JP2004281156A

JP2004281156A - Vessel for electricity storage, vessel collective body for electricity storage, and manufacturing method thereof

Info

Publication number: JP2004281156A
Application number: JP2003069133A
Authority: JP
Inventors: Hiroshi Tada; 裕志多田; Saburo Yamashita; 三郎山下; Kentaro Fujii; 憲太郎藤井
Original assignee: Toyo Aluminum KK; Nissha Printing Co Ltd
Current assignee: Toyo Aluminum KK; Nissha Printing Co Ltd
Priority date: 2003-03-14
Filing date: 2003-03-14
Publication date: 2004-10-07

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vessel for electricity storage and a vessel collective body for electricity storage with excellent weight reduction, mass productivity in installing a lid, and insulation property of a terminal part, including a case for a battery other than a lithium ion secondary battery or a capacitor; and to provide their manufacturing method. <P>SOLUTION: This vessel for electricity storage comprises: a bottomed cylindrical resin solid vessel 2 having electrolyte resistance; and a moisture-proof sheet 3 covering the outside bottom surface 2b and the outside surface 2a of the vessel 2; and the moisture-proof sheet 3 is composed by laminate at least a corrosion-resistant resin layer and aluminum foil in that order from the outside. Since the material the vessel comprises the resins and the aluminum foil, the weight of the vessel can be further reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術の分野】
本発明は、軽量化、蓋をする際の量産性、端子部の絶縁性に優れた蓄電用容器、蓄電用容器集合体及びこれらの製造方法に関するものである。
【０００２】
【従来の技術】
非特許文献１には、リチウムイオン二次電池ケース用としてアルミ合金板材が新たに開発され、溶接性はそのままで、強度のみを向上させる元素配合及び圧延技術が確立されたことが開示されている。リチウムイオン二次電池は、小型、高電圧で繰り返しの充電にも適していることから、主に携帯電話、ノートパソコン等のバッテリーとして用いられ、今後も使用の拡大が大いに期待されているものである。またハイブリットカーや電気自動車、燃料電池自動車等のバッテリーとしても注目されている。このようなリチウムイオン二次電池のケース（外装缶材料）としては、従来、スチール板材が主に採用されていたが、近年、軽量化ニーズから急速にアルミニウム板材への変更が進んでいる。ケース用のアルミニウム板材には成形性、溶接性（上部に蓋をし、溶接する為）が高いことに加え、電池内部の圧力上昇に耐えるため、耐ふくれ性が高いことが求められる。更に、電池の小型化によりケースの薄肉化が進み、アルミニウム板材に対する強度要求は年々増加傾向にある。前記の新アルミ合金板材は、これらのニーズに対応するため、従来の「ＪＩＳＡ３００３Ｐ（Ａｌ−Ｍｎ合金）」を改良し強度を向上させ、同時に溶接時の割れ防止を図ったものであり、「Ａ３００３Ｐ」合金と同レベルの溶接性と成形性を維持しながら、引張強度を１５〜２０％向上させるものであった。
【０００３】
【非特許文献１】
広報・ＩＲ室、“リチウムイオン二次電池ケース用アルミニウム板拡販に注力”、［ｏｎｌｉｎｅ］、平成１４年１１月１３日、日本軽金属株式会社、ＮｉｋｋｅｉｋｉｎＧｒｏｕｐＮｅｗｓ、［平成１４年１２月１８日検索］、インターネット＜ＵＲＬ：ｈｔｔｐ：／／ｗｗｗ．ｎｉｋｋｅｉｋｉｎ．ｃｏ．ｊｐ／ｐａｇｅｓ／ｐｒｅｓｓ／Ｐ２００２／ｐ２００２１１１３．ｈｔｍ＞
【０００４】
【発明が解決しようとする課題】
しかしながら、上記のリチウムイオン二次電池のケースは、アルミニウム板材であっても金属製であることにはかわりなく、軽量化に限界があった。特にハイブリットカーや電気自動車、燃料電池自動車等の用途では、電池も大きくなるため、前記問題点はより顕著となる。
【０００５】
