【０００１】
【発明の属する技術分野】
本発明は、鉛蓄電池に関するものである。
【０００２】
【従来の技術】
鉛蓄電池は、二次電池（蓄電池）の中でも特に低温特性に優れ、電池特性とコスト面でバランスのとれた二次電池である。鉛蓄電池は単位体積当たりの重量がリチウム二次電池等に比べて重く、エネルギー密度の点で基本的な問題点があった。その原因は、重い鉛電極を使用する点、および比重の重い硫酸を電解液に使用する点にある。
【０００３】
しかし、鉛電極を極力薄くして、単位重量あたりの電極面積を広くし、リテーナ（隔膜）を挟んで負極板と正極板を巻き取るようにして構成した捲回式鉛蓄電池は、高エネルギー密度が期待できる。電極を薄くし薄膜状にして捲回すれば、軽量で大面積の電極を有する電池に構成できるため、高エネルギー密度を得ることができる。
【０００４】
例えば、捲回式鉛蓄電池を構成するために、薄い電極を損傷なく巻き取る工夫の鉛蓄電池が提案されている（例えば、特許文献１参照。）。
【０００５】
また、捲回式のシール鉛蓄電池に関する詳細を開示したものもある（例えば、非特許文献１参照。）。
【０００６】
さらに、鉛電極上にＢａＰｂＯ３ （メタ鉛酸バリウム）皮膜を生成させ、鉛電極の耐食性を向上させる方法も提案されている（例えば、特許文献２参照。）。
【０００７】
【特許文献１】
特開平６−２０３８７０号公報
【０００８】
【非特許文献１】
ジーエス ニュース テクニカル リポート（ＧＳ Ｎｅｗｓ Ｔｅｃｈｎｉｃａｌ Ｒｅｐｏｒｔ）、第２号、第５８巻、１９９９年１２月、「円筒形高出力シール鉛電池の開発」
【０００９】
【特許文献２】
特開平７−２７２７２７号公報
【００１０】
【発明が解決しようとする課題】
捲回式鉛蓄電池は電極厚さを薄くできれば薄いほど同一重量に対して表面積が増えるため、エネルギー密度が高くなる。しかし、硫酸中で機能を有する鉛蓄電池反応は、鉛電極の腐食による劣化が同時進行する電池でもあり、鉛電極の薄膜化は同時に電極の腐食，破断等による電池機能劣化および機能停止のリスクを伴う基本的な技術課題を伴う。
【００１１】
特に、捲回式鉛蓄電池では正極板の腐食速度が大きいため、電極の薄膜化で問題になるのは正極板側が中心となる。薄膜化により腐食現象は正極板の破断等を誘起し、突然の電池機能停止等が現れるため、捲回式鉛蓄電池に必要な電極の薄膜化に伴う腐食現象による電池機能劣化および停止を抑制するための技術が必要である。
【００１２】
本発明の目的は、正極板の構造によって耐食性を向上させることができる鉛蓄電池を提供することにある。
【００１３】
【課題を解決するための手段】
鉛蓄電池で、電極の薄膜化上重要となる鉛正極板の耐食性を向上させる方法には、正極板の耐食性そのものを向上させるのが直接的であるが、正極板の構造によって耐食性を向上させ、正極板の長寿命化、高信頼化を図ることが可能である。
【００１４】
即ち、本発明は、正極板と負極板の間に、電解液を含有するリテーナが介在されて積層されて電池容器に収容された鉛蓄電池において、正極板は、正極活物質層を有する正極活物質集電体と、正極活物質層を有しない正極集電体と、両者の間に介在された正極集電体保護層とが積層され、正極活物質集電体と正極集電体とが電気的に接続されて構成され、正極活物質層を有しない正極集電体は負極板に対向せず、正極活物質層を有する正極活物質集電体は負極板に対向する構造になっていることを特徴とする。
【００１５】
このような構成の鉛蓄電池によれば、負極板に対向する正極活物質集電体に腐食による破断、破断による正極板のアイランド状（島状）の分散破断状態が発生する。このような状態になっても、負極板に対向しない正極集電体には、腐食による破断、破断による正極板のアイランド状（島状）の分散破断状態は発生しない。このため正極活物質集電体の破断によっても、電池反応の電子は正極集電体を通じて負極板と電気的コンタクトを保つことができる。それゆえ本発明によれば、正極板の構造によって耐食性を向上させることができる。また、正極集電体と正極活物質集電体との間に介在された正極集電体保護層が、正極集電体の溶出を抑制する役割を担い、また島状に分散破断した正極活物質集電体を有効活用する担い手となる。
【００１６】
本発明において正極集電体は、正極活物質集電体よりも高い信頼性が必要になる。このため本発明では、正極集電体は正極活物質集電体と同等以上の耐腐食性を有するものであることが好ましい。
【００１７】
また本発明の鉛蓄電池において、正極活物質層を有する正極活物質集電体は、正極集電体保護層を介して正極活物質層を有しない正極集電体の両面に配置されていることが好ましい。このような構成になっていると、正極板の両面に負極板を配置することができる。このため捲回式鉛蓄電池に本発明を適用することができる。
【００１８】
また本発明の鉛蓄電池において、正極集電体保護層は、電気絶縁性を有する材料からなるものであっても、電子伝導性を有する材料からなるものであっても、いずれでもよい。
【００１９】
また、正極集電体保護層は、電気絶縁性を有する材料または電子伝導性を有する材料に電子導電性物質を付与させたものであってもよい。この電子導電性物質としては、鉛酸化物（ＰｂＯ ２−ｘ ）、酸化第二スズ（ＳｎＯ２ ）、メタ鉛酸バリウム（ＢａＰｂＯ３ ）から選択される１種以上を用いることができる。
【００２０】
