JP2006331937A - Nonaqueous electrolyte secondary battery - Google Patents

Nonaqueous electrolyte secondary battery Download PDF

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JP2006331937A
JP2006331937A JP2005155982A JP2005155982A JP2006331937A JP 2006331937 A JP2006331937 A JP 2006331937A JP 2005155982 A JP2005155982 A JP 2005155982A JP 2005155982 A JP2005155982 A JP 2005155982A JP 2006331937 A JP2006331937 A JP 2006331937A
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positive electrode
mass
pvdf
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Yuichi Ito
裕一 伊藤
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Sanyo Electric Co Ltd
Sanyo GS Soft Energy Co Ltd
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Sanyo GS Soft Energy Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery realizing high energy density and with adhesiveness and plasticity of a cathode mixture improved. <P>SOLUTION: In the nonaqueous electrolyte secondary battery 1 equipped with a cathode plate 4 with a cathode mixture containing carbon black and polyvinylidene fluoride and pressed under 100°C, a ratio of the carbon black to the cathode mixture is to be 1% by mass or more and 3% by mass or less, a ratio of the polyvinylidene fluoride to the cathode mixture 2% by mass or more and 4% by mass or less, and a mass ratio of the carbon black to the polyvinylidene fluoride is to be 0.33 or more and 0.75 or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、カーボンブラック及びポリフッ化ビニリデンを含有する正極合剤を有し、100℃以下でプレスされた正極を備える非水電解質二次電池に関する。   The present invention relates to a non-aqueous electrolyte secondary battery having a positive electrode mixture containing carbon black and polyvinylidene fluoride and having a positive electrode pressed at 100 ° C. or lower.

携帯電話などの携帯電子機器の電源としてリチウムイオン電池などの二次電池が用いられているが、携帯電子機器の高機能化に伴い、二次電池の高エネルギー密度化に対する要求が強くなっている。高エネルギー密度化のためには、例えば正極合剤中の正極活物質の含有率を高める、又は、正極合剤の充填密度を高めることなどが行われる。正極合剤の充填密度を高めるためには、高密度化に適したプレス条件で正極をプレスする必要があり、例えば60℃以上に加熱してプレスを行う方法が提案されている(特許文献1参照)。
特開平10−255763号公報
Secondary batteries such as lithium-ion batteries are used as power sources for portable electronic devices such as mobile phones, but with the enhancement of functionality of portable electronic devices, the demand for higher energy density of secondary batteries has become stronger. . In order to increase the energy density, for example, the content of the positive electrode active material in the positive electrode mixture is increased, or the packing density of the positive electrode mixture is increased. In order to increase the packing density of the positive electrode material mixture, it is necessary to press the positive electrode under pressing conditions suitable for increasing the density. For example, a method of pressing the positive electrode material by heating to 60 ° C. or more has been proposed (Patent Document 1). reference).
Japanese Patent Laid-Open No. 10-255563

しかし、60℃以上に加熱して正極のプレスを行った場合、正極合剤の充填密度は高まるが、正極合剤中のバインダーの接着性が高まるために正極合剤が硬くなり、正極板の柔軟性が低下するという問題が生じる。正極板の柔軟性が低下した場合、正極板に亀裂又は切断が生じ易くなり、電極エレメントの作製時に不良が発生しやすくなる。   However, when the positive electrode is pressed by heating to 60 ° C. or higher, the packing density of the positive electrode mixture increases, but the positive electrode mixture becomes hard because the adhesiveness of the binder in the positive electrode mixture increases, The problem arises that flexibility is reduced. When the flexibility of the positive electrode plate is lowered, the positive electrode plate is likely to be cracked or cut, and defects are likely to occur during the production of the electrode element.

本発明は斯かる事情に鑑みてなされたものであり、正極が100℃以下でプレスされており、正極合剤に対するカーボンブラックの割合が1質量%以上3質量%以下であり、正極合剤に対するポリフッ化ビニリデンの割合が2質量%以上4質量%以下であり、ポリフッ化ビニリデンに対するカーボンブラックの質量比が0.33以上0.75以下であることにより、正極合剤の密着性及び柔軟性を向上させると共に高エネルギー密度の非水電解質二次電池を提供することを目的とする。   This invention is made | formed in view of such a situation, The positive electrode is pressed at 100 degrees C or less, The ratio of the carbon black with respect to a positive mix is 1 to 3 mass%, and with respect to a positive mix When the ratio of polyvinylidene fluoride is 2% by mass or more and 4% by mass or less, and the mass ratio of carbon black to polyvinylidene fluoride is 0.33 or more and 0.75 or less, the adhesion and flexibility of the positive electrode mixture can be improved. An object of the present invention is to provide a non-aqueous electrolyte secondary battery with improved energy density.

また、本発明は、70℃以上の温度でプレスされた正極を用いることにより、プレス回数を減少させ、正極の生産効率を向上させた非水電解質二次電池を提供することを他の目的とする。   Another object of the present invention is to provide a nonaqueous electrolyte secondary battery in which the number of presses is reduced and the production efficiency of the positive electrode is improved by using a positive electrode pressed at a temperature of 70 ° C. or higher. To do.

また、本発明は、カーボンブラックとしてアセチレンブラックを用いることにより、高率放電特性の向上を図ることができる非水電解質二次電池を提供することを他の目的とする。   Another object of the present invention is to provide a non-aqueous electrolyte secondary battery capable of improving high rate discharge characteristics by using acetylene black as carbon black.

第1発明に係る非水電解質二次電池は、カーボンブラック及びポリフッ化ビニリデンを含有する正極合剤を有し、100℃以下でプレスされた正極を備える非水電解質二次電池において、前記正極合剤に対する前記カーボンブラックの割合が1質量%以上3質量%以下であり、前記正極合剤に対する前記ポリフッ化ビニリデンの割合が2質量%以上4質量%以下であり、前記ポリフッ化ビニリデンに対する前記カーボンブラックの質量比が0.33以上0.75以下であることを特徴とする。   The non-aqueous electrolyte secondary battery according to the first aspect of the present invention is a non-aqueous electrolyte secondary battery having a positive electrode mixture containing carbon black and polyvinylidene fluoride, and comprising a positive electrode pressed at 100 ° C. or lower. The ratio of the carbon black to the agent is 1% by mass to 3% by mass, the ratio of the polyvinylidene fluoride to the positive electrode mixture is 2% to 4% by mass, and the carbon black to the polyvinylidene fluoride The mass ratio is 0.33 or more and 0.75 or less.

第2発明に係る非水電解質二次電池は、カーボンブラック及びポリフッ化ビニリデンを含有する正極合剤を有し、70℃以上100℃以下でプレスされた正極を備える非水電解質二次電池において、前記正極合剤に対する前記カーボンブラックの割合が1質量%以上3質量%以下であり、前記正極合剤に対する前記ポリフッ化ビニリデンの割合が2質量%以上4質量%以下であり、前記ポリフッ化ビニリデンに対する前記カーボンブラックの質量比が0.33以上0.75以下であることを特徴とする。   A non-aqueous electrolyte secondary battery according to a second invention has a positive electrode mixture containing carbon black and polyvinylidene fluoride, and includes a positive electrode pressed at 70 ° C. or higher and 100 ° C. or lower. The ratio of the carbon black to the positive electrode mixture is 1% by mass or more and 3% by mass or less, the ratio of the polyvinylidene fluoride to the positive electrode mixture is 2% by mass or more and 4% by mass or less, and relative to the polyvinylidene fluoride. The mass ratio of the carbon black is 0.33 or more and 0.75 or less.

