JP3745583B2

JP3745583B2 - Nickel positive electrode plate for alkaline storage battery and manufacturing method thereof

Info

Publication number: JP3745583B2
Application number: JP2000118384A
Authority: JP
Inventors: 雅義丸田; 芳幸村岡; 真澄勝本; 史彦吉井
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1999-06-30
Filing date: 2000-04-19
Publication date: 2006-02-15
Anticipated expiration: 2020-04-19
Also published as: JP2001076717A

Description

【０００１】
【発明の属する技術分野】
本発明は、ニッケル−カドミウム蓄電池、ニッケル−水素蓄電池などのアルカリ蓄電池に用いるニッケル正極板およびその製造法に関する。
【０００２】
【従来の技術】
近年、アルカリ蓄電池は、用途が拡大するにつれて、軽量化、小型化、および高性能化が要求されている。その中でも電気自動車等に用いられるニッケル正極板については、急速充放電が可能であり、高温での活物質利用率が高く、かつサイクル寿命の長いものが要求されている。
一般に急速充放電用アルカリ蓄電池の正極板は、内部抵抗が小さくサイクル特性に優れた焼結式ニッケル電極が用いられてきた。この焼結式ニッケル電極は、高温での活物質利用率を向上するため、カドミウムやコバルトが添加されていた。
しかし、近年環境保全の立場から、カドミウム化合物の使用に対する規制が高まりつつある。また、水素吸蔵合金を主体とする負極を使用したニッケル−水素蓄電池では、正極中に添加したカドミウム化合物が充放電サイクル中に移動して負極表面を覆い、充放電における負極の阻害要因となることも知られている。
【０００３】
一方、正極板にコバルト化合物を添加する方法は、十分な特性を確保するためには、高価なコバルトを多量に添加する必要がある。また、多量に添加されたコバルトにより放電時の電圧が低下するという問題点もある。
そこで、特開昭４８−５０２３３号公報等に開示されているように水酸化イットリウムなどのイットリウム化合物をニッケル正極板に添加することによって、常温における活物質の利用率を低下させることなく、高温での活物質利用率を向上することが提案されている。水酸化イットリウムを添加した正極は、例えばニッケル焼結基板をニッケル塩とイットリウム塩を含む酸性水溶液に浸漬し、乾燥し、ついで、アルカリ水溶液に浸漬してニッケル塩とイットリウム塩を水酸化物に転換させる一連の処理を、活物質量が所望される量になるまで繰り返すことによって製造することができる。
【０００４】
【発明が解決しようとする課題】
しかしながら、この方法によると、イットリウム量が多くなり、またニッケル水酸化物とイットリウム水酸化物とを混合状態で生成させるので見かけ比重が低いことから、高容量密度の極板を得ることはできないという問題点があった。
本発明は、適量のイットリウム化合物およびコバルト化合物を使用することにより、放電時の作動電圧の低下を抑制するとともに、高温での活物質の利用率の高い、高容量密度のアルカリ蓄電池用焼結式ニッケル正極板を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明のニッケル正極板は、多孔性ニッケル焼結基板、および前記基板に充填されたニッケル水酸化物を主体とする金属水酸化物からなる正極板であって、前記水酸化物が、イットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の水酸化物からなり前記基板に接している第１層、ニッケル水酸化物とコバルト水酸化物との混合物からなり前記第１層を覆う第２層、およびコバルト水酸化物からなり前記第２層を覆う第３層からなる。
ここにおいて、ニッケル水酸化物１００重量部に対して、第１層のイットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の水酸化物の量が１〜４重量部、第２層のコバルト水酸化物が１〜５重量部、第３層のコバルト水酸化物の量が３〜６重量部である。
さらに第２層が、亜鉛水酸化物を含むことが好ましい。第２層の亜鉛水酸化物の量は、ニッケル水酸化物１００重量部に対して３〜６重量部であることが好ましい。
【０００６】
本発明は、（１）多孔性のニッケル焼結基板をイットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の塩の酸性水溶液に浸漬し、乾燥し、ついでアルカリ水溶液に浸漬して前記塩を水酸化物に転換させる操作を少なくとも一回行うことにより、前記基板の細孔内にイットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の水酸化物からなる第１層を形成する工程、（２）前記基板をニッケル塩とコバルト塩を含む酸性水溶液に浸漬し、乾燥し、ついでアルカリ水溶液に浸漬してニッケル塩とコバルト塩をそれぞれ水酸化ニッケルと水酸化コバルトに転換させる操作を少なくとも一回行うことにより、前記基板の第１層の上側にニッケル水酸化物とコバルト水酸化物との混合物からなる第２層を形成する工程、および（３）前記の基板をコバルト塩水溶液に浸漬し、乾燥し、ついでアルカリ水溶液に浸漬して、コバルト塩をコバルト水酸化物に転換させる操作を少なくとも一回行うことにより、第２層の上側にコバルト水酸化物からなる第３層を形成する工程を有するニッケル正極板の製造法を提供する。ここで、得られた正極板において、ニッケル水酸化物１００重量部に対して、第１層の水酸化物の量が１〜４重量部、第２層のコバルト水酸化物の量が１〜５重量部、第３層のコバルト水酸化物の量が３〜６重量部である。
【０００７】
本発明は、（１）多孔性のニッケル焼結基板をイットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の塩の酸性水溶液に浸漬し、乾燥し、ついでアルカリ水溶液に浸漬して前記塩を水酸化物に転換させる操作を少なくとも一回行うことにより、前記基板の細孔内にイットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の水酸化物からなる第１層を形成する工程、（２）前記基板をニッケル塩、コバルト塩および亜鉛塩を含む酸性水溶液に浸漬し、乾燥し、ついでアルカリ水溶液に浸漬してニッケル塩、コバルト塩および亜鉛塩をそれぞれ水酸化ニッケル、水酸化コバルトおよび水酸化亜鉛に転換させる操作を少なくとも一回行うことにより、前記基板の第１層の上側にニッケル水酸化物、コバルト水酸化物および亜鉛水酸化物の混合物からなる第２層を形成する工程、および（３）前記の基板をコバルト塩水溶液に浸漬し、乾燥し、ついでアルカリ水溶液に浸漬して、コバルト塩をコバルト水酸化物に転換させる操作を少なくとも一回行うことにより、第２層の上側にコバルト水酸化物からなる第３層を形成する工程を有するニッケル正極板の製造法を提供する。ここで、得られたニッケル正極板において、ニッケル水酸化物１００重量部に対して、第１層の水酸化物の量が１〜４重量部、第２層のコバルト水酸化物の量が１〜５重量部、第２層の亜鉛水酸化物の量が３〜６重量部、第３層のコバルト水酸化物の量が３〜６重量部である。
【０００８】
【発明の実施の形態】
本発明によるニッケル正極板は、上記のように、焼結ニッケル基板の細孔内に３層の金属水酸化物層が形成されている。第１層は、焼結基板の骨格を形成するニッケル金属の表面を覆う水酸化物の層で、イットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の水酸化物からなる。第２層は、活物質のニッケル水酸化物と導電剤のコバルト水酸化物との混合からなる。第３層は、コバルト水酸化物の層である。焼結基板の骨格を形成するニッケル金属の表面はイットリウム、イッテルビウムおよびルテチウムからなる群より選ばれた少なくとも一種の元素の水酸化物で覆われているので、電極の酸素発生電位が高くなる。第２層に含まれる活物質のニッケル水酸化物は、導電剤であるコバルト水酸化物と混合されて第１層を覆い、さらにこの第２層の上側が少量の導電性の高いコバルト水酸化物からなる第３層で覆われている。このため、放電時の作動電圧の低下が抑制され、４０℃以上の高温においても正極活物質の利用率が高い。
【０００９】
上記の正極板は、活物質のニッケル水酸化物１００重量部に対して、基板を構成するニッケルの表面を覆っている第１層の水酸化物の量は１〜４重量部、その上側を覆っている第２層のニッケル水酸化物とコバルト水酸化物との混合物中のコバルト水酸化物の量は１〜５重量部、さらにその上側を覆っている第３層のコバルト水酸化物の量は３〜６重量部である。
