JP4306201B2

JP4306201B2 - Method for manufacturing three-dimensional foam substrate and electrode for alkaline storage battery

Info

Publication number: JP4306201B2
Application number: JP2002224564A
Authority: JP
Inventors: 剛太浅野; 仁三栗谷; 清人渡辺
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-08-01
Filing date: 2002-08-01
Publication date: 2009-07-29
Anticipated expiration: 2022-08-01
Also published as: JP2004071169A

Description

【０００１】
【発明の属する技術分野】
本発明は、アルカリ蓄電池に使用する正極用発泡基板に関するものであり、特に基板厚みを薄くし、芯材占有体積を減少させることにより高容量化、及び同体積で極板対向面積を増加させることで出力性能が向上するとともに、基板薄型化により切断加工時のバリと極板群巻回時に発生するクラックを抑制するため、正・負極間の内部短絡を低下させるものである。
【０００２】
【従来の技術】
近年、機器のポータブル化、コードレス化が急速に進む中、これらの電源として小型且つ、軽量で高エネルギー密度を有する二次電池への要望が高まりつつある。市場では、とくに高容量で、安価な二次電池が要望されている。このため、ニッケル−水素蓄電池やニッケル−カドミウム蓄電池などに代表されるアルカリ蓄電池のコストダウンと市場での信頼性向上が強く要望されている。
【０００３】
従来、このようなアルカリ蓄電池は、水酸化ニッケルを主活物質とする正極板と負極板と、この両者間に介在して電気的に絶縁するセパレータとを渦巻状に巻回して構成した極板群を金属製電池ケースに収納し、この極板群にアルカリ電解液が所定量注入された後、電池ケース上部を正・負いずれか一方極の端子を兼ねた封口板で密閉して構成される。
【０００４】
ここでの正極板は、水酸化ニッケルを主活物質とし、水と水溶性の結着剤とともに混練して活物質ペーストを作製し、これをニッケルからなるスポンジ状基板に充填して乾燥後、プレスして厚みを均一にするとともに活物質の充填密度を高め、小径のローラ間を通過して正極板の柔軟処理をしたものであるが、上記、構成時にクラックを生じながら巻回されており電池の容量が大きくなる程、この傾向は顕著になる。
【０００５】
電池を大電流放電させるためには、巻回時の正極板と負極板の対向する面積を増加させる必要があり、これに伴い使用する芯材量も増加する。この正・負極板の巻回時に発生するクラックを抑制するために、従来は図３に示すようにウレタンの発泡時に気泡が抜ける方向と極板群の巻回方向が垂直方向になるようにピーリングをする方法が取られていた。（特開平３−２２６９６９号公報）
【０００６】
【発明が解決しようとする課題】
上記従来の材料を用いた正極板、特に容量レベルの高いものは、その柔軟度が十分ではないため、巻回時に巻回軸芯側である電極板の内周側は圧縮され、反対に外周側は伸長されるため、特に、外周側においてクラックが生じる。このクラックがセパレータを貫通して負極板と接触し、内部短絡を発生させるという問題があった。
【０００７】
また、正極発泡基板の基材であるスポンジウレタンはピーリングする際、ポリウレタンの成形加工機であるすき機の能力限界により１ｍｍ以下の厚みにすることができないため、それ以下の厚みの芯材を得ることができない。そのため、それ以下の厚みの芯材を使用するには、２次元芯材（パンチングメタル等）を使用せざるを得なかった。
【０００８】
この２次元芯材を用いて単に活物質を塗布した場合には、活物質との導電網が十分に形成されないために電池特性を引き出すことが困難となる。また１ｍｍ以上の発泡基板をそれ以下に圧延すると骨格が破断したり、表面の空孔が塞がれ、活物質混練ペーストの浸透が悪くなったりすることがあった。
【０００９】
