JP2000353517A - Manufacture of flat battery postitive electrode - Google Patents
Manufacture of flat battery postitive electrodeInfo
- Publication number
- JP2000353517A JP2000353517A JP16328099A JP16328099A JP2000353517A JP 2000353517 A JP2000353517 A JP 2000353517A JP 16328099 A JP16328099 A JP 16328099A JP 16328099 A JP16328099 A JP 16328099A JP 2000353517 A JP2000353517 A JP 2000353517A
- Authority
- JP
- Japan
- Prior art keywords
- positive electrode
- mixture
- solution
- tetrafluoroethylene
- active material
- 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
Classifications
-
- Y02E60/12—
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ペレット状に成形
された正極を含む発電要素を、扁平形の電池容器に収容
した電池の製造法に関し、詳しくはペレット状正極の表
面及び内部における割れや欠けの発生を抑制する扁平形
電池用正極の製造法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a battery in which a power generating element including a positive electrode formed in a pellet shape is accommodated in a flat battery container, and more particularly to a method for manufacturing a battery in which a positive electrode in a pellet shape has cracks on the surface and inside. The present invention relates to a method for producing a positive electrode for a flat battery, which suppresses the occurrence of chipping.
【０００２】[0002]
【従来の技術】正極、リチウムあるいはその合金を用い
た負極、有機電解質を用いた電解液からなる発電要素
を、負極端子を兼ねる封口板、正極端子を兼ねる電池ケ
ースからなる扁平形の電池容器に収容した扁平形有機電
解質電池は、負極活物質にリチウムを用いることから、
エネルギー密度が高いという特徴を有している。この種
の電池は、機器の小型化及び軽量化が可能であるだけで
なく、高信頼性を有することから各種電子機器の主電源
やメモリーバックアップ電源として使用されている。2. Description of the Related Art A power generating element comprising a positive electrode, a negative electrode using lithium or an alloy thereof, and an electrolyte using an organic electrolyte is formed into a flat battery container comprising a sealing plate also serving as a negative electrode terminal and a battery case also serving as a positive electrode terminal. The stored flat organic electrolyte battery uses lithium as the negative electrode active material,
It has the feature of high energy density. This type of battery is used as a main power source and a memory backup power source for various electronic devices because of its high reliability, as well as miniaturization and weight reduction of the device.
【０００３】[0003]
【発明が解決しようとする課題】このような扁平形有機
電解液電池の正極は、正極活物質及び導電性物質を主体
とする導電性二酸化マンガン等の正極活物質と炭素等の
導電性物質の粉末とを混合した正極合剤を、造粒・乾燥
して顆粒状合剤とした後、これを型に充填、加圧するこ
とでペレット状に成形させる方法により作成される。ペ
レット状の正極は、合剤を加圧のみによって成形してお
り、合剤を構成する粉末相互の結着力が低い。このた
め、製造工程における振動、装置との接触あるいはペレ
ット状正極相互の衝突等によって、ペレットの一部が割
れ落ちてしまう欠けや、成形後の乾燥によりペレットの
内部及び表面に割れが生じてしまう。このような不具合
の発生を防止するためには、正極合剤の粘度を上昇させ
ると共に、粉体の結着力を増加させる必要がある。そこ
で、増粘剤ならびに結着剤として４フッ化エチレン樹脂
（ＰＴＦＥ）を溶媒中に分散させたディスパージョン溶
液を正極合剤に加えて混練した後、ペレット状に成形す
る方法が用いられている。（例えば、特開昭５５−９３
６７１号公報、特開昭５５−９６５５７号公報に記載）
上記方法により正極合剤に４フッ化エチレン樹脂を分散
させた溶液を添加した製造法では、前記欠けや割れの発
生が減少する。しかしながら、ペレット状に成形した
後、４フッ化エチレン樹脂を含む溶液が乾燥した際に、
変形や反り返りが生じてしまう。このような正極を含む
発電要素をパーツフィーダ等の供給機を用いて扁平形の
電池容器に収容する際に、ペレット状の正極における変
形や反りが生じた部分が供給機内部で引っかかり、電池
組み立て工程におけるトラブルの原因となる。The positive electrode of such a flat organic electrolyte battery includes a positive electrode active material such as conductive manganese dioxide mainly composed of a positive electrode active material and a conductive material and a conductive material such as carbon. The positive electrode mixture mixed with the powder is granulated and dried to form a granular mixture, which is then filled into a mold and pressed to be formed into a pellet. The pellet-shaped positive electrode is obtained by molding the mixture only by applying pressure, and has a low binding force between powders constituting the mixture. For this reason, due to vibrations in the manufacturing process, contact with the device, collision between the pellet-shaped positive electrodes, and the like, a portion of the pellet is broken off, or cracks are generated inside and on the surface of the pellet due to drying after molding. . In order to prevent such a problem from occurring, it is necessary to increase the viscosity of the positive electrode mixture and increase the binding force of the powder. Therefore, a method is used in which a dispersion solution in which tetrafluoroethylene resin (PTFE) as a thickener and a binder is dispersed in a solvent is added to the positive electrode mixture, kneaded, and then formed into pellets. . (For example, see JP-A-55-93)
671, JP-A-55-96557)
In the production method in which the solution in which the tetrafluoroethylene resin is dispersed in the positive electrode mixture according to the above method is added, the occurrence of the chipping or cracking is reduced. However, after forming into a pellet, when the solution containing the tetrafluoroethylene resin is dried,
Deformation and warping will occur. When a power generating element including such a positive electrode is housed in a flat battery container using a feeder such as a parts feeder, a deformed or warped portion of the pellet-shaped positive electrode is caught inside the feeder, and the battery is assembled. It causes trouble in the process.