第１層の水酸化物の量が１重量部未満、第２層中のコバルト水酸化物の量が１重量部未満、第３層のコバルト水酸化物の量が３重量部未満であると、それらの添加効果が十分表れない。また、第１層の水酸化物の量が４重量部、第２層中のコバルト水酸化物の量が５重量部、第３層のコバルト水酸化物の量が６重量部をそれぞれ越えると、活物質の水酸化ニッケルの量が相対的に減少し、容量密度が不満足となる。
活物質のニッケル水酸化物を含む第２層が、さらに亜鉛水酸化物を含むと、電池を過充電したときの正極板の膨潤を防ぐことができる。これにより、セパレータ中の電解液量の変動がなくなり、電池の充放電サイクル寿命が伸びる。
【００１０】
【実施例】
以下、本発明の実施例について説明する。
【００１１】
《実施例１》
還元性雰囲気中で焼結した多孔度約８５％のニッケル焼結基板を準備した。この基板を、温度３０℃、ｐＨ２．５、濃度０．３モル／ｌの硝酸イットリウム水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させることにより、基板の細孔中へイットリウム塩を保持させた。次いで、前記の基板を温度８０℃の水酸化ナトリウムの２５％水溶液中に浸漬することにより、前記イットリウム塩を水酸化イットリウムに転換させ、ついで、充分に水洗してアルカリ溶液を除去し、８０℃の温度雰囲気下で充分乾燥した。こうしてニッケル焼結基板の細孔内に水酸化イットリウム層を形成した。
ついで、この基板を、温度８０℃、ｐＨ１．５で、硝酸ニッケル５．５モル／ｌと硝酸コバルト０．０６モル／ｌを含む水溶液に浸漬し、８０℃の温度で充分乾燥させることにより、基板の細孔内へニッケル塩およびコバルト塩の混合物を保持させた。次に、前記の基板を温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬することにより、ニッケル塩およびコバルト塩をそれぞれ水酸化ニッケルおよび水酸化コバルトに転換させ、ついで、充分に水洗してアルカリ溶液を除去し、乾燥するという一連の活物質充填操作を７回繰り返した。こうして基板を覆っている水酸化イットリウム層の上側に水酸化ニッケルと水酸化コバルトの混合物の層を形成した。
【００１２】
さらに、この基板を温度３０℃、ｐＨ２．５、濃度４．０モル／ｌの硝酸コバルト水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させることにより、基板の細孔へコバルト塩を保持させた。次に、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬することにより、コバルト塩を水酸化コバルトに転換させ、ついで、充分に水洗してアルカリ溶液を除去した。こうして水酸化ニッケルと水酸化コバルトの混合物の層の上に水酸化コバルトの層を形成した。
以上のようにしてニッケル正極板を得た。これをａ１とする。
【００１３】
《実施例２》
実施例１と同じ多孔度約８５％のニッケル焼結基板を、温度３０℃、ｐＨ２．５、濃度０．３モル／ｌの硝酸イットリウム水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させた後、温度８０℃、２５％の水酸化ナトリウム水溶液中に浸漬し、イットリウム塩を水酸化イットリウムに転換させ、ついで、充分に水洗を行いアルカリ溶液を除去し、８０℃の温度雰囲気下で充分乾燥して、ニッケル焼結基板の細孔内に水酸化イットリウム層を形成した。
ついでこの基板を、温度８０℃、ｐＨ１．５で、硝酸ニッケル５．５モル／ｌと硝酸コバルト０．０６モル／ｌと硝酸亜鉛０．０８モル／ｌを含む水溶液に浸漬し、８０℃の温度で充分乾燥させた後、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬し、ニッケル塩、コバルト塩および亜鉛塩をそれぞれ水酸化ニッケル、水酸化コバルトおよび水酸化亜鉛に転換させ、ついで、充分に水洗を行いアルカリ溶液を除去して、乾燥を行う一連の活物質充填操作を７回繰り返し、水酸化イットリウム層の上側に水酸化ニッケルと水酸化コバルトと水酸化亜鉛の混合物の層を形成した。
【００１４】
さらに、この極板を、３０℃、ｐＨ２．５、濃度４．０モル／ｌの硝酸コバルト水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させた後、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬し、コバルト塩を水酸化コバルトに転換させ、ついで、充分に水洗を行いアルカリ溶液を除去した。こうして本実施例のニッケル正極板ａ２を作製した。
【００１５】
《比較例１》
実施例１と同じ多孔度約８５％のニッケル焼結基板を、温度８０℃、ｐＨ１．５で硝酸ニッケル５．５モル／ｌと硝酸コバルト０．０６モル／ｌを含む水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させた後、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬し、ニッケル塩およびコバルト塩をそれぞれ水酸化ニッケルおよび水酸化コバルトに転換させ、ついで、充分に水洗を行いアルカリ溶液を除去し、乾燥する一連の活物質充填操作を７回繰り返した。こうして基板の細孔内に水酸化ニッケルと水酸化コバルトの混合物からなる層を形成した。
ついで、この極板を、温度３０℃、ｐＨ２．５、濃度４．０モル／ｌの硝酸コバルト水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させた後、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬し、コバルト塩を水酸化コバルトに転換させ、ついで、充分に水洗をしてアルカリ溶液を除去した。こうして得た比較例１のニッケル正極板をｂとする。
【００１６】
《比較例２》
実施例１と同じ多孔度約８５％のニッケル焼結基板を、温度３０℃、ｐＨ２．５、濃度１モル／ｌの硝酸コバルト水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させた後、温度８０℃、２５％の水酸化ナトリウム水溶液中に浸漬し、コバルト塩を水酸化コバルトに転換させ、充分に水洗を行いアルカリ溶液を除去して、ニッケル焼結基板の細孔内に水酸化コバルトの層を形成した。
この基板を、温度８０℃、ｐＨ１．５で硝酸ニッケル５．５モル／ｌと硝酸コバルト０．０６モル／ｌを含む水溶液に浸漬し、８０℃で充分乾燥させた後、８０℃、２５％の水酸化ナトリウム水溶液中に浸漬し、ニッケル塩およびコバルト塩をそれぞれ水酸化ニッケルおよび水酸化コバルトに転換させ、ついで、充分に水洗を行いアルカリ溶液を除去し、乾燥する一連の活物質充填操作を７回繰り返し、水酸化ニッケルと水酸化コバルトの混合物からなる層を形成した。
次に、この極板を、温度３０℃、ｐＨ２．５、濃度４．０モル／ｌの硝酸コバルト水溶液に浸漬し、８０℃で充分乾燥させた後、８０℃、２５％の水酸化ナトリウム水溶液中に浸漬し、コバルト塩を水酸化コバルトに転換させ、ついで、充分に水洗を行いアルカリ溶液を除去した。こうして比較例２のニッケル正極板ｃを作製した。
【００１７】
《比較例３》
実施例１と同じ多孔度約８５％のニッケル焼結基板を、温度８０℃、ｐＨ１．５で硝酸ニッケル５．５モル／ｌ、硝酸コバルト０．０６モル／ｌおよび硝酸イットリウム０．３モル／ｌを含む水溶液に浸漬し、８０℃の雰囲気下で充分乾燥させた後、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬し、ついで、充分に水洗してアルカリ溶液を除去し、乾燥する一連の活物質充填操作を７回繰り返し、基板の細孔内に水酸化ニッケル、水酸化コバルトおよび水酸化イットリウムの混合物からなる層を形成した。
ついで、温度３０℃、ｐＨ２．５、濃度４．０モル／ｌの硝酸コバルト水溶液に浸漬し、８０℃の温度雰囲気下で充分乾燥させた後、温度８０℃、濃度２５％の水酸化ナトリウム水溶液中に浸漬し、コバルト塩を水酸化コバルトに転換させ、ついで、充分に水洗を行いアルカリ溶液を除去した。こうして比較例３のニッケル正極板ｄを作製した。
【００１８】
以上の各正極板ａ１、ａ２、ｂ、ｃおよびｄと、合金組成がＭｍＮｉ_3.5Ｃｏ_0.7Ｍｎ_0.4Ａｌ_0.3（Ｍｍはミッシュメタルで希土類元素の混合物）である水素吸蔵合金を主構成材料とする負極と、微孔性ポリプロピレンフィルム製のセパレータと、アルカリ電解液とから公称容量１．４Ａｈのアルカリ蓄電池Ａ１、Ａ２、Ｂ、ＣおよびＤを組み立てた。
実施例１、２、および比較例１〜３におけるそれぞれの活物質である水酸化ニケルを充填する操作回数と、得られた極板中の水酸化ニッケルの充填密度との関係を図１に示す。水酸化ニッケルの充填密度は、各正極板に充填された水酸化ニッケルの量の化学分析値から１ｇ当たり２８９ｍＡｈとして計算した容量値から求めた。試料数は３である。それぞれの正極板に充填された水酸化ニッケル量を１００重量部としたときの金属酸化物中の他の内容物量の化学分析値を表１に示す。
【００１９】
【表１】

