JP2009295400A - Nonaqueous power storage element - Google Patents
Nonaqueous power storage element Download PDFInfo
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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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Abstract
Description
この発明は、シート状の集電体上に、リチウムイオンあるいはアニオンを可逆的に担持可能な正極用電極材を塗布してなるシート状の正極と、リチウムイオンの吸蔵・放出が可能な負極用電極材を塗布してなるシート状の負極とをセパレータを介して対向配置してなる発電要素を１単位として、少なくとも１単位以上の発電要素を積層してなる電極積層体をリチウム塩を含む電解液とともに密封封止するとともに、負極にリチウム金属を起源とするリチウムイオンをあらかじめ拡散してなる非水蓄電素子に関する。 The present invention relates to a sheet-like positive electrode obtained by applying a positive electrode material capable of reversibly supporting lithium ions or anions on a sheet-like current collector, and a negative electrode capable of inserting and extracting lithium ions. An electrode stack comprising at least one unit of power generation elements laminated with a power generation element formed by opposing a sheet-like negative electrode formed by applying an electrode material with a separator interposed therebetween is an electrolysis containing a lithium salt. The present invention relates to a non-aqueous energy storage device that is hermetically sealed together with a liquid and in which lithium ions originating from lithium metal are previously diffused into a negative electrode.
上記したタイプの非水蓄電素子（以下、プレドープ型蓄電素子）は、急速充電が可能であるとともに、リチウムイオンをあらかじめ負極に吸蔵させるため、負極の電位が下がり、大きな電圧を得ることができ、高いエネルギー容量を得ることができる。そのため、風力発電の負荷平準化装置、瞬停対策装置、自動車における回生電力の蓄電用途などに利用されることが期待されている。 The above-mentioned type of non-aqueous energy storage device (hereinafter referred to as pre-doped energy storage device) is capable of rapid charging and has lithium ions stored in the negative electrode in advance, so that the potential of the negative electrode is lowered and a large voltage can be obtained. High energy capacity can be obtained. Therefore, it is expected to be used for wind power generation load leveling devices, instantaneous power failure countermeasure devices, regenerative power storage for automobiles, and the like.
従来のプレドープ型蓄電素子におけるリチウムイオンの吸蔵（プレドープ）方式には、負極の一部を削ったり、負極の上にリチウム金属を貼ったりしてリチウムイオンをプレドープする方式があるが、最近では、例えば、特許３４８５９３５号公報に記載されているように、メッシュ状の集電体を用いて形成した負極、および正極を、交互にセパレータを挟んで積層して電極積層体を構成するとともに、その積層体の外側にリチウム金属を貼った集電体を配置して負極と電気的接触を持たせることで、メッシュを通して負極にリチウムイオンをプレドープする方式がある。この方式では、リチウム金属と負極とが対向し、リチウムイオンは、負極に対して垂直方向からプレドープされる。以下、このようなプレドープ方式を「垂直ドープ方式」と称することにする。 In the conventional lithium ion storage (pre-doping) method in the pre-doped storage element, there is a method of pre-doping lithium ions by scraping a part of the negative electrode or pasting lithium metal on the negative electrode. For example, as described in Japanese Patent No. 3485935, a negative electrode formed using a mesh current collector and a positive electrode are alternately stacked with separators interposed therebetween to form an electrode stack, and the stack There is a method of pre-doping lithium ions into the negative electrode through a mesh by disposing a current collector with lithium metal attached to the outside of the body to make electrical contact with the negative electrode. In this method, the lithium metal and the negative electrode face each other, and lithium ions are pre-doped from the direction perpendicular to the negative electrode. Hereinafter, such a pre-doping method is referred to as a “vertical doping method”.
従来のプレドープ方式において、負極の一部を削ったり、負極の上にリチウム金属を貼ったりするプレドープ方式では、リチウム金属を貼った部分に凹凸ができ、その部分に電流が集中してリチウム金属が析出しやすくなる。周知のごとく、析出したリチウム金属がセパレータを破って正極と接触すれば、内部短絡が起こり、発火などの重篤な結果を招く可能性がある。また、垂直ドープ方式は、メッシュなど穴が空いた集電体を用いているため、コストが嵩むという問題を有していた。 In the conventional pre-doping method, in the pre-doping method in which a part of the negative electrode is scraped or lithium metal is pasted on the negative electrode, irregularities are formed on the part on which the lithium metal is pasted, and current concentrates on that part and the lithium metal is Precipitates easily. As is well known, if the deposited lithium metal breaks the separator and comes into contact with the positive electrode, an internal short circuit may occur, resulting in serious consequences such as ignition. In addition, the vertical dope method has a problem that the cost increases because a current collector having a hole such as a mesh is used.
そこで本発明者らは、製造や低価格化が容易なプレドープ方式として、シート状集電体の表面に負極用電極材を塗布して負極を形成するとともに、その集電体面と同じ面にリチウム金属を貼着し、リチウムイオンを集電体の表面に沿って負極にドープする「水平ドープ方式」を採用することとした。また、水平ドープ方式は、垂直ドープ方式と比較して、吸蔵されるリチウムイオンの量を電極各層で精確に設定でき、その後の電池反応を均一にすることができる、という利点があり、信頼性に優れている。このような水平ドープ方式では、負極用電極材を、例えば、ダイコート、グラビアコート、リバースコートなどの塗工技術により、容易かつ安価に集電体の表面に形成することができる。 Therefore, the present inventors applied a negative electrode material on the surface of a sheet-like current collector to form a negative electrode as a pre-doping method that is easy to manufacture and reduce costs, and formed lithium on the same surface as the current collector surface. A “horizontal dope method” was adopted in which metal was attached and lithium ions were doped into the negative electrode along the surface of the current collector. Compared with the vertical doping method, the horizontal doping method has the advantage that the amount of stored lithium ions can be accurately set in each electrode layer, and the subsequent battery reaction can be made uniform, and is reliable. Is excellent. In such a horizontal doping method, the electrode material for the negative electrode can be easily and inexpensively formed on the surface of the current collector by a coating technique such as die coating, gravure coating, and reverse coating.
しかし、水平ドープ方式の非水蓄電素子では、リチウム金属が配置されている負極集電体上の固定位置から遠く離れた位置にある負極にまでリチウムイオンを拡散させているため、非水蓄電素子の組み立てが終わっても、リチウムイオンが負極活物質に対して均一に吸蔵されるまで、その非水蓄電素子を極めて長い時間静置するエージングが必要があった。当然、非水蓄電素子に対する高出力化の要求に対応するために電極面積を大型化すれば、リチウムイオンを吸蔵させるためのエージング期間がさらに長くなる。 However, in the horizontally doped nonaqueous storage element, the lithium ions are diffused to the negative electrode located far from the fixed position on the negative electrode current collector where the lithium metal is disposed. Even after the assembly of (1) was completed, it was necessary to perform aging for allowing the non-aqueous storage element to stand for a very long time until lithium ions were uniformly occluded in the negative electrode active material. Naturally, if the electrode area is increased in order to meet the demand for higher output for the non-aqueous storage element, the aging period for occluding lithium ions is further increased.
長時間に渡るエージングは、生産性を低下させ、製造コストを増大させる。これでは、信頼性を確保できたとしても、水平ドープ方式の非水蓄電素子の製造容易性によるコストダウンの可能性を阻害してしまう。もちろん、コストダウンとともに、リチウム金属の析出を抑えて安全性を確保するとともに、ドープするリチウムイオンの量を精密に制御しなくては実用には耐えられない。しかし、大容量化に加え、急速充放電を可能にしようとすると、極めて大きな電流が蓄電素子内を流れることになり、リチウム金属がさらに析出しやすくなる。すなわち、大容量化や急速充放電性能と、安全性の双方を確保することが難しい。 Aging over a long period of time reduces productivity and increases manufacturing costs. In this case, even if the reliability can be ensured, the possibility of cost reduction due to the ease of manufacturing the horizontally doped non-aqueous storage element is hindered. Of course, it cannot be put into practical use unless the cost is reduced and the deposition of lithium metal is suppressed to ensure safety and the amount of lithium ions to be doped is precisely controlled. However, if an attempt is made to enable rapid charging / discharging in addition to an increase in capacity, an extremely large current flows in the electric storage element, and lithium metal is more likely to precipitate. In other words, it is difficult to ensure both large capacity and rapid charge / discharge performance and safety.
したがって本発明の目的は、水平ドープ方式による非水蓄電素子において、短時間にリチウムイオンのプレドープを完了させてコストダウンを達成するともに、高出力化や急速充放電を可能としつつ、極めて高い安全性を確保することにある。 Accordingly, an object of the present invention is to achieve a cost reduction by completing the pre-doping of lithium ions in a short time in a non-aqueous energy storage device using a horizontal doping method, while achieving high output and rapid charge / discharge, and extremely high safety. It is to ensure sex.
本発明者らは、まず、水平ドープ方式では、リチウムイオンの移動媒体となる電解液中に溶解したリチウム金属が電極面を平行（水平）に拡散しながら負極用電極材中に吸蔵されるという点に着目した。すなわち、水平ドープ方式では、電極面に水平な方向に物質移動経路が形成されていることに着目した。そして、リチウムイオンが吸蔵される負極用電極材は、粉体として用意され、その粉体にバインダーなどを加えてスラリー状にして集電体上に塗布されるため、その粉体の粒径の中央値や粒度分布における各粒径の粉体の割合などには最適条件があるはずである。そして、鋭気研究の結果、その最適条件が存在することを見いだした。もちろん、本発明の目的を達成するためには、最適化された負極用電極材とともに、安全性を備えた基本構造、すなわち、リチウム金属が析出しにくい基本構造を備えた非水蓄電素子とすることが必要である。 First, in the horizontal doping method, the present inventors say that lithium metal dissolved in an electrolytic solution serving as a lithium ion transfer medium is occluded in the negative electrode material while diffusing the electrode surface in parallel (horizontal). Focused on the point. That is, in the horizontal doping method, attention is paid to the fact that the mass transfer path is formed in the direction horizontal to the electrode surface. And the electrode material for negative electrodes in which lithium ions are occluded is prepared as powder, and a binder is added to the powder to form a slurry, which is applied onto the current collector. There should be optimum conditions such as the median and the proportion of powder of each particle size in the particle size distribution. As a result of keen research, we found that the optimum condition exists. Of course, in order to achieve the object of the present invention, a non-aqueous storage element having an optimized negative electrode material and a basic structure with safety, that is, a basic structure in which lithium metal hardly precipitates is obtained. It is necessary.