本発明は、上記の課題を解決するとともに、特に芯材体積増加によるコストアップと電極中の芯材体積増加による活物質占有体積の減少、つまり電池容量が減少することのない、高容量、高出力アルカリ蓄電池用電極とそれを用いた電池を提供することを目的とする。
【００１０】
【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アルカリ蓄電池用３次元発泡基板の製造方法は、スポンジウレタンを硬化する工程の次に、下記（１）の発泡する工程を行い、次に（２）のピーリングする工程を行い、次に（３）のニッケルメッキを施す工程を経て（４）の研磨加工する工程を行うか、あるいは（４）の研磨加工する工程を経て（３）のニッケルメッキを施す工程を行い、次に（５）の焼成して除去する工程を行う製造方法とした。
【００１１】
この際、下記、ピーリングする工程でスポンジウレタンの厚みを１．４〜２．０ｍｍに、研磨加工する工程でスポンジウレタンの厚みを０．５〜１．０ｍｍに、３次元発泡基板の厚みは０．２〜０．８ｍｍである事が好ましい。
【００１２】
（１）スポンジウレタンを発泡する工程。
【００１３】
（２）スポンジウレタンをピーリングする工程。
【００１４】
（３）スポンジウレタンにニッケルメッキを施す工程。
【００１５】
（４）スポンジウレタンを研磨加工する工程。
【００１６】
（５）スポンジウレタンを焼成して除去し、アルカリ蓄電池用３次元発泡基板を作成する工程。
【００１７】
（６）前記基板に水酸化ニッケルを主成分とした活物質と水との混練ペーストを充填して乾燥する工程。
【００１８】
前記（１）のスポンジウレタンを発泡する工程の前にスポンジウレタンを硬化させることにより、（２）の工程でのスポンジウレタンのピーリングや、（４）の工程でのスポンジウレタンの研磨加工が容易になる。このスポンジウレタンを硬化させる方法としては、例えば重量の割合で、スポンジウレタン１５に対してエポキシ樹脂２〜４の割合で混合させると充分な硬化度合いになり好ましい。
【００１９】
上記、製造方法の場合は（２）の工程の後に（３），（４）の工程を経て基板を製造。すなわち発泡させたスポンジウレタンをピーリングした後、ニッケルメッキを施し、研磨する事も、あるいは上記（４）の工程の後に（３）の工程を経て基板を製造。すなわち発泡させたスポンジウレタンをピーリングした後、研磨し、ニッケルメッキを施す事も可能である。
【００２０】
【発明の実施の形態】
本発明のアルカリ蓄電池用３次元発泡基板の製造方法は、スポンジウレタンを硬化する工程の次に、スポンジウレタンを発泡する工程を備え、次にスポンジウレタンを第１の厚みにピーリングする工程を備え、次にスポンジウレタンにニッケルメッキを施す工程を経てスポンジウレタンを第１の厚みより薄い第２の厚みに研磨加工する工程を備えるか、あるいはスポンジウレタンを第１の厚みより薄い第２の厚みに研磨加工する工程を経てスポンジウレタンにニッケルメッキを施す工程を備え、次にスポンジウレタンを焼成して除去する工程を備えた製造方法である。
【００２１】
この発明により、従来の発泡基板に比べて極めて薄型の３次元多孔質基板を作製することができ、活物質混練ペースト充填時の長手方向に掛かるテンションに絶えることができる上に、従来のニッケル密度以下でも生産が可能となる。したがって、芯材体積を従来の４００ｇ／ｍ²から２００ｇ／ｍ²と半減することが可能となり、その分、極板長さを延長してもコストアップにならないという利点が生じる。
【００２２】
本発明のアルカリ蓄電池用電極の製造方法は、スポンジウレタンを硬化する工程の次に、スポンジウレタンを発泡する工程を備え、次にスポンジウレタンを第１の厚みにピーリングする工程を備え、次にスポンジウレタンにニッケルメッキを施す工程と、スポンジウレタンを第１の厚みより薄い第２の厚みに研磨加工する工程を経てスポンジウレタンを第１の厚みより薄い第２の厚みに研磨加工する工程を備えるか、あるいはスポンジウレタンを第１の厚みより薄い第２の厚みに研磨加工する工程を経てスポンジウレタンにニッケルメッキを施す工程を備え、次にスポンジウレタンを焼成・除去してアルカリ蓄電池用３次元発泡基板を作製する工程と、前記基板に水酸化ニッケルを主活物質とし、水との混練ペーストを充填して乾燥する工程とを備えた製造方法である。