【００２０】
図１に示したように、比較例３は充填回数の増加に伴う充填密度の増加が最も低い。これは、表１に示したように、添加した水酸化イットリウムの量が多いこと、およびニッケル水酸化物とイットリウム水酸化物とを混合した状態では見かけ比重が低いためと考えられる。このため、比較例３によると、高容量密度の極板を得ることはできない。従って、現在求められているような高容量のアルカリ蓄電池は得られない。
次に、本発明の実施例における正極板ａ１、ａ２および比較例３の正極板ｄをそれぞれ断面にしてＥＰＭＡ（electron probe microanalyser）を用いて観察した。正極板ａ１の模式断面図を図２に、正極板ｄの模式断面図を図３にそれぞれ示す。
これらの図において、１０はニッケル焼結基板の骨格を表す。図２においては、骨格のニッケル金属１０に接して水酸化イットリウムからなる第１層１１が形成され、この層１１を覆うように水酸化ニッケルと水酸化コバルトの混合物からなる第２層１２が形成され、第２層１２を覆うように水酸化コバルトからなる第３層が形成されている。正極板ａ２では、第２層１２が水酸化ニッケルと水酸化コバルトと水酸化亜鉛の混合物からなる他は、正極板ａ１と同じである。図３においては、骨格のニッケル金属２０に接して水酸化ニッケル、水酸化コバルトおよび水酸化イットリウムの混合物からなる層２１が形成され、層２１を覆うように水酸化コバルトからなる層２２が形成されている。
【００２１】
次に、上記の電池Ａ１、Ａ２、Ｂ、ＣおよびＤをそれぞれ２０℃の温度雰囲気下で、１４０ｍＡの電流で１５時間充電し、２８０ｍＡの電流で端子電圧が１．０Ｖに低下するまで放電し、それぞれの電池の放電容量を求めた。続いて、これらの各電池を５０℃の温度雰囲気下で１４０ｍＡの電流で１５時間充電した後、２０℃の温度雰囲気下で３時間放電してから２８０ｍＡの電流で端子電圧が１．０Ｖに低下するまで放電して、放電容量を求めた。その結果を表２に示す。
【００２２】
【表２】

