JP2011134535A - Positive electrode for lithium secondary battery, and method for manufacturing the same - Google Patents

Positive electrode for lithium secondary battery, and method for manufacturing the same Download PDF

Info

Publication number
JP2011134535A
JP2011134535A JP2009291809A JP2009291809A JP2011134535A JP 2011134535 A JP2011134535 A JP 2011134535A JP 2009291809 A JP2009291809 A JP 2009291809A JP 2009291809 A JP2009291809 A JP 2009291809A JP 2011134535 A JP2011134535 A JP 2011134535A
Authority
JP
Japan
Prior art keywords
positive electrode
active material
electrode active
conductive agent
comparative example
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2009291809A
Other languages
Japanese (ja)
Inventor
Kazuhiro Okamura
一広 岡村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Corp
Original Assignee
Panasonic Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Panasonic Corp filed Critical Panasonic Corp
Priority to JP2009291809A priority Critical patent/JP2011134535A/en
Publication of JP2011134535A publication Critical patent/JP2011134535A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode for a lithium secondary battery in which a positive electrode active material and a conductive agent are highly filled in a positive electrode mixture layer, and method for manufacturing the same. <P>SOLUTION: As the positive electrode active material and the conductive agent in order to form the positive electrode mixture layer, the conductive agent is contained by 0.5 to 4 pts.mass against the positive electrode active material 100 pts.mass, and out of particle size distribution cumulative curve of cumulative undersize percentage of a volumetric reference against a common logarithm value of a particle diameter (μm) of their mixture, a combination in which a correlation coefficient R of a primary regression line within a range of the cumulative undersize percentage of 0 to 30% becomes 0.94 or more is used. By rolling a coating film of the positive electrode mixture layer to include this combination and adjusting a volumetric ratio of the positive electrode active material to 0.8 or more, the positive electrode for the lithium secondary in which the positive electrode active material and the conductive agent are highly filled into the positive electrode mixture layer is obtained. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、リチウム二次電池用正極とその製造方法に関し、詳しくは、リチウム二次電池用正極の正極合剤層における正極活物質および導電剤の充填密度の改良に関する。   The present invention relates to a positive electrode for a lithium secondary battery and a method for producing the same, and more particularly, to an improvement in packing density of a positive electrode active material and a conductive agent in a positive electrode mixture layer of a positive electrode for a lithium secondary battery.

リチウムイオン電池を始めとするリチウム二次電池は、パーソナルコンピュータ、携帯電話、デジタルカメラ、カムコーダなどの携帯型電子機器に用いられる電源として、広く普及している。また、リチウム二次電池は、ハイブリッド自動車や電気自動車に用いられる電源としての需要の拡大も予想されている。このため、リチウム二次電池は、とりわけ高容量化および高エネルギー密度化の観点から検討が重ねられている。   Lithium secondary batteries such as lithium ion batteries are widely used as power sources used in portable electronic devices such as personal computers, mobile phones, digital cameras, and camcorders. In addition, lithium secondary batteries are expected to increase in demand as power sources used in hybrid vehicles and electric vehicles. For this reason, lithium secondary batteries have been studied in particular from the viewpoint of higher capacity and higher energy density.

リチウム二次電池の正極は、正極集電体とその表面に形成された正極合剤層とを備えており、正極合剤層は、正極活物質および導電剤を含有している。このようなリチウム二次電池の高容量化および高エネルギー密度化を図るには、正極合剤層における正極活物質および導電剤の充填密度を高くすることが望まれる。   The positive electrode of the lithium secondary battery includes a positive electrode current collector and a positive electrode mixture layer formed on the surface thereof, and the positive electrode mixture layer contains a positive electrode active material and a conductive agent. In order to increase the capacity and energy density of such a lithium secondary battery, it is desired to increase the packing density of the positive electrode active material and the conductive agent in the positive electrode mixture layer.

特許文献１は、リチウム電池における炭素からなる電極を形成するにあたって、平均粒径が異なる２種の炭素粒子を混合することを提案している。この提案は、平均粒径が大きい炭素粒子間の空隙に平均粒径が小さい炭素粒子を充填させて、これにより、空隙を減少させ、炭素粒子の充填密度を高くすることを意図している。   Patent Document 1 proposes mixing two kinds of carbon particles having different average particle diameters when forming an electrode made of carbon in a lithium battery. This proposal is intended to fill the voids between carbon particles having a large average particle size with carbon particles having a small average particle size, thereby reducing the voids and increasing the packing density of the carbon particles.

特開平４−８２１７２号公報JP-A-4-82172

特許文献１に開示されたように、平均粒径が異なる２種の炭素粒子を単に混合しただけでは、電極の内部に炭素粒子が充填されていない空隙部分が多く残存してしまう。このことは、正極合剤層の作製においても同様であって、体積基準の平均粒径や粒度分布が互いに異なる正極活物質と導電剤とを単に混合しただけでは、正極合剤層中に正極活物質および導電剤が存在していない空隙部分が多く残存するため、正極活物質および導電剤の充填密度を十分に高くすることができない。   As disclosed in Patent Document 1, if two types of carbon particles having different average particle diameters are simply mixed, many void portions that are not filled with carbon particles remain inside the electrode. This also applies to the production of the positive electrode mixture layer, and the positive electrode active material and the conductive agent having different volume-based average particle diameters and particle size distributions are simply mixed, and the positive electrode mixture layer contains the positive electrode mixture layer. Since many void portions in which the active material and the conductive agent do not exist remain, the packing density of the positive electrode active material and the conductive agent cannot be sufficiently increased.

本発明は、正極合剤層中に正極活物質および導電剤を高充填されたリチウム二次電池用正極とその製造方法を提供することを目的とする。   An object of this invention is to provide the positive electrode for lithium secondary batteries with which the positive mix layer was highly filled with the positive electrode active material and the electrically conductive agent, and its manufacturing method.

本発明の一局面のリチウム二次電池用正極は、リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤層を備えたリチウム二次電池用正極であって、前記正極合剤層における前記正極活物質の体積比率が０．８以上であり、前記正極活物質および前記導電剤は、前記正極活物質１００質量部に対して前記導電剤を０．５〜４質量部含有し、かつ、それらの混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率で表される粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるような組み合わせで前記正極合剤層に含まれていることを特徴とする。   A positive electrode for a lithium secondary battery according to one aspect of the present invention includes a positive electrode active material capable of occluding and releasing lithium ions, a conductive agent, and a positive electrode mixture layer including a binder. The volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more, and the positive electrode active material and the conductive agent are zero in the conductive agent with respect to 100 parts by mass of the positive electrode active material. Among the particle size distribution integrated curves containing 5 to 4 parts by mass and represented by the volume-based integrated sieving percentage with respect to the common logarithm of the particle size (μm) of the mixture, the integrated sieving percentage is 0 to The positive electrode mixture layer is included in such a combination that the correlation coefficient R of the linear regression line in the range of 30% is 0.94 or more.

本発明の他の一局面のリチウム二次電池用正極の製造方法は、リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤ペーストを正極集電体に塗工して塗膜を形成する塗膜形成工程と、前記塗膜を圧延することにより正極合剤層を形成する圧延工程と、を備え、前記正極活物質および前記導電剤として、前記正極活物質１００質量部に対して前記導電剤を０．５〜４質量部含有し、かつ、それらの混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率の粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるような、正極活物質と導電剤との組み合わせを用い、前記圧延工程において、前記正極合剤層における前記正極活物質の体積比率が０．８以上となるように前記塗膜を圧延することを特徴とする。   According to another aspect of the present invention, there is provided a method for producing a positive electrode for a lithium secondary battery, wherein a positive electrode mixture paste containing a positive electrode active material capable of occluding and releasing lithium ions, a conductive agent, and a binder is used as a positive electrode current collector. A coating film forming step of forming a coating film by coating on the body, and a rolling step of forming a positive electrode mixture layer by rolling the coating film, and as the positive electrode active material and the conductive agent, The conductive agent is contained in an amount of 0.5 to 4 parts by mass with respect to 100 parts by mass of the positive electrode active material, and the volume-based cumulative particle size distribution is integrated with respect to the common logarithm of the particle size (μm) of the mixture. In the rolling process, using a combination of a positive electrode active material and a conductive agent such that the correlation coefficient R of the linear regression line in the range of 0 to 30% in the range of the cumulative sieve is 0.94 or higher among the curves. The positive electrode active in the positive electrode mixture layer Volume ratio of quality characterized by rolling the paint film so that 0.8 or more.

本発明によれば、正極合剤層中に正極活物質および導電剤が存在していない空隙部分を減少させることができる。それゆえ、正極合剤層における正極活物質および導電剤の充填密度を向上させることができ、容量が極めて大きなリチウム二次電池用正極を製造することができる。また、こうして得られた正極を用いることにより、リチウム二次電池の高容量化および高エネルギー密度化を図ることができる。   According to the present invention, it is possible to reduce void portions where the positive electrode active material and the conductive agent are not present in the positive electrode mixture layer. Therefore, the packing density of the positive electrode active material and the conductive agent in the positive electrode mixture layer can be improved, and a positive electrode for a lithium secondary battery having an extremely large capacity can be manufactured. Further, by using the positive electrode thus obtained, it is possible to increase the capacity and energy density of the lithium secondary battery.

本実施形態の正極活物質と導電剤との混合物における体積基準の粒度分布の一例を示すグラフである。It is a graph which shows an example of the volume reference | standard particle size distribution in the mixture of the positive electrode active material of this embodiment, and a electrically conductive agent. 図１に示すグラフのうち、積算ふるい下百分率が０％以上３０％以下の範囲における粒度分布曲線と、粒径の常用対数値と積算ふるい下百分率の値とから求められる一次回帰直線の一例を示すグラフである。In the graph shown in FIG. 1, an example of a linear regression line obtained from a particle size distribution curve in a range where the percentage under integrated sieving is 0% or more and 30% or less, a common logarithmic value of particle size, and a value of percentage under integrated sieving. It is a graph to show. 体積基準の粒径が対数正規分布を示し、かつ平均粒径が互いに異なる２種の粒子の混合物における粒度分布と、ふるい下百分率の積算曲線とを示すグラフである。It is a graph which shows the particle size distribution in the mixture of 2 types of particle | grains from which a volume-based particle size shows logarithmic normal distribution, and an average particle size mutually differ, and the integration curve of the percentage under sieving. 円筒型リチウムイオン電池の一例を示す縦断面図である。It is a longitudinal section showing an example of a cylindrical lithium ion battery.

＜リチウム二次電池用正極＞
はじめに、本発明に係るリチウム二次電池用正極の好ましい実施形態について、詳しく説明する。
本実施形態のリチウム二次電池用正極は、リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤層を備える。 <Positive electrode for lithium secondary battery>
First, a preferred embodiment of the positive electrode for a lithium secondary battery according to the present invention will be described in detail.
The positive electrode for a lithium secondary battery according to this embodiment includes a positive electrode mixture layer including a positive electrode active material capable of inserting and extracting lithium ions, a conductive agent, and a binder.