第3発明に係る非水電解質二次電池は、第1又は第2発明において、前記カーボンブラックは、アセチレンブラックを含むことを特徴とする。   The non-aqueous electrolyte secondary battery according to a third aspect of the present invention is characterized in that, in the first or second aspect, the carbon black contains acetylene black.

第1発明においては、正極合剤に対するカーボンブラックの割合は、1質量%未満では導電性が不十分であるために高率放電特性が低下し、3質量%超では活物質の含有率が低下して電池容量の高密度化の妨げになるため、1質量%以上3質量%以下にしてエネルギー密度を高める。また、正極合剤に対するポリフッ化ビニリデンの割合は、2質量%未満では正極合剤の密着性が不十分であるために正極合剤の剥離などが生じ、4質量%を超える場合は活物質の含有率が低下するために電池容量の高密度化の妨げになることに加え、正極合剤の抵抗が高くなるために電池の高率放電特性が低下するため、2質量%以上4質量%以下にしてエネルギー密度及び正極合剤の密着性を高める。さらに、ポリフッ化ビニリデンに対するカーボンブラックの質量比は、0.33未満の場合は正極板の導電性が不足するために電池の高率放電特性が低下し、0.75を超える場合は正極合剤の密着性が低下するため、0.33以上0.75以下にしてエネルギー密度及び正極合剤の密着性を高める。正極板のプレス時の温度は、100℃を超える場合は正極板の柔軟性が大幅に低下し、正極板及び負極板を巻回して電極エレメントを作製する際などに正極板の切断又は亀裂などの不具合が生じるため、100℃以下にして正極合剤の柔軟性を高める。これにより、正極合剤の密着性及び柔軟性を向上させると共に高エネルギー密度の非水電解質二次電池を製造することができる。   In the first invention, if the ratio of carbon black to the positive electrode mixture is less than 1% by mass, the electrical conductivity is insufficient, so that the high rate discharge characteristic is lowered, and if it exceeds 3% by mass, the content of the active material is lowered. In order to prevent the battery capacity from being increased, the energy density is increased to 1% by mass or more and 3% by mass or less. Further, when the proportion of polyvinylidene fluoride with respect to the positive electrode mixture is less than 2% by mass, the adhesion of the positive electrode mixture is insufficient, and the positive electrode mixture is peeled off. 2% by mass or more and 4% by mass or less because the high rate discharge characteristic of the battery is deteriorated because the resistance of the positive electrode mixture is increased in addition to hindering the high density of the battery capacity due to the decrease in the content rate. Thus, the energy density and the adhesion of the positive electrode mixture are increased. Further, when the mass ratio of carbon black to polyvinylidene fluoride is less than 0.33, the high-rate discharge characteristics of the battery are deteriorated due to insufficient conductivity of the positive electrode plate, and when it exceeds 0.75, the positive electrode mixture Therefore, the energy density and the adhesion of the positive electrode mixture are improved. When the temperature at the time of pressing the positive electrode plate exceeds 100 ° C., the flexibility of the positive electrode plate is greatly reduced, and the positive electrode plate is cut or cracked when the positive electrode plate and the negative electrode plate are wound to produce an electrode element. Therefore, the flexibility of the positive electrode mixture is increased to 100 ° C. or lower. Thereby, the adhesiveness and flexibility of the positive electrode mixture can be improved, and a high energy density non-aqueous electrolyte secondary battery can be manufactured.

第2発明においては、正極が70℃以上の温度でプレスされているため、正極合剤に含まれるバインダーが軟化するため、プレス時の応力が低下し、プレス回数を減少でき、正極の生産効率が向上する。   In the second invention, since the positive electrode is pressed at a temperature of 70 ° C. or higher, the binder contained in the positive electrode mixture is softened, so the stress during pressing is reduced, the number of presses can be reduced, and the positive electrode production efficiency. Will improve.

第3発明においては、アセチレンブラックは導電性に優れており、カーボンブラックとしてアセチレンブラックを用いることにより、少量でも良好な導電性を得て高率放電特性を向上させることができる。   In the third invention, acetylene black is excellent in conductivity, and by using acetylene black as carbon black, good conductivity can be obtained even in a small amount and high-rate discharge characteristics can be improved.

第1発明によれば、正極合剤の密着性及び柔軟性を向上させると共に高エネルギー密度の非水電解質二次電池を製造することができる。   According to the first invention, it is possible to improve the adhesion and flexibility of the positive electrode mixture and to manufacture a non-aqueous electrolyte secondary battery having a high energy density.

第2発明によれば、正極のプレス回数を減少でき、生産効率が向上する。   According to the second invention, the number of positive electrode pressings can be reduced, and the production efficiency is improved.

第3発明によれば、高率放電特性の向上を図ることができる。   According to the third invention, it is possible to improve the high rate discharge characteristics.

以下、本発明をその実施の形態を示す図面に基づいて具体的に説明する。なお、本実施例に記載した正極、負極、電解液、セパレータ、及び電池の作成方法などは一例であり、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 the drawings showing embodiments thereof. In addition, the positive electrode, negative electrode, electrolyte solution, separator, production method of a battery, etc. which were described in the present Example are examples, and do not limit this invention.

(実施例1)
図1は、本発明に係る非水電解質二次電池の概略構成を示す断面図である。非水電解質二次電池(以下、電池という)1は、銅集電体に負極合剤が塗布されている負極板3及びアルミ集電体に正極合剤が塗布されている正極板4をセパレータ5を介して扁平巻状に巻回した電極エレメント2と、電極エレメント2及び非水電解液(電解質)を収納する角型の電池ケース6と、電池ケース6の開口部にレーザー溶接される電池蓋7とを備える。電池蓋7は安全弁8及び負極端子9を有し、負極端子9は負極リード10を介して負極板3に接続されている。また、正極板4は、電池ケース6の内面と電気的に接続されている。電池のサイズは、幅30mm、高さ48mm、厚さ4.2mmであり、放電容量は600mAhである。
Example 1
FIG. 1 is a cross-sectional view showing a schematic configuration of a nonaqueous electrolyte secondary battery according to the present invention. A non-aqueous electrolyte secondary battery (hereinafter referred to as a battery) 1 includes a negative electrode plate 3 in which a negative electrode mixture is applied to a copper current collector and a positive electrode plate 4 in which a positive electrode mixture is applied to an aluminum current collector. 5, the electrode element 2 wound in a flat winding shape via 5, the rectangular battery case 6 that houses the electrode element 2 and the nonaqueous electrolyte (electrolyte), and the battery that is laser welded to the opening of the battery case 6 And a lid 7. The battery lid 7 has a safety valve 8 and a negative electrode terminal 9, and the negative electrode terminal 9 is connected to the negative electrode plate 3 through a negative electrode lead 10. The positive electrode plate 4 is electrically connected to the inner surface of the battery case 6. The battery has a width of 30 mm, a height of 48 mm, a thickness of 4.2 mm, and a discharge capacity of 600 mAh.