上記目的を達成するための本発明は、シート状の正極と負極とがセパレータを介して対向配置されてなる１単位の発電要素を１単位以上積層してなる電極積層体をリチウム塩を含む電解液とともに密封封止するとともに、負極側にリチウム金属を起源とするリチウムイオンをあらかじめ吸蔵させてなる非水蓄電素子であって、
前記正極は、一辺に外部端子部が凸設された略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンもしくはアニオンを可逆的に担持可能な正極用電極材が塗布されてなり、
前記負極は、一辺に外部端子部が凸設された前記略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンの吸蔵・放出が可能な負極用電極材が塗布されてなり、
正極側の前記塗布領域は、前記略矩形状のシート状集電体において、少なくとも前記外部端子部を除く領域であり、
負極側の前記塗布領域は、前記略矩形状のシート状集電体の４辺において、前記外部端子部が凸設された辺と当該辺に平行な辺のうち、少なくとも一辺に沿って帯状に設けられた未塗布領域と前記外部端子部の領域以外の領域であり、
前記正極側の塗布領域は、前記発電要素において対向配置される前記負極側の塗布領域より内側であり、
前記リチウムイオンは、前記帯状の未塗布領域に貼着された帯状のリチウム金属を起源として負極用電極材中に拡散することで負極側に吸蔵され、
前記セパレータは、前記発電要素において、少なくとも負極側の塗布領域と未塗布領域とを含めた平面領域に介在し、
前記発電要素において、負極の電位は、前記リチウムイオンが拡散されている状態でリチウム金属に対して２．０Ｖ以下であり、
前記負極用電極材は、粉体から形成され、当該粉体の粒度分布において、粒子径の小さな方から累積して１６％、５０％、８４％のそれぞれの量に対応する粒子径をそれぞれＤ１６と、Ｄ５０、Ｄ８０とした際に、（Ｄ８４−Ｄ１６）／（２×Ｄ５０）≦０．９である
非水蓄電素子としている。
In order to achieve the above object, the present invention provides an electrode laminate in which one unit of power generation elements in which a sheet-like positive electrode and a negative electrode are arranged opposite to each other with a separator interposed therebetween is electrolyzed containing a lithium salt. A non-aqueous energy storage device that is hermetically sealed with a liquid and in which lithium ions originating from lithium metal are occluded in advance on the negative electrode side,
The positive electrode is coated with a positive electrode material capable of reversibly carrying lithium ions or anions in a coating region provided on the surface of a substantially rectangular sheet-like current collector having an external terminal portion protruding on one side. And
In the negative electrode, a negative electrode material capable of occluding and releasing lithium ions is applied to a coating region provided on the surface of the substantially rectangular sheet-like current collector having an external terminal portion protruding on one side. Become
The application area on the positive electrode side is an area excluding at least the external terminal portion in the substantially rectangular sheet-shaped current collector,
The coating area on the negative electrode side is in a strip shape along at least one side of the four sides of the substantially rectangular sheet-shaped current collector among the side where the external terminal portion is projected and the side parallel to the side. It is a region other than the uncoated region provided and the region of the external terminal part,
The application region on the positive electrode side is inside the application region on the negative electrode side that is opposed to the power generation element,
The lithium ions are occluded on the negative electrode side by diffusing into the electrode material for the negative electrode from the band-shaped lithium metal adhered to the band-shaped uncoated region,
In the power generation element, the separator is interposed in a planar region including at least a negative electrode side coating region and an uncoated region,
In the power generation element, the potential of the negative electrode is 2.0 V or less with respect to lithium metal in a state where the lithium ions are diffused.
The negative electrode material is formed from powder, and in the particle size distribution of the powder, the particle diameter corresponding to each of 16%, 50%, and 84% accumulated from the smaller particle diameter is D16. And when it is set as D50 and D80, it is set as the nonaqueous electrical storage element which is (D84-D16) / (2 * D50) <= 0.9.
また、上記非水蓄電素子において、前記発電要素の正極および負極は、それぞれの外部端子部が反対方向に凸設するように対向配置され、
前記略矩形状のシート状集電体において、前記外部端子部が形成される側の辺およびこれに平行する辺は、当該辺に直交する辺より長く、
前記凸状の外部端子部は、シート状集電体に１つ以上凸設され、自身が形成される側の辺の長さＨと、当該辺に平行な自身における辺の長さの合計Ｌとが、３Ｌ≧Ｈであることとしてもよい。
Further, in the non-aqueous energy storage device, the positive electrode and the negative electrode of the power generation element are arranged to face each other so that each external terminal portion protrudes in the opposite direction,
In the substantially rectangular sheet-shaped current collector, the side on which the external terminal portion is formed and the side parallel to the side are longer than the side orthogonal to the side,
One or more of the convex external terminal portions are provided so as to protrude from the sheet-like current collector, and the total length L of the side on the side where the convex external terminal is formed and the side length of the side parallel to the side. Or 3L ≧ H.
あるいは、シート状の正極と負極とがセパレータを介して対向配置してなる発電要素を１単位として、少なくとも１単位以上の発電要素を積層してなる電極積層体をリチウム塩を含む電解液とともに密封封止するとともに、負極にリチウム金属を起源とするリチウムイオンをあらかじめ拡散してなる非水蓄電素子であって、
正極は、一辺に外部端子部が凸設された略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンもしくはアニオンを可逆的に担持可能な正極用電極材が塗布されてなり、
負極は、一辺に外部端子部が凸設された前記略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンの吸蔵・放出が可能な負極用電極材が塗布されてなり、
正極側の前記塗布領域は、前記略矩形状のシート状集電体において、少なくとも前記外部端子部を除く領域であり、
前記略矩形状のシート状集電体の４辺において、前記外部端子部が凸設された辺と直交する２辺のそれぞれに沿う２つの帯状の領域とこれら２辺に平行でシート状集電体を横断する帯状の領域のうち、少なくとも一つの領域を未塗布領域として、負極側の前記塗布領域は、当該未塗布領域と前記外部端子部の領域以外の領域であり、
前記正極側の塗布領域は、前記発電要素において対向配置される前記負極側の塗布領域より内側であり、
前記リチウムイオンは、前記帯状の未塗布領域に貼着された帯状のリチウム金属を起源として負極用電極材中に拡散することで負極側に吸蔵され、
前記セパレータは、前記発電要素において、少なくとも負極側の塗布領域と未塗布領域とを含めた平面領域に介在し、
前記発電要素において、負極の電位は、前記リチウムイオンが拡散されている状態でリチウム金属に対して２．０Ｖ以下であり、
前記負極用電極材は、粉体から形成され、当該粉体の粒度分布において、粒子径の小さな方から累積して１６％、５０％、８４％のそれぞれの量に対応する粒子径をそれぞれＤ１６と、Ｄ５０、Ｄ８０とした際に、（Ｄ８４−Ｄ１６）／（２×Ｄ５０）≦０．９である
非水蓄電素子とすることもできる。
Alternatively, a power generation element in which a sheet-like positive electrode and a negative electrode are arranged to face each other with a separator as a unit, and an electrode laminate formed by laminating at least one unit of power generation elements is sealed together with an electrolyte containing a lithium salt A non-aqueous energy storage device in which lithium ions originating from lithium metal are previously diffused into the negative electrode while sealing,
In the positive electrode, a positive electrode material capable of reversibly carrying lithium ions or anions is applied to a coating region provided on the surface of a substantially rectangular sheet-like current collector having an external terminal portion protruding on one side. Become
The negative electrode is formed by applying a negative electrode material capable of occluding and releasing lithium ions to a coating region provided on the surface of the substantially rectangular sheet-shaped current collector having an external terminal portion protruding on one side. ,
The application area on the positive electrode side is an area excluding at least the external terminal portion in the substantially rectangular sheet-shaped current collector,
On the four sides of the substantially rectangular sheet-shaped current collector, two strip-shaped regions along each of two sides orthogonal to the side on which the external terminal portion is projected, and a sheet-shaped current collector parallel to these two sides. Of the strip-shaped region crossing the body, at least one region is an uncoated region, and the coated region on the negative electrode side is a region other than the uncoated region and the region of the external terminal portion,
The application region on the positive electrode side is on the inner side of the application region on the negative electrode side opposed to the power generation element,
The lithium ions are occluded on the negative electrode side by diffusing into the electrode material for the negative electrode starting from the band-shaped lithium metal attached to the band-shaped uncoated region,
In the power generation element, the separator is interposed in a planar region including at least a negative electrode side coating region and an uncoated region,
In the power generation element, the potential of the negative electrode is 2.0 V or less with respect to lithium metal in a state where the lithium ions are diffused,
The negative electrode material is formed from powder, and in the particle size distribution of the powder, the particle diameter corresponding to each of 16%, 50%, and 84% accumulated from the smaller particle diameter is D16. And when it is set as D50 and D80, it can also be set as the non-aqueous electrical storage element which is (D84-D16) / (2xD50) <= 0.9.
上記各非水蓄電素子において、Ｄ５０≦０．８μｍとすれば好ましい。さらに好ましくは、負極用電極材の形成起源となる前記粉体の形状を球状とすることである。 In each of the above non-aqueous storage elements, it is preferable that D50 ≦ 0.8 μm. More preferably, the shape of the powder, which is the origin of formation of the electrode material for the negative electrode, is spherical.