また、本実施形態のリチウム二次電池用正極において、正極合剤層における正極活物質の体積比率が０．８以上である。
さらに、正極活物質および導電剤は、正極活物質１００質量部に対して導電剤を０．５〜４質量部含有し、かつ、それらの混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率で表される粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるような組み合わせで正極合剤層に含まれている。 Moreover, in the positive electrode for lithium secondary batteries of this embodiment, the volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more.
Furthermore, the positive electrode active material and the conductive agent contain 0.5 to 4 parts by mass of the conductive agent with respect to 100 parts by mass of the positive electrode active material, and are based on the volume of the common logarithm of the particle size (μm) of the mixture. Of the particle size distribution expressed by the percentage under the cumulative sieve of the positive electrode mixture in such a combination that the correlation coefficient R of the primary regression line in the range of the percentage under the cumulative sieve of 0 to 30% is 0.94 or more Included in the layer.

正極活物質としては、リチウムイオンを吸蔵および放出可能な材料として従来からリチウム二次電池に用いられているものを特に限定なく用いることができる。その具体例としては、リチウム遷移金属複合酸化物、遷移金属ポリアニオン化合物などが挙げられ、これらの中でも特に、リチウム遷移金属複合酸化物が好適である。   As the positive electrode active material, those conventionally used in lithium secondary batteries as materials capable of inserting and extracting lithium ions can be used without particular limitation. Specific examples thereof include lithium transition metal composite oxides and transition metal polyanion compounds. Among these, lithium transition metal composite oxides are particularly preferable.

リチウム遷移金属複合酸化物としては、ニッケル酸リチウム（ＬｉＮｉＯ2）、コバルト酸リチウム（ＬｉＣｏＯ2）、マンガン酸リチウム（ＬｉＭｎ2Ｏ4）、およびこれらの変性体が挙げられる。変性体としては、ＬｉＮｉＯ2、ＬｉＣｏＯ2およびＬｉＭｎ2Ｏ4におけるＣｏ、ＮｉまたはＭｎの一部を他の元素で置換したものが挙げられる。他の元素としては、遷移金属（Ｎｉ、Ｃｏ、Ｍｎ、Ｆｅ、Ｃｒ、Ｔｉ、Ｚｒなど）、Ａｌ、Ｃｕ、Ｚｎ、Ｍｇ、アルカリ土類金属（Ｃａなど）が挙げられる。 Examples of the lithium transition metal composite oxide include lithium nickelate (LiNiO 2 ), lithium cobaltate (LiCoO 2 ), lithium manganate (LiMn 2 O 4 ), and modified products thereof. The modified products include those obtained by substituting Co in LiNiO 2, LiCoO 2 and LiMn 2 O 4, a part of Ni or Mn with other elements. Examples of other elements include transition metals (Ni, Co, Mn, Fe, Cr, Ti, Zr, etc.), Al, Cu, Zn, Mg, and alkaline earth metals (Ca, etc.).

遷移金属ポリアニオン化合物としては、ナシコン構造またはオリビン構造を有するリン酸化合物、硫酸化合物などが挙げられる。遷移金属としては、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉなどが挙げられる。
これら正極活物質は、１種のみを単独で、または２種以上を組み合わせて用いることができる。また、正極活物質は、上記例示の化合物の中でも特に、ＬｉＮｉＯ2およびその変性体が好適である。 Examples of the transition metal polyanion compound include a phosphate compound having a NASICON structure or an olivine structure, and a sulfate compound. Examples of the transition metal include Mn, Fe, Co, Ni, and the like.
These positive electrode active materials can be used alone or in combination of two or more. As the positive electrode active material, LiNiO 2 and modified products thereof are particularly suitable among the compounds exemplified above.

導電剤は、正極活物質の導電性を補うために正極合剤層に含有される。このような導電剤としては、アセチレンブラック、ケッチェンブラック、ファーネスブラックなどの各種カーボンブラックや、黒鉛粒子といった炭素材料が挙げられる。導電剤は、１種のみを単独で、または２種以上を組み合わせて用いることができる。また、導電剤は、上記例示の化合物の中でも特に、導電性に優れたアセチレンブラックが好適である。   The conductive agent is contained in the positive electrode mixture layer in order to supplement the conductivity of the positive electrode active material. Examples of such a conductive agent include various carbon blacks such as acetylene black, ketjen black, and furnace black, and carbon materials such as graphite particles. Only one type of conductive agent can be used alone, or two or more types can be used in combination. The conductive agent is preferably acetylene black having excellent conductivity, among the compounds exemplified above.

正極活物質および導電剤は、必要に応じて粉砕および分級を施すことにより、あらかじめ粒度分布が異なる複数のサンプルとする。そして、これら複数のサンプルを、正極活物質１００質量部に対して導電剤が０．５〜４質量部の割合で含有されるように、かつ、混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率の粒度分布積算曲線において、積算ふるい下百分率の０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上となるように混合する。   The positive electrode active material and the conductive agent are pulverized and classified as necessary to obtain a plurality of samples having different particle size distributions in advance. And these some samples are contained with respect to the common logarithm value of the particle size (micrometer) of a mixture so that a electrically conductive agent may be contained in the ratio of 0.5-4 mass parts with respect to 100 mass parts of positive electrode active materials. In the particle size distribution integration curve of the volume-based cumulative sieve percentage, the linear regression line in the range of 0-30% of the integrated sieve percentage is mixed so that the correlation coefficient R is 0.94 or more.

一般に入手可能な正極活物質は、体積基準の平均粒径（体積平均粒径）が１０〜４０μｍ程度である。一方、一般に入手可能な導電剤は、体積平均粒径が概ね１０μｍを下回る。そこで、これに限定されないが、正極活物質と導電剤との混合物は、例えば下記の手順を経ることにより調製することができる。
まず、一般に入手可能な正極活物質のサンプルと、このような正極活物質に粉砕および分級を施して、粒径が主として１０μｍを下回るように調整されたサンプルとを準備する。粉砕および分級が施された正極活物質のサンプルは、体積基準の粒度分布が１種類のものに限定されず、粒度分布が互いに異なる２種以上のサンプルを調製することもできる。 Generally available positive electrode active materials have a volume-based average particle size (volume average particle size) of about 10 to 40 μm. On the other hand, generally available conductive agents have a volume average particle size of generally less than 10 μm. Therefore, although not limited thereto, the mixture of the positive electrode active material and the conductive agent can be prepared, for example, through the following procedure.
First, a sample of a generally available positive electrode active material and a sample in which such a positive electrode active material is pulverized and classified to have a particle size adjusted mainly below 10 μm are prepared. The sample of the positive electrode active material subjected to pulverization and classification is not limited to one having a volume-based particle size distribution, and two or more samples having different particle size distributions can also be prepared.

一方、一般に入手可能な導電剤のサンプルと、このような導電剤に粉砕および分級を施すことにより、体積基準の頻度分布において粒径が数μｍ程度にピークを有するようなサンプルとを準備する。
正極活物質と導電剤との混合物について上述の相関係数Ｒを所定の範囲に設定するには、積算ふるい下百分率が０〜３０％の範囲に相当するような粒径が小さい範囲において、正極活物質および導電剤の存在割合（頻度）が平均化されていることが好ましい。上記の粒径が小さい範囲としては、後述する図１に示す場合に、粒径が１５μｍ程度以下の範囲が相当する。そして、導電剤は、一般に正極活物質に比べて体積基準の平均粒径が小さいことから、小粒径でかつ互いに粒度分布が異なる複数種の導電剤のサンプルをあらかじめ準備しておき、これら導電剤のサンプルを用いて粒径が小さい範囲の導電剤の存在割合を調整することが、混合物の相関係数Ｒの調整を容易にするという観点から好ましい。 On the other hand, a sample of a conductive agent that is generally available and a sample having a particle size peak at about several μm in a volume-based frequency distribution are prepared by grinding and classifying such a conductive agent.
In order to set the above-mentioned correlation coefficient R in the predetermined range for the mixture of the positive electrode active material and the conductive agent, the positive electrode is used in a range where the particle size is small such that the percentage under integrated sieving corresponds to the range of 0 to 30%. It is preferable that the existence ratio (frequency) of the active material and the conductive agent is averaged. The range in which the particle size is small corresponds to a range in which the particle size is about 15 μm or less in the case shown in FIG. Since the conductive agent generally has a volume-based average particle size smaller than that of the positive electrode active material, samples of a plurality of types of conductive agents having a small particle size and different particle size distributions are prepared in advance. It is preferable from the viewpoint of facilitating the adjustment of the correlation coefficient R of the mixture to adjust the abundance ratio of the conductive agent having a small particle size using a sample of the agent.

こうして準備された正極活物質のサンプルと、導電剤のサンプルとを、適宜組み合わせて混合物を調製する。このときに、導電剤の含有割合を正極活物質１００質量部に対して０．５〜４質量部に調整する。また、混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率の粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるように、使用する正極活物質および導電剤のサンプルの粒度分布、各サンプル間の配合比率などを調整する。   A mixture is prepared by appropriately combining the sample of the positive electrode active material thus prepared and the sample of the conductive agent. At this time, the content rate of a electrically conductive agent is adjusted to 0.5-4 mass parts with respect to 100 mass parts of positive electrode active materials. In addition, the correlation coefficient R of the primary regression line in the range of the cumulative sieving percentage in the range of 0 to 30% of the volume-based cumulative sieving percentage particle size distribution curve with respect to the common logarithm of the particle size (μm) of the mixture is The particle size distribution of the positive electrode active material and the conductive agent sample to be used, the blending ratio between the samples, and the like are adjusted so as to be 0.94 or more.

なお、体積基準の粒度分布（頻度分布）がともに対数正規分布を示す、平均粒径が互いに異なる２種の粒子を混合した場合に、ｘ座標を体積基準の粒径の常用対数値とし、ｙ座標を頻度（存在比率）とした粒度分布は、図３に示すように、頻度分布が２峰性分布を示し、積算ふるい下粒度分布において２つのＳ字カーブが現れる。この図３のグラフについて、混合物の粒径の常用対数値と、積算ふるい下百分率との関係を直線回帰計算により求めると、積算ふるい下百分率が０〜３０％の範囲における相関係数Ｒは低い値を示す。   In addition, when two kinds of particles having different average particle diameters are mixed, both of which have a volume-based particle size distribution (frequency distribution) having a logarithmic normal distribution, the x coordinate is a common logarithmic value of the volume-based particle diameter, and y As shown in FIG. 3, the particle size distribution with the coordinates as frequency (existence ratio) shows a bimodal distribution, and two S-shaped curves appear in the integrated sieved particle size distribution. In the graph of FIG. 3, when the relationship between the common logarithm of the particle size of the mixture and the percentage under the integrated sieve is obtained by linear regression calculation, the correlation coefficient R in the range of the integrated sieve under percentage of 0 to 30% is low. Indicates the value.

