JP2019091615A - Nonaqueous electrolyte secondary battery - Google Patents

Nonaqueous electrolyte secondary battery Download PDF

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JP2019091615A
JP2019091615A JP2017219383A JP2017219383A JP2019091615A JP 2019091615 A JP2019091615 A JP 2019091615A JP 2017219383 A JP2017219383 A JP 2017219383A JP 2017219383 A JP2017219383 A JP 2017219383A JP 2019091615 A JP2019091615 A JP 2019091615A
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JP7015447B2 (en
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井上　直樹
Naoki Inoue
直樹 井上
昭人 田野井
Akihito Tanoi
昭人 田野井
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GS Yuasa Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
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Abstract

To provide a high capacity nonaqueous electrolyte secondary battery having high initial efficiency.SOLUTION: In a nonaqueous electrolyte secondary battery including a positive electrode plate having a positive electrode active material layer on a positive electrode collector, and a negative electrode plate having a negative electrode active material layer on a negative electrode collector, the negative electrode active material layer includes a first negative electrode active material layer including a positive electrode facing part, i.e., a region facing the positive electrode active material layer, and a positive electrode non-facing part, i.e., a region not facing the positive electrode active material layer, and placed in the positive electrode facing part, and a second negative electrode active material layer placed, at least partially, in the positive electrode non-facing part, in a state touching mutually, the negative electrode active material layer in the region facing the positive electrode active material layer contains SiO, and in the negative electrode active material layer in the region not facing the positive electrode active material layer, the mass ratio of SiOcontained in the active material of the active material layer is smaller than that of the negative electrode active material layer in the region facing the positive electrode active material layer.SELECTED DRAWING: Figure 4

Description

本発明は、非水電解質二次電池に関する。   The present invention relates to a non-aqueous electrolyte secondary battery.

リチウム二次電池に代表される非水電解質二次電池は、エネルギー密度が高く、携帯用端末、ハイブリッド自動車等に広く用いられており、近年では、電気自動車の駆動用電源にも使用されている。電気自動車については、航続距離が短いことが普及の障壁となっており、航続距離の向上のために搭載する非水電解質二次電池の充放電容量の向上が不可欠である。現在実用化されている非水電解質二次電池においては、負極活物質に炭素材料が、正極活物質にリチウム遷移金属酸化物が、主に用いられている。   Non-aqueous electrolyte secondary batteries represented by lithium secondary batteries have high energy density and are widely used in portable terminals, hybrid vehicles and the like, and in recent years are also used as driving power sources for electric vehicles . With regard to electric vehicles, a short cruising distance is a barrier to widespread use, and it is essential to improve the charge and discharge capacity of non-aqueous electrolyte secondary batteries to be mounted for the improvement of cruising distance. In non-aqueous electrolyte secondary batteries currently put to practical use, a carbon material is mainly used as a negative electrode active material, and a lithium transition metal oxide is mainly used as a positive electrode active material.

充放電容量をさらに向上させるため、炭素材料の理論容量を超えるエネルギー密度を有する負極材料が求められており、Ｓｉを構成元素とする金属、合金、又は化合物を負極活物質として用いることが検討されている。
Ｓｉを構成元素に含む負極活物質は、Ｌｉイオンと固溶体や金属間化合物を形成することにより、Ｌｉイオンを多量に貯蔵することができる。なかでも、一般式ＳｉＯｘで表される、Ｓｉ及びＳｉＯ２がミクロに相分離した状態で存在する活物質は、約１５００ｍＡｈ／ｇと、従来の炭素材料の約４倍もの容量を示すことから、高容量非水電解質二次電池の負極材料として期待されている。 In order to further improve the charge and discharge capacity, a negative electrode material having an energy density exceeding the theoretical capacity of the carbon material is required, and the use of a metal, an alloy or a compound containing Si as a constituent element is examined. ing.
The negative electrode active material containing Si as a constituent element can store a large amount of Li ions by forming a solid solution or an intermetallic compound with Li ions. Among them, the active material represented by the general formula SiO x and present in the state of microphase separation of Si and SiO 2 has a capacity of about 1500 mAh / g, which is about four times that of the conventional carbon material. It is expected as a negative electrode material for high capacity non-aqueous electrolyte secondary batteries.

ＳｉＯｘ負極活物質は、初回充放電時に不可逆容量を生じる。このため、ＳｉＯｘ負極活物質を用いた非水電解質二次電池の初期効率（初回充放電時のクーロン効率）は、約７５％と、炭素材料を負極活物質に用いた場合に比べて低いことが知られている。また、ＳｉＯｘ負極活物質は、充放電時の体積膨張・収縮が大きいこと、及び充放電サイクルに伴う容量低下が大きいことも知られている。こうした短所を改善するため、これまでに種々の対策が講じられている（特許文献１〜３）。 The SiO x negative electrode active material produces an irreversible capacity at the time of initial charge and discharge. Therefore, the initial efficiency (Coulomb efficiency at the time of first charge and discharge) of the non-aqueous electrolyte secondary battery using the SiO x negative electrode active material is about 75%, which is lower than when the carbon material is used for the negative electrode active material It is known. In addition, it is also known that the SiO x negative electrode active material has a large volumetric expansion and contraction during charge and discharge, and a large capacity decrease due to the charge and discharge cycle. Various measures have been taken so far to remedy these disadvantages (Patent Documents 1 to 3).

特許文献１には、「集電体と、前記集電体の表面中央部に形成された、リチウムと合金化しうる元素を含有する負極活物質を含む負極活物質層と、を有するリチウムイオン二次電池用負極であって、前記負極活物質層の外周縁部に、当該外周縁部からの前記負極活物質の滑落を防止するための滑落防止手段を備えることを特徴とする、リチウムイオン二次電池用負極。」（請求項１）、及び「前記滑落防止手段として、前記集電体の表面であって前記負極活物質層の外周部に形成された、前記負極活物質層よりもヤング率の小さい緩衝層を有する、請求項１に記載のリチウムイオン二次電池用負極。」（請求項２）が記載されている。
また、段落［００３０］には、「図２に示すように、本実施形態における負極は、集電体１１と、当該集電体の表面中央部に形成された負極活物質層１５とを有する。図２に示す形態において、負極活物質層１５は、リチウムと合金化しうる元素であるケイ素（Ｓｉ）を含有する負極活物質（合金系負極活物質）である酸化ケイ素（ＳｉＯ）を含む。」との記載があり、段落［００３１］には、「そして、集電体１１の表面の負極活物質層１５の外周部には、負極活物質層１５よりも厚さの大きい緩衝層２３が形成されている。緩衝層２３は、導電助剤として、アセチレンブラック（ＡＢ）を含む。また、これに加えて、緩衝層２３は、バインダとして、スチレン−ブタジエンゴム（ＳＢＲ）およびカルボキシメチルセルロース（ＣＭＣ）を含む。かような構成によって、緩衝層２３のヤング率は負極活物質層１５のヤング率よりも小さくなるように制御されている。」との記載があり、段落［００４２］には、「緩衝層２３は、上述した合金系負極活物質以外の負極活物質（つまり、リチウムと合金化しうる元素を含まない負極活物質）を含んでもよい。かような負極活物質の具体的な種類については、従来公知の知見が適宜参照されうる。例えば、活性炭、グラファイト、ハードカーボンなどの炭素材料・・・・が、負極活物質として緩衝層２３に含まれうる。これらの負極活物質が緩衝層２３に含まれることで、電池の容量密度の低下を最小限に抑制しつつ、合金系負極活物質の膨張収縮に起因する当該活物質の滑落を効果的に防止することが可能である。」との記載がある。
そして、実施例には、導電助剤であるアセチレンブラック（ＡＢ）（９０質量部）及びバインダであるポリイミド（ＰＩ）（１０質量部）、並びに導電助剤であるアセチレンブラック（ＡＢ）（８５質量部）、スチレン−ブタジエンゴム（ＳＢＲ）（９質量部）及びカルボキシメチルセルロース（ＣＭＣ）（６質量部）を、それぞれスラリー粘度調整溶媒であるＮ−メチル−２−ピロリドン（ＮＭＰ）の適量に対して添加して調製した緩衝層形成用スラリーを用いて、負極集電体である銅箔の表面外周縁部に緩衝層を形成した後、該緩衝層の内部領域全体に、合金系負極活物質である酸化ケイ素（ＳｉＯ）（平均粒子径：８μｍ）（８５質量部）及びバインダであるポリイミド（ＰＩ）（１５質量部）を、スラリー粘度調整溶媒であるＮ−メチル−２−ピロリドン（ＮＭＰ）の適量に対して添加して調製した負極活物質スラリーを用いて負極活物質層を形成して負極を完成させたことが記載されている。（段落［００９０］〜［００９６］） Patent Document 1 discloses that “a lithium ion dialysate having a current collector and a negative electrode active material layer formed in the center of the surface of the current collector and containing a negative electrode active material containing an element that can be alloyed with lithium. It is a negative electrode for a secondary battery, wherein an outer peripheral edge portion of the negative electrode active material layer is provided with a sliding prevention means for preventing the sliding of the negative electrode active material from the outer peripheral edge portion. A negative electrode for a secondary battery. (Claim 1), and "as the sliding prevention means, the Younger than the negative electrode active material layer formed on the surface of the current collector and at the outer peripheral portion of the negative electrode active material layer. The negative electrode for a lithium ion secondary battery according to claim 1, which has a buffer layer having a small ratio.
Further, in the paragraph [0030], “as shown in FIG. 2, the negative electrode in the present embodiment has a current collector 11 and a negative electrode active material layer 15 formed in the center of the surface of the current collector. 2, the negative electrode active material layer 15 contains silicon oxide (SiO) which is a negative electrode active material (alloy-based negative electrode active material) containing silicon (Si) which is an element capable of alloying with lithium. In the paragraph [0031], “and in the outer peripheral portion of the negative electrode active material layer 15 on the surface of the current collector 11, the buffer layer 23 having a thickness larger than that of the negative electrode active material layer 15 is The buffer layer 23 contains acetylene black (AB) as a conductive aid, and additionally, the buffer layer 23 contains styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders. ) According to such a configuration, the Young's modulus of the buffer layer 23 is controlled to be smaller than the Young's modulus of the negative electrode active material layer 15. "is described in paragraph [0042]. The layer 23 may contain a negative electrode active material (that is, a negative electrode active material not containing an element that can be alloyed with lithium) other than the alloy-based negative electrode active material described above. For example, carbon materials such as activated carbon, graphite, hard carbon, etc. may be included in the buffer layer 23 as a negative electrode active material, for example. It is possible to effectively prevent the sliding of the active material caused by the expansion and contraction of the alloy-based negative electrode active material, while minimizing the decrease in capacity density of the battery. There is a description of
And in an example, acetylene black (AB) (90 mass parts) which is a conductive support agent, polyimide (PI) (10 mass parts) which is a binder, and acetylene black (AB) which is a conductive support agent (85 mass) Parts), styrene-butadiene rubber (SBR) (9 parts by mass) and carboxymethylcellulose (CMC) (6 parts by mass) with respect to the appropriate amount of N-methyl-2-pyrrolidone (NMP), which is a slurry viscosity adjusting solvent. After the buffer layer is formed on the outer peripheral edge of the surface of the copper foil as the negative electrode current collector using the slurry for buffer layer formation prepared by addition, an alloy-based negative electrode active material is formed over the entire internal region of the buffer layer. A certain silicon oxide (SiO) (average particle size: 8 μm) (85 parts by mass) and polyimide (PI) (15 parts by mass) as a binder -2-pyrrolidone using the negative electrode active material slurry was prepared by adding with respect to an appropriate amount of (NMP) to form the anode active material layer that completed the negative electrode is described. (Paragraphs [0090] to [0096])