【００２３】
本発明で製造されたアルカリ蓄電池用電極を正極板として用い、水素吸蔵合金を塗着した芯材からなる負極板とセパレータとを渦巻状に巻回して極板群を構成することによって、従来の製造方法で得られた正極板を用いるよりも、巻回時に正極板の、主に外周側に発生するクラックや正極板切断端部のバリがセパレータを貫通して負極と接触し、内部短絡を引き起こすという現象を著しく減少させることができる。
【００２４】
上記のスポンジウレタンを用いた発泡基板にて製造した正極板は、特に高容量化、高出力化技術に寄与する。一般的に正極板と負極板が巻回方向に対向する面積が大きいほど出力特性は向上する。
【００２５】
【実施例】
以下に、本発明の具体例を説明する。
【００２６】
１インチ当たり５５個の連続気孔を有する厚さ１．６ｍｍのウレタン発泡体をグラインダー式研磨機にて厚さ０．８ｍｍまで研磨後、塩化パラジウム溶液に浸漬し、更にニッケルメッキ溶液中で電流を流し２００ｇ／ｍ²となるようにニッケルメッキを行った。次にこの多孔体を水素ガス中１０００℃で焼成し、本発明の実施例におけるニッケル発泡基板１を得た。
【００２７】
また、１インチ当たり５５個の連続気孔を有する厚さ１．６ｍｍのウレタン発泡体を塩化パラジウム溶液に浸漬し、更にニッケルメッキ溶液中で電流を流し６００ｇ／ｍ²となるようにニッケルメッキを行った。次にこの多孔体をグラインダー式研磨機にて厚さ０．８ｍｍ、密度３００ｇ／ｍ²まで研磨した後、水素ガス中１０００℃で焼成し、本発明の実施例におけるニッケル発泡基板２を得た。
【００２８】
次に、水酸化ニッケル１００重量部に対し、結着剤としてカルボキシメチルセルロース０．２重量部と、全ペーストの２５重量％となるように水を加え練合してペースト状活物質を作製した。
【００２９】
このペースト状活物質を上記ニッケル発泡基板１に充填して乾燥した後、プレスして充填密度を高め、幅４３．７ｍｍ、厚み０．２ｍｍ、長さ１４３ｍｍの本発明の実施例における正極板１を作製した。
【００３０】
同様にペースト状活物質を上記ニッケル発泡基板２に充填して乾燥した後、プレスして充填密度を高め、幅４３．７ｍｍ、厚み０．３ｍｍ、長さ１１３ｍｍの本発明の実施例における正極板２を作製した。
【００３１】
この正極板１と、水素吸蔵合金粉末をパンチングメタルからなる芯材に塗着した、幅４３．７ｍｍ、厚さ０．２ｍｍ、長さ２０４ｍｍの負極板と、この両者間に介在して電気的に絶縁するセパレータとを渦巻状に巻回して構成した極板群を鉄にニッケルメッキした電池ケースに挿入し、アルカリ電解液を注入した後、電池ケースの上部を、正極端子を兼ねた封口板で密閉して、ＡＡサイズで公称容量２０００ｍＡｈのニッケル−水素蓄電池Ａを作製した。
【００３２】
同様に正極板２と、水素吸蔵合金粉末をパンチングメタルからなる芯材に塗着した、幅４３．７ｍｍ、厚さ０．２ｍｍ、長さ２０４ｍｍの負極板とこの両者間に介在して電気的に絶縁するセパレータとを渦巻状に巻回して構成した極板群を鉄にニッケルメッキした電池ケースに挿入し、アルカリ電解液を注入した後、電池ケースの上部を、正極端子を兼ねた封口板で密閉して、ＡＡサイズで公称容量２０００ｍＡｈのニッケル−水素蓄電池Ｂを作製した。
【００３３】
更に、１インチ当たり５５個の連続気孔を有する厚さ１．６ｍｍのウレタン発泡体を塩化パラジウム溶液に浸漬し、ニッケルメッキ溶液中でメッキを行い、次に、この多孔体を水素ガス中１０００℃で焼成して得たニッケル発泡基板に水酸化ニッケル１００重量部に対し、結着剤としてカルボキシメチルセルロース０．２重量部と、全ペーストの２５重量％となるように水を加え練合してペースト状活物質を充填・乾燥した後、プレスして充填密度を高め、幅４３．７ｍｍ、厚み０．８ｍｍ、長さ７５ｍｍの従来の正極板３を作製した。
【００３４】
この正極板３と、水素吸蔵合金粉末をパンチングメタルからなる芯材に塗着した、幅４３．７ｍｍ、厚さ０．４ｍｍ、長さ１０７ｍｍの負極板と、この両者間に介在して電気的に絶縁するセパレータとを渦巻状に巻回して構成した極板群を鉄にニッケルメッキした電池ケースに挿入し、アルカリ電解液を注入した後、電池ケースの上部を、正極端子を兼ねた封口板で密閉して、ＡＡサイズで公称容量２０００ｍＡｈのニッケル−水素蓄電池Ｃを作製した。
