JP2014120403A - Secondary battery - Google Patents

Secondary battery Download PDF

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JP2014120403A
JP2014120403A JP2012276267A JP2012276267A JP2014120403A JP 2014120403 A JP2014120403 A JP 2014120403A JP 2012276267 A JP2012276267 A JP 2012276267A JP 2012276267 A JP2012276267 A JP 2012276267A JP 2014120403 A JP2014120403 A JP 2014120403A
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positive electrode
active material
material layer
electrode layer
current collector
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JP6028916B2 (en
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Koji Kitada
耕嗣 北田
Yoshio Tagawa
嘉夫 田川
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Mitsubishi Motors Corp
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Mitsubishi Motors Corp
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Priority to CN201310653412.0A priority patent/CN103872374B/en
Priority to KR1020130153411A priority patent/KR101588264B1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery having high output performance while retaining capacity.SOLUTION: A secondary battery includes a collector foil 33 and an electrode body having an active material layer provided on the collector foil, and uses metal ions of metal included in the active material layer, as mobile ions. The active material layer comprises at least two layers. A first active material layer (a first positive electrode layer 31) on a collector foil side has higher capacity than a second active material layer (a second positive electrode layer 32) on the other side. The second active material layer has higher output than the first active material layer, and is electrically connected to the collector foil via a cut and raised portion 34 functioning as a conductive member.

Description

本発明は二次電池に関する。   The present invention relates to a secondary battery.

従来、電気自動車やプラグインハイブリッド電気自動車等の電動車両に搭載されているモーター駆動用のバッテリとして、リチウムイオン二次電池等の二次電池が用いられている。リチウムイオン二次電池は、充放電時にリチウムイオンが可動イオンとして電極間を移動するものであり、充放電時に化学反応が生じないので電解液の濃度が変化しない。このように充電時に金属イオンが可動イオンとして電解液を移動するリチウムイオン二次電池は、ロッキングチェアー型の二次電池と呼ばれる。   2. Description of the Related Art Conventionally, secondary batteries such as lithium ion secondary batteries have been used as motor driving batteries mounted on electric vehicles such as electric vehicles and plug-in hybrid electric vehicles. In the lithium ion secondary battery, lithium ions move between the electrodes as movable ions during charge / discharge, and no chemical reaction occurs during charge / discharge, so the concentration of the electrolyte does not change. A lithium ion secondary battery in which metal ions move as movable ions during charging in this way is called a rocking chair type secondary battery.

ところで、電動車両に搭載される二次電池は、車両を登坂、加速及び低温駆動させるための大電流出力に応える優れた出力特性や、急速充電や回生時の大電流入力に応える優れた入力特性に加え、長時間駆動可能な高いエネルギー容量特性が求められる。   By the way, the secondary battery mounted on an electric vehicle has excellent output characteristics that respond to large current output for climbing, accelerating, and driving at low temperatures, and excellent input characteristics that respond to large current input during rapid charging and regeneration. In addition, high energy capacity characteristics that can be driven for a long time are required.

このようなリチウムイオン二次電池の入出力特性を向上させるために、正極と負極の抵抗比が所定範囲になるように電極材料を調整したリチウムイオン二次電池が提案されている（例えば、特許文献１参照）。   In order to improve the input / output characteristics of such a lithium ion secondary battery, a lithium ion secondary battery in which the electrode material is adjusted so that the resistance ratio between the positive electrode and the negative electrode falls within a predetermined range has been proposed (for example, patents). Reference 1).

特開２０１１−１８７１８６号公報JP 2011-187186 A

しかしながら、このようなリチウムイオン二次電池を電気自動車に搭載したとしても、アクセルが全開となるなど高出力が要求された場合、十分な出力を発揮できない虞がある。他方で、リチウムイオン二次電池の出力性能のみを向上させるとすれば、リチウムイオン二次電池の容量が低下して、走行距離が短くなってしまう。   However, even if such a lithium ion secondary battery is mounted on an electric vehicle, there is a possibility that sufficient output cannot be achieved when high output is required such as when the accelerator is fully opened. On the other hand, if only the output performance of the lithium ion secondary battery is improved, the capacity of the lithium ion secondary battery is reduced and the travel distance is shortened.

なお、このような問題は特に車載用のリチウムイオン二次電池で顕著な問題であるが、車載用の二次電池に限定されるものではなく、リチウムイオン二次電池に限定されるものでもない。   In addition, although such a problem is a remarkable problem especially in a vehicle-mounted lithium ion secondary battery, it is not limited to a vehicle-mounted secondary battery, It is not limited to a lithium ion secondary battery. .

そこで、本発明の課題は、上記従来技術の問題点を解決することにあり、高い出力性能を有する二次電池を提供しようとするものである。   Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to provide a secondary battery having high output performance.

本発明の二次電池は、集電箔と、該集電箔に設けられた活物質層を有する電極体を備え、前記活物質層に含まれる金属の金属イオンを可動イオンとする二次電池であって、前記活物質層は前記集電箔側の第１活物質層と、前記集電箔とは他方側の第２活物質層の少なくとも２層からなり、前記第２活物質層は、前記第１活物質層とは異なる特性を有し、かつ、導電部材により前記集電箔と接続されていることを特徴とする。   The secondary battery according to the present invention includes a current collector foil and an electrode body having an active material layer provided on the current collector foil, and a secondary battery using metal ions contained in the active material layer as movable ions. The active material layer includes at least two layers of a first active material layer on the current collector foil side and a second active material layer on the other side of the current collector foil, and the second active material layer includes: The first active material layer has characteristics different from those of the first active material layer and is connected to the current collector foil by a conductive member.

本発明では、第２活物質層が集電箔と接続されているため、第２活物質層と集電箔との間に第１活物質層が介在しているとしても、出力性能の低下を抑制することが可能である。また、第１活物質層と第２活物質層とが異なる特性を有していることから、互いに特性を補うことができる。   In the present invention, since the second active material layer is connected to the current collector foil, the output performance is reduced even if the first active material layer is interposed between the second active material layer and the current collector foil. Can be suppressed. In addition, since the first active material layer and the second active material layer have different characteristics, the characteristics can be supplemented with each other.

前記集電箔側の第１活物質層は、他方側の第２活物質層よりも高容量であり、前記第２活物質層は、前記第１活物質層よりも高出力であることが好ましい。このように構成されていることで、容量を保持しつつ、出力を向上させることができる。   The first active material layer on the current collector foil side has a higher capacity than the second active material layer on the other side, and the second active material layer has a higher output than the first active material layer. preferable. With this configuration, the output can be improved while maintaining the capacity.

本発明の好ましい実施形態としては、前記活物質層は、正極を構成する正極活物質が含有された正極活物質層であることが挙げられる。   As a preferred embodiment of the present invention, the active material layer may be a positive electrode active material layer containing a positive electrode active material constituting a positive electrode.