なお、本発明者らは、以前、水平ドープ方式におけるリチウムイオンの移動距離につて検討し、その移動距離にも適正値があることを知見し、その知見に基づく発明を先に出願した（特願２００７−２９３２６５）。本発明は、上記非水蓄電素子にこの知見に基づく構成を加えた非水蓄電素子にも及んでおり、当該発明は、上記各非水蓄電素子において、シート状集電体における負極用電極材の塗布領域と前記リチウム金属との距離が９０ｍｍ以下である非水蓄電素子としている。 In addition, the present inventors previously examined the movement distance of lithium ions in the horizontal doping method, found that the movement distance has an appropriate value, and filed an invention based on that knowledge first (special feature). Application 2007-293265). The present invention also extends to a non-aqueous storage element obtained by adding a configuration based on this knowledge to the non-aqueous storage element, and the present invention relates to the above-described non-aqueous storage element, and the electrode material for a negative electrode in a sheet-like current collector The non-aqueous energy storage device is such that the distance between the coating region and the lithium metal is 90 mm or less.
本発明の非水蓄電素子によれば、十分な安全性や蓄電性能を備えるとともに、低いコストでの製造が可能で、低価格化が期待できる。 According to the nonaqueous electricity storage device of the present invention, sufficient safety and electricity storage performance are provided, and manufacturing at a low cost is possible, and a reduction in price can be expected.
本発明に係る非水蓄電素子は、上記水平ドープ方式の非水蓄電素子であり、負極用電極材の粒度分布に基づいて算出される所定のパラメータについて最適条件を設定している点に最も大きな特徴がある。そして、本発明では、その最適条件を備えた負極用電極材を負極に適用してシート状の集電体上に塗布する際の領域や形状に応じて、概ね、２つの実施形態がある。以下では、まず、当該２つの実施形態のそれぞれについて、代表的な形態を第１および第２の実施例として挙げて本発明の非水蓄電素子の構造について説明し、その上で、上記粒度分布に基づくパラメータについて説明する。 The non-aqueous storage element according to the present invention is the above-mentioned horizontal dope non-aqueous storage element, and is the largest in that an optimum condition is set for a predetermined parameter calculated based on the particle size distribution of the electrode material for the negative electrode. There are features. In the present invention, there are generally two embodiments according to the region and shape when the negative electrode material having the optimum condition is applied to the negative electrode and applied onto the sheet-like current collector. In the following, first, for each of the two embodiments, typical structures will be described as first and second examples to describe the structure of the non-aqueous storage element of the present invention, and then the particle size distribution will be described. The parameters based on will be described.
＝＝＝第１の実施例＝＝＝
本発明の第１の実施例における非水蓄電素子（以下、蓄電素子）について、図１の（Ａ）と（Ｂ）に、それぞれ正極の概略構造と負極の概略構造とを示した。また、（Ｃ）（Ｄ）に負極の一部拡大図を示した。当該構造において、正極１０ａｐと負極１０ａｎは、それぞれ、略矩形のシート状集電体（以下、集電体シート、１１ｐ、１１ｎ）の表面にそれぞれの電極材（１２ｐ，１２ｎ）が塗布された構造となっている。
=== First Embodiment ===
About the non-aqueous electricity storage element (henceforth an electricity storage element) in the 1st Example of this invention, the schematic structure of the positive electrode and the schematic structure of the negative electrode were respectively shown to (A) and (B) of FIG. In addition, (C) and (D) are partially enlarged views of the negative electrode. In this structure, each of the positive electrode 10ap and the negative electrode 10an has a structure in which each electrode material (12p, 12n) is applied to the surface of a substantially rectangular sheet-like current collector (hereinafter, current collector sheets, 11p, 11n). It has become.
略矩形の集電体シート（１１ｐ、１１ｎ）の一辺には凸形状となる領域（１３ｐ，１３ｎ）が形成されており、この領域（１３ｐ，１３ｎ）は、正極１０ａｐと負極１０ａｎをセパレータを介して対向配置させた状態で積層して蓄電素子を構成した際、蓄電素子を充電したり、当該デバイスに蓄えられた電気を取り出したりするための端子となる部分（外部端子部：１３ｐ、１３ｎ）となる。そして、正極用電極材１２ｐと負極用電極材１２ｎは、それぞれ、外部端子部（１３ｐ、１３ｎ）を余白として、集電体シート（１１ｐ、１１ｎ）上に形成された塗布領域（１４ｐ，１４ｎ）に塗布される。以下では、矩形状集電体シート（１１ｐ，１１ｎ）において、外部端子部（１３ｐ、１３ｎ）が凸設される側の辺１５の延長方向を上下方向とし、その延長方向に直交する方向を左右方向として説明する。 Convex regions (13p, 13n) are formed on one side of the substantially rectangular current collector sheet (11p, 11n). The regions (13p, 13n) are connected to the positive electrode 10ap and the negative electrode 10an via a separator. When the power storage element is configured by stacking in a state of being opposed to each other, a portion to be a terminal for charging the power storage element or taking out the electricity stored in the device (external terminal portions: 13p, 13n) It becomes. The positive electrode material 12p and the negative electrode material 12n are applied regions (14p, 14n) formed on the current collector sheets (11p, 11n) with the external terminal portions (13p, 13n) as blanks, respectively. To be applied. In the following, in the rectangular current collector sheet (11p, 11n), the extending direction of the side 15 on the side where the external terminal portions (13p, 13n) are protruded is defined as the vertical direction, and the direction orthogonal to the extending direction is defined as the left-right direction. This will be described as a direction.
正極１０ａｐにおける正極用電極材１２ｐの塗布領域１４ｐは、外部端子部１３ｐ以外のほぼ全面となる略矩形となっている（Ａ）。一方、負極１０ａｎは、集電体シート１１ｎにおいて、外部端子部１３ｎに加え、外部端子部１３ｎが形成されている辺１５ｎ、およびそれに平行する他端側の辺１６ｎ、すなわち上下方向に延長する左右両側の２辺（１５ｎ，１６ｎ）に沿って余白１７ｎが形成されるように塗布されている（Ｂ）。当該両辺（１５ｎ，１６ｎ）に沿ったそれぞれの余白部分１７ｎには上下方向に延長する帯状のリチウム金属２０が貼着されている。もちろん、上下方向の一方の辺（１５ｎ，１６ｎ）の何れかにのみ、リチウム金属２０を貼着するための余白１７ｎが形成されていてもよい。 The application region 14p of the positive electrode material 12p in the positive electrode 10ap has a substantially rectangular shape that is substantially the entire surface other than the external terminal portion 13p (A). On the other hand, the negative electrode 10an includes, in the current collector sheet 11n, in addition to the external terminal portion 13n, the side 15n where the external terminal portion 13n is formed, and the side 16n on the other end side parallel to the side 15n, It is applied so that a margin 17n is formed along two sides (15n, 16n) on both sides (B). A strip-shaped lithium metal 20 extending in the vertical direction is attached to each blank portion 17n along the both sides (15n, 16n). Of course, a margin 17n for attaching the lithium metal 20 may be formed only on one of the sides (15n, 16n) in the vertical direction.
なお、この第１の実施例では、正極１０ａｐと負極１０ａｎは、上下方向については、ともに集電体シート（１１ｐ，１１ｎ）の両端の辺（１８ｐ，１８ｎ）まで電極材（１２ｐ，１２ｎ）が塗布されている。このような形状の領域（塗布領域：１４ｐ，１４ｎ）に電極材（１２ｐ，１２ｎ）を塗布する方法としては、スラリー状の電極材（スラリー）を周知のドクターブレードを用いて塗布することが考えられる。そして、第１の実施例では、集電シート（１１ｐ，１１ｎ）の上端と下端の辺（１８ｐ，１８ｎ）に沿って余白がなく、その余白を設けるために特別な工程が不要となる。そのため、塗布領域（１４ｐ，１４ｎ）の左右幅でスラリーを供給すればよく、第１の実施例における電極構造を採用した蓄電素子では、生産性の向上と、それに伴うコストダウンが期待できる。 In the first embodiment, the positive electrode 10ap and the negative electrode 10an have the electrode material (12p, 12n) up to the sides (18p, 18n) at both ends of the current collector sheet (11p, 11n) in the vertical direction. It has been applied. As a method of applying the electrode material (12p, 12n) to the region having such a shape (application region: 14p, 14n), it is considered that the slurry-like electrode material (slurry) is applied using a known doctor blade. It is done. In the first embodiment, there is no margin along the upper and lower sides (18p, 18n) of the current collector sheets (11p, 11n), and no special process is required to provide the margin. Therefore, it is sufficient to supply the slurry with the left and right widths of the coating regions (14p, 14n), and in the electricity storage device employing the electrode structure in the first embodiment, improvement in productivity and associated cost reduction can be expected.
＝＝＝リチウム金属の析出防止構造＝＝＝
蓄電素子は、上述した正極１０ａｎと負極１０ａｐをセパレータを介して対向配置して１単位の発電要素とし、その発電要素を１層以上積層して電極積層体（以下、積層体）を構成した後、外部端子部（１３ｐ，１３ｎ）にリード板を溶接などによって接続する。そして、積層体をラミネートフィルムの中に電解液とともに封入し、エージングのために所定期間保存し、使用可能な状態として完成する。
=== Precipitation prevention structure of lithium metal ===
In the electricity storage element, the positive electrode 10an and the negative electrode 10ap described above are arranged to face each other via a separator to form one unit of power generation element, and one or more layers of the power generation elements are stacked to form an electrode stack (hereinafter referred to as a stack). The lead plate is connected to the external terminal portions (13p, 13n) by welding or the like. And a laminated body is enclosed with an electrolyte solution in a laminate film, preserve | saved for a predetermined period for aging, and is completed as a usable state.
図２（Ａ）（Ｂ）に、蓄電素子の基本構造となる１層からなる積層体の構造を示した。また、図２（Ｃ）に蓄電素子における電流分布状態を模式的に示した。ここでは、上記第１の実施例における正極１０ａｐと負極１０ａｎからなる積層体３０ａの構造を示した。当該積層体３０ａは、上述したように集電体シート（１１ｐ，１１ｎ）上に電極材（１２ｐ，１２ｎ）を塗布してなる正極１０ａｐと負極１０ａｎをセパレータ４０を介して対向配置した積層構造であり、また、正負両極（１０ａｐ，１０ａｎ）における外部端子部（１３ｐ，１３ｎ）が、それぞれ反対方向に突出するように積層されている。 FIGS. 2A and 2B show the structure of a single-layer structure that is the basic structure of the power storage element. FIG. 2C schematically shows the current distribution state in the power storage element. Here, the structure of the laminated body 30a composed of the positive electrode 10ap and the negative electrode 10an in the first embodiment is shown. The laminated body 30a has a laminated structure in which the positive electrode 10ap and the negative electrode 10an formed by applying the electrode material (12p, 12n) on the current collector sheets (11p, 11n) are arranged to face each other via the separator 40 as described above. In addition, the external terminal portions (13p, 13n) in the positive and negative electrodes (10ap, 10an) are laminated so as to protrude in opposite directions.