これに対し、本実施形態における正極活物質と導電剤との混合物は、体積平均粒径が大きい粒子の間に体積平均粒径が小さい粒子が密に充填されている。一般的には、体積平均粒径が大きい正極活物質の粒子間に、体積平均粒径が小さい導電剤が充填された状態となる。このような混合物の粒度分布は、例えば図１に示すように、積算ふるい下百分率が０〜３０％の範囲に相当するような粒径が小さい範囲（粒径が概ね１５μｍ以下の範囲）において、正極活物質および導電剤の存在割合（頻度）が平均化されている。積算ふるい下百分率が０〜３０％の範囲を拡大した図２に示すように、この範囲におけるふるい下百分率の積算曲線と、その一次回帰直線とは、概ね一致しており、相関係数Ｒは０．９４以上（図１の場合、Ｒ＝０．９７）となる。   On the other hand, the mixture of the positive electrode active material and the conductive agent in the present embodiment is closely packed with particles having a small volume average particle size between particles having a large volume average particle size. Generally, a conductive agent having a small volume average particle size is filled between positive electrode active material particles having a large volume average particle size. The particle size distribution of such a mixture is, for example, as shown in FIG. 1, in a range where the particle size is small (the particle size is generally about 15 μm or less) corresponding to a range where the cumulative sieving percentage is 0 to 30%. The abundance ratio (frequency) of the positive electrode active material and the conductive agent is averaged. As shown in FIG. 2 in which the range of the percentage under the cumulative sieve is expanded from 0 to 30%, the cumulative curve of the percentage under the sieve in this range and the linear regression line thereof are almost the same, and the correlation coefficient R is 0.94 or more (in the case of FIG. 1, R = 0.97).

導電剤の含有量は、正極活物質１００質量部に対して０．５〜４質量部であり、好ましくは１〜３質量部である。導電剤の含有量を上記範囲に設定し、かつ、正極活物質および導電剤の混合物における上述の相関係数Ｒを上記範囲に設定することで、正極合剤層における正極活物質および導電剤の混合物の充填密度を高めることができる。特に、正極活物質の粒子同士が直接接触していない部分においても、正極活物質の粒子間に導電剤が密に充填されることから、正極合剤層内で電気の流れる経路を多く確保して、正極の容量を極めて大きなものとすることができる。   Content of a electrically conductive agent is 0.5-4 mass parts with respect to 100 mass parts of positive electrode active materials, Preferably it is 1-3 mass parts. By setting the content of the conductive agent in the above range and setting the above correlation coefficient R in the mixture of the positive electrode active material and the conductive agent in the above range, the positive electrode active material and the conductive agent in the positive electrode mixture layer The packing density of the mixture can be increased. In particular, even in the part where the positive electrode active material particles are not in direct contact with each other, the conductive agent is closely packed between the positive electrode active material particles, so that a large number of paths through which electricity flows in the positive electrode mixture layer can be secured. Thus, the capacity of the positive electrode can be made extremely large.

結着剤は、正極活物質および導電剤を正極集電体の表面に結着させるために配合される。このような結着剤としては、従来からリチウム二次電池に用いられているものを特に限定なく用いることができる。その具体例としては、ポリテトラフルオロエチレン（ＰＴＦＥ）、ＰＴＦＥの変性体、ポリフッ化ビニリデン（ＰＶＤＦ）、ＰＶＤＦの変性体、フッ素ゴムなどの含フッ素樹脂、ポリプロピレン、ポリエチレンなどの熱可塑性樹脂、変性アクリロニトリルゴム粒子（例えば、日本ゼオン（株）製の「ＢＭ−５００Ｂ（商品名）」）などが挙げられる。   The binder is blended to bind the positive electrode active material and the conductive agent to the surface of the positive electrode current collector. As such a binder, those conventionally used for lithium secondary batteries can be used without any particular limitation. Specific examples thereof include polytetrafluoroethylene (PTFE), modified PTFE, polyvinylidene fluoride (PVDF), modified PVDF, fluorine-containing resins such as fluororubber, thermoplastic resins such as polypropylene and polyethylene, and modified acrylonitrile. Examples thereof include rubber particles (for example, “BM-500B (trade name)” manufactured by Nippon Zeon Co., Ltd.).

ＰＴＦＥやＢＭ−５００Ｂを結着剤として用いる場合には、増粘剤を併用することが好ましい。増粘剤としては、カルボキシメチルセルロース（ＣＭＣ）、ポリエチレンオキシド、変性アクリロニトリルゴム（例えば、日本ゼオン（株）製の「ＢＭ−７２０Ｈ（商品名）」）などが挙げられる。   When PTFE or BM-500B is used as a binder, it is preferable to use a thickener together. Examples of the thickener include carboxymethyl cellulose (CMC), polyethylene oxide, and modified acrylonitrile rubber (for example, “BM-720H (trade name)” manufactured by Nippon Zeon Co., Ltd.).

正極合剤層は、必須成分としての正極活物質、導電剤および結着剤と、任意成分としての増粘剤とを含んでいる。また、正極合剤層は、その内部に、正極活物質および導電剤の混合物における粒子間の空隙部分も含んでいる。   The positive electrode mixture layer contains a positive electrode active material, a conductive agent, and a binder as essential components, and a thickener as an optional component. Further, the positive electrode mixture layer also includes void portions between particles in the mixture of the positive electrode active material and the conductive agent.

結着剤の含有量は特に限定されないが、正極活物質および導電剤を正極集電体の表面に結着させることができる範囲で、できるだけ少ない方が好ましい。結着剤の含有量を少なく設定することで、正極合剤層における正極活物質の体積比率をより一層高くすることができる。
本実施形態において、正極合剤層における正極活物質の体積比率は０．８以上であり、好ましくは０．８５以上である。正極活物質の体積比率を上記範囲に設定することで、正極活物質と導電剤とが密に充填されて、正極合剤層の内部に空隙部分が生じることを抑制することができる。 The content of the binder is not particularly limited, but is preferably as small as possible as long as the positive electrode active material and the conductive agent can be bound to the surface of the positive electrode current collector. By setting the content of the binder small, the volume ratio of the positive electrode active material in the positive electrode mixture layer can be further increased.
In the present embodiment, the volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more, preferably 0.85 or more. By setting the volume ratio of the positive electrode active material in the above range, it is possible to prevent the positive electrode active material and the conductive agent from being densely filled and to generate voids in the positive electrode mixture layer.

＜リチウム二次電池用正極の製造方法＞
次に、本発明に係るリチウム二次電池用正極の製造方法の好ましい実施形態について、詳しく説明する。
本実施形態のリチウム二次電池用正極の製造方法は、リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤ペーストを正極集電体に塗工して塗膜を形成する塗膜形成工程と、この塗膜形成工程で得られた塗膜を圧延することにより正極合剤層を形成する圧延工程と、を備える。 <Method for producing positive electrode for lithium secondary battery>
Next, a preferred embodiment of the method for producing a positive electrode for a lithium secondary battery according to the present invention will be described in detail.
The method for producing a positive electrode for a lithium secondary battery according to the present embodiment applies a positive electrode mixture paste containing a positive electrode active material capable of occluding and releasing lithium ions, a conductive agent, and a binder to a positive electrode current collector. A coating film forming process for forming a coating film, and a rolling process for forming a positive electrode mixture layer by rolling the coating film obtained in the coating film forming process.

また、本実施形態のリチウム二次電池用正極の製造方法においては、正極活物質および導電剤として、正極活物質１００質量部に対して導電剤を０．５〜４質量部含有し、かつ、それらの混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率の粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるような、正極活物質と導電剤との組み合わせを用いる。
さらに、圧延工程において、正極合剤層における正極活物質の体積比率が０．８以上となるように塗膜を圧延する。 Moreover, in the manufacturing method of the positive electrode for lithium secondary batteries of this embodiment, as a positive electrode active material and a electrically conductive agent, 0.5-4 mass parts of conductive agents are contained with respect to 100 mass parts of positive electrode active materials, and Among the particle size distribution integration curves of the volume-based cumulative sieve percentage relative to the common logarithm of the particle size (μm) of the mixture, the correlation coefficient R of the primary regression line in the range of the cumulative sieve percentage of 0-30% is A combination of a positive electrode active material and a conductive agent that is 0.94 or more is used.
Furthermore, in the rolling process, the coating film is rolled so that the volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more.

次に、塗膜形成工程について詳細に説明する。
塗膜形成工程では、まず、リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤ペーストを調製する。
正極活物質および導電剤としては、上述の混合物を用いる。結着剤としては、上述の成分を用いる。 Next, the coating film forming step will be described in detail.
In the coating film forming step, first, a positive electrode mixture paste including a positive electrode active material capable of inserting and extracting lithium ions, a conductive agent, and a binder is prepared.
The above-mentioned mixture is used as the positive electrode active material and the conductive agent. The above-described components are used as the binder.

正極合剤ペーストの調製に用いる分散媒としては、Ｎ−メチル−２−ピロリドン（ＮＭＰ）などの有機溶媒や、水などが挙げられる。正極合剤ペーストの経時安定性や分散性を向上させる観点から、界面活性剤などの添加剤を加えることができる。
正極合剤ペーストの調製方法は特に限定されず、従来公知の各種の方法を採用することができる。 Examples of the dispersion medium used for preparing the positive electrode mixture paste include organic solvents such as N-methyl-2-pyrrolidone (NMP), water, and the like. From the viewpoint of improving the temporal stability and dispersibility of the positive electrode mixture paste, additives such as a surfactant can be added.
The method for preparing the positive electrode mixture paste is not particularly limited, and various conventionally known methods can be employed.

次いで、こうして調製された正極合剤ペーストを正極集電体の表面に塗布し、乾燥させて成膜する。
正極集電体としては、例えばアルミニウムなどの正極電位で安定な金属の箔や、金属を表層に含むフィルムなどを用いることができる。なお、集電体の集電性をさらに向上させる観点から、表面に凹凸を設けたり、穿孔したりすることができる。 Next, the positive electrode mixture paste thus prepared is applied to the surface of the positive electrode current collector and dried to form a film.
As the positive electrode current collector, for example, a metal foil that is stable at a positive electrode potential such as aluminum, a film containing a metal in the surface layer, or the like can be used. In addition, from the viewpoint of further improving the current collecting property of the current collector, the surface can be provided with unevenness or can be perforated.

次に、圧延工程について詳細に説明する。
圧延工程では、上記塗膜形成工程で得られた塗膜を、ローラなどによって圧延することにより、正極合剤層を形成する。塗膜の圧延方法は特に限定されず、従来公知の各種の方法を採用することができる。 Next, the rolling process will be described in detail.
In the rolling step, the positive electrode mixture layer is formed by rolling the coating film obtained in the coating film forming step with a roller or the like. The rolling method of a coating film is not specifically limited, Various conventionally well-known methods are employable.

塗膜の圧延の程度は、正極合剤層における正極活物質の体積比率が０．８以上となるように調整する。正極活物質の体積比率は、上記範囲の中でも特に、０．８５以上が好ましい。正極合剤層に占める正極活物質の体積比率を上記範囲に設定することで、正極合剤層の空隙を減らし、正極活物質や導電剤の粒子間の接触を増やすことができる。
塗膜の圧延条件は特に限定されないが、圧延時の圧力は１０〜１００ＭＰａであることが好ましい。 The degree of rolling of the coating film is adjusted so that the volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more. The volume ratio of the positive electrode active material is particularly preferably 0.85 or more in the above range. By setting the volume ratio of the positive electrode active material in the positive electrode mixture layer within the above range, the voids of the positive electrode mixture layer can be reduced, and the contact between the particles of the positive electrode active material and the conductive agent can be increased.
Although the rolling conditions of a coating film are not specifically limited, It is preferable that the pressure at the time of rolling is 10-100 MPa.

