JP2006032296A - Negative electrode and nonaqueous electrolyte secondary battery - Google Patents
Negative electrode and nonaqueous electrolyte secondary battery Download PDFInfo
- Publication number
- JP2006032296A JP2006032296A JP2004213526A JP2004213526A JP2006032296A JP 2006032296 A JP2006032296 A JP 2006032296A JP 2004213526 A JP2004213526 A JP 2004213526A JP 2004213526 A JP2004213526 A JP 2004213526A JP 2006032296 A JP2006032296 A JP 2006032296A
- Authority
- JP
- Japan
- Prior art keywords
- negative electrode
- secondary battery
- battery
- mass
- electrolyte secondary
- 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
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
Landscapes
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は、リチウム二次電池などの非水電解質二次電池に用いる負極、及び、該負極を備える非水電解質二次電池に関する。 The present invention relates to a negative electrode used for a nonaqueous electrolyte secondary battery such as a lithium secondary battery, and a nonaqueous electrolyte secondary battery including the negative electrode.
近年、携帯機器などの電子機器の高性能化に伴い、前記電子機器に内蔵する二次電池の性能向上に対する要求が高まっている。その中でも、電池容量とサイクル寿命特性との向上に対する要求が高まっている。代表的な二次電池としてリチウム二次電池があるが、リチウム二次電池においても高容量化が求められており、規定サイズ内でできるだけ大きな容量を得るために、正極及び負極をプレスにより圧縮するなどして活物質を可能な限り詰込んでいる。リチウム二次電池は、一般に、活物質粒子と結着剤（バインダ）とを圧縮して極板を成形しているが、前記圧縮を行うことにより、極板中の空隙が減少して電解液の浸透性が悪くなり、サイクル寿命特性が低下する傾向にある。特に、炭素材料を主成分とする負極に関しては、サイクル寿命特性の低下が顕著に表れる。 In recent years, with the improvement in performance of electronic devices such as portable devices, there is an increasing demand for improving the performance of secondary batteries built in the electronic devices. Among them, there is an increasing demand for improvement of battery capacity and cycle life characteristics. As a typical secondary battery, there is a lithium secondary battery. However, a lithium secondary battery is also required to have a high capacity, and in order to obtain as large a capacity as possible within a specified size, the positive electrode and the negative electrode are compressed by a press. The active material is packed as much as possible. In general, a lithium secondary battery compresses active material particles and a binder (binder) to form an electrode plate. However, by performing the compression, a void in the electrode plate is reduced and an electrolyte solution is formed. , The cycle life characteristics tend to deteriorate. In particular, for a negative electrode mainly composed of a carbon material, the cycle life characteristics are significantly reduced.
なお、リチウム二次電池の負極への電解液の浸透性を向上させる手法として、負極を構成する結着剤の量を少なくする手法が知られている。負極の結着剤にはカルボキシメチルセルロースとスチレンブタジエンゴム（ＳＢＲ）とが用いられる場合が多いが、カルボキシメチルセルロースは、結着性を付与する作用の他に、ペーストを安定させる増粘剤としての役割も果たしている。そのため、カルボキシメチルセルロースの量を少なくした場合、増粘効果が減少し、ペーストの安定性が著しく低下するため、生産性に支障をきたすという問題が生じる。 As a technique for improving the permeability of the electrolyte solution to the negative electrode of the lithium secondary battery, a technique for reducing the amount of the binder constituting the negative electrode is known. Carboxymethylcellulose and styrene butadiene rubber (SBR) are often used as the binder for the negative electrode, but carboxymethylcellulose plays a role as a thickening agent that stabilizes the paste in addition to the action of imparting binding properties. Also plays. Therefore, when the amount of carboxymethylcellulose is reduced, the thickening effect is reduced, and the stability of the paste is remarkably lowered, resulting in a problem that the productivity is hindered.
