WO2015152095A1 - Nonaqueous-electrolyte secondary battery - Google Patents

Abstract

This invention provides a nonaqueous-electrolyte secondary battery that, while exhibiting excellent cycle characteristics due to the use of a carbonaceous material that exhibits little expansion and contraction during charging and discharging, exhibits both the low internal resistance and the charging-curve shape with a large sloped region that are in demand for HEV applications and the like, resulting in excellent input characteristics. Said nonaqueous-electrolyte secondary battery is provided with the following: a positive electrode containing a positive-electrode active material that comprises a lithium-containing transition-metal composite oxide; a negative electrode containing a negative-electrode active material that contains a carbonaceous material; and a nonaqueous electrolyte. This nonaqueous-electrolyte secondary battery has a positive-electrode capacity (the capacity with metallic lithium used as the other electrode) of at most 3.0 mAh/cm²; the true density of the carbonaceous material, as determined using a butanol method, is between 1.70 and 2.20 g/cm³, inclusive; and the ratio (A/B) of the positive-electrode capacity (A) to the negative-electrode capacity (B) is between 0.5 and 0.9, inclusive.

Description

非水電解質二次電池Nonaqueous electrolyte secondary battery

　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.

　近年、環境問題への関心の高まりから、エネルギー密度が高く、出力特性の優れた大型のリチウムイオン二次電池の電気自動車への搭載が検討されている。携帯電話やノートパソコンといった小型携帯機器用途では、体積当たりの容量が重要となるため、密度の大きい黒鉛質材料が主に負極活物質として利用されてきた。しかし、車載用リチウムイオン二次電池においては大型で且つ高価であることから途中での交換が困難である。そのため、自動車と同じ耐久性が必要であり、例えば１０年以上の寿命性能の実現（高耐久性）が求められる。また、限られた車両空間への搭載が求められることから単位体積当たりの電池特性も重視される。 In recent years, due to increasing interest in environmental issues, the installation of large lithium ion secondary batteries with high energy density and excellent output characteristics in electric vehicles is being studied. In small portable devices such as mobile phones and notebook computers, capacity per volume is important, and thus a graphite material having a high density has been mainly used as a negative electrode active material. However, in-vehicle lithium ion secondary batteries are large and expensive, and are difficult to replace in the middle. For this reason, the same durability as that of an automobile is required, and for example, realization of a life performance of 10 years or more (high durability) is required. In addition, since it is required to be mounted in a limited vehicle space, the battery characteristics per unit volume are also emphasized.

　また、電池の使用形態についても、小型携帯機器のような満充電と完全放電を繰り返す使い方でなく、大電流での充電と放電を繰り返すという使われ方がなされる。このような形態においては、入力特性と出力特性のバランスが取れた領域、すなわち満充電を１００％とした場合に半分の５０％前後の充電領域に電池を保ちつつ入力と出力を繰り返すという使用形態を取ることが好ましい。このような使用形態を想定した場合、従来の小型携帯機器用途の電池のように使用条件下での容量変化に対してほぼ一定の電位を示す正負極を組み合わせるのではなく、ＨＥＶ用途で使用される電池では、使用条件下での容量変化に対して負極の電位変化が大きくなるように電池を設計することによって入力特性の向上を図ることができる。 Also, the usage of the battery is not to repeat full charge and complete discharge as in a small portable device, but to repeatedly charge and discharge with a large current. In such a configuration, the input and output are repeated while keeping the battery in a region where the input characteristics and the output characteristics are balanced, that is, when the full charge is 100%, which is about 50% of the charge range. It is preferable to take. Assuming this type of usage, it is used in HEV applications, rather than combining positive and negative electrodes that exhibit a substantially constant potential with respect to capacity changes under usage conditions, as in conventional batteries for small portable devices. In such a battery, the input characteristics can be improved by designing the battery so that the change in potential of the negative electrode becomes larger with respect to the change in capacity under use conditions.

　例えば、小型携帯機器電源では、放電状態から１～２時間で満充電できるような、０．５～１時間率充電の充電負荷に対応するものが求められる。一方、ハイブリッド自動車（ＨＥＶ）用電源では、ブレーキ時のエネルギー回生を行うことを考慮すると３～１０時間率程度の大電流で充電できるものが求められる。また、放電についてもアクセルを踏み込む時間を考慮すれば同程度の大電流で放電できることが必要とされるなど、小型携帯向けのリチウムイオン二次電池と比較して圧倒的に優れた急速な充放電（入出力）特性が求められている。
　このように、ＨＥＶ用途で用いられる電池は、入出力特性、特に充電に相当する入力特性が重視され、充電曲線の傾斜する領域における充電容量が大きいことが重要である。
　入力特性を向上させるために、広い領域で充電曲線が傾斜をする形状を示す炭素質材料を負極活物質に使用することが好ましい。具体的には、負極材料として容量に対して電位変化の大きな活物質である難黒鉛化性炭素や易黒鉛化性炭素を選択することが提案されている。 For example, a power supply for a small portable device is required that can handle a charging load of 0.5 to 1 hour rate charging that can be fully charged in 1 to 2 hours from a discharged state. On the other hand, a power source for a hybrid vehicle (HEV) is required that can be charged with a large current of about 3 to 10 hours in consideration of energy regeneration during braking. In addition, with regard to discharging, it is necessary to be able to discharge with the same large current if considering the time to depress the accelerator. Rapid charging and discharging, which is overwhelmingly superior to lithium-ion secondary batteries for small mobile phones. (Input / output) characteristics are required.
Thus, batteries used in HEV applications place importance on input / output characteristics, particularly input characteristics corresponding to charging, and it is important that the charging capacity in a region where the charging curve is inclined is large.
In order to improve the input characteristics, it is preferable to use, as the negative electrode active material, a carbonaceous material having a shape in which the charging curve is inclined in a wide region. Specifically, it has been proposed to select non-graphitizable carbon or graphitizable carbon which is an active material having a large potential change with respect to the capacity as the negative electrode material.

　また、車載用二次電池には良好な耐久性やサイクル特性が求められることから、耐久性やサイクル特性の改善に関して、例えば、特許文献１、２は、低結晶性炭素材料を用いて、サイクル特性や長期耐久性を向上させたものが提案されているが、電極抵抗の低減を実現するものではなく、入出力特性の改善効果が十分でない。また、特許文献１、２には、平均粒径１０μｍ以上の炭素材料が例示されているが、平均粒径１０μｍ以上程度の粒子では負極を十分に薄塗りすることができず、入出力特性の向上は得られない。 In addition, since favorable durability and cycle characteristics are required for in-vehicle secondary batteries, for example, Patent Documents 1 and 2 describe a cycle using a low crystalline carbon material for improving durability and cycle characteristics. Although the thing which improved the characteristic and long-term durability is proposed, it does not implement | achieve reduction of electrode resistance, but the improvement effect of an input-output characteristic is not enough. Patent Documents 1 and 2 exemplify carbon materials having an average particle diameter of 10 μm or more. However, the negative electrode cannot be sufficiently thinly coated with particles having an average particle diameter of about 10 μm or more. There is no improvement.

特許４９５１８２５号公報Japanese Patent No. 4951825 特許４９６１６４９号公報Japanese Patent No. 4961649

　本発明の目的は、単位体積当たりの大きな容量を実現させながら、ＨＥＶ用途等で求められる傾斜領域の大きい充電曲線形状と低い内部抵抗を両立させることで、入力特性に優れた非水電解質二次電池を提供することにある。 The object of the present invention is to achieve a large capacity per unit volume, while satisfying both a charging curve shape having a large slope region required for HEV applications and a low internal resistance, thereby providing a non-aqueous electrolyte secondary having excellent input characteristics. To provide a battery.

　本発明者らは、リチウムを含む遷移金属複合酸化物からなる正極活物質を含む正極と、炭素質材料を含む負極活物質を含む負極と、非水電解質とを備える非水電解質二次電池において、正極容量が３．０ｍＡｈ／ｃｍ^２以下（対極をＬｉ金属としたときの容量）であり、ブタノール法により求めた前記炭素質材料の真密度が１．７０～２．２０ｇ／ｃｍ^３であり、対向する正極容量Ａと負極容量Ｂの比（Ａ／Ｂ）が０．５～０．９であるものにおいて、単位体積当たりの大きな容量を実現させながら、傾斜領域の大きい充電曲線形状と低い内部抵抗を両立させた入力特性に優れる電池が提供されることを見出し、本発明を完成するに至った。具体的に、本発明は以下のようなものを提供する。 In a nonaqueous electrolyte secondary battery comprising a positive electrode including a positive electrode active material composed of a transition metal composite oxide containing lithium, a negative electrode including a negative electrode active material including a carbonaceous material, and a nonaqueous electrolyte. The positive electrode capacity is 3.0 mAh / cm ² or less (capacity when the counter electrode is Li metal), and the true density of the carbonaceous material determined by the butanol method is 1.70 to 2.20 g / cm ³ . In the case where the ratio (A / B) of the positive electrode capacity A and the negative electrode capacity B facing each other is 0.5 to 0.9, the charge curve shape having a large slope region and a low charge curve shape is realized while realizing a large capacity per unit volume. The present inventors have found that a battery excellent in input characteristics that achieves both internal resistance is provided, and has completed the present invention. Specifically, the present invention provides the following.

　（１）リチウムを含む遷移金属複合酸化物からなる正極活物質を含む正極と、炭素質材料を含む負極活物質を含む負極と、非水電解質とを備える非水電解質二次電池において、正極容量が３．０ｍＡｈ／ｃｍ^２以下（対極をＬｉ金属としたときの容量）であり、ブタノール法により求めた前記炭素質材料の真密度が１．７０～２．２０ｇ／ｃｍ^３であり、対向する正極容量Ａと負極容量Ｂの比（Ａ／Ｂ）が０．５～０．９であることを特徴とする非水電解質二次電池である。 (1) In a nonaqueous electrolyte secondary battery comprising a positive electrode including a positive electrode active material comprising a transition metal composite oxide containing lithium, a negative electrode including a negative electrode active material including a carbonaceous material, and a nonaqueous electrolyte, the positive electrode capacity Is 3.0 mAh / cm ² or less (capacity when the counter electrode is Li metal), and the true density of the carbonaceous material determined by the butanol method is 1.70 to 2.20 g / cm ³ , facing each other. The nonaqueous electrolyte secondary battery is characterized in that the ratio (A / B) of the positive electrode capacity A to the negative electrode capacity B is 0.5 to 0.9.

　（２）前記負極における炭素質材料の、Ｘ線回折測定により求められる００２面の平均層面間隔（ｄ_００２）が０．３４２ｎｍ～０．３７５ｎｍであることを特徴とする上記（１）に記載の非水電解質二次電池である。 (2) The carbonaceous material in the negative electrode has an average layer surface spacing (d ₀₀₂ ) of 002 planes determined by X-ray diffraction measurement of 0.342 nm to 0.375 nm, as described in (1) above It is a non-aqueous electrolyte secondary battery.