電気絶縁性を有する材料は、水および電解液中の電解質イオンを透過するものでも、水および電解液中の電解質イオンを透過しないものでも、いずれでもよい。
【００２１】
電子伝導性を有する材料は、水および電解液中の電解質イオンを透過するものでも、水および電解液中の電解質イオンを透過しないものでも、いずれでもよい。
【００２２】
さらに本発明の鉛蓄電池においては、正極板と負極板とこれら両極の間に介在させた電解液を含有するリテーナとが、捲回されて積層されていることが好ましい。このようになっていると、捲回式鉛蓄電池を構成することができる。この場合、正極板は、正極活物質層を有する正極活物質集電体を、正極集電体保護層を介して正極活物質層を有しない正極集電体の両面に配置し、正極活物質集電体と正極集電体とを電気的に接続した構成にすることが好ましい。構造的には、正極集電体はあえて鉛である必要はないが、正極板、負極板の酸素および水素発生に関する電気化学的な過電圧特性を悪くする材料は避けなければならない。このため正極集電体を構成する最も容易な材料は、正極活物質集電体と同じ組成の鉛である。
【００２３】
極限まで薄膜化された捲回式の正極活物質集電体の腐食による破断、破断による正極板のアイランド状（島状）の分散破断状態において、正極活物質層を有する正極活物質集電体を、正極集電体保護層を介して正極活物質層を有しない正極集電体の両面に配置し、正極活物質集電体と正極集電体とを電気的に接続した構成は、正極活物質集電体が破断状態、島状に分散破断した正極板を有効に機能させることが可能である。即ち、捲回式の正極活物質集電体の間にある正極集電体によって、正極活物質層を有する正極活物質集電体が破断しても、電池反応の電子は正極集電体を通じて負極板と電気的コンタクトを保つことができる。この正極集電体は、この意味において正極活物質層を有する正極活物質集電体よりも高信頼性が必要になる。正極集電体の両面に圧着された正極集電体保護層が正極集電体の溶出を抑制する役割を担い、また島状に分散破断した正極活物質集電体を有効活用する担い手となる。正極集電体の耐食性を高めるためには、電解質である硫酸と正極集電体を直接接触させないことが重要である。島状に分散破断した正極活物質集電体を有効活用するには、正極集電体保護層として電子導電性を有する材質を使えばよい。正極集電体保護層自身が電子伝導性がない場合においても、たとえば合成繊維にＰｂＯ２ 等の電子導電性物質を塗布すれば同様な機能を有することになる。正極集電体の高耐食化を目指す場合、正極集電体保護層としては高い対硫酸遮蔽性に優れた材質のものを選べば良い。従って、薄膜化する必要がある捲回式鉛蓄電池の正極活物質集電体の破断等による機能劣化、短寿命現象は、正極活物質層を有する正極活物質集電体２枚の中間に集電機能を有する正極集電体と、この正極集電体を保護する機能を併せ持つ正極集電体保護層を組み合わせることにより抑制することができる。この場合の負極板に接する正極板構成は、捲回式鉛蓄電池の場合、負極活物質集電体／負極活物質／リテーナ／正極活物質／正極活物質集電体／正極集電体保護層／正極集電体／正極集電体保護層／正極活物質集電体／正極活物質／リテーナ／負極活物質／負極活物質集電体の構成になる。リテーナは硫酸液を含む隔膜であり、正極板と負極板の電気的なショートを抑制するとともに、反応活物質のひとつであるプロトンを含む硫酸を含浸させる機能を有する。
【００２４】
【発明の実施の形態】
以下、本発明の実施の形態について説明する。
【００２５】
（実施の形態１）
図１（Ａ）（Ｂ）は本発明に係る鉛蓄電池を捲回式鉛蓄電池に適用した実施の形態１の電池外観と内部電極構造を示す斜視図である。この捲回式鉛蓄電池において、図１（Ａ）は樹脂製の電池容器（電槽）１の上下に正極端子２、負極端子３がついた外観構造図である。電池内部の電極構造は、図（Ｂ）に示すように、負極板４と正極板５が、硫酸等の電解液を含むリテーナ６を間に挟んで捲回したものである。リテーナ６は、電池反応に必要な電解液を含む機能と、負極板４と正極板５の静電的オーミックコンタクトを断ち、電気的なショートを防ぐためのセパレータとしての役割を担う。内部正極取出し部７は正極端子２に接続され、内部負極取出し部８は負極板３に接続されている。
【００２６】
図２は、本発明を適用した実施の形態１の捲回式鉛蓄電池の詳細な電池内部電極構造を示す断面図である。中央部の正極板５は、薄い鉛板の３重構造である。即ち、この正極板５は、中間に位置する鉛製の正極集電体９の左右両側にシート状の正極集電体保護層１１を介して鉛製の正極活物質集電体１０が配置され、正極集電体９と左右の正極活物質集電体１０とは接続部材１２により電気的に接続された構造になっている。中間に位置する正極集電体９は、正極板５と負極板４の間で出入りする電池反応に伴う電子の移動をバックアップする役割を中心に担っている。正極集電体保護層１１は、正極集電体９が電池正極反応で腐食溶出する挙動を抑制する機能を有する。各正極活物質集電体１０の両面には、正極活物質層１３が圧着塗布されている。これら正極活物質層１３が塗布された正極活物質集電体１０の外側には、リテーナ６を介して負極活物質集電体１４がそれぞれ配置されている。各負極活物質集電体１４には、負極活物質１５が圧着塗布されている。これら負極活物質集電体１４と負極活物質１５とにより負極板４が構成されている。これら正極板５とリテーナ６と負極板４は、全体的に渦巻き状に捲回されている。捲回式正極板５は、できるだけ薄い正極集電体９と正極活物質集電体１０とを使用するのが好ましい。