【０００４】本発明は、ペレットに割れや欠けの発生が
無く、さらに変形や反りが生じることがない正極を提供
することを目的とする。[0004] It is an object of the present invention to provide a positive electrode which does not cause cracking or chipping of the pellet and further does not cause deformation or warpage.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、本発明の扁平形電池用正極の製造法は、粉末状の正
極活物質と、同じく粉末状にあり、導電性物質とされる
黒鉛とを混合した正極合剤に対して、４フッ化エチレン
樹脂が分散された溶液と４フッ化エチレン−６フッ化プ
ロピレン共重合樹脂が分散された溶液とが予め混合され
た混合溶液に、さらに水を加えた溶液を添加するもので
あり、４フッ化エチレン−６フッ化プロピレン共重合樹
脂が分散された溶液を用いる点、４フッ化エチレン樹
脂、及び４フッ化エチレン−６フッ化プロピレン共重合
樹脂が分散された各溶液を予め混合した混合溶液を正極
合剤に添加する点を特徴としてる。Means for Solving the Problems To achieve the above object, a method for producing a positive electrode for a flat battery according to the present invention comprises a powdery positive electrode active material and a powdery positive electrode active material. For a positive electrode mixture obtained by mixing graphite, a mixed solution in which a solution in which a tetrafluoroethylene resin is dispersed and a solution in which a tetrafluoroethylene-6-fluoropropylene copolymer resin is dispersed is previously mixed, Further, a solution to which water is added is added, and a solution in which a tetrafluoroethylene-6-fluoropropylene copolymer resin is dispersed is used. It is characterized in that a mixed solution obtained by previously mixing each solution in which the copolymer resin is dispersed is added to the positive electrode mixture.
【０００６】[0006]
【発明の実施の形態】以下、本発明の実施形態につい
て、説明する。Embodiments of the present invention will be described below.
【０００７】本発明にかかる扁平形電池用正極の製造法
は、以下に示す各工程を含むものである。すなわち、
（１） 粉末状にある正極活物質と、粉末状にあり、且
つ黒鉛を主体とする正極導電性物質とを混合し、正極合
剤を調整する工程、（２） ４フッ化エチレン樹脂が分
散された溶液と、４フッ化エチレン−６フッ化プロピレ
ン共重合樹脂が分散された溶液との混合溶液を作成し、
この混合溶液に水を加えた後、さらに混合する工程、
（３） 水が加えられた混合溶液を正極合剤に添加し、
正極合剤を混練する工程、（４） 混練された正極合剤
を造粒、乾燥し、顆粒状合剤とする工程、（５） 顆粒
状合剤を型に充填した後、加圧成形してペレット状の正
極を形成する工程、からなる。The method for manufacturing a positive electrode for a flat battery according to the present invention includes the following steps. That is,
(1) a step of mixing a powdered positive electrode active material and a powdered positive electrode conductive substance mainly composed of graphite to prepare a positive electrode mixture, and (2) dispersing a tetrafluoroethylene resin A mixed solution of the solution and the solution in which the tetrafluoroethylene-6-fluoropropylene copolymer resin is dispersed,
After adding water to the mixed solution, a step of further mixing,
(3) Add the mixed solution to which the water has been added to the positive electrode mixture,
A step of kneading the positive electrode mixture, (4) a step of granulating and kneading the kneaded positive electrode mixture into a granular mixture, and (5) a step of filling the granular mixture into a mold, followed by pressure molding. Forming a positive electrode in the form of a pellet.