また、上記しているように上部に蓋をするために溶接が必要となるが、アルミニウムは、熱伝導度が大きい為局部的に加熱するのが困難であり、アルミニウムの溶接・接合には熟練を要する。特性的には、凝固時の体積収縮、線膨張係数が大きい為、溶接歪みが生じ易く、また合金によっては割れが生じることもある。また、表面に強固な酸化皮膜が存在するので、多量のフラックスが必要であり、酸化皮膜に共存する結晶水は、溶接部のブローホール等の溶接欠陥の原因にもなる。さらに化学的に活性な金属である為、不活性ガス等で表面を保護する必要がある。このため不活性ガスアーク溶接（ＴＩＧ溶接・ＭＩＧ溶接）が多用されているが、この方法は多量の不活性ガスや高価なタングステン電極もしくは消耗電極が必要な為、量産には適していない。圧接法は、高圧力を利用する為、厚板では可能であるが、薄いアルミニウム板（箔）には不向きである。その他、電子ビーム溶接やプラズマ溶接等が考えられるが、開発途上のものが多く、また装置が高価である等の理由で、工業的には普及していない。従って、溶接工程を含むことは量産に不向きである。
【０００６】
また、ケース全体が導電性材料からなるため、端子部の絶縁性を図るために絶縁性セラミックス、絶縁性樹脂・ゴム等の絶縁性部材を端子部周辺に係合又は螺合しなければならない。しかしながら、水分の付着や不用意な作業によって端子部とケースとがショート（短絡）する危険性が常にある。ショートを完全に防止するには、ケース全体を絶縁性材料で被覆しなければならず、コスト、量産性の点で不利であった。
【０００７】
したがって、本発明の目的は、上記の問題点を解決し、軽量化、蓋をする際の量産性、端子部の絶縁性に優れた、リチウムイオン二次電池以外の電池やキャパシタ用のケースをも含む蓄電用容器、蓄電用容器集合体及びこれらの製造方法を提供することにある。
【０００８】
【課題を解決するための手段】
上記目的を達成するために、本発明の蓄電用容器は、耐電解液性を有する筒状の樹脂固型容器と、該樹脂固型容器の外側面を覆う防湿シートとからなり、該防湿シートが外側より少なくとも防蝕性樹脂層、アルミニウム箔の順で積層してなるものであるように構成した。
【０００９】
また、本発明の蓄電用容器の製造方法は、射出成形用の金型の内壁に、金型側より少なくとも防蝕性樹脂層、アルミニウム箔の順で積層してなる防湿シートを沿わせて配置し、次いでキャビティ内にて耐電解液性を有する樹脂を射出成形することにより、筒状の樹脂固型容器を得ると同時に該樹脂固型容器の外側面を防湿シートにて覆うように構成した。
【００１０】
また、本発明の蓄電用容器の製造方法は、耐電解液性を有する筒状の樹脂固型容器を予め用意し、該樹脂固型容器の外側面を、外側より少なくとも防蝕性樹脂層、アルミニウム箔の順で積層してなる防湿シートを重ね合わせて接着することにより覆うように構成した。
【００１１】
また、上記各構成において、樹脂固型容器が有底筒状であり、樹脂固型容器の外底面および外側面を防湿シートにて覆うように構成した。
【００１２】
さらに、本発明の蓄電用容器の製造方法は、ブロー成形用の金型の内壁に、金型側より少なくとも防蝕性樹脂層、アルミニウム箔の順で積層してなる防湿シートを沿わせて配置し、次いでキャビティ内にて耐電解液性を有する樹脂をブロー成形することにより、有底筒状の樹脂固型容器を得ると同時に該樹脂固型容器の外底面および外側面を防湿シートにて覆うように構成した。
【００１３】
また、上記外底面も防湿シートにて覆う各構成において、樹脂固型容器の外底面を覆う防湿シートと樹脂固型容器の外側面を覆う防湿シートとが別体であるように構成した。
【００１４】
また、上記各構成において、防湿シートが、アルミニウム箔の樹脂固型容器側に熱接着性樹脂層を積層してなるように構成した。
【００１５】
また、本発明の蓄電用容器集合体は、上記蓄電用容器が開口方向を揃えて複数並べられ、結束体により束ねられたものであるように構成した。
【００１６】
また、本発明の蓄電用容器集合体の製造方法は、上記蓄電用容器を複数用い、これを開口方向を揃えて射出成形用の金型内に並べ、次いでこれらの蓄電用容器の防湿シートを有する面と金型との間に形成されたキャビティに溶融された樹脂を射出することにより、結束体を成形すると同時に該結束体により蓄電用容器を束ねるように構成した。
【００１７】
上記蓄電用容器および蓄電用容器集合体は、その構成によって従来のアルミニウム板からなる容器では得られない、次のような特徴を有する。すなわち、材料が樹脂とアルミニウム箔とからなるため、さらなる軽量化を図ることができる。
【００１８】
また、上記しているように上部に蓋をする際には、嵌合、接着剤による接着、ヒートシール、圧入、螺合等すれば済み、従来技術のように溶接は不要である。そのため、上記蓄電用容器および蓄電用容器集合体は、蓋をする際の量産性に優れる。
【００１９】
また、蓄電用容器の最も内側は樹脂材料からなるため絶縁性を有し、端子部の絶縁性を図るための複雑な部材設計の必要性がなく、電池容器と端子部のショ−トという問題は生じない。
【００２０】
【発明の実施の形態】
以下に、図を参照しながら本発明に係る蓄電用容器、蓄電用容器集合体及びこれらの製造方法について詳細に説明する。
【００２１】
図１に示す蓄電用容器１は、耐電解液性を有する有底筒状の樹脂固型容器２（図２参照）と、該樹脂固型容器２の外底面２ｂおよび外側面２ａを覆う防湿シート３とからなり、該防湿シート３が外側より防蝕性樹脂層５、アルミニウム箔６、熱接着性樹脂層７の順で積層してなるもの（図３参照）である。また、樹脂固型容器の外底面２ｂを覆う防湿シート３と樹脂固型容器２の外側面２ａを覆う防湿シートとが別体である。
【００２２】