（Ａ）は、当該積層体３０ａを上面から見たときに、積層状態にある正負両極（１０ｐ，１０ｎ）における塗布領域（１４ｐ，１４ｎ）を比較するための図である。（Ｂ）は、当該積層体３０ａの断面図である。 (A) is a figure for comparing the application | coating area | region (14p, 14n) in the positive / negative both poles (10p, 10n) in a lamination | stacking state, when the said laminated body 30a is seen from an upper surface. (B) is sectional drawing of the said laminated body 30a.
正負両極（１０ａｐ，１０ａｎ）において、それぞれの電極材（１２ｐ，１２ｎ）が塗布される領域（１４ｐ，１４ｎ）は、Ｘｐ＜Ｘｎ、Ｙｐ＜Ｙｎとなっており、正極１０ａｐにおける塗布領域１４ｐが負極１０ａｎにおける塗布領域１４ｎの内側に収まるようになっている。すなわち、積層体３０ａにおいて、正負極間に流れる電流５０は、各電極塗布領域（１４ｐ，１４ｎ）のエッジ部分（５１ｐ，５１ｎ）に集中する（Ｃ）。負極１０ａｎにおけるエッジ部分５１ｎに電流５０が集中するとリチウム金属が析出しやすくなるため、本発明では、負極塗布領域１４ｎの内側に正極塗布領域１４ｐが全て収まるようにして、負極１０ａｎ側のエッジ５１ｎに電流を集中させないようにしている。それによって、正負両極間に流れる電流５０によってリチウム金属が析出する可能性を低くしている。また、例え、負極１０ａｎのエッジ５１ｎにリチウム金属が析出したとしても、そのエッジ５１ｎの対向面には正極用電極材１２ｐが無いので、両極の電極材（１２ｐ，１２ｎ）同士が短絡することがない。 In the positive and negative electrodes (10ap, 10an), the regions (14p, 14n) to which the respective electrode materials (12p, 12n) are applied are Xp <Xn, Yp <Yn, and the coating region 14p in the positive electrode 10ap is the negative electrode. It fits inside the coating area 14n at 10an. That is, in the laminate 30a, the current 50 flowing between the positive and negative electrodes is concentrated on the edge portions (51p, 51n) of the respective electrode application regions (14p, 14n) (C). When the current 50 concentrates on the edge portion 51n of the negative electrode 10an, lithium metal is likely to be deposited. Therefore, in the present invention, the positive electrode application region 14p is entirely contained inside the negative electrode application region 14n, and the negative electrode 10an side edge 51n is disposed. The current is not concentrated. Thereby, the possibility of precipitation of lithium metal by the current 50 flowing between the positive and negative electrodes is reduced. For example, even if lithium metal is deposited on the edge 51n of the negative electrode 10an, there is no positive electrode material 12p on the opposite surface of the edge 51n. Absent.
また、リチウム金属の析出は、正負極間の電流５０だけでなく、負極表面に流れる電流によっても発生する可能性がある。第１の実施例では、負極１０ａｎにおけるリチウム金属２０を貼着するための帯状の余白領域（以下、未塗布領域）１７ｎの延長方向と外部端子部１３ｎとの位置関係が、集電体シート１１表面に流れる電流によるリチウム金属の析出を防止するための重要な要件となっている。図３に当該位置関係についての説明図を示した。この図では、リチウム金属が析出し易い構造の負極１０ｎを例示し、その負極１０ｎの平面図と断面図を（Ａ）と（Ｂ）にそれぞれ示した。例えば、リチウム金属２０を貼着するための未塗布領域１７ｎを集電体シート１１ｎの中央に上下方向に縦断するように設け、その未塗布領域１７ｎの左右に負極用電極材１２ｎの塗布領域１４ｎを形成すると（Ａ）、この未塗布領域１７ｎとその左右に塗布される負極用電極材１２ｎの表面との間に段差１９が生じる（Ｂ）。そして、外部端子部１３ｎを電流５２の入出力部として集電体シート１１ｎ上に電流５２が流れると、その流路途上に上記段差１９があり、その段差１９によるエッジ５３に電流５２が集中し、リチウム金属が析出する可能性が高くなる。したがって、第１の実施例では、リチウム金属２０を貼着するための未塗布領域１７ｎは、略矩形の集電体シート１１ｎにおいて、外部端子部１３ｎが形成されている辺１５ｎとそれに平行な辺１６ｎの何れか、あるいは両方に形成されることになる。 In addition, the deposition of lithium metal may occur not only by the current 50 between the positive and negative electrodes, but also by the current flowing on the negative electrode surface. In the first example, the positional relationship between the extending direction of the band-shaped blank region (hereinafter referred to as an uncoated region) 17n for adhering the lithium metal 20 in the negative electrode 10an and the external terminal portion 13n is the current collector sheet 11. This is an important requirement for preventing the deposition of lithium metal due to the current flowing on the surface. FIG. 3 shows an explanatory diagram of the positional relationship. In this figure, a negative electrode 10n having a structure in which lithium metal is likely to be deposited is illustrated, and a plan view and a cross-sectional view of the negative electrode 10n are shown in (A) and (B), respectively. For example, an uncoated region 17n for attaching the lithium metal 20 is provided in the center of the current collector sheet 11n so as to be vertically cut, and the coated region 14n of the negative electrode material 12n is formed on the left and right of the uncoated region 17n. When (A) is formed, a step 19 is formed between the uncoated region 17n and the surface of the negative electrode material 12n applied to the left and right (B). When the current 52 flows on the current collector sheet 11n using the external terminal portion 13n as the input / output portion of the current 52, the step 19 is in the flow path, and the current 52 is concentrated on the edge 53 due to the step 19. The possibility that lithium metal will precipitate increases. Therefore, in the first embodiment, the uncoated region 17n for adhering the lithium metal 20 is the side 15n where the external terminal portion 13n is formed in the substantially rectangular current collector sheet 11n and the side parallel to the side 15n. It is formed in either or both of 16n.
なお、リチウム金属２０と負極用電極材１２ｎの塗布領域１４ｎは、先の出願（特願２００７−２９３２６５）にもあるように、９０ｍｍ以下とすることが望ましい。すなわち、図１（Ｃ）（Ｄ）に示した塗布領域側１７ｎの辺２１と、図１（Ａ）に示した塗布領域１４ｎを左右に２分する線２２までの距離Ｌを９０ｍｍ以下とするとリチウムイオンが均一かつ迅速に拡散する。 The application region 14n of the lithium metal 20 and the negative electrode material 12n is desirably 90 mm or less as described in the previous application (Japanese Patent Application No. 2007-293265). That is, when the distance L between the side 21 on the application region side 17n shown in FIGS. 1C and 1D and the line 22 that bisects the application region 14n shown in FIG. Lithium ions diffuse uniformly and rapidly.
ところで、蓄電素子は、上述した一組の正極１０ａｐと負極１０ａｎとからなる１層分の積層体３０ａをさらに多数積層して多層構造の積層体にするのが普通である。図４（Ａ）（Ｂ）に、多層構造の積層体を備えた蓄電素子の概略図を示した。（Ａ）は多層構造の積層体６０ａの断面図であり、図２に示した一層からなる積層体３０ａについて、同じ極同士の外部端子部（１３ｐ，１３ｎ）が同じ方向に凸設されるように多数積層することで構成されている。（Ｂ）は、多層構造の積層体６０ａを備えた蓄電素子１ａにおいて、各層３０ａからの外部端子部（１３ｐ，１３ｎ）についての末端構造を示す拡大図である。同じ極同士の外部端子部（１３ｐ，１３ｎ）が積層された状態で、一括してリード板７０に溶接されている。それによって、各層毎に形成される１層からなる蓄電素子が並列接続される。そして、そのリード板７０の先端側をラミネートフィルムの外装体８０の外に露出させた状態で、積層体６０ａを電解液とともにラミネートフィルム内に密封して構造体としての蓄電素子を完成させる。 By the way, the power storage element is usually formed by stacking a large number of one-layer laminated bodies 30a composed of the above-described pair of positive electrode 10ap and negative electrode 10an into a multilayer structure. 4A and 4B are schematic views of a power storage element including a multilayer structure. (A) is sectional drawing of the laminated body 60a of a multilayer structure, and the external terminal part (13p, 13n) of the same pole protrudes in the same direction about the laminated body 30a which consists of one layer shown in FIG. It is comprised by laminating | stacking many. (B) is an enlarged view showing a terminal structure of external terminal portions (13p, 13n) from each layer 30a in the electricity storage device 1a including the multilayer body 60a. The external terminal portions (13p, 13n) of the same poles are laminated and welded together to the lead plate 70. Thereby, the electricity storage elements composed of one layer formed for each layer are connected in parallel. Then, with the leading end side of the lead plate 70 exposed to the outside of the laminate film outer package 80, the laminate 60a is sealed in the laminate film together with the electrolytic solution to complete a power storage element as a structure.