【００２７】
このような鉛蓄電池では、正極活物質層を有しない正極集電体９は負極板４に対向せず、正極活物質層１３を有する正極活物質集電体１０は負極板４に対向する構造になっている。
【００２８】
図３は、実施の形態１の正極板５の溶出、腐食現象による電池機能上の信頼性低下を回復し、高信頼性を有する鉛蓄電池構造に関する本発明の評価内容を示す評価フロー図である。この評価フロー図の中で、正極集電体保護層１１で挟んで正極集電体９を設ける構造および正極集電体保護層１１の材質が、正極板５の耐食性及び正極板５の有効活用上の鍵を握る。
【００２９】
正極集電体保護層１１の材質は、大きく２つの内容に大別される。その１つは、正極集電体保護層１１の材質が電池反応の電子のやり取りに必要な電気伝導性（イオン導電性を含む）を有するか否かであり、他の１つは、正極集電体保護層１１が水、電解質等を通す材質か否かである。水、電解質等を通す材質としては、最も単純な構造としては多孔質材である。正極集電体保護層１１は、正極活物質層１３が塗布された正極活物質集電体１０が破断、あるいは島状に孤立分散してもそれらが有効活用できること、しかも正極集電体９の溶出を防げる機能が必要である。この点で最も優れた正極集電体保護層１１の材質は、自分自身に電子伝導性があり、酸素発生過電圧特性に優れ、下地の正極集電体９の腐食を抑制できる、即ち鉛イオンの通過ができない、水不透過性の膜特性が良い（図３中では、◎で表示）材質である。正極集電体保護層１１の材質に電子伝導性があることは、正極活物質集電体１０の溶出により島状に分散した鉛上での電池反応により生じる電子の移動を可能にする。これにより正極板５、負極板４間での電池反応により生じた電子の移動が可能になり、充電機能等も有効に活用できる。正極集電体保護層１１の材質に電子伝導性がない場合、いわゆる電気絶縁材の場合は島状に腐食して取り残された部分の電池反応への活用はできない。しかし、下地の正極集電体９の溶出に関する保護膜としての役割は残り、正極活物質層１３が塗布された正極活物質集電体１０が上下に破断された場合においても、正極集電体９が集電部としての役割を担い、電池の高耐久性、高信頼化ができる。
【００３０】
図３の低Ｒ（ただし、Ｒは電気抵抗）材は、基本的に電池電圧特性、酸素過電圧、溶出した場合の負極板析出による水素過電圧特性への悪影響等が最小限に抑えられる素材であり、かつ硫酸中で信頼性があるものである。高Ｒ材は、基本的に通常の耐硫酸性化学繊維、樹脂膜等が該当する。図３で示す、◎、〇、△は正極集電体保護層１１の材質評価上の定性的な評価結果を示す。二重丸◎が最も本発明の目的を活用できるものであり、順次○、△となる。
【００３１】
正極集電体保護層１１は破線で囲んだ低Ｒの材料と高Ｒの材料に大別され、高Ｒの材料が得やすい。高Ｒ材で水が通過できない材料の場合は、アイランド状に取り残された鉛（Ｐｂ）の活用は基本的に困難となるが、正極集電体９の保護機能は維持される。正極集電体保護層１１自身が高Ｒで水が通過できる、いわゆる電解質イオン等が通過できる場合、同様にアイランド状に取り残された鉛（Ｐｂ）の活用は基本的に困難である。しかし、この場合は電池自身の活物質等の介在によって、高Ｒで水不透過の材質に比べればアイランド状に取り残された鉛（Ｐｂ）の活用はより有利となり、導電性物質を混入させることによってアイランド状に取り残された鉛（Ｐｂ）の活用はより一層活用できる構造にできる。しかし、高Ｒで水が通過できる正極集電体保護層１１の場合は、基本的には正極集電体９の鉛イオンが溶液中に解け出ることが可能である。このため水不透過の正極集電体保護層１１の材質に比べ、正極集電体９の腐食速度は高くなる傾向を有する。
【００３２】
（実施の形態２）
図４は、正極集電体９の周りに高電気抵抗の正極集電体保護層１１ａを組み合わせた実施の形態２の正極板５の展開構造を示す斜視図である。高電気抵抗の正極集電体保護層１１ａは通常の樹脂系の素材で形成され、例えば、ポリプロピレン樹脂等がこれに相当する。正極集電体９は、正極活物質集電体１０に鉛製の接続部材１２で接続されている。接続部材１２には、内部正極取出し部７が接続されている。この場合は、１箇所の内部正極取出し部７であるが、上下２箇所からの内部正極取出し部７を設けた構造も機能上有効である。
【００３３】
このような正極板５をもつ鉛蓄電池も、正極活物質層を有しない正極集電体９は負極板４に対向せず、正極活物質層１３を有する正極活物質集電体１０は負極板４に対向する構造にする。
【００３４】
（実施の形態３）
図５は、正極集電体９の周りに水は通過するがそれ自身は電気絶縁性の化学ポリエチレン製の繊維シートでできており、繊維の隙間に導電性物質であるＢａＰｂＯ３ を充填したＢａＰｂＯ３ 充填正極集電体保護層１１ｂを組み合わせた実施の形態３の正極板５の展開構造を示す斜視図である。ＢａＰｂＯ３ の他、ＰｂＯ２ 、ＳｎＯ２ 等それ自身あるいは、それ自身の溶出成分に負極板４での水素過電圧、正極板５での酸素過電圧特性に電池設計、機能上悪い影響を与えない導電性物質が適用できる。水や電解質が繊維製の正極集電体保護層の隙間から浸透してゆくタイプと違い、基本的に水を通過させないポリプロピレン樹脂を使用した場合は、樹脂表面にＢａＰｂＯ３ を圧着塗布する構造となる。