特許文献２には、「正極集電体の表面に正極活物質を含む正極活物質層が形成されてなる正極と、負極集電体の表面にケイ素含有負極活物質を含む負極活物質層が形成されてなる負極と、セパレータと、を含む単電池層を含む発電要素を有する電気デバイスであって、前記発電要素を構成する前記単電池層の少なくとも１つにおいて、前記負極活物質層の面積をＡ［ｍ２］とし、前記正極活物質層の面積をＣ［ｍ２］としたときに、式（１）：０．９１≦Ｃ／Ａ＜１を満足する、電気デバイス。」（請求項１）、及び「前記式（１）を満足する前記単電池層において、前記負極活物質層が、下記式（４）
［数３］
α（Ｓｉ材料）＋β（炭素材料） （４）
式中、Ｓｉ材料は、アモルファスＳｉＯ２粒子とＳｉ粒子との混合体であるＳｉＯｘ（ｘはＳｉの原子価を満足する酸素数を表す）およびＳｉ含有合金からなる群から選択される１種または２種以上であり、αおよびβは負極活物質層における各成分の重量％を表し、８０≦α＋β≦９８、３≦α≦４０、４０≦β≦９５である、
で表される負極活物質を含有する、請求項１〜３のいずれか１項に記載の電気デバイス。」（請求項４）が記載されている。
また、段落［００９９］〜［０１００］には、「従来、一般に、リチウムイオン二次電池等の電気デバイスでは、負極におけるリチウムデンドライトの生成や正負極間での対向ずれといった不具合を抑制してデバイスの性能を向上させる目的で、負極活物質層のサイズを一回り大きく設計することが行われている。本発明者らの検討では、従来このように行われている設計によると、負極活物質層のサイズが正極活物質層に比して相対的に大き過ぎることで、ケイ素含有負極活物質を用いた場合にサイクル耐久性が低下することが判明した。これは、ケイ素含有負極活物質の有する不可逆容量が大きいことに起因するものである。具体的には、不可逆容量の大きいケイ素含有負極活物質を用いて充放電を行うと、充電時において、負極活物質層の正極活物質層と対向した領域（正極対向領域）に吸蔵されたＬｉが正極活物質層と対向していない領域（正極非対向領域）へと拡散して不可逆化することがある。このような不可逆化は、充放電容量に本来は寄与しないはずの正極非対向領域における不可逆容量によってＬｉが消費されることを意味する。このため、せっかく潜在的に大きな電気容量を有するケイ素含有負極活物質を用いても、最終的に取り出せる電池容量は低下してしまうことが判明したのである。
これに対し、本実施形態のようにＣ／Ａの値を制御すると、充電の際に負極活物質に吸蔵されたＬｉが負極活物質層の正極対向領域から正極非対向領域へと移動することによる不可逆化が抑制される。その結果、充放電サイクルの進行に伴う電池容量の低下が防止され、サイクル耐久性に優れた電気デバイスが提供される。」との記載がある。
そして、実施例には、負極活物質としてＳｉＯｘを１．００重量部及び黒鉛を８．４５重量部、導電助剤としてＳｕｐｅｒＰを０．２０重量部、バインダとしてポリフッ化ビニリデン（ＰＶＤＦ）を０．３５重量部、並びに溶媒としてＮ−メチル−２−ピロリドン（ＮＭＰ）を１０．０重量部含む負極用スラリーを用いて作製した、活物質層面積が縦２．６ｃｍ×横２．１ｃｍ（実施例１）、縦２．５５ｃｍ×横２．０５ｃｍ（実施例２）又は縦２．５２５ｃｍ×横２．０２ｃｍ（実施例３）の負極、及び活物質層面積が縦２．５ｃｍ×横２．０ｃｍの正極を備えた発電要素を作製したことが記載されている（段落［０１６１］〜［０１７０］，［０１７３］〜［０１７５））。 In Patent Document 2, “a positive electrode having a positive electrode active material layer formed on the surface of a positive electrode current collector, and a negative electrode active material layer containing a silicon-containing negative electrode active material on the surface of the negative electrode current collector An electric device having a power generation element including a unit cell layer including a negative electrode formed and a separator, wherein at least one of the unit cell layers constituting the power generation element, an area of the negative electrode active material layer An electric device satisfying the formula (1): 0.91 ≦ C / A <1 where A [m 2 ] and an area of the positive electrode active material layer is C [m 2 ]. Item 1), and “In the unit cell layer satisfying the formula (1), the negative electrode active material layer has a formula (4)
[Equation 3]
α (Si material) + β (carbon material) (4)
In the formula, the Si material is a single species selected from the group consisting of SiO x (x represents an oxygen number satisfying the valence of Si), which is a mixture of amorphous SiO 2 particles and Si particles, and Si-containing alloys And α and β each represent weight% of each component in the negative electrode active material layer, and 80 ≦ α + β ≦ 98, 3 ≦ α ≦ 40, and 40 ≦ β ≦ 95.
The electric device of any one of Claims 1-3 containing the negative electrode active material represented by these. "(Claim 4) is described.
Also, in paragraphs [0099] to [0100], “In the prior art, generally, in electrical devices such as lithium ion secondary batteries, problems such as generation of lithium dendrite at the negative electrode and displacement between positive and negative electrodes are suppressed In order to improve the performance of the negative electrode active material layer, the size of the negative electrode active material layer is designed to be one size larger. It was found that the cycle durability is lowered when the silicon-containing negative electrode active material is used because the size of the layer is relatively large compared to the positive electrode active material layer. Specifically, when charge and discharge are performed using a silicon-containing negative electrode active material having a large irreversible capacity, the negative electrode active material is charged during charging. Li absorbed in a region facing the positive electrode active material layer (positive electrode facing region) may diffuse into a region not facing the positive electrode active material layer (positive electrode non-facing region) to become irreversible. Irreversibility means that Li is consumed by the irreversible capacity in the positive electrode non-facing area which should not originally contribute to the charge and discharge capacity, and thus the silicon-containing negative electrode active material having a potentially large electric capacity. It has been found that the battery capacity that can be finally taken out is reduced even if
On the other hand, when the value of C / A is controlled as in the present embodiment, Li absorbed in the negative electrode active material during charge moves from the positive electrode facing region to the positive electrode non-facing region from the negative electrode active material layer. Irreversible due to As a result, a decrease in battery capacity with the progress of charge and discharge cycles can be prevented, and an electrical device with excellent cycle durability can be provided. There is a statement with ".
In the example, 1.00 parts by weight of SiO x and 8.45 parts by weight of graphite as a negative electrode active material, 0.20 parts by weight of SuperP as a conductive additive, and polyvinylidene fluoride (PVDF) as a binder 0 The active material layer area was 2.6 cm long × 2.1 cm wide (implementation using an anode slurry containing .35 parts by weight and 10.0 parts by weight of N-methyl-2-pyrrolidone (NMP) as a solvent). Example 1) A negative electrode of 2.55 cm × 2.05 cm (Example 2) or 2.525 cm × 2.02 cm (Example 3), and an active material layer area of 2.5 cm × 2.5 ×. It is described that a power generation element provided with a 0 cm positive electrode was produced (Paragraphs [0161] to [0170], [0173] to [0175]).

特許文献３には、「リチウム二次電池の負極活物質層用の負極活物質であって、前記負極活物質は、ケイ素系材料（ＳｉＯｘ：０．５≦ｘ≦１．６）を含有し、Ｘ線光電子分光法から得られるＳｉ１ｓ波形において結合エネルギーが５２０ｅＶ以上、５３７ｅＶ以下の範囲に少なくとも２つ以上のピークを有するものであることを特徴とする負極活物質。」（請求項１）、及び「前記少なくとも２つ以上のピークは、ＳｉＯ２、Ｌｉ４ＳｉＯ４、Ｌｉ２ＳｉＯ３、Ｌｉ２Ｏ、Ｌｉ２ＣＯ３、Ｌｉ２Ｓｉ２Ｏ５、Ｌｉ２Ｓｉ２Ｏ３から選ばれる少なくとも２種以上に起因するピークであることを特徴とする請求項１に記載の負極活物質。」（請求項２）が記載されている。
また、段落［００４７］〜［００４８］には、「２つ以上のピークが上記範囲内とすることで、ケイ素酸化物内に生成するＳｉＯ２成分の一部をＬｉ化合物へ選択的に変更することができる。
２つ以上のピークが、ＳｉＯ２、Ｌｉ４ＳｉＯ４、Ｌｉ２ＳｉＯ３、Ｌｉ２Ｏ、Ｌｉ２ＣＯ３、Ｌｉ２Ｓｉ２Ｏ５、Ｌｉ２Ｓｉ２Ｏ３から選ばれる少なくとも２種以上に起因するピークであることが好ましい。
その中でも２つ以上のピークが、Ｌｉ４ＳｉＯ４、Ｌｉ２ＳｉＯ３、Ｌｉ２ＣＯ３、Ｌｉ２Ｏから選ばれる少なくとも２種以上に起因するピークである場合に、特に良い特性を示す。
選択的化合物（Ｌｉ化合物）の作成方法としては、電気化学法を用いることが好ましい。
電気化学法において、リチウム対極に対する電位規制や電流規制などの条件を変更することで選択的化合物の作製が可能となる。また、選択的化合物は一部電気化学法により生成した後に、炭酸雰囲気下、又は、酸素雰囲気下などで乾燥させることでより緻密な物質を得られる。
電気化学法による改質回数は特に限定しないが、１度のリチウム挿入及び一部離脱よりも複数回リチウム挿入及び一部離脱を行う方がより安定的な物質生成が可能である。この時、挿入電位／電流、離脱電位／電流、改質回数は、負極活物質の特性改善と密接な関係を有している。」との記載がある。
そして、実施例には、金属ケイ素と二酸化ケイ素を混合した原料を反応炉中で気化させて吸着板上に堆積させ、冷却後粉砕した粉末に必要に応じて熱分解ＣＶＤで炭素層を被覆し、電気化学法のＬｉ挿入離脱法を用いてバルク内改質を行って作製した、ＳｉＯ２、Ｌｉ４ＳｉＯ４、Ｌｉ２ＳｉＯ３等を含む負極活物質を備えたリチウム二次電池が記載されている（段落［０１１４］，［０１２３］，［０１２７］，表２，３等）。 In Patent Document 3, “the negative electrode active material for a negative electrode active material layer of a lithium secondary battery, the negative electrode active material contains a silicon-based material (SiO x : 0.5 ≦ x ≦ 1.6) Further, in the Si1s waveform obtained from X-ray photoelectron spectroscopy, the negative electrode active material is characterized by having at least two or more peaks in a range of 520 eV or more and 537 eV or less. And “the at least two or more peaks are selected from SiO 2 , Li 4 SiO 4 , Li 2 SiO 3 , Li 2 O, Li 2 CO 3 , Li 2 Si 2 O 5 , Li 2 Si 2 O 3 The negative electrode active material according to claim 1, characterized in that the peak is at least two or more kinds of peaks.
Furthermore, in paragraphs [0047] to [0048], “a part of the SiO 2 component formed in the silicon oxide is selectively changed to the Li compound by setting the two or more peaks within the above range. be able to.
Two or more peaks are at least two or more selected from SiO 2 , Li 4 SiO 4 , Li 2 SiO 3 , Li 2 O, Li 2 CO 3 , Li 2 Si 2 O 5 , and Li 2 Si 2 O 3 It is preferable that it is a peak attributable.
Among them, particularly good characteristics are exhibited when two or more peaks are peaks attributed to at least two or more selected from Li 4 SiO 4 , Li 2 SiO 3 , Li 2 CO 3 , and Li 2 O.
It is preferable to use an electrochemical method as a method of producing the selective compound (Li compound).
In the electrochemical method, selective compounds can be produced by changing conditions such as potential regulation and current regulation with respect to the lithium counter electrode. In addition, a selective compound can be partially produced by an electrochemical method and then dried in a carbonic acid atmosphere, an oxygen atmosphere, or the like to obtain a denser substance.
Although the number of times of modification by the electrochemical method is not particularly limited, more stable material formation can be achieved by performing lithium insertion and partial release several times rather than one lithium insertion and partial release. At this time, the insertion potential / current, the separation potential / current, and the number of times of modification have a close relationship with the characteristic improvement of the negative electrode active material. There is a statement with ".
Then, in the example, a raw material in which metal silicon and silicon dioxide are mixed is vaporized in a reaction furnace and deposited on an adsorption plate, and a powder after cooling is coated with a carbon layer by pyrolysis CVD as needed. Describe a lithium secondary battery comprising a negative electrode active material containing SiO 2 , Li 4 SiO 4 , Li 2 SiO 3 or the like, which is prepared by performing in-bulk modification using the Li insertion and release method of the electrochemical method (Paragraphs [0114], [0123], [0127], Tables 2, 3 etc.).

非水電解質二次電池における充放電サイクルに伴う容量低下対策としては、負極活物質層内で電位を異ならせることも知られている（特許文献４，５）。   It is also known that the potential is made different in the negative electrode active material layer as a measure for the capacity reduction due to the charge and discharge cycle in the non-aqueous electrolyte secondary battery (Patent Documents 4 and 5).