本実施形態の製造方法によれば、塗膜を圧延することにより、正極合剤層における正極活物質の体積比率を向上させることができる。しかも、正極活物質および導電剤の混合物について、その粒度分布が上述のように調整されていることから、圧延後の正極活物質内において、正極活物質と導電剤とを密に充填させることができる。その結果、本実施形態の製造方法を用いることによって、正極の容量を極めて大きくすることができる。   According to the manufacturing method of this embodiment, the volume ratio of the positive electrode active material in a positive mix layer can be improved by rolling a coating film. Moreover, since the particle size distribution of the mixture of the positive electrode active material and the conductive agent is adjusted as described above, the positive electrode active material and the conductive agent can be closely packed in the positive electrode active material after rolling. it can. As a result, the capacity of the positive electrode can be extremely increased by using the manufacturing method of the present embodiment.

こうして得られたリチウム二次電池用正極は、負極および多孔質絶縁層とともに電極群を構成し、この電極群を非水電解質とともに電池ケースに収容することによって、リチウム二次電池を得ることができる。   The thus obtained positive electrode for a lithium secondary battery constitutes an electrode group together with the negative electrode and the porous insulating layer, and a lithium secondary battery can be obtained by accommodating this electrode group in a battery case together with a nonaqueous electrolyte. .

具体的に、リチウム二次電池は、以下の方法で作製することができる。まず、正極と負極とを、多孔質絶縁層を介して巻回して電極群を作製し、電池ケースに収容する。正極集電体と正極端子とを、正極リードで電気的に接続する。負極集電体と負極端子とを、負極リードで電気的に接続する。その後、電極群に非水電解質を接触させ、封口板で電池ケースを密閉することで、リチウム二次電池が得られる。
リチウム二次電池の形状は特に限定されない。例えば、円筒型、角型ならびにシート型などの公知の構造を用いることができる。 Specifically, the lithium secondary battery can be produced by the following method. First, a positive electrode and a negative electrode are wound through a porous insulating layer to produce an electrode group, and accommodated in a battery case. The positive electrode current collector and the positive electrode terminal are electrically connected by a positive electrode lead. The negative electrode current collector and the negative electrode terminal are electrically connected by a negative electrode lead. Thereafter, a non-aqueous electrolyte is brought into contact with the electrode group, and the battery case is sealed with a sealing plate, whereby a lithium secondary battery is obtained.
The shape of the lithium secondary battery is not particularly limited. For example, known structures such as a cylindrical shape, a square shape, and a sheet shape can be used.

負極は、リチウムイオンを吸蔵、放出可能な負極活物質を必須成分として含み、結着剤を任意成分として含む。
負極活物質は特に限定されず、例えば、各種天然黒鉛、各種人造黒鉛、石油コークス、炭素繊維、有機高分子焼成物、カーボンナノチューブ、カーボンナノホーンなどの炭素材料、酸化物、シリコン含有複合材料、スズ含有複合材料、各種金属、合金材料など、公知のものを用いることができる。 The negative electrode includes a negative electrode active material capable of occluding and releasing lithium ions as an essential component, and a binder as an optional component.
The negative electrode active material is not particularly limited. For example, various natural graphites, various artificial graphites, petroleum coke, carbon fibers, organic polymer fired products, carbon nanotubes, carbon nanohorns and other carbon materials, oxides, silicon-containing composite materials, tin Known materials such as a composite material, various metals, and alloy materials can be used.

負極の形成に用いられる結着剤は特に限定されないが、少量で十分な結着性が得られる観点からゴム粒子を用いることが好ましい。特に、スチレン単位およびブタジエン単位を含むゴム粒子を用いることが好ましい。このような結着剤としては、例えばスチレン−ブタジエン共重合体（ＳＢＲ）、ＳＢＲの変性体などが挙げられる。負極結着剤としてゴム粒子を用いる場合、増粘剤を併用することが好ましい。増粘剤としては、例えば、水溶性高分子を含むものが挙げられ、水溶性高分子としては、セルロース系樹脂が好ましく、特にＣＭＣが好ましい。結着剤には、他にＰＶＤＦ、ＰＶＤＦの変性体などを用いることもできる。   The binder used for forming the negative electrode is not particularly limited, but rubber particles are preferably used from the viewpoint of obtaining a sufficient binding property with a small amount. In particular, it is preferable to use rubber particles containing a styrene unit and a butadiene unit. Examples of such a binder include a styrene-butadiene copolymer (SBR) and a modified SBR. When rubber particles are used as the negative electrode binder, it is preferable to use a thickener in combination. Examples of the thickener include those containing a water-soluble polymer. As the water-soluble polymer, a cellulose resin is preferable, and CMC is particularly preferable. In addition, PVDF, a modified form of PVDF, and the like can also be used as the binder.

負極は、例えば以下のようにして作製する。
負極活物質と、必要に応じて結着剤と、所定の分散媒とを混合し、負極合剤ペーストを調製する。次いで、負極合剤ペーストを負極集電体の表面に塗布して、乾燥後、合剤層の膜を形成する。その後、合剤層の膜を圧縮して負極が得られる。
分散媒は特に限定されず、例えば正極用の分散媒として挙げたものと同様のものを用いればよい。 The negative electrode is produced, for example, as follows.
A negative electrode active material, a binder as required, and a predetermined dispersion medium are mixed to prepare a negative electrode mixture paste. Next, the negative electrode mixture paste is applied to the surface of the negative electrode current collector, and after drying, a film of the mixture layer is formed. Thereafter, the film of the mixture layer is compressed to obtain a negative electrode.
The dispersion medium is not particularly limited. For example, the same dispersion medium as that described for the positive electrode may be used.

負極集電体としては、例えば銅などの負極電位下で安定な金属の箔、銅などの負極電位下で安定な金属を表層に配置したフィルムなどを用いることができる。なお、集電体の集電性をさらに向上させる観点から、表面に凹凸を設けたり、穿孔したりしてもよい。   As the negative electrode current collector, for example, a metal foil that is stable under a negative electrode potential such as copper, or a film in which a metal that is stable under a negative electrode potential such as copper is disposed on the surface layer can be used. In addition, from the viewpoint of further improving the current collecting property of the current collector, the surface may be provided with unevenness or perforated.

多孔質絶縁層は特に限定されないが、電池の使用環境に耐え得る材料であり、電解液のイオンを透過させることができ、正極と負極とを絶縁する性質を有する微多孔膜や不織布であることが好ましい。例えば、ポリオレフィン樹脂からなる微多孔膜が挙げられる。ポリオレフィン樹脂としては、ポリエチレン、ポリプロピレンなどが用いられる。微多孔膜は、１種の樹脂のみからなる単層膜であってもよく、２種以上の樹脂からなる多層膜、あるいは樹脂とアルミナなどの無機材料からなる多層膜であってもよい。   Although the porous insulating layer is not particularly limited, it is a material that can withstand the use environment of the battery, and can be a microporous film or nonwoven fabric that can permeate ions of the electrolyte and insulates the positive electrode from the negative electrode. Is preferred. For example, a microporous film made of a polyolefin resin can be mentioned. As the polyolefin resin, polyethylene, polypropylene, or the like is used. The microporous film may be a single layer film made of only one kind of resin, a multilayer film made of two or more kinds of resins, or a multilayer film made of an inorganic material such as resin and alumina.

非水電解質は、非水溶媒と、非水溶媒に溶解される溶質とを含む。
非水溶媒は特に限定されず、例えば、従来から非水溶媒として用いられているものを特に制限なく用いることができる。例えば、カーボネート類、ハロゲン化炭化水素、エーテル類、ケトン類、ニトリル類、ラクトン類、オキソラン化合物などが挙げられる。特に、エチレンカーボネート、プロピレンカーボネートなどの高誘電率溶媒と、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などの低粘性溶媒との混合溶媒が好ましい。また、副溶媒として、ジメトキシエタン、テトラヒドロフランおよびγ−ブチロラクトンなどを用いてもよい。 The nonaqueous electrolyte includes a nonaqueous solvent and a solute dissolved in the nonaqueous solvent.
A nonaqueous solvent is not specifically limited, For example, what was conventionally used as a nonaqueous solvent can be especially used without a restriction | limiting. For example, carbonates, halogenated hydrocarbons, ethers, ketones, nitriles, lactones, oxolane compounds and the like can be mentioned. In particular, a mixed solvent of a high dielectric constant solvent such as ethylene carbonate or propylene carbonate and a low viscosity solvent such as dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate is preferable. Further, dimethoxyethane, tetrahydrofuran, γ-butyrolactone, or the like may be used as a co-solvent.

非水電解質は、保存特性、サイクル特性、安全性などの電池特性を向上させるために、種々の添加剤を含んでもよい。添加剤としては、ビニレンカーボネート、シクロヘキシルベンゼン、およびそれらの誘導体などが挙げられる。
溶質は特に限定されないが、例えば、ＬｉＰＦ6、ＬｉＢＦ4、ＬｉＣｌＯ4およびＬｉＡｓＦ6から選ばれる無機塩、該無機塩の誘導体、ＬｉＳＯ3ＣＦ3、ＬｉＣ（ＳＯ3ＣＦ3）2、ＬｉＮ（ＳＯ3ＣＦ3）2、ＬｉＮ（ＳＯ2Ｃ2Ｆ5）2およびＬｉＮ（ＳＯ2ＣＦ3）（ＳＯ2Ｃ4Ｆ9）から選ばれる有機塩、並びにその誘導体を用いることができる。
非水電解質における溶質の濃度は特に限定されず、例えば０．５〜２．０ｍｏｌ／Ｌである。 The nonaqueous electrolyte may contain various additives in order to improve battery characteristics such as storage characteristics, cycle characteristics, and safety. Examples of the additive include vinylene carbonate, cyclohexylbenzene, and derivatives thereof.
The solute is not particularly limited. For example, an inorganic salt selected from LiPF 6 , LiBF 4 , LiClO 4 and LiAsF 6 , a derivative of the inorganic salt, LiSO 3 CF 3 , LiC (SO 3 CF 3 ) 2 , LiN (SO 3 An organic salt selected from CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 and LiN (SO 2 CF 3 ) (SO 2 C 4 F 9 ), and derivatives thereof can be used.
The concentration of the solute in the nonaqueous electrolyte is not particularly limited, and is, for example, 0.5 to 2.0 mol / L.

電池ケースは特に限定されず、例えば公知の材料を適宜用いることができる。材料としては、例えば、アルミニウム合金、ニッケルめっきを施した鉄合金、各種樹脂と金属との積層体などが挙げられる。   A battery case is not specifically limited, For example, a well-known material can be used suitably. Examples of the material include aluminum alloys, nickel-plated iron alloys, and laminates of various resins and metals.

以下、実施例および比較例を用いて本発明を具体的に説明する。なお、これらの実施例は、本発明を限定するものではない。   Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In addition, these Examples do not limit this invention.