【０００８】前記の製造法によれば、正極の結着剤とし
て４フッ化エチレン樹脂、及び４フッ化エチレン−６フ
ッ化プロピレン共重合樹脂を用いており、これらを単独
で使用する場合に比べ、正極活物質及び導電物質の結着
力が向上する。これによって、顆粒状合剤を加圧、成形
する段階におけるペレットの欠けや割れの発生頻度が大
幅に低下する。さらに、成形されたペレット状の正極
を、パーツフィーダー等の供給装置を用いて正極容器に
供給する工程においても、正極形状の変化、具体的には
ペレット主面における反りや潰れといった変形を生じる
ことがない。さらに、変形や反りによる供給機内部での
引っかかりが生じることがなく、製造装置の安定した操
業に寄与できる。According to the above-mentioned manufacturing method, a tetrafluoroethylene resin and a tetrafluoroethylene-6-fluoropropylene copolymer resin are used as a binder for the positive electrode, and compared with the case where these are used alone. In addition, the binding force between the positive electrode active material and the conductive material is improved. As a result, the frequency of chipping or cracking of the pellets at the stage of pressing and molding the granular mixture is significantly reduced. Furthermore, in the step of supplying the molded pellet-shaped positive electrode to the positive electrode container using a supply device such as a parts feeder, a change in the positive electrode shape, specifically, deformation such as warpage or crushing of the pellet main surface occurs. There is no. Further, the inside of the feeder due to deformation or warpage does not occur, which contributes to stable operation of the manufacturing apparatus.
【０００９】また、各樹脂が分散された溶液を正極合剤
に対して別個に添加するのではなく、予め各樹脂が分散
された溶液を混合した後、これにさらに水を加えた混合
溶液とし、この混合溶液を正極合剤へ添加している。こ
の時、正極合剤中において、前記の各樹脂からなる結着
剤の正極合剤中における分散の度合いが良好になり、合
剤を構成する粉末相互の結着力が均一化される。加え
て、起電反応に寄与しない結着剤は、顆粒状合剤中に均
一に分散されている。この顆粒状合剤を用いて正極を製
造する段階にて、作製された各ペレット状の正極の電池
特性、すなわち正極容量や放電特性の面でもバラツキが
生じない。Also, instead of separately adding the solution in which each resin is dispersed to the positive electrode mixture, a solution in which each resin is dispersed in advance is mixed, and then a mixed solution is further added with water. This mixed solution is added to the positive electrode mixture. At this time, in the positive electrode mixture, the degree of dispersion of the binder composed of each of the above resins in the positive electrode mixture is improved, and the binding force between the powders constituting the mixture is uniformized. In addition, the binder that does not contribute to the electromotive reaction is uniformly dispersed in the granular mixture. At the stage of producing a positive electrode using this granular mixture, there is no variation in the battery characteristics of each of the produced pellet-shaped positive electrodes, that is, the positive electrode capacity and discharge characteristics.
【００１０】なお、本発明において、正極合剤（正極活
物質と、正極導電性物質）に対する４フッ化エチレン−
６フッ化プロピレン共重合樹脂の重量比率が、０．５〜
６％の範囲となるように、４フッ化エチレン−６フッ化
プロピレン共重合樹脂が分散された溶液における前記共
重合樹脂の割合、および／もしくは前記の共重合樹脂が
分散された溶液の正極合剤への添加量を調整するのが好
ましい。前記の重量比率が０．５％以下の場合には、顆
粒状合剤に存在する４フッ化エチレン−６フッ化プロピ
レン共重合樹脂の絶対量が不足し、正極活物質及び正極
導電性物質の粉末相互の結着力が不足し、ペレットの強
度が不十分となる。一方、重量比率が７％以上の場合に
は、４フッ化エチレン−６フッ化プロピレン共重合樹脂
が正極合剤を形成する各粉末に溶着する量が増加してし
まう。これにより、正極活物質の各粉末においてその反
応表面を被覆してしまい、正極の反応利用率が低下する
ためである。In the present invention, in the present invention, the positive electrode mixture (positive electrode active material and positive electrode conductive material) is treated with ethylene tetrafluoride.
The weight ratio of the hexafluoropropylene copolymer resin is from 0.5 to
The proportion of the copolymer resin in the solution in which the tetrafluoroethylene-6-propylene copolymer resin is dispersed, and / or the positive electrode mixture of the solution in which the copolymer resin is dispersed so as to be in the range of 6%. It is preferable to adjust the amount added to the agent. If the weight ratio is 0.5% or less, the absolute amount of the tetrafluoroethylene-6-fluoropropylene copolymer resin present in the granular mixture becomes insufficient, and the positive electrode active material and the positive electrode conductive material The binding force between the powders is insufficient, and the strength of the pellet is insufficient. On the other hand, when the weight ratio is 7% or more, the amount of the tetrafluoroethylene-6-fluoropropylene copolymer resin deposited on each powder forming the positive electrode mixture increases. Thereby, each powder of the positive electrode active material covers the reaction surface, and the reaction utilization rate of the positive electrode decreases.