特許文献４には、「正極集電体と、前記正極集電体に保持された正極活物質層と、負極集電体と、前記負極集電体に保持され、前記正極活物質層を覆う負極活物質層と、前記正極活物質層と前記負極活物質層との間に介在したセパレータとを備え、前記負極活物質層は、前記正極活物質層に対向している部位の平衡電位Ｅａが、前記正極活物質層に対向していない部位の平衡電位Ｅｂよりも高い（Ｅａ＞Ｅｂ）、二次電池。」（請求項１）及び「負極活物質層は、前記正極活物質層に対向している部位と、前記正極活物質層に対向していない部位とで、異なる負極活物質が用いられている、請求項１に記載された二次電池。」（請求項２）が記載されている。
また、段落［００７６］には、「このように、正極活物質層２２３に対向している部位２４３ａと、正極活物質層２２３に対向していない部位２４３ｂ１、２４３ｂ２とで、異なる負極活物質を用いることによって、平衡電位に差が生じる。リチウムイオン二次電池１００の負極活物質には、例えば、天然黒鉛、人造黒鉛、天然黒鉛や人造黒鉛のアモルファスカーボンなどの黒鉛（炭素系材料）を用いることができる。かかる黒鉛は、種類によって負極活物質層の平衡電位が異なる。例えば、負極活物質層の平衡電位を異ならせるのに寄与する黒鉛として、易黒鉛化炭素（soft carbon）や、難黒鉛化性炭素（hard carbon）や、黒鉛質材料（graphite）がある。」との記載があり、段落［００８０］には、「本発明者の知見によれば、負極活物質に易黒鉛化性炭素を用いた場合は、負極活物質に難黒鉛化性炭素や黒鉛質材料を用いた場合よりも負極活物質層２４３の平衡電位が高くなる。また、負極活物質層に難黒鉛化性炭素を用いた場合は、負極活物質に黒鉛質材料を用いた場合よりも負極活物質層２４３の平衡電位が高くなる。」との記載がある。
そして、作用効果を評価するための試験電池として、正極活物質層に対向している部位に易黒鉛化性炭素を備え、正極活物質層に対向していない部位に黒鉛質材料ないし難黒鉛化性炭素を備えた負極シート、及び正極活物質層に対向している部位に難黒鉛化性炭素を備え、正極活物質層に対向していない部位に黒鉛質材料を備えた負極シート、をそれぞれ備えた試験電池が記載されている（段落［００９４］〜［００９５］，［００９８］，表１）。 In Patent Document 4, “a positive electrode current collector, a positive electrode active material layer held by the positive electrode current collector, a negative electrode current collector, and the negative electrode current collector are held to cover the positive electrode active material layer. A negative electrode active material layer, and a separator interposed between the positive electrode active material layer and the negative electrode active material layer, the negative electrode active material layer having an equilibrium potential Ea of a portion facing the positive electrode active material layer Is higher than the equilibrium potential Eb of a portion not facing the positive electrode active material layer (Ea> Eb), the secondary battery (claim 1) and “the negative electrode active material layer is formed on the positive electrode active material layer The secondary battery according to claim 1, wherein different negative electrode active materials are used in a portion facing to each other and a portion not facing to the positive electrode active material layer. It is done.
Further, in the paragraph [0076], “A different negative electrode active material is thus selected for the portion 243 a facing the positive electrode active material layer 223 and the portions 243 b 1 and 243 b 2 not facing the positive electrode active material layer 223. As a negative electrode active material of the lithium ion secondary battery 100, for example, graphite (carbon-based material) such as natural graphite, artificial graphite, natural graphite or amorphous carbon of artificial graphite is used as a negative electrode active material of the lithium ion secondary battery 100. Such graphite has different equilibrium potentials of the negative electrode active material layer depending on its type, for example, as a graphite that contributes to making the equilibrium potential of the negative electrode active material layer different, it is difficult to graphitizable carbon (soft carbon) or There is a description that “graphitizable carbon (hard carbon) and graphitic material (graphite) are included”, and in paragraph [0080], “the present inventors found that the negative electrode active material is easily black. When carbonized carbon is used, the equilibrium potential of the negative electrode active material layer 243 is higher than when non-graphitizable carbon or a graphitic material is used as the negative electrode active material. In the case of using carbon, the equilibrium potential of the negative electrode active material layer 243 is higher than that in the case of using a graphite material for the negative electrode active material.
Then, as a test battery for evaluating the function and effect, the portion facing the positive electrode active material layer is provided with graphitizable carbon, and the portion not facing the positive electrode active material layer is a graphitic material or non-graphitizing A negative electrode sheet provided with an insulating carbon, and a negative electrode sheet provided with non-graphitizable carbon at a portion facing the positive electrode active material layer, and a graphitic material at a portion not facing the positive electrode active material layer; Test batteries provided are described (paragraphs [0094] to [0095], [0098], Table 1).

特許文献５には、「正極集電体上に正極活物質層を有する正極板と、負極集電体上に負極活物質層を有する負極板とを備える非水電解質二次電池において、前記負極活物質層が、第１負極活物質で形成された第１負極活物質層と、第２負極活物質で形成された第２負極活物質層とを相互に接触した状態で含み、前記第１負極活物質層が、前記正極活物質層と対向する領域に配置されており、前記第２負極活物質層の少なくとも一部が、前記正極活物質層と対向していない領域に配置されており、前記第１負極活物質と前記第２負極活物質が示すＳＯＣ−ＯＣＰ曲線をプロットした際に、少なくとも一つのＳＯＣ値Ｘにおいて、当該ＳＯＣ値Ｘに対応する前記第１負極活物質のＯＣＰ値が、当該ＳＯＣ値Ｘに対応する前記第２負極活物質のＯＣＰ値よりも大きい値を示す、非水電解質二次電池。」（請求項１）が記載されている。
また、段落［００３１］には、「第１負極活物質および第２負極活物質の組み合わせの例として、好ましくは、第１負極活物質が非晶質炭素であり、第２負極活物質が黒鉛である組み合わせ、更に好ましくは第１負極活物質が易黒鉛化性炭素であり、第２負極活物質が黒鉛である組み合わせが挙げられる。」との記載がある。
そして、実施例には、第１負極活物質として易黒鉛化炭素、第２負極活物質として黒鉛を使用した負極板を備えた非水電解質二次電池が記載されている（段落［００４９］〜［００５７］）。 Patent Document 5 describes “a non-aqueous electrolyte secondary battery comprising: a positive electrode plate having a positive electrode active material layer on a positive electrode current collector, and a negative electrode plate having a negative electrode active material layer on a negative electrode current collector; The active material layer includes a first negative electrode active material layer formed of a first negative electrode active material and a second negative electrode active material layer formed of a second negative electrode active material in a mutually contacting state, A negative electrode active material layer is disposed in a region facing the positive electrode active material layer, and at least a portion of the second negative electrode active material layer is disposed in a region not facing the positive electrode active material layer. The OCP value of the first negative electrode active material corresponding to the SOC value X in at least one SOC value X when plotting the SOC-OCP curves represented by the first negative electrode active material and the second negative electrode active material Is the OC of the second negative electrode active material corresponding to the SOC value X Shows a value greater than the value, a non-aqueous electrolyte secondary battery. "(Claim 1) is described.
Also, in paragraph [0031], “As an example of the combination of the first negative electrode active material and the second negative electrode active material, preferably, the first negative electrode active material is amorphous carbon, and the second negative electrode active material is graphite. And the combination of the first negative electrode active material is graphitizable carbon and the second negative electrode active material is graphite.
Then, a non-aqueous electrolyte secondary battery including a negative electrode plate using graphitizable carbon as a first negative electrode active material and graphite as a second negative electrode active material is described in Examples (paragraphs [0049] [0057]).

特開２０１０−１７６９８０号公報JP, 2010-176980, A ＷＯ２０１５／１１１１８７WO2015 / 111187 特開２０１５−１１１５４７号公報JP, 2015-11547, A ＷＯ２０１２／１０５０５２WO2012 / 105052 特開２０１５−６４９７５号公報JP, 2015-64975, A

ＳｉＯｘ負極活物質の短所のうち、初期効率が低い点については、初回のＬｉ吸蔵時に、活物質中のＳｉＯ２とＬｉ＋との反応により、不可逆成分であるＬｉ４ＳｉＯ４が生成することが原因として考えられている（特許文献２の段落［０００８］）。 Among the disadvantages of the SiO x negative electrode active material, regarding the low initial efficiency, the reaction between SiO 2 in the active material and Li + generates Li 4 SiO 4 which is an irreversible component at the time of the first Li absorption. Is considered to be the cause (paragraph [0008] of Patent Document 2).

特許文献１，２には、ＳｉＯｘ負極活物質を用いた非水電解質二次電池の初期効率を向上させることについての記載はなく、負極活物質層内で活物質の組成を変えることも開示されていない。 Patent Documents 1 and 2 do not describe improving the initial efficiency of a non-aqueous electrolyte secondary battery using a SiO x negative electrode active material, and also disclose changing the composition of the active material in the negative electrode active material layer. It has not been.

特許文献３には、ＳｉＯｘ負極活物質を用いたリチウム二次電池の初回効率向上について記載されているが、初回効率向上のための手段は、活物質中にＬｉ４ＳｉＯ４やＬｉ２ＳｉＯ３等の化合物を生成させることであり、負極活物質層内で活物質の組成を変えることは開示されていない。 Although Patent Document 3 describes the improvement of the initial efficiency of a lithium secondary battery using a SiO x negative electrode active material, the means for improving the initial efficiency is to use Li 4 SiO 4 or Li 2 SiO in the active material. No. 3 is to form a compound, and changing the composition of the active material in the negative electrode active material layer is not disclosed.

特許文献４，５には、非水電解質二次電池の初期効率を向上させることについての記載はなく、また負極活物質にＳｉＯｘを用いた非水電解質二次電池は具体的に示されていない。 Patent Documents 4 and 5 do not describe improving the initial efficiency of a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery using SiO x as a negative electrode active material is specifically shown. Absent.

本発明は、高容量で初期効率の高い非水電解質二次電池を提供することを課題とする。   An object of the present invention is to provide a non-aqueous electrolyte secondary battery having a high capacity and a high initial efficiency.

上記課題を解決するために、本発明の一側面は、「正極集電体上に正極活物質層を有する正極板と、負極集電体上に負極活物質層を有する負極板とを備える非水電解質二次電池であって、前記負極活物質層が、前記正極活物質層に対向する領域である正極対向部と、前記正極活物質層に対向していない領域である正極非対向部とを備え、前記正極対向部に配置された第１負極活物質層と、前記正極非対向部に少なくとも一部が配置された第２負極活物質層とを相互に接触した状態で含み、前記正極活物質層に対向する領域が備える負極活物質層は、ＳｉＯｘを備え、前記正極活物質層に対向していない領域が備える負極活物質層は、活物質層の活物質が含有するＳｉＯｘの質量比率が、前記正極活物質層に対向する領域が備える負極活物質層よりも小さい、非水電解質二次電池」を採用する。 In order to solve the above problems, one aspect of the present invention is “a positive electrode plate having a positive electrode active material layer on a positive electrode current collector, and a negative electrode plate having a negative electrode active material layer on a negative electrode current collector. A water electrolyte secondary battery, wherein the negative electrode active material layer is a positive electrode facing portion which is a region facing the positive electrode active material layer, and a positive electrode non-facing portion which is a region not facing the positive electrode active material layer. And the first positive electrode active material layer disposed in the positive electrode facing portion and the second negative electrode active material layer disposed at least in part in the positive electrode non-facing portion in mutually contacting state, the positive electrode The negative electrode active material layer provided in the region facing the active material layer comprises SiO x, and the negative electrode active material layer provided in the region not facing the positive electrode active material layer comprises SiO x contained in the active material of the active material layer A negative electrode active material provided in a region in which the mass ratio of the component faces the positive electrode active material layer To adopt a small, non-aqueous electrolyte secondary battery "than.

本発明によれば、高容量で初期効率の高い非水電解質二次電池を提供することができる。   According to the present invention, it is possible to provide a non-aqueous electrolyte secondary battery with high capacity and high initial efficiency.

充放電サイクル前後のＳｉＯｘ−黒鉛混合負極のＸＡＦＳプロファイルXAFS profile of SiO x -graphite mixed negative electrode before and after charge and discharge cycle 本実施形態に係る非水電解質二次電池の一例である、角形非水電解質二次電池の概略斜視図Schematic perspective view of a square non-aqueous electrolyte secondary battery which is an example of the non-aqueous electrolyte secondary battery according to the present embodiment 本実施形態に係る非水電解質二次電池における、正極板及び負極板の位置関係を示す概略断面図1 is a schematic cross-sectional view showing the positional relationship between the positive electrode plate and the negative electrode plate in the non-aqueous electrolyte secondary battery according to the present embodiment. 本実施形態に係る非水電解質二次電池における、負極活物質層の構造及び配置を示す概略断面図1 is a schematic cross-sectional view showing the structure and arrangement of a negative electrode active material layer in the non-aqueous electrolyte secondary battery according to the present embodiment. 本実施形態における第１負極活物質層と第２負極活物質層とが相互に接触した状態を示す概略断面図A schematic sectional view showing a state in which the first negative electrode active material layer and the second negative electrode active material layer in the present embodiment are in contact with each other 本実施形態に係る非水電解質二次電池における、第１負極活物質層及び第２負極活物質層の配置例を示す概略断面図1 is a schematic cross-sectional view showing an arrangement example of a first negative electrode active material layer and a second negative electrode active material layer in the non-aqueous electrolyte secondary battery according to the present embodiment. 本実施形態に係る非水電解質二次電池を複数個集合した蓄電装置を示す概略図Schematic which shows the electrical storage apparatus which gathered two or more non-aqueous electrolyte secondary batteries which concern on this embodiment

本発明の構成及び作用効果について、技術的思想を交えて説明する。但し、作用機構については推定を含んでおり、その正否は、本発明を制限するものではない。また、以下の実施形態における構成要素のうち、最上位概念を示す独立請求項に記載されていない構成要素については、任意の構成要素として説明される。   The configuration and effects of the present invention will be described together with technical ideas. However, the mechanism of action includes presumption, and its correctness does not limit the present invention. Moreover, among the components in the following embodiments, components not described in the independent claim showing the highest level concept are described as optional components.