正極板4については、正極活物質として、酸化コバルト(Co3 4 )と炭酸リチウム(Li2 CO3 )とを、リチウムとコバルトとのモル比が1:1となるように混合した後、950℃で3時間焼成し、コバルト酸リチウム(LiCoO2 )を得た。この正極活物質97質量%と、導電剤であるカーボンブラックとしてアセチレンブラック(AB)1質量%と、バインダーとしてポリフッ化ビニリデン(PVDF)2質量%とを混合した正極合剤に、溶媒であるN−メチル−2−ピロリドン(NMP)を適量加えて攪拌することで、正極ペーストを調製した。この正極ペーストを、NMPを取除いた合剤の質量が片面につき0.025g/cm2 となるように、ドクターブレードを用いて厚さ15μmのアルミ箔集電体の両面に塗布し、乾燥させ、厚さ175μmとなるように70℃で1回プレスして、正極板4を作製した。ここで、アセチレンブラック(AB)として、BET比表面積が約70m2 /gである電気化学工業社製の粒状アセチレンブラックを用いている。また、PVDFに対するABの質量比(AB/PVDF)は0.5である。 The positive electrode plate 4, as a positive electrode active material, a cobalt oxide (Co 3 O 4) and lithium carbonate (Li 2 CO 3), the molar ratio of lithium and cobalt is 1: After mixing to be 1, Calcination was performed at 950 ° C. for 3 hours to obtain lithium cobalt oxide (LiCoO 2 ). A positive electrode mixture obtained by mixing 97% by mass of the positive electrode active material, 1% by mass of acetylene black (AB) as carbon black as a conductive agent, and 2% by mass of polyvinylidene fluoride (PVDF) as a binder is added to N as a solvent. A positive electrode paste was prepared by adding an appropriate amount of methyl-2-pyrrolidone (NMP) and stirring. This positive electrode paste was applied to both sides of an aluminum foil current collector having a thickness of 15 μm using a doctor blade so that the mass of the mixture from which NMP was removed was 0.025 g / cm 2 per side and dried. Then, pressing was performed once at 70 ° C. so as to have a thickness of 175 μm, and the positive electrode plate 4 was produced. Here, granular acetylene black made by Denki Kagaku Kogyo Co., Ltd. having a BET specific surface area of about 70 m 2 / g is used as acetylene black (AB). Moreover, the mass ratio of AB to PVDF (AB / PVDF) is 0.5.

負極板3については、負極活物質としてグラファイト(黒鉛)及びバインダーとしてポリフッ化ビニリデン(PVDF)を質量比で90:10とした負極合材に、N−メチル−2−ピロリドン(NMP)を適量加えて負極ペーストを調製した。この負極ペーストを、NMPを取除いた合剤の質量が片面につき0.012g/cm2 となるように、ドクターブレードを用いて厚さ10μmの銅箔集電体の両面に塗布し、乾燥させ、厚さ175μmとなるようにプレスして、負極板3を作製した。 For the negative electrode plate 3, an appropriate amount of N-methyl-2-pyrrolidone (NMP) was added to the negative electrode mixture in which graphite (graphite) as the negative electrode active material and polyvinylidene fluoride (PVDF) as the binder were 90:10 in mass ratio. A negative electrode paste was prepared. This negative electrode paste was applied to both sides of a 10 μm thick copper foil current collector using a doctor blade so that the mass of the mixture with NMP removed was 0.012 g / cm 2 per side and dried. The negative electrode plate 3 was manufactured by pressing to a thickness of 175 μm.

セパレータには、ポリエチレン製微多孔膜を用いた。電解液(電解質)には、エチレンカーボネート(EC):ジエチルカーボネート(DEC)=3:7(体積比)の混合溶媒にLiPF6 を1mol/l溶解させたものを用いた。 A polyethylene microporous film was used as the separator. As the electrolytic solution (electrolyte), a solution obtained by dissolving 1 mol / l of LiPF 6 in a mixed solvent of ethylene carbonate (EC): diethyl carbonate (DEC) = 3: 7 (volume ratio) was used.

(実施例2)
正極作製時のプレス温度を100℃とし、それ以外は実施例1と同様の電池を作製した。
(Example 2)
A battery was manufactured in the same manner as in Example 1 except that the press temperature during the production of the positive electrode was 100 ° C.

(実施例3)
正極活物質96質量%とアセチレンブラック(AB)1質量%とポリフッ化ビニリデン(PVDF)3質量%とを混合した正極合剤(AB/PVDF=0.33)を用い、それ以外は実施例1と同様の電池を作製した。
(Example 3)
Example 1 except that a positive electrode mixture (AB / PVDF = 0.33) in which 96% by mass of a positive electrode active material, 1% by mass of acetylene black (AB) and 3% by mass of polyvinylidene fluoride (PVDF) were mixed was used. A similar battery was produced.

(実施例4)
正極作製時のプレス温度を100℃とし、それ以外は実施例3と同様の電池を作製した。
Example 4
A battery was manufactured in the same manner as in Example 3 except that the press temperature during the production of the positive electrode was 100 ° C.

(実施例5)
正極活物質95質量%とAB2質量%とPVDF3質量%とを混合した正極合剤(AB/PVDF=0.67)を用い、それ以外は実施例1と同様の電池を作製した。
(Example 5)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.67) in which 95% by mass of the positive electrode active material, 2% by mass of AB, and 3% by mass of PVDF were mixed was used.

(実施例6)
正極作製時のプレス温度を100℃とし、それ以外は実施例5と同様の電池を作製した。
(Example 6)
A battery was manufactured in the same manner as in Example 5 except that the press temperature during the production of the positive electrode was 100 ° C.

(実施例7)
正極活物質94質量%とAB2質量%とPVDF4質量%とを混合した正極合剤(AB/PVDF=0.50)を用い、それ以外は実施例1と同様の電池を作製した。
(Example 7)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.50) in which 94% by mass of the positive electrode active material, 2% by mass of AB, and 4% by mass of PVDF were mixed was used.

(実施例8)
正極作製時のプレス温度を100℃とし、それ以外は実施例7と同様の電池を作製した。
(Example 8)
A battery was manufactured in the same manner as in Example 7 except that the press temperature during the production of the positive electrode was 100 ° C.

(実施例9)
正極活物質93質量%とAB3質量%とPVDF4質量%とを混合した正極合剤(AB/PVDF=0.75)を用い、それ以外は実施例1と同様の電池を作製した。
Example 9
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.75) in which 93% by mass of the positive electrode active material, 3% by mass of AB, and 4% by mass of PVDF were mixed was used.

(実施例10)
正極作製時のプレス温度を100℃とし、それ以外は実施例9と同様の電池を作製した。
(Example 10)
A battery was manufactured in the same manner as in Example 9 except that the press temperature during the production of the positive electrode was 100 ° C.