【００１１】さらに、本発明において、顆粒状合剤の粒
径は、５０〜１０００μｍの範囲に設定するのが好まし
い。これは、合剤の粒径を５０μｍより小さく設定した
場合には、ペレット状に成形を行うための金型に充填す
る際の秤量精度が悪化してしまう。このため、成形され
る正極の重量にバラツキが生じ、これに起因して電池容
量等にも悪影響を与えてしまう。また、合剤の粒径が、
１０００μｍより大きく設定された場合には、正極活物
質の比表面積が小さくなり、強負荷における放電特性を
低下させてしまう。Furthermore, in the present invention, the particle size of the granular mixture is preferably set in the range of 50 to 1000 μm. If the particle size of the mixture is set to be smaller than 50 μm, the weighing accuracy at the time of filling the mixture into a mold for forming into a pellet is deteriorated. For this reason, the weight of the formed positive electrode varies, which adversely affects the battery capacity and the like. The particle size of the mixture is
When it is set to be larger than 1000 μm, the specific surface area of the positive electrode active material becomes small, and the discharge characteristics under a heavy load are reduced.
【００１２】[0012]
【実施例】次に本発明の実施例を詳述する。Next, embodiments of the present invention will be described in detail.
【００１３】（実施例１）本実施例における扁平形電池
の断面構造を図１に示す。Embodiment 1 FIG. 1 shows a cross-sectional structure of a flat battery according to this embodiment.
【００１４】図１において、正極１は、粉末状の正極活
物質、及び粉末状の導電材、結着剤等と混練し、ペレッ
ト状に形成している。この正極１の作成方法について
は、後述する。負極２は、正極１と同様にペレット状の
外観形状を有しており、シート状のリチウム金属を円形
に打ち抜くことで形成した。セパレータ４は、保液性を
有するポリプロピレン不織布からなり、正極１と負極２
との間に配置され、有機電解液が含浸されている。有機
電解液には、非プロトン性有機溶媒であるプロピレンカ
ーボネート、及び１，２−ジメトキシエタンの混合溶媒
に、ＬｉＰＦ6 を主体とする溶質を溶解しており、所定
の濃度となるように調製した。正極１、負極２及び有機
電解液が含浸された状態にあるセパレータ４を組み合わ
せて発電要素とした。この発電要素は、正極端子を兼ね
る正極容器６、同じく負極端子を兼ねる負極容器３を絶
縁パッキング５を介して密封口された電池容器に収容し
た。In FIG. 1, a positive electrode 1 is formed into a pellet by kneading a powdery positive electrode active material, a powdery conductive material, a binder and the like. A method for forming the positive electrode 1 will be described later. The negative electrode 2 has a pellet-like external shape similarly to the positive electrode 1, and was formed by punching a sheet-like lithium metal into a circle. The separator 4 is made of a liquid-retaining polypropylene non-woven fabric, and has a positive electrode 1 and a negative electrode 2.
And the organic electrolyte is impregnated. The organic electrolytic solution, propylene carbonate is a non-protic organic solvent, and a mixed solvent of 1,2-dimethoxyethane, and dissolved solutes mainly of LiPF 6, was prepared so as to have a predetermined concentration . The power generating element was formed by combining the positive electrode 1, the negative electrode 2, and the separator 4 impregnated with the organic electrolyte. In this power generation element, a positive electrode container 6 also serving as a positive electrode terminal and a negative electrode container 3 also serving as a negative electrode terminal were accommodated in a sealed battery container via an insulating packing 5.
【００１５】次に正極１の作成方法について説明する。
本実施例においては、正極活物質として、粉末状の焼成
ＭｎＯ2 を、また導電性物質として粉末状の黒鉛を用い
た。焼成ＭｎＯ2を９４重量部に対して、黒鉛粉末を６
重量部の割合で混合した。前記の正極合剤の調整に並行
して、結着剤の調整を行う。固形分を６０重量％の比率
にて含む水性４フッ化エチレン樹脂の分散溶液２０ｇ
と、固形分を５０重量％の比率にて含む水性の４フッ化
エチレン−６フッ化プロピレン共重合樹脂の分散溶液２
０ｇとを混合、攪拌して混合溶液を作製した後、さらに
水２００ｃｃ加えて充分に混合した。得られた混合溶液
を、前記の正極合剤に添加し、これら合剤と混合溶液を
混練した。Next, a method of forming the positive electrode 1 will be described.
In this example, powdered fired MnO 2 was used as the positive electrode active material, and powdered graphite was used as the conductive material. 6 parts of graphite powder were added to 94 parts by weight of calcined MnO 2.
The parts were mixed in parts by weight. The binder is adjusted in parallel with the adjustment of the positive electrode mixture. 20 g of an aqueous tetrafluoroethylene resin dispersion containing 60% by weight of solids
And a dispersion solution 2 of an aqueous tetrafluoroethylene-6-fluoropropylene copolymer resin containing a solid content of 50% by weight.
After mixing with 0 g and stirring to prepare a mixed solution, 200 cc of water was further added and mixed well. The obtained mixed solution was added to the positive electrode mixture, and the mixture and the mixed solution were kneaded.