【００３５】
上記の電池Ａ，Ｂ，Ｃをそれぞれ１００００個ずつ作製した。
【００３６】
なお、実施例の正極板１，２と従来例の正極板３の正・負極間の内部短絡を検査する為、電池Ａ，Ｂ，Ｃのそれぞれに初期の充放電を施し、２４時間２０℃で放置後、端子電圧が１．２０〜１．３５Ｖの電池を良品の検査基準として、Ａ，Ｂ，Ｃの電池をそれぞれ１００００個ずつ電圧検査した。実施例の電池Ａ，Ｂは１００００個全て１．２５〜１．２８Ｖの電圧の範囲であるのに対し、従来例の電池Ｃは、検査基準内の電圧の範囲の電池以外に１．２０Ｖより低い電圧の電池が５個も発生した上に、０．１０Ｖの電池電圧のものが１個あった。
【００３７】
この従来例の電池Ｃの電圧不良品を分解して調査すると、正極板３の外周側においてクラック又は端部のバリが発生しており、これがセパレータを突破り負極板と接触して内部短絡を引き起こしていた。
【００３８】
この従来例では、正極板３を巻回する時に巻回軸芯の内側は圧縮され、反対に外周側は伸長される。このときに、正極板に十分な柔軟性がないために、正極板の外周側は、伸長されたときにクラックが発生したものである。また、端部の切断バリについては通常切断歯は厚み方向に入りにくいため、伸長しながら切断することとなる。特に発泡基板の場合は切断部にランダムな破断骨格が露出するため厚みが薄い極板程切断歯が均一に入り端部が平滑化する傾向となる。
【００３９】
さらに、電池Ａ，Ｂ，Ｃの放電特性を比較した図を図２に示す。前述した通り正極板と負極板の対向面積が大きいほどハイレート放電特性に優れ、顕著に特性差が見られた。
【００４０】
また、対向面積を小さくしてもニッケルの目付重量を大きくすれば放電レート特性は、ほぼ同等を維持できることも確認できた。
【００４１】
ここで電池Ａは充電時の内部圧力の上昇度合が小さいことからまだ残空間に余裕があることが分かる。このため活物質をさらに補い電池Ａを更に高容量化することも可能となる。
【００４２】
【発明の効果】
以上のように本発明のアルカリ蓄電池用電極は、従来にない薄型化極板であるため、巻回時の正極板クラックを防止することができ、且つ端部のバリ発生も抑制することができる。
【００４３】
また、この正極板を用いれば低コストで更に高容量、高出力のアルカリ蓄電池を設計することができる。
【図面の簡単な説明】
【図１】本発明のアルカリ蓄電池用３次元発泡基板の製造方法を示す模式図
【図２】実施例、従来例電池の放電特性を比較した図
【図３】従来のアルカリ蓄電池用３次元発泡基板の製造方法を示す模式図
【符号の説明】
１塩化パラジウム溶液
２ニッケルメッキ溶液
３スポンジウレタン
４すき機
５研磨機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a foamed substrate for a positive electrode used for an alkaline storage battery, and in particular, to increase the capacity by reducing the thickness of the substrate and decreasing the volume occupied by the core material, and to increase the electrode plate facing area with the same volume. As a result, the output performance is improved, and the internal short circuit between the positive and negative electrodes is reduced in order to suppress the burrs during the cutting process and the cracks generated during the winding of the electrode plate group by reducing the thickness of the substrate.