【００３５】
このような正極板５をもつ鉛蓄電池も、正極活物質層を有しない正極集電体９は負極板４に対向せず、正極活物質層１３を有する正極活物質集電体１０は負極板４に対向する構造にする。
【００３６】
上記各例では、本発明を捲回式の鉛蓄電池に適用した場合について説明したが、本発明はこれに限定されるものではなく、平面の負極板４と平面の正極板５とがリテーナ６を介して積層される鉛蓄電池にも同様に適用できるものである。この場合も、正極板５は上記のような構成とし、正極活物質層を有しない正極集電体９は負極板４に対向せず、正極活物質層１３を有する正極活物質集電体１０は負極板４に対向するように構成する。
【００３７】
【発明の効果】
本発明に係る鉛蓄電池では、正極板を、正極活物質層を有する正極活物質集電体と、正極活物質層を有しない正極集電体と、両者の間に介在された正極集電体保護層とを積層し、正極活物質集電体と正極集電体とを電気的に接続して構成し、正極活物質層を有しない正極集電体は負極板に対向せず、正極活物質層を有する正極活物質集電体は負極板に対向するようにしたので、負極板に対向する正極活物質集電体は腐食による破断、破断による正極板のアイランド状（島状）の分散破断状態が発生するが、負極板に対向しない正極集電体は腐食による破断、破断による正極板のアイランド状（島状）の分散破断状態は発生しない。このため正極活物質集電体の破断によっても、電池反応の電子は正極集電体を通じて負極板と電気的コンタクトを保つことができる。それゆえ本発明によれば、正極板の構造によって耐食性を向上させることができる。また、正極集電体と正極活物質集電体との間に介在された正極集電体保護層が、正極集電体の溶出を抑制する役割を担い、また島状に分散破断した正極活物質集電体を有効活用する担い手となる。従って本発明によれば、鉛蓄電池の正極の耐久性信頼性を向上させることができ、鉛蓄電池および鉛蓄電池を使用したシステムの高信頼化、高効率化を図ることができる。
【図面の簡単な説明】
【図１】（Ａ）（Ｂ）は本発明に係る鉛蓄電池を捲回式鉛蓄電池に適用した実施の形態１の電池外観と内部電極構造を示す斜視図である。
【図２】本発明を適用した実施の形態１の捲回式鉛蓄電池の詳細な電池内部電極構造を示す断面図である。
【図３】実施の形態１の正極板の溶出、腐食現象による電池機能上の信頼性低下を回復し、高信頼性を有する鉛蓄電池構造に関する本発明の評価内容を示す評価フロー図である。
【図４】実施の形態２の正極板の展開構造を示す斜視図である。
【図５】実施の形態３の正極板の展開構造を示す斜視図である。
【符号の説明】
１ 電池容器
２ 正極端子
３ 負極端子
４ 負極板
５ 正極板
６ リテーナ
７ 内部正極取出し部
８ 内部負極取出し部
９ 正極集電体
１０ 正極活物質集電体
１１，１１ａ，１１ｂ 正極集電体保護層
１２ 接続部材
１３ 正極活物質層
１４ 負極活物質集電体
１５ 負極活物質[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lead storage battery.
[0002]
[Prior art]
Lead storage batteries are secondary batteries (storage batteries) that are particularly excellent in low-temperature characteristics and are well balanced in battery characteristics and cost. Lead storage batteries have a higher weight per unit volume than lithium secondary batteries and the like, and have a fundamental problem in terms of energy density. The reason is that a heavy lead electrode is used and sulfuric acid having a high specific gravity is used for the electrolyte.
[0003]
However, a wound lead-acid battery with a thinner lead electrode, a wider electrode area per unit weight, and a negative electrode plate and a positive electrode plate wound with a retainer (diaphragm) interposed therebetween has a high energy density. Can be expected. If the electrode is thinned and formed into a thin film and wound, a battery having a light-weight and large-area electrode can be formed, so that a high energy density can be obtained.