本発明の好ましい実施形態としては、前記導電部材は、前記集電箔とは同一の材料から構成されていることが挙げられる。   As preferable embodiment of this invention, it is mentioned that the said electroconductive member is comprised from the same material as the said current collection foil.

前記導電部材は、前記集電箔が切り起こされてなる切り起こし部であることが好ましい。これにより、簡易に、かつ確実に集電箔と第２活物質層とを接続する導電部材を設けることができる。   The conductive member is preferably a cut-and-raised part formed by cutting and raising the current collector foil. Thereby, the electrically-conductive member which connects a current collection foil and a 2nd active material layer easily and reliably can be provided.

本発明の好ましい実施形態としては、前記導電部材は、前記集電箔とは異なる材料から構成されていることが挙げられる。   As preferable embodiment of this invention, it is mentioned that the said electroconductive member is comprised from the material different from the said current collection foil.

また、本発明の好ましい実施形態として、前記導電部材は、前記第２活物質層との接触面積が前記集電箔との接触面積に比べて大きくなるように構成されていることが挙げられる。   Moreover, as preferable embodiment of this invention, it is mentioned that the said electrically-conductive member is comprised so that a contact area with a said 2nd active material layer may become large compared with a contact area with the said current collection foil.

本発明の二次電池によれば、容量を保持しつつ、高い出力性能を有するという優れた効果を奏し得る。   According to the secondary battery of the present invention, it is possible to achieve an excellent effect of having high output performance while maintaining capacity.

実施形態１にかかる二次電池を示す斜視図である。1 is a perspective view showing a secondary battery according to Embodiment 1. FIG. 実施形態１にかかる二次電池の（１）は図１のＡ−Ａ’線での断面図であり、（２）は図１のＢ−Ｂ’線での断面図である。(1) of the secondary battery concerning Embodiment 1 is sectional drawing in the A-A 'line of FIG. 1, (2) is sectional drawing in the B-B' line of FIG. 実施形態１にかかる二次電池の（１）は電極体の一部拡大断面図であり、（２）は正極活物質層の一部拡大断面図である。(1) of the secondary battery concerning Embodiment 1 is a partially expanded sectional view of an electrode body, (2) is a partially expanded sectional view of a positive electrode active material layer. 実施形態２にかかる正極活物質層の（１）は製造過程を示す模式図であり、（２）は一部拡大断面図である。(1) of the positive electrode active material layer concerning Embodiment 2 is a schematic diagram which shows a manufacture process, (2) is a partial expanded sectional view. 実施形態３にかかる正極活物質層の（１）は製造過程を示す模式図であり、（２）は一部拡大断面図である。(1) of the positive electrode active material layer concerning Embodiment 3 is a schematic diagram which shows a manufacture process, (2) is a partial expanded sectional view. 他の実施形態にかかる正極活物質層の一部拡大断面図である。It is a partial expanded sectional view of the positive electrode active material layer concerning other embodiment. 他の実施形態にかかる正極活物質層の一部拡大断面図である。It is a partial expanded sectional view of the positive electrode active material layer concerning other embodiment. 他の実施形態にかかる正極活物質層の一部拡大断面図である。It is a partial expanded sectional view of the positive electrode active material layer concerning other embodiment. 他の実施形態にかかる正極活物質層の（１）は製造過程を示す模式図であり、（２）は一部拡大断面図である。(1) of the positive electrode active material layer concerning other embodiment is a schematic diagram which shows a manufacture process, (2) is a partially expanded sectional view.

（実施形態１）
本発明の第１の実施形態について、図１、２を用いて説明する。図１は、本実施形態にかかる二次電池（リチウムイオン二次電池）を示す斜視図であり、図２（１）は図１のＡ−Ａ’線での断面図であり、図２（２）は図１のＢ−Ｂ’線での断面図である。 (Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a secondary battery (lithium ion secondary battery) according to the present embodiment, FIG. 2 (1) is a cross-sectional view taken along line AA ′ of FIG. 2) is a sectional view taken along line BB ′ of FIG.

本発明の二次電池１は、例えば電動車両に搭載されるものである。二次電池１は、略直方体形状のケース１１と、ケース１１の開口部に配されてケース１１を封止する蓋部１２とを備える。図２に示すように、ケース１１内には電極体１３が収納されている。また、ケース１１内部には電解液１４が注入されており、電極体１３は電解液１４に浸漬されている。電極体１３は、セパレータを介して正極板及び負極板が積層されたものを巻回して形成されたものであり、積層方向は、図中横方向となっている。   The secondary battery 1 of the present invention is mounted on, for example, an electric vehicle. The secondary battery 1 includes a substantially rectangular parallelepiped case 11 and a lid 12 that is disposed in an opening of the case 11 and seals the case 11. As shown in FIG. 2, an electrode body 13 is accommodated in the case 11. An electrolyte solution 14 is injected into the case 11, and the electrode body 13 is immersed in the electrolyte solution 14. The electrode body 13 is formed by winding a laminate of a positive electrode plate and a negative electrode plate with a separator interposed therebetween, and the lamination direction is a horizontal direction in the figure.

電解液１４としては、通常用いられる溶媒、例えば環状炭酸エステルであるエチレンカーボネートやプロピレンカーボネートと、鎖状炭酸エステルであるジメチルカーボネートやエチルメチルカーボネート、ジエチルカーボネートとの混合溶液に六フッ化リン酸リチウム（ＬｉＰＦ６）を１リットル当たり１モル濃度程度溶解した有機電解液が挙げられる。 As the electrolytic solution 14, lithium hexafluorophosphate is mixed with a commonly used solvent, for example, a mixed solution of cyclic carbonates such as ethylene carbonate and propylene carbonate and chain carbonates such as dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. An organic electrolytic solution in which (LiPF 6 ) is dissolved at a molar concentration of about 1 mol per liter can be mentioned.

蓋部１２には、正極端子１５と負極端子１６とが設けられている。この正極端子１５には、正極集電部１７が接続する。また、負極端子１６には負極集電部１８が接続する。正極集電部１７及び負極集電部１８は、それぞれ電極体１３の正極板及び負極板に接続する。即ち、正極板と正極集電部１７と正極端子１５とは互いに電気的に接続されている。また、負極板と負極集電部１８と負極端子１６とは互いに電気的に接続されている。   The lid portion 12 is provided with a positive electrode terminal 15 and a negative electrode terminal 16. The positive electrode current collector 17 is connected to the positive electrode terminal 15. The negative electrode current collector 18 is connected to the negative electrode terminal 16. The positive electrode current collector 17 and the negative electrode current collector 18 are connected to the positive electrode plate and the negative electrode plate of the electrode body 13, respectively. That is, the positive electrode plate, the positive electrode current collector 17 and the positive electrode terminal 15 are electrically connected to each other. The negative electrode plate, the negative electrode current collector 18 and the negative electrode terminal 16 are electrically connected to each other.