このような問題を解決する方法として、カルボキシメチルセルロースよりも少ない添加量で、ペーストの安定性を良好に保つことができるポリアクリル酸を負極の結着剤に用いたリチウム二次電池が提案されている（例えば、特許文献１参照）。ポリアクリル酸を用いることにより、例えば充填密度が１．５ｇ／ｃｃ以上の高密度負極においても、生産性を損ねることなく負極への電解液の浸透性を保つことができ、高率放電特性、サイクル特性などの電池性能の向上を図ることができる。
ポリアクリル酸リチウムを負極の結着剤として用いる際に、ポリアクリル酸リチウムの特徴である負極板への電解液の浸透性の良さを生かすためには、その添加量を炭素材料に対して、０．０５％〜０．５％などの少ない量にする必要がある。しかし、ポリアクリル酸リチウムの量を少なくした場合、活物質と集電体とをつなぐ結着剤の量が減少するため、繰返しの充放電に伴う負極活物質の膨張収縮作用により、活物質と集電体との間の導電経路が断裂され、サイクル寿命特性の低下が起こる。このように、ポリアクリル酸リチウムの添加量を少なくした場合、負極への電解液の浸透性が良くなって高率放電特性、サイクル特性は改善するが、サイクルの進行に伴いポリアクリル酸の結着力が弱くなり、良好なサイクル寿命特性を維持することができなくなるという問題がある。 When using lithium polyacrylate as a binder for the negative electrode, in order to take advantage of the good permeability of the electrolyte to the negative electrode plate, which is a feature of lithium polyacrylate, the amount of addition to the carbon material, It is necessary to make the amount as small as 0.05% to 0.5%. However, when the amount of lithium polyacrylate is reduced, the amount of the binder that connects the active material and the current collector decreases, so that the active material and the active material The conductive path between the current collector and the current collector is broken, and the cycle life characteristics are deteriorated. As described above, when the amount of lithium polyacrylate added is reduced, the permeability of the electrolyte to the negative electrode is improved and the high rate discharge characteristics and cycle characteristics are improved. There is a problem that the adhering force becomes weak and it becomes impossible to maintain good cycle life characteristics.
本発明は斯かる事情に鑑みてなされたものであり、ポリアクリル酸と、気相成長炭素繊維又はカーボンブラックと、他の炭素材料とを含んだ負極を用いることにより、高密度負極への電解液の良好な浸透性が得られることに加え、サイクル寿命特性を向上させることができる負極及び非水電解質二次電池を提供することを目的とする。 The present invention has been made in view of such circumstances, and by using a negative electrode containing polyacrylic acid, vapor-grown carbon fiber or carbon black, and another carbon material, electrolysis to a high-density negative electrode is achieved. An object of the present invention is to provide a negative electrode and a non-aqueous electrolyte secondary battery that can improve cycle life characteristics in addition to obtaining good liquid permeability.
第１発明に係る負極は、非水電解質二次電池に用いる負極において、ポリアクリル酸と、気相成長炭素繊維又はカーボンブラックと、気相成長炭素繊維又はカーボンブラック以外の炭素材料とを含むことを特徴とする。 The negative electrode according to the first invention is a negative electrode used for a nonaqueous electrolyte secondary battery, and includes polyacrylic acid, vapor-grown carbon fiber or carbon black, and a carbon material other than vapor-grown carbon fiber or carbon black. It is characterized by.
第２発明に係る非水電解質二次電池は、第１発明の負極を備えることを特徴とする。 A nonaqueous electrolyte secondary battery according to a second aspect of the invention includes the negative electrode of the first aspect of the invention.
本発明において、負極は、ポリアクリル酸と、気相成長炭素繊維又はカーボンブラックと、他の炭素材料とを含む。一般的な黒鉛系の導電助剤である鱗片状黒鉛は、極板をプレスした場合に配向してしまい、粒子間をつなぐ導電経路が不十分になる。一方、気相成長炭素繊維又はカーボンブラックは、このような配向は起こらないため、極板をプレスした場合であっても十分な導電経路を確保できる。ポリアクリル酸リチウムなどのポリアクリル酸を用いることにより、高率放電特性、サイクル特性を改善できることに加え、気相成長炭素繊維又はカーボンブラックを用いることにより、導電性を向上させて、サイクル寿命特性を向上できる。 In the present invention, the negative electrode includes polyacrylic acid, vapor-grown carbon fiber or carbon black, and another carbon material. Scale-like graphite, which is a general graphite-based conductive additive, is oriented when the electrode plate is pressed, and the conductive path that connects the particles becomes insufficient. On the other hand, since the vapor-grown carbon fiber or carbon black does not cause such orientation, a sufficient conductive path can be secured even when the electrode plate is pressed. By using polyacrylic acid such as lithium polyacrylate, the high rate discharge characteristics and cycle characteristics can be improved, and by using vapor-grown carbon fiber or carbon black, conductivity is improved and cycle life characteristics are improved. Can be improved.