[0002]
[Prior art]
In recent years, with the rapid progress of portable and cordless devices, there is a growing demand for secondary batteries that are small, lightweight, and have high energy density as these power sources. In the market, there is a demand for a secondary battery that has a particularly high capacity and is inexpensive. For this reason, there is a strong demand for cost reduction of alkaline storage batteries represented by nickel-hydrogen storage batteries, nickel-cadmium storage batteries, and the like, and improvement in market reliability.
[0003]
Conventionally, such an alkaline storage battery is an electrode plate formed by spirally winding a positive electrode plate and a negative electrode plate each having nickel hydroxide as a main active material and an electrically insulating separator interposed therebetween. The group is housed in a metal battery case, and after a predetermined amount of alkaline electrolyte is injected into the electrode plate group, the upper part of the battery case is sealed with a sealing plate that serves as either a positive or negative terminal. The
[0004]
The positive electrode plate here has nickel hydroxide as a main active material, and kneaded with water and a water-soluble binder to produce an active material paste, which is filled in a sponge-like substrate made of nickel and dried. Press to make the thickness uniform and increase the packing density of the active material and pass through the small diameter rollers to soften the positive electrode plate, but it is wound with cracks during the above configuration This tendency becomes more prominent as the battery capacity increases.
[0005]
In order to discharge a battery with a large current, it is necessary to increase the area where the positive electrode plate and the negative electrode plate face each other at the time of winding, and the amount of core material used increases accordingly. In order to suppress the cracks that occur during the winding of the positive and negative electrode plates, conventionally, as shown in FIG. 3, peeling is performed so that the bubbles are released when the urethane foams and the winding direction of the electrode plate group is vertical. The way to do was taken. (Japanese Patent Laid-Open No. 3-226969)
[0006]
[Problems to be solved by the invention]
The positive electrode plate using the above-mentioned conventional material, especially the one with a high capacity level, is not sufficiently flexible, so the inner peripheral side of the electrode plate, which is the winding shaft core side, is compressed during winding, and on the contrary Since the side is elongated, cracks occur particularly on the outer peripheral side. There was a problem that this crack penetrated the separator and contacted the negative electrode plate to cause an internal short circuit.
[0007]
Moreover, since the sponge urethane, which is the base material of the positive electrode foam substrate, cannot be reduced to a thickness of 1 mm or less due to the capacity limit of the plowing machine, which is a polyurethane molding machine, a core material having a thickness less than that is obtained. I can't. Therefore, in order to use a core material having a thickness less than that, a two-dimensional core material (such as a punching metal) has to be used.
[0008]
When an active material is simply applied using this two-dimensional core material, it is difficult to draw out battery characteristics because a conductive network with the active material is not sufficiently formed. Further, when a foamed substrate of 1 mm or more is rolled to a thickness below that, the skeleton may be broken, or the surface pores may be blocked, resulting in poor penetration of the active material kneaded paste.
[0009]
The present invention solves the above-mentioned problems, and particularly increases the cost due to the increase in the volume of the core material and decreases the active material occupied volume due to the increase in the volume of the core material in the electrode, that is, the battery capacity does not decrease, It aims at providing the electrode for output alkaline storage batteries, and a battery using the same.
[0010]
[Means for Solving the Problems]
Above, the alkali 3D foam manufacturing how the substrate storage battery of the present invention in order to achieve the object, the next step of curing the sponge urethane, a step of foaming the following (1), then (2) Next, the step of peeling is performed, and then the step of polishing (4) is performed through the step of applying nickel plating in (3), or the step of polishing is performed in (4). performed step of applying, to the next (5) firing prepared how to perform a step of removing the.
[0011]
At this time, the thickness of the sponge urethane is 1.4 to 2.0 mm in the peeling process, the thickness of the sponge urethane is 0.5 to 1.0 mm in the polishing process, and the thickness of the three-dimensional foam substrate is 0. It is preferably 2 to 0.8 mm.
[0012]
(1) A step of foaming sponge urethane.