電極体１３は、セパレータを介して設けられた正極板と負極板とが巻回されて構成されている。図３（１）に示すように、電極体１３は、セパレータ２１を介して設けられた正極板２２及び負極板２３からなる。正極板２２は、正極集電板２４と、正極集電板２４の両面に設けられ、それぞれ正極活物質を含有する正極活物質層２５とからなる。負極板２３は、負極集電板２６と、負極集電板２６の両面に設けられ、それぞれ負極活物質を含有する負極活物質層２７とからなる。   The electrode body 13 is configured by winding a positive electrode plate and a negative electrode plate provided via a separator. As shown in FIG. 3 (1), the electrode body 13 includes a positive electrode plate 22 and a negative electrode plate 23 provided via a separator 21. The positive electrode plate 22 includes a positive electrode current collector plate 24 and a positive electrode active material layer 25 that is provided on both surfaces of the positive electrode current collector plate 24 and contains a positive electrode active material. The negative electrode plate 23 includes a negative electrode current collector plate 26 and a negative electrode active material layer 27 that is provided on both surfaces of the negative electrode current collector plate 26 and contains a negative electrode active material.

負極活物質層２７が含有する負極活物質としては、負極に通常用いられる活物質、例えば黒鉛、ソフトカーボン又はハードカーボン等の非晶質炭素材料を挙げることができる。また、黒鉛は人造黒鉛であっても天然黒鉛であっても良い。また、Ｌｉ４Ｔｉ５Ｏ１２等の酸化物系負極材料や、Ａｌ、Ｓｉ、Ｇｅ、Ｓｎ等を含みリチウムイオンとの可逆な電気化学反応によりＬｉもしくはＬｉイオンに対して０ボルト近くでリチウム合金となりうるような合金系負極材料を用いることができる。さらに、本発明に適用可能な負極活物質はこれに限定されず、負極における電池反応を生じるものであればよい。例えば、その他の金属リチウム、金属酸化物、金属硫化物、金属窒化物等も用いることができる。金属酸化物としては、例えばスズ酸化物やケイ素酸化物などの不可逆性容量をもつものでもよい。 Examples of the negative electrode active material contained in the negative electrode active material layer 27 include active materials usually used for negative electrodes, such as amorphous carbon materials such as graphite, soft carbon, and hard carbon. The graphite may be artificial graphite or natural graphite. In addition, an oxide-based negative electrode material such as Li 4 Ti 5 O 12, or a lithium alloy containing Al, Si, Ge, Sn, etc. and having a reversible electrochemical reaction with lithium ions at nearly 0 volts relative to Li or Li ions An alloy negative electrode material that can be used can be used. Furthermore, the negative electrode active material applicable to the present invention is not limited to this, and any material that causes a battery reaction in the negative electrode may be used. For example, other metal lithium, metal oxide, metal sulfide, metal nitride, etc. can be used. As a metal oxide, what has irreversible capacity | capacitance, such as a tin oxide and a silicon oxide, for example may be used.

さらにまた、負極活物質層２７には、アセチレンブラック等の導電性向上剤、電解質（例えば、リチウム塩（支持電解質）、イオン伝導性ポリマー等）が含まれていてもよい。また、イオン伝導性ポリマーが含まれる場合には、前記ポリマーを重合させるための重合開始剤が含まれてもよい。   Furthermore, the negative electrode active material layer 27 may contain a conductivity improver such as acetylene black and an electrolyte (for example, a lithium salt (supporting electrolyte), an ion conductive polymer, etc.). When an ion conductive polymer is included, a polymerization initiator for polymerizing the polymer may be included.

正極活物質層２５について図３（２）を用いて詳細に説明する。正極活物質層２５は、それぞれ、正極集電板２４に形成された第１正極層（第１活物質層）３１及び第１正極層３１に形成された第２正極層（第２活物質層）３２とからなる。第１正極層３１は、第２正極層３２に比べて高容量であるように構成されている。また、第２正極層３２は、第１正極層３１に比べて高出力となるように構成されている。   The positive electrode active material layer 25 will be described in detail with reference to FIG. The positive electrode active material layer 25 includes a first positive electrode layer (first active material layer) 31 formed on the positive electrode current collector plate 24 and a second positive electrode layer (second active material layer) formed on the first positive electrode layer 31, respectively. ) 32. The first positive electrode layer 31 is configured to have a higher capacity than the second positive electrode layer 32. The second positive electrode layer 32 is configured to have a higher output than the first positive electrode layer 31.

第１正極層３１及び第２正極層３２は、第１正極層３１は第２正極層３２に比べて高容量であるように、かつ、第２正極層３２は第１正極層３１に比べて高出力となるように構成されていればどのような構成でもよいが、活物質の出力特性及び容量特性と、活物質の平均粒径、各層厚みを考慮して適宜設定すればよい。   The first positive electrode layer 31 and the second positive electrode layer 32 are configured such that the first positive electrode layer 31 has a higher capacity than the second positive electrode layer 32, and the second positive electrode layer 32 is higher than the first positive electrode layer 31. Any configuration may be used as long as it is configured to have a high output, but it may be appropriately set in consideration of the output characteristics and capacity characteristics of the active material, the average particle diameter of the active material, and the thickness of each layer.

正極活物質について説明する。本実施形態では第２正極層３２としては、ニッケル酸リチウムを含有し、第１正極層３１としてはマンガン酸リチウムを有するものである。このような活物質から各層を構成することで、簡易に第１正極層３１は第２正極層３２に比べて高容量であるように、かつ、第２正極層３２は第１正極層３１に比べて高出力となるように構成することができる。   The positive electrode active material will be described. In the present embodiment, the second positive electrode layer 32 contains lithium nickelate, and the first positive electrode layer 31 has lithium manganate. By constituting each layer from such an active material, the first positive electrode layer 31 can easily have a higher capacity than the second positive electrode layer 32, and the second positive electrode layer 32 is connected to the first positive electrode layer 31. It can be configured to have a higher output than that.

各層を構成する正極活物質はこれに限定されるものではない。例えば、以下に記載する正極活物質の中から出力特性及び容量特性に鑑みて、第２正極層３２が第１正極層３１よりも高出力であり、かつ、第１正極層３１が第２正極層３２よりも高容量となるようにそれぞれ選択してもよい。   The positive electrode active material constituting each layer is not limited to this. For example, in view of output characteristics and capacity characteristics among the positive electrode active materials described below, the second positive electrode layer 32 has a higher output than the first positive electrode layer 31, and the first positive electrode layer 31 is the second positive electrode. Each may be selected so as to have a higher capacity than the layer 32.