本発明者は、上述した課題を解決するための調査及び検討の過程で、ＳｉＯｘを含む負極について、充放電サイクル前後のＸ線吸収微細構造解析（Ｘ−ｒａｙ Ａｂｓｏｒｐｔｉｏｎ Ｆｉｎｅ Ｓｔｒｕｃｔｕｒｅ：ＸＡＦＳ）を行い、図１に示す結果を得た。この結果から、ＳｉＯｘを含む負極では、充放電サイクルの初期においては、不可逆成分であるＬｉ４ＳｉＯ４だけでなく、ＳｉＯ２とＬｉ＋とが反応してＬｉ４ＳｉＯ４を生成する過程における中間生成物であるＬｉ２ＳｉＯ３及び未反応のＳｉＯ２も存在していること、並びに充放電サイクルを繰り返すとＬｉ４ＳｉＯ４の割合が増加し、反対にＬｉ２ＳｉＯ３及びＳｉＯ２の割合は減少することが判明した。このことは、初回数サイクルの充放電だけでは、Ｌｉ４ＳｉＯ４は完全に生成しきっておらず、充放電サイクルの繰り返しによりＳｉＯ２やＬｉ２ＳｉＯ３から徐々にＬｉ４ＳｉＯ４が生成することを示唆している。ＳｉＯ２やＬｉ２ＳｉＯ３からＬｉ４ＳｉＯ４が生成する反応は、Ｌｉ＋を消費する反応であるため、ＳｉＯｘを含む負極を備える非水電解質二次電池の初期数サイクルにおける低い効率は、Ｌｉ４ＳｉＯ４の生成によるＬｉ＋の消費に起因するものと考えられる。 The inventor conducted an X-ray absorption fine structure (XAFS) analysis before and after charge and discharge cycles on a negative electrode containing SiO x in the process of research and study for solving the problems described above. The results shown in FIG. 1 were obtained. From this result, in the negative electrode containing SiO x , not only the irreversible component Li 4 SiO 4 but also SiO 2 and Li + react with each other in the process of producing Li 4 SiO 4 at the beginning of the charge and discharge cycle. The intermediate product Li 2 SiO 3 and unreacted SiO 2 are also present, and when the charge and discharge cycle is repeated, the proportion of Li 4 SiO 4 increases, and conversely, the proportions of Li 2 SiO 3 and SiO 2 Was found to decrease. This is only charging and discharging of the first number of cycles, Li 4 SiO 4 is not completely full generation, gradually Li 4 that SiO 4 is generated from SiO 2 and Li 2 SiO 3 by repeated charge and discharge cycles It suggests. Since the reaction to form Li 4 SiO 4 from SiO 2 or Li 2 SiO 3 is a reaction that consumes Li + , the low efficiency in the initial few cycles of the nonaqueous electrolyte secondary battery provided with the negative electrode containing SiO x is It is believed that this is due to the consumption of Li + due to the formation of Li 4 SiO 4 .

一般に、非水電解質二次電池の負極は、正極に比べて面積を広くし、正極非対向部を有するように設計される。これは、正極非対向部が存在しない場合、正負極の対向位置が非水電解質二次電池製造時にわずかでもずれた際に、有効面積が低下するだけでなく、Ｌｉ電析が生じやすくなり安全性が低下する虞があるためである。非水電解質二次電池の充電時には、負極の正極対向部にＬｉ＋が吸蔵されるが、吸蔵されたＬｉ＋の一部は正極非対向部へと拡散する。この正極非対向部に拡散したＬｉ＋は、対向する正極が存在しないため、放電時に正極に戻り難い。すなわち、負極中にＬｉ＋がトラップされることになるため、放電容量が低下する原因となる。
負極活物質がＳｉＯｘの場合には、充放電サイクルの初期に正極非対向部において上述したＬｉ＋を消費する反応が進行するため、正極対向部に吸蔵されたＬｉ＋の正極非対向部への拡散が促進されると共に、正極非対向部に拡散したＬｉ＋が放電時に正極に一層戻り難くなる結果、従来の炭素材料よりも初期数サイクルにおける効率の低下が顕著になると考えられる。 Generally, the negative electrode of a non-aqueous electrolyte secondary battery is designed to have a larger area than the positive electrode and have a positive electrode non-facing portion. This is because, in the absence of the positive electrode non-facing portion, not only the effective area is reduced but also the lithium electrodeposition tends to occur when the facing position of the positive and negative electrodes is slightly deviated at the time of manufacturing the non-aqueous electrolyte secondary battery. It is because there is a possibility that the sex may decrease. During charging of the nonaqueous electrolyte secondary battery, the positive electrode opposed part of the negative electrode Li + is but is occluded, a portion of the Li + occluded diffuses to the positive electrode non-facing portion. Since Li + diffused to the positive electrode non-facing portion does not have a facing positive electrode, it does not easily return to the positive electrode during discharge. That is, since Li + is trapped in the negative electrode, the discharge capacity is reduced.
When the negative electrode active material is SiO x , the above-described reaction of consuming Li + proceeds in the positive electrode non-facing portion at the beginning of the charge / discharge cycle, so the positive electrode non-facing portion of Li + absorbed in the positive electrode facing portion As a result, Li + diffused in the positive electrode non-facing portion becomes more difficult to return to the positive electrode during discharge, and therefore, it is considered that the efficiency drop in the initial few cycles becomes remarkable compared to the conventional carbon material.

そこで、本発明者は、負極の正極非対向部にＳｉＯｘ以外の負極活物質を含む負極活物質層を配置すれば、上述したＬｉ＋を消費する反応によるＬｉ＋の消費量が減少し、初期効率の低下を抑制できると考え、本発明を完成するに至った。 The present inventor has by arranging the anode active material layer containing a negative electrode active material other than SiO x in the positive electrode non-facing portion of the negative electrode, the consumption of Li + by reactions consuming the Li + as described above is reduced, The present invention has been completed, considering that the reduction of the initial efficiency can be suppressed.

以下、本発明の一実施形態（以下、「本実施形態」という）に係る非水電解質二次電池について、図面を参照しつつ説明する。   Hereinafter, a non-aqueous electrolyte secondary battery according to an embodiment of the present invention (hereinafter, referred to as "this embodiment") will be described with reference to the drawings.

［非水電解質二次電池の全体構造］
本実施形態の非水電解質二次電池は、正極集電体上に正極活物質層を有する正極板と、負極集電体上に負極活物質層を有する負極板とを備えている。当該正極板と負極板との間にはセパレータが介在されて電極群が形成され、上記電極群は非水電解質と共に電池ケースに収納される。 [Overall structure of non-aqueous electrolyte secondary battery]
The non-aqueous electrolyte secondary battery of the present embodiment includes a positive electrode plate having a positive electrode active material layer on a positive electrode current collector, and a negative electrode plate having a negative electrode active material layer on a negative electrode current collector. A separator is interposed between the positive electrode plate and the negative electrode plate to form an electrode group, and the electrode group is housed in the battery case together with the non-aqueous electrolyte.

図２に、本実施形態の一例として、角形非水電解質二次電池の概略斜視図を示す。なお、本実施形態に係る非水電解質二次電池の構成についてはこれに限定されない。電極群は、それぞれ１枚の正極板、負極板、及びセパレータが積層され、断面円形状、又は断面略楕円形状に捲回されて構成されたものを採用できる。あるいは、それぞれ複数枚の正極板、負極板、及びセパレータが積層されて構成されたものを採用できる。そして、上記電極群を収納し、円筒型電池、扁平型電池、角型電池、等とすることができる。
図２に、本発明に係る非水電解質二次電池の一実施形態である矩形状の非水電解質二次電池１の概略図を示す。なお、同図は、容器内部を透視した図としている。図２に示す非水電解質二次電池１は、電極群２が電池容器３に収納されている。電極群２は、正極活物質を備える正極と、負極活物質を備える負極とが、セパレータを介して捲回されることにより形成されている。正極は、正極リード４’を介して正極端子４と電気的に接続され、負極は、負極リード５’を介して負極端子５と電気的に接続されている。 FIG. 2 shows a schematic perspective view of a square non-aqueous electrolyte secondary battery as an example of the present embodiment. The configuration of the non-aqueous electrolyte secondary battery according to the present embodiment is not limited to this. As the electrode group, it is possible to adopt one in which one positive electrode plate, one negative electrode plate, and one separator are stacked and wound in a circular cross section or a substantially elliptical cross section. Alternatively, it is possible to employ one configured by laminating a plurality of positive electrode plates, negative electrode plates, and separators. And the said electrode group can be accommodated and it can be set as a cylindrical battery, a flat battery, a square battery, etc.
FIG. 2 shows a schematic view of a rectangular non-aqueous electrolyte secondary battery 1 which is an embodiment of the non-aqueous electrolyte secondary battery according to the present invention. In addition, the same figure is a view seen through the inside of the container. The electrode group 2 of the non-aqueous electrolyte secondary battery 1 shown in FIG. The electrode group 2 is formed by winding a positive electrode including a positive electrode active material and a negative electrode including a negative electrode active material via a separator. The positive electrode is electrically connected to the positive electrode terminal 4 through the positive electrode lead 4 ′, and the negative electrode is electrically connected to the negative electrode terminal 5 through the negative electrode lead 5 ′.

［正極板と負極板の構造及び配置］
図３及び図４に、本実施形態の非水電解質二次電池における、正極板及び負極板の構造及び配置の概略断面図を示す。図３は、正極板及び負極板の位置関係を説明しており、図４は、負極活物質層の構造及び配置を説明している。図３に示すように、本実施形態の非水電解質二次電池は、正極集電体６１上に正極活物質層６２を有する正極板６、及び負極集電体７１上に負極活物質層７２を有する負極板７を備え、負極集電体７１上の負極活物質層７２は、正極活物質層６２と対向する領域（正極対向部）７２ａと、正極活物質層６２に対向しない領域（正極非対向部）７２ｂとを備える。正極対向部７２ａと正極非対向部７２ｂとの比率は、一般に非水電解質二次電池で採用されている値を採用できる。 [Structure and Arrangement of Positive and Negative Electrode Plates]
FIG. 3 and FIG. 4 show schematic cross-sectional views of the structure and arrangement of the positive electrode plate and the negative electrode plate in the non-aqueous electrolyte secondary battery of this embodiment. FIG. 3 illustrates the positional relationship between the positive electrode plate and the negative electrode plate, and FIG. 4 illustrates the structure and arrangement of the negative electrode active material layer. As shown in FIG. 3, in the non-aqueous electrolyte secondary battery of this embodiment, a positive electrode plate 6 having a positive electrode active material layer 62 on a positive electrode current collector 61, and a negative electrode active material layer 72 on a negative electrode current collector 71. The negative electrode active material layer 72 on the negative electrode current collector 71 has a region (positive electrode facing portion) 72 a facing the positive electrode active material layer 62 and a region (positive electrode not facing the positive electrode active material layer 62). Non-facing portion) 72 b. The ratio of the positive electrode facing portion 72a to the positive electrode non-facing portion 72b can adopt a value generally adopted in non-aqueous electrolyte secondary batteries.

負極活物質層７２は、図４に示すように、正極対向部７２ａに配置された第１負極活物質層７２１と、正極非対向部７２ｂに少なくとも一部が配置された第２負極活物質層７２２とを、相互に接触した状態で含む。
ここで、「相互に接触した状態」とは、機能的には、相互にリチウムイオンが伝導しうる状態で接続されていればよく、構造的には、各活物質層が層面の少なくとも一部を露出した状態で、層の端部同士が接触された状態を意味する。図５（ａ）〜（ｃ）に示すような、活物質層同士が一部重なった状態も、ここでいう「相互に接触した状態」に含まれる。
なお、図３〜図５では、便宜上、正極集電体６１及び負極集電体７１の片面に正極活物質層６２及び負極活物質層７２を設けた場合の例を挙げているが、正極活物質層６２及び負極活物質層７２は、正極集電体６１及び負極集電体７１の両面に形成されていてもよい。 As shown in FIG. 4, the negative electrode active material layer 72 is a first negative electrode active material layer 721 disposed in the positive electrode facing portion 72a, and a second negative electrode active material layer disposed at least in part in the positive electrode non-facing portion 72b. And 722 in contact with each other.
Here, “in the state of being in contact with each other” may be functionally connected as long as lithium ions can conduct each other, and structurally, each active material layer is at least a part of the layer surface Means that the ends of the layers are in contact with each other. The state in which the active material layers partially overlap each other as shown in FIGS. 5A to 5C is also included in the “state in contact with each other”.
In addition, although the example at the time of providing the positive electrode active material layer 62 and the negative electrode active material layer 72 in the single side | surface of the positive electrode collector 61 and the negative electrode collector 71 is mentioned for convenience in FIG. The material layer 62 and the negative electrode active material layer 72 may be formed on both sides of the positive electrode current collector 61 and the negative electrode current collector 71.