本発明によれば、高密度負極への電解液の良好な浸透性が得られることに加え、サイクル寿命特性を向上させることができる。 According to the present invention, it is possible to improve cycle life characteristics in addition to obtaining good permeability of the electrolytic solution to the high-density negative electrode.
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。
（実施例１）
図１は、本発明に係るリチウム二次電池（非水電解質二次電池）の一例を示す断面図である。図１において、１はリチウム二次電池（以下、電池という）、２は電極群、３は負極、４は正極、５はセパレータ、６は電池ケース、７は電池蓋、８は安全弁、９は負極端子、１０は負極リードである。電極群２は、負極３と正極４とをセパレータ５を介して巻回したものである。電極群２は電池ケース６に収納してあり、電池ケース６の開口部は、負極端子９及び安全弁８を備える電池蓋７をレーザー溶接することにより密封されている。負極端子９は負極リード１０と接続され、正極４は電池ケース６と接続されている。
Hereinafter, the present invention will be specifically described with reference to the drawings illustrating embodiments thereof.
Example 1
FIG. 1 is a cross-sectional view showing an example of a lithium secondary battery (nonaqueous electrolyte secondary battery) according to the present invention. In FIG. 1, 1 is a lithium secondary battery (hereinafter referred to as a battery), 2 is an electrode group, 3 is a negative electrode, 4 is a positive electrode, 5 is a separator, 6 is a battery case, 7 is a battery lid, 8 is a safety valve, and 9 is The
正極合剤は、活物質としてＬｉＣｏＯ2 ９０質量％と、導電助剤としてアセチレンブラック５質量％と、結着剤としてポリフッ化ビニリデン（ＰＶＤＦ）５質量％とを混合し、Ｎ−メチル−２−ピロリドン（ＮＰＭ）に分散させることによりペーストを調製した。このペーストを厚さ２０μｍのアルミニウム集電体に均一に塗布して、乾燥させた後、ロールプレスで圧縮成形することにより正極を作製した。 The positive electrode mixture was prepared by mixing 90% by mass of LiCoO 2 as an active material, 5% by mass of acetylene black as a conductive additive, and 5% by mass of polyvinylidene fluoride (PVDF) as a binder, and N-methyl-2- A paste was prepared by dispersing in pyrrolidone (NPM). This paste was uniformly applied to an aluminum current collector with a thickness of 20 μm, dried, and then compression molded with a roll press to produce a positive electrode.
負極合剤は、負極活物質として炭素材料９５．３質量％と、気相成長炭素繊維（ＶＧＣＦ）２質量％と、結着剤としてスチレンブタジエンゴム（ＳＢＲ）２質量％と、カルボキシメチルセルロース（ＣＭＣ）０．４質量％と、ポリアクリル酸リチウム０．３質量％とを混合し、水を適宜加えて分散させ、ペーストを調製した。このペーストを厚さ１５μｍの銅集電体に均一に塗布し、乾燥させて水を蒸発させた後、ロールプレスで圧縮成形することにより負極を作製した。 The negative electrode mixture comprises 95.3% by mass of a carbon material as a negative electrode active material, 2% by mass of vapor grown carbon fiber (VGCF), 2% by mass of styrene butadiene rubber (SBR) as a binder, and carboxymethyl cellulose (CMC). ) 0.4% by mass and 0.3% by mass of lithium polyacrylate were mixed, and water was appropriately added and dispersed to prepare a paste. This paste was uniformly applied to a 15 μm thick copper current collector, dried to evaporate water, and then subjected to compression molding with a roll press to produce a negative electrode.
セパレータとしては、厚さ２０μｍ程度の微多孔性ポリエチレンフィルムを用いた。電解質としては、エチレンカーボネート（ＥＣ）及びエチルメチルカーボネート（ＥＭＣ）の体積比３：７混合溶媒にＬｉＰＦ6 を１．１ｍｏｌ／ｌ溶解させたものを用いた。電池のサイズは横幅３０ｍｍ、高さ４０ｍｍ、厚さ５ｍｍであり、容量は７２０ｍＡｈである。 As the separator, a microporous polyethylene film having a thickness of about 20 μm was used. As the electrolyte, a solution obtained by dissolving 1.1 mol / l of LiPF 6 in a 3: 7 mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) was used. The battery has a width of 30 mm, a height of 40 mm, a thickness of 5 mm, and a capacity of 720 mAh.