[0004]
For example, in order to form a wound lead storage battery, a lead storage battery in which a thin electrode is wound without damage has been proposed (for example, see Patent Document 1).
[0005]
There is also a disclosure of details regarding a wound sealed lead storage battery (for example, see Non-Patent Document 1).
[0006]
Further, a method has been proposed in which a BaPbO 3 (barium metaplumbate) film is formed on a lead electrode to improve the corrosion resistance of the lead electrode (for example, see Patent Document 2).
[0007]
[Patent Document 1]
JP-A-6-203870
[Non-patent document 1]
GS News Technical Report, No. 2, Vol. 58, December 1999, "Development of Cylindrical High-Power Sealed Lead Battery"
[0009]
[Patent Document 2]
JP-A-7-272727
[Problems to be solved by the invention]
In a wound type lead-acid battery, as the electrode thickness can be reduced, the surface area increases with respect to the same weight as the electrode thickness is reduced, so that the energy density is increased. However, a lead-acid battery reaction that has a function in sulfuric acid is also a battery in which deterioration due to corrosion of the lead electrode progresses at the same time, and thinning of the lead electrode simultaneously reduces the risk of battery function deterioration and function stop due to electrode corrosion and breakage. With the accompanying basic technical issues.
[0011]
Particularly, in a wound type lead-acid battery, since the corrosion rate of the positive electrode plate is high, the problem in thinning the electrode is mainly on the positive electrode plate side. Corrosion phenomena due to thinning induces breakage of the positive electrode plate, etc., and suddenly stops the battery function, etc., and thus suppresses battery function deterioration and stop due to corrosion phenomena accompanying thinning of electrodes required for wound lead storage batteries. Technology is needed.
[0012]
An object of the present invention is to provide a lead-acid battery that can improve corrosion resistance by the structure of a positive electrode plate.
[0013]
[Means for Solving the Problems]
In a lead-acid battery, the method of improving the corrosion resistance of a lead positive electrode plate, which is important in thinning the electrodes, is to directly improve the corrosion resistance itself of the positive electrode plate.However, the corrosion resistance is improved by the structure of the positive electrode plate, It is possible to extend the service life and increase the reliability of the positive electrode plate.
[0014]
That is, the present invention relates to a lead-acid battery, which is stacked and accommodated in a battery container with a retainer containing an electrolytic solution interposed between a positive electrode plate and a negative electrode plate, wherein the positive electrode plate has a positive electrode active material layer having a positive electrode active material layer. A current collector, a positive electrode current collector having no positive electrode active material layer, and a positive electrode current collector protective layer interposed therebetween are laminated, and the positive electrode active material current collector and the positive electrode current collector are electrically connected. The positive electrode current collector having no positive electrode active material layer does not face the negative electrode plate, and the positive electrode active material current collector having the positive electrode active material layer has a structure facing the negative electrode plate. It is characterized by.
[0015]
According to the lead-acid storage battery having such a configuration, the positive electrode active material current collector facing the negative electrode plate is broken by corrosion, and the island-like (island-shaped) dispersed break state of the positive electrode plate due to the break occurs. Even in such a state, the positive electrode current collector that does not face the negative electrode plate does not break due to corrosion and does not have an island-like (island-like) dispersed fracture state of the positive electrode plate due to the break. For this reason, even when the positive electrode active material current collector is broken, electrons of the battery reaction can maintain electrical contact with the negative electrode plate through the positive electrode current collector. Therefore, according to the present invention, the corrosion resistance can be improved by the structure of the positive electrode plate. In addition, the positive electrode current collector protective layer interposed between the positive electrode current collector and the positive electrode active material current collector plays a role of suppressing elution of the positive electrode current collector, and the positive electrode active material dispersed and broken in an island shape. Become a leader in effectively utilizing the substance current collector.
[0016]
In the present invention, the positive electrode current collector requires higher reliability than the positive electrode active material current collector. For this reason, in the present invention, the positive electrode current collector preferably has corrosion resistance equal to or higher than that of the positive electrode active material current collector.
[0017]
Further, in the lead storage battery of the present invention, the positive electrode active material current collector having the positive electrode active material layer is disposed on both surfaces of the positive electrode current collector having no positive electrode active material layer via the positive electrode current collector protection layer. Is preferred. With such a configuration, the negative electrode plates can be arranged on both surfaces of the positive electrode plate. Therefore, the present invention can be applied to a wound lead storage battery.
[0018]
Further, in the lead storage battery of the present invention, the positive electrode current collector protective layer may be made of a material having electrical insulation or a material having electron conductivity.
[0019]
In addition, the positive electrode current collector protective layer may be a material having electric insulation or a material having electron conductivity to which an electron conductive substance is added. As the electron conductive substance, one or more selected from lead oxide (PbO 2-x ), stannic oxide (SnO 2 ), and barium metaplumbate (BaPbO 3 ) can be used.
[0020]
The material having electrical insulation properties may be either a material that transmits water and electrolyte ions in the electrolyte or a material that does not transmit water and electrolyte ions in the electrolyte.
[0021]
The material having electron conductivity may be either a material that transmits water and electrolyte ions in the electrolyte or a material that does not transmit water and electrolyte ions in the electrolyte.