第１負極活物質層７２１は、正極対向部７２ａのみに配置されてもよく（図４，図６（ａ））、また正極対向部７２ａに配置されつつ、その一部が正極非対向部７２ｂに配置されてもよい（図６（ｂ），（ｃ））。
また、第２負極活物質層７２２は、正極非対向部７２ｂのみに配置されてもよく（図４，図６（ｂ），（ｃ））、また正極非対向部７２ｂに配置されつつ、その一部が正極対向部７２ａに配置されてもよい（図６（ａ））。
第２負極活物質層７２２は、非水電解質二次電池の初期効率の向上効果を高める点で、正極対向部７２ａにも配置されることが好ましい。
第１負極活物質層７２１に対する第２負極活物質層７２２の面積比率は、０．０１〜０．２が好ましく、０．０５〜０．１５がより好ましい。該比率を０．０１以上とすることで、正極非対向部の本来の機能である、Ｌｉ電析の防止効果が確実に得られ、０．２以下とすることで、高容量の非水電解質二次電池が得られる。なお、各負極活物質層の面積は、セパレータ８に対向する面に露出している部分で決定する。その際、複数の正極板、負極板、及びセパレータを積層して極板群を構成する場合は、一枚の負極板７に形成された各負極活物質層７２１及び７２２の総面積を該各活物質層の面積とし、長尺シート形状の正極板、負極板、及びセパレータを捲回して極板群を構成する場合は、長尺シート形状の負極集電体上の、幅方向に第１負極活物質層７２１及び第２負極活物質層７２２が共に形成された単位長さの領域における各負極活物質層７２１及び７２２の総面積を、該各活物質層の面積とする。 The first negative electrode active material layer 721 may be disposed only in the positive electrode facing portion 72a (FIG. 4, FIG. 6A), and a portion thereof is disposed in the positive electrode non-facing portion 72b while being disposed in the positive electrode facing portion 72a. It may be arranged in (Fig. 6 (b), (c)).
Further, the second negative electrode active material layer 722 may be disposed only in the positive electrode non-facing portion 72b (FIG. 4, FIG. 6 (b), (c)), and while being disposed in the positive electrode non-facing portion 72b A part may be disposed in the positive electrode facing portion 72a (FIG. 6 (a)).
The second negative electrode active material layer 722 is preferably disposed also on the positive electrode facing portion 72a in terms of enhancing the effect of improving the initial efficiency of the non-aqueous electrolyte secondary battery.
0.01-0.2 are preferable and, as for the area ratio of the 2nd negative electrode active material layer 722 with respect to the 1st negative electrode active material layer 721, 0.05-0.15 are more preferable. By setting the ratio to 0.01 or more, the effect of preventing lithium electrodeposition, which is the original function of the positive electrode non-facing portion, can be surely obtained, and by setting the ratio to 0.2 or less, a high capacity nonaqueous electrolyte A secondary battery is obtained. The area of each negative electrode active material layer is determined by the portion exposed on the surface facing the separator 8. At that time, in the case of forming an electrode plate group by laminating a plurality of positive electrode plates, negative electrode plates and separators, the total area of each negative electrode active material layer 721 and 722 formed on one negative electrode plate 7 is When the electrode plate group is formed by winding the long sheet-shaped positive electrode plate, the negative electrode plate, and the separator with the area of the active material layer, the first in the width direction on the long sheet-shaped negative electrode current collector The total area of each of the negative electrode active material layers 721 and 722 in the region of the unit length in which both the negative electrode active material layer 721 and the second negative electrode active material layer 722 are formed is taken as the area of each active material layer.

［負極板］
本実施形態の負極板７は、上述の構造を有すると共に、負極活物質層７２における正極対向部７２ａがＳｉＯｘを備え、負極活物質層７２における正極非対向部７２ｂの活物質が含有するＳｉＯｘの質量比率が、正極対向部７２ａよりも小さくなるよう構成される。ここで、ある領域がＳｉＯｘを「備える」とは、該領域に含まれる負極活物質の全質量に対するＳｉＯｘの質量割合が、概ね５質量％以上であることを意味する。
このように構成された負極板７の詳細を、以下に説明する。 [Anode plate]
The negative electrode plate 7 of the present embodiment has the above-described structure, and the positive electrode facing portion 72a of the negative electrode active material layer 72 includes SiO x , and the active material of the positive electrode non-facing portion 72b of the negative electrode active material layer 72 contains SiO. The mass ratio of x is configured to be smaller than that of the positive electrode facing portion 72a. Here, that "a region" includes "SiO x " means that the mass ratio of SiO x to the total mass of the negative electrode active material contained in the region is about 5% by mass or more.
The details of the negative electrode plate 7 configured in this way will be described below.

正極対向部７２ａに配置された第１負極活物質層７２１は、活物質としてＳｉＯｘを備える。ここで、ＳｉＯｘとは、アモルファス構造を有するケイ素酸化物からなる物質、又は、粒径が概ね数十ｎｍ以下であるケイ素（Ｓｉ）の結晶相が、酸化ケイ素（ＳｉＯ２）のマトリックス中に分散した構造を有する物質を意味する。従って、ＳｉＯｘのｘは、０＜ｘ＜２の範囲で種々の値を取りうる。ｘの値は、０．８≦ｘが好ましい。また、ｘ≦１．２が好ましい。ＳｉＯｘ活物質は、粒子表面が炭素材料等の導電性物質で被覆されていてもよい。また、前記ＳｉＯｘは、あらかじめＬｉをプリドープすることによって、Ｌｉ２ＳｉＯ３及びＬｉ４ＳｉＯ４、Ｌｉ２Ｓｉ２Ｏ５、Ｌｉ２Ｓｉ２Ｏ３のうち少なくとも１種以上を含有した状態でもよい。 The first negative electrode active material layer 721 disposed in the positive electrode facing portion 72a includes SiO x as an active material. Here, SiO x refers to a substance composed of silicon oxide having an amorphous structure, or a crystal phase of silicon (Si) having a particle size of about several tens of nm or less in a matrix of silicon oxide (SiO 2 ) It means a substance having a dispersed structure. Therefore, x of SiO x can take various values in the range of 0 <x <2. The value of x is preferably 0.8 ≦ x. Further, x ≦ 1.2 is preferable. In the SiO x active material, the particle surface may be coated with a conductive material such as a carbon material. The SiO x may be in a state of containing at least one or more of Li 2 SiO 3, Li 4 SiO 4 , Li 2 Si 2 O 5 , and Li 2 Si 2 O 3 by predoping Li in advance. .

第１負極活物質層７２１は、ＳｉＯｘ以外の活物質を含んでもよい。併用する負極活物質に制限はなく、例えば、Ｌｉ［Ｌｉ１／３Ｔｉ５／３］Ｏ４に代表されるスピネル型結晶構造を有するチタン酸リチウム等のチタン系材料、ＳｉやＳｂ，Ｓｎ系などの合金系材料リチウム金属、リチウム合金（リチウム−シリコン、リチウム−アルミニウム，リチウム−鉛，リチウム−スズ，リチウム−アルミニウム−スズ，リチウム−ガリウム，及びウッド合金等のリチウム金属含有合金）、リチウム複合酸化物（リチウム−チタン）の他、リチウムを吸蔵・放出可能な合金、炭素材料（例えば黒鉛（グラファイト）、難黒鉛化性炭素（ハードカーボン）及び易黒鉛化性炭素（ソフトカーボン）等）等が挙げられる。なかでも、導電性が高く不可逆容量が小さい点で、炭素材料が好ましく、黒鉛がより好ましい。
なお、本実施形態における黒鉛とは、層間距離ｄ００２が０．３４ｎｍ未満の炭素材料を指し、易黒鉛化炭素は、層間距離ｄ００２が０．３４ｎｍ以上０．３６ｎｍ未満、難黒鉛化炭素は、０．３６ｎｍ以上の炭素材料である。 The first negative electrode active material layer 721 may contain an active material other than SiO x . There is no limitation on the negative electrode active material to be used in combination, and, for example, a titanium-based material such as lithium titanate having a spinel type crystal structure represented by Li [Li 1/3 Ti 5/3 ] O 4 , Si, Sb, Sn-based Alloy materials such as lithium metal, lithium alloy (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as wood alloy), lithium composite In addition to oxides (lithium-titanium), alloys capable of absorbing and desorbing lithium, carbon materials (eg, graphite (graphite), non-graphitizable carbon (hard carbon), graphitizable carbon (soft carbon), etc.), etc. Can be mentioned. Among them, carbon materials are preferable and graphite is more preferable in terms of high conductivity and small irreversible capacity.
In the present embodiment, graphite refers to a carbon material having an interlayer distance d002 of less than 0.34 nm, graphitizable carbon having an interlayer distance d002 of 0.34 nm or more and less than 0.36 nm, and non-graphitizable carbon having 0 It is a carbon material of .36 nm or more.

第１負極活物質層７２１は、負極を高容量とする点で、活物質中のＳｉＯｘの質量比率が２０質量％以上であることが好ましく、５０質量％以上であることがより好ましい。また、充放電サイクルに伴う負極の容量低下を抑制し、非水電解質二次電池を長寿命化する点で、活物質中のＳｉＯｘの質量比率が９８質量％以下であることが好ましく、９０質量％以下であることがより好ましい。 The mass ratio of SiO x in the active material is preferably 20% by mass or more, and more preferably 50% by mass or more, from the viewpoint of increasing the capacity of the negative electrode in the first negative electrode active material layer 721. In addition, the mass ratio of SiO x in the active material is preferably 98 mass% or less, in order to suppress the capacity decrease of the negative electrode accompanying the charge and discharge cycle and extend the life of the non-aqueous electrolyte secondary battery. It is more preferable that the content is at most mass%.

正極非対向部７２ｂに少なくとも一部が配置された第２負極活物質層７２２は、含有する負極活物質中のＳｉＯｘの質量比率が、第１負極活物質層７２１よりも小さくなるように構成される。第２負極活物質層７２２における負極活物質としては、上述したＳｉＯｘ以外の活物質が使用可能であり、ＳｉＯｘを含有してもよい。ＳｉＯｘ以外の活物質としては、充放電過程でケイ酸リチウムを生じない活物質が、不可逆容量が小さい点で好ましい。なかでも、不可逆容量が特に小さく導電性も高い点で、炭素材料がより好ましく、黒鉛がさらに好ましい。第２負極活物質層７２２にＳｉＯｘよりも不可逆容量が小さい活物質を使用して、正極非対向部７２ｂの活物質が含有するＳｉＯｘの質量比率を正極対向部７２ａよりも小さくし、正極非対向部７２ｂの不可逆容量を正極対向部７２ａより小さくすることで、非水電解質二次電池の初期効率の低下を効果的に抑制できる。 The second negative electrode active material layer 722 at least partially disposed in the positive electrode non-facing portion 72 b is configured such that the mass ratio of SiO x in the contained negative electrode active material is smaller than that of the first negative electrode active material layer 721 Be done. As a negative electrode active material in the second negative electrode active material layer 722, active materials other than the above-mentioned SiO x can be used, and SiO x may be contained. As an active material other than SiO x , an active material which does not produce lithium silicate in a charge and discharge process is preferable in that the irreversible capacity is small. Among them, carbon materials are more preferable and graphite is more preferable in that the irreversible capacity is particularly small and the conductivity is also high. Using an active material having a smaller irreversible capacity than SiO x for the second negative electrode active material layer 722, the mass ratio of SiO x contained in the active material of the positive electrode non-facing portion 72b is made smaller than that of the positive electrode facing portion 72a, By making the irreversible capacity of the non-facing portion 72b smaller than that of the positive electrode facing portion 72a, it is possible to effectively suppress the decrease in the initial efficiency of the non-aqueous electrolyte secondary battery.

第１負極活物質層７２１及び第２負極活物質層７２２は、層内で活物質の組成が一定であってもよく、これが変化してもよい。負極活物質層７２全体で活物質の組成が連続的又は段階的に変化する場合でも、正極対向部７２ａがＳｉＯｘを備え、正極非対向部７２ｂの活物質が含有するＳｉＯｘの質量比率が、正極対向部７２ａよりも小さくなっていれば、初期効率の低下は抑制できる。 The composition of the active material in the first negative electrode active material layer 721 and the second negative electrode active material layer 722 may be constant or may be changed. In total negative electrode active material layer 72 even if the composition of the active material changes continuously or stepwise, with the positive electrode facing portion 72a is a SiO x, the mass ratio of SiO x in which the active material of the positive electrode non-facing portion 72b is contained in the If the size is smaller than that of the positive electrode facing portion 72a, a decrease in the initial efficiency can be suppressed.