(実施例11)
正極作製時のプレス温度を常温、プレス回数を2回とし、それ以外は実施例1と同様の電池を作製した。
(Example 11)
A battery was manufactured in the same manner as in Example 1 except that the press temperature during the production of the positive electrode was normal temperature and the number of presses was two.

(実施例12)
正極活物質96質量%とAB1質量%とPVDF3質量%とを混合した正極合剤(AB/PVDF=0.33)を用い、正極作製時のプレス温度を常温、プレス回数を2回とし、それ以外は実施例1と同様の電池を作製した。
(Example 12)
Using a positive electrode mixture (AB / PVDF = 0.33) in which 96% by mass of the positive electrode active material, 1% by mass of AB, and 3% by mass of PVDF were mixed, the press temperature at the time of producing the positive electrode was room temperature and the number of presses was 2 times. A battery was prepared in the same manner as in Example 1 except for the above.

(実施例13)
正極活物質95質量%とAB2質量%とPVDF3質量%とを混合した正極合剤(AB/PVDF=0.67)を用い、正極作製時のプレス温度を常温、プレス回数を2回とし、それ以外は実施例1と同様の電池を作製した。
(Example 13)
Using a positive electrode mixture (AB / PVDF = 0.67) in which 95% by mass of the positive electrode active material, 2% by mass of AB, and 3% by mass of PVDF were mixed, A battery was prepared in the same manner as in Example 1 except for the above.

(実施例14)
正極活物質94質量%とAB2質量%とPVDF4質量%とを混合した正極合剤(AB/PVDF=0.50)を用い、正極作製時のプレス温度を常温、プレス回数を2回とし、それ以外は実施例1と同様の電池を作製した。
(Example 14)
Using a positive electrode mixture (AB / PVDF = 0.50) in which 94% by mass of the positive electrode active material, 2% by mass of AB, and 4% by mass of PVDF are mixed, the press temperature at the time of producing the positive electrode is room temperature and the number of presses is 2 times. A battery was prepared in the same manner as in Example 1 except for the above.

(実施例15)
正極活物質93質量%とAB3質量%とPVDF4質量%とを混合した正極合剤(AB/PVDF=0.75)を用い、正極作製時のプレス温度を常温、プレス回数を2回とし、それ以外は実施例1と同様の電池を作製した。
(Example 15)
Using a positive electrode mixture (AB / PVDF = 0.75) in which 93% by mass of the positive electrode active material, 3% by mass of AB, and 4% by mass of PVDF were mixed, A battery was prepared in the same manner as in Example 1 except for the above.

(比較例1)
正極活物質99質量%とAB0.5質量%とPVDF0.5質量%とを混合した正極合剤(AB/PVDF=1.00)を用い、正極作製時のプレス温度を常温、プレス回数を2回とし、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 1)
Using a positive electrode mixture (AB / PVDF = 1.00) in which 99% by mass of the positive electrode active material, 0.5% by mass of AB, and 0.5% by mass of PVDF are mixed, the press temperature at the time of producing the positive electrode is normal temperature and the number of presses is 2. Otherwise, a battery similar to that of Example 1 was produced.

(比較例2)
正極作製時のプレス温度を70℃、プレス回数を1回とし、それ以外は比較例1と同様の電池を作製した。
(Comparative Example 2)
A battery was manufactured in the same manner as in Comparative Example 1 except that the press temperature during the production of the positive electrode was 70 ° C. and the number of presses was one.

(比較例3)
正極作製時のプレス温度を100℃、プレス回数を1回とし、それ以外は比較例1と同様の電池を作製した。
(Comparative Example 3)
A battery was manufactured in the same manner as in Comparative Example 1 except that the press temperature during the production of the positive electrode was 100 ° C. and the number of presses was one.

(比較例4)
正極作製時のプレス温度を110℃、プレス回数を1回とし、それ以外は比較例1と同様の電池を作製した。
(Comparative Example 4)
A battery was manufactured in the same manner as in Comparative Example 1 except that the press temperature during the production of the positive electrode was 110 ° C. and the number of presses was one.

(比較例5)
正極活物質98.5質量%とAB0.5質量%とPVDF1質量%とを混合した正極合剤(AB/PVDF=0.50)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 5)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.50) in which 98.5% by mass of the positive electrode active material, 0.5% by mass of AB, and 1% by mass of PVDF were mixed was used. .

(比較例6)
正極作製時のプレス温度を100℃とし、それ以外は比較例5と同様の電池を作製した。
(Comparative Example 6)
A battery was manufactured in the same manner as in Comparative Example 5 except that the press temperature during the production of the positive electrode was 100 ° C.

(比較例7)
正極作製時のプレス温度を110℃とし、それ以外は比較例5と同様の電池を作製した。
(Comparative Example 7)
A battery was manufactured in the same manner as in Comparative Example 5 except that the press temperature during the production of the positive electrode was 110 ° C.

(比較例8)
正極活物質97.5質量%とAB0.5質量%とPVDF2質量%とを混合した正極合剤(AB/PVDF=0.25)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 8)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.25) in which 97.5% by mass of the positive electrode active material, 0.5% by mass of AB, and 2% by mass of PVDF were mixed was used. .

(比較例9)
正極活物質98質量%とAB1質量%とPVDF1質量%とを混合した正極合剤(AB/PVDF=1.00)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 9)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 1.00) in which 98% by mass of the positive electrode active material, 1% by mass of AB, and 1% by mass of PVDF were mixed was used.

(比較例10)
正極作製時のプレス温度を100℃とし、それ以外は比較例9と同様の電池を作製した。
(Comparative Example 10)
A battery was manufactured in the same manner as in Comparative Example 9 except that the press temperature during the production of the positive electrode was 100 ° C.

(比較例11)
正極作製時のプレス温度を110℃とし、それ以外は比較例9と同様の電池を作製した。
(Comparative Example 11)
A battery was manufactured in the same manner as in Comparative Example 9 except that the press temperature during the production of the positive electrode was 110 ° C.

(比較例12)
正極作製時のプレス温度を110℃とし、プレス回数を1回とし、それ以外は実施例11と同様の電池を作製した。
(Comparative Example 12)
A battery was manufactured in the same manner as in Example 11 except that the press temperature during the production of the positive electrode was 110 ° C., the number of presses was one, and the other.

(比較例13)
正極作製時のプレス温度を110℃とし、プレス回数を1回とし、それ以外は実施例12と同様の電池を作製した。
(Comparative Example 13)
A battery was manufactured in the same manner as in Example 12 except that the press temperature during the production of the positive electrode was 110 ° C. and the number of presses was one.

(比較例14)
正極活物質95質量%とAB1質量%とPVDF4質量%とを混合した正極合剤(AB/PVDF=0.25)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 14)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.25) in which 95% by mass of the positive electrode active material, 1% by mass of AB, and 4% by mass of PVDF were mixed was used.

(比較例15)
正極活物質96質量%とAB2質量%とPVDF2質量%とを混合した正極合剤(AB/PVDF=1.00)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 15)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 1.00) in which 96% by mass of the positive electrode active material, 2% by mass of AB, and 2% by mass of PVDF were mixed was used.