【００２３】
表２から明らかなように、ニッケル焼結基板に活物質水酸化ニッケルを充填するに際してイットリウムやコバルトを添加することにより、５０℃における活物質の利用率が大幅に改善できることがわかる。また、添加材としては、コバルトよりイットリウムの方が効果があり、かつ、イットリウムは、図２に示したように、水酸化ニッケルとは混合せずにニッケル骨格に直接接して形成することにより、少量のイットリウムで高温での活物質利用率を向上することができる。
本発明の実施例１の正極を用いた電池Ａ１と比較例２の正極を用いた電池Ｃとを５０℃の温度雰囲気下で１４０ｍＡの電流で１５時間充電した後、２０℃の温度雰囲気下で３時間放置してから２８０ｍＡの電流で端子電圧が１．０Ｖに至るまで放電したときの放電カーブを図４に示す。
図４から電池Ａ１は、電池Ｃと比較して放電容量が高いことがわかる。これは、電池Ａ１の正極は、電池Ｃの正極よりも水酸化コバルト量が少ないため、水酸化ニッケルの平衡電極電位の低下を抑制できたことによるものと思われる。
【００２４】
次に、電池Ａ１、Ａ２、およびＣを５０℃の温度雰囲気下で１４０ｍＡの電流で１５時間充電した後、２０℃の温度雰囲気下で３時間放置してから２８０ｍＡの電流で端子電圧が１．０Ｖに至るまで放電する一連のサイクルを繰り返したときの放電容量の変化を図５に示す。
充放電サイクル寿命は初期容量に対して６０％の時点で寿命と判断した。図５から明らかなように、各電池の寿命は、電池Ａ１が６００サイクル、電池Ａ２が１０００サイクル、電池Ｃが６００サイクルである。電池Ａ２の寿命が特に優れているのは、その正極中の活物質ニッケル水酸化物が、コバルト水酸化物および亜鉛水酸化物と混合されており、特に亜鉛水酸化物の作用によって、電池を過充電したときの正極板の膨潤を防ぎ、そのためセパレータ中の電解液量が変化せずに充放電サイクル寿命が伸びたものと推測される。
上記の実施例においては、基板の骨格に接する第１層にイットリウム水酸化物を用いたが、これに代えてイッテルビウムまたはルテチウムの水酸化物を用いても同様の効果が得られる。また、イットリウム、イッテルビウムおよびルテチウムの２種または３種の混合物の水酸化物を用いてもよい。
【００２５】
【発明の効果】
以上のように本発明によれば、放電時の作動電圧の低下を抑制するとともに、高温での活物質の利用率の高い、高容量密度のアルカリ蓄電池用焼結式ニッケル正極を提供することができる。
【図面の簡単な説明】
【図１】各種方法による活物質の充填操作回数と得られた正極板の活物質の充填密度との関係を示す図である。
【図２】本発明の実施例におけるニッケル正極板の模式断面図である。
【図３】比較例３のニッケル正極板の模式断面図である。
【図４】実施例１の正極板を用いた電池Ａ１と比較例２の正極板を用いた電池Ｃの放電カーブを示す図である。
【図５】実施例１の正極板を用いた電池Ａ１、実施例２の正極板を用いた電池Ａ２および比較例３の正極板を用いた電池Ｃの充放電サイクルに伴う放電容量の変化を示す図である。
【符号の説明】
１０ニッケル焼結基板の骨格
１１水酸化イットリウムの層
１２水酸化ニッケルと水酸化コバルトの混合物の層
１３水酸化コバルトの層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nickel positive electrode plate used for alkaline storage batteries such as nickel-cadmium storage batteries and nickel-hydrogen storage batteries, and a method for producing the same.
[0002]
[Prior art]
In recent years, alkaline storage batteries are required to be lighter, smaller, and have higher performance as their applications expand. Among them, a nickel positive electrode plate used for an electric vehicle or the like is required to be capable of rapid charge / discharge, to have a high active material utilization rate at a high temperature, and to have a long cycle life.
In general, a sintered nickel electrode having a low internal resistance and excellent cycle characteristics has been used for a positive electrode plate of an alkaline storage battery for rapid charge / discharge. This sintered nickel electrode has been added with cadmium and cobalt in order to improve the active material utilization at high temperatures.
However, in recent years, regulations on the use of cadmium compounds are increasing from the standpoint of environmental conservation. Also, in a nickel-hydrogen storage battery using a negative electrode mainly composed of a hydrogen storage alloy, the cadmium compound added to the positive electrode moves during the charge / discharge cycle and covers the negative electrode surface, which becomes an obstruction factor for the negative electrode in charge / discharge. Is also known.
[0003]
On the other hand, the method of adding a cobalt compound to the positive electrode plate needs to add a large amount of expensive cobalt in order to ensure sufficient characteristics. In addition, there is a problem that the voltage at the time of discharge decreases due to a large amount of added cobalt.
Therefore, as disclosed in JP-A-48-50233, etc., by adding an yttrium compound such as yttrium hydroxide to the nickel positive electrode plate, the utilization rate of the active material at room temperature is not lowered, and the temperature is increased. It has been proposed to improve the active material utilization rate. The positive electrode to which yttrium hydroxide is added, for example, immerses a nickel sintered substrate in an acidic aqueous solution containing nickel salt and yttrium salt, and then dries it in an alkaline aqueous solution to convert the nickel salt and yttrium salt into hydroxide. It can manufacture by repeating the series of processes to make until the amount of active materials becomes a desired quantity.
[0004]
[Problems to be solved by the invention]
However, according to this method, the amount of yttrium is increased, and since nickel hydroxide and yttrium hydroxide are produced in a mixed state, the apparent specific gravity is low, so that a high capacity density electrode plate cannot be obtained. There was a problem.
The present invention uses an appropriate amount of an yttrium compound and a cobalt compound to suppress a decrease in operating voltage at the time of discharge, and has a high utilization rate of an active material at a high temperature, and a sintering type for a high capacity density alkaline storage battery. An object is to provide a nickel positive electrode plate.
[0005]
[Means for Solving the Problems]
The nickel positive electrode plate of the present invention is a positive electrode plate comprising a porous nickel sintered substrate and a metal hydroxide mainly composed of nickel hydroxide filled in the substrate, wherein the hydroxide is yttrium, A first layer made of a hydroxide of at least one element selected from the group consisting of ytterbium and lutetium, which is in contact with the substrate, a mixture of nickel hydroxide and cobalt hydroxide, and covering the first layer It consists of a second layer and a third layer made of cobalt hydroxide and covering the second layer.
Here, the amount of hydroxide of at least one element selected from the group consisting of yttrium, ytterbium and lutetium in the first layer is 1 to 4 parts by weight with respect to 100 parts by weight of nickel hydroxide, the second layer cobalt hydroxide is 1 to 5 parts by weight, the amount of cobalt hydroxide in the third layer is Ru 3-6 parts by der.