第１負極活物質層７２１及び第２負極活物質層７２２には、前記負極活物質の他に、必要に応じて、導電剤、結着剤及びフィラー等の添加剤が含まれていてもよい。添加剤の量は、負極を高容量とする点から、各負極活物質層の総質量に対して８０質量％未満が好ましく、５０質量％以下がより好ましく、２０質量％以下がさらに好ましい。すなわち、各負極活物質層における負極活物質の量は、該各負極活物質層の総質量に対して２０質量％を超えることが好ましく、５０質量％を超えることがより好ましく、８０質量％を超えることがさらに好ましい。   In addition to the negative electrode active material, the first negative electrode active material layer 721 and the second negative electrode active material layer 722 may contain additives such as a conductive agent, a binder, and a filler, as necessary. . The amount of the additive is preferably less than 80% by mass, more preferably 50% by mass or less, and still more preferably 20% by mass or less based on the total mass of each negative electrode active material layer, from the viewpoint of increasing the capacity of the negative electrode. That is, the amount of the negative electrode active material in each negative electrode active material layer is preferably more than 20% by mass, more preferably more than 50% by mass, and 80% by mass with respect to the total mass of the respective negative electrode active material layers. It is more preferable to exceed.

導電剤としては、電池性能に悪影響を及ぼさない電子伝導性材料であれば制限はなく、例えば、カーボンブラック、アセチレンブラック、ケッチェンブラック、カーボンウイスカー、炭素繊維、金属（銅、ニッケル、アルミニウム、銀、金等）粉、金属繊維、導電性セラミックス材料等の導電性材料が挙げられる。これらの導電剤は、１種単独で使用してもよく、また２種以上を組み合わせて使用してもよい。導電剤の添加量は、各負極活物質層の総質量に対して０．１質量％〜５０質量％が好ましく、０．５質量％〜３０質量％がより好ましい。   The conductive agent is not particularly limited as long as it is an electron conductive material that does not adversely affect the battery performance, and, for example, carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber, metal (copper, nickel, aluminum, silver , Gold, etc.) conductive materials such as powders, metal fibers, and conductive ceramic materials. These conductive agents may be used alone or in combination of two or more. 0.1 mass%-50 mass% are preferable with respect to the total mass of each negative electrode active material layer, and, as for the addition amount of a conductive agent, 0.5 mass%-30 mass% are more preferable.

結着剤としては、例えば、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、フッ化ビニリデン−ヘキサフルオロプロピレン共重合体、スチレン−ブタジエンゴム（ＳＢＲ）、ポリアクリル酸又はその塩、ウレタン化合物、ポリアクリロニトリル、フッ素ゴム等が挙げられる。これらの結着剤は、１種単独で使用してもよく、また２種以上を組み合わせて使用してもよい。また、結着剤としてスチレン−ブタジエンゴムを使用する場合、増粘剤としてカルボキシメチルセルロース（ＣＭＣ）を添加することが好ましい。結着剤の添加量は、各負極活物質層の総質量に対して０．５〜３０質量％が好ましく、１〜２０質量％がより好ましい。   As the binder, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, styrene-butadiene rubber (SBR), polyacrylic acid or a salt thereof, urethane Compounds, polyacrylonitrile, fluororubber and the like can be mentioned. These binders may be used singly or in combination of two or more. Moreover, when using styrene- butadiene rubber as a binder, it is preferable to add carboxymethylcellulose (CMC) as a thickener. 0.5-30 mass% is preferable with respect to the total mass of each negative electrode active material layer, and, as for the addition amount of a binder, 1-20 mass% is more preferable.

フィラーとしては、電池性能に悪影響を及ぼさない材料であれば制限はない。通常、ポリプロピレン，ポリエチレン等のオレフィン系ポリマー、無定形シリカ、アルミナ、ゼオライト、ガラス、炭素等が用いられる。フィラーの添加量は、負極活物質層の総質量に対して３０質量％以下が好ましい。   The filler is not limited as long as the material does not adversely affect the battery performance. Usually, olefin polymers such as polypropylene and polyethylene, amorphous silica, alumina, zeolite, glass, carbon and the like are used. The amount of addition of the filler is preferably 30% by mass or less based on the total mass of the negative electrode active material layer.

負極板７に使用される負極集電体７１に制限はなく、例えば、銅、ニッケル、ステンレス鋼、ニッケルメッキ鋼、クロムメッキ鋼等の金属材料が挙げられる。これらの中でも、加工し易さとコストの点から、銅が好ましい。   The negative electrode current collector 71 used for the negative electrode plate 7 is not limited, and examples thereof include metal materials such as copper, nickel, stainless steel, nickel plated steel, and chromium plated steel. Among these, copper is preferable in terms of ease of processing and cost.

本発明で使用される負極板７は、負極活物質及び添加剤を混練して合剤とし、該合剤をＮ−メチルピロリドン，トルエン等の有機溶媒又は水に混合して、第１負極活物質層用及び第２負極活物質層用の混合液ないしペーストをそれぞれ作製し、負極集電体７１上に所定の形状となるように該各混合液ないしペーストをそれぞれ塗工し、乾燥、ロールプレス等で負極活物質層の密度及び厚みを調整することによって調製される。塗布、乾燥等の方法や条件については周知のものを採用すればよい。   The negative electrode plate 7 used in the present invention is prepared by kneading the negative electrode active material and the additive to form a mixture, and the mixture is mixed with an organic solvent such as N-methylpyrrolidone, toluene or water to obtain a first negative electrode active. A mixed solution or paste for the material layer and the second negative electrode active material layer is prepared, and each mixed solution or paste is coated on the negative electrode current collector 71 to have a predetermined shape, dried, and rolled. It is prepared by adjusting the density and thickness of the negative electrode active material layer with a press or the like. Well-known methods and conditions such as coating and drying may be adopted.

［正極板］
上述の構造を有する正極板６について、以下に詳細を説明する。 [Positive plate]
The details of the positive electrode plate 6 having the above-described structure will be described below.

正極活物質層６２には、正極活物質が含まれる。正極活物質としては、リチウムイオンを可逆的に吸蔵および放出できれば限定されず、無機化合物であってもよく、また有機化合物であってもよい。正極活物質として使用される無機化合物としては、例えば、リチウムニッケル複合酸化物（例えばＬｉｘＮｉＯ２等）、リチウムコバルト複合酸化物（例えばＬｉｘＣｏＯ２等）、リチウムニッケルコバルト複合酸化物（例えばＬｉＮｉ１−ｙＣｏｙＯ２等）、リチウムニッケルコバルトマンガン複合酸化物（例えばＬｉＮｉｘＣｏｙＭｎ１−ｘ−ｙＯ２等）、スピネル型リチウムマンガン複合酸化物（ＬｉｘＭｎ２Ｏ４等）、オリビン構造を有するリチウムリン酸化物（例えばＬｉｘＦｅＰＯ４、ＬｉｘＦｅ１−ｙＭｎｙＰＯ４、ＬｉｘＣｏＰＯ４等）等が挙げられる。また、正極活物質として使用される有機化合物としては、例えば、ポリアニリン、ポリピロール等の導電性ポリマー材料、ジスルフィド系ポリマー材料、フッ化カーボン等が挙げられる。これらの正極活物質は、１種単独で使用してもよく、また２種以上を組み合わせて使用してもよい。 The positive electrode active material layer 62 contains a positive electrode active material. The positive electrode active material is not limited as long as it can occlude and release lithium ions reversibly, and may be an inorganic compound or an organic compound. As an inorganic compound used as a positive electrode active material, for example, lithium nickel complex oxide (for example, Li x NiO 2 etc.), lithium cobalt complex oxide (for example, Li x CoO 2 etc.), lithium nickel cobalt complex oxide (for example, LiNi 1-y Co y O 2 etc.), lithium nickel cobalt manganese complex oxide (eg LiNi x Co y Mn 1-x-y O 2 etc.), spinel type lithium manganese complex oxide (Li x Mn 2 O 4 etc. And lithium phosphorus oxides having an olivine structure (for example, Li x FePO 4 , Li x Fe 1-y Mn y PO 4 , Li x CoPO 4 and the like) and the like. Moreover, as an organic compound used as a positive electrode active material, electroconductive polymer materials, such as polyaniline and polypyrrole, a disulfide type polymer material, carbon fluoride fluoride, etc. are mentioned, for example. These positive electrode active materials may be used singly or in combination of two or more.

また、正極活物質層６２には、前記正極活物質の他に、必要に応じて、導電剤、結着剤、フィラー等の添加剤が含まれていてもよい。これらの添加剤の種類及び好ましい添加量については、第１負極活物質層７２１及び第２負極活物質層７２２に配合される添加剤と同様である。   In addition to the positive electrode active material, the positive electrode active material layer 62 may contain additives such as a conductive agent, a binder, and a filler, as necessary. About the kind and preferable addition amount of these additives, it is the same as that of the additive mix | blended with the 1st negative electrode active material layer 721 and the 2nd negative electrode active material layer 722.

正極板６に使用される正極集電体６１に制限はなく、例えば、アルミニウム、タンタル、ニオブ、チタン、ハフニウム、ジルコニウム、亜鉛、タングステン、ビスマス、およびこれらの金属を含む合金等の金属材料；カーボンクロス、カーボンペーパー等の炭素質材料等が挙げられる。これらの中でも、アルミニウムが好ましい。   The positive electrode current collector 61 used for the positive electrode plate 6 is not limited, and, for example, metal materials such as aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and alloys containing these metals; carbon Examples thereof include carbonaceous materials such as cloth and carbon paper. Among these, aluminum is preferred.

本発明で使用される正極板６は、正極活物質及び添加剤を混練して合剤とし、該合剤をＮ−メチルピロリドン，トルエン等の有機溶媒又は水に混合して混合液ないしペーストを作製し、正極集電体６１上に所定の形状となるように該混合液ないしペーストを塗工し、乾燥、ロールプレス等で正極活物質層の密度及び厚みを調整することによって調製される。塗布、乾燥等の方法や条件については周知のものを採用すればよい。   In the positive electrode plate 6 used in the present invention, the positive electrode active material and the additive are kneaded to form a mixture, and the mixture is mixed with an organic solvent such as N-methylpyrrolidone, toluene or water to obtain a mixture or paste. The liquid mixture or paste is coated so as to have a predetermined shape on the positive electrode current collector 61, and the density and thickness of the positive electrode active material layer are adjusted by drying, roll pressing or the like. Well-known methods and conditions such as coating and drying may be adopted.

［非水電解質］
本実施形態に係る非水電解質二次電池に用いる非水電解質に制限はなく、一般に非水電解質二次電池への使用が提案されているものが使用可能である。非水電解質に用いる非水溶媒としては、プロピレンカーボネート、エチレンカーボネート、ブチレンカーボネート、フルオロエチレンカーボネート、クロロエチレンカーボネート、ビニレンカーボネート等の環状炭酸エステル類；γ−ブチロラクトン、γ−バレロラクトン等の環状エステル類；ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、フッ素化エチルメチルカーボネート等の鎖状カーボネート類；ギ酸メチル、酢酸メチル、酪酸メチル、フッ素化プロピオン酸メチル等の鎖状エステル類；テトラヒドロフランまたはその誘導体；１，３−ジオキサン、１，４−ジオキサン、１，２−ジメトキシエタン、１，４−ジブトキシエタン、メチルジグライム、フッ素化エーテル等のエーテル類；アセトニトリル、ベンゾニトリル等のニトリル類；ジオキソランまたはその誘導体；エチレンスルフィド、スルホラン、スルトンまたはその誘導体等の単独またはそれら２種以上の混合物等を挙げることができるが、これらに限定されるものではない。 [Non-aqueous electrolyte]
There is no restriction | limiting in the non-aqueous electrolyte used for the non-aqueous electrolyte secondary battery which concerns on this embodiment, What can generally be used for a non-aqueous electrolyte secondary battery can be used. As nonaqueous solvents used for nonaqueous electrolytes, cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, vinylene carbonate, etc .; Cyclic esters such as γ-butyrolactone and γ-valerolactone Linear carbonates such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluorinated ethyl methyl carbonate; linear esters such as methyl formate, methyl acetate, methyl butyrate, methyl fluorinated propionate; tetrahydrofuran or derivatives thereof; 1 , Ethers such as 3-dioxane, 1,4-dioxane, 1,2-dimethoxyethane, 1,4-dibutoxyethane, methyl diglyme, fluorinated ethers; acetonitrile, Nitriles such as nzonitrile, etc .; dioxolane or a derivative thereof; ethylene sulfide, sulfolane, sultone or a derivative thereof alone or a mixture of two or more thereof can be mentioned, but it is not limited thereto.