（実施例２）
負極合剤は、負極活物質として炭素材料９５．３質量％と、カーボンブラック２質量％と、結着剤としてスチレンブタジエンゴム（ＳＢＲ）２質量％と、カルボキシメチルセルロース（ＣＭＣ）０．４質量％と、ポリアクリル酸リチウム０．３質量％とを混合し、水を適宜加えて分散させ、ペーストを調製した。他は実施例１と同様にして電池を作製した。
(Example 2)
The negative electrode mixture is composed of 95.3% by mass of a carbon material as a negative electrode active material, 2% by mass of carbon black, 2% by mass of styrene butadiene rubber (SBR) as a binder, and 0.4% by mass of carboxymethyl cellulose (CMC). And 0.3% by mass of lithium polyacrylate were mixed, and water was appropriately added and dispersed to prepare a paste. A battery was fabricated in the same manner as in Example 1 except for the above.
（比較例１）
負極合剤は、負極活物質として炭素材料（ただし、ＶＧＣＦ、カーボンブラックは含んでいない）９５．３質量％と、鱗片状黒鉛２質量％と、結着剤としてスチレンブタジエンゴム（ＳＢＲ）２質量％と、カルボキシメチルセルロース（ＣＭＣ）０．４質量％と、ポリアクリル酸リチウム０．３質量％とを混合し、水を適宜加えて分散させ、ペーストを調製した。他は実施例１と同様にして電池を作製した。
(Comparative Example 1)
The negative electrode mixture is 95.3% by mass of a carbon material (but not including VGCF and carbon black) as a negative electrode active material, 2% by mass of flaky graphite, and 2% by mass of styrene butadiene rubber (SBR) as a binder. %, Carboxymethyl cellulose (CMC) 0.4 mass%, and lithium polyacrylate 0.3 mass% were mixed, and water was added as appropriate to disperse to prepare a paste. A battery was fabricated in the same manner as in Example 1 except for the above.
（比較例２）
負極合剤は、負極活物質として炭素材料（ただし、ＶＧＣＦ、カーボンブラックは含んでいない）９５質量％と、鱗片状黒鉛２質量％と、結着剤としてスチレンブタジエンゴム（ＳＢＲ）２質量％と、カルボキシメチルセルロース（ＣＭＣ）１質量％とを混合し、水を適宜加えて分散させ、ペーストを調製した。他は実施例１と同様にして電池を作製した。
(Comparative Example 2)
The negative electrode mixture comprises 95% by mass of a carbon material (but not including VGCF and carbon black) as a negative electrode active material, 2% by mass of flaky graphite, and 2% by mass of styrene butadiene rubber (SBR) as a binder. Then, 1% by mass of carboxymethylcellulose (CMC) was mixed, and water was appropriately added and dispersed to prepare a paste. A battery was fabricated in the same manner as in Example 1 except for the above.
各実施例及び各比較例の電池の負極に対して、電解液の浸透時間を測定した。浸透時間は、所定量の電解液を負極上に滴下し、滴下した電解液が負極に完全に染み込むまでの時間を測定した。測定は、各実施例及び各比較例の電池を１０セルずつ用意し、１０セルの平均を求めた。測定結果を表１に示す。ただし、表１においては、比較例２の時間を基準にした比率（％）を示している。よって、比率（％）が小さい方が電解液の浸透性に優れる。 The permeation time of the electrolyte was measured with respect to the negative electrode of the battery of each example and each comparative example. The permeation time was measured by dropping a predetermined amount of the electrolyte on the negative electrode and measuring the time until the dropped electrolyte completely penetrates the negative electrode. For the measurement, 10 cells of each example and each comparative example were prepared, and the average of 10 cells was obtained. The measurement results are shown in Table 1. However, in Table 1, the ratio (%) based on the time of Comparative Example 2 is shown. Therefore, the smaller the ratio (%), the better the electrolyte permeability.
表１の実施例１，２、比較例１に示すように、負極結着剤にポリアクリル酸リチウムを含む場合、負極活物質の種類に関係無く、電解液の浸透性は良好である。なお、比較例２のＣＭＣの量を実施例１、２、又は比較例１と同程度まで少なくすることにより、電解液の浸透性は向上すると考えられるが、ＣＭＣによる増粘効果が低減するため、現実的ではない。 As shown in Examples 1 and 2 and Comparative Example 1 in Table 1, when the negative electrode binder contains lithium polyacrylate, the permeability of the electrolytic solution is good regardless of the type of the negative electrode active material. In addition, although it is thought that the permeability of electrolyte solution improves by reducing the quantity of CMC of the comparative example 2 to Example 1 and 2 or the comparative example 1, it is because the thickening effect by CMC reduces. Is not realistic.