上記樹脂固型容器２は、蓄電用容器１について容器としての形状および強度を付与するためのものである。樹脂固型容器２は、次ぎの理由から、射出成形またはブロー成形によるのが好ましい。射出成形（ＩｎｊｅｃｔｉｏｎＭｏｌｄｉｎｇ）は、樹脂材料を加熱して流動状態にし、閉じた金型の空洞部（キャビティ）に加圧注入し金型内で固化させることにより、金型空洞部に相当する形を造る方法である。またブロー成形は、ダイスから溶融状態のパリソンと呼ばれる筒状の樹脂を押出し、金型を型閉めした後、閉じられたパリソン内に加圧気体を吹き込み、パリソンを型内いっぱいに膨張させ中空の製品を作る成形法である。したがって、これらの方法によって得られる成形品は、形状の選択の幅が広く、また従来のアルミニウム板からなる容器と同様に、電池内部の圧力上昇にも耐え得る耐ふくれ性の高いものである。
【００２３】
上記樹脂固型容器２は、後述するように蓄電用容器１が開口方向を揃えて複数並べられ、結束体により束ねられた蓄電用容器集合体４として使用されるため、例えば口径に対し深さ方向が大きい有底筒状にその容量が５０ｃｃ以上となるように成形される。また、樹脂固型容器２の外底面２ｂおよび外側面２ａを防湿シート３にて覆うため、この筒の形は図１に示すような円筒や角筒（図４参照）とするのが好ましい。この円筒や角筒の内壁面は、開口部が裾拡がりとなるようにテーパーを持っているものでもよい。なお、樹脂固型容器２及び蓄電用容器集合体４の肉厚は、特に制限されるものではないが、材質強度、耐ふくれ性及び設置スペ−スの点より０．５〜１０ｍｍが望ましい。
【００２４】
上記樹脂固型容器２の材質としては、耐電解液性・ガスバリア性・耐熱性・加工適性のあるものを用いる。例えば、ポリエチレン・ポリプロピレン・ＴＰＸ等のポリオレフィン樹脂、ＰＥＴ・ＰＥＮ・ＰＢＴ等のポリエステル樹脂、ＰＭＭＡ・ＢＭＡ・ＥＭＡ等のアクリル樹脂、ＡＢＳ・スチレン・ＡＳ等のスチレン系樹脂、塩化ビニル・酢酸ビニル・塩酢ビ共重合樹脂・塩酢ビマレイン酸共重合樹脂・エチレンビニルアルコール等のビニル樹脂、ナイロン６・ナイロン６６等のポリアミド樹脂、フッソ系樹脂、シリコーン樹脂等の単体及びこれら複合物が使用できる。このうちポリオレフィン樹脂、特にポリプロピレン樹脂が、前記耐電解液性・ガスバリア性・耐熱性・加工適性の点で優れているため望ましい。
【００２５】
上記防湿シート３に用いるアルミニウム箔６は、外部から蓄電用容器１内部に水蒸気ガスや酸素ガスが侵入することを防止するためのガスバリア層であり、ガスバリア性の確保や加工適性その他を考慮すると、その厚みは６〜２００μｍの範囲とするのが好ましい。アルミニウム箔６の厚みが６μｍに満たないと、ピンホールの発生が極端に多くなり、ガスバリア性が低下する。また、アルミニウム箔６の厚みが２００μｍを超えると、熱が逃げ易く、また重量が大きくなることに加え、経済的に望ましくない。上記アルミニウム箔の成分は特に限定されるものではなく、公知の純アルミニウムまたはアルミニウム合金が使用できる。また調質は、硬質、半硬質、軟質等のいずれであっても良く適宜選択すれば良い。また、アルミニウム箔は、必要に応じ、公知の方法で脱脂・洗浄、アンカーコート、プライマーコート、表面処理（クロム酸処理等）等を施すこともできる。
【００２６】
アルミニウム箔６の外側に積層される防蝕性樹脂層５は、他物品との機械的な接触によるアルミニウム箔６の亀裂・穴開き・剥離・破断等の発生を防止し、また水分や不用意な電解液等の付着によるアルミニウム箔６の腐食を防止することを目的に設けられるものである。防蝕性樹脂層５に用いる材料としては、ポリエチレン系（ＨＤＰＥ、ＬＤＰＥ、ＬＬＤＰＥ等）、ポリエステル系（ＰＥＴ、ＰＥＮ、ＰＢＴ等）、ポリプロピレン（延伸ＰＰ、無延伸ＰＰ）、ポリアミド系（ナイロン、ＭＸＤナイロン等）、ポリ塩化ビニリデン、塩化ビニル、フッソ系、エチレン−ビニルアルコール共重合体、ポリカーボネート等の樹脂フィルム、またはエポキシ樹脂、アクリル樹脂、ポリエステル樹脂、ポリオレフィン樹脂、フッ素樹脂系の防食コ−ト剤を用いることができる。特に、フィルムではポリエチレン系（ＨＤＰＥ）、ポリエステル系（ＰＥＴ）、ポリプロピレン（延伸ＰＰ、無延伸ＰＰ）が柔軟性、コスト、強度等のトータルバランスの点でまたコ−ト剤としては焼き付けタイプのエポキシ樹脂、アクリル樹脂が耐食性、コストの点より好ましい。防蝕性樹脂層５に用いるフィルムの厚みは、１２〜８０μｍの範囲が、コ−ト剤としては２〜３０μｍとするのが好ましい。フィルムでは厚みが１２μｍに満たないと、ピンホールの発生が多くなると共に、貼り合わせが困難となり皺等が発生する為、防蝕性が低下する。また、厚みが８０μｍを超えると、コストの上昇、熱接着不良の原因となる。樹脂コ−ト層の厚みとして２μｍ以下では耐食性が十分でなく、３０μ以上では塗工乾燥が困難となるだけでなく、コスト面でも好ましくない。
【００２７】
また、アルミニウム箔６にフィルム形態の防蝕性樹脂層５を積層する方法としては、周知のドライラミネート用接着剤を用いて周知のドライラミネーション法で積層することができる。また、積層方法としては、押出しラミネート、ウエットラミネート又はヒートラミネート等を採用することもできる。
【００２８】
また、本発明の防湿シート３においては、外側より少なくとも防蝕性樹脂層、アルミニウム箔の順で積層していればよいが、図３に示すようにアルミニウム箔６の樹脂固型容器２側に熱接着性樹脂層７が積層されている方が好ましい。この理由としては、熱接着性樹脂層７と樹脂固型容器２とを熱接着させることにより、防湿シート３を樹脂固型容器２に強く固着させることができるからである。接着力が弱いとそこから剥離したり、空気（水分）が侵入する恐れがある。熱接着性樹脂層７に用いる材料としては、例えば、高密度ポリエチレン、中密度ポリエチレン、低密度ポリエチレン、直鎖線状ポリエチレン、飽和ポリエステル、線状飽和ポリエステル、無延伸ポリプロピレン、塩素化ポリプロピレン、エチレン−アクリル酸共重合体、エチレン−メタアクリル酸共重合体、エチレン−エチルアクリレート共重合体、エチレン−メチルアクリレート共重合体、アイオノマー、エチレン−エチルアクリレート−無水マレイン酸三元共重合体、ポリオレフィン、カルボン酸変性ポリエチレン、カルボン酸変性ポリプロピレン、カルボン酸変性エチレン−酢酸ビニル、塩化ビニル、ポリスチレン等が挙げられる。また、製品名「ボンダイン」住友化学工業株式会社製、製品名「メルセンＭ」東ソー株式会社製等の市販品も使用することができる。これら熱接着性樹脂はフィルムの形態又は直接アルミニウム箔６に塗布して用いることができる。特に、接着性の点より樹脂容器に使用される同系の樹脂材料が好ましい。熱接着性樹脂層７の厚みはの厚みは、１〜８０μｍの範囲とするのが好ましい。厚みが１μｍに満たないと、熱接着強度が不十分となる恐れがある。また、厚みが８０μｍを超えると、端面から水分が混入する恐れがあり、バリアー性の点で好ましくない。