　（３）前記負極における負極活物質層の厚みが４５μｍ以下であることを特徴とする上記（１）または（２）に記載の非水電解質二次電池である。 (3) The nonaqueous electrolyte secondary battery according to (1) or (2) above, wherein the thickness of the negative electrode active material layer in the negative electrode is 45 μm or less.

　（４）前記炭素質材料は、平均粒子径（Ｄｖ_５０）が４．５μｍ以下であることを特徴とする上記（３）に記載の非水電解質二次電池である。 (4) The non-aqueous electrolyte secondary battery according to (3), wherein the carbonaceous material has an average particle diameter (Dv ₅₀ ) of 4.5 μm or less.

　本発明によれば、リチウムを含む遷移金属複合酸化物からなる正極活物質を含む正極と、炭素質材料を含む負極活物質を含む負極と、非水電解質とを備える非水電解質二次電池において、正極容量が３．０ｍＡｈ／ｃｍ^２以下（対極をＬｉ金属としたときの容量）であり、ブタノール法により求めた前記炭素質材料の真密度が１．７０～２．２０ｇ／ｃｍ^３であり、対向する正極容量Ａと負極容量Ｂの比（Ａ／Ｂ）が０．５～０．９であることにより、優れたサイクル特性を実現させながら、傾斜領域の大きい充電曲線形状と低い内部抵抗を両立させた入力特性に優れる電池が提供される。
　傾斜領域を大きくすることは、充電中のリチウムの析出を抑制し、充放電サイクル特性の向上に寄与することに加えて、より高負荷での充電を可能にする。また、本発明における電池は、負極活物質層の厚みが従来の負極よりも薄く、負極厚み方向の電気抵抗が低いため、電池の内部抵抗を低減させて高入出力の電池の提供を可能にする。 According to the present invention, in a nonaqueous electrolyte secondary battery comprising a positive electrode including a positive electrode active material made of a transition metal composite oxide containing lithium, a negative electrode including a negative electrode active material including a carbonaceous material, and a nonaqueous electrolyte. The positive electrode capacity is 3.0 mAh / cm ² or less (capacity when the counter electrode is Li metal), and the true density of the carbonaceous material determined by the butanol method is 1.70 to 2.20 g / cm ³ . The ratio between the positive electrode capacity A and the negative electrode capacity B (A / B) facing each other is 0.5 to 0.9, so that an excellent cycle characteristic is realized and a charging curve shape having a large slope region and a low internal resistance are achieved. A battery excellent in input characteristics that achieves both of the above is provided.
Increasing the slope region suppresses lithium deposition during charging, contributes to improvement of charge / discharge cycle characteristics, and enables charging at a higher load. In addition, since the battery according to the present invention has a negative electrode active material layer that is thinner than a conventional negative electrode and has a lower electrical resistance in the negative electrode thickness direction, the internal resistance of the battery can be reduced and a high input / output battery can be provided. To do.

実施例で用いられた入出力電流パルスを示す図である。It is a figure which shows the input-output current pulse used in the Example.

　以下、本発明の実施形態について説明する。 Hereinafter, embodiments of the present invention will be described.

　本発明の非水電解質二次電池は、リチウムを含む遷移金属複合酸化物からなる正極活物質を含む正極と、炭素質材料を含む負極活物質を含む負極と、非水電解質とを備える非水電解質二次電池において、正極容量が３．０ｍＡｈ／ｃｍ^２以下（対極をＬｉ金属としたときの容量）であり、ブタノール法により求めた前記炭素質材料の真密度が１．７０～２．２０ｇ／ｃｍ^３であり、対向する正極容量Ａと負極容量Ｂの比（Ａ／Ｂ）が０．５～０．９であることが好ましい。 A non-aqueous electrolyte secondary battery of the present invention includes a positive electrode including a positive electrode active material made of a transition metal composite oxide containing lithium, a negative electrode including a negative electrode active material including a carbonaceous material, and a non-aqueous electrolyte. In the electrolyte secondary battery, the positive electrode capacity is 3.0 mAh / cm ² or less (capacity when the counter electrode is Li metal), and the true density of the carbonaceous material determined by the butanol method is 1.70 to 2.20 g. / Cm ³ , and the ratio (A / B) of the positive electrode capacity A and the negative electrode capacity B facing each other is preferably 0.5 to 0.9.

　正極容量とは、正極電極における単位面積当たりの放電容量を意味し、二次電池の入出力に必要な充放電容量を実現するために設定される。その一方で、負極は、充電時にリチウムイオンを吸蔵するので、過剰なリチウムがリチウム金属として析出しないように正極容量の増加に応じて負極容量を増加させる必要がある。しかし、負極容量の増加によって負極の電極厚みが大きくなるのでリチウムの拡散距離が長くなり、電気抵抗が増大することから、入出力特性が低下する。また、充放電の繰り返しによる膨張収縮の影響が大きくなり、容量維持率の低下を招くことがある。そのため、正極容量は、適正範囲で一定以下にする必要があり、３．０ｍＡｈ／ｃｍ^２以下が好ましい。より好ましくは、２．７ｍＡｈ／ｃｍ^２以下である。また、ＨＥＶ等の航続距離に応じて必要とする容量を適宜設定できるから、０．８ｍＡｈ／ｃｍ^２以上にしてもよい。好ましくは、１ｍＡｈ／ｃｍ^２以上である。 The positive electrode capacity means a discharge capacity per unit area in the positive electrode, and is set to realize a charge / discharge capacity necessary for input / output of the secondary battery. On the other hand, since the negative electrode occludes lithium ions during charging, it is necessary to increase the negative electrode capacity in accordance with the increase in the positive electrode capacity so that excessive lithium does not precipitate as lithium metal. However, since the electrode thickness of the negative electrode increases as the negative electrode capacity increases, the diffusion distance of lithium becomes longer and the electrical resistance increases, so that the input / output characteristics are degraded. In addition, the influence of expansion and contraction due to repeated charging and discharging is increased, which may lead to a decrease in capacity retention rate. Therefore, the positive electrode capacity needs to be constant or less within an appropriate range, and is preferably 3.0 mAh / cm ² or less. More preferably, it is 2.7 mAh / cm ² or less. Moreover, since the required capacity can be set as appropriate according to the cruising distance such as HEV, it may be set to 0.8 mAh / cm ² or more. Preferably, it is 1 mAh / cm ² or more.

　本発明の非水電解質二次電池は、ブタノール法により求めた前記炭素質材料の真密度が１．７０～２．２０ｇ／ｃｍ^３であり、前記正極容量Ａと前記負極容量Ｂの比（Ａ／Ｂ）が０．５～０．９であることが好ましい。
　真密度が１．７０～２．２０ｇ／ｃｍ^３である炭素質材料としては、非黒鉛性材料の易黒鉛化性炭素が代表的である。この非黒鉛質材料は、放電過程を通して電位が緩やかに変化する傾斜領域を有するので、ＨＥＶ用途で重視される使用形態に適している。真密度が２．２０ｇ／ｃｍ^３を超えると、放電中に電位が緩やかに傾斜する領域が短くなり入出力特性が確保できなくなる。また、１．７０ｇ／ｃｍ^３を下回ると、材料の真密度が低くなり単位体積当たりの容量を確保する上で好ましくない。また、炭素材料の吸湿性が高くなると共に酸化されて負極の抵抗が上昇するため好ましくない。 In the nonaqueous electrolyte secondary battery of the present invention, the true density of the carbonaceous material obtained by the butanol method is 1.70 to 2.20 g / cm ³ , and the ratio of the positive electrode capacity A to the negative electrode capacity B (A / B) is preferably 0.5 to 0.9.
The carbonaceous material having a true density of 1.70 to 2.20 g / cm ³ is typically non-graphitizable carbon. Since this non-graphitic material has an inclined region in which the potential changes gradually throughout the discharge process, it is suitable for a usage pattern that is important in HEV applications. When the true density exceeds 2.20 g / cm ³ , the region where the potential gently slopes during discharge becomes short, and the input / output characteristics cannot be secured. On the other hand, if it is less than 1.70 g / cm ³ , the true density of the material becomes low, which is not preferable for securing the capacity per unit volume. Moreover, since the hygroscopicity of a carbon material becomes high and it is oxidized and the resistance of a negative electrode increases, it is not preferable.

　正極容量Ａと負極容量Ｂの比（Ａ／Ｂ）は、０．５未満であると、電池容量の低下が大きく実用的でない。一方、０．９を超えると、負極の活物質層厚みが相対的に大きくなり、電気抵抗の増大を招くことになる。また、金属リチウムが析出するまでの負極容量の余裕が小さくなるため、充放電中の電池内の副反応が積み重なって、サイクル特性の劣化や保存性の劣化を招く。そのため、この比（Ａ／Ｂ）は、０．５～０．９が好ましい。 When the ratio (A / B) between the positive electrode capacity A and the negative electrode capacity B is less than 0.5, the battery capacity is greatly reduced and is not practical. On the other hand, if it exceeds 0.9, the thickness of the active material layer of the negative electrode becomes relatively large, leading to an increase in electrical resistance. In addition, since the capacity of the negative electrode capacity until metal lithium is deposited is reduced, side reactions in the battery during charging and discharging accumulate, leading to deterioration of cycle characteristics and storage stability. Therefore, this ratio (A / B) is preferably 0.5 to 0.9.

　本発明の非水電解質二次電池は、負極電極における負極活物質層の厚みが４５μｍ以下であることが好ましい。この厚みは、負極電極の集電体の両面に負極活物質層が存在する場合には、負極から集電体の厚みを差し引いた厚みの半分に相当し、また、集電体の片面にのみ負極活物質層が存在する場合には、負極から集電体の厚みを差し引いた厚みに相当する。負極活物質層の厚みが過大であると、入出力特性が低下し、容量維持率が低下するので、負極活物質層の厚みは、片面当たりで４５μｍ以下が好ましく、より好ましくは４０μｍ以下である。 In the nonaqueous electrolyte secondary battery of the present invention, the thickness of the negative electrode active material layer in the negative electrode is preferably 45 μm or less. This thickness corresponds to half the thickness obtained by subtracting the thickness of the current collector from the negative electrode when there are negative electrode active material layers on both sides of the current collector of the negative electrode, and only on one side of the current collector. When the negative electrode active material layer is present, this corresponds to a thickness obtained by subtracting the thickness of the current collector from the negative electrode. If the thickness of the negative electrode active material layer is excessive, the input / output characteristics are lowered and the capacity retention rate is lowered. Therefore, the thickness of the negative electrode active material layer is preferably 45 μm or less per side, more preferably 40 μm or less. .