[0013]
(2) The process of peeling sponge urethane.
[0014]
(3) A step of applying nickel plating to sponge urethane.
[0015]
(4) A step of polishing sponge urethane.
[0016]
(5) A step of baking and removing sponge urethane to create a three-dimensional foamed substrate for an alkaline storage battery.
[0017]
(6) A step of filling the substrate with a kneaded paste of an active material mainly composed of nickel hydroxide and water and drying.
[0018]
By curing the sponge urethane prior to the step of foaming the sponge urethane of the (1), (2) or sponge urethane peeling in the step of facilitating abrasive machining sponge urethane in the step (4) ing to. As a method for curing the sponge urethane, for example, it is preferable to mix the sponge urethane 15 at a ratio of epoxy resin 2 to 4 with respect to the sponge urethane 15 to obtain a sufficient degree of curing.
[0019]
Above, (3) after the step of the case of manufacturing how (2), producing the substrate through the steps of (4). That is, after peeling foamed sponge urethane, nickel plating is applied and polishing is performed, or the substrate is manufactured through the step (3) after the step (4) . That is, it is possible to peel the foamed sponge urethane, and then polish and apply nickel plating.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing a three-dimensional foamed substrate for an alkaline storage battery according to the present invention comprises a step of foaming sponge urethane after the step of curing sponge urethane, and then a step of peeling sponge urethane to a first thickness, Next, a step of polishing the sponge urethane to a second thickness thinner than the first thickness through a step of nickel plating the sponge urethane, or polishing the sponge urethane to a second thickness thinner than the first thickness is provided. The manufacturing method includes a step of nickel plating the sponge urethane through a processing step, and then a step of baking and removing the sponge urethane .
[0021]
According to the present invention, it is possible to produce a three-dimensional porous substrate that is extremely thin as compared with a conventional foamed substrate, and it is possible to eliminate the tension applied in the longitudinal direction when the active material kneaded paste is filled, and the conventional nickel density Production is also possible with: Therefore, the volume of the core material can be halved from the conventional 400 g / m ² to 200 g / m ^2, and there is an advantage that the cost does not increase even if the electrode plate length is extended accordingly.
[0022]
Producing how an alkaline storage battery electrode of the present invention, the next step of curing the sponge urethane, comprising the step of foaming the sponge urethane, then comprises a step of peeling a sponge urethane first thickness, then The process includes a step of nickel plating the sponge urethane and a step of polishing the sponge urethane to a second thickness thinner than the first thickness through a step of polishing the sponge urethane to a second thickness thinner than the first thickness. Or a process of polishing the sponge urethane to a second thickness that is thinner than the first thickness and then subjecting the sponge urethane to nickel plating, and then baking and removing the sponge urethane to produce a three-dimensional foam for alkaline storage batteries. A step of manufacturing a substrate, and a step of filling the substrate with nickel hydroxide as a main active material, filling a kneaded paste with water and drying the substrate. It is a manufacturing how equipped with.
[0023]
By using the electrode for an alkaline storage battery manufactured in the present invention as a positive electrode plate, a negative electrode plate made of a core material coated with a hydrogen storage alloy and a separator are wound in a spiral shape to form a conventional electrode plate group. than using a positive electrode plate obtained by the manufacturing how, the positive electrode plate when the winding mainly burrs of cracks and the positive electrode plate cut end that occurs on the outer peripheral side is in contact with the negative electrode through a separator, internal short-circuit Can be significantly reduced.
[0024]
The positive electrode plate manufactured by the foamed substrate using the above-mentioned sponge urethane particularly contributes to a high capacity and high output technology. In general, the larger the area where the positive electrode plate and the negative electrode plate face each other in the winding direction, the better the output characteristics.
[0025]
【Example】
Specific examples of the present invention will be described below.
[0026]
A urethane foam with a thickness of 1.6 mm having 55 continuous pores per inch is polished to a thickness of 0.8 mm with a grinder-type polishing machine, then immersed in a palladium chloride solution, and a current is applied in the nickel plating solution. Nickel plating was performed so that the flow rate was 200 g / m ² . Next, this porous body was baked at 1000 ° C. in hydrogen gas to obtain a nickel foam substrate 1 in an example of the present invention.