＝＝＝第２の実施例＝＝＝＝
本発明の第２の実施例における非水蓄電素子（以下、蓄電素子）について、図５（Ａ）と（Ｂ）に、それぞれ正極の概略構造と負極の概略構造を示した。正極１０ｂｐと負極１０ｂｎは、第１の実施例と同様に、略矩形の一辺に外部端子部（１３ｐ，１３ｎ）が凸設された集電体シート（１１ｐ，１１ｎ）上にそれぞれの電極材（１２ｐ，１２ｎ）が塗布されることで形成されている。しかし、第１の実施例とこの第２の実施例とは、リチウム金属２０が貼着される帯状の未塗布領域１７ｎの延長方向が異なる。第２の実施例では、負極１０ｂｎの集電体シート１１ｎにおいて、外部端子部１３ｎが形成されている辺に直交する方向に未塗布領域１７ｎが延長している。
=== Second Embodiment ====
About the nonaqueous electrical storage element (henceforth electrical storage element) in the 2nd Example of this invention, the schematic structure of the positive electrode and the schematic structure of the negative electrode were respectively shown to FIG. 5 (A) and (B). Similarly to the first embodiment, the positive electrode 10bp and the negative electrode 10bn are formed on the current collector sheet (11p, 11n) having external terminal portions (13p, 13n) projecting on one side of a substantially rectangular shape. 12p, 12n) is applied. However, the extending direction of the strip-shaped uncoated region 17n to which the lithium metal 20 is attached is different between the first embodiment and the second embodiment. In the second embodiment, in the current collector sheet 11n of the negative electrode 10bn, the uncoated region 17n extends in a direction orthogonal to the side where the external terminal portion 13n is formed.
なお、第２の実施例では、電流５２の方向と未塗布領域の延長方向とが一致しているため、未塗布領域１７ｎは、集電体シート１１ｎにおける左右に延長する辺１８ｎに沿って形成してもよいし、集電体シート１１ｎの内側を左右方向に横断するように形成してもよい。図６（Ａ）と（Ｂ）に未塗布領域（１７ｐ，１７ｎ）が集電体シート（１１ｐ，１１ｎ）の内側を横断するように形成された正極１０ｃｐと負極１０ｃｎの平面図を示した。負極１０ｃｎ側の未塗布領域１７ｎに対応して、正極１０ｃｐ側にも集電体シート１１ｐを横断するように帯状の未塗布領域１７ｐが設けられている。 In the second embodiment, since the direction of the current 52 and the extension direction of the non-application area coincide with each other, the non-application area 17n is formed along the side 18n extending to the left and right in the current collector sheet 11n. Alternatively, it may be formed so as to cross the inside of the current collector sheet 11n in the left-right direction. FIGS. 6A and 6B are plan views of the positive electrode 10cp and the negative electrode 10cn formed so that the uncoated regions (17p, 17n) cross the inside of the current collector sheets (11p, 11n). Corresponding to the uncoated region 17n on the negative electrode 10cn side, a strip-shaped uncoated region 17p is also provided on the positive electrode 10cp side so as to cross the current collector sheet 11p.
図７（Ａ）と（Ｂ）に、それぞれ図５と図６に示した正極（１０ｂｐ，１０ｃｐ）と負極（１０ｂｎ，１０ｃｎ）からなる１単位の積層体（３０ｂ，３０ｃ）の平面図を、各極の塗布領域（１４ｐ，１４ｎ）がわかるように示した。この第２の実施例においても、第１の実施例と同様に、負極用電極材１２ｎの塗布領域１４ｎを縁取るエッジ部分に電流が集中しないように、正極用電極材１２ｐの塗布領域１４ｐは、対向配置される負極用電極材１２ｎの塗布領域１４ｎの内側となっている。また、図５、図７（Ａ）に示した構造では、正極１０ｂｐは、外部端子部１３ｐを除いた領域全面を塗布領域１４ｐとしているため、負極１０ｂｎの未塗布領域１７ｎに対向する部分には集電体自体が存在しない。したがって、この対向部分にはキャパシタとしての機能がなく、特性が安定することが期待できる。また、エージング後にリチウム金属２０が残った場合、そのリチウム金属２０が正極１０ｂｐ側の集電体シート１１ｐの表面に接触する可能性も無くなる。図６、図７（Ｂ）に示した電極構造であっても、正極１０ｃｐ側における未塗布領域１７ｐの金属箔を打ち抜くなどして、負極１０ｃｎ側の未塗布領域１７ｎに対向する集電体自体を無くすことができる。 7A and 7B are plan views of a single unit laminate (30b, 30c) composed of the positive electrode (10bp, 10cp) and the negative electrode (10bn, 10cn) shown in FIGS. 5 and 6, respectively. It shows so that the application | coating area | region (14p, 14n) of each pole may be understood. Also in the second embodiment, similarly to the first embodiment, the application region 14p of the positive electrode material 12p is not concentrated on the edge portion bordering the application region 14n of the negative electrode material 12n. The inner side of the coating region 14n of the electrode material 12n for the negative electrode disposed oppositely. Further, in the structure shown in FIGS. 5 and 7A, the positive electrode 10bp has the entire region excluding the external terminal portion 13p as the application region 14p, so that the portion facing the non-application region 17n of the negative electrode 10bn There is no current collector itself. Therefore, this opposing portion does not have a function as a capacitor, and it can be expected that the characteristics are stabilized. In addition, when the lithium metal 20 remains after aging, there is no possibility that the lithium metal 20 contacts the surface of the current collector sheet 11p on the positive electrode 10bp side. Even in the electrode structure shown in FIGS. 6 and 7B, the current collector itself facing the uncoated region 17n on the negative electrode 10cn side by punching the metal foil of the uncoated region 17p on the positive electrode 10cp side or the like. Can be eliminated.
なお、この第２の実施例では、上述したように、負極（１０ｂｎ，１０ｃｎ）における帯状の未塗布領域１７ｎの延長方向と電流５２の方向とが一致する。すなわち、電流５２の流路途上にエッジがない。そのため、リチウム金属２０と負極用電極材１２ｎの塗布領域１４ｎとの距離を（例えば、９０ｍｍに）制限したとしても、正極（１０ｂｐ，１０ｃｐ）も含めて、集電体シート（１１ｐ，１１ｎ）の左右方向のサイズに制限がなく、電極面積を拡大することができ、容易に大容量化を達成することができる。その一方で、この第２の実施例では、第１の実施例のように、ドクターブレードのスラリー供給幅を設定するだけで未塗布領域（１７ｐ，１７ｎ）を形成することができない。しかし、スクリーン印刷など従来の塗布技術を適用することができ、第１の実施例より製造コストが若干高くても、垂直ドープ方式と比較すれば極めて低いコストで製造することができる。 In the second embodiment, as described above, the extending direction of the strip-shaped uncoated region 17n in the negative electrode (10bn, 10cn) coincides with the direction of the current 52. That is, there is no edge in the flow path of the current 52. Therefore, even if the distance between the application region 14n of the lithium metal 20 and the negative electrode material 12n is limited (for example, to 90 mm), the current collector sheet (11p, 11n) including the positive electrode (10bp, 10cp) is also included. There is no limitation on the size in the left-right direction, the electrode area can be enlarged, and a large capacity can be easily achieved. On the other hand, in the second embodiment, as in the first embodiment, the uncoated areas (17p, 17n) cannot be formed only by setting the slurry supply width of the doctor blade. However, a conventional coating technique such as screen printing can be applied, and even if the manufacturing cost is slightly higher than that of the first embodiment, it can be manufactured at an extremely low cost as compared with the vertical doping method.
＝＝＝積層体における外部端子部の位置について＝＝＝
積層体における正極と負極のそれぞれの外部端子部は、反対方向に凸設させるように積層せず、同方向に凸設させるように積層することもできる。外部端子部を同方向に凸設させた蓄電素子について、図８（Ａ）と（Ｂ）にそれぞれ正極と負極の平面図を示した。この図では、第１の実施例の変更形態として例示している。外部端子部（１３ｐ，１３ｎ）は、上下方向の１辺（１５ｐ，１５ｎ）の上方あるいは下方の一方に凸設されている。正極１０ｄｐは、第１の実施例と同様に、この外部電極部１３ｐを除くほぼ全面に正極用電極材１２ｐが塗布されている。負極１０ｄｎは、外部電極部１３ｎとリチウム金属２０を貼着するための未塗布領域１７ｎとを残して負極用電極材１２ｎが塗布されている。なお、この例では、負極１０ｄｎにおける未塗布領域１７ｎは、上下方向に延長する２辺（１５ｎ，１６ｎ）のうち、外部電極部１３ｎがない辺１６ｎにのみ設けられている。また、上下方向の辺（１５ｐ，１５ｎ，１６ｐ，１６ｎ）に対して左右方向（１９ｐ，１９ｎ）の辺が短く、外部端子部（１３ｐ，１３ｎ）を除いた集電体シート（１１ｐ，１１ｎ）の形状は、上下に長い長方形となっている。
=== Regarding the Position of the External Terminal Part in the Laminate ===
The external terminal portions of the positive electrode and the negative electrode in the laminate can be laminated so as to protrude in the same direction without being stacked so as to protrude in the opposite direction. 8A and 8B are plan views of the positive electrode and the negative electrode, respectively, for the power storage element in which the external terminal portion is protruded in the same direction. In this figure, it is illustrated as a modified form of the first embodiment. The external terminal portions (13p, 13n) are provided so as to protrude above or below one side (15p, 15n) in the vertical direction. As in the first embodiment, the positive electrode 10dp is coated with the positive electrode material 12p on almost the entire surface excluding the external electrode portion 13p. The negative electrode 10dn is coated with the negative electrode material 12n, leaving the external electrode portion 13n and the uncoated region 17n for adhering the lithium metal 20. In this example, the uncoated region 17n in the negative electrode 10dn is provided only on the side 16n where the external electrode portion 13n is not provided, of the two sides (15n, 16n) extending in the vertical direction. Further, the current collector sheet (11p, 11n) excluding the external terminal portions (13p, 13n) is shorter in the left-right direction (19p, 19n) than the vertical sides (15p, 15n, 16p, 16n). The shape of is a rectangle that is long in the vertical direction.
