negative electrode active material and the solid electrolyte. On the contact surface
The contact surface has a region L1 where the positive electrode layer or the negative electrode layer and the solid electrolyte layer are directly bonded, and a region L2 where the positive electrode layer or the negative electrode layer and the solid electrolyte layer are bonded via the intermediate compound,
The relationship between L1 and L2 is L1> L2 and L2> 0,
Either the positive electrode active material or the negative electrode active material contains lithium vanadium phosphate,
Lithium ion secondary battery. 前記中間化合物が金属リン酸塩、金属ピロリン酸塩、金属バナジン酸塩の少なくとも１つからなる化合物であることを特徴とする請求項１に記載のリチウムイオン二次電池。   The lithium ion secondary battery according to claim 1, wherein the intermediate compound is a compound composed of at least one of a metal phosphate, a metal pyrophosphate, and a metal vanadate. 前記正極活物質及び負極活物質は共にリン酸バナジウムリチウムを含むことを特徴とする請求項１または２に記載のリチウムイオン二次電池。   The lithium ion secondary battery according to claim 1, wherein both the positive electrode active material and the negative electrode active material contain lithium vanadium phosphate. 前記固体電解質が一般式Ｌｉ１＋ｘＡｌｘＴｉ２−ｘ（ＰＯ４）３（０≦ｘ≦０．６）で表される化合物であることを特徴とする請求項１〜３のいずれか一項に記載のリチウムイオン二次電池。 The solid electrolyte formula Li1 + x Al x Ti 2- x (PO 4) 3 any one of claims 1 to 3, wherein the (0 ≦ x ≦ 0.6) is a compound represented by The lithium ion secondary battery described in 1. 前記正極集電体層及び負極集電体層がＣｕを含むことを特徴とする請求項１〜４のいずれか一項に記載のリチウムイオン二次電池。   The lithium ion secondary battery according to claim 1, wherein the positive electrode current collector layer and the negative electrode current collector layer contain Cu.
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