【００２９】
また、アルミニウム箔６にフィルム形態の熱接着性樹脂層７を積層する方法としては、周知のドライラミネート用接着剤を用いて周知のドライラミネーション法で積層することができる。また、積層方法としては、押出しラミネート、ウエットラミネート、ヒートラミネート又はホットメルト等を採用することもでき、またラッカータイプの熱接着剤を塗布してもよい。なお、アルミニウム箔６と熱接着性樹脂層７との間に補強樹脂フィルム等を介在させることもでき、補強樹脂フィルムとしては、厚み９〜５０μｍのポリエチレン系（ＨＤＰＥ、ＬＤＰＥ、ＬＬＤＰＥ等）、ポリエステル系（ＰＥＴ、ＰＥＮ、ＰＢＴ等）、ポリプロピレン（延伸ＰＰ、無延伸ＰＰ）、ポリアミド系（ナイロン、ＭＸＤナイロン等）、ポリ塩化ビニリデン、塩化ビニル、フッソ系、エチレン−ビニルアルコール共重合体、ポリカーボネート等を介在させることができる。
【００３０】
また、先に各層の厚みについて個々の好ましい理由を述べたが、防湿シート３全体の厚みとしては４０〜３００μｍの範囲とするのが好ましい。総厚が４０μｍに満たないと、防湿シート３に腰がないため、樹脂固型容器２を覆う際に扱いにくくなる。また、総厚が３００μｍを超えると、柔軟性低下、コスト上昇、熱接着不良、密着不良の原因となる。なお、上記で述べた各層以外に必要に応じて、印刷層、着色層、クッション層、オーバーコート層、接着強化層等を介在又は積層してもよく、また、任意の層に滑剤、腐食抑制剤、紫外線吸収剤等の添加剤・助剤を含ませてもよい。
【００３１】
以上のような本発明の蓄電用容器１は、次に示す方法によって樹脂固型容器２を防湿シート３で被覆して製造する。
【００３２】
すなわち、射出成形用の金型９の内壁に、金型９側より少なくとも防蝕性樹脂層５、アルミニウム箔６の順で積層してなる防湿シート３を沿わせて配置し（図５参照）、次いでキャビティに溶融された耐電解液性を有する樹脂を射出することにより、有底筒状に成形してなる樹脂固型容器２を得ると同時に該樹脂固型容器２の外底面２ｂおよび外側面２ａを防湿シート３にて覆うようにする。また、ブロー成形によって樹脂固型容器２を得ると同時に防湿シート３にて覆うようにしてもよい。
【００３３】
また、耐電解液性を有する有底筒状の樹脂固型容器２を予め用意し、該樹脂固型容器２の外底面２ｂおよび外側面２ａに、外側より少なくとも防蝕性樹脂層５、アルミニウム箔６の順で積層してなる防湿シート３を重ね合わせて接着することもできる（図６参照）。樹脂固型容器２の外底面２ｂを覆う防湿シート３と樹脂固型容器２の外側面２ａを覆う防湿シート３とが別体である場合、上記金型９を用いる方法よりこの方法の方がより好ましい。何故なら、複数の防湿シート３を金型９内に挿入し、金型９内壁に沿わせて保持するのは手間がかかるからである。なお、防湿シート３に熱接着性樹脂層７を設けて予め用意した樹脂固型容器２と熱接着性樹脂層７とを熱接着する場合、その手段には外加熱による場合と内加熱による場合とがある。外加熱による熱接着方法としては、熱ローラーのついた熱転写機、アップダウン転写機などを用いて防湿シート３の外側より熱圧をかける圧着法がある。また、内加熱による熱接着方法としては、接着させる界面、すなわちここでは樹脂固型容器２の外側面２ａおよび外底面２ｂと防湿シート３の熱接着性樹脂層７とを密着させておき、その上に超音波又は高周波をかけて界面を振動させ発熱させるウェルダー加工法がある
【００３４】
また、上記熱接着工程においては、防湿シート３を所定の形状にカットしたものを一枚一枚を送り出して樹脂固型容器２に熱接着させることも可能であるし、又このカットしたものを長尺の補助シートに等間隔で貼りつけておいてロール状になし、これを自動的に繰り出し、補助シート側から熱圧をかけカットした防湿シート３のみを樹脂固型容器２に熱接着し、補助シートを巻き取る方法（いわゆる転写ラミネート法）をとることも可能である。
【００３５】
ところで、図５および図６においては、樹脂固型容器２の外底面２ｂを覆う防湿シート３と樹脂固型容器２の外側面２ａを覆う防湿シート３とが別体となっている蓄電用容器１の製造方法が示されているが、本発明は、１枚の防湿シート３を樹脂固型容器２の形状に合わせて深絞り成形したものを用いて樹脂固型容器２を被覆するようにしても構わない。しかし、樹脂固型容器２の外底面２ｂを覆う防湿シート３と樹脂固型容器２の外側面２ａを覆う防湿シート３とが別体となる方が、アルミニウム箔６が薄くても比較的大型のものを製造できること、容器全体にわたりアルミニウム箔６が均一の厚みを有し、加工に際して水蒸気ガスの侵入するピンホール等が生成される危険が少ないという効果がある。なお、この外側面２ａと外底面２ｂとの境界で隙間があるとガスバリア性が損なわれるため、外側面２ａを覆う防湿シート３または外底面２ｂを覆う防湿シート３の一方についてその境界に臨む端部を継ぎ代部３ａとし、他方の防湿シート３の前記境界に臨む端部に二重に重ね合わせるようにするとよい（図６参照）。また、外側面２ａを覆う防湿シート３については、樹脂固型容器２の外側面２ａへの巻き始めの端部と巻き終わりの端部との間に隙間があるとガスバリア性が損なわれるため、両端部を二重に重ね合わせる部分（継ぎ代部３ａ）を設けるとよい（図６参照）。この継ぎ代部３ａを設ける場合、防湿シート３の内側および外側の互いに接する層は剥離しにくいものを選択する。