【００１６】結着剤の混合溶液と混練された正極合剤
を、攪拌式の造粒機によって造粒した後、破砕、分級を
施すことで正極合剤を整粒した。さらに、整粒された正
極合剤を乾燥させて、直径５０〜１０００μｍの顆粒状
合剤を得た。この顆粒状合剤は、プレス成形機によっ
て、直径１５ｍｍ、厚さ２．０ｍｍのペレット状に加圧
成形し、本実施例における正極１を得る。The positive electrode mixture kneaded with the mixed solution of the binder was granulated by a stirring granulator, and then crushed and classified to form a positive electrode mixture. Further, the sized positive electrode mixture was dried to obtain a granular mixture having a diameter of 50 to 1000 μm. This granulated mixture is press-formed into a pellet having a diameter of 15 mm and a thickness of 2.0 mm by a press forming machine to obtain the positive electrode 1 in this example.
【００１７】上記行程を経て得られた正極１を、図１に
示す構成を有する発電要素及び電池容器に適用し、扁平
形電池を作成した。これを電池Ａとする。The positive electrode 1 obtained through the above process was applied to a power generating element and a battery container having the configuration shown in FIG. 1 to produce a flat battery. This is called battery A.
【００１８】（比較例１）比較例１として、実施例１と
同様に正極活物質として粉末状の焼成ＭｎＯ2 を、導電
性物質として粉末状の黒鉛を使用し、これらを９４重量
部、６重量部の割合で混合した正極合剤を調整した。ま
た、結着剤として固形分を６０重量％の比率にて含む水
性４フッ化エチレン樹脂の分散溶液を用いた。Comparative Example 1 As Comparative Example 1, powdered calcined MnO 2 was used as the positive electrode active material and powdered graphite was used as the conductive material in the same manner as in Example 1, and 94 parts by weight of these were used. A positive electrode mixture mixed at a ratio of parts by weight was prepared. Further, a dispersion solution of an aqueous tetrafluoroethylene resin containing a solid content at a ratio of 60% by weight was used as a binder.
【００１９】調整された正極合剤１０００ｇに、水２０
０ｃｃを加えた後、さらに結着剤の分散溶液を４０ｇを
添加して混練した。これに造粒及び整粒を施した後、乾
燥を行い直径５０〜１０００μｍの顆粒状合剤を作成し
た後、この顆粒状合剤をプレス成形機によって、直径１
５ｍｍ、厚さ２．０ｍｍのペレット状に加圧成形された
正極を用いて、実施例１と同様に図１に示す扁平形電池
を構成した。これを、電池Ｂとする。Water (20 g) was added to 1000 g of the prepared positive electrode mixture.
After adding 0 cc, 40 g of a binder dispersion was further added and kneaded. After granulation and sizing, the mixture is dried to prepare a granulated mixture having a diameter of 50 to 1000 μm.
A flat battery shown in FIG. 1 was constructed in the same manner as in Example 1 using a positive electrode formed into a pellet having a thickness of 5 mm and a thickness of 2.0 mm by pressure. This is called battery B.
【００２０】（比較例２）比較例２として、実施例１と
同様に正極活物質として粉末状の焼成ＭｎＯ2 を、導電
性物質として粉末状の黒鉛を使用し、これらを９４重量
部、６重量部の割合で混合した正極合剤を調整した。ま
た結着剤として、固形分を６０重量％の比率にて含む水
性４フッ化エチレン樹脂の分散溶液と、固形分を５０重
量％の比率にて含む水性４フッ化エチレン−６フッ化プ
ロピレン共重合樹脂の分散溶液を用いた。Comparative Example 2 As Comparative Example 2, powdered calcined MnO 2 was used as the positive electrode active material and powdered graphite was used as the conductive material in the same manner as in Example 1, and 94 parts by weight of these were used. A positive electrode mixture mixed at a ratio of parts by weight was prepared. As a binder, a dispersion solution of an aqueous tetrafluoroethylene resin containing a solid content at a ratio of 60% by weight and an aqueous tetrafluoroethylene-6-fluoropropylene solution containing a solid content at a ratio of 50% by weight are used. A dispersion solution of a polymer resin was used.
【００２１】調整された正極合剤１０００ｇに対して、
４フッ化エチレン樹脂の分散溶液２０ｇ、水２００ｃｃ
をそれぞれ加え、充分に混合した。この後、さらに４フ
ッ化エチレン−６フッ化プロピレン共重合樹脂の分散溶
液を５０ｇを添加し、さらに混練した。これに造粒及び
整粒を施した後、乾燥を行い直径５０〜１０００μｍの
顆粒状合剤を作成した後、この顆粒状合剤をプレス成形
機によって、直径１５ｍｍ、厚さ２．０ｍｍのペレット
状に加圧成形された正極を用いて、実施例１と同様に図
１に示す扁平形電池を構成した。これを、電池Ｃとす
る。For 1000 g of the adjusted positive electrode mixture,
20 g of a dispersion solution of tetrafluoroethylene resin, 200 cc of water
Were added and mixed well. Thereafter, 50 g of a dispersion solution of a tetrafluoroethylene-6-fluoropropylene copolymer resin was further added and kneaded. After granulation and sizing, the granules are dried to prepare a granulated mixture having a diameter of 50 to 1000 μm, and the granulated mixture is formed into a pellet having a diameter of 15 mm and a thickness of 2.0 mm by a press molding machine. A flat battery shown in FIG. 1 was constructed in the same manner as in Example 1 using the positive electrode molded in a pressurized shape. This is called battery C.