図９の（Ａ）と（Ｂ）に図８に示した正極１０ｄｐと負極１０ｄｎとを対向配置させた１単位の積層体３０ｄの平面図と断面図を示した。当該積層体３０ｄは、第１の実施例と同様に、正極１０ｄｐにおける塗布領域１４ｐが、負極１０ｄｎにおける塗布領域１４ｎの内側にある（Ｘｎ＞Ｘｐ，Ｙｎ＞Ｙｐ）。しかしこの例では、外部電極部（１３ｐ，１３ｎ）が同じ方向となるように積層されている。また、正極１０ｄｐと負極１０ｄｎのそれぞれの側の外部電極部（１３ｐ，１３ｎ）は積層方向において重ならないようになっており、正負両極（１０ｄｐ，１０ｄｎ）の外部電極部（１３ｐ，１３ｎ）同士が接触しにくい構造となっている。さらに、負極１０ｄｎには、外部端子部１３ｎが形成されている辺１５ｎに沿ってリチウム金属２０を貼着するための未塗布領域１７ｎがなく、リチウム金属２０は、外部電極部１３ｎがない側の辺１６ｎに沿う帯状の未塗布領域１７ｎにのみ貼着されている。したがって、リチウム金属２０の対向面には、正極１０ｄｐ側の集電体シート１１ｐもないことになり、エージング後にリチウム金属２０が残った場合でも、そのリチウム金属２０による短絡を完全に防止することができる。 9A and 9B are a plan view and a cross-sectional view of one unit of the stacked body 30d in which the positive electrode 10dp and the negative electrode 10dn illustrated in FIG. 8 are arranged to face each other. In the stacked body 30d, as in the first embodiment, the coating region 14p in the positive electrode 10dp is inside the coating region 14n in the negative electrode 10dn (Xn> Xp, Yn> Yp). However, in this example, the external electrode portions (13p, 13n) are stacked so as to be in the same direction. Further, the external electrode portions (13p, 13n) on the respective sides of the positive electrode 10dp and the negative electrode 10dn do not overlap in the stacking direction, and the external electrode portions (13p, 13n) of the positive and negative electrodes (10dp, 10dn) are connected to each other. It has a structure that is difficult to contact. Further, the negative electrode 10dn has no uncoated region 17n for adhering the lithium metal 20 along the side 15n where the external terminal portion 13n is formed, and the lithium metal 20 is on the side where the external electrode portion 13n is not provided. It is attached only to the strip-shaped uncoated region 17n along the side 16n. Therefore, there is no current collector sheet 11p on the positive electrode 10dp side on the opposite surface of the lithium metal 20, and even when the lithium metal 20 remains after aging, it is possible to completely prevent a short circuit due to the lithium metal 20. it can.
＝＝＝セパレータの介在領域について＝＝＝
セパレータ４０は正極用電極材１２ｐと負極用電極材１２ｎの直接的な短絡を防止しつつ、充放電反応に寄与するリチウムイオンを透過させる機能を備えている。上記各実施例に示したような水平ドープ方式による蓄電素子では、負極（１０ａｎ〜１０ｄｎ）側にリチウム金属２０が貼着されているため、このリチウム金属２０が正極（１０ａｐ〜１０ｄｐ）側の集電体シート１１ｐの導電体表面に接触しない構造とする必要がある。したがって、セパレータ４０の介在領域は、対向配置された正極（１０ａｐ〜１０ｄｐ）と負極（１０ａｎ〜１０ｄｎ）におけるそれぞれの電極材（１２ｐ，１２ｎ）の塗布領域（１４ｐ，１４ｎ）に加え、リチウム金属２０の貼着領域、すなわち負極（１０ａｎ〜１０ｄｎ）の未塗布領域１７ｎにも介在している必要がある。また、多層構造とした場合、図１０に示すように、セパレータ４１が各極の電極材（１２ｐ，１２１ｎ，１２２ｎ）の領域のみに介在する場合、ある層（３１，３２）に貼着されたリチウム金属（２１，２２）から電解液中に溶け出したリチウムイオンが他の層（３２，３１）の負極用電極材（１２２ｎ，１２１ｎ）に吸蔵されてしまう可能性（図中、矢印１００で示した拡散経路）もある。したがって、安全性の確保とともに、リチウムイオンの吸蔵量を正確に制御する、という目的から、本発明では、セパレータの介在領域についても規定し、その領域を、対向配置される正極と負極の平面領域において、少なくとも外部端子部を除く領域より広い領域、すなわち、一組の正極と負極とからなる発電要素において、少なくとも負極側の塗布領域と未塗布領域とを含めた平面領域、としている。
=== About the Intervening Region of the Separator ===
The separator 40 has a function of transmitting lithium ions contributing to the charge / discharge reaction while preventing a direct short circuit between the positive electrode material 12p and the negative electrode material 12n. In the energy storage device by the horizontal doping method as shown in each of the above embodiments, the lithium metal 20 is attached to the negative electrode (10an to 10dn) side. Therefore, the lithium metal 20 is collected on the positive electrode (10ap to 10dp) side. It is necessary to have a structure that does not contact the conductor surface of the electrical sheet 11p. Therefore, the intervening region of the separator 40 includes the lithium metal 20 in addition to the application regions (14p, 14n) of the respective electrode materials (12p, 12n) in the positive electrode (10ap-10dp) and the negative electrode (10an-10dn) arranged opposite to each other. It is necessary to intervene also in the non-application area | region 17n of a sticking area | region, ie, negative electrode (10an-10dn). Further, in the case of a multi-layer structure, as shown in FIG. 10, when the separator 41 is interposed only in the region of the electrode material (12p, 121n, 122n) of each electrode, it is adhered to a certain layer (31, 32). Lithium ions dissolved into the electrolyte from the lithium metal (21, 22) may be occluded by the negative electrode material (122n, 121n) of the other layer (32, 31) (in the figure, indicated by an arrow 100) There is also a diffusion path shown). Therefore, for the purpose of ensuring safety and accurately controlling the amount of occlusion of lithium ions, the present invention also defines the intervening region of the separator, and the region is defined as the planar region of the positive electrode and the negative electrode that are arranged to face each other. , At least a region wider than the region excluding the external terminal portion, that is, a planar region including at least a negative electrode side coating region and an uncoated region in a power generation element composed of a pair of positive electrode and negative electrode.
＝＝＝外部端子部の幅や数について＝＝＝
上述したように、第２の実施例に掛かる蓄電素子では、大面積化が可能であり、大容量化に適している。確かに、第１の実施例においても、集電体シート（１１ｐ，１１ｎ）において、外部端子部（１３ｐ，１３ｎ）が形成されている辺（１５ｐ，１５ｎ）の延長方向（上下方向）にサイズを拡大すれば、大面積化が可能である。しかし、外部端子部（１３ｐ，１３ｎ）に接続されるリード板７０のサイズには制限があり、自ずと、外部端子部（１３ｐ，１３ｎ）の上下幅は、自身が設けられている集電体シート（１１ｐ，１１ｎ）の辺（１５ｐ，１５ｎ）の長さに対して短くなる。図１１に示すように、第１および第２の実施例のように、外部端子部（１３ｐ，１３ｎ）を反対方向に凸設させる場合、電流５４は、対向する極の端子部（１３ｎ，１３ｐ）に向かって流れる。このとき、集電体シート（１１ｐ，１１ｎ）における外部端子部（１３ｐ，１３ｎ）がある辺（１５ｐ，１５ｎ）の長さ（Ｈｐ，Ｈｎ）に対し、外部端子部（１３ｐ，１３ｎ）の幅（Ｌｐ，Ｌｎ）が短いと、外部端子部（１３ｐ，１３ｎ）の基部（５５ｐ，５５ｎ）に電流５４が集中する。特に、急速充放電時などにおいて大電流が流れる場合で、集電体シート（１１ｐ，１１ｎ）の上下の辺（１５ｐ，１６ｐ、および１５ｎ，１６ｎ）の長さ（Ｈｐ，Ｈｎ）に対して左右の辺（１８ｐ，１８ｎ）の長さ（Ｗｐ，Ｗｎ）が短い場合、外部端子部（１３ｐ，１３ｎ）の基部（５５ｐ，５５ｎ）に集中する電流５４の密度が極めて高くなり、この部分にリチウム金属が析出しやすくなる。そこで、集電体シート（１１ｐ，１１ｎ）において、外部端子部（１３ｐ，１３ｎ）の幅（Ｌｐ，Ｌｎ）とそれが凸設されている辺（１５ｐ，１５ｎ）の幅（Ｈｐ，Ｈｎ）とについて検討した結果、集電体シート（１１ｐ，１１ｎ）の辺（１５ｐ，１５ｎ）に対して外部端子部（１３ｐ，１３ｎ）の幅（Ｌｐ，Ｌｎ）が１／３より小さいと、リチウム金属が析出する場合があった。したがって、集電体シート（１１ｐ，１１ｎ）において、外部端子部（１３ｐ，１３ｎ）が設けられている辺（１５ｐ，１５ｎ）の長さ（Ｈｐ，Ｈｎ）に対し、それに直交する辺（１９ｐ、１８ｎ）の長さ（Ｗｐ，Ｗｎ）が短い場合では、外部端子部（１３ｐ，１３ｎ）の幅（Ｌｐ，Ｌｎ）は、当該外部端子部（１３ｐ，１３ｎ）が設けられている辺（１５ｐ，１５ｎ）の長さ（Ｈｐ，Ｈｎ）の１／３以上であることが望ましい。すなわち、Ｌｐ≧Ｈｐ、かつＬｎ≧Ｈｐであることが望ましい。
=== About the width and number of external terminals ===
As described above, the electric storage element according to the second embodiment can be increased in area and is suitable for increasing the capacity. Certainly, also in the first embodiment, the current collector sheets (11p, 11n) are sized in the extending direction (vertical direction) of the sides (15p, 15n) where the external terminal portions (13p, 13n) are formed. The area can be increased by expanding. However, there is a limit to the size of the lead plate 70 connected to the external terminal portions (13p, 13n), and the vertical width of the external terminal portions (13p, 13n) is naturally the current collector sheet on which it is provided. It becomes shorter with respect to the length of the side (15p, 15n) of (11p, 11n). As shown in FIG. 11, when the external terminal portions (13p, 13n) are projected in the opposite direction as in the first and second embodiments, the current 54 is supplied to the terminal portions (13n, 13p) of the opposite poles. ) At this time, the width of the external terminal portion (13p, 13n) with respect to the length (Hp, Hn) of the side (15p, 15n) with the external terminal portion (13p, 13n) in the current collector sheet (11p, 11n) When (Lp, Ln) is short, the current 54 concentrates on the base portions (55p, 55n) of the external terminal portions (13p, 13n). In particular, when a large current flows at the time of rapid charge / discharge, etc., it is left and right with respect to the length (Hp, Hn) of the upper and lower sides (15p, 16p, and 15n, 16n) of the current collector sheet (11p, 11n). When the side (18p, 18n) has a short length (Wp, Wn), the density of the current 54 concentrated on the base portion (55p, 55n) of the external terminal portion (13p, 13n) becomes extremely high. Metal is likely to precipitate. Therefore, in the current collector sheet (11p, 11n), the width (Lp, Ln) of the external terminal portion (13p, 13n) and the width (Hp, Hn) of the side (15p, 15n) on which the protrusion is provided. As a result, the width (Lp, Ln) of the external terminal portion (13p, 13n) is smaller than 1/3 with respect to the sides (15p, 15n) of the current collector sheet (11p, 11n). In some cases, precipitation occurred. Therefore, in the current collector sheet (11p, 11n), the side (19p, 11n) orthogonal to the length (Hp, Hn) of the side (15p, 15n) where the external terminal portion (13p, 13n) is provided. When the length (Wp, Wn) of 18n) is short, the width (Lp, Ln) of the external terminal portion (13p, 13n) is the side (15p, 13n) provided with the external terminal portion (13p, 13n). It is desirable that it is 1/3 or more of the length (Hp, Hn) of 15n). That is, it is desirable that Lp ≧ Hp and Ln ≧ Hp.