(比較例16)
正極作製時のプレス温度を100℃とし、それ以外は比較例15と同様の電池を作製した。
(Comparative Example 16)
A battery was manufactured in the same manner as in Comparative Example 15 except that the press temperature during the production of the positive electrode was 100 ° C.

(比較例17)
正極作製時のプレス温度を110℃とし、それ以外は比較例15と同様の電池を作製した。
(Comparative Example 17)
A battery was manufactured in the same manner as in Comparative Example 15 except that the press temperature during the production of the positive electrode was 110 ° C.

(比較例18)
正極作製時のプレス温度を110℃、プレス回数を1回とし、それ以外は実施例13と同様の電池を作製した。
(Comparative Example 18)
A battery was manufactured in the same manner as in Example 13 except that the press temperature during the production of the positive electrode was 110 ° C. and the number of presses was one.

(比較例19)
正極作製時のプレス温度を110℃、プレス回数を1回とし、それ以外は実施例14と同様の電池を作製した。
(Comparative Example 19)
A battery was manufactured in the same manner as in Example 14 except that the press temperature during the production of the positive electrode was 110 ° C. and the number of presses was one.

(比較例20)
正極活物質93質量%とAB2質量%とPVDF5質量%とを混合した正極合剤(AB/PVDF=0.40)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 20)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.40) in which 93% by mass of the positive electrode active material, 2% by mass of AB, and 5% by mass of PVDF were mixed was used.

(比較例21)
正極活物質94質量%とAB3質量%とPVDF3質量%とを混合した正極合剤(AB/PVDF=1.00)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 21)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 1.00) in which 94% by mass of the positive electrode active material, 3% by mass of AB, and 3% by mass of PVDF were mixed was used.

(比較例22)
正極作製時のプレス温度を100℃とし、それ以外は比較例21と同様の電池を作製した。
(Comparative Example 22)
A battery was manufactured in the same manner as in Comparative Example 21 except that the press temperature during the production of the positive electrode was 100 ° C.

(比較例23)
正極作製時のプレス温度を110℃とし、それ以外は比較例21と同様の電池を作製した。
(Comparative Example 23)
A battery was manufactured in the same manner as in Comparative Example 21 except that the press temperature during the production of the positive electrode was 110 ° C.

(比較例24)
正極作製時のプレス温度を110℃、プレス回数を1回とし、それ以外は実施例15と同様の電池を作製した。
(Comparative Example 24)
A battery was manufactured in the same manner as in Example 15 except that the press temperature during the production of the positive electrode was 110 ° C. and the number of presses was one.

(比較例25)
正極活物質92質量%とAB3質量%とPVDF5質量%とを混合した正極合剤(AB/PVDF=0.60)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 25)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.60) in which 92% by mass of the positive electrode active material, 3% by mass of AB, and 5% by mass of PVDF were mixed was used.

(比較例26)
正極活物質92質量%とAB4質量%とPVDF4質量%とを混合した正極合剤(AB/PVDF=1.00)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 26)
A battery was prepared in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 1.00) in which 92% by mass of the positive electrode active material, 4% by mass of AB, and 4% by mass of PVDF were mixed was used.

(比較例27)
正極作製時のプレス温度を100℃とし、それ以外は比較例26と同様の電池を作製した。
(Comparative Example 27)
A battery was produced in the same manner as in Comparative Example 26 except that the press temperature during the production of the positive electrode was 100 ° C.

(比較例28)
正極作製時のプレス温度を110℃とし、それ以外は比較例26と同様の電池を作製した。
(Comparative Example 28)
A battery was manufactured in the same manner as in Comparative Example 26 except that the press temperature during the production of the positive electrode was 110 ° C.

(比較例29)
正極活物質91質量%とAB4質量%とPVDF5質量%とを混合した正極合剤(AB/PVDF=0.80)を用い、それ以外は実施例1と同様の電池を作製した。
(Comparative Example 29)
A battery was manufactured in the same manner as in Example 1 except that a positive electrode mixture (AB / PVDF = 0.80) in which 91% by mass of the positive electrode active material, 4% by mass of AB, and 5% by mass of PVDF were mixed was used.

(比較例30)
正極作製時のプレス温度を100℃とし、それ以外は比較例29と同様の電池を作製した。
(Comparative Example 30)
A battery was manufactured in the same manner as in Comparative Example 29 except that the press temperature during the production of the positive electrode was 100 ° C.

(比較例31)
正極作製時のプレス温度を110℃とし、それ以外は比較例29と同様の電池を作製した。
(Comparative Example 31)
A battery was produced in the same manner as in Comparative Example 29 except that the press temperature during the production of the positive electrode was 110 ° C.

上述した実施例及び比較例の正極板について、正極合剤の密着性、及び、正極板の柔軟性の評価を行った。また、上述した実施例及び比較例の電池の高率放電特性の評価を行った。正極合剤の密着性の評価については、電極エレメント2の幅に合わせて正極板4のスリット(切断)を行う際に、正極合剤の一部が剥離又は脱落したものについては、電池を作成した際に内部短絡が生じる原因となるため、不良とみなした。試験数は各実施例及び各比較例の正極板に対して10個とし、そのうちの一つにでも剥離又は脱落が認められた場合は不良とみなした。また、スリット時に正極合材の剥離又は脱落が生じた比較例については、電極エレメント2は作製しておらず、正極板の柔軟性の評価及び高率放電特性の評価は行っていない。   About the positive electrode plate of the Example mentioned above and the comparative example, the adhesiveness of the positive electrode mixture and the softness | flexibility of the positive electrode plate were evaluated. Moreover, the high-rate discharge characteristics of the batteries of the above-described examples and comparative examples were evaluated. Regarding the evaluation of the adhesion of the positive electrode mixture, a battery was prepared for the case where a part of the positive electrode mixture was peeled off or dropped when the positive electrode plate 4 was slit (cut) in accordance with the width of the electrode element 2. It was regarded as defective because it caused an internal short circuit. The number of tests was 10 with respect to the positive electrode plates of each Example and each Comparative Example, and when any one of them was peeled or dropped, it was regarded as defective. Moreover, about the comparative example in which peeling or dropping of the positive electrode mixture occurred at the time of slitting, the electrode element 2 was not manufactured, and the evaluation of the flexibility of the positive electrode plate and the evaluation of the high rate discharge characteristics were not performed.

正極板4の柔軟性の評価については、正極合剤の密着性の評価に問題が無い場合、セパレータ5を介して正極板4及び負極板3を巻回して電極エレメント2を作製し、折り曲げられる角度がもっとも大きい最内周部の正極板4の切断又は亀裂の有無を確認した。試験数は各実施例及び各比較例の正極板に対して10個とし、そのうちの一つにでも切断又は亀裂が認められた場合は不良とみなした。また、電極エレメント2を作成する際に正極板4に切断又は亀裂が生じた比較例については、電池は作製しておらず、高率放電特性の評価は行っていない。   Regarding the evaluation of the flexibility of the positive electrode plate 4, when there is no problem in the evaluation of the adhesion of the positive electrode mixture, the positive electrode plate 4 and the negative electrode plate 3 are wound through the separator 5 to produce the electrode element 2 and bent. Whether the innermost peripheral positive electrode plate 4 having the largest angle was cut or cracked was confirmed. The number of tests was 10 with respect to the positive electrode plates of each Example and each Comparative Example, and when any one of them was found to have a cut or crack, it was considered defective. Moreover, about the comparative example by which the positive electrode plate 4 was cut | disconnected or cracked when producing the electrode element 2, the battery was not produced and the high rate discharge characteristic was not evaluated.