[0022]
Further, in the lead storage battery of the present invention, it is preferable that the positive electrode plate, the negative electrode plate, and the retainer containing the electrolytic solution interposed between these two electrodes are wound and laminated. With this configuration, a wound lead storage battery can be configured. In this case, in the positive electrode plate, a positive electrode active material current collector having a positive electrode active material layer is disposed on both sides of a positive electrode current collector having no positive electrode active material layer via a positive electrode current collector protective layer, It is preferable that the current collector and the positive electrode current collector be electrically connected to each other. Structurally, the positive electrode current collector does not need to be lead, but materials that degrade the electrochemical overvoltage characteristics of the positive and negative plates with respect to oxygen and hydrogen generation must be avoided. For this reason, the easiest material for forming the positive electrode current collector is lead having the same composition as the positive electrode active material current collector.
[0023]
A positive electrode active material current collector having a positive electrode active material layer in an island-shaped (island-shaped) dispersed rupture state of a positive electrode plate caused by corrosion of a wound positive electrode active material current collector that has been made as thin as possible. Are disposed on both sides of a positive electrode current collector having no positive electrode active material layer via a positive electrode current collector protective layer, and the configuration in which the positive electrode active material current collector and the positive electrode current collector are electrically connected includes a positive electrode It is possible to effectively function the positive electrode plate in which the active material current collector has been broken and the island has been dispersed and broken. That is, even if the cathode active material current collector having the cathode active material layer is broken by the cathode current collector between the wound cathode active material current collectors, the electrons of the battery reaction pass through the cathode current collector. Electrical contact with the negative electrode plate can be maintained. In this sense, the positive electrode current collector needs to have higher reliability than the positive electrode active material current collector having the positive electrode active material layer. The positive electrode current collector protective layer pressed on both sides of the positive electrode current collector plays a role in suppressing elution of the positive electrode current collector, and also plays a role in effectively utilizing the positive electrode active material current collector that has been dispersed and broken in an island shape. . In order to enhance the corrosion resistance of the positive electrode current collector, it is important that the sulfuric acid as the electrolyte does not come into direct contact with the positive electrode current collector. In order to effectively utilize the positive electrode active material current collector that has been dispersed and broken in an island shape, a material having electronic conductivity may be used as the positive electrode current collector protective layer. Even in the case where the positive electrode current collector protective layer itself has no electron conductivity, the same function can be obtained by applying an electronic conductive material such as PbO 2 to a synthetic fiber, for example. In the case where the corrosion resistance of the positive electrode current collector is to be increased, a material having a high shielding property against sulfuric acid may be selected as the positive electrode current collector protective layer. Therefore, functional deterioration and short-life phenomena due to breakage of the positive electrode active material current collector of the wound lead storage battery, which need to be thinned, are collected in the middle of the two positive electrode active material current collectors having the positive electrode active material layer. This can be suppressed by combining a positive electrode current collector having a current collecting function and a positive electrode current collector protection layer having a function of protecting the positive electrode current collector. In this case, the configuration of the positive electrode plate in contact with the negative electrode plate is, in the case of a wound lead storage battery, a negative electrode active material current collector / anode active material / retainer / a positive electrode active material / a positive electrode active material current collector / a positive electrode current collector protective layer. / A positive electrode current collector / a positive electrode current collector protective layer / a positive electrode active material current collector / a positive electrode active material / a retainer / a negative electrode active material / a negative electrode active material current collector. The retainer is a diaphragm containing a sulfuric acid solution, and has a function of suppressing electrical short-circuit between the positive electrode plate and the negative electrode plate, and of impregnating sulfuric acid containing a proton, which is one of the reaction active materials.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0025]
(Embodiment 1)
1 (A) and 1 (B) are perspective views showing a battery appearance and an internal electrode structure of a first embodiment in which a lead storage battery according to the present invention is applied to a wound lead storage battery. In this wound lead storage battery, FIG. 1A is an external structural view in which a positive electrode terminal 2 and a negative electrode terminal 3 are provided on the upper and lower sides of a resin battery case (container) 1. As shown in FIG. 2B, the electrode structure inside the battery is such that a negative electrode plate 4 and a positive electrode plate 5 are wound with a retainer 6 containing an electrolyte such as sulfuric acid interposed therebetween. The retainer 6 has a function including an electrolytic solution necessary for a battery reaction and a role as a separator for breaking an electrostatic ohmic contact between the negative electrode plate 4 and the positive electrode plate 5 to prevent an electric short circuit. The internal positive electrode extracting section 7 is connected to the positive electrode terminal 2, and the internal negative electrode extracting section 8 is connected to the negative electrode plate 3.