【００３６】
以上のような構成からなる本発明の蓄電用容器１は、これを開口方向を揃えて複数並べ、結束体８により束ねることにより蓄電用容器集合体４として使用される（図７，図８参照）。なお、図７，図８においては、３つの蓄電用容器１を用いて蓄電用容器集合体４としているが、本発明の蓄電用容器集合体４を構成する蓄電用容器１の数は２つ又は４つ以上であっても構わない。
【００３７】
上記結束体８は、設置安定性、取扱い性、量産性を確保するためのものであり、その態様としては、例えば、複数の蓄電用容器１を開口方向を揃えて射出成形用の金型内に並べ、次いでこれらの蓄電用容器１の防湿シート３を有する面と金型との間に形成されたキャビティに溶融された樹脂を射出することにより、結束体８を成形すると同時に該結束体８により蓄電用容器１を束ねたものとすることができる。この場合、図７に示すように蓄電用容器１どうしを接触させて束ねてもよいし、図８に示すように蓄電用容器１どうしを接触させずに束ねてもよい。また、この射出成形品からなる結束体８は、蓄電用容器１の底面を覆わなくても構わないし、さらに蓄電用容器１の側面の一部のみを覆うようにしてもよい。
【００３８】
上記射出成形品からなる結束体８の材質としては、例えば、ポリプロピレン、ポリエチレン、メチルメタアクリル樹脂、アクリル−スチレン共重合樹脂、ポリスチレン、ＡＢＳ、塩化ビニル、ポリアミド、ポリカーボネート、ポリアセタール、４弗化樹脂等の熱可塑性樹脂が使用できる。
【００３９】
また、結束体８の別の態様としては、ゴムやエラストマー等による固着もしくは結束、樹脂被覆金属線（又は板）による結束、あるいは熱収縮フィルムによるラッピング等を施したものとすることもできる。
【００４０】
【実施例】
（実施例１）内径４０ｍｍ、肉厚４ｍｍ、長さ１４０ｍｍの有底円筒状に射出成形してなるポリプロピレン樹脂固型容器を予め用意し、外側よりＣＰＰ（無延伸ポリプロピレン）フィルム３０μｍ／ウレタン系ドライ接着剤４μｍ／アルミニウム箔（Ａｌ純度９９．３重量％軟質材）３０μｍ／ウレタン系ドライ接着剤４μｍ／ＣＰＰフィルム３０μｍの順で積層してなる防湿シートを樹脂固型容器の外底面および外側面に個別に、重ね合わせて熱接着（温度：２００℃、時間：３ｓｅｃ、圧力：３ｋｇ／ｃｍ^２）することにより蓄電用容器を得た。なお、樹脂固型容器の外底面に熱接着した防湿シートおよび樹脂固型容器の外側面に熱接着した防湿シートは、いずれも幅２ｍｍの継ぎ代部を設けた。なお、試験用蓋材としてはＯＰニス１〜２μｍ／アルミニウム箔（Ａｌ純度９９．３重量％軟質材）４０μｍ／ウレタン系ドライ接着剤３〜４μｍ／ＣＰＰフィルム４０μｍを用い、後述の電解液等を充填後、容器開口部に熱板シール（温度：２００℃、時間：３ｓｅｃ、圧力：３ｋｇ／ｃｍ^２、シール幅：容器の肉厚）した。
【００４１】
（実施例２）実施例１の蓄電用容器を６つ用い、これを開口方向を揃えて射出成形用の金型内に並べ、次いでこれらの蓄電用容器の防湿シートを有する面と金型との間に形成されたキャビティに溶融されたポリプロピレン樹脂を射出することにより、肉厚２ｍｍの結束体を成形すると同時に該結束体により蓄電用容器を束ね、蓄電用容器集合体を得た。
【００４２】
（実施例３）口寸法２０ｍｍ×５０ｍｍ、肉厚１ｍｍ、長さ１４０ｍｍの有底角筒状に射出成形してなる高密度ポリエチレン樹脂固型容器を予め用意し、外側よりＨＤＰＥ（高密度ポリエチレン）フィルム３０μｍ／ウレタン系ドライ接着剤４μｍ／アルミニウム箔（Ａｌ純度９９．３重量％軟質材）３０μｍ／ウレタン系ドライ接着剤４μｍ／ＨＤＰＥフィルム３０μｍの順で積層してなる防湿シートを樹脂固型容器の外底面および外側面に個別に、重ね合わせて熱接着（実施例１と同様）することにより蓄電用容器を得た。なお、樹脂固型容器の外底面に熱接着した防湿シートおよび樹脂固型容器の外側面に熱接着した防湿シートは、いずれも幅２ｍｍの継ぎ代部を設けた。なお、試験用蓋材としてはＯＰニス１〜２μｍ／アルミニウム箔（Ａｌ純度９９．３重量％軟質材）２０μｍ／ウレタン系ドライ接着剤３〜４μｍ／ナイロンフィルム１５μｍ／ウレタン系ドライ接着剤３〜４μｍ／ＬＬＤＰＥ（線状低密度ポリエチレン）フィルム４０μｍを用い、後述の電解液等を充填後、容器開口部に熱板シール（温度：１８０℃、時間：３ｓｅｃ、圧力：３ｋｇ／ｃｍ^２、シール幅：容器の肉厚）した。
【００４３】
（実施例４）実施例３の蓄電用容器を６つ用い、これを開口方向を揃えて射出成形用の金型内に並べ、次いでこれらの蓄電用容器の防湿シートを有する面と金型との間に形成されたキャビティに溶融された高密度ポリエチレン樹脂を射出することにより、肉厚２ｍｍの結束体を成形すると同時に該結束体により蓄電用容器を束ね、蓄電用容器集合体を得た。
【００４４】
（比較例１）実施例１でアルミ貼りしないポリプロピレン単体の成型容器を用いる以外は実施例１と同じ蓋材を用い同様な評価を行った。
【００４５】
（比較例２）実施例３でアルミ貼りしない高密度ポリエチレン単体の成型容器を用いる以外は実施例３と同じ蓋材を用い同様な評価を行った。
【００４６】
以下に、実施例１および３、比較例１および２での防水特性、及びリチウムイオン電池、有機系電気２重層コンデンサ−用の電解液に対する耐性の評価結果を示す。
【００４７】