　本発明の非水電解質二次電池は、平均粒子径（Ｄｖ_５０、累積容積が５０％となる粒子径）が６μｍ以下の炭素質材料からなる負極活物質を有することが好ましい。前記炭素質物質の平均粒子径は、過大であると大きな粒子が増加するため電極を薄く塗工することが困難になり、さらに粒子内でのリチウムの拡散距離が増加するため急速な充放電が困難となり、入出力特性を低下させる。そのため、平均粒子径は、４．５μｍ以下が好ましく、より好ましくは４μｍ以下である。なお、平均粒子径が過小であると、微粉の割合が多くなり不可逆容量の増加を招くので、１μｍ以上にしてもよく、好ましくは２μｍ以上である。 The non-aqueous electrolyte secondary battery of the present invention preferably has a negative electrode active material made of a carbonaceous material having an average particle size (Dv ₅₀ , particle size with a cumulative volume of 50%) of 6 μm or less. If the average particle diameter of the carbonaceous material is excessive, large particles increase, making it difficult to apply a thin electrode. Further, the diffusion distance of lithium in the particles increases, so that rapid charging / discharging occurs. It becomes difficult and the input / output characteristics are degraded. Therefore, the average particle diameter is preferably 4.5 μm or less, more preferably 4 μm or less. If the average particle diameter is too small, the proportion of fine powder increases and the irreversible capacity increases, so it may be 1 μm or more, preferably 2 μm or more.

　正極活物質を含む正極に対向する負極に含まれる負極活物質には、Ｘ線回折法により求められる００２面の平均層面間隔（ｄ_００２）が０．３４２ｎｍ以上０．３７５ｎｍ以下の乱層構造炭素質材料が好ましい。平均層面間隔は、結晶完全性が高いほど小さい値を示し、黒鉛構造では０．３３５４ｎｍであり、黒鉛構造が乱れるほどその値が増加する傾向にある。黒鉛質材料は、リチウムのドープ脱ドープの繰り返しにより、黒鉛層間が１０％程度膨張するため結晶構造の破壊が発生しやすい。そのため、本発明は、負極活物質として、黒鉛構造よりも平均面間隔の大きい乱層構造を有する炭素質材料を使用することにしたものであり、その００２面の平均層面間隔は、０．３４２ｎｍ以上０．３７５ｎｍ以下であることが好ましい。平均面間隔が０．３４２ｎｍ未満であると、放電中に電位が緩やかに傾斜する領域が短くなり、入出力特性が確保できなくなるため好ましくない。０．３４４ｎｍ以上がより好ましい。平均面間隔が０．３７５ｎｍを超えると、炭素化が十分でないことを示しており、不可逆容量が大きくなるため好ましくない。 The negative electrode active material contained in the negative electrode facing the positive electrode containing the positive electrode active material includes a stratified structure carbon having an average layer surface spacing (d ₀₀₂ ) of 002 planes of 0.342 nm or more and 0.375 nm or less determined by an X-ray diffraction method. A quality material is preferred. The average layer surface spacing shows a smaller value as the crystal perfection is higher, and is 0.3354 nm for the graphite structure, and the value tends to increase as the graphite structure is disturbed. Since the graphite material expands by about 10% due to repeated lithium doping and dedoping, the crystal structure is easily broken. Therefore, in the present invention, a carbonaceous material having a turbulent layer structure having a larger average plane spacing than the graphite structure is used as the negative electrode active material, and the average layer plane spacing on the 002 plane is 0.342 nm. The thickness is preferably 0.375 nm or less. If the average spacing is less than 0.342 nm, the region where the potential gently slopes during discharge becomes short, and input / output characteristics cannot be secured, which is not preferable. 0.344 nm or more is more preferable. An average interplanar spacing of more than 0.375 nm is not preferable because it indicates that carbonization is not sufficient and the irreversible capacity increases.

　本発明の非水電解質二次電池は、窒素ガスの吸着によるＢＥＴ法により求めた比表面積（ＢＥＴ）が６ｍ^２／ｇ以上である負極活物質を有することが好ましい。負極活物質の比表面積は、過小であると電解液との反応面積が小さくなり入出力特性が低下する傾向があるため、７ｍ^２／ｇ以上であるとよい。好ましくは８ｍ^２／ｇ以上である。負極活物質の比表面積は、過大であると得られる電池の不可逆容量が大きくなる傾向があるため、２０ｍ^２／ｇ以下であるとよい。好ましくは１５ｍ^２／ｇ以下である。 The nonaqueous electrolyte secondary battery of the present invention preferably has a negative electrode active material having a specific surface area (BET) of 6 m ² / g or more determined by a BET method by adsorption of nitrogen gas. If the specific surface area of the negative electrode active material is too small, the reaction area with the electrolytic solution tends to be small and the input / output characteristics tend to be low, so it is preferable that the specific surface area be 7 m ² / g or more. Preferably it is 8 m < ² > / g or more. Since the specific surface area of the negative electrode active material tends to increase the irreversible capacity of the battery obtained when it is excessive, it is preferably 20 m ² / g or less. Preferably it is 15 m < ² > / g or less.

（非水電解質二次電池）
　本発明の非水電解質二次電池は、正極活物質を含む正極、負極活物質を含む負極、及び電解質を備え、セパレータなど電池を構成する他の材料については、特に限定されることなく、非水電解質二次電池として従来使用され、あるいは提案されている種々の材料を使用することが可能である。 (Non-aqueous electrolyte secondary battery)
The nonaqueous electrolyte secondary battery of the present invention includes a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and an electrolyte, and other materials constituting the battery such as a separator are not particularly limited. Various materials conventionally used or proposed as a water electrolyte secondary battery can be used.

（正極活物質）
　正極活物質としては、本技術分野で使用される正極活物質が使用できる。例えば、リン酸鉄リチウム（ＬｉＦｅＰＯ_４）、リン酸マンガンリチウム（ＬｉＭｎＰＯ_４）、リン酸マンガン鉄リチウム（ＬｉＭｎ_１－ｘＦｅ_ｘＰＯ_４）リン酸コバルトリチウム（ＬｉＣｏＰＯ_４）、コバルト酸リチウム複合酸化物（ＬｉＣｏＯ_２）、スピネル型マンガン酸リチウム複合酸化物（ＬｉＭｎ_２Ｏ_４）、マンガン酸リチウム複合酸化物（ＬｉＭｎＯ_２、Ｌｉ_２ＭｎＯ_３）、ニッケル酸リチウム複合酸化物（ＬｉＮｉＯ_２）、ニオブ酸リチウム複合酸化物（ＬｉＮｂＯ_２）、鉄酸リチウム複合酸化物（ＬｉＦｅＯ_２）、マグネシウム酸リチウム複合酸化物（ＬｉＭｇＯ_２）、カルシウム酸リチウム複合酸化物（ＬｉＣａＯ_２）、銅酸リチウム複合酸化物（ＬｉＣｕＯ_２）、亜鉛酸リチウム複合酸化物（ＬｉＺｎＯ_２）、モリブデン酸リチウム複合酸化物（ＬｉＭｏＯ_２）、タンタル酸リチウム複合酸化物（ＬｉＴａＯ_２）、タングステン酸リチウム複合酸化物（ＬｉＷＯ_２）、リチウム－ニッケル－コバルト－アルミニウム複合酸化物（ＬｉＮｉ_０．８Ｃｏ_０．１５Ａｌ_０．０５Ｏ_２）、リチウム－ニッケル－コバルト－マンガン複合酸化物（ＬｉＮｉ_１／３Ｃｏ_１／３Ｍｎ_１／３Ｏ_２）、Ｌｉ過剰系ニッケル－コバルト－マンガン複合酸化物（Ｌｉ_ｘＮｉ_ＡＣｏ_ＢＭｎ_ＣＯ_２固溶体）、酸化マンガン（ＭｎＯ_２）、バナジウム系、硫黄系、シリケート系等の複合金属カルコゲン化合物が好ましく、これらのカルコゲン化合物を必要に応じて混合してもよい。これらの正極材料を適当なバインダーと電極に導電性を付与するための炭素材料とともに成形して、導電性の集電体上に層形成することにより正極が形成される。 (Positive electrode active material)
As the positive electrode active material, a positive electrode active material used in this technical field can be used. For example, lithium iron phosphate (LiFePO ₄ ), lithium manganese phosphate (LiMnPO ₄ ), lithium manganese iron phosphate (LiMn _1-x Fe _x PO ₄ ) lithium cobalt phosphate (LiCoPO ₄ ), lithium cobalt oxide composite oxide (LiCoO ₂ ), spinel type lithium manganate composite oxide (LiMn ₂ O ₄ ), lithium manganate composite oxide (LiMnO _2, Li ₂ MnO ₃ ), lithium nickelate composite oxide (LiNiO ₂ ), lithium niobate composite oxide (LiNbO _2), ferrate lithium composite oxide (LiFeO _2), lithium magnesium acid complex oxide (LiMgO _2), lithium composite oxide of calcium acid (LiCaO _2), cuprate lithium composite oxide (LiCuO ₂ ), Lithium zincate composite oxide ( iZnO _2), lithium composite oxide molybdate (LiMoO _2), lithium tantalate complex oxide (LiTaO _2), tungstic acid lithium composite oxide (LiWO _2), lithium - nickel - cobalt - aluminum composite oxide (LiNi _{0 .8} Co _0.15 Al _0.05 O ₂ ), lithium-nickel-cobalt-manganese composite oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), Li-rich nickel-cobalt-manganese composite oxide _{(Li x Ni a Co B Mn} C O 2 solid solution), manganese oxide _(MnO 2), vanadium compounds, sulfur compounds, complex metal chalcogen compounds silicate are preferable, depending on these chalcogen compounds necessary mixed May be. These positive electrode materials are molded together with a suitable binder and a carbon material for imparting conductivity to the electrode, and a positive electrode is formed by forming a layer on a conductive current collector.

（負極活物質）
　本発明の非水電解質二次電池で用いる炭素質材料は、特に限定されないが、従来の非水電解質二次電池の炭素質材料と類似の製造法をベースにしつつ、焼成条件を最適化することで良好に製造することができる。炭素前駆体から製造される炭素質材料を使用することができる。炭素前駆体としては、石油ピッチ若しくはタール、石炭ピッチ若しくはタール、熱可塑性樹脂を挙げることができる。熱可塑性樹脂としては、ポリアセタール、ポリアクリロニトリル、スチレン／ジビニルベンゼン共重合体、ポリイミド、ポリカーボネート、変性ポリフェニレンエーテル、ポリブチレンテレフタレート、ポリアリレート、ポリスルホン、ポリフェニレンスルフィド、フッ素樹脂、ポリアミドイミド、又はポリエーテルエーテルケトンを挙げることができる。また石炭を乾留して得られる石炭コークス、重油を熱分解した際に得られる残渣である石油コークスも炭素前駆体として用いることができる。また、負極活物質には、炭素質材料として、易黒鉛化性炭素に加えて、難黒鉛化性炭素、黒鉛などを混合することができる。また、炭素質材料以外の負極活物質を混合することもできる。 (Negative electrode active material)
The carbonaceous material used in the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, but the firing conditions should be optimized while being based on a manufacturing method similar to the carbonaceous material of the conventional nonaqueous electrolyte secondary battery. Can be manufactured satisfactorily. Carbonaceous materials made from carbon precursors can be used. Examples of the carbon precursor include petroleum pitch or tar, coal pitch or tar, and a thermoplastic resin. Thermoplastic resins include polyacetal, polyacrylonitrile, styrene / divinylbenzene copolymer, polyimide, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyarylate, polysulfone, polyphenylene sulfide, fluororesin, polyamideimide, or polyetheretherketone Can be mentioned. Further, coal coke obtained by dry distillation of coal and petroleum coke which is a residue obtained when pyrolyzing heavy oil can also be used as the carbon precursor. In addition to the graphitizable carbon, non-graphitizable carbon, graphite, and the like can be mixed with the negative electrode active material as the carbonaceous material. Moreover, negative electrode active materials other than a carbonaceous material can also be mixed.