[0026]
FIG. 2 is a sectional view showing a detailed internal electrode structure of the wound lead storage battery according to Embodiment 1 to which the present invention is applied. The central positive electrode plate 5 has a triple structure of a thin lead plate. That is, the positive electrode plate 5 is provided with a positive electrode active material current collector 10 made of lead via a sheet-shaped positive electrode current collector protection layer 11 on both left and right sides of a positive electrode current collector 9 made of lead located in the middle. The positive electrode current collector 9 and the left and right positive electrode active material current collectors 10 are electrically connected by a connection member 12. The positive electrode current collector 9 located in the middle mainly plays a role of backing up the movement of the electrons accompanying the battery reaction coming and going between the positive electrode plate 5 and the negative electrode plate 4. The positive electrode current collector protection layer 11 has a function of suppressing the behavior of the positive electrode current collector 9 corroding and eluting in the battery positive electrode reaction. A positive electrode active material layer 13 is pressure-coated on both surfaces of each positive electrode active material current collector 10. Outside the positive electrode active material current collector 10 to which the positive electrode active material layer 13 is applied, a negative electrode active material current collector 14 is disposed via a retainer 6. The negative electrode active material 15 is pressure-coated on each negative electrode active material current collector 14. The negative electrode plate 4 is composed of the negative electrode active material current collector 14 and the negative electrode active material 15. The positive electrode plate 5, the retainer 6, and the negative electrode plate 4 are spirally wound as a whole. It is preferable that the wound positive electrode plate 5 uses a positive electrode current collector 9 and a positive electrode active material current collector 10 that are as thin as possible.
[0027]
In such a lead-acid battery, the positive electrode current collector 9 having no positive electrode active material layer does not face the negative electrode plate 4, and the positive electrode active material current collector 10 having the positive electrode active material layer 13 faces the negative electrode plate 4. It has become.
[0028]
FIG. 3 is an evaluation flow chart showing the evaluation contents of the present invention relating to a lead-acid battery structure having high reliability by recovering from deterioration in battery function reliability due to elution and corrosion of the positive electrode plate 5 of the first embodiment. . In the evaluation flow chart, the structure in which the positive electrode current collector 9 is sandwiched between the positive electrode current collector protective layers 11 and the material of the positive electrode current collector protective layer 11 are determined by the corrosion resistance of the positive electrode plate 5 and the effective use of the positive electrode plate 5. Hold the key above.
[0029]
The material of the positive electrode current collector protection layer 11 is roughly classified into two contents. One is whether or not the material of the positive electrode current collector protective layer 11 has electric conductivity (including ionic conductivity) necessary for exchange of electrons for battery reaction. Whether or not the conductor protection layer 11 is made of a material through which water, an electrolyte, and the like can pass. The simplest structure of a material through which water, electrolyte, and the like pass is a porous material. The positive electrode current collector protective layer 11 can be used effectively even if the positive electrode active material current collector 10 coated with the positive electrode active material layer 13 is broken or isolated and dispersed in an island shape. A function to prevent elution is required. The material of the positive electrode current collector protective layer 11 which is the most excellent in this point has electron conductivity itself, is excellent in oxygen generation overvoltage characteristics, and can suppress corrosion of the underlying positive electrode current collector 9, that is, lead ion. It is a material that cannot pass through and has good water-impermeable membrane characteristics (indicated by ◎ in FIG. 3). The fact that the material of the positive electrode current collector protective layer 11 has electron conductivity enables the transfer of electrons generated by a battery reaction on lead dispersed in islands due to elution of the positive electrode active material current collector 10. Thus, electrons generated by the battery reaction between the positive electrode plate 5 and the negative electrode plate 4 can be moved, and the charge function and the like can be effectively utilized. If the material of the positive electrode current collector protective layer 11 does not have electronic conductivity, in the case of a so-called electric insulating material, the portion left after being corroded in an island shape cannot be utilized for the battery reaction. However, the role as a protective film for elution of the underlying positive electrode current collector 9 remains, and even when the positive electrode active material current collector 10 coated with the positive electrode active material layer 13 is broken up and down, the positive electrode current collector Reference numeral 9 plays a role as a current collecting unit, and high durability and high reliability of the battery can be achieved.
[0030]
The low-R (R is an electrical resistance) material in FIG. 3 is a material that can minimize the adverse effects on battery voltage characteristics, oxygen overvoltage, and hydrogen overvoltage characteristics due to deposition of a negative electrode plate when eluted. And reliable in sulfuric acid. The high R material basically corresponds to an ordinary sulfuric acid resistant chemical fiber, a resin film or the like. In FIG. 3, △, Δ, and Δ indicate qualitative evaluation results on material evaluation of the positive electrode current collector protective layer 11. Double circles 最 も are the ones that can best utilize the object of the present invention, and are sequentially △ and Δ.
[0031]
The positive electrode current collector protection layer 11 is roughly classified into a low R material and a high R material surrounded by a broken line, and a high R material is easily obtained. In the case of a high-R material that cannot pass water, it is basically difficult to utilize lead (Pb) left in an island shape, but the protection function of the positive electrode current collector 9 is maintained. When the positive electrode current collector protective layer 11 itself can pass water at a high R, that is, can pass so-called electrolyte ions, it is basically difficult to utilize lead (Pb) similarly left in an island shape. However, in this case, the use of lead (Pb) left in the form of an island becomes more advantageous as compared with a high-R, water-impermeable material due to the interposition of the active material of the battery itself. The use of lead (Pb) left in the shape of an island can be further utilized. However, in the case of the positive electrode current collector protective layer 11 through which water can be passed at a high R, basically, the lead ions of the positive electrode current collector 9 can be dissolved into the solution. For this reason, the corrosion rate of the positive electrode current collector 9 tends to be higher than the material of the water-impermeable positive electrode current collector protective layer 11.