テストＡ：容器内に塩化カルシウムを約８０ｇ充填し、試験用蓋材を容器開口部に熱板シール後、高温多湿雰囲気中（４０℃×９０％×２０日）で経時させ重量増加分を水分透過量とした。テストＢ：電気２重層用電解液（プロピレンカーボネートに、テトラエチルアンモニウムテトラフルオロホウ素（（Ｃ_２Ｈ_５）_４ＮＢＦ_４）１ｍｏｌ添加）を約１００ｇ充填し、試験用蓋材を容器開口部に熱板シール後、高温多湿雰囲気中（４０℃×９０％×２０日）で経時させ電解液の変色及び内層材料の変化を調べた。テストＣ：リチウムイオン電池用電解液（ＥＣ／ＤＥＣ＝１／１のモル比の溶剤にＬｉＰＦ_６を１ｍｏｌ添加）を約１００ｇ充填し、試験用蓋材を容器開口部に熱板シール後、高温多湿雰囲気中（４０℃×９０％×２０日）で経時させ電解液の変色及び内層材料の変化を調べた。
【００４８】
【表１】

【００４９】
【発明の効果】
本発明の蓄電用容器、蓄電用容器集合体及びこれらの製造方法は、前記した構成及び作用からなるので、次の効果が奏される。
【００５０】
すなわち、材料が樹脂とアルミニウム箔とからなるため、さらなる軽量化を図ることができる。
【００５１】
また、上記しているように上部に蓋をする際には、嵌合、接着剤による接着、ヒートシール、圧入又は螺合すれば済み、従来技術のように溶接は不要である。そのため、上記蓄電用容器および蓄電用容器集合体は、蓋をする際の量産性に優れる。
【００５２】
また、蓄電用容器および蓄電用容器集合体の最も内側は樹脂材料からなるため絶縁性を有し、端子部の絶縁性を図るために複雑な部材設計の必要性がなく、電池容器と端子部のショ−トという問題は生じない。
【図面の簡単な説明】
【図１】本発明に係る蓄電用容器の一実施例を示す斜視図である。
【図２】本発明に係る蓄電用容器に用いる樹脂固型容器の一実施例を示す部分断面斜視図である。
【図３】本発明に係る蓄電用容器に用いる防湿シートの一実施例を示す断面図である。
【図４】本発明に係る蓄電用容器の他の実施例を示す断面図である。
【図５】本発明に係る蓄電用容器の製造方法の一実施例を示す断面図である。
【図６】本発明に係る蓄電用容器の製造方法の他の実施例を示す図である。
【図７】本発明に係る蓄電用容器集合体の一実施例を示す斜視図である。
【図８】本発明に係る蓄電用容器集合体の他の実施例を示す斜視図である。
【符号の説明】
１蓄電用容器
２樹脂固型容器
２ａ外側面
２ｂ外底面
３防湿シート
３ａ継ぎ代部
４蓄電用容器集合体
５防蝕性樹脂層
６アルミニウム箔
７熱接着性樹脂層
８結束体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power storage container, a power storage container assembly excellent in weight reduction, mass productivity at the time of covering, and excellent terminal insulation, and a method of manufacturing these.
[0002]
[Prior art]
Non-Patent Document 1 discloses that an aluminum alloy sheet material has been newly developed for use in a lithium ion secondary battery case, and that element mixing and rolling techniques for improving only strength while maintaining weldability have been established. . Lithium-ion rechargeable batteries are small, high-voltage and suitable for repeated charging, so they are mainly used as batteries for mobile phones, notebook computers, etc., and their use is expected to expand in the future. is there. Attention has also been focused on batteries for hybrid cars, electric vehicles, fuel cell vehicles, and the like. Conventionally, a steel plate material has been mainly used as a case (material of an outer can) of such a lithium ion secondary battery. However, in recent years, the need to reduce the weight has been rapidly changing to an aluminum plate material. The aluminum plate material for the case is required to have high formability and weldability (to cover the upper part and weld), and also to have high swelling resistance to withstand the pressure increase inside the battery. Further, the case is becoming thinner due to the miniaturization of the battery, and the strength requirement for the aluminum plate material is increasing every year. In order to meet these needs, the above-mentioned new aluminum alloy sheet material improves the conventional "JISA3003P (Al-Mn alloy)" to improve the strength and at the same time, aims to prevent cracking during welding. While improving the tensile strength by 15 to 20% while maintaining the same level of weldability and formability as the alloy.