次に、各実施例及び各比較例の電池の高率放電特性、低温放電特性、パルス放電特性、及びサイクル寿命特性を測定した。高率放電特性は、２５℃の環境下において１ＣｍＡ（＝７２０ｍＡ）の一定電流で４．２Ｖまで充電後、４．２Ｖの一定電圧で３時間充電する。その後、２５℃の環境下において２ＣｍＡ（＝１４４０ｍＡ）の一定電流で２．７５Ｖまで放電し、放電容量を測定する。低温放電特性は、２５℃の環境下において１ＣｍＡの一定電流で４．２Ｖまで充電後、４．２Ｖの一定電圧で３時間充電する。その後、０℃の環境下において１ＣｍＡの一定電流で２．７５Ｖまで放電し、放電容量を測定する。パルス放電特性は、２５℃の環境下において１ＣｍＡの一定電流で４．２Ｖまで充電後、４．２Ｖの一定電圧で３時間充電する。その後、０℃の環境下において７４１ｍＡ×６．６ｍｓ＋６５ｍＡ×１３．４ｍｓの矩形波パルス電流で２．７５Ｖまで放電し、放電容量を測定する。測定は、各実施例及び各比較例の電池を１０セルずつ用意し、１０セルの平均を求めた。測定結果を表２に示す。ただし、表２においては、比較例２の測定値を基準にした比率（％）を示している。よって、比率（％）が大きい方が優れた特性である。 Next, the high rate discharge characteristics, the low temperature discharge characteristics, the pulse discharge characteristics, and the cycle life characteristics of the batteries of each Example and each Comparative Example were measured. The high-rate discharge characteristic is that the battery is charged to 4.2 V with a constant current of 1 CmA (= 720 mA) in an environment of 25 ° C. and then charged with a constant voltage of 4.2 V for 3 hours. Thereafter, the battery is discharged to 2.75 V at a constant current of 2 CmA (= 1440 mA) in an environment of 25 ° C., and the discharge capacity is measured. The low-temperature discharge characteristic is that the battery is charged to 4.2 V with a constant current of 1 CmA in an environment of 25 ° C. and then charged with a constant voltage of 4.2 V for 3 hours. Thereafter, the battery is discharged to 2.75 V with a constant current of 1 CmA in an environment of 0 ° C., and the discharge capacity is measured. In the pulse discharge characteristic, the battery is charged to 4.2 V with a constant current of 1 CmA in an environment of 25 ° C., and then charged with a constant voltage of 4.2 V for 3 hours. Thereafter, the battery is discharged to 2.75 V with a square wave pulse current of 741 mA × 6.6 ms + 65 mA × 13.4 ms in an environment of 0 ° C., and the discharge capacity is measured. For the measurement, 10 cells of each example and each comparative example were prepared, and the average of 10 cells was obtained. The measurement results are shown in Table 2. However, in Table 2, the ratio (%) based on the measured value of Comparative Example 2 is shown. Therefore, a larger ratio (%) is a superior characteristic.
また、サイクル寿命特性は、２５℃の環境下において１ＣｍＡの一定電流で４．２Ｖまで充電後、４．２Ｖの一定電圧で３時間充電する。その後、２５℃の環境下において１ＣｍＡの一定電流で２．７５Ｖまで放電し、放電容量を測定する。これら充電及び放電を５００回繰返す。測定は、各実施例及び各比較例の電池を１０セルずつ用意し、１０セルの平均を求めた。測定結果を図２及び表２に示す。ただし、表２においては、充電及び放電を５００回繰返した場合の比較例２の測定値を基準にした比率（％）を示している。よって、比率（％）が大きい方が優れた特性である。 The cycle life characteristic is that the battery is charged to 4.2 V at a constant current of 1 CmA in an environment of 25 ° C. and then charged at a constant voltage of 4.2 V for 3 hours. Thereafter, the battery is discharged to 2.75 V at a constant current of 1 CmA in an environment of 25 ° C., and the discharge capacity is measured. These charging and discharging are repeated 500 times. For the measurement, 10 cells of each example and each comparative example were prepared, and the average of 10 cells was obtained. The measurement results are shown in FIG. However, in Table 2, the ratio (%) based on the measured value of Comparative Example 2 when charging and discharging are repeated 500 times is shown. Therefore, a larger ratio (%) is a superior characteristic.