＜正極活物質および導電剤の分級＞
正極活物質としてＬｉＮｉＯ2（日本化学工業（株）製の「セルシードＮ」、真密度４．７６ｇ／ｃｍ3）を使用した。この正極活物質を分級機（日鉄鉱業（株）製の「エルボージェット」）で分級して、互いに粒度が異なる６種類のサンプルを調製した。これら６種類のサンプルは、分級点が１μｍ、２．５μｍ、５μｍ、１０μｍ、２０μｍおよび５０μｍとなるように調整した。 <Classification of positive electrode active material and conductive agent>
LiNiO 2 (“Cell Seed N” manufactured by Nippon Chemical Industry Co., Ltd., true density 4.76 g / cm 3 ) was used as the positive electrode active material. This positive electrode active material was classified by a classifier (“Elbow Jet” manufactured by Nittetsu Mining Co., Ltd.) to prepare six types of samples having different particle sizes. These six types of samples were adjusted so that the classification points were 1 μm, 2.5 μm, 5 μm, 10 μm, 20 μm and 50 μm.

導電剤として黒鉛（比重２．０）を使用した。この導電剤を分級機（エルボージェット）で分級して、互いに粒度が異なる６種類のサンプルを調製した。これら６種類のサンプルは、分級点が１μｍ、２．５μｍ、５μｍ、１０μｍ、２０μｍおよび５０μｍとなるように調整した。
正極活物質および導電剤の粒度分布は、粒度分布測定装置（Ｓｙｍｐａｔｅｃ社製の「ＨＥＬＯＳ＆ＲＯＤＯＳ」）を用いて計測した。 Graphite (specific gravity 2.0) was used as a conductive agent. This conductive agent was classified with a classifier (elbow jet) to prepare six types of samples having different particle sizes. These six types of samples were adjusted so that the classification points were 1 μm, 2.5 μm, 5 μm, 10 μm, 20 μm and 50 μm.
The particle size distribution of the positive electrode active material and the conductive agent was measured using a particle size distribution measuring device (“HELOS & RODOS” manufactured by Sympatec).

＜正極の作製＞
比較例１
上述のようにして調製された、互いに粒度の異なる複数種の正極活物質および導電剤を混合して、混合物を得た。この混合物における導電剤の含有割合は、正極活物質１００質量部に対して０．５質量部とした。また、この混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率の粒度分布積算曲線において、積算ふるい下百分率の０〜３０％の範囲の一次回帰直線の相関係数Ｒは０．９４となるように調整した。 <Preparation of positive electrode>
Comparative Example 1
A plurality of types of positive electrode active materials and conductive agents prepared as described above and having different particle sizes were mixed to obtain a mixture. The content ratio of the conductive agent in this mixture was 0.5 parts by mass with respect to 100 parts by mass of the positive electrode active material. In addition, in the particle size distribution integration curve of the volume-based cumulative sieving percentage with respect to the common logarithmic value of the particle size (μm) of this mixture, the correlation coefficient R of the linear regression line in the range of 0-30% of the cumulative sieving percentage is Adjustment was made to be 0.94.

こうして得られた正極活物質と導電剤との混合物３ｋｇに、ＰＶＤＦのＮＭＰ溶液（ＰＶＤＦの含有量：１２質量％、呉羽化学（株）製の商品名「＃１３２０」）１ｋｇと、分散媒である適量のＮＭＰとを加えて、双腕式練合機にて攪拌し、正極合剤ペーストを調製した。次いで、得られた正極合剤ペーストを、正極集電体である厚さ１５μｍのアルミニウム箔の両面に、正極リードの接続部を除いて塗布することにより、正極合剤層の塗膜を形成した。得られた塗膜は、乾燥させた状態で、かつ圧延していない状態で、塗膜の体積に占める正極活物質の体積比率が約０．３であった。   In 3 kg of the mixture of the positive electrode active material and the conductive agent thus obtained, 1 kg of PVDF NMP solution (PVDF content: 12 mass%, trade name “# 1320” manufactured by Kureha Chemical Co., Ltd.), and a dispersion medium An appropriate amount of NMP was added and stirred with a double-arm kneader to prepare a positive electrode mixture paste. Next, the obtained positive electrode mixture paste was applied to both surfaces of a 15 μm-thick aluminum foil serving as a positive electrode current collector, excluding the connection portion of the positive electrode lead, thereby forming a coating film of the positive electrode mixture layer. . The obtained coating film had a volume ratio of the positive electrode active material to a volume of the coating film of about 0.3 in a dried state and not rolled.

塗膜の乾燥後、正極合剤層における正極活物質の体積比率が０．６５となるように、ローラを用いて塗膜を圧延することにより、正極を作製した。その後、１８６５０型円筒型リチウムイオン電池の電池ケースに挿入可能な幅に正極をスリットして、正極フープを得た。   After the coating film was dried, the coating film was rolled using a roller so that the volume ratio of the cathode active material in the cathode mixture layer was 0.65, thereby producing a cathode. Thereafter, the positive electrode was slit into a width that could be inserted into a battery case of a 18650-type cylindrical lithium ion battery to obtain a positive electrode hoop.

正極の一部をサンプリングして、正極合剤層に占める正極活物質の体積比率を測定した。正極活物質の体積比率は、（正極活物質の真体積）／（正極合剤層の見かけ体積）により求めた。正極活物質の真体積は、正極活物質の真密度と質量との積から計算した。また、正極合剤層の見かけ体積は、正極合剤層の厚さと面積から計算した。   A part of the positive electrode was sampled, and the volume ratio of the positive electrode active material in the positive electrode mixture layer was measured. The volume ratio of the positive electrode active material was determined by (true volume of positive electrode active material) / (apparent volume of positive electrode mixture layer). The true volume of the positive electrode active material was calculated from the product of the true density and mass of the positive electrode active material. The apparent volume of the positive electrode mixture layer was calculated from the thickness and area of the positive electrode mixture layer.

比較例２および実施例１
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例１と同様にして正極を作製した。塗膜の圧延の程度は、正極合剤層における正極活物質の体積比率（以下、単に「正極活物質の体積比率」という）が比較例２において０．７５となるように調整し、実施例１において０．９０となるように調整した。 Comparative Example 2 and Example 1
A positive electrode was produced in the same manner as in Comparative Example 1 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material in the positive electrode mixture layer (hereinafter simply referred to as “volume ratio of the positive electrode active material”) was 0.75 in Comparative Example 2. 1 was adjusted to 0.90.

比較例３
正極活物質１００質量部に対する導電剤の含有割合を１質量部としたこと以外は比較例１と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例４および実施例２
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例３と同様にして正極を作製した。塗膜の圧延の程度は、比較例４において正極活物質の体積比率が０．７５となるように調整し、実施例２において正極活物質の体積比率が最大限となるように調整した。実施例２における正極活物質の体積比率は０．８８であった。 Comparative Example 3
A positive electrode was obtained in the same manner as in Comparative Example 1 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 1 part by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 4 and Example 2
A positive electrode was produced in the same manner as in Comparative Example 3 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 4, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Example 2. The volume ratio of the positive electrode active material in Example 2 was 0.88.

比較例５
正極活物質１００質量部に対する導電剤の含有割合を３質量部としたこと以外は比較例１と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例６および実施例３
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例５と同様にして正極を作製した。塗膜の圧延の程度は、比較例６において正極活物質の体積比率が０．７５となるように調整し、実施例３において正極活物質の体積比率が最大限となるように調整した。実施例３における正極活物質の体積比率は０．８５であった。 Comparative Example 5
A positive electrode was obtained in the same manner as in Comparative Example 1 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 3 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 6 and Example 3
A positive electrode was produced in the same manner as in Comparative Example 5 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 6, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Example 3. The volume ratio of the positive electrode active material in Example 3 was 0.85.

比較例７
正極活物質１００質量部に対する導電剤の含有割合を４質量部としたこと以外は比較例１と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例８および実施例４
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例７と同様にして正極を作製した。塗膜の圧延の程度は、比較例８において正極活物質の体積比率が０．７５となるように調整し、実施例４において正極活物質の体積比率が最大限となるように調整した。実施例４における正極活物質の体積比率は０．８１であった。 Comparative Example 7
A positive electrode was obtained in the same manner as in Comparative Example 1 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 4 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 8 and Example 4
A positive electrode was produced in the same manner as in Comparative Example 7, except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 8, and was adjusted so that the volume ratio of the positive electrode active material was maximum in Example 4. The volume ratio of the positive electrode active material in Example 4 was 0.81.

比較例９
互いに粒度の異なる複数種の正極活物質および導電剤を混合して、混合物を得た。この混合物は、導電剤の含有割合を正極活物質１００質量部に対して０．５質量部とした。また、上述の相関係数Ｒは０．９７となるように調整した。こうして得られた正極活物質と導電剤との混合物を用いたこと以外は比較例１と同様にして正極を作製した。正極活物質の体積比率は０．６５となるように調整した。 Comparative Example 9
A plurality of positive electrode active materials and conductive agents having different particle sizes were mixed to obtain a mixture. This mixture made the content rate of a electrically conductive agent 0.5 mass part with respect to 100 mass parts of positive electrode active materials. The correlation coefficient R described above was adjusted to be 0.97. A positive electrode was produced in the same manner as in Comparative Example 1 except that the mixture of the positive electrode active material and the conductive agent thus obtained was used. The volume ratio of the positive electrode active material was adjusted to 0.65.

比較例１０および実施例５
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例９と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が比較例１０において０．７５となるように調整し、実施例５において０．９０となるように調整した。 Comparative Example 10 and Example 5
A positive electrode was produced in the same manner as in Comparative Example 9 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 10 and 0.90 in Example 5.

比較例１１
正極活物質１００質量部に対する導電剤の含有割合を１質量部としたこと以外は比較例９と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例１２および実施例６
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例１１と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が比較例１２において０．７５となるように調整し、実施例６において０．９０となるように調整した。 Comparative Example 11
A positive electrode was obtained in the same manner as in Comparative Example 9 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 1 part by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 12 and Example 6
A positive electrode was produced in the same manner as in Comparative Example 11 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 12, and was adjusted to 0.90 in Example 6.

比較例１３
正極活物質１００質量部に対する導電剤の含有割合を３質量部としたこと以外は比較例９と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例１４および実施例７
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例１３と同様にして正極を作製した。塗膜の圧延の程度は、比較例１４において正極活物質の体積比率が０．７５となるように調整し、実施例７において正極活物質の体積比率が最大限となるように調整した。実施例７における正極活物質の体積比率は０．８７であった。 Comparative Example 13
A positive electrode was obtained in the same manner as in Comparative Example 9 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 3 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 14 and Example 7
A positive electrode was produced in the same manner as in Comparative Example 13 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 14, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Example 7. The volume ratio of the positive electrode active material in Example 7 was 0.87.

比較例１５
正極活物質１００質量部に対する導電剤の含有割合を４質量部としたこと以外は比較例９と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例１６および実施例８
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例１５と同様にして正極を作製した。塗膜の圧延の程度は、比較例１６において正極活物質の体積比率が０．７５となるように調整し、実施例８において正極活物質の体積比率が最大限となるように調整した。実施例８における正極活物質の体積比率は０．８４であった。 Comparative Example 15
A positive electrode was obtained in the same manner as in Comparative Example 9 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 4 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 16 and Example 8
A positive electrode was produced in the same manner as in Comparative Example 15 except that the degree of rolling of the coating film during production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 16, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Example 8. The volume ratio of the positive electrode active material in Example 8 was 0.84.