正極活物質としては、スピネル型の金属酸化物及び金属化合物、リン酸塩型の金属酸化物などが挙げられる。層状構造型の金属酸化物としては、リチウムニッケル系複合酸化物、リチウムコバルト系複合酸化物、三元系複合酸化物（ＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２）が挙げられる。リチウムニッケル系複合酸化物としては、好ましくはニッケル酸リチウム（ＬｉＮｉＯ２）が挙げられる。リチウムコバルト系複合酸化物としては、好ましくはコバルト酸リチウム（ＬｉＣｏＯ２）が挙げられる。スピネル型の金属酸化物としては、マンガン酸リチウム（ＬｉＭｎ２Ｏ４）等のリチウムマンガン系複合酸化物が挙げられる。リン酸塩型の金属酸化物としては、リン酸鉄リチウム（ＬｉＦｅＰＯ４）、リン酸マンガンリチウム（ＬｉＭｎＰＯ４）等が挙げられる。 Examples of the positive electrode active material include spinel-type metal oxides and metal compounds, and phosphate-type metal oxides. Examples of the layered structure type metal oxide include lithium nickel composite oxide, lithium cobalt composite oxide, and ternary composite oxide (LiCo 1/3 Ni 1/3 Mn 1/3 O 2 ). The lithium-nickel-based composite oxide, and the like, preferably a lithium nickelate (LiNiO 2). Examples of the lithium cobalt composite oxide, and preferably lithium cobalt oxide (LiCoO 2). Examples of the spinel-type metal oxide include lithium manganese complex oxides such as lithium manganate (LiMn 2 O 4 ). Examples of the phosphate metal oxide include lithium iron phosphate (LiFePO 4 ) and lithium manganese phosphate (LiMnPO 4 ).

これらの正極活物質に関し、容量特性が高いか否かは、例えば、活物質の理論容量に基づき判断することができる。例えば、ＬｉＣｏＯ２の理論容量は２７４ｍＡｈ／ｇ、ＬｉＮｉＯ２の理論容量は２７４ｍＡｈ／ｇ、ＬｉＭｎ２Ｏ４の理論容量は１４８ｍＡｈ／ｇ、ＬｉＦｅＰＯ４の理論容量は１７０ｍＡｈ／ｇである。ＬｉＣｏＯ２及びＬｉＮｉＯ２は、ＬｉＭｎ２Ｏ４及びＬｉＦｅＰＯ４と比較して理論容量が高いので、相対的に高容量の特性を有するものと判断できる。 Whether or not these positive electrode active materials have high capacity characteristics can be determined based on, for example, the theoretical capacity of the active material. For example, LiCoO 2 has a theoretical capacity of 274 mAh / g, LiNiO 2 has a theoretical capacity of 274 mAh / g, LiMn 2 O 4 has a theoretical capacity of 148 mAh / g, and LiFePO 4 has a theoretical capacity of 170 mAh / g. Since LiCoO 2 and LiNiO 2 have a higher theoretical capacity than LiMn 2 O 4 and LiFePO 4 , it can be determined that they have relatively high capacity characteristics.

また、活物質を出力特性及び容量特性に鑑みて選択し、かつ、以下説明する活物質の粒径や導電助剤の配合を調整して、第２正極層３２が第１正極層３１よりも高出力であり、かつ、第１正極層３１が第２正極層３２よりも高容量となるように構成しても良い。   In addition, the active material is selected in view of the output characteristics and capacity characteristics, and the particle size of the active material and the blending of the conductive assistant described below are adjusted so that the second positive electrode layer 32 is more than the first positive electrode layer 31. The first positive electrode layer 31 may have a higher output and a higher capacity than the second positive electrode layer 32.

第２正極層３２に含有される活物質の平均粒径は、０．１〜１００μｍであることが好ましく、より好ましくは３０μｍ以下であることが挙げられる。この範囲であることで、活物質の総表面積が増大し、これにより反応性が向上して出力が高くなるからである。第２正極層３２は、さらに導電助剤を含む。導電助剤としては、アセチレンブラックやケッチェンブラックが挙げられる。本実施形態では、アセチレンブラックを含有する。第２正極層３２には、導電助剤が３〜３０質量％含有されていることが好ましく、より好ましくは導電助剤が２０質量％以上となることが挙げられる。導電助剤を３〜３０質量％含んでいることで、第２正極層３２の出力特性を向上させることができる。第２正極層３２は、その厚みは１〜１００μｍである。   The average particle size of the active material contained in the second positive electrode layer 32 is preferably 0.1 to 100 μm, and more preferably 30 μm or less. By being in this range, the total surface area of the active material is increased, thereby improving the reactivity and increasing the output. The second positive electrode layer 32 further includes a conductive additive. Examples of the conductive assistant include acetylene black and ketjen black. In this embodiment, acetylene black is contained. The second positive electrode layer 32 preferably contains 3 to 30% by mass of a conductive additive, more preferably 20% by mass or more. By containing 3 to 30% by mass of the conductive additive, the output characteristics of the second positive electrode layer 32 can be improved. The second positive electrode layer 32 has a thickness of 1 to 100 μm.

第１正極層３１に含有される正極活物質の平均粒径は、０．１〜２００μｍであることが好ましく、より好ましくは３０μｍよりも大きいことが挙げられる。この範囲であることで、容量特性を向上させることが可能である。第２正極層３２は、さらに導電助剤を含んでいてもよい。本実施形態では、導電助剤としてアセチレンブラックを含有する。導電助剤は、０〜２５質量％、好ましくは２０質量％未満含んでいることが好ましい。導電助剤を０〜２５質量％含んでいることで容量を低下させずに第１正極層３１の容量特性を向上させることができる。第１正極層３１は、その厚みが５〜３００μｍであり、好ましくは１００μｍよりも厚いことが挙げられる。   The average particle diameter of the positive electrode active material contained in the first positive electrode layer 31 is preferably 0.1 to 200 μm, more preferably larger than 30 μm. Within this range, it is possible to improve the capacity characteristics. The second positive electrode layer 32 may further contain a conductive additive. In this embodiment, acetylene black is contained as a conductive additive. It is preferable that the conductive assistant is contained in an amount of 0 to 25% by mass, preferably less than 20% by mass. By containing 0 to 25% by mass of the conductive additive, the capacity characteristic of the first positive electrode layer 31 can be improved without reducing the capacity. The first positive electrode layer 31 has a thickness of 5 to 300 μm, preferably thicker than 100 μm.

これらの活物質の出力特性及び容量特性と、活物質の平均粒径、導電助剤の配合や層厚みを考慮して、第２正極層３２が第１正極層３１よりも高出力であり、かつ、第１正極層３１が第２正極層３２よりも高容量とする。即ち、第２正極層３２が第１正極層３１よりも高出力であり、かつ、第１正極層３１が第２正極層３２よりも高容量となるように、第２正極層３２の活物質はその平均粒径を小さくすればよいし、第１正極層３１の活物質はその平均粒径を大きくすればよい。また、第２正極層３２が第１正極層３１よりも高出力であり、かつ、第１正極層３１が第２正極層３２よりも高容量となるように、容量性能を高める場合には厚みを厚く、出力性能を高める場合には厚みを薄くすればよい。   The second positive electrode layer 32 has a higher output than the first positive electrode layer 31 in consideration of the output characteristics and capacity characteristics of these active materials, the average particle diameter of the active material, the blending of the conductive auxiliary agent and the layer thickness, In addition, the first positive electrode layer 31 has a higher capacity than the second positive electrode layer 32. That is, the active material of the second positive electrode layer 32 so that the second positive electrode layer 32 has a higher output than the first positive electrode layer 31 and the first positive electrode layer 31 has a higher capacity than the second positive electrode layer 32. The average particle size may be reduced, and the active material of the first positive electrode layer 31 may be increased in average particle size. Further, when the capacity performance is increased so that the second positive electrode layer 32 has a higher output than the first positive electrode layer 31 and the first positive electrode layer 31 has a higher capacity than the second positive electrode layer 32, the thickness is increased. When the thickness is increased and the output performance is improved, the thickness may be decreased.