[0003]
[Non-patent document 1]
Public Relations & IR Office, “Focus on expanding sales of aluminum plates for lithium-ion secondary battery cases”, [online], November 13, 2002, Nippon Light Metal Co., Ltd., Nikkikin Group News, [Search December 18, 2002] ], Internet <URL: http: // www. nikkikin. co. jp / pages / press / P2002 / p20021113. htm>
[0004]
[Problems to be solved by the invention]
However, the case of the above-mentioned lithium ion secondary battery is not limited to being made of metal even if it is made of an aluminum plate, and there is a limit to weight reduction. In particular, in applications such as a hybrid car, an electric vehicle, and a fuel cell vehicle, the size of the battery is increased, so that the above-described problem becomes more remarkable.
[0005]
In addition, as described above, welding is required to cover the upper part. However, aluminum is difficult to locally heat due to its high thermal conductivity. Cost. In terms of characteristics, since volume shrinkage and linear expansion coefficient during solidification are large, welding distortion is likely to occur, and cracks may occur depending on the alloy. Further, since a strong oxide film is present on the surface, a large amount of flux is required, and crystallization water coexisting in the oxide film causes welding defects such as blowholes in a welded portion. Furthermore, since it is a chemically active metal, it is necessary to protect the surface with an inert gas or the like. For this reason, inert gas arc welding (TIG welding / MIG welding) is frequently used, but this method is not suitable for mass production because a large amount of inert gas and expensive tungsten electrodes or consumable electrodes are required. The pressure welding method uses a high pressure and can be used for a thick plate, but is not suitable for a thin aluminum plate (foil). In addition, electron beam welding, plasma welding, and the like are conceivable, but many of them are still under development and are not widely used industrially because the equipment is expensive. Therefore, including a welding step is not suitable for mass production.