　本発明においては、焼成後に易黒鉛化性炭素材料となる炭素前駆体はいずれも使用できるが、石油ピッチ若しくはタール、石炭ピッチ若しくはタール、又は熱可塑性樹脂は、製造過程において、熱に対し不融とするための不融化処理を行ってもよい。不融化処理は、酸化によって炭素前駆体に架橋を形成させることによって行うことができる。不融化処理は、本発明の分野において、公知の方法によって行うことができる。 In the present invention, any carbon precursor that becomes a graphitizable carbon material after firing can be used, but petroleum pitch or tar, coal pitch or tar, or thermoplastic resin is infusible to heat during the production process. Infusibilization treatment may be performed. The infusibilization treatment can be performed by forming a crosslink on the carbon precursor by oxidation. The infusibilization treatment can be performed by a known method in the field of the present invention.

　炭素前駆体を負極用炭素質材料とするために焼成が行われる。本発明においては、３００℃以上９００℃未満の温度での予備焼成、及び８００～１５００℃の温度での本焼成によって行うことが好ましい。予備焼成温度が低すぎると脱タールが不十分となり、本焼成時に多くのタールを発生することとなり、電池性能低下を引き起こすので好ましくない。予備焼成温度は３００℃以上が好ましく、更に好ましくは４００℃以上である。一方、予備焼成温度が高すぎるとタール発生温度領域を超えることになり、使用するエネルギー効率が低下するため好ましくない。更に、発生したタールが二次分解反応を引き起こしそれらが、炭素前駆体に付着し、性能低下を引き起こすことがあるので好ましくない。粉砕工程は、予備焼成工程の前に行ってもよいが、予備焼成後に行う方が好ましい。予備焼成温度が高すぎると炭素前駆体が硬くなるので粉砕効率が低下することがあるため、好ましくない。予備焼成は９００℃未満で行うことが好ましい。予備焼成及び本焼成を行う場合は、予備焼成の後に一旦温度を低下させて、粉砕し、本焼成を行ってもよい。
　本焼成工程は、通常の本焼成の手順に従って行うことができる。本焼成の温度は、８００～１５００℃が好ましい。本焼成温度が８００℃未満では、炭素化が十分でなく、炭素質材料に官能基が多く残存してＨ／Ｃの値が高くなり、リチウムとの反応により不可逆容量が増加するため好ましくない。本発明の本焼成温度の下限は８００℃以上であり、より好ましくは９００℃以上である。一方、本焼成温度が１５００℃を超えると炭素六角平面の選択的配向性が高まり放電容量が低下し、また真密度が大きくなって充放電中の膨張収縮が大きくなり充放電サイクル特性が劣るため好ましくない。本発明の本焼成温度の上限は１５００℃以下であり、より好ましくは１４５０℃以下であり、さらに好ましくは１４００℃以下である。 Firing is performed to make the carbon precursor a carbonaceous material for a negative electrode. In the present invention, it is preferable to perform pre-baking at a temperature of 300 ° C. or higher and lower than 900 ° C. and main baking at a temperature of 800 to 1500 ° C. If the pre-baking temperature is too low, tar removal is insufficient, and a large amount of tar is generated during the main baking, which is not preferable because battery performance is reduced. The pre-baking temperature is preferably 300 ° C. or higher, more preferably 400 ° C. or higher. On the other hand, if the pre-baking temperature is too high, the tar generation temperature range is exceeded, and the energy efficiency to be used is lowered, which is not preferable. Further, the generated tar causes a secondary decomposition reaction, which adheres to the carbon precursor and may cause a decrease in performance, which is not preferable. The pulverization step may be performed before the pre-baking step, but is preferably performed after the pre-baking. If the pre-baking temperature is too high, the carbon precursor becomes hard and the pulverization efficiency may be lowered. Pre-baking is preferably performed at less than 900 ° C. When pre-baking and main baking are performed, the temperature may be once lowered after the pre-baking, pulverized, and main baking may be performed.
The main baking step can be performed according to a normal main baking procedure. The firing temperature is preferably 800 to 1500 ° C. If the main calcination temperature is less than 800 ° C., carbonization is not sufficient, many functional groups remain in the carbonaceous material, the H / C value increases, and the irreversible capacity increases due to reaction with lithium, which is not preferable. The lower limit of the main firing temperature of the present invention is 800 ° C. or higher, more preferably 900 ° C. or higher. On the other hand, when the main firing temperature exceeds 1500 ° C., the selective orientation of the carbon hexagonal plane is increased, the discharge capacity is lowered, the true density is increased, the expansion / contraction during charge / discharge is increased, and charge / discharge cycle characteristics are inferior. It is not preferable. The upper limit of the main calcination temperature of the present invention is 1500 ° C. or lower, more preferably 1450 ° C. or lower, and further preferably 1400 ° C. or lower.

（電極の製造）
　本発明の非水電解質二次電池における電極は、正極活物質または負極活物質に結合剤（バインダー）を添加し適当な溶媒を適量添加、混練し、電極合剤とした後に、金属板などからなる集電体に塗布・乾燥後、加圧成形することにより製造することができる。
　集電体は、アルミニウム、銅、ニッケル、ステンレスなどの金属材料、導電性高分子材料などが使用される。
　また、高い導電性を賦与することを目的として、電極合剤の調製時に必要に応じて導電助剤を添加することができる。導電助剤としては、導電性のカーボンブラック、気相成長炭素繊維（ＶＧＣＦ）、ナノチューブなどを用いることができ、添加量は使用する導電助剤の種類によっても異なるが、添加する量が少なすぎると期待する導電性が得られないので好ましくなく、多すぎると電極合剤中の分散が悪くなるので好ましくない。このような観点から、添加する導電助剤の好ましい割合は０．５～１０重量％（ここで、活物質量＋バインダー量＋導電助剤量＝１００重量％とする）であり、更に好ましくは０．５～７重量％、とくに好ましくは０．５～５重量％である。
　結合剤としては、ＰＶＤＦ（ポリフッ化ビニリデン）、ポリテトラフルオロエチレン、及びＳＢＲ（スチレン・ブタジエン・ラバー）とＣＭＣ（カルボキシメチルセルロース）との混合物などの電解液と反応しないものであれば特に限定されない。中でもＰＶＤＦは、活物質表面に付着したＰＶＤＦがリチウムイオン移動を阻害することが少なく、良好な入出力特性を得るために好ましい。ＰＶＤＦを溶解しスラリーを形成するためにＮ－メチルピロリドン（ＮＭＰ）などの極性溶媒が好ましく用いられるが、ＳＢＲなどの水性エマルジョンやＣＭＣを水に溶解して用いることもできる。結合剤の添加量が多すぎると、得られる電極の抵抗が大きくなるため、電池の内部抵抗が大きくなり電池特性を低下させるので好ましくない。また、結合剤の添加量が少なすぎると、負極材料粒子相互及び集電材との結合が不十分となり好ましくない。結合剤の好ましい添加量は、使用するバインダーの種類によっても異なるが、ＰＶＤＦ系のバインダーでは好ましくは３～１３重量％であり、更に好ましくは３～１０重量％である。一方、溶媒に水を使用するバインダーでは、ＳＢＲとＣＭＣとの混合物など、複数のバインダーを混合して使用することが多く、使用する全バインダーの総量として０．５～５重量％が好ましく、更に好ましくは１～４重量％である。電極活物質層は集電板の両面に形成するのが基本であるが、必要に応じて片面でもよい。 (Manufacture of electrodes)
The electrode in the non-aqueous electrolyte secondary battery of the present invention is obtained by adding a binder (binder) to a positive electrode active material or a negative electrode active material, adding an appropriate amount of an appropriate solvent, kneading to obtain an electrode mixture, and then using a metal plate or the like. It can be manufactured by applying pressure to the current collector to be formed and drying it.
As the current collector, a metal material such as aluminum, copper, nickel, and stainless steel, a conductive polymer material, or the like is used.
Moreover, a conductive support agent can be added as needed at the time of preparation of an electrode mixture for the purpose of providing high electroconductivity. As the conductive assistant, conductive carbon black, vapor grown carbon fiber (VGCF), nanotube, etc. can be used, and the amount added varies depending on the type of conductive assistant used, but the amount added is too small. Since the expected conductivity cannot be obtained, it is not preferable, and too much is not preferable because the dispersion in the electrode mixture becomes worse. From such a point of view, a preferable ratio of the conductive auxiliary agent to be added is 0.5 to 10% by weight (where the amount of active material + the amount of binder + the amount of conductive auxiliary agent = 100% by weight), and more preferably It is 0.5 to 7% by weight, particularly preferably 0.5 to 5% by weight.
The binder is not particularly limited as long as it does not react with an electrolytic solution such as PVDF (polyvinylidene fluoride), polytetrafluoroethylene, and a mixture of SBR (styrene-butadiene rubber) and CMC (carboxymethylcellulose). Among them, PVDF is preferable because PVDF attached to the surface of the active material hardly inhibits lithium ion migration and obtains favorable input / output characteristics. In order to dissolve PVDF and form a slurry, a polar solvent such as N-methylpyrrolidone (NMP) is preferably used, but an aqueous emulsion such as SBR or CMC can also be dissolved in water. When the amount of the binder added is too large, the resistance of the obtained electrode is increased, which is not preferable because the internal resistance of the battery is increased and the battery characteristics are deteriorated. Moreover, when there is too little addition amount of binder, the coupling | bonding with negative electrode material particle | grains and a collector is insufficient, and it is unpreferable. The preferred addition amount of the binder varies depending on the type of binder used, but is preferably 3 to 13% by weight, more preferably 3 to 10% by weight for the PVDF-based binder. On the other hand, a binder using water as a solvent is often used by mixing a plurality of binders such as a mixture of SBR and CMC, and the total amount of all binders used is preferably 0.5 to 5% by weight, The amount is preferably 1 to 4% by weight. The electrode active material layer is basically formed on both sides of the current collector plate, but may be on one side if necessary.