このように、本実施形態では、これらの活物質の出力特性及び容量特性と、活物質の平均粒径、層厚みを考慮して、第２正極層３２が第１正極層３１よりも高出力であり、かつ、第１正極層３１が第２正極層３２よりも高容量となるように第１正極層３１及び第２正極層３２を構成している。   Thus, in the present embodiment, the second positive electrode layer 32 has a higher output than the first positive electrode layer 31 in consideration of the output characteristics and capacity characteristics of these active materials, the average particle diameter of the active material, and the layer thickness. In addition, the first positive electrode layer 31 and the second positive electrode layer 32 are configured so that the first positive electrode layer 31 has a higher capacity than the second positive electrode layer 32.

なお、第２正極層３２及び第１正極層３１で同一の活物質を用いたとしても、第１正極層３１の活物質の平均粒径を小さくすることで、又は導電助剤を増やすことで、第２正極層３２の出力特性を第１正極層３１よりも向上させると共に相対的に第１正極層３１の容量特性を向上させることも可能である。   Even if the same active material is used for the second positive electrode layer 32 and the first positive electrode layer 31, it is possible to reduce the average particle size of the active material of the first positive electrode layer 31, or to increase the conductive auxiliary agent. The output characteristics of the second positive electrode layer 32 can be improved as compared with the first positive electrode layer 31, and the capacity characteristics of the first positive electrode layer 31 can be relatively improved.

本実施形態では、正極活物質層をこのような異なる特性を有する２層の正極層から構成していることで、二次電池は高出力かつ高容量を実現することができる。即ち、正極層を第１正極層３１又は第２正極層３２のみから構成するとすれば、出力特性及び容量特性のいずれかしか満足することはできないので、本実施形態では、第１正極層３１及び第２正極層３２から正極層を構成しているのである。   In this embodiment, since the positive electrode active material layer is composed of two positive electrode layers having such different characteristics, the secondary battery can achieve high output and high capacity. That is, if the positive electrode layer is composed of only the first positive electrode layer 31 or the second positive electrode layer 32, either the output characteristic or the capacity characteristic can be satisfied. The second positive electrode layer 32 constitutes the positive electrode layer.

ところで、出力時に第２正極層３２から電子を正極集電板２４側に到達させようとすれば、電子は第１正極層３１を通過しなければならず、これにより所望の出力性能を発揮できない虞があるので、これを防止する必要がある。そこで、本実施形態では、正極集電板２４を二枚の集電箔３３から構成し、各集電箔と各第２正極層３２とを導電部材により電気的に接続している。   By the way, if electrons are allowed to reach the positive electrode current collector 24 side from the second positive electrode layer 32 at the time of output, the electrons must pass through the first positive electrode layer 31, and thus the desired output performance cannot be exhibited. Since there is a possibility, it is necessary to prevent this. Therefore, in the present embodiment, the positive electrode current collector plate 24 is composed of two current collector foils 33, and each current collector foil and each second positive electrode layer 32 are electrically connected by a conductive member.

以下詳細に説明する。正極集電板２４は、二枚の集電箔３３を貼り合わせてなるものである。集電箔３３は、銅や銀など通常配線として用いることができる金属からなり、本実施形態ではアルミニウムからなる。各集電箔３３には、その一方面側にそれぞれ正極活物質層２５が設けられている。各集電箔３３には、それぞれその一部が切り起こされた切り起こし部３４が設けられている。この切り起こし部３４の先端は、第２正極層３２内に延在しており、これにより切り起こし部３４を介して集電箔３３と第２正極層３２とは電気的に接続されている。   This will be described in detail below. The positive electrode current collector plate 24 is formed by bonding two current collector foils 33 together. The current collector foil 33 is made of a metal that can be used as a normal wiring such as copper or silver, and is made of aluminum in the present embodiment. Each current collector foil 33 is provided with a positive electrode active material layer 25 on one side thereof. Each current collector foil 33 is provided with a cut-and-raised portion 34 that is partially cut and raised. The tip of the cut-and-raised part 34 extends into the second positive electrode layer 32, and the current collector foil 33 and the second positive electrode layer 32 are electrically connected via the cut-and-raised part 34. .

本実施形態では、このように切り起こし部３４が設けられていることで、第２正極層３２の出力特性をより向上させることができる。即ち、切り起こし部３４が導電部材として機能することから、出力特性の高い第２正極層３２と集電箔３３とが電気的に接続される導電経路が切り起こし部３４により形成されている。これにより、高出力が要求された場合に、第２正極層３２の電子が導電経路である切り起こし部３４を介して集電箔３３に到達することから、第２正極層３２からより応答性高く出力を得ることができる。   In the present embodiment, the output characteristics of the second positive electrode layer 32 can be further improved by providing the cut-and-raised portion 34 in this way. That is, since the cut-and-raised portion 34 functions as a conductive member, the cut-and-raised portion 34 forms a conductive path in which the second positive electrode layer 32 and the current collector foil 33 having high output characteristics are electrically connected. As a result, when high output is required, the electrons of the second positive electrode layer 32 reach the current collector foil 33 via the cut-and-raised portion 34 that is a conductive path, and thus the second positive electrode layer 32 is more responsive. High output can be obtained.

このように、本実施形態では、容量特性を保持しつつ出力特性を高めるために、高容量の第１正極層３１と高出力の第２正極層３２とを有し、かつ、第２正極層３２と集電箔３３とが電気的に接続されている。この場合に第２正極層３２に存在する電子が第１正極層３１を通過しないと集電箔３３に到達できないとすれば出力特性の高さを活かすことができないが、本実施形態では、第２正極層３２の電子は、第１正極層３１を介して集電箔３３に到達するのではなく、切り起こし部３４を介して集電箔３３に到達する。従って、電子は第１正極層３１を通過する場合よりも移動しやすい。その結果、二次電池は第２正極層３２の出力性能をより発揮することができ、高出力要求に応答することができるのである。   Thus, in the present embodiment, in order to enhance the output characteristics while maintaining the capacity characteristics, the first positive electrode layer 31 having the high capacity and the second positive electrode layer 32 having the high output are provided, and the second positive electrode layer is provided. 32 and the current collector foil 33 are electrically connected. In this case, if the electrons present in the second positive electrode layer 32 do not pass through the first positive electrode layer 31 and cannot reach the current collector foil 33, the high output characteristics cannot be utilized. The electrons of the two positive electrode layers 32 do not reach the current collector foil 33 via the first positive electrode layer 31 but reach the current collector foil 33 via the cut and raised portion 34. Therefore, electrons move more easily than when passing through the first positive electrode layer 31. As a result, the secondary battery can further exhibit the output performance of the second positive electrode layer 32 and can respond to a high output request.