比較例１７
互いに粒度の異なる複数種の正極活物質および導電剤を混合して、混合物を得た。この混合物は、導電剤の含有割合を正極活物質１００質量部に対して０．５質量部とした。また、上述の相関係数Ｒは１となるように調整した。こうして得られた正極活物質と導電剤との混合物を用いたこと以外は比較例１と同様にして正極を作製した。正極活物質の体積比率は０．６５となるように調整した。 Comparative Example 17
A plurality of positive electrode active materials and conductive agents having different particle sizes were mixed to obtain a mixture. This mixture made the content rate of a electrically conductive agent 0.5 mass part with respect to 100 mass parts of positive electrode active materials. The correlation coefficient R described above was adjusted to be 1. A positive electrode was produced in the same manner as in Comparative Example 1 except that the mixture of the positive electrode active material and the conductive agent thus obtained was used. The volume ratio of the positive electrode active material was adjusted to 0.65.

比較例１８および実施例９
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例１７と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が比較例１８において０．７５となるように調整し、実施例９において０．９０となるように調整した。 Comparative Example 18 and Example 9
A positive electrode was produced in the same manner as in Comparative Example 17 except that the degree of rolling of the coating film during production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 18, and was adjusted to 0.90 in Example 9.

比較例１９
正極活物質１００質量部に対する導電剤の含有割合を１質量部としたこと以外は比較例９と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例２０および実施例１０
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例１９と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が比較例２０において０．７５となるように調整し、実施例１０において０．９０となるように調整した。 Comparative Example 19
A positive electrode was obtained in the same manner as in Comparative Example 9 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 1 part by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 20 and Example 10
A positive electrode was produced in the same manner as in Comparative Example 19 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 20, and was adjusted to 0.90 in Example 10.

比較例２１
正極活物質１００質量部に対する導電剤の含有割合を３質量部としたこと以外は比較例１９と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例２２および実施例１１
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例２１と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が比較例２２において０．７５となるように調整し、実施例１１において０．９０となるように調整した。 Comparative Example 21
A positive electrode was obtained in the same manner as in Comparative Example 19 except that the content ratio of the conductive agent with respect to 100 parts by mass of the positive electrode active material was 3 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 22 and Example 11
A positive electrode was produced in the same manner as in Comparative Example 21, except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 22 and adjusted to 0.90 in Example 11.

比較例２３
正極活物質１００質量部に対する導電剤の含有割合を４質量部としたこと以外は比較例１９と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例２４および実施例１２
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例２３と同様にして正極を作製した。塗膜の圧延の程度は、比較例２４において正極活物質の体積比率が０．７５となるように調整し、実施例１２において正極活物質の体積比率が最大限となるように調整した。実施例１２における正極活物質の体積比率は０．８７であった。 Comparative Example 23
A positive electrode was obtained in the same manner as in Comparative Example 19 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was changed to 4 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 24 and Example 12
A positive electrode was produced in the same manner as in Comparative Example 23 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 24, and was adjusted so that the volume ratio of the positive electrode active material was maximum in Example 12. The volume ratio of the positive electrode active material in Example 12 was 0.87.

比較例２５
互いに粒度の異なる複数種の正極活物質および導電剤を混合して、混合物を得た。この混合物は、導電剤の含有割合を正極活物質１００質量部に対して０．５質量部とした。また、上述の相関係数Ｒは０．７９となるように調整した。こうして得られた正極活物質と導電剤との混合物を用いたこと以外は比較例１と同様にして正極を作製した。正極活物質の体積比率は０．６５となるように調整した。 Comparative Example 25
A plurality of positive electrode active materials and conductive agents having different particle sizes were mixed to obtain a mixture. This mixture made the content rate of a electrically conductive agent 0.5 mass part with respect to 100 mass parts of positive electrode active materials. The correlation coefficient R described above was adjusted to be 0.79. A positive electrode was produced in the same manner as in Comparative Example 1 except that the mixture of the positive electrode active material and the conductive agent thus obtained was used. The volume ratio of the positive electrode active material was adjusted to 0.65.

比較例２６および２７
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例２５と同様にして正極を作製した。塗膜の圧延の程度は、比較例２６において正極活物質の体積比率が０．７５となるように調整し、比較例２７において正極活物質の体積比率が最大限となるように調整した。比較例２７における正極活物質の体積比率は０．８０であった。 Comparative Examples 26 and 27
A positive electrode was produced in the same manner as in Comparative Example 25 except that the degree of rolling of the coating film during production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 26, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Comparative Example 27. The volume ratio of the positive electrode active material in Comparative Example 27 was 0.80.

比較例２８
正極活物質１００質量部に対する導電剤の含有割合を１質量部としたこと以外は比較例２５と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例２９および３０
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例２８と同様にして正極を作製した。塗膜の圧延の程度は、比較例２９において正極活物質の体積比率が０．７５となるように調整し、比較例３０において正極活物質の体積比率が最大限となるように調整した。比較例３０における正極活物質の体積比率は０．７６であった。 Comparative Example 28
A positive electrode was obtained in the same manner as in Comparative Example 25 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 1 part by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Examples 29 and 30
A positive electrode was produced in the same manner as in Comparative Example 28 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 29, and was adjusted so that the volume ratio of the positive electrode active material was maximum in Comparative Example 30. The volume ratio of the positive electrode active material in Comparative Example 30 was 0.76.

比較例３１
正極活物質１００質量部に対する導電剤の含有割合を３質量部としたこと以外は比較例２５と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例３２
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例３１と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が最大限となるように調整した。正極活物質の体積比率は０．７４であった。 Comparative Example 31
A positive electrode was obtained in the same manner as in Comparative Example 25 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 3 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 32
A positive electrode was produced in the same manner as in Comparative Example 31 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was maximized. The volume ratio of the positive electrode active material was 0.74.

比較例３３
正極活物質１００質量部に対する導電剤の含有割合を４質量部としたこと以外は比較例２５と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例３４
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例３３と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が最大限となるように調整した。正極活物質の体積比率は０．６９であった。 Comparative Example 33
A positive electrode was obtained in the same manner as in Comparative Example 25 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 4 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 34
A positive electrode was produced in the same manner as in Comparative Example 33 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was maximized. The volume ratio of the positive electrode active material was 0.69.

比較例３５
互いに粒度の異なる複数種の正極活物質および導電剤を混合して、混合物を得た。この混合物は、導電剤の含有割合を正極活物質１００質量部に対して０．５質量部とした。また、上述の相関係数Ｒは０．９１となるように調整した。こうして得られた正極活物質と導電剤との混合物を用いたこと以外は比較例１と同様にして正極を作製した。正極活物質の体積比率は０．６５となるように調整した。 Comparative Example 35
A plurality of positive electrode active materials and conductive agents having different particle sizes were mixed to obtain a mixture. This mixture made the content rate of a electrically conductive agent 0.5 mass part with respect to 100 mass parts of positive electrode active materials. The correlation coefficient R described above was adjusted to be 0.91. A positive electrode was produced in the same manner as in Comparative Example 1 except that the mixture of the positive electrode active material and the conductive agent thus obtained was used. The volume ratio of the positive electrode active material was adjusted to 0.65.

比較例３６および３７
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例３５と同様にして正極を作製した。塗膜の圧延の程度は、比較例３６において正極活物質の体積比率が０．７５となるように調整し、比較例３７において正極活物質の体積比率が最大限となるように調整した。比較例３７における正極活物質の体積比率は０．８２であった。 Comparative Examples 36 and 37
A positive electrode was produced in the same manner as in Comparative Example 35 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 36, and was adjusted so that the volume ratio of the positive electrode active material was maximum in Comparative Example 37. The volume ratio of the positive electrode active material in Comparative Example 37 was 0.82.

比較例３８
正極活物質１００質量部に対する導電剤の含有割合を１質量部としたこと以外は比較例３５と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例３９および４０
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例３８と同様にして正極を作製した。塗膜の圧延の程度は、比較例３９において正極活物質の体積比率が０．７５となるように調整し、比較例４０において正極活物質の体積比率が最大限となるように調整した。比較例４０における正極活物質の体積比率は０．７９であった。 Comparative Example 38
A positive electrode was obtained in the same manner as in Comparative Example 35 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 1 part by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Examples 39 and 40
A positive electrode was produced in the same manner as in Comparative Example 38 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 39, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Comparative Example 40. The volume ratio of the positive electrode active material in Comparative Example 40 was 0.79.

比較例４１
正極活物質１００質量部に対する導電剤の含有割合を３質量部としたこと以外は比較例３５と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例４２および４３
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例４１と同様にして正極を作製した。塗膜の圧延の程度は、比較例４２において正極活物質の体積比率が０．７５となるように調整し、比較例４３において正極活物質の体積比率が最大限となるように調整した。比較例４３における正極活物質の体積比率は０．７６であった。 Comparative Example 41
A positive electrode was obtained in the same manner as in Comparative Example 35 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 3 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Examples 42 and 43
A positive electrode was produced in the same manner as in Comparative Example 41 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 42, and was adjusted so that the volume ratio of the positive electrode active material was maximum in Comparative Example 43. The volume ratio of the positive electrode active material in Comparative Example 43 was 0.76.

比較例４４
正極活物質１００質量部に対する導電剤の含有割合を４質量部としたこと以外は比較例３５と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例４５
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例４４と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が最大限となるように調整した。正極活物質の体積比率は０．７１であった。 Comparative Example 44
A positive electrode was obtained in the same manner as in Comparative Example 35 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was changed to 4 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 45
A positive electrode was produced in the same manner as in Comparative Example 44 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was maximized. The volume ratio of the positive electrode active material was 0.71.

比較例４６
互いに粒度の異なる複数種の正極活物質および導電剤を混合して、混合物を得た。この混合物は、導電剤の含有割合を正極活物質１００質量部に対して０．５質量部とした。また、上述の相関係数Ｒは０．９２となるように調整した。こうして得られた正極活物質と導電剤との混合物を用いたこと以外は比較例１と同様にして正極を作製した。 Comparative Example 46
A plurality of positive electrode active materials and conductive agents having different particle sizes were mixed to obtain a mixture. This mixture made the content rate of a electrically conductive agent 0.5 mass part with respect to 100 mass parts of positive electrode active materials. The correlation coefficient R described above was adjusted to be 0.92. A positive electrode was produced in the same manner as in Comparative Example 1 except that the mixture of the positive electrode active material and the conductive agent thus obtained was used.

比較例４７および４８
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例４６と同様にして正極を作製した。塗膜の圧延の程度は、比較例４７において正極活物質の体積比率が０．７５となるように調整し、比較例４８において正極活物質の体積比率が最大限となるように調整した。比較例４８における正極活物質の体積比率は０．８４であった。 Comparative Examples 47 and 48
A positive electrode was produced in the same manner as in Comparative Example 46 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted in Comparative Example 47 so that the volume ratio of the positive electrode active material was 0.75, and in Comparative Example 48, the volume ratio of the positive electrode active material was adjusted to the maximum. The volume ratio of the positive electrode active material in Comparative Example 48 was 0.84.