高率放電特性の評価については、正極板4の柔軟性の評価に問題が無い場合、室温20℃の雰囲気下において、充電電流600mA、充電電圧4.20Vの定電流定電圧で2.5時間充電した後、放電電流1CmA(=600mA)、終止電圧2.75Vの条件で放電を行い、放電容量を測定した。また、同一の電池を用いて、放電電流を2CmA(=1200mA)とした高率放電時の放電容量を測定した。なお、試験電池数は、各実施例及び各比較例に対して3個とし、3個の平均値を求めた。また、2CmAの放電容量は、420mAhより低い場合は不良と見なした。各評価の結果を表1,2,3に示す。   As for the evaluation of the high rate discharge characteristics, when there is no problem in the evaluation of the flexibility of the positive electrode plate 4, it is 2.5 hours at a constant current and a constant voltage of a charging current of 600 mA and a charging voltage of 4.20 V in an atmosphere at a room temperature of 20 ° C. After charging, discharge was performed under the conditions of a discharge current of 1 CmA (= 600 mA) and a final voltage of 2.75 V, and the discharge capacity was measured. Further, using the same battery, the discharge capacity during high rate discharge with a discharge current of 2 CmA (= 1200 mA) was measured. The number of test batteries was 3 for each example and each comparative example, and the average value of 3 was obtained. Further, when the discharge capacity of 2 CmA was lower than 420 mAh, it was regarded as defective. The results of each evaluation are shown in Tables 1, 2, and 3.

Figure 2006331937
Figure 2006331937

Figure 2006331937
Figure 2006331937

Figure 2006331937
Figure 2006331937

アセチレンブラック(AB)の含有率が0.5質量%、ポリフッ化ビニリデン(PVDF)の含有率が0.5質量%である比較例1〜4、ABの含有率が0.5質量%、PVDFの含有率が1.0質量%である比較例5〜7、及び、ABの含有率が1.0質量%、PVDFの含有率が1.0質量%である比較例9〜11では、何れのプレス温度でも正極合剤の剥離が生じた。一方、ABの含有率が0.5質量%、PVDFの含有率が2.0質量%(AB/PVDFは0.25)である比較例8では、プレス温度70℃における正極合剤の剥離は生じなかった。よって、正極合剤の密着性を確保するためには、2.0質量%以上のPVDFが必要であると考えられる。   Comparative Examples 1 to 4 in which the content of acetylene black (AB) is 0.5% by mass, the content of polyvinylidene fluoride (PVDF) is 0.5% by mass, the content of AB is 0.5% by mass, PVDF In Comparative Examples 5 to 7 in which the content ratio is 1.0 mass%, and in Comparative Examples 9 to 11 in which the AB content ratio is 1.0 mass% and the PVDF content ratio is 1.0 mass%, The positive electrode mixture was peeled off even at the press temperature. On the other hand, in Comparative Example 8 where the AB content is 0.5% by mass and the PVDF content is 2.0% by mass (AB / PVDF is 0.25), peeling of the positive electrode mixture at a press temperature of 70 ° C. Did not occur. Therefore, in order to ensure the adhesion of the positive electrode mixture, it is considered that 2.0% by mass or more of PVDF is necessary.

しかし、ABの含有率が2.0質量%、PVDFの含有率が2.0質量%(AB/PVDFは1.0)である比較例15〜17、ABの含有率が3.0質量%、PVDFの含有率が3.0質量%(AB/PVDFは1.0)である比較例21〜23、ABの含有率が4.0質量%、PVDFの含有率が4.0質量%(AB/PVDFは1.0)の比較例26〜28、及び、ABの含有率が4.0質量%、PVDFの含有率が5.0質量%(AB/PVDは0.80)である比較例29〜31では、何れのプレス温度でも正極合剤の剥離が生じた。   However, the AB content is 2.0% by mass, the PVDF content is 2.0% by mass (AB / PVDF is 1.0), and the AB content is 3.0% by mass. Comparative Examples 21 to 23 having a PVDF content of 3.0% by mass (AB / PVDF is 1.0), an AB content of 4.0% by mass, and a PVDF content of 4.0% by mass ( AB / PVDF is 1.0) Comparative Examples 26 to 28, and the AB content is 4.0% by mass and the PVDF content is 5.0% by mass (AB / PVD is 0.80) In Examples 29 to 31, peeling of the positive electrode mixture occurred at any pressing temperature.

一方、PVDFが2.0質量%以上で、質量比AB/PVDFが0.75以下である実施例1〜15、比較例8、12〜14、18〜20、24、25では、正極合剤の剥離は生じていない。これは、PVDFの含有量が多い(2.0質量%以上)場合であっても、ABの含有量が多いときは、PVDFの多くが、多量に含まれる嵩高い(充填密度の低い)ABに吸着される、又は、その接着に用いられるために、正極活物質あるいは集電体のアルミ箔との接着に必要なPVDFが不足し、正極合剤とアルミ箔との密着性が低下するためであると考えられる。よって、正極合剤の密着性を確保するためには、PVDFの含有率を2.0質量%以上、AB/PVDFを0.75以下とする必要がある。   On the other hand, in Examples 1 to 15 and Comparative Examples 8, 12 to 14, 18 to 20, 24, and 25 where PVDF is 2.0% by mass or more and mass ratio AB / PVDF is 0.75 or less, a positive electrode mixture No peeling occurred. Even when the content of PVDF is large (2.0% by mass or more), when the content of AB is large, a large amount of PVDF is bulky (low packing density) AB. PVDF necessary for bonding the positive electrode active material or current collector to the aluminum foil is insufficient, and the adhesion between the positive electrode mixture and the aluminum foil is reduced. It is thought that. Therefore, in order to ensure the adhesion of the positive electrode mixture, it is necessary that the PVDF content is 2.0 mass% or more and AB / PVDF is 0.75 or less.

しかし、質量比AB/PVDFが0.75以下であっても、PVDFの含有率が5.0質量%である比較例20、25の電池の高率放電特性(2cmAの放電容量)は大きく低下している。これは絶縁体であるPVDFの絶対量が多いために正極活物質の含有比率が小さくなり、2CmAの放電容量が低下したと考えられる。よって、高率放電特性(放電容量)を良好なものとするためには、PVDFの含有量は4.0質量%以下とする必要がある。   However, even when the mass ratio AB / PVDF is 0.75 or less, the high rate discharge characteristics (discharge capacity of 2 cmA) of the batteries of Comparative Examples 20 and 25 in which the PVDF content is 5.0% by mass are greatly reduced. is doing. This is considered to be because the content ratio of the positive electrode active material was reduced because the absolute amount of PVDF as an insulator was large, and the discharge capacity of 2 CmA was reduced. Therefore, in order to improve the high rate discharge characteristics (discharge capacity), the content of PVDF needs to be 4.0% by mass or less.