【００２２】実施例１、比較例において作成された各正
極、及びこれら正極を用いて構成された電池Ａ〜電池Ｃ
を用いて、正極の機械的強度、さらに構成された電池の
放電特性について検討を行った。ここにおいて、正極の
機械的強度を検討するための指標としては、落下試験に
て評価を行った。Each positive electrode prepared in Example 1 and Comparative Example, and batteries A to C constructed using these positive electrodes
Was used to study the mechanical strength of the positive electrode and the discharge characteristics of the constructed battery. Here, as an index for examining the mechanical strength of the positive electrode, evaluation was performed by a drop test.
【００２３】（１） 落下試験 実施例１及び比較例におけるペレット状の各正極を、そ
れぞれ１００個ずつ作成した。さらに、これを２５０℃
の温度雰囲気下に１０時間保持することによって乾燥を
施した。落下試験は、乾燥処理が施されたペレット状の
正極を、３０ｃｍの高さから、鉄板上に自由落下させて
行い、落下時の衝撃によりペレット状の正極に生じた変
形、及び割れや欠けの数を計数した。落下試験の結果を
（表１）に示す。(1) Drop Test 100 positive electrodes in the form of pellets in Example 1 and Comparative Example were prepared. In addition, this is
At 10 ° C. for 10 hours for drying. The drop test is performed by dropping the dried positive electrode in the form of a pellet on an iron plate from a height of 30 cm. The number was counted. The results of the drop test are shown in (Table 1).
【００２４】[0024]
【表１】 [Table 1]
【００２５】（表１）より明らかなように実施例１にお
いて作製されたペレットは、比較例におけるペレットに
比較して、落下試験にて割れや変形の発生数が少ないこ
とが読みとれる。このことから、実施例１にかかるペレ
ット状の正極は、比較例での正極に比べて、高い機械的
強度を有する。As is clear from Table 1, it can be seen that the pellets produced in Example 1 had a smaller number of cracks and deformations in the drop test than the pellets in Comparative Example. For this reason, the pellet-shaped positive electrode according to Example 1 has higher mechanical strength than the positive electrode in the comparative example.
【００２６】実施例１における正極の機械的強度が改善
される理由としては、結着材として４フッ化エチレン−
６フッ化プロピレン共重合樹脂を用いることにより、正
極合剤を形成する粉末相互が溶着されるために、強度が
向上している。このことは、４フッ化エチレン樹脂を単
独にて添加した比較例１の正極に対する落下試験の結果
との比較によって裏付けられる。The reason why the mechanical strength of the positive electrode in Example 1 is improved is that tetrafluoroethylene-ethylene is used as the binder.
By using the hexafluoropropylene copolymer resin, the powders forming the positive electrode mixture are welded to each other, so that the strength is improved. This is supported by a comparison with the results of a drop test on the positive electrode of Comparative Example 1 in which the tetrafluoroethylene resin was solely added.
【００２７】この点に加えて、予め４フッ化エチレン樹
脂、及び４フッ化エチレン−６フッ化プロピレン共重合
樹脂がそれぞれ分散された溶液を混ぜ合わせた混合溶液
に、さらに水を添加した状態において、正極合剤中に加
えることによって、正極合剤の内部に４フッ化エチレン
樹脂がクモの巣状に広がり、さらに同時に４フッ化エチ
レン−６フッ化プロピレン共重合樹脂も正極合剤中に分
散するために、機械的強度が向上したと考えられる。[0027] In addition to this point, in a state where water is further added to a mixed solution obtained by mixing a solution in which a tetrafluoroethylene resin and a tetrafluoroethylene-6-fluoropropylene copolymer resin are previously dispersed, respectively. , By adding it into the positive electrode mixture, the tetrafluoroethylene resin spreads in a spider web inside the positive electrode mixture, and at the same time, the tetrafluoroethylene-6-fluoropropylene copolymer resin is also dispersed in the positive electrode mixture. In addition, it is considered that the mechanical strength was improved.