二枚の集電箔３３は、本実施形態では切り起こし部３４を互いにずらして貼付したものであるが、これに限定されない。例えば、切り起こし部３４が互いに対向していても良い。   In the present embodiment, the two current collector foils 33 are obtained by sticking the cut and raised portions 34 to each other, but the present invention is not limited to this. For example, the cut and raised portions 34 may face each other.

なお、負極活物質層２７、正極活物質層２５は、それぞれさらにポリフッ化ビニリデン等のバインダーを含んでいてもよい。   Note that each of the negative electrode active material layer 27 and the positive electrode active material layer 25 may further contain a binder such as polyvinylidene fluoride.

かかる本実施形態の二次電池では、初めに切り起こし部３４が設けられた集電箔３３に対して、第１正極層３１を形成するためのスラリーを調整し、これを塗布し乾燥して第１正極層３１を形成し、その後、第２正極層３２を形成するためのスラリーを調整し、これを塗布し乾燥して第２正極層３２を形成する。乾燥時には、加熱を行っても良いし、乾燥後にプレス工程を行っても良い。この場合に切り起こし部３４はある程度の剛性を有するものであるので、スラリーを塗布したとしても倒れることはない。そして、その後第１正極層３１及び第２正極層３２を形成した二枚の集電箔３３を貼り合わせて一枚の正極板２２を形成する。このように、簡易に本実施形態にかかる構成の正極活物質層２５を形成することが可能である。   In the secondary battery of this embodiment, first, the slurry for forming the first positive electrode layer 31 is prepared for the current collector foil 33 provided with the cut-and-raised part 34, and this is applied and dried. The first positive electrode layer 31 is formed, and then the slurry for forming the second positive electrode layer 32 is prepared, and this is applied and dried to form the second positive electrode layer 32. At the time of drying, heating may be performed, or a pressing process may be performed after drying. In this case, the cut-and-raised part 34 has a certain degree of rigidity, so that even if the slurry is applied, it does not fall down. Then, the two current collector foils 33 on which the first positive electrode layer 31 and the second positive electrode layer 32 are formed are bonded together to form one positive electrode plate 22. Thus, the positive electrode active material layer 25 having the configuration according to the present embodiment can be easily formed.

（実施形態２）
上述した実施形態１では、切り起こし部３４により集電箔３３と第２正極層３２とを電気的に接続したが、本実施形態では、図４に示すように、導電部材３５Ａにより集電箔３３Ａと第２正極層３２Ａとを電気的に接続する点が異なる。なお、本実施形態では説明のためセパレータ側の集電箔及び正極活物質層は省略している。 (Embodiment 2)
In Embodiment 1 described above, the current collector foil 33 and the second positive electrode layer 32 are electrically connected by the cut-and-raised portion 34. However, in this embodiment, as shown in FIG. The difference is that 33A and the second positive electrode layer 32A are electrically connected. In the present embodiment, the current collector foil and the positive electrode active material layer on the separator side are omitted for explanation.

本実施形態では、集電箔３３Ａに第１正極層３１Ａ及び第２正極層３２Ａを形成した後に、第２正極層３２Ａの表面側から棒状の導電部材３５Ａを挿入している。導電部材３５Ａは、第１正極層３１Ａの厚さよりも長い棒状の部材である。導電部材３５Ａは、通常配線として用いられる金属、例えば銅（Ｃｕ）や銀（Ａｇ）等を用いることができる。導電部材３５Ａは剛性を有する集電箔３３Ａに接触した状態で正極内に留まる。   In this embodiment, after forming the first positive electrode layer 31A and the second positive electrode layer 32A on the current collector foil 33A, the rod-shaped conductive member 35A is inserted from the surface side of the second positive electrode layer 32A. The conductive member 35A is a rod-like member that is longer than the thickness of the first positive electrode layer 31A. For the conductive member 35A, a metal that is normally used as a wiring, such as copper (Cu) or silver (Ag), can be used. The conductive member 35A remains in the positive electrode in contact with the rigid current collector foil 33A.

本実施形態では、導電部材３５Ａは金属としたが、電気抵抗が低いものであれば、即ち通常配線として用いられるものであれば特に限定されない。例えば、集電箔３３と同一の金属からなるものであっても、異なる金属からなるものであってもよい。   In the present embodiment, the conductive member 35A is made of metal, but is not particularly limited as long as it has a low electrical resistance, that is, if it is used as a normal wiring. For example, it may be made of the same metal as the current collector foil 33 or may be made of a different metal.

このように形成された本実施形態も、二次電池は第１正極層３１Ａ及び第２正極層３２Ａという二つの異なる性能を有する正極層を有し、かつ、第２正極層３２Ａと集電箔３３Ａが導電部材３５Ａにより接続されていることから、二次電池は容量を保持しつつ、高い出力性能を有する。   In this embodiment formed in this way, the secondary battery also has two positive electrode layers having the first positive electrode layer 31A and the second positive electrode layer 32A, and the second positive electrode layer 32A and the current collector foil. Since 33A is connected by the conductive member 35A, the secondary battery has high output performance while maintaining capacity.

（実施形態３）
上述した実施形態２では、第２正極層３２Ａの表面側から棒状の導電部材３５Ａを挿入して導電部材３５Ａにより導電経路を形成したが、本実施形態では、図５に示すように、集電箔３３Ｂ側から棒状の導電部材３５Ｂを挿入して導電部材３５Ｂにより導電経路を形成する点が実施形態２とは異なる。なお、本実施形態では説明のためセパレーター側の集電箔及び正極活物質層は省略している。 (Embodiment 3)
In Embodiment 2 described above, the conductive path is formed by the conductive member 35A by inserting the rod-shaped conductive member 35A from the surface side of the second positive electrode layer 32A. However, in this embodiment, as shown in FIG. The point which inserts the rod-shaped electrically-conductive member 35B from the foil 33B side, and forms an electroconductive path | route with the electrically-conductive member 35B differs from Embodiment 2. FIG. In the present embodiment, the separator-side current collector foil and the positive electrode active material layer are omitted for the sake of explanation.