表２の実施例１，２、比較例１に示すように、負極結着剤にポリアクリル酸リチウムを含む場合、高率放電特性、低温放電特性、及びパルス放電特性は、負極活物質の種類に関係無く、良好である。これは、表１に示したように、負極への電解液の浸透性が良好であり、リチウムイオンが円滑に移動できるためであると考えられる。 As shown in Examples 1 and 2 and Comparative Example 1 of Table 2, when the negative electrode binder contains lithium polyacrylate, the high rate discharge characteristics, the low temperature discharge characteristics, and the pulse discharge characteristics are the types of the negative electrode active material. Regardless of, it is good. This is considered to be because, as shown in Table 1, the electrolyte has good permeability to the negative electrode, and lithium ions can move smoothly.
ここで、比較例１は、負極結着剤にポリアクリル酸リチウムを含むため、負極への電解液の浸透性が良好であり、サイクル序盤の容量低下が抑えられる。そのため、図２に示すように、サイクル序盤の特性は良好である。しかし、充放電の繰返しに伴って負極粒子間の導電性が不完全になっていくため、表２及び図２に示すように、サイクル終盤の特性は大きく劣化している。 Here, since Comparative Example 1 includes lithium polyacrylate in the negative electrode binder, the permeability of the electrolytic solution into the negative electrode is good, and the capacity reduction at the beginning of the cycle is suppressed. Therefore, as shown in FIG. 2, the characteristics at the beginning of the cycle are good. However, since the conductivity between the negative electrode particles becomes incomplete as charging and discharging are repeated, the characteristics at the end of the cycle are greatly degraded as shown in Table 2 and FIG.
また、実施例１，２は、負極結着剤にポリアクリル酸リチウムを含むため、比較例１と同様に、負極への電解液の浸透性が良好であり、サイクル序盤の容量低下が抑えられる。そのため、図２に示すように、サイクル序盤の特性は良好である。一方、負極活物質に比較例１とは異なるＶＧＣＦ又はカーボンブラックを用いた実施例１，２は、表２及び図２に示すように、サイクル終盤の特性は良好である。 Moreover, since Examples 1 and 2 contain lithium polyacrylate in the negative electrode binder, the permeability of the electrolyte solution to the negative electrode is good as in Comparative Example 1, and the capacity reduction at the beginning of the cycle is suppressed. . Therefore, as shown in FIG. 2, the characteristics at the beginning of the cycle are good. On the other hand, Examples 1 and 2 using VGCF or carbon black different from Comparative Example 1 as the negative electrode active material have good cycle end characteristics as shown in Table 2 and FIG.
このように、負極結着剤にポリアクリル酸（ポリアクリル酸リチウム）を含むことに加え、負極活物質にＶＧＣＦ又はカーボンブラックを含むことにより、効率放電特性、低温放電特性、及びパルス放電特性を向上できることに加え、サイクル寿命特性の低下を抑制することができる。 As described above, in addition to including polyacrylic acid (lithium polyacrylate) in the negative electrode binder, VGCF or carbon black is included in the negative electrode active material, thereby improving efficiency discharge characteristics, low temperature discharge characteristics, and pulse discharge characteristics. In addition to the improvement, it is possible to suppress a decrease in cycle life characteristics.