非水電解質に用いる電解質塩にも制限はなく、例えば、ＬｉＣｌＯ４，ＬｉＢＦ４，ＬｉＡｓＦ６，ＬｉＰＦ６，ＬｉＳＣＮ，ＬｉＢｒ，ＬｉＩ，Ｌｉ２ＳＯ４，Ｌｉ２Ｂ１０Ｃｌ１０，ＮａＣｌＯ４，ＮａＩ，ＮａＳＣＮ，ＮａＢｒ，ＫＣｌＯ４，ＫＳＣＮ等のリチウム（Ｌｉ）、ナトリウム（Ｎａ）またはカリウム（Ｋ）の１種を含む無機イオン塩、ＬｉＣＦ３ＳＯ３，ＬｉＮ（ＣＦ３ＳＯ２）２，ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２，ＬｉＮ（ＣＦ３ＳＯ２）（Ｃ４Ｆ９ＳＯ２），ＬｉＣ（ＣＦ３ＳＯ２）３，ＬｉＣ（Ｃ２Ｆ５ＳＯ２）３，（ＣＨ３）４ＮＢＦ４，（ＣＨ３）４ＮＢｒ，（Ｃ２Ｈ５）４ＮＣｌＯ４，（Ｃ２Ｈ５）４ＮＩ，（Ｃ３Ｈ７）４ＮＢｒ，（ｎ−Ｃ４Ｈ９）４ＮＣｌＯ４，（ｎ−Ｃ４Ｈ９）４ＮＩ，（Ｃ２Ｈ５）４Ｎ−ｍａｌｅａｔｅ，（Ｃ２Ｈ５）４Ｎ−ｂｅｎｚｏａｔｅ，（Ｃ２Ｈ５）４Ｎ−ｐｈｔｈａｌａｔｅ、ステアリルスルホン酸リチウム、オクチルスルホン酸リチウム、ドデシルベンゼンスルホン酸リチウム等の有機イオン塩等が挙げられ、これらのイオン性化合物を単独、あるいは２種類以上混合して用いることが可能である。 There is also no limitation on the electrolyte salt used for the non-aqueous electrolyte, for example, LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiSCN, LiBr, LiI, Li 2 SO 4 , Li 2 B 10 Cl 10 , NaClO 4 , NaI, Inorganic ionic salts containing lithium (Li), sodium (Na) or potassium (K) such as NaSCN, NaBr, KClO 4 , KSCN, LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C) 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2 ), LiC (CF 3 SO 2 ) 3 , LiC (C 2 F 5 SO 2 ) 3 , (CH 3 ) 4 NBF 4 , (CH 3 ) 4 NBr, (C 2 H 5 ) 4 NClO 4 , (C 2 H 5 ) 4 NI, (C 3 H 7 ) 4 NBr, (n-C) 4 H 9 ) 4 N ClO 4 , (nC 4 H 9 ) 4 NI, (C 2 H 5 ) 4 N-maleate, (C 2 H 5 ) 4 N-benzoate, (C 2 H 5 ) 4 N- Examples thereof include organic ion salts such as phthalate, lithium stearyl sulfonate, lithium octyl sulfonate, lithium dodecylbenzene sulfonate and the like, and these ionic compounds can be used alone or in combination of two or more.

さらに、ＬｉＰＦ６又はＬｉＢＦ４と、ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２のようなパーフルオロアルキル基を有するリチウム塩とを混合して用いることにより、さらに電解質の粘度を下げることができるので、低温特性をさらに高めることができ、また、自己放電を抑制することができ、より好ましい。
また、非水電解質として常温溶融塩やイオン液体を用いてもよい。 Furthermore, the viscosity of the electrolyte can be further reduced by mixing and using LiPF 6 or LiBF 4 and a lithium salt having a perfluoroalkyl group such as LiN (C 2 F 5 SO 2 ) 2 . Low temperature characteristics can be further enhanced, and self-discharge can be suppressed, which is more preferable.
Further, as the non-aqueous electrolyte, a normal temperature molten salt or an ionic liquid may be used.

非水電解質における電解質塩の濃度としては、高い電池特性を有する非水電解質二次電池を確実に得るために、０．１ｍｏｌ／Ｌ〜５ｍｏｌ／Ｌが好ましく、さらに好ましくは、０．５ｍｏｌ／Ｌ〜２．５ｍｏｌ／Ｌである。   The concentration of the electrolyte salt in the non-aqueous electrolyte is preferably 0.1 mol / L to 5 mol / L, more preferably 0.5 mol / L, in order to reliably obtain a non-aqueous electrolyte secondary battery having high battery characteristics. It is -2.5 mol / L.

さらに、本実施形態に係る非水電解質二次電池に用いる非水電解質には、前記溶質と非水溶媒の他に、必要に応じて、過充電防止剤、負極被膜形成剤、正極保護剤等の添加剤が含まれていてもよい。過充電防止剤としては、具体的には、ビフェニル、シクロヘキシルベンゼン等が挙げられる。また、負極被膜形成剤としては、具体的には、ビニレンカーボネート、ビニルエチレンカーボネート、フルオロエチレンカーボネート等が挙げられる。また、正極保護剤としては、具体的には、プロパンスルトン等が挙げられる。これらの添加剤は１種単独で用いてもよく、２種以上を混合して用いてもよい。また、非水電解質におけるこれらの添加剤の含有量については、特に制限されず、当該添加剤の種類等に応じて適宜設定すればよいが、例えば０．０１〜１５質量％、好ましくは０．１〜１０質量％、さらに好ましくは０．２〜１０質量％が挙げられる。   Furthermore, in the non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery according to the present embodiment, in addition to the solute and the non-aqueous solvent, an overcharge inhibitor, a negative electrode film forming agent, a positive electrode protective agent, etc. And additives may be included. Specific examples of the overcharge inhibitor include biphenyl and cyclohexylbenzene. Further, specific examples of the negative electrode film forming agent include vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate and the like. Further, specific examples of the positive electrode protective agent include propane sultone and the like. These additives may be used alone or in combination of two or more. Further, the content of these additives in the non-aqueous electrolyte is not particularly limited and may be appropriately set according to the type of the additive etc., but it is, for example, 0.01 to 15% by mass, preferably 0. 1-10 mass%, More preferably, 0.2-10 mass% is mentioned.

［セパレータ］
セパレータ８としては、優れた高率放電性能を示す多孔膜や不織布等を、単独あるいは併用することが好ましい。非水電解質二次電池用セパレータを構成する材料としては、例えばポリエチレン，ポリプロピレン等に代表されるポリオレフィン系樹脂、ポリエチレンテレフタレート，ポリブチレンテレフタレート等に代表されるポリエステル系樹脂、ポリフッ化ビニリデン、フッ化ビニリデン−ヘキサフルオロプロピレン共重合体、フッ化ビニリデン−パーフルオロビニルエーテル共重合体、フッ化ビニリデン−テトラフルオロエチレン共重合体、フッ化ビニリデン−トリフルオロエチレン共重合体、フッ化ビニリデン−フルオロエチレン共重合体、フッ化ビニリデン−ヘキサフルオロアセトン共重合体、フッ化ビニリデン−エチレン共重合体、フッ化ビニリデン−プロピレン共重合体、フッ化ビニリデン−トリフルオロプロピレン共重合体、フッ化ビニリデン−テトラフルオロエチレン−ヘキサフルオロプロピレン共重合体、フッ化ビニリデン−エチレン−テトラフルオロエチレン共重合体等を挙げることができる。 [Separator]
As the separator 8, it is preferable to use a porous film, a nonwoven fabric or the like exhibiting excellent high-rate discharge performance alone or in combination. Examples of materials constituting separators for non-aqueous electrolyte secondary batteries include polyolefin resins represented by polyethylene and polypropylene, polyester resins represented by polyethylene terephthalate and polybutylene terephthalate, polyvinylidene fluoride and vinylidene fluoride. -Hexafluoropropylene copolymer, vinylidene fluoride-perfluorovinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-fluoroethylene copolymer , Vinylidene fluoride-hexafluoroacetone copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-propylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinyl fluoride Den - tetrafluoroethylene - hexafluoropropylene copolymer, vinylidene fluoride - ethylene - can be mentioned tetrafluoroethylene copolymer.

セパレータ８の空孔率は強度の観点から９８体積％以下が好ましい。また、充放電特性の観点から空孔率は２０体積％以上が好ましい。   The porosity of the separator 8 is preferably 98% by volume or less from the viewpoint of strength. In addition, the porosity is preferably 20% by volume or more from the viewpoint of charge and discharge characteristics.

また、セパレータ８は、例えばアクリロニトリル、エチレンオキシド、プロピレンオキシド、メチルメタアクリレート、ビニルアセテート、ビニルピロリドン、ポリフッ化ビニリデン等のポリマーと電解質とで構成されるポリマーゲルを用いてもよい。非水電解質をゲル状態で用いると、漏液を防止する効果がある点で好ましい。   In addition, the separator 8 may use, for example, a polymer gel composed of a polymer such as acrylonitrile, ethylene oxide, propylene oxide, methyl methacrylate, vinyl acetate, vinyl pyrrolidone, polyvinylidene fluoride and the like, and an electrolyte. It is preferable to use the non-aqueous electrolyte in the gel state in view of the effect of preventing liquid leakage.

さらに、セパレータ８は、上述したような多孔膜や不織布等とポリマーゲルを併用して用いると、電解質の保液性が向上するため好ましい。即ち、ポリエチレン微孔膜の表面及び微孔壁面に厚さ数μｍ以下の親溶媒性ポリマーを被覆したフィルムを形成し、前記フィルムの微孔内に電解質を保持させることで、前記親溶媒性ポリマーがゲル化する。   Furthermore, it is preferable to use the separator 8 in combination with the above-mentioned porous film, non-woven fabric, and the like, and the polymer gel, because the liquid retention of the electrolyte is improved. That is, a film is formed by coating a surface and microporous wall surface of a polyethylene microporous membrane with a solvophilic polymer having a thickness of several μm or less, and the electrolyte is held in the pores of the film to obtain the above-mentioned solvophilic polymer Is gelled.

前記親溶媒性ポリマーとしては、ポリフッ化ビニリデンの他、エチレンオキシド基やエステル基等を有するアクリレートモノマー、エポキシモノマー、イソシアナート基を有するモノマー等が架橋したポリマー等が挙げられる。該モノマーは、電子線（ＥＢ）照射、又は、ラジカル開始剤を添加して加熱若しくは紫外線（ＵＶ）照射を行うこと等により、架橋反応を行わせることが可能である。   Examples of the lyophilic polymer include, in addition to polyvinylidene fluoride, an acrylate monomer having an ethylene oxide group or an ester group, a polymer obtained by crosslinking an epoxy monomer, a monomer having an isocyanate group, and the like. The monomer can carry out a crosslinking reaction by electron beam (EB) irradiation, or by adding a radical initiator and performing heating or ultraviolet (UV) irradiation.

［他の構成要素］
本実施形態に係る非水電解質二次電池におけるその他の電池の構成要素としては、端子、絶縁板、電池ケース等があるが、本発明の非水電解質二次電池において、これらの構成要素は従来用いられているものをそのまま用いても差し支えない。 [Other components]
Although there exist a terminal, an insulating board, a battery case etc. as a component of the other battery in the non-aqueous electrolyte secondary battery which concerns on this embodiment, in the non-aqueous electrolyte secondary battery of this invention, these components are It is acceptable to use the one used as it is.

［蓄電装置の構成］
本実施形態は、上述の非水電解質二次電池を複数個集合した蓄電装置としても実現することができる。本発明の一態様に係る蓄電装置を図７に示す。図７において、蓄電装置３０は、複数の蓄電ユニット２０を備えている。それぞれの蓄電ユニット２０は、複数の非水電解質二次電池１を備えている。前記蓄電装置３０は、電気自動車（ＥＶ）、ハイブリッド自動車（ＨＥＶ）、プラグインハイブリッド自動車（ＰＨＥＶ）等の自動車用電源として搭載することができる。 [Configuration of power storage device]
The present embodiment can also be realized as a power storage device in which a plurality of the above-described non-aqueous electrolyte secondary batteries are collected. A power storage device according to one embodiment of the present invention is illustrated in FIG. In FIG. 7, power storage device 30 includes a plurality of power storage units 20. Each storage unit 20 includes a plurality of non-aqueous electrolyte secondary batteries 1. The power storage device 30 can be mounted as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV).

以下、実施例により、本実施形態に係る非水電解質二次電池の負極板の作製手順を具体的に説明する。   Hereinafter, the procedure for producing the negative electrode plate of the non-aqueous electrolyte secondary battery according to the present embodiment will be specifically described by way of examples.

［実施例１］
（第１負極活物質層の形成）
ＳｉＯｘと黒鉛を２０．４：７９．６の質量比率で含有する負極活物質、導電助剤としてカーボンブラック、結着剤としてスチレン−ブタジエンゴム、及び増粘剤としてカルボキシメチルセルロースを用い、水を分散媒とする第１負極活物質層用ペーストを作製する。該ペースト中の前記負極活物質、前記導電助剤、前記結着剤、及び前記増粘剤の質量比率は、９４．８：１．９：２．１：１．２である。この第１負極活物質層用ペーストを、長尺シート形状の負極集電体である厚さ８μｍの銅箔の両面に対して、幅方向の両端部を除く中央部に、両面の塗布形状が同じで、かつ幅が正極の正極活物質層と同じになるように塗布し、１００℃で乾燥することで、第１負極活物質層を形成する。 Example 1
(Formation of first negative electrode active material layer)
A negative electrode active material containing SiO x and graphite in a mass ratio of 20.4: 79.6, carbon black as a conductive additive, styrene-butadiene rubber as a binder, and carboxymethyl cellulose as a thickener, water A paste for a first negative electrode active material layer to be a dispersion medium is prepared. The mass ratio of the negative electrode active material, the conductive auxiliary agent, the binder, and the thickener in the paste is 94.8: 1.9: 2.1: 1.2. The first negative electrode active material layer paste is applied on both sides of the copper foil having a thickness of 8 μm, which is a long sheet-shaped negative electrode current collector, in the central portion excluding both end portions in the width direction. The first negative electrode active material layer is formed by applying the same and having the same width as the positive electrode active material layer of the positive electrode, and drying at 100 ° C.