PVDFと同様に、AB含有量が多い場合は正極活物質比率が小さくなり、電池容量の高密度化を妨げるため、電池の高密度のためにABの含有量は3.0質量%以下にする必要がある。また、質量比AB/PVDFが0.25である比較例8、14において、2CmAの放電容量が、ABの含有率が0.5質量%である比較例8の電池では107mAh、ABの含有率が1.0質量%である比較例14の電池では323mAhであり、いずれも良好な特性ではなく、特に比較例8は非常に劣っている。また、ABの含有率が1.0質量%、PVDFの含有率が3.0質量%(AB/PVDFは0.33)である実施例3、4の電池の2CmAの放電容量は445〜446mAhと良好である。よって、電池の高率放電特性を良好なものにするために、ABの含有率は1.0質量%以上とし、質量比AB/PVDFは0.33以上とする必要がある。   Similar to PVDF, when the AB content is high, the ratio of the positive electrode active material is reduced, and the battery capacity is prevented from being increased. Therefore, the AB content is set to 3.0% by mass or less for the high density of the battery. There is a need. Further, in Comparative Examples 8 and 14 where the mass ratio AB / PVDF is 0.25, the discharge capacity of 2 CmA is 107 mAh and the AB content in the battery of Comparative Example 8 where the AB content is 0.5 mass%. In the battery of Comparative Example 14 having a content of 1.0 mass%, the current is 323 mAh, none of which is good, and Comparative Example 8 is particularly inferior. Moreover, the discharge capacity of 2 CmA of the batteries of Examples 3 and 4 in which the AB content is 1.0 mass% and the PVDF content is 3.0 mass% (AB / PVDF is 0.33) is 445 to 446 mAh. And good. Therefore, in order to improve the high rate discharge characteristics of the battery, it is necessary that the AB content is 1.0 mass% or more and the mass ratio AB / PVDF is 0.33 or more.

正極板のプレス温度が常温である実施例11〜15の正極板は、所定の厚みにするためにプレスが2回必要であり、製造コストを抑えるという観点から、望ましくない。一方、プレス温度が70℃である実施例1、3、5、7、9の正極板、及びプレス温度が100℃である実施例2、4、6、8、10の正極板は、プレス回数は一回でよい。これは、加熱しながら正極板をプレスすることにより、正極合剤に含まれるPVDFが軟化し、加工性が高まるためであると考えられる。プレス温度は70℃以上が好ましい。なお、プレス温度が70℃よりも低い場合は、常温の場合と殆ど同様であった。   The positive electrode plates of Examples 11 to 15 where the press temperature of the positive electrode plate is normal temperature need to be pressed twice in order to obtain a predetermined thickness, which is not desirable from the viewpoint of suppressing the manufacturing cost. On the other hand, the positive plates of Examples 1, 3, 5, 7, and 9 in which the press temperature is 70 ° C. and the positive plates of Examples 2, 4, 6, 8, and 10 in which the press temperature is 100 ° C. Can be done once. This is considered to be because PVDF contained in the positive electrode mixture is softened and the workability is increased by pressing the positive electrode plate while heating. The pressing temperature is preferably 70 ° C or higher. When the press temperature was lower than 70 ° C., it was almost the same as that at room temperature.

また、正極合剤の剥離が生じておらず、プレス温度が110℃である比較例12、13、18、19、24では、プレス加工性は良好であるが、正極板が硬くなり過ぎたため、正極板4及び負極板3を巻回して電極エレメント2を作成する際に、正極板4に切断又は亀裂が生じた。正極板(正極合剤)の硬化の原因としては、高温で加熱したことによって軟化したPVDFが、AB又は正極活物質の隙間に広がり、これらを強固に接着したためであると考えられる。よって、正極板4のプレス加工性及び柔軟性を共に良好なものとするためには、プレス温度を100℃以下とする必要がある。   Further, in Comparative Examples 12, 13, 18, 19, and 24 where the positive electrode mixture was not peeled off and the press temperature was 110 ° C., the press workability was good, but the positive electrode plate was too hard, When forming the electrode element 2 by winding the positive electrode plate 4 and the negative electrode plate 3, the positive electrode plate 4 was cut or cracked. The cause of the curing of the positive electrode plate (positive electrode mixture) is considered to be that PVDF softened by heating at a high temperature spreads in the gaps of AB or the positive electrode active material and bonds them firmly. Therefore, in order to improve both the press workability and flexibility of the positive electrode plate 4, it is necessary to set the press temperature to 100 ° C. or less.

本発明において、正極の導電剤に用いるカーボンブラックは、炭化水素を不完全燃焼あるいは熱分解することによって得られる炭素のコロイド状の微粉末である。使用する炭化水素原料の種別や製造方法の違いにより、様々な種類のカーボンブラックがあり、例えばアセチレンを熱分解して得られるアセチレンブラックなどがあるが、他に、原料や製造方法および用途などの違いにより、ケッチェンブラック、ガスブラック、オイルブラック、ナフタリンブラック、サーマルブラック、ファーネスブラック、ランプブラック、チャンネルブラック、ロールブラック、ディスクブラック、電池用ブラック、導電性ブラック、ゴム用ブラック、カラー用ブラックなどがある。   In the present invention, carbon black used as the conductive agent for the positive electrode is a colloidal fine powder of carbon obtained by incomplete combustion or thermal decomposition of hydrocarbons. There are various types of carbon black depending on the type of hydrocarbon raw material used and the manufacturing method, for example, acetylene black obtained by pyrolyzing acetylene, but there are other raw materials, manufacturing methods and uses, etc. Depending on the difference, ketjen black, gas black, oil black, naphthalene black, thermal black, furnace black, lamp black, channel black, roll black, disc black, battery black, conductive black, rubber black, color black, etc. There is.

また、上述した実施例では、正極の導電剤に用いるカーボンブラックとして、BET比表面積が約70m2 /gである電気化学工業社製の粒状アセチレンブラックを用いたが、これ以外のグレードのアセチレンブラック、あるいはアセチレンブラック以外のファーネスブラックなどのカーボンブラックを用いることも可能である。これらのBET比表面積は正極活物質のBET比表面積とくらべて十分に大きく、また、これらの粉体特性が似ており、本実施例と同様の性状を示す。本発明においてカーボンブラックの種別は限定されないが、アセチレンブラックは導電性が高いことから、特に好ましい。 In the above-mentioned examples, granular acetylene black manufactured by Denki Kagaku Kogyo Co., Ltd. having a BET specific surface area of about 70 m 2 / g was used as carbon black used for the conductive agent of the positive electrode. However, acetylene black of other grades was used. Alternatively, carbon black such as furnace black other than acetylene black can be used. These BET specific surface areas are sufficiently larger than the BET specific surface area of the positive electrode active material, and these powder characteristics are similar to each other, showing the same properties as in this example. In the present invention, the type of carbon black is not limited, but acetylene black is particularly preferable because of its high conductivity.