【００２８】これに対して比較例２は、４フッ化エチレ
ン樹脂が分散された溶液を正極合剤に添加し、充分に混
合した後に、４フッ化エチレン−６フッ化プロピレン共
重合樹脂が分散された溶液を添加している。このため、
４フッ化エチレン−６フッ化プロピレン共重合樹脂の正
極合剤中への結着剤の分散が充分でなくなることに加え
て、先に添加された４フッ化エチレン樹脂が合剤中へク
モの巣状に広がり、後で添加される４フッ化エチレン−
６フッ化プロピレン共重合樹脂の合剤中での拡散を阻害
したため、４フッ化エチレン−６フッ化プロピレン共重
合樹脂の添加による効果が充分に発揮されなかったと考
えられる。On the other hand, in Comparative Example 2, the solution in which the tetrafluoroethylene resin was dispersed was added to the positive electrode mixture, and after sufficient mixing, the tetrafluoroethylene-6-fluoropropylene copolymer resin was dispersed. The solution was added. For this reason,
In addition to the insufficient dispersion of the binder in the positive electrode mixture of the tetrafluoroethylene-hexafluoropropylene copolymer resin, the previously added tetrafluoroethylene resin forms a spider web in the mixture. And the tetrafluoroethylene added later
It is considered that the effect of the addition of the tetrafluoroethylene-6-fluoropropylene copolymer resin was not sufficiently exerted because the diffusion of the hexafluoropropylene copolymer resin in the mixture was inhibited.
【００２９】（２） 放電実験 次に前記の実施例１及び比較例における電池Ａ〜電池Ｃ
を、それぞれ１００個づつ作製した。各電池に対して、
２０℃の環境下において、１ｋΩの負荷抵抗に接続して
連続放電を行い、電池電圧が２．０Ｖに達するまで放電
を継続した。この放電において、２．０Ｖに達するまで
の放電容量から、正極容量の利用率を算出した。得られ
た正極の利用率を（表２）に示す。(2) Discharge Experiment Next, the batteries A to C in the above-mentioned Example 1 and Comparative Example
Was manufactured 100 pieces each. For each battery,
Under an environment of 20 ° C., the battery was connected to a load resistance of 1 kΩ to perform continuous discharge, and the discharge was continued until the battery voltage reached 2.0 V. In this discharge, the utilization rate of the positive electrode capacity was calculated from the discharge capacity until reaching 2.0 V. The utilization rate of the obtained positive electrode is shown in (Table 2).
【００３０】[0030]
【表２】 [Table 2]
【００３１】（表２）より明らかなように実施例の電池
Ａは、比較例の電池Ｂ、Ｃとほぼ同等の正極利用率とな
った。従って、正極合剤に添加される結着剤の種類、及
び添加順序の相違によって、正極の利用率は影響を受け
ないことが考えられる。As is clear from Table 2, the battery A of the example had almost the same positive electrode utilization as the batteries B and C of the comparative example. Therefore, it is considered that the utilization rate of the positive electrode is not affected by the type of the binder added to the positive electrode mixture and the difference in the order of addition.
【００３２】尚、本実施例ではペレット状の正極を構成
する正極活物質に、ＭｎＯ2 を用いたが、これに代えて
Ｖ2 Ｏ5 、ＣｕＯ2 等の粉末状の活物質を用いても良
い。In the present embodiment, MnO 2 was used as the positive electrode active material constituting the positive electrode in the form of a pellet. Alternatively, a powdery active material such as V 2 O 5 or CuO 2 may be used instead. good.
【００３３】[0033]
【発明の効果】以上のように、本発明の扁平形電池用正
極の製造法は、正極活物質と正極導電性物質である黒鉛
を混合した後、さらに結着剤としてポリテトラオロエチ
レンのディスパージョン溶液と４フッ化エチレン−６フ
ッ化プロピレン共重合樹脂を分散した溶液を混合し、こ
れを正極合剤に添加する工程としている。これにより、
正極の利用率を悪化させることなく、正極の機械的強度
を大幅に向上させており、自動供給機を用いての電池容
器へ正極を挿入する工程において、ペレットの変形等の
発生を抑制し、扁平形電池の生産性を大幅に向上させる
ものである。As described above, the method of manufacturing a positive electrode for a flat battery according to the present invention comprises mixing a positive electrode active material and graphite which is a positive electrode conductive material, and further dispersing polytetrafluoroethylene as a binder. In this step, a solution in which the J.Sol. Solution and the tetrafluoroethylene-6-fluoropropylene copolymer resin are dispersed is mixed, and the mixed solution is added to the positive electrode mixture. This allows
Without deteriorating the utilization rate of the positive electrode, the mechanical strength of the positive electrode has been significantly improved, and in the step of inserting the positive electrode into the battery container using an automatic feeder, the occurrence of deformation of the pellet and the like is suppressed, This greatly improves the productivity of flat batteries.
【図１】本実施例における扁平形電池の断面構造を示す
図FIG. 1 is a diagram showing a cross-sectional structure of a flat battery according to an embodiment.