（非水電解質）
　これら正極と負極との組み合わせで用いられる非水電解質には、一般に非水溶媒に電解質を溶解することにより形成される。非水溶媒としては、例えばプロピレンカーボネート、エチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、ジメトキシエタン、ジエトキシエタン、γ－ブチルラクトン、テトラヒドロフラン、２－メチルテトラヒドロフラン、スルホラン、又は１，３－ジオキソランなどの有機溶媒の一種又は二種以上を組み合わせて用いることができる。また、電解質としては、ＬｉＣｌＯ_４、ＬｉＰＦ_６、ＬｉＢＦ_４、ＬｉＣＦ_３ＳＯ_３、ＬｉＡｓＦ_６、ＬｉＣｌ、ＬｉＢｒ、ＬｉＢ（Ｃ_６Ｈ_５）_４、又はＬｉＮ（ＳＯ_３ＣＦ_３）_２などが用いられる。また、本発明の非水電解質二次電池には、ゲル電解質、固体電解質を用いることができる。
　本発明の非水電解質二次電池は、一般に上記のようにして形成した正極活物質層と負極活物質層とを必要に応じて不織布、その他の多孔質材料などからなる透液性セパレータを介して対向させ電解液中に浸漬させることにより形成される。
　セパレータとしては、二次電池に通常用いられる不織布、その他の多孔質材料からなる透過性セパレータを用いることができる。あるいはセパレータの代わりに、もしくはセパレータと一緒に、電解液を含浸させたポリマーゲルからなる固体電解質を用いることもできる。 (Nonaqueous electrolyte)
The nonaqueous electrolyte used in combination of these positive electrode and negative electrode is generally formed by dissolving the electrolyte in a nonaqueous solvent. Examples of the non-aqueous solvent include organic solvents such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dimethoxyethane, diethoxyethane, γ-butyllactone, tetrahydrofuran, 2-methyltetrahydrofuran, sulfolane, or 1,3-dioxolane. These can be used alone or in combination of two or more. As the electrolyte, LiClO ₄ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , LiCl, LiBr, LiB (C ₆ H ₅ ) ₄ , or LiN (SO ₃ CF ₃ ) ₂ is used. Moreover, a gel electrolyte and a solid electrolyte can be used for the nonaqueous electrolyte secondary battery of the present invention.
The non-aqueous electrolyte secondary battery of the present invention generally has a positive electrode active material layer and a negative electrode active material layer formed as described above with a liquid-permeable separator made of a nonwoven fabric or other porous material as necessary. To be opposed to each other and immersed in an electrolytic solution.
As the separator, a non-woven fabric usually used for a secondary battery or a permeable separator made of another porous material can be used. Alternatively, a solid electrolyte made of a polymer gel impregnated with an electrolytic solution can be used instead of or together with the separator.

　本発明の非水電解質二次電池は、例えば電気自動車やＨＥＶなどの車両に搭載される二次電池として好適である。通常電動車両として知られるものや燃料電池や内燃機関とのハイブリッド車など、特に制限されることなく対象とすることができるが、少なくとも上記電池を備えた電源装置と、該電源装置からの電源供給により駆動する電動駆動機構と、これを制御する制御装置を備える。更に、発電ブレーキや回生ブレーキを備え、制動によるエネルギーを電気に変換して当該リチウムイオン二次電池に充電する機構を備えてもよい。ハイブリッド車は特に電池容積の自由度が低いため、本発明の電池が有用である。 The nonaqueous electrolyte secondary battery of the present invention is suitable as a secondary battery mounted on a vehicle such as an electric vehicle or HEV. It can be targeted without particular limitation, such as what is usually known as an electric vehicle, a hybrid battery with a fuel cell or an internal combustion engine, and at least a power supply device including the battery and power supply from the power supply device An electric drive mechanism that is driven by the motor and a control device that controls the electric drive mechanism. Further, a power generation brake or a regenerative brake may be provided, and a mechanism for converting the energy generated by braking into electricity and charging the lithium ion secondary battery may be provided. Since the hybrid vehicle has a particularly low degree of freedom in battery volume, the battery of the present invention is useful.

　以下、実施例によって本発明を具体的に説明するが、これらは本発明の範囲を限定するものではない。 Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.

　以下に本発明の非水電解質二次電池における正極活物質、負極活物質の物性値（ρ_Ｂｔ、ＢＥＴ比表面積、平均粒子径（Ｄ_ｖ５０）、ｄ_００２、活物質層厚み、正極容量、負極容量、ＳＯＣ５０％時の重量当たりの入力密度、容量維持率）の測定法を記載するが、実施例を含めて、本明細書中に記載する物性値は、以下の方法により求めた値に基づくものである。 The physical property values (ρ _Bt , BET specific surface area, average particle diameter (D _v50 ), d ₀₀₂ , active material layer thickness, positive electrode capacity, negative electrode of the positive electrode active material and the negative electrode active material in the nonaqueous electrolyte secondary battery of the present invention are shown below. The measurement method of capacity, input density per weight when SOC is 50%, capacity retention ratio is described. Physical properties described in this specification including examples are based on values obtained by the following methods. Is.

（ブタノール法による真密度（ρ_Ｂｔ））
　真密度は、ＪＩＳ　Ｒ　７２１２に定められた方法に従い、ブタノール法により測定した。内容積約４０ｍＬの側管付比重びんの質量（ｍ_１）を正確に量る。次に、その底部に試料を約１０ｍｍの厚さになるように平らにいれた後、その質量（ｍ_２）を正確に量る。これに１－ブタノールを静かに加えて、底から２０ｍｍ程度の深さにする。次に比重びんに軽い振動を加えて、大きな気泡の発生がなくなったのを確かめた後、真空デシケーター中にいれ、徐々に排気して２．０～２．７ｋＰａとする。その圧力に２０分間以上保ち、気泡の発生が止まった後に、取り出し、更に１－ブタノールを満たし、栓をして恒温水槽（３０±０．０３℃に調節してあるもの）に１５分間以上浸し、１－ブタノールの液面を標線に合わせる。次に、これを取り出して外部をよくぬぐって室温まで冷却した後質量（ｍ_４）を正確に量る。 (True density by the butanol method (ρ _Bt ))
The true density was measured by a butanol method according to a method defined in JIS R 7212. The mass (m ₁ ) of a specific gravity bottle with a side tube having an internal volume of about 40 mL is accurately measured. Next, the sample is placed flat on the bottom so as to have a thickness of about 10 mm, and its mass (m ₂ ) is accurately measured. Gently add 1-butanol to this to a depth of about 20 mm from the bottom. Next, light vibration is applied to the specific gravity bottle, and it is confirmed that large bubbles are not generated. Then, the bottle is placed in a vacuum desiccator and gradually evacuated to 2.0 to 2.7 kPa. Keep at that pressure for 20 minutes or more, and after the generation of bubbles has stopped, take it out, fill it with 1-butanol, plug it and immerse it in a constant temperature water bath (adjusted to 30 ± 0.03 ° C) for 15 minutes or more. Adjust the liquid level of 1-butanol to the marked line. Next, this is taken out, the outside is well wiped off and cooled to room temperature, and then the mass (m ₄ ) is accurately measured.

　次に、同じ比重びんに１－ブタノールだけを満たし、前記と同じようにして恒温水槽に浸し、標線を合わせた後質量（ｍ_３）を量る。また、使用直前に沸騰させて溶解した気体を除いた蒸留水を比重びんに採取し、前記と同様に恒温水槽に浸し、標線を合わせた後質量（ｍ_５）を量る。ρ_Ｂｔは、次の式により計算する。 Next, the same specific gravity bottle is filled with only 1-butanol, immersed in a constant temperature water bath in the same manner as described above, and the mass (m ₃ ) is measured after aligning the marked lines. Moreover, distilled water excluding the gas that has been boiled and dissolved immediately before use is collected in a specific gravity bottle, immersed in a constant temperature water bath in the same manner as described above, and the mass (m ₅ ) is measured after aligning the marked lines. ρ _Bt is calculated by the following equation.

このとき、ｄは、水の３０℃における比重（０．９９４６）である。
となる。

At this time, d is the specific gravity (0.9946) of water at 30 ° C.
It becomes.

（窒素吸着による比表面積（ＳＳＡ））
　以下にＢＥＴの式から誘導された近似式を記す。 (Specific surface area by nitrogen adsorption (SSA))
An approximate expression derived from the BET expression is described below.

　上記の近似式を用いて、液体窒素温度における、窒素吸着による１点法（相対圧力ｘ＝０．３）によりｖ_ｍを求め、次式により試料の比表面積を計算した。

Using the above approximate expression, at liquid nitrogen temperature, 1-point method by nitrogen adsorption seek v _m by (relative pressure x = 0.3), was calculated a specific surface area of the sample by the following equation.

　このとき、ｖ_ｍは試料表面に単分子層を形成するに必要な吸着量（ｃｍ^３／ｇ）、ｖは実測される吸着量（ｃｍ^３／ｇ）、ｘは相対圧力である。

In this case, _{v m} is the adsorption amount necessary for forming a monomolecular layer on the surface of the sample ^(cm 3 / g), v the adsorption amount of the measured ^(cm 3 / g), x is a relative pressure.

　具体的には、ＭＩＣＲＯＭＥＲＩＴＩＣＳ社製「Ｆｌｏｗ　Ｓｏｒｂ　ＩＩ２３００」を用いて、以下のようにして液体窒素温度における炭素質材料への窒素の吸着量を測定した。粒子径約５～５０μｍに粉砕した炭素質材料を試料管に充填し、ヘリウム：窒素＝７０：３０の混合ガスを流しながら、試料管を－１９６℃に冷却し、炭素質材料に窒素を吸着させる。つぎに試料管を室温に戻す。このとき試料から脱離してくる窒素量を熱伝導度型検出器で測定し、吸着ガス量ｖとした。 Specifically, using a “Flow Sorb II2300” manufactured by MICROMERITICS, the amount of nitrogen adsorbed on the carbonaceous material at the liquid nitrogen temperature was measured as follows. The sample tube is filled with a carbonaceous material pulverized to a particle size of about 5 to 50 μm, and the sample tube is cooled to −196 ° C. while flowing a mixed gas of helium: nitrogen = 70: 30, and nitrogen is adsorbed on the carbonaceous material. Let The sample tube is then returned to room temperature. At this time, the amount of nitrogen desorbed from the sample was measured with a thermal conductivity detector, and the amount of adsorbed gas v was obtained.