Furthermore, the second layer preferably contains zinc hydroxide. The amount of zinc hydroxide in the second layer is preferably 3 to 6 parts by weight with respect to 100 parts by weight of nickel hydroxide.
[0006]
In the present invention, (1) a porous nickel sintered substrate is immersed in an acidic aqueous solution of a salt of at least one element selected from the group consisting of yttrium, ytterbium and lutetium, dried, and then immersed in an alkaline aqueous solution. A first layer comprising a hydroxide of at least one element selected from the group consisting of yttrium, ytterbium and lutetium in the pores of the substrate by performing the operation of converting the salt into a hydroxide at least once. (2) The substrate is immersed in an acidic aqueous solution containing nickel salt and cobalt salt, dried, and then immersed in an alkaline aqueous solution to convert the nickel salt and cobalt salt into nickel hydroxide and cobalt hydroxide, respectively. The nickel hydroxide and cobalt hydroxide on the upper side of the first layer of the substrate by performing at least one operation. And (3) immersing the substrate in an aqueous cobalt salt solution, drying it, and then immersing it in an aqueous alkaline solution to convert the cobalt salt into a cobalt hydroxide. Provided is a method for producing a nickel positive electrode plate, which includes a step of forming a third layer made of cobalt hydroxide on the upper side of the second layer by performing the operation at least once. Here, in the obtained positive electrode plate, the amount of hydroxide in the first layer is 1 to 4 parts by weight and the amount of cobalt hydroxide in the second layer is 1 to 100 parts by weight of nickel hydroxide. The amount of cobalt hydroxide in the third layer is 5 to 6 parts by weight.
[0007]
In the present invention, (1) a porous nickel sintered substrate is immersed in an acidic aqueous solution of a salt of at least one element selected from the group consisting of yttrium, ytterbium and lutetium, dried, and then immersed in an alkaline aqueous solution. A first layer comprising a hydroxide of at least one element selected from the group consisting of yttrium, ytterbium and lutetium in the pores of the substrate by performing the operation of converting the salt into a hydroxide at least once. (2) The substrate is immersed in an acidic aqueous solution containing a nickel salt, a cobalt salt and a zinc salt, dried, and then immersed in an alkaline aqueous solution to convert the nickel salt, cobalt salt and zinc salt into nickel hydroxide, respectively. , By performing the operation of converting to cobalt hydroxide and zinc hydroxide at least once, Forming a second layer comprising a mixture of nickel hydroxide, cobalt hydroxide and zinc hydroxide on the upper side of the substrate, and (3) immersing the substrate in an aqueous cobalt salt solution, drying, and then an alkaline aqueous solution. Manufacturing a nickel positive electrode plate having a step of forming a third layer made of cobalt hydroxide on the upper side of the second layer by performing an operation of converting the cobalt salt into cobalt hydroxide at least once by immersion in Provide law. Here, in the obtained nickel positive electrode plate, the amount of hydroxide in the first layer is 1 to 4 parts by weight and the amount of cobalt hydroxide in the second layer is 1 with respect to 100 parts by weight of nickel hydroxide. -5 parts by weight, the amount of zinc hydroxide in the second layer is 3-6 parts by weight, and the amount of cobalt hydroxide in the third layer is 3-6 parts by weight.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the nickel positive electrode plate according to the present invention has three metal hydroxide layers formed in the pores of the sintered nickel substrate. The first layer is a hydroxide layer that covers the surface of the nickel metal that forms the skeleton of the sintered substrate, and is made of a hydroxide of at least one element selected from the group consisting of yttrium, ytterbium, and lutetium. The second layer is composed of a mixture of nickel hydroxide as an active material and cobalt hydroxide as a conductive agent. The third layer is a cobalt hydroxide layer. Since the surface of the nickel metal forming the skeleton of the sintered substrate is covered with a hydroxide of at least one element selected from the group consisting of yttrium, ytterbium and lutetium, the oxygen generation potential of the electrode is increased. The nickel hydroxide as an active material contained in the second layer is mixed with cobalt hydroxide as a conductive agent to cover the first layer, and the upper side of the second layer is a small amount of highly conductive cobalt hydroxide. It is covered with a third layer of objects. For this reason, the fall of the operating voltage at the time of discharge is suppressed, and the utilization factor of a positive electrode active material is high also at the high temperature of 40 degreeC or more.
[0009]
In the positive electrode plate, the amount of the first layer hydroxide covering the surface of nickel constituting the substrate is 1 to 4 parts by weight with respect to 100 parts by weight of the nickel hydroxide as the active material, and the upper side thereof. The amount of cobalt hydroxide in the mixture of nickel hydroxide and cobalt hydroxide in the second layer covering is 1 to 5 parts by weight, and further the amount of cobalt hydroxide in the third layer covering the upper side thereof. the amount is