なお、１枚の集電体シート（１１ｐ，１１ｎ）に設けられる外部端子部（１３ｐ，１３ｎ）の数は、一つとは限らない。集電体シート（１１ｐ，１１ｎ）を安価な市販品で調達する場合などでは、例えば、図１２に示すように、一辺に二つの外部端子部（１３ｐ，１３ｎ）が設けられている場合もある。もちろん、三つ以上の場合もあり得る。しかし、このように複数の外部端子部（１３ｐ，１３ｎ）が設けられていても、各極における複数の外部端子部（１３ｐ，１３ｎ）の幅の合計（Ｌｐ１＋Ｌｐ２，Ｌｎ１＋Ｌｎ２）が、当該端子部（１３ｐ，１３ｎ）が形成されている辺の長さ（Ｈｐ、Ｈｎ）の１／３以上であれば、電流集中によるリチウム金属の析出を確実に防止することができる。 Note that the number of external terminal portions (13p, 13n) provided on one current collector sheet (11p, 11n) is not limited to one. In the case where the current collector sheet (11p, 11n) is procured as an inexpensive commercial product, for example, as shown in FIG. 12, there are cases where two external terminal portions (13p, 13n) are provided on one side. . Of course, there may be more than two cases. However, even if the plurality of external terminal portions (13p, 13n) are provided in this way, the total width (Lp1 + Lp2, Ln1 + Ln2) of the plurality of external terminal portions (13p, 13n) in each pole is the terminal portion ( If it is 1/3 or more of the side length (Hp, Hn) in which 13p, 13n) is formed, lithium metal precipitation due to current concentration can be reliably prevented.
＝＝＝負極用電極材の粒度分布＝＝＝
本発明の実施例における蓄電素子は、上述したように、水平ドープ方式の特徴である製造容易性を達成しつつ、極めて安全性の高い構造となっている。そして、さらに、エージング期間の短縮化を図りつつ、目的とする量のリチウムイオンを精度良く、かつ均一に負極用電極材中に吸蔵させることができれば、工業製品として十分に市場に受け入れられる蓄電素子を得ることができる。そこで、本発明では、エージング期間の短縮化を達成し、リチウムイオンを均一かつ精度良く拡散させるために、負極用電極材を塗布可能なスラリー状にする以前の粉体について最適な条件を規定した。
=== Particle size distribution of electrode material for negative electrode ===
As described above, the power storage device according to the embodiment of the present invention has a highly safe structure while achieving the manufacturability that is characteristic of the horizontal dope method. Further, if the target amount of lithium ions can be occluded accurately and uniformly in the electrode material for the negative electrode while shortening the aging period, the storage element can be sufficiently accepted in the market as an industrial product. Can be obtained. Therefore, in the present invention, in order to achieve a shortening of the aging period and to diffuse lithium ions uniformly and accurately, the optimum conditions for the powder before forming a negative electrode material into a slurry form that can be applied are defined. .
当該条件を規定するために、まず、リチウムイオンが負極用電極材中に拡散していく際に粉体の粒度がどのように影響するのかについて考察した。そして、粒子径が細かすぎると、リチウムイオンの拡散経路が密になり、リチウムイオンが拡散するまでに時間が掛かる。また、大きすぎると、充放電反応に関わる負極用電極材の表面積が小さくなり大容量化を阻害する、という点に着目した。そして、図１３に示したような、横軸に粉体としての負極用電極材の粒径（μｍ）、縦軸に各粒径の粉体の量（出現頻度：％）を取った粒度分布において、小さい粒子からの累積量（累積度数）が１６％、５０％、８４％のそれぞれとなるときの粒子径をそれぞれＤ１６、Ｄ５０、Ｄ８４としたとき、標準偏差ＳＤ＝（Ｄ８４−Ｄ１６）／２をＤ５０で除算した値（ＳＤ／Ｄ５０）を求め、この値ＳＤ／Ｄ５０に基づいて上記条件を規定することとした。なお、図１３に示したグラフ２００では、（ＳＤ／Ｄ５０，Ｄ５０）＝（０．６４，６．３０μｍ）の粒度分布２０１と、（ＳＤ／Ｄ５０，Ｄ５０）＝（０．９６，４．３６μｎ）の粒度分布２０２を例示した。 In order to define the conditions, first, it was considered how the particle size of the powder affects when lithium ions diffuse into the negative electrode material. If the particle diameter is too small, the lithium ion diffusion path becomes dense, and it takes time until the lithium ions diffuse. Moreover, when it was too large, it paid attention to the point that the surface area of the electrode material for negative electrodes in connection with charging / discharging reaction will become small, and capacity | capacitance will be inhibited. As shown in FIG. 13, the particle size distribution in which the horizontal axis represents the particle size (μm) of the negative electrode material as powder and the vertical axis represents the amount of powder having each particle size (appearance frequency:%). , The standard deviation SD = (D84−D16) / where D16, D50 and D84 are the particle diameters when the cumulative amount (cumulative frequency) from small particles is 16%, 50% and 84%, respectively. A value obtained by dividing 2 by D50 (SD / D50) was obtained, and the above condition was defined based on this value SD / D50. In the graph 200 shown in FIG. 13, the particle size distribution 201 of (SD / D50, D50) = (0.64, 6.30 μm) and (SD / D50, D50) = (0.96, 4.36 μn). ) Is exemplified.
上記粒度分布において、ＳＤ／Ｄ５０の値が大きい場合は、粒子径が広範囲に分布し、かつ細かい粒子が多いことを意味する。また、Ｄ５０は中央値で、このＤ５０の粒径より小さな粒子と大きな粒子とがちょうど同量となることを意味し、このＤ５０の値があまり大きいと急速充放電には適さない。そして、以上の考察に基づいて、実際に、ＳＤ／Ｄ５０、およびＤ５０の値が異なる各種負極用電極材を使用して、蓄電素子を作成しリチウムイオンの拡散状態を調べた。当該調査に際しては、図１に示した実施例１の正極と負極を用いた１層の積層体からなる蓄電素子を作成し、その蓄電素子を２週間エージングさせた後に負極におけるリチウム金属に対する電位を測定することでリチウムイオンの拡散状態の良否を判断した。リチウムイオンが拡散された状態では、負極の電位は、２．０Ｖとなる。なお、負極におけるリチウム金属と貼着領域と負極用電極材の塗布領域との距離を９０ｍｍとし、負極用電極材の塗布領域を１８０ｍｍ×１８０ｍｍの略矩形とした。そして、その矩形の両端に帯状のリチウム金属を貼着した。 In the above particle size distribution, when the value of SD / D50 is large, it means that the particle diameter is distributed over a wide range and there are many fine particles. Further, D50 is a median value, meaning that particles having a particle size smaller than that of D50 and large particles have the same amount. If the value of D50 is too large, it is not suitable for rapid charge / discharge. And based on the above consideration, the electrical storage element was actually produced using the electrode material for negative electrodes from which the value of SD / D50 and D50 differed, and the diffusion state of lithium ion was investigated. In the investigation, a power storage element composed of a single layer laminate using the positive electrode and the negative electrode of Example 1 shown in FIG. 1 was prepared, and after aging the power storage element for 2 weeks, the potential with respect to lithium metal in the negative electrode was changed. The quality of the lithium ion diffusion state was judged by measurement. In the state where lithium ions are diffused, the potential of the negative electrode is 2.0V. In addition, the distance between the lithium metal in the negative electrode, the adhesion region, and the application region of the negative electrode material was 90 mm, and the application region of the negative electrode material was a substantially rectangular shape of 180 mm × 180 mm. And the strip | belt-shaped lithium metal was stuck to the both ends of the rectangle.
以下の表１に当該調査結果を示した。
上述したように、Ｄ５０の値が大きいと急速充放電に向かないため、当該調査では、Ｄ５０≦８（μｍ）の負極用電極材について調査した。そして、表１の結果から、ＳＤ／Ｄ５０の値が０．９以下であればリチウムイオンが良好に拡散することが判明した。もちろん、極めて速い充放電速度が要求されないのであれば、Ｄ５０の値が大きな負極用電極材を使用しても問題ない。本発明では、リチウム金属が拡散された状態、すなわち負極におけるリチウム金属に対する電位が２．０Ｖ以下の蓄電素子において、ＳＤ／Ｄ５０≦０．９の条件が必要条件となる。 As described above, when the value of D50 is large, it is not suitable for rapid charge / discharge. Therefore, in this investigation, the electrode material for negative electrode with D50 ≦ 8 (μm) was investigated. From the results shown in Table 1, it was found that if the SD / D50 value is 0.9 or less, lithium ions diffuse well. Of course, if a very fast charge / discharge rate is not required, there is no problem even if a negative electrode material having a large D50 value is used. In the present invention, the condition of SD / D50 ≦ 0.9 is a necessary condition in the state where lithium metal is diffused, that is, in the electric storage element in which the potential with respect to the lithium metal in the negative electrode is 2.0 V or less.