（Ｘ線回折法による平均層面間隔（ｄ_００２））
　炭素質材料粉末を試料ホルダーに充填し、Ｎｉフィルターにより単色化したＣｕＫα線を線源とし、Ｘ線回折図形を得る。回折図形のピーク位置は重心法（回折線の重心位置を求め、これに対応する２θ値でピーク位置をもとめる方法）により求め、標準物質用高純度シリコン粉末の（１１１）面の回折ピークを用いて補正する。ＣｕＫα線の波長を０．１５４１８ｎｍとし、以下に記すＢｒａｇｇの公式によりｄ_００２を算出する。 (Average layer surface spacing by X-ray diffraction method (d ₀₀₂ ))
An X-ray diffraction pattern is obtained by filling a carbonaceous material powder into a sample holder and using CuKα rays monochromated by a Ni filter as a radiation source. The peak position of the diffraction pattern is obtained by the barycentric method (a method of finding the barycentric position of the diffraction line and determining the peak position with the corresponding 2θ value), and using the diffraction peak on the (111) plane of the high-purity silicon powder for standard substances. To correct. The wavelength of the CuKα ray is set to 0.15418 nm, and d ₀₀₂ is calculated according to the Bragg formula described below.

λ：Ｘ線の波長，θ：回折角

λ: X-ray wavelength, θ: diffraction angle

（レーザー回折法による平均粒子径（Ｄ_ｖ５０））
　試料に分散剤（界面活性剤ＳＮウェット３６６（サンノプコ社製））を加え馴染ませる。次に純水を加えて、超音波により分散させた後、粒径分布測定器（島津製作所社製「ＳＡＬＤ－３０００Ｓ」）で、屈折率を２．０－０．１ｉとし、粒径０．５～３０００μｍの範囲の粒径分布を求めた。得られた粒径分布から、累積容積が５０％となる粒径をもって、平均粒子径Ｄ_ｖ５０とした。 (Average particle diameter by laser diffraction method ( _Dv50 ))
Dispersant (surfactant SN wet 366 (manufactured by San Nopco)) is added to the sample to acclimate. Next, after adding pure water and dispersing with ultrasonic waves, the refractive index is set to 2.0-0.1i with a particle size distribution measuring instrument (“SALD-3000S” manufactured by Shimadzu Corporation), and the particle size is set to 0.00. A particle size distribution in the range of 5 to 3000 μm was determined. From the obtained particle size distribution, the average particle size _Dv50 was _{defined as the} particle size with a cumulative volume of 50%.

　実施例１～１０及び比較例１～９のリチウムを含む遷移金属複合酸化物からなる正極活物質、炭素質材料からなる負極活物質を用いて、電極を作製し、試験用の非電解質二次電池（フルセル、テストセル）を作製し、電池性能の評価を行った。 An electrode was prepared using a positive electrode active material made of a transition metal composite oxide containing lithium and a negative electrode active material made of a carbonaceous material in Examples 1 to 10 and Comparative Examples 1 to 9, and a non-electrolyte secondary material for testing was prepared. Batteries (full cell, test cell) were prepared and battery performance was evaluated.

（実施例１）
　以下の（ａ）～（ｊ）の操作を行って、所定項目を測定した。
（ａ）正極電極の作製
　正極活物質には、ニッケル、コバルト、マンガンの原子比が１：１：１のリチウム－ニッケル－コバルト－マンガン複合酸化物（ＮＣＭ）を用いた。
　正極電極は、上記の正極活物質１００質量部に導電材としてのアセチレンブラック３質量部を加え、この混合物にＮ－メチルピロリドン（ＮＭＰ）の溶剤に結着剤としてのポリフッ化ビニリデン（ＰＶＤＦ）（株式会社クレハ製「ＫＦ＃１１００」）を溶解した溶液を混練してペースト状にした。加えたＰＶＤＦの量は活物質１００質量部に対して４質量部となるように調製した。次いで、このペーストをアルミニウム箔上に均一に塗布した。乾燥した後、アルミニウム箔より直径１５ｍｍの円板状に打ち抜き、これをプレスして正極とした。 Example 1
The following items (a) to (j) were performed to measure predetermined items.
(A) Production of positive electrode Lithium-nickel-cobalt-manganese composite oxide (NCM) having a 1: 1: 1 atomic ratio of nickel, cobalt, and manganese was used as the positive electrode active material.
For the positive electrode, 3 parts by mass of acetylene black as a conductive material is added to 100 parts by mass of the positive electrode active material, and polyvinylidene fluoride (PVDF) (PVDF) (as a binder in a solvent of N-methylpyrrolidone (NMP) is added to this mixture. A solution in which “KF # 1100” manufactured by Kureha Co., Ltd.) was dissolved was kneaded into a paste. The amount of PVDF added was adjusted to 4 parts by mass with respect to 100 parts by mass of the active material. Next, this paste was uniformly applied on the aluminum foil. After drying, it was punched out into a disk shape having a diameter of 15 mm from an aluminum foil, and this was pressed to obtain a positive electrode.

（ｂ）負極電極の作製
　負極活物質には、等方性ピッチを原料として熱処理を行った非晶質炭素を用いた。平均粒径は１０．８μｍであり、（ｄ_００２）が０．３７０ｎｍであり真密度は１．７１ｇ／ｃｃであった。
　負極電極は、正極電極の作製とほぼ同様に、炭素質粉末１００質量部にＮＭＰの溶剤に結着剤としてのＰＶＤＦを溶解した溶液を混練してペースト状にした。加えたＰＶＤＦの量は炭素粉末１００質量部に対して８質量部となるように調製した。次いで、このペーストを銅箔上に均一に塗布した。乾燥した後、銅箔より直径１５ｍｍの円板状に打ち抜き、これをプレスして負極とした。 (B) Production of negative electrode As the negative electrode active material, amorphous carbon subjected to heat treatment using an isotropic pitch as a raw material was used. The average particle size was 10.8 μm, (d ₀₀₂ ) was 0.370 nm, and the true density was 1.71 g / cc.
In the same manner as the production of the positive electrode, the negative electrode was made into a paste by kneading 100 parts by mass of carbonaceous powder with a solution of PVDF as a binder in an NMP solvent. The amount of PVDF added was adjusted to 8 parts by mass with respect to 100 parts by mass of the carbon powder. Subsequently, this paste was uniformly applied on the copper foil. After drying, it was punched out into a disk shape having a diameter of 15 mm from a copper foil, and this was pressed to obtain a negative electrode.

（ｃ）負極活物質層の厚みの測定
　負極活物質層の厚みは、負極電極の集電体の両面に負極活物質層が存在する場合には、負極から集電体の厚みを差し引いた厚みの半分に相当し、また、集電体の片面にのみ負極活物質層が存在する場合には、負極から集電体の厚みを差し引いた厚みに相当する。
　具体的には、厚さ測定器により厚みを測定した。 (C) Measurement of the thickness of the negative electrode active material layer The thickness of the negative electrode active material layer is the thickness obtained by subtracting the thickness of the current collector from the negative electrode when there are negative electrode active material layers on both sides of the current collector of the negative electrode. In addition, when the negative electrode active material layer is present only on one side of the current collector, this corresponds to the thickness obtained by subtracting the thickness of the current collector from the negative electrode.
Specifically, the thickness was measured with a thickness measuring instrument.

（ｄ）フルセルの作製
　リチウム二次電池としての入力特性、サイクル後の容量維持率を測定するために、上記の正極と負極を組み合わせて、試験用のフルセルを作成した。正負極の活物質面が対向するように正極、直径１９ｍｍの硼珪酸塩ガラス繊維製微細細孔膜のセパレータ、負極を積層し、正負極とセパレータに電解液が含浸するように注液した。電解液は、エチレンカーボネートとジメチルカーボネートとメチルエチルカーボネートを容量比で１：２：２で混合した混合溶媒に１．４ｍｏｌ／Ｌの割合でＬｉＰＦ_６を加えたものを使用した。さらに正極側に厚み０．２ｍｍのアルミ板を重ね、ポリエチレン製のガスケットを用いて、Ａｒグローブボックス中で、２０１６サイズのフルセルを組み立てた。 (D) Production of full cell In order to measure the input characteristics as a lithium secondary battery and the capacity retention after the cycle, a full cell for testing was produced by combining the positive electrode and the negative electrode. A positive electrode, a separator of a fine pore film made of borosilicate glass fiber having a diameter of 19 mm, and a negative electrode were laminated so that the active material surfaces of the positive and negative electrodes were opposed to each other, and the positive and negative electrodes and the separator were injected so that the electrolyte solution was impregnated. As the electrolytic solution, a solution obtained by adding LiPF ₆ at a ratio of 1.4 mol / L to a mixed solvent in which ethylene carbonate, dimethyl carbonate, and methyl ethyl carbonate were mixed at a volume ratio of 1: 2: 2 was used. Furthermore, an aluminum plate having a thickness of 0.2 mm was stacked on the positive electrode side, and a 2016-size full cell was assembled in an Ar glove box using a polyethylene gasket.

（ｅ）初期放電容量、体積当たりの容量の測定
　上記のフルセルについて、充放電試験装置（東洋システム製「ＴＯＳＣＡＴ」）を用いて、定電流定電圧法により充放電試験を行った。具体的には、フルセルを０．３ｍＡ定電流、４．２Ｖ定電圧で充電し、電流が０．０３ｍＡまで減衰した時点で充電を終了した。その後、電池回路を開放し、０．３ｍＡで２．５Ｖに達するまで定電流放電を行った。このとき放電した電気量でもって初期放電容量（ｍＡｈ）を測定した。初期放電容量をフルセル内部に配置した正極、セパレータ、負極からなる構成要素の体積の和で除して体積当たりの容量を算出した。 (E) Measurement of initial discharge capacity and capacity per volume The above full cell was subjected to a charge / discharge test by a constant current constant voltage method using a charge / discharge test apparatus (“TOSCAT” manufactured by Toyo System). Specifically, the full cell was charged with a constant current of 0.3 mA and a constant voltage of 4.2 V, and the charging was terminated when the current was attenuated to 0.03 mA. Thereafter, the battery circuit was opened, and constant current discharge was performed until the voltage reached 2.5 V at 0.3 mA. The initial discharge capacity (mAh) was measured by the amount of electricity discharged at this time. The capacity per volume was calculated by dividing the initial discharge capacity by the sum of the volume of the constituent elements consisting of the positive electrode, separator, and negative electrode arranged inside the full cell.