ここで、負極合剤は上述した実施の形態に限定はされず、炭素材料（ＶＧＣＦ、カーボンブラックは含まない）９４．８〜９８．１質量％と、ＶＧＣＦ又はカーボンブラック０．５〜２．５質量％と、ポリアクリル酸リチウム０．２〜０．６質量％と、ＣＭＣ０．２〜０．６質量％と、ＳＢＲ１．０〜１．５質量％と、適量の水とを混合して負極合剤のペーストを調整することが可能である。また、炭素材料（ＶＧＣＦ、カーボンブラックは含まない）と、ＶＧＣＦ又はカーボンブラック、及びポリアクリル酸リチウムとの最適な比率は、炭素材料が９５〜９９質量％、ＶＧＣＦ又はカーボンブラック、及びポリアクリル酸リチウムが１〜５質量％である。ＶＧＣＦ及びカーボンブラックは、鱗片状黒鉛と比べて少量の添加であっても優れた導電性が得られる。また、ポリアクリル酸リチウムは、ＣＭＣと比べて少量の添加であっても増粘効果が得られる。 Here, the negative electrode mixture is not limited to the above-described embodiment, and 94.8 to 98.1% by mass of a carbon material (not including VGCF and carbon black) and VGCF or carbon black 0.5 to 2. 5% by mass, lithium polyacrylate 0.2-0.6% by mass, CMC 0.2-0.6% by mass, SBR 1.0-1.5% by mass, and an appropriate amount of water It is possible to adjust the paste of the negative electrode mixture. The optimal ratio of carbon material (VGCF, carbon black not included), VGCF or carbon black, and lithium polyacrylate is 95 to 99% by mass of carbon material, VGCF or carbon black, and polyacrylic acid. Lithium is 1 to 5% by mass. VGCF and carbon black have excellent conductivity even when added in a small amount as compared with flaky graphite. In addition, lithium polyacrylate can provide a thickening effect even when added in a small amount as compared with CMC.
上述した実施の形態においては、ポリアクリル酸（ポリアクリル酸リチウム）を例にして説明したが、ポリアクリル酸に代えて、ポリメタアクリル酸を用いることも可能である。また、ビニレンカーボネート、グリコールサルフェート、プロピレングリコールサルフェート、ホスファゼン、およびジビニルカーボネートの何れかが添加された電解液を用いることにより、サイクル寿命特性をさらに向上させることも可能である。 In the above-described embodiment, polyacrylic acid (polylithium acrylate) has been described as an example. However, polymethacrylic acid can be used instead of polyacrylic acid. In addition, cycle life characteristics can be further improved by using an electrolytic solution to which any of vinylene carbonate, glycol sulfate, propylene glycol sulfate, phosphazene, and divinyl carbonate is added.
１ 電池（非水電解質二次電池）
２ 電極群
３ 負極
４ 正極
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
1 battery (non-aqueous electrolyte secondary battery)
2
Claims (2)
ポリアクリル酸と、
気相成長炭素繊維又はカーボンブラックと、
気相成長炭素繊維又はカーボンブラック以外の炭素材料と
を含むことを特徴とする負極。 In the negative electrode used for the nonaqueous electrolyte secondary battery,
With polyacrylic acid,
Vapor grown carbon fiber or carbon black;
And a carbon material other than vapor-grown carbon fiber or carbon black.
A non-aqueous electrolyte secondary battery comprising the negative electrode according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004213526A JP2006032296A (en) | 2004-07-21 | 2004-07-21 | Negative electrode and nonaqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004213526A JP2006032296A (en) | 2004-07-21 | 2004-07-21 | Negative electrode and nonaqueous electrolyte secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2006032296A true JP2006032296A (en) | 2006-02-02 |
Family
ID=35898357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2004213526A Pending JP2006032296A (en) | 2004-07-21 | 2004-07-21 | Negative electrode and nonaqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2006032296A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007287570A (en) * | 2006-04-19 | 2007-11-01 | Iwate Univ | Lithium ion secondary battery |
| JP2009135103A (en) * | 2007-11-28 | 2009-06-18 | Samsung Sdi Co Ltd | Negative electrode for lithium secondary battery, and lithium secondary battery containing this |
| EP2122723A1 (en) * | 2007-02-06 | 2009-11-25 | 3M Innovative Properties Company | Electrodes including novel binders and methods of making and using the same |
| JP2010519706A (en) * | 2007-02-27 | 2010-06-03 | スリーエム イノベイティブ プロパティズ カンパニー | Electrolyte, electrode composition, and electrochemical cell produced therefrom |
| US7875388B2 (en) * | 2007-02-06 | 2011-01-25 | 3M Innovative Properties Company | Electrodes including polyacrylate binders and methods of making and using the same |
| JP2012069454A (en) * | 2010-09-27 | 2012-04-05 | Panasonic Corp | Nonaqueous electrolyte secondary battery |
| JP2012074167A (en) * | 2010-09-28 | 2012-04-12 | Sekisui Chem Co Ltd | Electrode for lithium ion secondary battery and manufacturing method thereof, and lithium ion secondary battery |