[0027]
In addition, a 1.6 mm thick urethane foam having 55 continuous pores per inch is dipped in a palladium chloride solution, and then nickel plating is performed so that a current is passed in the nickel plating solution to 600 g / m ^2. It was. Next, this porous body was polished to a thickness of 0.8 mm and a density of 300 g / m ² with a grinder type polishing machine, and then fired at 1000 ° C. in hydrogen gas to obtain a nickel foam substrate 2 in an example of the present invention. .
[0028]
Next, with respect to 100 parts by weight of nickel hydroxide, 0.2 parts by weight of carboxymethyl cellulose as a binder and water were added and kneaded so as to be 25% by weight of the total paste to prepare a paste-like active material.
[0029]
The paste-like active material is filled in the nickel foam substrate 1 and dried, and then pressed to increase the packing density, and the positive electrode plate 1 in the embodiment of the present invention having a width of 43.7 mm, a thickness of 0.2 mm, and a length of 143 mm. Was made.
[0030]
Similarly, the paste-like active material is filled in the nickel foam substrate 2 and dried, and then pressed to increase the packing density, and the positive electrode plate of the embodiment of the present invention having a width of 43.7 mm, a thickness of 0.3 mm, and a length of 113 mm. 2 was produced.
[0031]
The positive electrode plate 1, a negative electrode plate having a width of 43.7 mm, a thickness of 0.2 mm, and a length of 204 mm, in which a hydrogen storage alloy powder is applied to a core made of a punching metal, are electrically interposed between the two. After inserting the electrode plate group formed by winding the separator in a spiral shape into a nickel-plated battery case and injecting alkaline electrolyte, the upper part of the battery case is used as a sealing plate that also serves as the positive electrode terminal. The nickel-hydrogen storage battery A having an AA size and a nominal capacity of 2000 mAh was produced.
[0032]
Similarly, a positive electrode plate 2 and a negative electrode plate having a width of 43.7 mm, a thickness of 0.2 mm, and a length of 204 mm, in which a hydrogen-absorbing alloy powder is applied to a core made of a punching metal, are interposed between the two. After inserting the electrode plate group formed by winding the separator in a spiral shape into a nickel-plated battery case and injecting alkaline electrolyte, the upper part of the battery case is used as a sealing plate that also serves as the positive electrode terminal. Then, a nickel-hydrogen storage battery B having an AA size and a nominal capacity of 2000 mAh was produced.
[0033]
Further, a urethane foam having a thickness of 1.6 mm having 55 continuous pores per inch is immersed in a palladium chloride solution and plated in a nickel plating solution. Next, the porous body is 1000 ° C. in hydrogen gas. Paste by adding water and kneading so that 0.2 wt part of carboxymethyl cellulose as a binder and 25 wt% of the total paste with respect to 100 wt. After filling and drying the solid active material, pressing was performed to increase the packing density, and a conventional positive electrode plate 3 having a width of 43.7 mm, a thickness of 0.8 mm, and a length of 75 mm was produced.
[0034]
This positive electrode plate 3, a negative electrode plate having a width of 43.7 mm, a thickness of 0.4 mm, and a length of 107 mm, in which a hydrogen storage alloy powder is applied to a core made of a punching metal, are electrically interposed between the two. After inserting the electrode plate group formed by winding the separator in a spiral shape into a nickel-plated battery case and injecting alkaline electrolyte, the upper part of the battery case is used as a sealing plate that also serves as the positive electrode terminal. The nickel-hydrogen storage battery C having an AA size and a nominal capacity of 2000 mAh was produced.
[0035]
10,000 batteries A, B, and C were prepared.
[0036]
In addition, in order to inspect the internal short circuit between the positive and negative electrodes of the positive electrode plates 1 and 2 of the example and the positive electrode plate 3 of the conventional example, each of the batteries A, B and C was subjected to initial charge / discharge, and the temperature was kept at 20 ° C. for 24 hours. Then, a battery having a terminal voltage of 1.20 to 1.35V was used as a non-defective product inspection standard, and a voltage test was performed on 10,000 A, B, and C batteries. The batteries A and B of the examples all have a voltage range of 1.25 to 1.28V, whereas the battery C of the conventional example has a voltage range of 1.20V except for the voltage range within the inspection standard. There were 5 low voltage batteries and 1 battery voltage of 0.10V.