Ru

3 to 6 parts by weight of der.
When the amount of hydroxide in the first layer is less than 1 part by weight, the amount of cobalt hydroxide in the second layer is less than 1 part by weight, and the amount of cobalt hydroxide in the third layer is less than 3 parts by weight The effect of adding them does not appear sufficiently. When the amount of hydroxide in the first layer exceeds 4 parts by weight, the amount of cobalt hydroxide in the second layer exceeds 5 parts by weight, and the amount of cobalt hydroxide in the third layer exceeds 6 parts by weight. The amount of nickel hydroxide as the active material is relatively reduced, and the capacity density is unsatisfactory.
When the second layer containing the nickel hydroxide of the active material further contains zinc hydroxide, the positive electrode plate can be prevented from swelling when the battery is overcharged. Thereby, the fluctuation | variation of the electrolyte solution amount in a separator is lose | eliminated, and the charging / discharging cycle life of a battery is extended.
[0010]
【Example】
Examples of the present invention will be described below.
[0011]
Example 1
A nickel sintered substrate having a porosity of about 85% sintered in a reducing atmosphere was prepared. This substrate is immersed in an aqueous yttrium nitrate solution at a temperature of 30 ° C., pH 2.5, and a concentration of 0.3 mol / l, and is sufficiently dried in a temperature atmosphere of 80 ° C. to retain the yttrium salt in the pores of the substrate. I let you. Next, the substrate is immersed in a 25% aqueous solution of sodium hydroxide at a temperature of 80 ° C. to convert the yttrium salt into yttrium hydroxide, and then washed thoroughly with water to remove the alkaline solution. It was fully dried in the temperature atmosphere. Thus, an yttrium hydroxide layer was formed in the pores of the nickel sintered substrate.
Next, this substrate was immersed in an aqueous solution containing 5.5 mol / l nickel nitrate and 0.06 mol / l cobalt nitrate at a temperature of 80 ° C. and a pH of 1.5, and sufficiently dried at a temperature of 80 ° C. A mixture of nickel and cobalt salts was retained in the pores of the substrate. Next, the substrate is immersed in an aqueous solution of sodium hydroxide having a temperature of 80 ° C. and a concentration of 25% to convert the nickel salt and cobalt salt into nickel hydroxide and cobalt hydroxide, respectively, and then washed thoroughly with water. Then, a series of active material filling operations of removing the alkaline solution and drying was repeated 7 times. Thus, a layer of a mixture of nickel hydroxide and cobalt hydroxide was formed on the upper side of the yttrium hydroxide layer covering the substrate.
[0012]
Furthermore, the substrate is immersed in an aqueous cobalt nitrate solution at a temperature of 30 ° C., pH 2.5, and a concentration of 4.0 mol / l, and is sufficiently dried in an atmosphere at 80 ° C. to hold the cobalt salt in the pores of the substrate. I let you. Next, the cobalt salt was converted into cobalt hydroxide by immersing it in a sodium hydroxide aqueous solution at a temperature of 80 ° C. and a concentration of 25%, and then washed thoroughly with water to remove the alkaline solution. A cobalt hydroxide layer was thus formed on the nickel hydroxide and cobalt hydroxide mixture layer.
A nickel positive electrode plate was obtained as described above. This is a1.
[0013]
Example 2
A nickel sintered substrate having a porosity of about 85% as in Example 1 is immersed in an aqueous yttrium nitrate solution having a temperature of 30 ° C., a pH of 2.5, and a concentration of 0.3 mol / l, and is sufficiently dried in an atmosphere of 80 ° C. After that, it is immersed in a 25% aqueous sodium hydroxide solution at a temperature of 80 ° C. to convert the yttrium salt into yttrium hydroxide, and then thoroughly washed with water to remove the alkaline solution, and it is sufficient in a temperature atmosphere of 80 ° C. After drying, an yttrium hydroxide layer was formed in the pores of the nickel sintered substrate.
The substrate was then immersed in an aqueous solution containing nickel nitrate 5.5 mol / l, cobalt nitrate 0.06 mol / l and zinc nitrate 0.08 mol / l at a temperature of 80 ° C. and a pH of 1.5. After sufficiently drying at a temperature, it is immersed in an aqueous sodium hydroxide solution at a temperature of 80 ° C. and a concentration of 25% to convert nickel salt, cobalt salt and zinc salt to nickel hydroxide, cobalt hydroxide and zinc hydroxide, respectively. Next, a series of active material filling operations of thoroughly washing with water to remove the alkaline solution and drying are repeated seven times, and a layer of a mixture of nickel hydroxide, cobalt hydroxide and zinc hydroxide is placed above the yttrium hydroxide layer. Formed.
[0014]
Further, this electrode plate was immersed in an aqueous cobalt nitrate solution at 30 ° C., pH 2.5, and a concentration of 4.0 mol / l and sufficiently dried in a temperature atmosphere of 80 ° C., and then at a temperature of 80 ° C. and a concentration of 25%. It was immersed in an aqueous sodium hydroxide solution to convert the cobalt salt to cobalt hydroxide, and then washed thoroughly with water to remove the alkaline solution. Thus, a nickel positive electrode plate a2 of this example was produced.
[0015]
<< Comparative Example 1 >>
A nickel sintered substrate having a porosity of about 85% as in Example 1 was immersed in an aqueous solution containing 5.5 mol / l nickel nitrate and 0.06 mol / l cobalt nitrate at a temperature of 80 ° C. and a pH of 1.5. After sufficiently drying in a temperature atmosphere of ℃, immersed in an aqueous solution of sodium hydroxide having a temperature of 80 ℃ and a concentration of 25% to convert nickel salt and cobalt salt to nickel hydroxide and cobalt hydroxide, respectively, A series of operations for filling the active material was repeated 7 times by washing with water, removing the alkaline solution, and drying. Thus, a layer made of a mixture of nickel hydroxide and cobalt hydroxide was formed in the pores of the substrate.
Next, this electrode plate was immersed in an aqueous cobalt nitrate solution having a temperature of 30 ° C., pH 2.5, and a concentration of 4.0 mol / l, and sufficiently dried in a temperature atmosphere of 80 ° C. After that, the temperature was 80 ° C. and the concentration was 25%. Was immersed in an aqueous solution of sodium hydroxide to convert the cobalt salt to cobalt hydroxide, and then washed thoroughly with water to remove the alkaline solution. The nickel positive electrode plate of Comparative Example 1 thus obtained is designated b.
[0016]
<< Comparative Example 2 >>
A nickel sintered substrate having a porosity of about 85% as in Example 1 was immersed in an aqueous cobalt nitrate solution having a temperature of 30 ° C., a pH of 2.5, and a concentration of 1 mol / l, and was sufficiently dried in an atmosphere of 80 ° C. And immersed in an aqueous solution of sodium hydroxide at a temperature of 80 ° C. and 25% to convert the cobalt salt into cobalt hydroxide, sufficiently washed with water to remove the alkaline solution, and hydroxylated into the pores of the nickel sintered substrate. A cobalt layer was formed.
This substrate was immersed in an aqueous solution containing 5.5 mol / l nickel nitrate and 0.06 mol / l cobalt nitrate at a temperature of 80 ° C. and a pH of 1.5, and after sufficiently drying at 80 ° C., 80 ° C. and 25% A series of active material filling operations in which the nickel salt and cobalt salt are converted to nickel hydroxide and cobalt hydroxide, respectively, and then washed thoroughly with water to remove the alkaline solution and dry. Repeated 7 times to form a layer consisting of a mixture of nickel hydroxide and cobalt hydroxide.
Next, this electrode plate was immersed in a cobalt nitrate aqueous solution having a temperature of 30 ° C., pH 2.5, and a concentration of 4.0 mol / l, sufficiently dried at 80 ° C., and then 80 ° C., 25% sodium hydroxide aqueous solution. It was dipped in to convert the cobalt salt into cobalt hydroxide, and then washed thoroughly with water to remove the alkaline solution. Thus, a nickel positive electrode plate c of Comparative Example 2 was produced.
[0017]
<< Comparative Example 3 >>
A nickel sintered substrate having a porosity of about 85%, which is the same as that of Example 1, was obtained at a temperature of 80 ° C. and a pH of 1.5. Nickel nitrate 5.5 mol / l, cobalt nitrate 0.06 mol / l and yttrium nitrate 0.3 mol / l I was immersed in an aqueous solution containing 1 and sufficiently dried in an atmosphere of 80 ° C., then immersed in an aqueous solution of sodium hydroxide having a temperature of 80 ° C. and a concentration of 25%, and then thoroughly washed with water to remove the alkaline solution, A series of drying operations for filling the active material was repeated 7 times to form a layer made of a mixture of nickel hydroxide, cobalt hydroxide and yttrium hydroxide in the pores of the substrate.
Then, after immersing in a cobalt nitrate aqueous solution having a temperature of 30 ° C., pH 2.5, and a concentration of 4.0 mol / l, and sufficiently drying in a temperature atmosphere of 80 ° C., a sodium hydroxide aqueous solution having a temperature of 80 ° C. and a concentration of 25%. It was dipped in to convert the cobalt salt into cobalt hydroxide, and then washed thoroughly with water to remove the alkaline solution. Thus, a nickel positive electrode plate d of Comparative Example 3 was produced.
[0018]
A negative electrode mainly composed of the above-described positive electrode plates a1, a2, b, c and d and a hydrogen storage alloy having an alloy composition of MmNi _3.5 Co _0.7 Mn _0.4 Al _0.3 (Mm is a mixture of rare earth elements and misch metal). Then, alkaline storage batteries A1, A2, B, C and D having a nominal capacity of 1.4 Ah were assembled from a separator made of a microporous polypropylene film and an alkaline electrolyte.
FIG. 1 shows the relationship between the number of operations for filling nickel hydroxide, which is each active material in Examples 1 and 2 and Comparative Examples 1 to 3, and the packing density of nickel hydroxide in the obtained electrode plate. . The packing density of nickel hydroxide was determined from the capacity value calculated as 289 mAh per gram from the chemical analysis value of the amount of nickel hydroxide packed in each positive electrode plate. The number of samples is 3. Table 1 shows the chemical analysis values of the other contents in the metal oxide when the amount of nickel hydroxide charged in each positive electrode plate is 100 parts by weight.
[0019]
[Table 1]