（ｆ）体積当たり入力密度の測定
　初期放電容量を測定した上記のフルセルを用いて、充放電電流を０．６ｍＡに変える以外は、上記と同じ条件で１回充放電した。フルセルを初期放電容量の半分の電気量まで０．６ｍＡの定電流、４．２Ｖの定電圧で充電した。
　次いで、このフルセルに対して、図１に示すような入出力電流パルスを印加しながら、充電（入力）パルスの印加直前の電圧と各充電（入力）パルス印加１０秒後の電圧を読取った（各電圧読み取りは、図１中、電流パルスの立ち上がり・立下りの直前に行う）。電圧読取ポイントとして、図１に示すような４点で測定した電圧を印加電流値に対してプロットした。これらプロットの近似直線を外挿し、充電上限電圧４．２Ｖとの交点の電流値と充電上限電圧との積を入力値（Ｗ：ワット）として算出した。この入力値を、フルセル内部に配置した正極、セパレータ、負極からなる構成要素の体積の和で除して体積当たりの入力密度を算出した。 (F) Measurement of input density per volume Using the above-mentioned full cell whose initial discharge capacity was measured, charge / discharge was performed once under the same conditions as above except that the charge / discharge current was changed to 0.6 mA. The full cell was charged with a constant current of 0.6 mA and a constant voltage of 4.2 V up to half the initial discharge capacity.
Next, while applying the input / output current pulse as shown in FIG. 1 to this full cell, the voltage immediately before the application of the charging (input) pulse and the voltage 10 seconds after the application of each charging (input) pulse were read ( Each voltage reading is performed immediately before the rise and fall of the current pulse in FIG. 1). As voltage reading points, voltages measured at four points as shown in FIG. 1 were plotted against applied current values. The approximate straight lines of these plots were extrapolated, and the product of the current value at the intersection with the charging upper limit voltage 4.2 V and the charging upper limit voltage was calculated as an input value (W: Watt). The input value per volume was calculated by dividing this input value by the sum of the volumes of the components consisting of the positive electrode, separator, and negative electrode arranged inside the full cell.

（ｇ）容量維持率の測定
　上記の入力密度を評価した後のフルセルを用いて、充電を定電流定電圧法により行った。充電上限電圧を４．２Ｖ、充電電流値を５ｍＡに設定し、４．２Ｖに到達後、一定電圧のまま充電し、電流が０．５ｍＡまで減衰した時点で充電を終了した。その後、５ｍＡで定電流放電を行い、２．５Ｖに達した時点で終了した。このときの放電容量を測定した。このような充放電サイクルを３００サイクル繰り返し、３００サイクル目の放電容量を１サイクル目の放電容量で除して、その割合を容量維持率（％）として算出した。
　なお、上記の初期放電容量、重量当たり入力密度、正極容量、負極容量、容量維持率について充放電試験および測定は、いずれも２５℃の恒温槽内で行った。 (G) Measurement of capacity retention rate Charging was performed by a constant current constant voltage method using the full cell after the above input density was evaluated. The charging upper limit voltage was set to 4.2 V and the charging current value was set to 5 mA. After reaching 4.2 V, charging was performed with a constant voltage, and the charging was terminated when the current was attenuated to 0.5 mA. Thereafter, constant current discharge was performed at 5 mA, and the process was terminated when 2.5 V was reached. The discharge capacity at this time was measured. Such a charge / discharge cycle was repeated 300 times, the discharge capacity at the 300th cycle was divided by the discharge capacity at the first cycle, and the ratio was calculated as the capacity retention rate (%).
The charge / discharge test and measurement of the initial discharge capacity, the input density per weight, the positive electrode capacity, the negative electrode capacity, and the capacity retention rate were all performed in a thermostatic chamber at 25 ° C.

（ｈ）テストセルの作製
　上記（ｄ）と同様の手順で別のフルセルを作製し、上記「（ｅ）初期放電容量の測定」と同様の手順で充電した後、当該フルセルを解体して正極と負極を取り出した。リチウム極の調製は、Ａｒ雰囲気中のグローブボックス内で行った。予め２０１６サイズのコイン型電池用缶の外蓋に直径１６ｍｍのステンレススチール網円盤をスポット溶接した後、厚さ０．８ｍｍの金属リチウム薄板を直径１５ｍｍの円盤状に打ち抜いたものをステンレススチール網円盤に圧着し、電極（対極）とした。このようにして製造したリチウム極と正極との対、あるいは当該リチウム極と負極との対を用い、電解液としてはエチレンカーボネートとジメチルカーボネートとメチルエチルカーボネートを容量比で１：２：２で混合した混合溶媒に１．４ｍｏｌ／Ｌの割合でＬｉＰＦ_６を加えたものを使用し、直径１９ｍｍの硼珪酸塩ガラス繊維製微細細孔膜のセパレータとして、ポリエチレン製のガスケットを用いて、Ａｒグローブボックス中で、２０１６サイズのコイン型テストセルを組み立てた。 (H) Production of test cell Another full cell was produced in the same procedure as in (d) above, and charged in the same procedure as in the above "(e) Measurement of initial discharge capacity". And the negative electrode were taken out. The lithium electrode was prepared in a glove box in an Ar atmosphere. A 16 mm diameter stainless steel mesh disk is spot-welded to the outer lid of a 2016 coin-sized battery can, and then a 0.8 mm thick metal lithium sheet is punched into a 15 mm diameter disk shape. To be an electrode (counter electrode). Using the lithium electrode and positive electrode pair produced in this way or the lithium electrode and negative electrode pair, ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate were mixed at a volume ratio of 1: 2: 2 as the electrolyte. A mixture of LiPF ₆ added to the mixed solvent at a rate of 1.4 mol / L is used, and a polyethylene gasket is used as a separator for a microporous membrane made of borosilicate glass fiber having a diameter of 19 mm. Inside, a 2016 size coin type test cell was assembled.

（ｉ）正極容量の測定
　上記（ｈ）のリチウム極と正極の対からなるテストセルを用いて、放電を０．３ｍＡの定電流で行い、電圧が放電開始時の８０％電圧に低減した時点で終了した。このときの放電量から放電容量を測定し、当該放電容量を正極電極面積で除して、正極容量Ａ（ｍＡｈ／ｃｍ^２）を算出した。 (I) Measurement of positive electrode capacity Using the test cell comprising the lithium electrode and positive electrode pair in (h) above, the discharge was performed at a constant current of 0.3 mA, and the voltage was reduced to 80% voltage at the start of discharge. Ended with. The discharge capacity was measured from the discharge amount at this time, and the discharge capacity was divided by the positive electrode area to calculate the positive electrode capacity A (mAh / cm ² ).

（ｊ）負極容量の測定
　上記（ｈ）のリチウム極と負極の対からなるテストセルを用いて、充電（Ｌｉを炭素材にドープする過程）を０．３ｍＡ定電流で行い、０Ｖに達した後は、０Ｖ定電圧充電で行い、電流が０．０３ｍＡに減衰した時点を充電終了とした。次いで、放電（Ｌｉを炭素材から脱ドープする過程）を０．３ｍＡ定電流で行い、１．５Ｖに達するまで放電した。このときの放電量から放電容量を測定し、当該放電容量を負極電極面積で除して、負極容量Ｂ（ｍＡｈ／ｃｍ^２）を算出した。これにより容量比Ａ／Ｂを算出した。 (J) Measurement of negative electrode capacity Using the test cell comprising the lithium electrode and negative electrode pair in (h) above, charging (a process of doping Li into a carbon material) was performed at a constant current of 0.3 mA and reached 0 V. Thereafter, charging was performed at a constant voltage of 0 V, and charging was terminated when the current was attenuated to 0.03 mA. Next, discharge (a process of dedoping Li from the carbon material) was performed at a constant current of 0.3 mA and discharged until 1.5 V was reached. The discharge capacity was measured from the discharge amount at this time, and the discharge capacity was divided by the negative electrode area to calculate the negative electrode capacity B (mAh / cm ² ). Thereby, the capacity ratio A / B was calculated.

　（実施例２～７）
　実施例１と同様にＮＣＭ正極を用いた。負極活物質には、等方性ピッチを原料として不融化度を変えた前駆体を作成し、前駆体を粉砕、熱処理を行った非晶質炭素を用いた。正極厚み、負極厚みを変更させて、実施例１と同様の作製条件により、ＮＣＭの正極および炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Examples 2 to 7)
An NCM positive electrode was used in the same manner as in Example 1. As the negative electrode active material, a precursor having a different infusibility was prepared using isotropic pitch as a raw material, and the precursor was pulverized and subjected to heat treatment. A test cell and a full cell having an NCM positive electrode and a carbonaceous material negative electrode were produced under the same production conditions as in Example 1 by changing the thickness of the positive electrode and the thickness of the negative electrode, and the same evaluation items were measured.

（実施例８）
　実施例５で作成した負極を用い、正極活物質として、コバルト酸リチウム複合酸化物（ＬｉＣｏＯ_２）（ＬＣＯ）を用い、正極厚みを変えたこと以外は、実施例５と同様の作製条件により、ＬＣＯの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Example 8)
Using the negative electrode created in Example 5, using lithium cobalt oxide composite oxide (LiCoO ₂ ) (LCO) as the positive electrode active material, and changing the positive electrode thickness, the same production conditions as in Example 5, A test cell and a full cell having a positive electrode of LCO and a negative electrode of a carbonaceous material were produced, and the same evaluation items were measured.

（実施例９）
　実施例５で作成した負極を用い、正極活物質として、リン酸鉄リチウム（ＬｉＦｅＰＯ_４）（ＬＦＰ）を用い、正極厚み、負極厚みを変えたこと以外は、実施例５と同様の作製条件により、ＬＦＰの正極と炭素質材料の負極を備えたテストセル、フルセルを作製した。フルセルの充電時の定電圧を４．２Ｖから３．６Ｖに、充電上限電圧を３．６Ｖに、また、放電終止電圧を２．０Ｖに変更した以外は、実施例１（ＮＣＭ正極）の場合と同様の条件で充放電試験を行い、所定の評価項目を測定した。 Example 9
Except that the negative electrode prepared in Example 5 was used, lithium iron phosphate (LiFePO ₄ ) (LFP) was used as the positive electrode active material, and the positive electrode thickness and the negative electrode thickness were changed, the production conditions were the same as in Example 5. A test cell and a full cell having a positive electrode of LFP and a negative electrode of a carbonaceous material were prepared. In the case of Example 1 (NCM positive electrode) except that the constant voltage during full cell charging was changed from 4.2 V to 3.6 V, the upper limit voltage for charging was changed to 3.6 V, and the discharge end voltage was changed to 2.0 V A charge / discharge test was performed under the same conditions as above, and predetermined evaluation items were measured.

（実施例１０）
　実施例５で作成した負極を用い、正極活物質として、スピネル型マンガン酸リチウム複合酸化物（ＬｉＭｎ_２Ｏ_４）（ＬＭＯ）を用い、正極厚みを変えたこと以外は、実施例５と同様の作製条件により、ＬＭＯの正極と炭素質材料の負極を備えたテストセル、フルセルを作製した。フルセルの充電時の定電圧を４．２Ｖから４．１５Ｖに、充電上限電圧を４．１５Ｖに変更した以外は、実施例１（ＮＣＭ正極）の場合と同様の条件で充放電試験を行い、所定の評価項目を測定した。 (Example 10)
Example 5 is the same as Example 5 except that the negative electrode prepared in Example 5 is used, spinel-type lithium manganate composite oxide (LiMn ₂ O ₄ ) (LMO) is used as the positive electrode active material, and the positive electrode thickness is changed. A test cell and a full cell having a positive electrode of LMO and a negative electrode of a carbonaceous material were prepared according to the production conditions. A charge / discharge test was performed under the same conditions as in Example 1 (NCM positive electrode) except that the constant voltage during charging of the full cell was changed from 4.2 V to 4.15 V, and the charge upper limit voltage was changed to 4.15 V. Predetermined evaluation items were measured.