１ 正極 ２ 負極 ３ 負極容器 ４ セパレータ ５ 絶縁パッキング ６ 正極容器 Reference Signs List 1 positive electrode 2 negative electrode 3 negative electrode container 4 separator 5 insulating packing 6 positive electrode container
Claims (3)
電性物質とを混合し、正極合剤を形成する工程、４フッ
化エチレン樹脂が分散された溶液と、４フッ化エチレン
−６フッ化プロピレン共重合樹脂が分散された溶液とを
混合して混合溶液とし、この混合溶液に水を添加してさ
らに混合する工程、水が添加された混合溶液を該正極合
剤に添加し、正極合剤を混練する工程、混練された正極
合剤を造粒、乾燥し、顆粒状合剤とする工程、顆粒状合
剤を型に充填した後、加圧成形してペレット状の正極を
形成する工程、からなる扁平形電池用正極の製造法。A step of mixing a positive electrode active material and a positive electrode conductive substance mainly composed of graphite to form a positive electrode mixture; a solution in which a tetrafluoroethylene resin is dispersed; Mixing the solution in which the fluorinated propylene copolymer resin is dispersed to form a mixed solution, adding water to the mixed solution and further mixing, adding the mixed solution to which the water has been added to the positive electrode mixture, The step of kneading the positive electrode mixture, the step of granulating and kneading the kneaded positive electrode mixture, the step of forming a granular mixture, and filling the mold with the granular mixture, followed by pressure molding to form a pellet-shaped positive electrode. Forming a positive electrode for a flat battery.
４フッ化エチレン−６フッ化プロピレン共重合樹脂の重
量比率が、０．５〜６重量％である請求項１記載の扁平
形電池用正極の製造法。2. The positive electrode for a flat battery according to claim 1, wherein the weight ratio of the ethylene tetrafluoride-6-propylene copolymer resin to the positive electrode active material and the positive electrode conductive material is 0.5 to 6% by weight. Manufacturing method.
ｍである請求項１記載の扁平形電池用正極の製造法。3. The particle size of the granular mixture is 50 to 1000 μm.
2. The method for producing a positive electrode for a flat battery according to claim 1, wherein m is m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16328099A JP2000353517A (en) | 1999-06-10 | 1999-06-10 | Manufacture of flat battery postitive electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16328099A JP2000353517A (en) | 1999-06-10 | 1999-06-10 | Manufacture of flat battery postitive electrode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000353517A true JP2000353517A (en) | 2000-12-19 |
Family
ID=15770825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16328099A Pending JP2000353517A (en) | 1999-06-10 | 1999-06-10 | Manufacture of flat battery postitive electrode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000353517A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004051770A1 (en) * | 2002-12-05 | 2004-06-17 | Tdk Corporation | Coating liquid for electrode formation, electrode, electrochemical element and process for producing these |
| JP2005310522A (en) * | 2004-04-21 | 2005-11-04 | Matsushita Electric Ind Co Ltd | Manufacturing method of nonaqueous electrolytic solution battery |
| US7655355B2 (en) * | 2001-07-04 | 2010-02-02 | Panasonic Corporation | Positive electrode binder for alkaline storage battery |
| JP2020149828A (en) * | 2019-03-13 | 2020-09-17 | セイコーインスツル株式会社 | Positive electrode for coin-type nonaqueous electrolyte secondary battery and coin-type nonaqueous electrolyte secondary battery including the same, and manufacturing method of positive electrode for coin-type nonaqueous electrolyte secondary battery |
-
1999
- 1999-06-10 JP JP16328099A patent/JP2000353517A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7655355B2 (en) * | 2001-07-04 | 2010-02-02 | Panasonic Corporation | Positive electrode binder for alkaline storage battery |
| US7887953B2 (en) | 2001-07-04 | 2011-02-15 | Panasonic Corporation | Positive electrode for alkaline storage battery |
| WO2004051770A1 (en) * | 2002-12-05 | 2004-06-17 | Tdk Corporation | Coating liquid for electrode formation, electrode, electrochemical element and process for producing these |
| JP2004186089A (en) * | 2002-12-05 | 2004-07-02 | Tdk Corp | Coating liquid for electrode formation, electrode and electrochemical element, and manufacturing method of coating liquid for electrode formation, manufacturing method of electrode and manufacturing method of electrochemical element |
| JP2005310522A (en) * | 2004-04-21 | 2005-11-04 | Matsushita Electric Ind Co Ltd | Manufacturing method of nonaqueous electrolytic solution battery |
| JP2020149828A (en) * | 2019-03-13 | 2020-09-17 | セイコーインスツル株式会社 | Positive electrode for coin-type nonaqueous electrolyte secondary battery and coin-type nonaqueous electrolyte secondary battery including the same, and manufacturing method of positive electrode for coin-type nonaqueous electrolyte secondary battery |
| JP7170563B2 (en) | 2019-03-13 | 2022-11-14 | セイコーインスツル株式会社 | Positive electrode for coin-shaped non-aqueous electrolyte secondary battery, coin-shaped non-aqueous electrolyte secondary battery using the same, and method for manufacturing positive electrode for coin-shaped non-aqueous electrolyte secondary battery |
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