[0037]
This prior art by disassembling the voltage defective battery C of investigating, and burrs of cracks or edge is generated at the outer peripheral side of the positive electrode plate 3, which is an internal short circuit in contact with the negative electrode plate Ri topped separator Was causing.
[0038]
In this conventional example, when the positive electrode plate 3 is wound, the inner side of the winding axis is compressed and the outer peripheral side is expanded. At this time, since the positive electrode plate does not have sufficient flexibility, the outer peripheral side of the positive electrode plate is cracked when stretched. Further, as for the cutting burr at the end portion, the cutting teeth are usually difficult to enter in the thickness direction, so that they are cut while being elongated. In particular, in the case of a foam substrate, since a random fracture skeleton is exposed at the cut portion, the thinner the electrode plate, the more uniform the cutting teeth, and the end portion tends to become smooth.
[0039]
Furthermore, the figure which compared the discharge characteristic of battery A, B, C is shown in FIG. As described above, the larger the facing area between the positive electrode plate and the negative electrode plate, the better the high rate discharge characteristics, and a significant difference in characteristics was observed.
[0040]
It was also confirmed that even if the facing area was reduced, the discharge rate characteristics could be maintained substantially the same if the nickel weight was increased.
[0041]
Here, it can be seen that battery A still has a margin in the remaining space because the degree of increase in internal pressure during charging is small. For this reason, it becomes possible to further supplement the active material and further increase the capacity of the battery A.
[0042]
【The invention's effect】
As described above, the alkaline storage battery electrode of the present invention is an unprecedented thin electrode plate, so that it can prevent cracking of the positive electrode plate during winding and also suppress the occurrence of burrs at the end. .
[0043]
Furthermore, even higher capacity in this positive electrode plate have use a is if low cost, it is possible to design the alkaline storage battery of high output.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a method for producing a three-dimensional foamed substrate for an alkaline storage battery according to the present invention. FIG. 2 is a diagram comparing the discharge characteristics of an example battery and a conventional battery. Schematic diagram showing the substrate manufacturing method 【Explanation of symbols】
1 Palladium chloride solution 2 Nickel plating solution 3 Sponge urethane 4 Plowing machine 5 Polishing machine

Claims

Next to the step of curing the sponge urethane, the method includes the step of foaming the sponge urethane , then the step of peeling the sponge urethane to the first thickness, and then the step of applying nickel plating to the sponge urethane. A step of polishing to a second thickness that is thinner than the first thickness , or a step of applying nickel plating to the sponge urethane through a step of polishing the sponge urethane to a second thickness that is thinner than the first thickness , then method for producing an alkaline 3D foam board storage battery having a higher engineering is removed by baking the sponge urethane.

The method for producing a three-dimensional foamed substrate for an alkaline storage battery according to claim 1 , wherein the first thickness of the sponge urethane is set to 1.4 to 2.0 mm in the peeling step.

The method for producing a three-dimensional foamed substrate for an alkaline storage battery according to claim 1, wherein the second thickness of the sponge urethane is set to 0.5 mm to 1.0 mm in the polishing process.

The method for producing a three-dimensional foam substrate for an alkaline storage battery according to claim 1, wherein the thickness of the three-dimensional foam substrate is 0.2 mm to 0.8 mm.

Next to the step of curing the sponge urethane, the method includes the step of foaming the sponge urethane , then the step of peeling the sponge urethane to the first thickness, and then the step of applying nickel plating to the sponge urethane. A step of polishing to a second thickness that is thinner than the first thickness , or a step of applying nickel plating to the sponge urethane through a step of polishing the sponge urethane to a second thickness that is thinner than the first thickness Next, the sponge urethane is baked and removed to prepare a three-dimensional foamed substrate for an alkaline storage battery, and the substrate is filled with a kneaded paste of nickel hydroxide as an active material and water and dried. The manufacturing method of the electrode for alkaline storage batteries provided with the process.