（実施例１１）
　市場で入手した、石炭コークスを原料とした易黒鉛化性炭素を用い、正極厚み、負極厚みを変更させたこと以外は実施例１と同様の作製条件により、ＮＣＭの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Example 11)
The NCM positive electrode and the negative electrode of the carbonaceous material were obtained under the same production conditions as in Example 1 except that graphitizable carbon made from coal coke as a raw material was used and the positive electrode thickness and negative electrode thickness were changed. A test cell and a full cell were prepared, and the same evaluation items were measured.

（比較例１）
　負極活物質には、等方性ピッチを原料として不融化度を変えた前駆体を作成し、前駆体を粉砕、熱処理を行った非晶質炭素を用いた。正極厚み、負極厚みを変更させたこと以外は実施例１と同様の作製条件により、ＮＣＭの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Comparative Example 1)
As the negative electrode active material, a precursor having a different infusibility was prepared using isotropic pitch as a raw material, and the precursor was pulverized and subjected to heat treatment. A test cell and a full cell having an NCM positive electrode and a carbonaceous material negative electrode were produced under the same production conditions as in Example 1 except that the positive electrode thickness and the negative electrode thickness were changed, and the same evaluation items were measured.

（比較例２）
　実施例５と同じ非晶質炭素を用い、正極厚み、負極厚みを変更させたこと以外は実施例１と同様の作製条件により、ＮＣＭの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Comparative Example 2)
A test cell comprising a NCM positive electrode and a carbonaceous material negative electrode under the same production conditions as in Example 1 except that the same amorphous carbon as in Example 5 was used and the thickness of the positive electrode and the thickness of the negative electrode were changed. The same evaluation items were measured.

（比較例３）
　実施例５と同じ非晶質炭素を用い、負極厚みを変更させたこと以外は実施例１０と同様の作製条件により、ＬＭＯの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、実施例１０と同様の条件で同様の評価項目を測定した。 (Comparative Example 3)
A test cell and a full cell having a positive electrode of LMO and a negative electrode of a carbonaceous material were prepared under the same production conditions as in Example 10 except that the same amorphous carbon as in Example 5 was used and the thickness of the negative electrode was changed. The same evaluation items were measured under the same conditions as in Example 10.

（比較例４）
　市場で入手した人造黒鉛を用い、正極厚み、負極厚みを変更させたこと以外は実施例１と同様の作製条件により、ＮＣＭの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Comparative Example 4)
A test cell and a full cell having an NCM positive electrode and a carbonaceous material negative electrode were prepared under the same production conditions as in Example 1 except that the thickness of the positive electrode and the thickness of the negative electrode were changed using artificial graphite obtained on the market. The same evaluation items were measured.

（比較例５）
　等方性ピッチを原料として熱処理を行った難黒鉛化性炭素を用い、正極厚み、負極厚みを変更させたこと以外は実施例１と同様の作製条件により、ＮＣＭの正極と炭素質材料の負極を備えたテストセル、フルセルを作製し、同様の評価項目を測定した。 (Comparative Example 5)
An NCM positive electrode and a carbonaceous material negative electrode were prepared under the same production conditions as in Example 1 except that non-graphitizable carbon subjected to heat treatment using isotropic pitch as a raw material was used and the thickness of the positive electrode and the thickness of the negative electrode were changed. A test cell and a full cell were prepared, and the same evaluation items were measured.

　実施例および比較例の測定した結果を表１に示す。入力密度、体積当たりの容量は実施例１の値で規格化した． Table 1 shows the measurement results of Examples and Comparative Examples. The input density and the capacity per volume were normalized with the values in Example 1.

　実施例１～１１は、負極活物質に真密度（ρ_Ｂｔ）が１．７０～２．２０ｇ／ｃｍ^３の範囲で、正極容量と負極容量との比（Ａ／Ｂ）が０．５～０．９の範囲にあり、正極容量Ａが３．０ｍＡｈ／ｃｍ^２以下の電池である。いずれも体積当たりの入力密度比が高く、体積当たりの容量が高い性能を示した。
　それに対し、比較例１は、負極活物質の炭素質材料の真密度（ρ_Ｂｔ）が１．７０ｇ／ｃｍ^３より低いため、体積当たりの容量が低かった。比較例２は、正極容量Ａが３．０ｍＡｈ／ｃｍ^２を超えるため、体積当たり入力密度比および体積当たりの容量が低かった。比較例３は、容量比Ａ／Ｂが０．５未満であるため、体積当たり入力密度および体積当たりの容量が低かった。比較例４は、負極活物質の炭素質材料の真密度（ρ_Ｂｔ）が２．２０ｇ／ｃｍ^３を上回り、ｄ_００２が０．３４２ｎｍを下回るため、体積当たりの入力密度が低かった。比較例５は、負極活物質の炭素質材料の真密度（ρ_Ｂｔ）が１．７０ｇ／ｃｍ^３を下回り、ｄ_００２が０．３７５ｎｍを上回るため、体積当たり入力密度比および体積当たりの容量が低かった。 In Examples 1 to 11, the negative electrode active material has a true density (ρ _Bt ) in the range of 1.70 to 2.20 g / cm ³ , and the ratio of positive electrode capacity to negative electrode capacity (A / B) is 0.5 to The battery has a positive electrode capacity A of 3.0 mAh / cm ² or less in a range of 0.9. In either case, the input density ratio per volume was high and the capacity per volume was high.
On the other hand, in Comparative Example 1, since the true density (ρ _Bt ) of the carbonaceous material of the negative electrode active material was lower than 1.70 g / cm ³ , the capacity per volume was low. In Comparative Example 2, since the positive electrode capacity A exceeded 3.0 mAh / cm ² , the input density ratio per volume and the capacity per volume were low. In Comparative Example 3, since the capacity ratio A / B was less than 0.5, the input density per volume and the capacity per volume were low. In Comparative Example 4, since the true density (ρ _Bt ) of the carbonaceous material of the negative electrode active material exceeded 2.20 g / cm ³ and d ₀₀₂ was less than 0.342 nm, the input density per volume was low. In Comparative Example 5, since the true density (ρ _Bt ) of the carbonaceous material of the negative electrode active material is less than 1.70 g / cm ³ and d ₀₀₂ is more than 0.375 nm, the input density ratio per volume and the capacity per volume are It was low.

　また、実施例において負極活物質層の厚みが４５μｍ以下であること、あるいは平均粒子径（Ｄｖ_５０）が４．５μｍ以下であると、特に入出力特性およびサイクル特性が良好であった。比較例１は、負極活物質層の厚みが４５μｍ以下であるが、負極活物質の炭素質材料の真密度（ρ_Ｂｔ）が１．７０ｇ／ｃｍ^３を下回るため体積当たりの容量が低下した。比較例２～５は、平均粒子径が４．５μ以下であるが、正極容量Ａが３．０ｍＡｈ／ｃｍ^２を超えるため、あるいは、正極容量と負極容量との比（Ａ／Ｂ）が本発明の範囲外であるため、あるいは、負極活物質の真密度（ρ_Ｂｔ）が本発明の範囲外であるため、体積当たりの入力密度が低下した。 In the examples, when the thickness of the negative electrode active material layer was 45 μm or less, or when the average particle diameter (Dv ₅₀ ) was 4.5 μm or less, the input / output characteristics and the cycle characteristics were particularly good. In Comparative Example 1, the negative electrode active material layer had a thickness of 45 μm or less. However, since the true density (ρ _Bt ) of the carbonaceous material of the negative electrode active material was less than 1.70 g / cm ³ , the capacity per volume decreased. In Comparative Examples 2 to 5, the average particle diameter is 4.5 μm or less, but the positive electrode capacity A exceeds 3.0 mAh / cm ² , or the ratio (A / B) of the positive electrode capacity to the negative electrode capacity is Since it is out of the scope of the invention, or because the true density (ρ _Bt ) of the negative electrode active material is outside the scope of the present invention, the input density per volume decreased.

　このように、本発明の構成を備えた実施例１～１１は、優れた入力密度を維持しつつ、大きな体積当たりの容量を実現できることを確認できた。 Thus, it was confirmed that Examples 1 to 11 having the configuration of the present invention can realize a large capacity per volume while maintaining an excellent input density.

Claims (4)

1. 　リチウムを含む遷移金属複合酸化物からなる正極活物質を含む正極と、炭素質材料を含む負極活物質を含む負極と、非水電解質とを備える非水電解質二次電池において、正極容量が３．０ｍＡｈ／ｃｍ^２以下（対極をＬｉ金属としたときの容量）であり、ブタノール法により求めた前記炭素質材料の真密度が１．７０～２．２０ｇ／ｃｍ^３であり、対向する正極容量Ａと負極容量Ｂの比（Ａ／Ｂ）が０．５～０．９であることを特徴とする非水電解質二次電池。 2. A nonaqueous electrolyte secondary battery comprising a positive electrode including a positive electrode active material made of a transition metal composite oxide containing lithium, a negative electrode including a negative electrode active material including a carbonaceous material, and a nonaqueous electrolyte. 0 mAh / cm ² or less (capacity when the counter electrode is Li metal), the true density of the carbonaceous material determined by the butanol method is 1.70 to 2.20 g / cm ³ , And a negative electrode capacity B ratio (A / B) of 0.5 to 0.9.
2. 前記負極における炭素質材料の、Ｘ線回折測定により求められる００２面の平均層面間隔（ｄ_００２）が０．３４２ｎｍ～０．３７５ｎｍであることを特徴とする請求項１に記載の非水電解質二次電池。 2. The non-aqueous electrolyte according to claim 1, wherein the carbonaceous material in the negative electrode has an average layer spacing (d ₀₀₂ ) of 002 planes determined by X-ray diffraction measurement of 0.342 nm to 0.375 nm. Next battery.
3. 　前記負極における負極活物質層の厚みが４５μｍ以下であることを特徴とする請求項１または２に記載の非水電解質二次電池。 The nonaqueous electrolyte secondary battery according to claim 1 or 2, wherein a thickness of the negative electrode active material layer in the negative electrode is 45 µm or less.
4. 　前記炭素質材料は、平均粒子径（Ｄｖ_５０）が４．５μｍ以下であることを特徴とする請求項３に記載の非水電解質二次電池。 The non-aqueous electrolyte secondary battery according to claim 3, wherein the carbonaceous material has an average particle diameter (Dv ₅₀ ) of 4.5 μm or less.

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