| JP2013222551A (en) * | 2012-04-13 | 2013-10-28 | Sumitomo Bakelite Co Ltd | Negative electrode material, negative electrode, and lithium ion secondary battery |
| JP2013222550A (en) * | 2012-04-13 | 2013-10-28 | Sumitomo Bakelite Co Ltd | Negative electrode material, negative electrode and lithium ion secondary battery |
-
2004
- 2004-07-21 JP JP2004213526A patent/JP2006032296A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007287570A (en) * | 2006-04-19 | 2007-11-01 | Iwate Univ | Lithium ion secondary battery |
| EP2122723A1 (en) * | 2007-02-06 | 2009-11-25 | 3M Innovative Properties Company | Electrodes including novel binders and methods of making and using the same |
| JP2010518581A (en) * | 2007-02-06 | 2010-05-27 | スリーエム イノベイティブ プロパティズ カンパニー | ELECTRODE CONTAINING NOVEL BINDING AGENT AND METHOD FOR PRODUCING AND USING THE SAME |
| US7875388B2 (en) * | 2007-02-06 | 2011-01-25 | 3M Innovative Properties Company | Electrodes including polyacrylate binders and methods of making and using the same |
| EP2122723B1 (en) * | 2007-02-06 | 2017-04-12 | 3M Innovative Properties Company | Electrodes including novel binders and methods of making and using the same |
| JP2010519706A (en) * | 2007-02-27 | 2010-06-03 | スリーエム イノベイティブ プロパティズ カンパニー | Electrolyte, electrode composition, and electrochemical cell produced therefrom |
| JP2009135103A (en) * | 2007-11-28 | 2009-06-18 | Samsung Sdi Co Ltd | Negative electrode for lithium secondary battery, and lithium secondary battery containing this |
| JP2012069454A (en) * | 2010-09-27 | 2012-04-05 | Panasonic Corp | Nonaqueous electrolyte secondary battery |
| JP2012074167A (en) * | 2010-09-28 | 2012-04-12 | Sekisui Chem Co Ltd | Electrode for lithium ion secondary battery and manufacturing method thereof, and lithium ion secondary battery |
| JP2013222551A (en) * | 2012-04-13 | 2013-10-28 | Sumitomo Bakelite Co Ltd | Negative electrode material, negative electrode, and lithium ion secondary battery |
| JP2013222550A (en) * | 2012-04-13 | 2013-10-28 | Sumitomo Bakelite Co Ltd | Negative electrode material, negative electrode and lithium ion secondary battery |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4963330B2 (en) | Lithium iron composite oxide for positive electrode active material of lithium secondary battery, method for producing the same, and lithium secondary battery using the same | |
| US7655356B2 (en) | Nonaqueous electrolyte secondary battery | |
| JP2004207120A (en) | Nonaqueous electrolyte secondary battery | |
| JP2008177346A (en) | Energy storage device | |
| JP2007035358A (en) | Positive electrode active substance, its manufacturing method and lithium ion secondary battery | |
| JP2008262768A (en) | Lithium ion secondary battery | |
| JPH08236155A (en) | Lithium secondary battery | |
| JPH09147913A (en) | Nonaqueous electrolyte battery | |
| JP2002025611A (en) | Nonaqueous electrolyte secondary battery | |
| JP5279567B2 (en) | Nonaqueous electrolyte secondary battery | |
| JP5586116B2 (en) | Positive electrode mixture for lithium secondary battery and use thereof | |
| JP2010009898A (en) | Nonaqueous secondary battery and nonaqueous secondary battery system | |
| JP2006032296A (en) | Negative electrode and nonaqueous electrolyte secondary battery | |
| JP2005259635A (en) | Nonaqueous electrolyte secondary battery | |
| JP2009004357A (en) | Nonaqueous electrolyte lithium-ion secondary battery | |
| JP5271751B2 (en) | Lithium ion secondary battery | |
| JP4503964B2 (en) | Nonaqueous electrolyte secondary battery | |
| JP2002151144A (en) | Lithium secondary battery | |
| JP2005142004A (en) | Non-aqueous electrolyte secondary battery | |
| JP2002313416A (en) | Non-aqueous electrolyte secondary battery | |
| JP5189466B2 (en) | Lithium secondary battery | |
| JP2000012029A (en) | Nonaqueous electrolyte secondary battery | |
| JPH11312523A (en) | Electrode for battery and nonaqueous electrolyte battery | |
| JPH08171934A (en) | Lithium secondary battery | |
| JP2002260726A (en) | Nonaqueous electrolyte secondary battery |