[0020]
As shown in FIG. 1, the comparative example 3 has the lowest increase in filling density with the increase in the number of fillings. This is presumably because, as shown in Table 1, the amount of added yttrium hydroxide is large, and the apparent specific gravity is low when nickel hydroxide and yttrium hydroxide are mixed. For this reason, according to Comparative Example 3, a high capacity density electrode plate cannot be obtained. Therefore, a high capacity alkaline storage battery as currently required cannot be obtained.
Next, the positive electrode plates a1 and a2 in the example of the present invention and the positive electrode plate d of Comparative Example 3 were observed in cross section using an EPMA (electron probe microanalyser). A schematic cross-sectional view of the positive electrode plate a1 is shown in FIG. 2, and a schematic cross-sectional view of the positive electrode plate d is shown in FIG.
In these figures, 10 represents the skeleton of the nickel sintered substrate. In FIG. 2, a first layer 11 made of yttrium hydroxide is formed in contact with the skeleton nickel metal 10, and a second layer 12 made of a mixture of nickel hydroxide and cobalt hydroxide is formed so as to cover this layer 11. Then, a third layer made of cobalt hydroxide is formed so as to cover the second layer 12. The positive electrode plate a2 is the same as the positive electrode plate a1 except that the second layer 12 is made of a mixture of nickel hydroxide, cobalt hydroxide, and zinc hydroxide. In FIG. 3, a layer 21 made of a mixture of nickel hydroxide, cobalt hydroxide and yttrium hydroxide is formed in contact with the nickel metal 20 of the skeleton, and a layer 22 made of cobalt hydroxide is formed so as to cover the layer 21. ing.
[0021]
Next, the batteries A1, A2, B, C and D are each charged at a current of 140 mA for 15 hours under a temperature atmosphere of 20 ° C., and discharged until the terminal voltage is reduced to 1.0 V at a current of 280 mA. The discharge capacity of each battery was determined. Subsequently, these batteries were charged for 15 hours at a current of 140 mA under a temperature atmosphere of 50 ° C., then discharged for 3 hours under a temperature atmosphere of 20 ° C., and then the terminal voltage decreased to 1.0 V at a current of 280 mA. The battery was discharged until the discharge capacity was determined. The results are shown in Table 2.
[0022]
[Table 2]