比較例４９
正極活物質１００質量部に対する導電剤の含有割合を１質量部としたこと以外は比較例４６と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例５０および５１
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例４９と同様にして正極を作製した。塗膜の圧延の程度は、比較例５０において正極活物質の体積比率が０．７５となるように調整し、比較例５１において正極活物質の体積比率が最大限となるように調整した。比較例５１における正極活物質の体積比率は０．８０であった。 Comparative Example 49
A positive electrode was obtained in the same manner as in Comparative Example 46 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 1 part by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Examples 50 and 51
A positive electrode was produced in the same manner as in Comparative Example 49 except that the degree of rolling of the coating film during production of the positive electrode was increased. The degree of rolling of the coating film was adjusted in Comparative Example 50 so that the volume ratio of the positive electrode active material was 0.75, and in Comparative Example 51, the volume ratio of the positive electrode active material was adjusted to the maximum. The volume ratio of the positive electrode active material in Comparative Example 51 was 0.80.

比較例５２
正極活物質１００質量部に対する導電剤の含有割合を３質量部としたこと以外は比較例４６と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例５３および５４
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例５２と同様にして正極を作製した。塗膜の圧延の程度は、比較例５３において正極活物質の体積比率が０．７５となるように調整し、比較例５４において正極活物質の体積比率が最大限となるように調整した。比較例５４における正極活物質の体積比率は０．７６であった。 Comparative Example 52
A positive electrode was obtained in the same manner as in Comparative Example 46 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was 3 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Examples 53 and 54
A positive electrode was produced in the same manner as in Comparative Example 52 except that the degree of rolling of the coating film during production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was 0.75 in Comparative Example 53, and was adjusted so that the volume ratio of the positive electrode active material was maximized in Comparative Example 54. The volume ratio of the positive electrode active material in Comparative Example 54 was 0.76.

比較例５５
正極活物質１００質量部に対する導電剤の含有割合を４質量部としたこと以外は比較例４６と同様にして正極を得た。正極活物質の体積比率は０．６５となるように調整した。
比較例５６
正極作製時の塗膜の圧延の程度を強めたこと以外は比較例５５と同様にして正極を作製した。塗膜の圧延の程度は、正極活物質の体積比率が最大限となるように調整した。正極活物質の体積比率は０．７０であった。 Comparative Example 55
A positive electrode was obtained in the same manner as in Comparative Example 46 except that the content ratio of the conductive agent to 100 parts by mass of the positive electrode active material was changed to 4 parts by mass. The volume ratio of the positive electrode active material was adjusted to 0.65.
Comparative Example 56
A positive electrode was produced in the same manner as in Comparative Example 55 except that the degree of rolling of the coating film during the production of the positive electrode was increased. The degree of rolling of the coating film was adjusted so that the volume ratio of the positive electrode active material was maximized. The volume ratio of the positive electrode active material was 0.70.

＜リチウム二次電池の作製＞
上記実施例および比較例の正極について、それぞれリチウム二次電池を作製して、その物性を評価した。リチウム二次電池の作製方法および物性の評価方法を下記に示す。 <Production of lithium secondary battery>
Regarding the positive electrodes of the above examples and comparative examples, lithium secondary batteries were prepared and their physical properties were evaluated. A method for manufacturing a lithium secondary battery and a method for evaluating physical properties are described below.

（ａ）負極の作製
負極活物質である人造黒鉛３ｋｇに、負極結着剤（日本ゼオン（株）製の商品名「ＢＭ−４００Ｂ」、スチレン−ブタジエン共重合体の変性体を４０質量％含む水性分散液）７５ｇと、増粘剤であるＣＭＣを３０ｇと、分散媒である適量の水とを加えて、双腕式練合機にて攪拌し、負極合剤ペーストを調製した。次いで、得られた負極合剤ペーストを、負極集電体である厚さ１０μｍの銅箔の両面に、負極リードの接続部を除いて塗布することにより、負極合剤層の塗膜を形成した。塗膜の乾燥後、ローラを用いて塗膜を圧延することにより、負極活物質層密度（負極活物質の質量／負極合剤層の体積）が１．４ｇ／ｃｍ3である、負極合剤層を形成した。このとき、負極集電体および負極合剤層からなる負極の厚みを１８０μｍとなるように制御した。その後、１８６５０型円筒型リチウムイオン電池の電池ケースに挿入可能な幅に極板をスリットし、負極のフープを得た。 (A) Production of negative electrode 3 kg of artificial graphite as a negative electrode active material contains a negative electrode binder (trade name “BM-400B” manufactured by Nippon Zeon Co., Ltd.) and 40% by mass of a modified styrene-butadiene copolymer. Aqueous dispersion liquid (75 g), 30 g of thickener CMC and an appropriate amount of water as a dispersion medium were added and stirred with a double-arm kneader to prepare a negative electrode mixture paste. Next, the obtained negative electrode mixture paste was applied to both surfaces of a 10 μm-thick copper foil, which is a negative electrode current collector, except for the connecting portion of the negative electrode lead, thereby forming a coating film of the negative electrode mixture layer. . After the coating film is dried, the negative electrode active material layer density (mass of negative electrode active material / volume of negative electrode mixture layer) is 1.4 g / cm 3 by rolling the coating film using a roller. A layer was formed. At this time, the thickness of the negative electrode composed of the negative electrode current collector and the negative electrode mixture layer was controlled to be 180 μm. Thereafter, the electrode plate was slit to a width that could be inserted into the battery case of a 18650-type cylindrical lithium ion battery to obtain a negative electrode hoop.

（ｂ）非水電解質の調製
エチレンカーボネートと、ジメチルカーボネートと、エチルメチルカーボネートとを体積比２：３：３で混合した非水溶媒に、溶質であるＬｉＰＦ6を１ｍｏｌ／Ｌの濃度で溶解させて、非水電解質を調製した。また、非水電解質１００質量部あたり、ビニレンカーボネートを３質量部添加した。 (B) Preparation of non-aqueous electrolyte LiPF 6 as a solute was dissolved at a concentration of 1 mol / L in a non-aqueous solvent in which ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate were mixed at a volume ratio of 2: 3: 3. A non-aqueous electrolyte was prepared. Moreover, 3 mass parts of vinylene carbonate was added per 100 mass parts of nonaqueous electrolyte.

（ｃ）リチウム二次電池の作製
以下の手順で、図４に示す円筒型リチウムイオン電池（１８６５０型）を作製した。
まず、正極５と負極６とを、それぞれ電池ケース１に挿入可能な長さに切断した。正極リード接続部には正極リード５ａの一端を接続し、負極リード接続部には負極リード６ａの一端を接続した。その後、正極５と負極６との間に、厚み１５μｍのポリエチレン樹脂製の微多孔膜からなる多孔質絶縁層７を介して巻回し、円筒状の電極群を作製した。この電極群を、上部絶縁リング８ａと下部絶縁リング８ｂとで挟持して、電池ケース１に収容し、非水電解質５ｇを電池ケース１内に注入した。正極リード５ａの他端は、正極端子として兼用される電池蓋２の裏面に溶接した。負極リード６ａの他端は、電池ケース１の内底面に溶接した。次いで、電池ケース１の開口部を、周縁に絶縁パッキン３が配された電池蓋２で密閉して、電池ケース１内を１３３Ｐａ（ａｂｓ）に減圧することにより、非水電解質を電極群に含浸させた。こうして、円筒型リチウムイオン電池を得た。 (C) Production of Lithium Secondary Battery A cylindrical lithium ion battery (18650 type) shown in FIG. 4 was produced by the following procedure.
First, the positive electrode 5 and the negative electrode 6 were each cut to a length that can be inserted into the battery case 1. One end of the positive electrode lead 5a was connected to the positive electrode lead connection portion, and one end of the negative electrode lead 6a was connected to the negative electrode lead connection portion. Then, it wound between the positive electrode 5 and the negative electrode 6 through the porous insulating layer 7 which consists of a microporous film made from a polyethylene resin with a thickness of 15 μm, and a cylindrical electrode group was produced. The electrode group was sandwiched between the upper insulating ring 8a and the lower insulating ring 8b, accommodated in the battery case 1, and the nonaqueous electrolyte 5g was injected into the battery case 1. The other end of the positive electrode lead 5a was welded to the back surface of the battery lid 2 also used as a positive electrode terminal. The other end of the negative electrode lead 6 a was welded to the inner bottom surface of the battery case 1. Next, the opening of the battery case 1 is sealed with a battery lid 2 having an insulating packing 3 arranged on the periphery, and the inside of the battery case 1 is decompressed to 133 Pa (abs), thereby impregnating the electrode group with a nonaqueous electrolyte. I let you. Thus, a cylindrical lithium ion battery was obtained.

（ｄ）電池の充放電試験
上記円筒型リチウムイオン電池に対して、２０℃の環境温度下で、３Ｖ〜４．２Ｖ間を１０００ｍＡの定電流で充電と放電を行い、放電時間と電流値との積を放電容量（ｍＡｈ）とした。放電容量を正極に含まれる活物質の質量で除することにより、放電容量密度（ｍＡｈ／ｇ）を求めた。 (D) Battery charging / discharging test The cylindrical lithium ion battery is charged and discharged at a constant current of 1000 mA between 3 V and 4.2 V at an environmental temperature of 20 ° C. Was the discharge capacity (mAh). The discharge capacity density (mAh / g) was determined by dividing the discharge capacity by the mass of the active material contained in the positive electrode.

表１〜６に、正極活物質および導電剤の混合物における上述の相関係数Ｒと、正極活物質１００質量部に対する導電剤の含有割合（質量部）と、正極合剤層における正極活物質の体積比率と、リチウムイオン電池の放電容量とを、まとめて示す。
下記の表１〜６中、「導電剤の含有割合」は、正極活物質１００質量部に対する導電剤の含有割合を示す。「活物質の体積比率」は、正極合剤層に占める正極活物質の体積比率を示す。 Tables 1 to 6 show the correlation coefficient R in the mixture of the positive electrode active material and the conductive agent, the content ratio (part by mass) of the conductive agent with respect to 100 parts by mass of the positive electrode active material, and the positive electrode active material in the positive electrode mixture layer. The volume ratio and the discharge capacity of the lithium ion battery are collectively shown.
In the following Tables 1 to 6, “the content ratio of the conductive agent” indicates the content ratio of the conductive agent with respect to 100 parts by mass of the positive electrode active material. “Volume ratio of active material” indicates the volume ratio of the positive electrode active material in the positive electrode mixture layer.