図５（１）に示すように、本実施形態では集電箔３３Ｂに第１正極層３１Ｂ及び第２正極層３２Ｂを形成した後に、集電箔３３Ｂに設けられた開口３６Ｂから棒状の導電部材３５Ｂを挿入している。導電部材３５Ｂは、実施形態２における導電部材３５Ａと同一である。そして、棒状の導電部材３５Ｂを集電箔３３Ｂに設けられた開口３６Ｂに挿入する。この場合に、開口３６Ｂは導電部材３５Ｂよりも若干径が小さく構成されている。このように構成されていることで、導電部材３５Ｂを開口３６Ｂに挿入すると導電部材３５Ｂが集電箔３３Ｂに接続することができ、導電部材３５Ｂを介して第２電極層３２Ｂと集電箔３３Ｂとが接続される。   As shown in FIG. 5 (1), in this embodiment, after forming the 1st positive electrode layer 31B and the 2nd positive electrode layer 32B in the current collection foil 33B, it is a rod-shaped electrically-conductive member from the opening 36B provided in the current collection foil 33B. 35B is inserted. The conductive member 35B is the same as the conductive member 35A in the second embodiment. Then, the rod-shaped conductive member 35B is inserted into the opening 36B provided in the current collector foil 33B. In this case, the opening 36B is configured to be slightly smaller in diameter than the conductive member 35B. With this configuration, when the conductive member 35B is inserted into the opening 36B, the conductive member 35B can be connected to the current collector foil 33B, and the second electrode layer 32B and the current collector foil 33B can be connected via the conductive member 35B. And are connected.

なお、本実施形態では、集電箔３３Ｂに開口３６Ｂを設け、この開口３６Ｂから導電部材３５Ｂを挿入したが、これに限定されない。導電部材３５Ｂを集電箔３３Ｂよりも硬い金属から構成し、これにより導電部材３５Ｂにより集電箔３３Ｂを突き破って正極活物質層内に挿入できるように構成してもよい。   In the present embodiment, the current collector foil 33B is provided with the opening 36B, and the conductive member 35B is inserted through the opening 36B. However, the present invention is not limited to this. The conductive member 35B may be made of a metal harder than the current collector foil 33B, so that the current collector foil 33B can be penetrated by the conductive member 35B and inserted into the positive electrode active material layer.

このように形成された本実施形態も、二次電池は第１正極層３１Ｂ及び第２正極層３２Ｂという二つの異なる性能を有する正極層を有し、かつ、第２正極層３２Ｂと集電箔３３Ｂが導電部材３５Ｂにより接続されていることから、二次電池は容量を保持しつつ、高い出力性能を有する。   Also in this embodiment formed in this way, the secondary battery has positive electrode layers having two different performances of the first positive electrode layer 31B and the second positive electrode layer 32B, and the second positive electrode layer 32B and the current collector foil Since 33B is connected by the conductive member 35B, the secondary battery has high output performance while maintaining capacity.

（実施形態４）
上述した実施形態３では導電部材３５Ｂは棒状であったが、本実施形態では、導電部材３５Ｃは釘形状である点が実施形態３と異なる。なお、本実施形態では説明のためセパレーター側の集電箔及び正極活物質層は省略している。 (Embodiment 4)
In the third embodiment described above, the conductive member 35B has a rod shape, but in the present embodiment, the conductive member 35C is different from the third embodiment in that the conductive member 35C has a nail shape. In the present embodiment, the separator-side current collector foil and the positive electrode active material layer are omitted for the sake of explanation.

本実施形態では、導電部材３５Ｃは、棒状の体部と体部よりも径の大きい頭部とからなり、この導電部材３５Ｃの頭部は、集電箔３３Ｃの開口３６Ｃを介して第１正極層３１Ｃ側へ挿入される場合に、ストッパーとして機能するものである。このように構成することで、より導電部材３５Ｃが集電箔３３Ｃと接触しやすく、導電部材として機能しやすい。   In the present embodiment, the conductive member 35C includes a rod-shaped body portion and a head portion having a larger diameter than the body portion, and the head portion of the conductive member 35C passes through the opening 36C of the current collector foil 33C. When inserted into the layer 31C side, it functions as a stopper. By comprising in this way, 35 C of electrically conductive members are easy to contact with the current collector foil 33C, and it is easy to function as a electrically conductive member.

このように形成された本実施形態も、二次電池は第１正極層３１Ｃ及び第２正極層３２Ｃという二つの異なる性能を有する正極層を有し、かつ、第２正極層３２Ｃと集電箔３３Ｃが導電部材３５Ｃにより接続されていることから、二次電池は容量を保持しつつ、高い出力性能を有する。   In this embodiment formed in this way, the secondary battery also has positive electrode layers having two different performances of the first positive electrode layer 31C and the second positive electrode layer 32C, and the second positive electrode layer 32C and the current collector foil Since 33C is connected by the conductive member 35C, the secondary battery has high output performance while maintaining capacity.

（他の実施形態）
上述した切り起こし部３４や、導電部材３５Ａ〜３５Ｃはその形状が限定されるものではない。例えば、以下説明する図７、図８に示す実施形態では、導電部材は、第２活物質層との接触面積が集電箔との接触面積に比べて大きくなるように構成されているものである。 (Other embodiments)
The shapes of the cut and raised portion 34 and the conductive members 35A to 35C described above are not limited. For example, in the embodiments shown in FIGS. 7 and 8 described below, the conductive member is configured such that the contact area with the second active material layer is larger than the contact area with the current collector foil. is there.

図７に示すように、導電部材３５Ｄは、その集電箔３３Ｄに対する先端側が複数に分岐しているものであってもよい。この場合は、より出力特性を高めることができる。さらにまた、図８に示すように導電部材３５Ｅは、集電箔３３Ｅに対するその基端側が尖端部となっていてもよい。このように導電部材３５Ｅの先端を尖端部とすることで、さらに挿入しやすい。   As shown in FIG. 7, the conductive member 35 </ b> D may have a plurality of branched ends on the current collecting foil 33 </ b> D. In this case, the output characteristics can be further improved. Furthermore, as shown in FIG. 8, the conductive member 35E may have a pointed end on the base end side with respect to the current collector foil 33E. Thus, it is easier to insert the conductive member 35E by making the tip of the conductive member 35E a pointed end.

また、導電部材の正極活物質層２５への導入方法は、上述したものに限定されない。例えば、図９（１）に示すように予めスラリー中に導電部材３５Ｆを混在させてこれを塗布し、乾燥時にこの導電部材３５Ｆが起立するようにしてもよい。導電部材３５Ｆを起立させるには、例えば磁石などで導電部材３５Ｆを起立させてもよいし、乾燥時にスラリーの蒸発に伴って起立するような形状としていてもよい。   The method for introducing the conductive member into the positive electrode active material layer 25 is not limited to the above-described method. For example, as shown in FIG. 9 (1), the conductive member 35F may be mixed in the slurry in advance and applied, and the conductive member 35F may stand up during drying. In order to erect the conductive member 35F, for example, the conductive member 35F may be erected with a magnet or the like, or may be shaped to elongate as the slurry evaporates during drying.

もちろん、導電部材３５Ｃの釘形状を変形させることや、導電部材３５Ｄ，３５Ｅの分岐数や分岐方向を変更することも可能である。   Of course, it is also possible to change the nail shape of the conductive member 35C, and to change the number of branches and the branch direction of the conductive members 35D and 35E.