また、正極活物質の原料は、上述した実施例に限るものではなく、炭酸リチウム、水酸化リチウム、硝酸リチウム等に代表されるリチウム化合物と、酸化コバルト、水酸化コバルト、炭酸コバルト、硝酸コバルト塩等に代表されるコバルト化合物を用いてもよい。また、正極活物質中の微量元素として、例えば、マグネシウム(Mg)、アルミニウム(Al)、カルシウム(Ca)、マンガン(Mn)、鉄(Fe)、ニッケル(Ni)、亜鉛(Zn)、ジルコニウム(Zr)、ストロンチウム(Sr)、ナトリウム(Na)、フッ素(F)、硫黄(S)などの元素、および、微量の酸化物、水酸化物、塩などを含んでもよい。また、活物質粒子のBET比表面積および粒度分布は、リチウム原料やコバルト原料の粒子形状等の制御や、リチウム原料とコバルト原料との混合比の調整、混合原料の造粒、あるいはコバルト酸リチウムの焼成条件、他元素添加などによって制御してもよい。また、コバルト酸リチウムでなくとも、ニッケル、マンガンなどの他の遷移金属化合物の単独、あるいは、これらの複合酸化物であってもよい。   The raw material of the positive electrode active material is not limited to the above-described examples, and lithium compounds represented by lithium carbonate, lithium hydroxide, lithium nitrate, and the like, and cobalt oxide, cobalt hydroxide, cobalt carbonate, cobalt nitrate salt Cobalt compounds represented by the above may be used. Further, as trace elements in the positive electrode active material, for example, magnesium (Mg), aluminum (Al), calcium (Ca), manganese (Mn), iron (Fe), nickel (Ni), zinc (Zn), zirconium ( Zr), strontium (Sr), sodium (Na), fluorine (F), sulfur (S), and other elements, and trace amounts of oxides, hydroxides, salts, and the like may be included. Further, the BET specific surface area and particle size distribution of the active material particles are controlled by controlling the particle shape of the lithium raw material and the cobalt raw material, adjusting the mixing ratio of the lithium raw material and the cobalt raw material, granulation of the mixed raw material, or lithium cobalt oxide You may control by baking conditions, addition of other elements, etc. In addition, lithium cobaltate may be used alone or in combination with other transition metal compounds such as nickel and manganese.

本発明に係る非水電解質二次電池の概略構成を示す断面図である。It is sectional drawing which shows schematic structure of the nonaqueous electrolyte secondary battery which concerns on this invention.

符号の説明Explanation of symbols

1 電池
2 電極エレメント
3 負極板
4 正極板
5 セパレータ
6 電池ケース
7 電池蓋
8 安全弁
9 負極端子
10 負極リード
DESCRIPTION OF SYMBOLS 1 Battery 2 Electrode element 3 Negative electrode plate 4 Positive electrode plate 5 Separator 6 Battery case 7 Battery cover 8 Safety valve 9 Negative electrode terminal 10 Negative electrode lead

Claims (3)

カーボンブラック及びポリフッ化ビニリデンを含有する正極合剤を有し、100℃以下でプレスされた正極を備える非水電解質二次電池において、
前記正極合剤に対する前記カーボンブラックの割合が1質量%以上3質量%以下であり、
前記正極合剤に対する前記ポリフッ化ビニリデンの割合が2質量%以上4質量%以下であり、
前記ポリフッ化ビニリデンに対する前記カーボンブラックの質量比が0.33以上0.75以下であることを特徴とする非水電解質二次電池。
In a non-aqueous electrolyte secondary battery having a positive electrode mixture containing carbon black and polyvinylidene fluoride and having a positive electrode pressed at 100 ° C. or lower,
The ratio of the carbon black to the positive electrode mixture is 1% by mass or more and 3% by mass or less,
The ratio of the polyvinylidene fluoride to the positive electrode mixture is 2% by mass or more and 4% by mass or less,
A nonaqueous electrolyte secondary battery, wherein a mass ratio of the carbon black to the polyvinylidene fluoride is 0.33 or more and 0.75 or less.
カーボンブラック及びポリフッ化ビニリデンを含有する正極合剤を有し、70℃以上100℃以下でプレスされた正極を備える非水電解質二次電池において、
前記正極合剤に対する前記カーボンブラックの割合が1質量%以上3質量%以下であり、
前記正極合剤に対する前記ポリフッ化ビニリデンの割合が2質量%以上4質量%以下であり、
前記ポリフッ化ビニリデンに対する前記カーボンブラックの質量比が0.33以上0.75以下であることを特徴とする非水電解質二次電池。
In a non-aqueous electrolyte secondary battery having a positive electrode mixture containing carbon black and polyvinylidene fluoride and comprising a positive electrode pressed at 70 ° C. or higher and 100 ° C. or lower,
The ratio of the carbon black to the positive electrode mixture is 1% by mass or more and 3% by mass or less,
The ratio of the polyvinylidene fluoride to the positive electrode mixture is 2% by mass or more and 4% by mass or less,
A nonaqueous electrolyte secondary battery, wherein a mass ratio of the carbon black to the polyvinylidene fluoride is 0.33 or more and 0.75 or less.
前記カーボンブラックは、アセチレンブラックを含むことを特徴とする請求項1又は2記載の非水電解質二次電池。   The non-aqueous electrolyte secondary battery according to claim 1, wherein the carbon black contains acetylene black.
JP2005155982A 2005-05-27 2005-05-27 Nonaqueous electrolyte secondary battery Pending JP2006331937A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022145473A (en) * 2021-03-19 2022-10-04 積水化学工業株式会社 Cathode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery using the same, battery module, and battery system
US20230178723A1 (en) * 2021-03-19 2023-06-08 Sekisui Chemical Co., Ltd. Positive electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery, battery module and battery system using the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001110456A (en) * 1999-10-14 2001-04-20 Ngk Insulators Ltd Lithium secondary battery and manufacturing method for wound-type electrode body
JP2003157831A (en) * 2001-11-21 2003-05-30 Mitsubishi Cable Ind Ltd Positive electrode plate for lithium ion secondary battery, its manufacturing method and lithium secondary battery using it

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001110456A (en) * 1999-10-14 2001-04-20 Ngk Insulators Ltd Lithium secondary battery and manufacturing method for wound-type electrode body
JP2003157831A (en) * 2001-11-21 2003-05-30 Mitsubishi Cable Ind Ltd Positive electrode plate for lithium ion secondary battery, its manufacturing method and lithium secondary battery using it

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022145473A (en) * 2021-03-19 2022-10-04 積水化学工業株式会社 Cathode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery using the same, battery module, and battery system
JP7197670B2 (en) 2021-03-19 2022-12-27 積水化学工業株式会社 Positive electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery, battery module, and battery system using the same
US20230178723A1 (en) * 2021-03-19 2023-06-08 Sekisui Chemical Co., Ltd. Positive electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery, battery module and battery system using the same

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