Figure 2011134535
Figure 2011134535

Figure 2011134535
Figure 2011134535

Figure 2011134535
Figure 2011134535

Figure 2011134535
Figure 2011134535

Figure 2011134535
Figure 2011134535

Figure 2011134535
Figure 2011134535

表１に示したように、実施例１〜１２は、いずれも正極活物質および導電剤の混合物として、上述の相関係数Ｒが０．９４以上に調整されたものを用いた。さらに、正極合剤ペーストからなる塗膜の圧延によって、正極活物質の体積比率が０．８以上となるように調整された。これらの実施例によれば、正極の容量を極めて高くすることができた。
一方、正極活物質および導電剤の混合物について、上述の相関係数Ｒが０．９４を下回る場合には、正極合剤ペーストからなる塗膜を圧延しても、正極活物質の体積比率を０．８以上にすることができなかった。また、これらの場合には、正極の容量が低かった。 As shown in Table 1, in each of Examples 1 to 12, a mixture of the positive electrode active material and the conductive agent having the correlation coefficient R adjusted to 0.94 or more was used. Furthermore, it adjusted so that the volume ratio of a positive electrode active material might be set to 0.8 or more by rolling of the coating film which consists of positive mix pastes. According to these examples, the capacity of the positive electrode could be extremely increased.
On the other hand, for the mixture of the positive electrode active material and the conductive agent, when the correlation coefficient R is less than 0.94, the volume ratio of the positive electrode active material is reduced to 0 even if the coating film made of the positive electrode mixture paste is rolled. It was not possible to increase it to 8 or more. In these cases, the capacity of the positive electrode was low.

本発明のリチウム二次電池用正極は、従来のものに比べて高容量かつ高エネルギー密度である。それゆえ、本発明は、高容量および高エネルギー密度のリチウム二次電池を提供するという観点より有用である。   The positive electrode for a lithium secondary battery of the present invention has a higher capacity and a higher energy density than those of the conventional one. Therefore, the present invention is useful from the viewpoint of providing a lithium secondary battery having a high capacity and a high energy density.

１ 電池ケース、 ２ 電池蓋、 ３ 絶縁パッキン、 ５ 正極、 ５ａ 正極リード、 ６ 負極、 ６ａ 負極リード、 ７ 多孔質絶縁層、 ８ａ 上部絶縁リング、 ８ｂ 下部絶縁リング   DESCRIPTION OF SYMBOLS 1 Battery case, 2 Battery cover, 3 Insulation packing, 5 Positive electrode, 5a Positive electrode lead, 6 Negative electrode, 6a Negative electrode lead, 7 Porous insulating layer, 8a Upper insulating ring, 8b Lower insulating ring

Claims (6)

リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤層を備えたリチウム二次電池用正極であって、
前記正極合剤層における前記正極活物質の体積比率が０．８以上であり、
前記正極活物質および前記導電剤は、前記正極活物質１００質量部に対して前記導電剤を０．５〜４質量部含有し、かつ、それらの混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率で表される粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるような組み合わせで前記正極合剤層に含まれていることを特徴とするリチウム二次電池用正極。 A positive electrode for a lithium secondary battery comprising a positive electrode mixture layer containing a positive electrode active material capable of inserting and extracting lithium ions, a conductive agent, and a binder,
The volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more,
The positive electrode active material and the conductive agent contain 0.5 to 4 parts by mass of the conductive agent with respect to 100 parts by mass of the positive electrode active material, and the common logarithm of the particle size (μm) of the mixture thereof. Among the particle size distribution integrated curves represented by the volume-based integrated sieving percentage, the combination is such that the correlation coefficient R of the primary regression line in the range of the integrated sieving percentage in the range of 0 to 30% is 0.94 or more. A positive electrode for a lithium secondary battery, which is contained in a positive electrode mixture layer. 前記導電剤の含有量が、前記正極活物質１００質量部に対して１〜３質量部である請求項１に記載のリチウム二次電池用正極。   2. The positive electrode for a lithium secondary battery according to claim 1, wherein the content of the conductive agent is 1 to 3 parts by mass with respect to 100 parts by mass of the positive electrode active material. 前記正極合剤層における前記正極活物質の体積比率が０．８５以上である請求項１または２に記載のリチウム二次電池用正極の製造方法。   3. The method for producing a positive electrode for a lithium secondary battery according to claim 1, wherein a volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.85 or more. 前記正極活物質がリチウム遷移金属複合酸化物である請求項１〜３のいずれか１項に記載のリチウム二次電池用正極。   The positive electrode for a lithium secondary battery according to claim 1, wherein the positive electrode active material is a lithium transition metal composite oxide. 前記導電剤がアセチレンブラックである請求項１〜４のいずれか１項に記載のリチウム二次電池用正極。   The positive electrode for a lithium secondary battery according to claim 1, wherein the conductive agent is acetylene black. リチウム二次電池用正極の製造方法であって、
リチウムイオンを吸蔵および放出可能な正極活物質と、導電剤と、結着剤とを含む正極合剤ペーストを正極集電体に塗工して塗膜を形成する塗膜形成工程と、前記塗膜を圧延することにより正極合剤層を形成する圧延工程と、を備え、
前記正極活物質および前記導電剤として、前記正極活物質１００質量部に対して前記導電剤を０．５〜４質量部含有し、かつ、それらの混合物の粒径（μｍ）の常用対数値に対する体積基準の積算ふるい下百分率の粒度分布積算曲線のうち、積算ふるい下百分率が０〜３０％の範囲の一次回帰直線の相関係数Ｒが０．９４以上になるような組み合わせを用い、
前記圧延工程において、前記正極合剤層における前記正極活物質の体積比率が０．８以上となるように前記塗膜を圧延することを特徴とするリチウム二次電池用正極の製造方法。 A method for producing a positive electrode for a lithium secondary battery, comprising:
A coating film forming step of forming a coating film by applying a positive electrode mixture paste containing a positive electrode active material capable of occluding and releasing lithium ions, a conductive agent, and a binder to a positive electrode current collector; A rolling step of forming a positive electrode mixture layer by rolling the film,
As the positive electrode active material and the conductive agent, the conductive agent is contained in an amount of 0.5 to 4 parts by mass with respect to 100 parts by mass of the positive electrode active material, and the common logarithm of the particle diameter (μm) of the mixture thereof. Among the particle size distribution integration curves of the volume-based cumulative sieve percentage, use a combination in which the correlation coefficient R of the primary regression line in the range of the cumulative sieve percentage in the range of 0 to 30% is 0.94 or more,
In the rolling step, the coating film is rolled so that a volume ratio of the positive electrode active material in the positive electrode mixture layer is 0.8 or more.
JP2009291809A 2009-12-24 2009-12-24 Positive electrode for lithium secondary battery, and method for manufacturing the same Pending JP2011134535A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2009291809A JP2011134535A (en) 2009-12-24 2009-12-24 Positive electrode for lithium secondary battery, and method for manufacturing the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2009291809A JP2011134535A (en) 2009-12-24 2009-12-24 Positive electrode for lithium secondary battery, and method for manufacturing the same

Publications (1)

Publication Number Publication Date
JP2011134535A true JP2011134535A (en) 2011-07-07

Family

ID=44347061

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2009291809A Pending JP2011134535A (en) 2009-12-24 2009-12-24 Positive electrode for lithium secondary battery, and method for manufacturing the same

Country Status (1)

Country Link
JP (1) JP2011134535A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015023021A (en) * 2013-07-19 2015-02-02 三星エスディアイ株式会社Ｓａｍｓｕｎｇ ＳＤＩ Ｃｏ．，Ｌｔｄ． Positive active material for rechargeable lithium battery, method of manufacturing the same, and positive electrode and rechargeable lithium battery including the same
WO2015146024A1 (en) * 2014-03-27 2015-10-01 三洋電機株式会社 Non-aqueous electrolyte secondary battery
WO2017175697A1 (en) * 2016-04-04 2017-10-12 株式会社Ｇｓユアサ Power storage element

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015023021A (en) * 2013-07-19 2015-02-02 三星エスディアイ株式会社Ｓａｍｓｕｎｇ ＳＤＩ Ｃｏ．，Ｌｔｄ． Positive active material for rechargeable lithium battery, method of manufacturing the same, and positive electrode and rechargeable lithium battery including the same
WO2015146024A1 (en) * 2014-03-27 2015-10-01 三洋電機株式会社 Non-aqueous electrolyte secondary battery
CN106165180A (en) * 2014-03-27 2016-11-23 三洋电机株式会社 Rechargeable nonaqueous electrolytic battery
JPWO2015146024A1 (en) * 2014-03-27 2017-04-13 三洋電機株式会社 Nonaqueous electrolyte secondary battery
US10096829B2 (en) 2014-03-27 2018-10-09 Sanyo Electric Co., Ltd. Nonaqueous electrolyte secondary batteries
CN106165180B (en) * 2014-03-27 2019-11-22 三洋电机株式会社 Non-aqueous electrolyte secondary battery
WO2017175697A1 (en) * 2016-04-04 2017-10-12 株式会社Ｇｓユアサ Power storage element
CN109075310A (en) * 2016-04-04 2018-12-21 株式会社杰士汤浅国际 Charge storage element
JPWO2017175697A1 (en) * 2016-04-04 2019-02-14 株式会社Ｇｓユアサ Electricity storage element
US11217782B2 (en) 2016-04-04 2022-01-04 Gs Yuasa International Ltd. Energy storage device
JP7054479B2 (en) 2016-04-04 2022-04-14 株式会社Ｇｓユアサ Power storage element

Similar Documents

Publication Publication Date Title
JP5882516B2 (en) Lithium secondary battery
WO2009141991A1 (en) Electrode for non-aqueous electrolyte secondary battery, manufacturing method therefor, and non-aqueous electrolyte secondary battery
JP4834030B2 (en) Positive electrode for lithium secondary battery and lithium secondary battery using the same
WO2013080379A1 (en) Lithium secondary battery and method for manufacturing same
US20130219703A1 (en) Method for producing composition for forming positive electrode material mixture layer and method for producing lithium ion secondary battery
WO2019216275A1 (en) Positive electrode composition for lithium ion secondary cell, positive electrode for lithium ion secondary cell, and lithium ion secondary cell
KR20110025791A (en) Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using same
CN107660316B (en) Positive electrode of lithium electrochemical power generation device
JP2007234277A (en) Positive electrode for nonaqueous electrolyte secondary battery, its manufacturing method, and nonaqueous electrolyte secondary battery
KR20140083029A (en) Nonaqueous electrolyte secondary battery and use of same
JP2011192561A (en) Manufacturing method for nonaqueous electrolyte secondary battery
CN111052457B (en) Positive electrode for nonaqueous electrolyte battery and nonaqueous electrolyte battery
JP2005294078A (en) Negative electrode for secondary battery, and secondary battery
JP2005197073A (en) Positive electrode for lithium secondary battery
JP5679206B2 (en) Method for producing negative electrode for lithium ion secondary battery and method for producing lithium ion secondary battery
JP2009283353A (en) Electrode for battery, manufacturing method thereof, and battery
JP2011070802A (en) Nonaqueous electrolyte secondary battery
JP2015179608A (en) Negative electrode active material for lithium ion secondary batteries, manufacturing method thereof, and lithium ion secondary battery arranged by use thereof
JP2011134535A (en) Positive electrode for lithium secondary battery, and method for manufacturing the same
CN108963192B (en) Method for producing negative electrode for nonaqueous electrolyte secondary battery and method for producing nonaqueous electrolyte secondary battery
JP4120439B2 (en) Lithium ion secondary battery
JP3981866B2 (en) Method for producing positive electrode for lithium battery and positive electrode for lithium battery
JP5418828B2 (en) Lithium secondary battery and manufacturing method thereof
JPH09306546A (en) Positive electrode plate for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery
JP2010009806A (en) Nonaqueous electrolyte secondary battery