上述した実施形態では、二次電池としてリチウムイオン電池を用いて説明したが、これに限定されない。金属イオンを可動イオンとするロッキングチェアー型の二次電池であればよい。このようなロッキングチェアー型の二次電池としては、他にナトリウムイオン電池等が挙げられる。   In the above-described embodiment, the lithium ion battery is used as the secondary battery, but the present invention is not limited to this. Any rocking chair type secondary battery using metal ions as movable ions may be used. Examples of such rocking chair type secondary batteries include sodium ion batteries.

上述した実施形態では、集電箔３３Ａ〜３３Ｅの一方面にのみ導電部材３５Ａ〜３５Ｅが存在するように設けられたが、これに限定されない。集電箔３３Ａ〜３３Ｅの両面に亘って導電部材３５Ａ〜３５Ｅが存在するように設けても良い。   In the embodiment described above, the conductive members 35A to 35E are provided only on one surface of the current collector foils 33A to 33E. However, the present invention is not limited to this. You may provide so that electroconductive member 35A-35E may exist over both surfaces of current collection foil 33A-33E.

上述した実施形態では、第１正極層３１及び第２正極層３２を積層したが、これに限定されない。第１正極層３１及び第２正極層３２の間に密着層を形成してもよいし、また、第１正極層３１と集電箔３３との間に密着層を形成してもよい。また、第２正極層３２の上にさらに別の表層を設けることも可能である。   In the embodiment described above, the first positive electrode layer 31 and the second positive electrode layer 32 are stacked, but the present invention is not limited to this. An adhesion layer may be formed between the first positive electrode layer 31 and the second positive electrode layer 32, or an adhesion layer may be formed between the first positive electrode layer 31 and the current collector foil 33. It is also possible to provide another surface layer on the second positive electrode layer 32.

また、上述した実施形態では、２枚の集電箔３３から集電板を形成したが、これに限定されない。例えば、１枚の集電箔３３Ａの両面に第１正極層３１Ａ及び第２正極層３２Ａを形成した後に、両表面から導電部材３５Ａを設けても良い。   In the above-described embodiment, the current collector plate is formed from the two current collector foils 33, but the present invention is not limited to this. For example, the conductive member 35A may be provided from both surfaces after the first positive electrode layer 31A and the second positive electrode layer 32A are formed on both surfaces of the current collector foil 33A.

上述した実施形態では、第１正極層３１は第２正極層３２に比べて高容量であるように、かつ、第２正極層３２は第１正極層３１に比べて高出力となるように構成されていたが、これに限定されない。第１正極層３１と第２正極層３２とで異なる特性を有していればよい。例えば、第１正極層３１が第２正極層３２に比べて高出力であってもよい。この場合であっても、導電部材により第１正極層３１が介在しても第２正極層３２からの出力を高くすることができる。   In the above-described embodiment, the first positive electrode layer 31 has a higher capacity than the second positive electrode layer 32, and the second positive electrode layer 32 has a higher output than the first positive electrode layer 31. However, it is not limited to this. It is sufficient that the first positive electrode layer 31 and the second positive electrode layer 32 have different characteristics. For example, the first positive electrode layer 31 may have a higher output than the second positive electrode layer 32. Even in this case, the output from the second positive electrode layer 32 can be increased even if the first positive electrode layer 31 is interposed by the conductive member.

１１ ケース
１２ 蓋部
１３ 電極体
１４ 電解液
１５ 正極端子
１６ 負極端子
１７ 正極集電部
１８ 負極集電部
２１ セパレータ
２２ 正極板
２３ 負極板
２４ 正極集電板
２５ 正極活物質層
２６ 負極集電板
２７ 負極活物質層
３１ 第１正極層
３２ 第２正極層
３３ 集電箔
３４ 切り起こし部
３５Ａ〜３５Ｅ 導電部材
３６Ｂ，３６Ｃ 開口 DESCRIPTION OF SYMBOLS 11 Case 12 Cover part 13 Electrode body 14 Electrolyte 15 Positive electrode terminal 16 Negative electrode terminal 17 Positive electrode current collector 18 Negative electrode current collector 21 Separator 22 Positive electrode plate 23 Negative electrode plate 24 Positive electrode current collector plate 25 Positive electrode active material layer 26 Negative electrode current collector plate 27 Negative electrode active material layer 31 First positive electrode layer 32 Second positive electrode layer 33 Current collector foil 34 Cut and raised portions 35A to 35E Conductive members 36B and 36C Openings

Claims (7)

集電箔と、該集電箔に設けられた活物質層を有する電極体を備え、前記活物質層に含まれる金属の金属イオンを可動イオンとする二次電池であって、
前記活物質層は前記集電箔側の第１活物質層と、前記集電箔とは他方側の第２活物質層の少なくとも２層からなり、
前記第２活物質層は、前記第１活物質層とは異なる特性を有し、かつ、導電部材により前記集電箔と接続されていることを特徴とする二次電池。 A secondary battery comprising a current collector foil and an electrode body having an active material layer provided on the current collector foil, wherein the metal ion of the metal contained in the active material layer is a movable ion,
The active material layer includes at least two layers of a first active material layer on the current collector foil side, and the current collector foil on a second active material layer on the other side,
The secondary battery, wherein the second active material layer has characteristics different from those of the first active material layer, and is connected to the current collector foil by a conductive member. 前記第１活物質層は、前記第２活物質層よりも高容量であり、
前記第２活物質層は、前記第１活物質層よりも高出力であることを特徴とする請求項１記載の二次電池。 The first active material layer has a higher capacity than the second active material layer,
The secondary battery according to claim 1, wherein the second active material layer has a higher output than the first active material layer. 前記活物質層は、正極を構成する正極活物質が含有された正極活物質層であることを特徴とする請求項１又は２記載の二次電池。   The secondary battery according to claim 1, wherein the active material layer is a positive electrode active material layer containing a positive electrode active material constituting a positive electrode. 前記導電部材は、前記集電箔とは同一の材料から構成されてい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二次電池。   The secondary battery according to claim 1, wherein the conductive member is made of the same material as that of the current collector foil. 前記導電部材は、前記集電箔が切り起こされてなる切り起こし部であることを特徴とする請求項４記載の二次電池。   The secondary battery according to claim 4, wherein the conductive member is a cut-and-raised part formed by cutting and raising the current collector foil. 前記導電部材は、前記集電箔とは異なる材料から構成されてい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二次電池。   The secondary battery according to claim 1, wherein the conductive member is made of a material different from that of the current collector foil. 前記導電部材は、前記第２活物質層との接触面積が前記集電箔との接触面積に比べて大きくなるように構成されていることを特徴とする請求項６記載の二次電池。   The secondary battery according to claim 6, wherein the conductive member is configured such that a contact area with the second active material layer is larger than a contact area with the current collector foil.
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