（第２負極活物質層の形成）
負極活物質として黒鉛、結着剤としてスチレン−ブタジエンゴム、及び増粘剤としてカルボキシメチルセルロースを用い、水を分散媒とする第２負極活物質層用ペーストを作製した。該ペースト中の前記負極活物質、前記結着剤、及び前記増粘剤の質量比率は９６．７：２．１：１．２である。この第２負極活物質層用ペーストを、第１負極活物質層が形成された前記銅箔の両面に対して、第１負極活物質層を形成しなかった幅方向の両端部の一部に、両面の塗布形状が同じで、かつ第１負極活物質層と第２負極活物質層とが相互に接触するように塗布し、１００℃で乾燥することで第２活物質層を形成し、実施例１に係る負極板を得る。
このとき、長尺シート形状の負極集電体上の、幅方向に第１負極活物質層及び第２負極活物質層を共に形成した単位長さの領域における、第１負極活物質層に対する第２負極活物質層の面積比は、０．０９である。 (Formation of second negative electrode active material layer)
Using a graphite as a negative electrode active material, a styrene-butadiene rubber as a binder, and carboxymethyl cellulose as a thickener, a paste for a second negative electrode active material layer was prepared using water as a dispersion medium. The mass ratio of the negative electrode active material, the binder, and the thickener in the paste is 96.7: 2.1: 1.2. The paste for the second negative electrode active material layer was applied to part of both end portions in the width direction in which the first negative electrode active material layer was not formed on both sides of the copper foil on which the first negative electrode active material layer was formed. The second active material layer is formed by applying the same shape of both sides and applying the first negative electrode active material layer and the second negative electrode active material layer in contact with each other, and drying at 100 ° C. A negative electrode plate according to Example 1 is obtained.
At this time, the first negative electrode active material layer is formed on the long sheet-shaped negative electrode current collector in a region of a unit length in which the first negative electrode active material layer and the second negative electrode active material layer are both formed in the width direction. The area ratio of the two negative electrode active material layers is 0.09.

（正極板の作製）
９０質量％のＬｉＮｉ０．３３３Ｃｏ０．３３３Ｍｎ０．３３３Ｏ２、５質量％のＰＶｄＦ及び５質量％のアセチレンブラックを含む混合物に、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を適量加えて正極活物質形成用ペーストを作製する。
厚さ１５μｍのアルミニウム箔製の正極集電体の両面に、ダイヘッドコータを用いて、前記正極活物質形成用ペーストを、前記負極板上の第１負極活物質層と同形状となるように塗布する。
その後、乾燥処理によってＮＭＰを揮散させた後に、プレス機にて圧延することにより正極活物質層の厚さを調整し、実施例１に係る正極板を作製する。 (Production of positive plate)
An appropriate amount of N-methyl-2-pyrrolidone (NMP) is added to a mixture containing 90% by mass of LiNi 0.333 Co 0.333 Mn 0.333 O 2 , 5% by mass of PVdF and 5% by mass of acetylene black A paste for forming a positive electrode active material is prepared.
Using a die head coater, apply the paste for positive electrode active material formation on both sides of a 15 μm thick positive electrode current collector made of aluminum foil so as to have the same shape as the first negative electrode active material layer on the negative electrode plate. Do.
Thereafter, NMP is volatilized by drying treatment, and the thickness of the positive electrode active material layer is adjusted by rolling with a press, whereby the positive electrode plate according to Example 1 is produced.

（非水電解質二次電池の作製）
非水電解質として、フルオロエチレンカーボネート（ＦＥＣ）：エチルメチルカーボネート（ＥＭＣ）＝１：９（体積比）の混合溶媒にＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を用意する。セパレータとして、ポリプロピレン製の微孔膜を用意する。また、外装体として、アルミニウム製の角形電槽缶を用意する。
負極板上の第１負極活物質層が正極板上の正極活物質層と対向するように、前記負極板及び正極板をセパレータを介して配置し、図４に示す態様の電極体を作製した。その後、前記外装体に前記電極体を収納し、正極及び負極を２つの外部端子それぞれに電気的に接続させた後に、ケース本体に蓋板を取り付けた。さらに、前記非水電解質を外装体の蓋板に形成された注液孔から外装体内に注液後、注液孔を封止して、実施例１に係る非水電解質二次電池を作製する。 (Fabrication of non-aqueous electrolyte secondary battery)
As a non-aqueous electrolyte, a solution in which LiPF 6 is dissolved in a mixed solvent of fluoroethylene carbonate (FEC): ethyl methyl carbonate (EMC) = 1: 9 (volume ratio) to 1 mol / L is prepared. A microporous polypropylene membrane is prepared as a separator. In addition, a rectangular battery case made of aluminum is prepared as an exterior body.
The said negative electrode plate and the positive electrode plate were arrange | positioned through the separator so that the 1st negative electrode active material layer on a negative electrode plate may face the positive electrode active material layer on a positive electrode plate, and the electrode body of the aspect shown in FIG. 4 was produced. . Thereafter, the electrode body was housed in the outer package, and the positive electrode and the negative electrode were electrically connected to each of the two external terminals, and then a cover plate was attached to the case main body. Furthermore, after injecting the non-aqueous electrolyte into the outer body from the liquid injection hole formed in the lid plate of the outer body, the liquid injection hole is sealed, and the non-aqueous electrolyte secondary battery according to Example 1 is manufactured. .

［実施例２］
（第１負極活物質層の形成）
ＳｉＯｘと黒鉛を６８．２：３１．８の質量比率で含有する負極活物質、導電助剤としてカーボンブラック、結着剤としてポリアクリル酸ナトリウムを用い、水を分散媒とする第１負極活物質層用ペーストを作製する。該ペースト中の前記負極活物質、前記導電助剤、及び前記結着剤の質量比率は８８：２：１０である。この第１負極活物質層用ペーストを、実施例１と同様の方法で集電体に塗布及び乾燥することで、第１負極活物質層を形成する。 Example 2
(Formation of first negative electrode active material layer)
A negative electrode active material containing SiO x and graphite at a mass ratio of 68.2: 31.8, carbon black as a conductive additive, sodium polyacrylate as a binder, and first negative electrode active using water as a dispersion medium Prepare paste for material layer. The mass ratio of the negative electrode active material to the conductive auxiliary agent to the binder in the paste is 88: 2: 10. The first negative electrode active material layer paste is applied to a current collector in the same manner as in Example 1 and dried to form a first negative electrode active material layer.

（第２負極活物質層の形成）
負極活物質として難黒鉛化性炭素（ハードカーボン）、結着剤としてポリフッ化ビニリデンを用い、Ｎ−メチルピロリドンを分散媒とする第２負極活物質層用ペーストを作製する。該ペースト中の前記負極活物質と結着剤との質量比率は９５：５である。この第２負極活物質層用ペーストを、第１負極活物質層が形成された前記銅箔の両面に対して、第１負極活物質層を形成しなかった幅方向の両端部の一部に、両面の塗布形状が同じで、かつ第１負極活物質層と第２負極活物質層とが相互に接触するように塗布し、１２０℃で乾燥することで第２活物質層を形成し、実施例２に係る負極板を得る。
このとき、長尺シート形状の負極集電体上の、幅方向に第１負極活物質層及び第２負極活物質層を共に形成した単位長さの領域における、第１負極活物質層に対する第２負極活物質層の面積比は、０．０９である。 (Formation of second negative electrode active material layer)
A non-graphitizable carbon (hard carbon) as a negative electrode active material, polyvinylidene fluoride as a binder, and a paste for a second negative electrode active material layer using N-methyl pyrrolidone as a dispersion medium are prepared. The mass ratio of the negative electrode active material to the binder in the paste is 95: 5. The paste for the second negative electrode active material layer was applied to part of both end portions in the width direction in which the first negative electrode active material layer was not formed on both sides of the copper foil on which the first negative electrode active material layer was formed. The second active material layer is formed by applying the same coating shape on both sides and in such a manner that the first negative electrode active material layer and the second negative electrode active material layer are in contact with each other, and drying at 120 ° C. A negative electrode plate according to Example 2 is obtained.
At this time, the first negative electrode active material layer is formed on the long sheet-shaped negative electrode current collector in a region of a unit length in which the first negative electrode active material layer and the second negative electrode active material layer are both formed in the width direction. The area ratio of the two negative electrode active material layers is 0.09.

（正極板の作製）
実施例１と同様の方法で、実施例２に係る正極板を作製する。 (Production of positive plate)
In the same manner as in Example 1, a positive electrode plate according to Example 2 is produced.

（非水電解質二次電池の作製）
実施例１と同様の方法で、実施例２に係る非水電解質二次電池を作製する。 (Fabrication of non-aqueous electrolyte secondary battery)
In the same manner as in Example 1, a non-aqueous electrolyte secondary battery according to Example 2 is produced.

本発明の一側面に係る非水電解質二次電池は、高容量で初期効率が高いため、ハイブリッド自動車用、電気自動車用の非水電解質二次電池として有用である。   The non-aqueous electrolyte secondary battery according to one aspect of the present invention is useful as a non-aqueous electrolyte secondary battery for hybrid vehicles and electric vehicles because of its high capacity and high initial efficiency.

１ 非水電解質二次電池（リチウム二次電池）
２ 電極群
３ 電池容器
４ 正極端子
４’ 正極リード
５ 負極端子
５’ 負極リード
２０ 蓄電ユニット
３０ 蓄電装置
６ 正極板
６１ 正極集電体
６２ 正極活物質層
７ 負極板
７１ 負極集電体
７２ 負極活物質層
７２ａ 正極対向部
７２ｂ 正極非対向部
７２１ 第１負極活物質層
７２２ 第２負極活物質層
８ セパレータ

1 Non-aqueous electrolyte secondary battery (lithium secondary battery)
DESCRIPTION OF SYMBOLS 2 electrode group 3 battery container 4 positive electrode terminal 4 'positive electrode lead 5 negative electrode terminal 5' negative electrode lead 20 electrical storage unit 30 electrical storage device 6 positive electrode plate 61 positive electrode collector 62 positive electrode active material layer 7 negative electrode plate 71 negative electrode collector 72 negative electrode active Substance layer 72a Positive electrode facing portion 72b Positive electrode non-facing portion 721 First negative electrode active material layer 722 Second negative electrode active material layer 8 Separator

Claims (3)

正極集電体上に正極活物質層を有する正極板と、負極集電体上に負極活物質層を有する負極板とを備える非水電解質二次電池であって、
前記負極活物質層が、
前記正極活物質層に対向する領域である正極対向部と、前記正極活物質層に対向していない領域である正極非対向部とを備え、
前記正極対向部に配置された第１負極活物質層と、前記正極非対向部に少なくとも一部が配置された第２負極活物質層とを相互に接触した状態で含み、
前記正極活物質層に対向する領域が備える負極活物質層は、ＳｉＯｘを備え、
前記正極活物質層に対向していない領域が備える負極活物質層は、活物質層の活物質が含有するＳｉＯｘの質量比率が、前記正極活物質層に対向する領域が備える負極活物質層よりも小さい、
非水電解質二次電池。 A non-aqueous electrolyte secondary battery comprising a positive electrode plate having a positive electrode active material layer on a positive electrode current collector, and a negative electrode plate having a negative electrode active material layer on a negative electrode current collector,
The negative electrode active material layer is
A positive electrode facing portion which is a region facing the positive electrode active material layer, and a positive electrode non-facing portion which is a region not facing the positive electrode active material layer,
The first negative electrode active material layer disposed in the positive electrode facing portion and the second negative electrode active material layer in which at least a portion is disposed in the positive electrode non-facing portion are included in a mutually contacting state,
The negative electrode active material layer provided in the region facing the positive electrode active material layer comprises SiO x ,
The negative electrode active material layer provided in the region not facing the positive electrode active material layer is a negative electrode active material layer provided in the region where the mass ratio of SiO x contained in the active material of the active material layer faces the positive electrode active material layer Less than
Nonaqueous electrolyte secondary battery. 前記第２負極活物質層が、前記正極対向部にも配置された、請求項１に記載の非水電解質二次電池。   The nonaqueous electrolyte secondary battery according to claim 1, wherein the second negative electrode active material layer is also disposed in the positive electrode facing portion. 前記第２活物質層が、黒鉛、難黒鉛化性炭素及び易黒鉛化性炭素から選ばれる少なくとも１つを備える、請求項１又は２に記載の非水電解質二次電池。
The non-aqueous electrolyte secondary battery according to claim 1, wherein the second active material layer comprises at least one selected from graphite, non-graphitizable carbon and graphitizable carbon.
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