また、電流は、エッジ、すなわち角（かど）に集中することから、リチウム金属の析出は、負極側の塗布領域やその形状に加え、粉体自体の形状についても考慮する必要がある。そして、粉体の形状を球にすることで、粉体の形状に起因するリチウム金属の析出も防止できることが判明した。 In addition, since the current is concentrated at the edge, that is, at the corner, the deposition of lithium metal needs to take into consideration the shape of the powder itself in addition to the coating region and its shape on the negative electrode side. And it became clear that precipitation of the lithium metal resulting from the shape of a powder can also be prevented by making the shape of a powder into a sphere.
１０ａｐ〜１０ｄｐ 正極
１０ｎ、１０ａｎ〜１０ｄｎ 負極
１１ｐ、１１ｎ 集電体
１２ｐ 正極用電極材
１２ｎ、１２１ｎ、１２２ｎ 負極用電極材
１３ｐ、１３ｎ 外部端子部
１４ｐ 正極用電極材の塗布領域
１４ｎ 負極用電極材の塗布領域
１７ｐ、１７ｎ 未塗布領域
２０、２１、２２ リチウム金属
３０ａ〜３０ｄ、３１、３２ １単位の積層体
４０、４１ セパレータ
６０ａ、１６０ 多層構造の積層体
10ap to 10dp Positive electrode 10n, 10an to 10dn Negative electrode 11p, 11n Current collector 12p Positive electrode material 12n, 121n, 122n Negative electrode material 13p, 13n External terminal portion 14p Positive electrode material coating region 14n Negative electrode material Coated region 17p, 17n Uncoated region 20, 21, 22 Lithium metal 30a-30d, 31, 32 Laminate of one unit 40, 41 Separator 60a, 160 Multilayered laminate
Claims (6)
前記正極は、一辺に外部端子部が凸設された略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンもしくはアニオンを可逆的に担持可能な正極用電極材が塗布されてなり、
前記負極は、一辺に外部端子部が凸設された前記略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンの吸蔵・放出が可能な負極用電極材が塗布されてなり、
正極側の前記塗布領域は、前記略矩形状のシート状集電体において、少なくとも前記外部端子部を除く領域であり、
負極側の前記塗布領域は、前記略矩形状のシート状集電体の４辺において、前記外部端子部が凸設された辺と当該辺に平行な辺のうち、少なくとも一辺に沿って帯状に設けられた未塗布領域と前記外部端子部の領域以外の領域であり、
前記正極側の塗布領域は、前記発電要素において対向配置される前記負極側の塗布領域より内側であり、
前記リチウムイオンは、前記帯状の未塗布領域に貼着されたリチウム金属を起源として負極用電極材中に拡散することで負極側に吸蔵され、
前記セパレータは、前記発電要素において、少なくとも負極側の塗布領域と未塗布領域とを含めた平面領域に介在し、
前記発電要素において、前記負極の電位は、前記リチウムイオンが拡散されている状態で２．０Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以下であり、
前記負極用電極材は、粉体から形成され、当該粉体の粒度分布において、粒子径の小さな方から累積して１６％、５０％、８４％のそれぞれの量に対応する粒子径をそれぞれＤ１６と、Ｄ５０、Ｄ８０とした際に、（Ｄ８４−Ｄ１６）／（２×Ｄ５０）≦０．９である
ことを特徴とする非水蓄電素子。 An electrode laminate formed by laminating one unit or more of a unit of power generation element in which a sheet-like positive electrode and a negative electrode are opposed to each other with a separator interposed therebetween is hermetically sealed together with an electrolyte containing a lithium salt, and on the negative electrode side. A non-aqueous storage element in which lithium ions originating from lithium metal are previously occluded,
The positive electrode is coated with a positive electrode material capable of reversibly carrying lithium ions or anions in a coating region provided on the surface of a substantially rectangular sheet-like current collector having an external terminal portion protruding on one side. And
In the negative electrode, a negative electrode material capable of occluding and releasing lithium ions is applied to a coating region provided on the surface of the substantially rectangular sheet-like current collector having an external terminal portion protruding on one side. Become
The application area on the positive electrode side is an area excluding at least the external terminal portion in the substantially rectangular sheet-shaped current collector,
The coating area on the negative electrode side is in a strip shape along at least one side of the four sides of the substantially rectangular sheet-shaped current collector among the side where the external terminal portion is projected and the side parallel to the side. It is a region other than the uncoated region provided and the region of the external terminal part,
The application region on the positive electrode side is inside the application region on the negative electrode side that is opposed to the power generation element,
The lithium ions are occluded on the negative electrode side by diffusing into the negative electrode material starting from the lithium metal adhered to the strip-shaped uncoated region,
In the power generation element, the separator is interposed in a planar region including at least a negative electrode side coating region and an uncoated region,
In the power generation element, the potential of the negative electrode is 2.0 V (vs. Li / Li + ) or less in a state where the lithium ions are diffused.
The negative electrode material is formed from powder, and in the particle size distribution of the powder, the particle diameter corresponding to each of 16%, 50%, and 84% accumulated from the smaller particle diameter is D16. And when it is set as D50 and D80, it is (D84-D16) / (2 * D50) <= 0.9. The nonaqueous electrical storage element characterized by the above-mentioned.
前記略矩形状のシート状集電体において、前記外部端子部が形成される側の辺およびこれに平行する辺は、当該辺に直交する辺より長く、
前記凸状の外部端子部は、シート状集電体に１つ以上凸設され、自身が形成される側の辺の長さＨと、当該辺に平行な自身における辺の長さの合計Ｌとが、３Ｌ≧Ｈである
ことを特徴とする請求項１に記載の非水蓄電素子。 In the power generation element, the positive electrode and the negative electrode are arranged to face each other so that each external terminal portion protrudes in the opposite direction,
In the substantially rectangular sheet-shaped current collector, the side on which the external terminal portion is formed and the side parallel to the side are longer than the side orthogonal to the side,
One or more of the convex external terminal portions are provided so as to protrude from the sheet-like current collector, and the total length L of the side on the side where the convex external terminal is formed and the side length of the side parallel to the side. The non-aqueous storage element according to claim 1, wherein 3L ≧ H.
正極は、一辺に外部端子部が凸設された略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンもしくはアニオンを可逆的に担持可能な正極用電極材が塗布されてなり、
負極は、一辺に外部端子部が凸設された前記略矩形状のシート状集電体の表面に設けられた塗布領域にリチウムイオンの吸蔵・放出が可能な負極用電極材が塗布されてなり、
正極側の前記塗布領域は、前記略矩形状のシート状集電体において、少なくとも前記外部端子部を除く領域であり、
前記略矩形状のシート状集電体の４辺において、前記外部端子部が凸設された辺と直交する２辺のそれぞれに沿う２つの帯状の領域とこれら２辺に平行でシート状集電体を横断する帯状の領域のうち、少なくとも一つの領域を未塗布領域として、負極側の前記塗布領域は、当該未塗布領域と前記外部端子部の領域以外の領域であり、
前記正極側の塗布領域は、前記発電要素において対向配置される前記負極側の塗布領域より内側であり、
前記リチウムイオンは、前記帯状の未塗布領域に貼着されたリチウム金属を起源として負極用電極材中に拡散することで負極側に吸蔵され、
前記セパレータは、前記発電要素において、少なくとも負極側の塗布領域と未塗布領域とを含めた平面領域に介在し、
前記発電要素において、負極の電位は、前記リチウムイオンが拡散されている状態でリチウム金属に対して２．０Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）以下であり、
前記負極用電極材は、粉体から形成され、当該粉体の粒度分布において、粒子径の小さな方から累積して１６％、５０％、８４％のそれぞれの量に対応する粒子径をそれぞれＤ１６と、Ｄ５０、Ｄ８０とした際に、（Ｄ８４−Ｄ１６）／（２×Ｄ５０）≦０．９である
ことを特徴とする非水蓄電素子。 A power generation element in which a sheet-like positive electrode and a negative electrode are disposed to face each other with a separator as a unit, and an electrode laminate formed by laminating at least one unit of power generation elements is hermetically sealed together with an electrolyte containing a lithium salt And a non-aqueous storage element in which lithium ions originating from lithium metal are previously diffused into the negative electrode,
In the positive electrode, a positive electrode material capable of reversibly carrying lithium ions or anions is applied to a coating region provided on the surface of a substantially rectangular sheet-like current collector having an external terminal projecting on one side. Become
The negative electrode is formed by applying a negative electrode material capable of occluding and releasing lithium ions to a coating region provided on the surface of the substantially rectangular sheet-like current collector having an external terminal projecting on one side. ,
The application area on the positive electrode side is an area excluding at least the external terminal portion in the substantially rectangular sheet-shaped current collector,
On the four sides of the substantially rectangular sheet-like current collector, two strip-shaped regions along each of two sides orthogonal to the side on which the external terminal portion is projected, and a sheet-like current collector parallel to these two sides. Among the strip-shaped regions crossing the body, at least one region is an uncoated region, and the coated region on the negative electrode side is a region other than the uncoated region and the region of the external terminal portion,
The application region on the positive electrode side is inside the application region on the negative electrode side that is opposed to the power generation element,
The lithium ions are occluded on the negative electrode side by diffusing into the electrode material for the negative electrode from the lithium metal adhered to the band-shaped uncoated region,
In the power generation element, the separator is interposed in a planar region including at least a negative electrode side coating region and an uncoated region,
In the power generation element, the potential of the negative electrode is 2.0 V (vs. Li / Li + ) or less with respect to lithium metal in a state where the lithium ions are diffused.
The negative electrode material is formed from powder, and in the particle size distribution of the powder, the particle diameter corresponding to each of 16%, 50%, and 84% accumulated from the smaller particle diameter is D16. And, when D50 and D80, (D84−D16) / (2 × D50) ≦ 0.9.
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