[0032]
(Embodiment 2)
FIG. 4 is a perspective view showing a developed structure of the positive electrode plate 5 according to the second embodiment in which the positive electrode current collector 9 is combined with a positive current collector protective layer 11a having a high electric resistance. The positive current collector protective layer 11a having a high electric resistance is formed of a normal resin-based material, for example, a polypropylene resin or the like. The positive electrode current collector 9 is connected to the positive electrode active material current collector 10 by a connection member 12 made of lead. The internal positive electrode take-out part 7 is connected to the connection member 12. In this case, there is one internal positive electrode extracting portion 7, but a structure in which internal positive electrode extracting portions 7 are provided from two upper and lower portions is also functionally effective.
[0033]
Also in the lead storage battery having such a positive electrode plate 5, the positive electrode current collector 9 having no positive electrode active material layer does not face the negative electrode plate 4, and the positive electrode active material current collector 10 having the positive electrode active material layer 13 has the negative electrode plate. 4.
[0034]
(Embodiment 3)
FIG. 5 shows that BaPbO 3 in which water passes around the positive electrode current collector 9 but is itself made of an electrically insulating synthetic polyethylene fiber sheet, and the gap between the fibers is filled with BaPbO 3 which is a conductive substance. FIG. 13 is a perspective view showing a developed structure of a positive electrode plate 5 according to a third embodiment in which a three- filled positive electrode current collector protective layer 11b is combined. In addition to BaPbO 3 , PbO 2 , SnO 2, or the like, or an elution component thereof, has a hydrogen overvoltage on the negative electrode plate 4 and an oxygen overvoltage characteristic on the positive electrode plate 5 that does not adversely affect battery design and function. Substances can be applied. Unlike the type in which water or electrolyte penetrates through the gap of the fiber-made positive electrode current collector protective layer, when a polypropylene resin that does not allow water to pass is used, BaPbO 3 is applied to the resin surface by pressure bonding. Become.
[0035]
Also in the lead storage battery having such a positive electrode plate 5, the positive electrode current collector 9 having no positive electrode active material layer does not face the negative electrode plate 4, and the positive electrode active material current collector 10 having the positive electrode active material layer 13 has the negative electrode plate. 4.
[0036]
In each of the above examples, the case where the present invention is applied to a wound lead storage battery has been described. However, the present invention is not limited to this, and the flat negative plate 4 and the flat positive plate 5 are The present invention can be similarly applied to a lead-acid battery laminated via the same. Also in this case, the positive electrode plate 5 has the above-described configuration, and the positive electrode current collector 9 having no positive electrode active material layer does not face the negative electrode plate 4 and the positive electrode active material current collector 10 having the positive electrode active material layer 13 Is configured to face the negative electrode plate 4.
[0037]
【The invention's effect】
In the lead storage battery according to the present invention, the positive electrode plate includes a positive electrode active material current collector having a positive electrode active material layer, a positive electrode current collector having no positive electrode active material layer, and a positive electrode current collector interposed therebetween. A protective layer is laminated, and the positive electrode active material current collector and the positive electrode current collector are electrically connected to each other. The positive electrode current collector having no positive electrode active material layer does not face the negative electrode plate and has a positive electrode active material. Since the positive electrode active material current collector having the material layer faces the negative electrode plate, the positive electrode active material current collector facing the negative electrode plate is broken due to corrosion, and the positive electrode plate is dispersed in an island shape (island shape) due to the break. Although a rupture state occurs, the positive electrode current collector that does not face the negative electrode plate does not break due to corrosion and does not generate an island-like (island-like) dispersed rupture state of the positive electrode plate due to breakage. For this reason, even when the positive electrode active material current collector is broken, electrons of the battery reaction can maintain electrical contact with the negative electrode plate through the positive electrode current collector. Therefore, according to the present invention, the corrosion resistance can be improved by the structure of the positive electrode plate. In addition, the positive electrode current collector protective layer interposed between the positive electrode current collector and the positive electrode active material current collector plays a role of suppressing elution of the positive electrode current collector, and the positive electrode active material dispersed and broken in an island shape. Become a leader in effectively utilizing the substance current collector. Therefore, according to the present invention, the durability and reliability of the positive electrode of the lead storage battery can be improved, and the reliability and efficiency of the lead storage battery and the system using the lead storage battery can be improved.
[Brief description of the drawings]
FIGS. 1A and 1B are perspective views showing a battery appearance and an internal electrode structure of a first embodiment in which a lead storage battery according to the present invention is applied to a wound lead storage battery.
FIG. 2 is a sectional view showing a detailed internal electrode structure of the wound lead storage battery according to the first embodiment to which the present invention is applied.
FIG. 3 is an evaluation flow chart showing evaluation contents of the present invention relating to a lead-acid battery structure having high reliability by recovering from deterioration in battery function reliability due to elution and corrosion of the positive electrode plate of Embodiment 1;
FIG. 4 is a perspective view showing a development structure of a positive electrode plate according to a second embodiment.
FIG. 5 is a perspective view showing a development structure of a positive electrode plate according to a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery container 2 Positive electrode terminal 3 Negative electrode terminal 4 Negative electrode plate 5 Positive electrode plate 6 Retainer 7 Internal positive electrode take-out part 8 Internal negative electrode take-out part 9 Positive current collector 10 Positive active material current collector 11, 11a, 11b Positive current collector protection layer 12 connection member 13 positive electrode active material layer 14 negative electrode active material current collector 15 negative electrode active material