[0023]
As is apparent from Table 2, it can be seen that the utilization rate of the active material at 50 ° C. can be greatly improved by adding yttrium or cobalt when the nickel sintered substrate is filled with the active material nickel hydroxide. Further, as an additive, yttrium is more effective than cobalt, and yttrium is formed in direct contact with the nickel skeleton without being mixed with nickel hydroxide, as shown in FIG. With a small amount of yttrium, the active material utilization at high temperatures can be improved.
The battery A1 using the positive electrode of Example 1 of the present invention and the battery C using the positive electrode of Comparative Example 2 were charged at a current of 140 mA for 15 hours in a temperature atmosphere of 50 ° C., and then in a temperature atmosphere of 20 ° C. FIG. 4 shows a discharge curve when the terminal voltage reaches 1.0 V at a current of 280 mA after being left for 3 hours.
4 that the battery A1 has a higher discharge capacity than the battery C. FIG. This is probably because the positive electrode of the battery A1 has a smaller amount of cobalt hydroxide than the positive electrode of the battery C, and thus the decrease in the equilibrium electrode potential of nickel hydroxide can be suppressed.
[0024]
Next, the batteries A1, A2 and C were charged for 15 hours at a current of 140 mA in a temperature atmosphere of 50 ° C., then left for 3 hours in a temperature atmosphere of 20 ° C., and then the terminal voltage was 1. FIG. 5 shows a change in discharge capacity when a series of cycles for discharging to 0 V is repeated.
The charge / discharge cycle life was judged as life at 60% of the initial capacity. As is clear from FIG. 5, the battery life is 600 cycles for battery A1, 1000 cycles for battery A2, and 600 cycles for battery C. The life of the battery A2 is particularly excellent because the active material nickel hydroxide in the positive electrode is mixed with cobalt hydroxide and zinc hydroxide. It is presumed that the positive electrode plate is prevented from swelling when overcharged, and therefore the charge / discharge cycle life is extended without changing the amount of the electrolyte in the separator.
In the above embodiment, yttrium hydroxide is used for the first layer in contact with the skeleton of the substrate, but the same effect can be obtained by using ytterbium or lutetium hydroxide instead. Alternatively, a hydroxide of a mixture of two or three of yttrium, ytterbium and lutetium may be used.
[0025]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a sintered nickel positive electrode for an alkaline storage battery having a high capacity density and a high utilization factor of an active material at a high temperature while suppressing a decrease in operating voltage during discharge. it can.
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between the number of active material filling operations performed by various methods and the active material filling density of the obtained positive electrode plate.
FIG. 2 is a schematic cross-sectional view of a nickel positive electrode plate in an example of the present invention.
3 is a schematic cross-sectional view of a nickel positive electrode plate of Comparative Example 3. FIG.
4 is a diagram showing discharge curves of a battery A1 using the positive electrode plate of Example 1 and a battery C using the positive electrode plate of Comparative Example 2. FIG.
5 shows changes in discharge capacity with charge / discharge cycles of a battery A1 using the positive electrode plate of Example 1, a battery A2 using the positive electrode plate of Example 2, and a battery C using the positive electrode plate of Comparative Example 3. FIG. FIG.
[Explanation of symbols]
10 Nickel sintered substrate skeleton 11 Yttrium hydroxide layer 12 Nickel hydroxide and cobalt hydroxide mixture layer 13 Cobalt hydroxide layer

Claims

A porous nickel sintered substrate, and a positive electrode plate made of a metal hydroxide mainly composed of nickel hydroxide filled in the substrate, wherein the hydroxide is selected from the group consisting of yttrium, ytterbium and lutetium A first layer made of a hydroxide of at least one element in contact with the substrate, a second layer made of a mixture of nickel hydroxide and cobalt hydroxide and covering the first layer, and cobalt hydroxide It consists of a third layer covering the second layer, and the amount of hydroxide in the first layer is 1 to 4 parts by weight with respect to 100 parts by weight of nickel hydroxide, and the cobalt hydroxide in the second layer 1 to 5 parts by weight, and the amount of the third layer of cobalt hydroxide is 3 to 6 parts by weight.

The nickel positive electrode plate according to claim 1, wherein the second layer further contains zinc hydroxide.

The nickel positive electrode plate according to claim 2, wherein the amount of zinc hydroxide in the second layer is 3 to 6 parts by weight with respect to 100 parts by weight of nickel hydroxide.

The multi-porous sintered nickel substrate was immersed yttrium, an acidic aqueous solution of a salt of at least one element selected from the group consisting of ytterbium and lutetium, dried and then the hydroxide the salt is immersed in an aqueous alkaline solution A step of forming a first layer made of a hydroxide of at least one element selected from the group consisting of yttrium, ytterbium and lutetium in the pores of the substrate by performing the operation of converting to at least once, By immersing the substrate in an acidic aqueous solution containing nickel salt and cobalt salt, drying, and then immersing in an alkaline aqueous solution to convert the nickel salt and cobalt salt to nickel hydroxide and cobalt hydroxide, respectively, at least once. And a mixture of nickel hydroxide and cobalt hydroxide on the first layer of the substrate. A step of forming two layers, and immersing the substrate in an aqueous cobalt salt solution, drying, then immersing in an alkaline aqueous solution, and converting the cobalt salt to cobalt hydroxide at least once; A step of forming a third layer made of cobalt hydroxide on the upper side of the two layers, with respect to 100 parts by weight of nickel hydroxide, the amount of hydroxide of the first layer is 1 to 4 parts by weight; The manufacturing method of the nickel positive electrode plate whose quantity of the cobalt hydroxide of a 2 layer is 1-5 weight part, and the quantity of the cobalt hydroxide of a 3rd layer is 3-6 weight part.

The multi-porous sintered nickel substrate was immersed yttrium, an acidic aqueous solution of a salt of at least one element selected from the group consisting of ytterbium and lutetium, dried and then the hydroxide the salt is immersed in an aqueous alkaline solution A step of forming a first layer made of a hydroxide of at least one element selected from the group consisting of yttrium, ytterbium and lutetium in the pores of the substrate by performing the operation of converting to at least once, The substrate is immersed in an acidic aqueous solution containing nickel salt, cobalt salt and zinc salt, dried and then immersed in an alkaline aqueous solution to convert the nickel salt, cobalt salt and zinc salt into nickel hydroxide, cobalt hydroxide and zinc hydroxide, respectively. By performing the converting operation at least once, nickel hydroxide is formed on the upper side of the first layer of the substrate. Forming a second layer composed of a mixture of the product, cobalt hydroxide and zinc hydroxide, and immersing the substrate in an aqueous cobalt salt solution, drying, then immersing in an alkaline aqueous solution, A step of forming a third layer made of cobalt hydroxide on the upper side of the second layer by performing the operation of converting to a hydroxide at least once, and with respect to 100 parts by weight of nickel hydroxide, The amount of hydroxide in one layer is 1 to 4 parts by weight, the amount of cobalt hydroxide in the second layer is 1 to 5 parts by weight, the amount of zinc hydroxide in the second layer is 3 to 6 parts by weight, The manufacturing method of the nickel positive electrode plate whose quantity of 3 layers of cobalt hydroxide is 3-6 weight part.