[0006]
In addition, since the entire case is made of a conductive material, an insulating member such as insulating ceramics, insulating resin or rubber must be engaged or screwed around the terminal portion in order to achieve insulation of the terminal portion. However, there is always a risk that the terminal section and the case may be short-circuited (short-circuited) due to adhesion of moisture or careless work. In order to completely prevent a short circuit, the entire case must be covered with an insulating material, which is disadvantageous in terms of cost and mass productivity.
[0007]
Therefore, an object of the present invention is to solve the above-mentioned problems, to reduce the weight, to mass-produce when closing the lid, and to provide a case for a battery or a capacitor other than a lithium ion secondary battery, which is excellent in the insulation of the terminals. Another object of the present invention is to provide a power storage container, a power storage container assembly, and a method for manufacturing the same.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the electricity storage container of the present invention comprises a cylindrical resin solid container having electrolytic resistance, and a moisture-proof sheet covering the outer surface of the resin solid container, and the moisture-proof sheet Is formed by laminating at least a corrosion-resistant resin layer and an aluminum foil in this order from the outside.
[0009]
Further, in the method for manufacturing a power storage container of the present invention, the moisture-proof sheet formed by laminating at least the corrosion-resistant resin layer and the aluminum foil in this order from the mold side is disposed on the inner wall of the injection-molding mold. Then, a resin having electrolytic solution resistance was injection-molded in the cavity to obtain a cylindrical resin solid container, and the outer surface of the resin solid container was covered with a moisture-proof sheet.
[0010]
Further, the method for producing a power storage container of the present invention includes preparing a tubular resin solid container having electrolytic solution resistance in advance, and forming an outer surface of the resin solid container at least from the outside to the corrosion-resistant resin layer, aluminum. Moisture-proof sheets laminated in the order of foil were overlapped and bonded to cover.
[0011]
Further, in each of the above-described configurations, the resin solid container is cylindrical with a bottom, and the outer bottom surface and the outer surface of the resin solid container are covered with a moisture-proof sheet.
[0012]
Furthermore, in the method for manufacturing a power storage container of the present invention, a moisture-proof sheet formed by laminating at least a corrosion-resistant resin layer and an aluminum foil in this order from the mold side is disposed on the inner wall of a blow molding mold. Then, a resin having electrolytic solution resistance is blow-molded in the cavity to obtain a bottomed cylindrical resin solid container, and at the same time, cover the outer bottom surface and the outer surface of the resin solid container with a moisture-proof sheet. It was configured as follows.
[0013]
In each configuration in which the outer bottom surface is also covered with the moisture-proof sheet, the moisture-proof sheet covering the outer bottom surface of the resin-solid-type container and the moisture-proof sheet covering the outer surface of the resin-solid-type container are configured separately.
[0014]
In each of the above-described configurations, the moisture-proof sheet is configured such that a heat-adhesive resin layer is laminated on the resin-solid container side of the aluminum foil.
[0015]
In addition, the power storage container assembly of the present invention is configured such that the power storage containers are arranged in plural with their opening directions aligned, and are bound by a binding body.
[0016]
In addition, the method for manufacturing a power storage container assembly of the present invention uses a plurality of the power storage containers, arranges them in an injection molding mold with the opening directions aligned, and then prepares a moisture-proof sheet for these power storage containers. By injecting the melted resin into a cavity formed between the surface and the mold, the binding body is formed and the storage container is bound by the binding body.
[0017]
The above-described power storage container and power storage container assembly have the following features that cannot be obtained with a container made of a conventional aluminum plate due to their configurations. That is, since the material is made of the resin and the aluminum foil, further weight reduction can be achieved.
[0018]
Further, when the lid is put on the upper part as described above, fitting, bonding with an adhesive, heat sealing, press-fitting, screwing, etc. may be performed, and welding as in the related art is unnecessary. Therefore, the power storage container and the power storage container assembly are excellent in mass productivity when the lid is closed.
[0019]
Further, since the innermost part of the power storage container is made of a resin material, it has an insulating property, and there is no need to design a complicated member for achieving the insulating property of the terminal part. Does not occur.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a power storage container, a power storage container assembly, and a method for manufacturing the same will be described in detail with reference to the drawings.
[0021]
A storage container 1 shown in FIG. 1 has a bottomed cylindrical resin solid container 2 (see FIG. 2) having an electrolytic solution resistance, and a moisture proof covering the outer bottom surface 2 b and the outer surface 2 a of the resin solid container 2. The moisture-proof sheet 3 is formed by laminating the corrosion-resistant resin layer 5, the aluminum foil 6, and the heat-adhesive resin layer 7 in this order from the outside (see FIG. 3). Further, the moisture-proof sheet 3 that covers the outer bottom surface 2b of the resin solid container and the moisture-proof sheet that covers the outer surface 2a of the resin solid container 2 are separate bodies.
[0022]
The resin solid container 2 is for imparting the shape and strength as a container to the power storage container 1. The resin solid container 2 is preferably formed by injection molding or blow molding for the following reasons. Injection molding is a method in which a resin material is heated to a fluidized state, injected into a cavity (cavity) of a closed mold under pressure, and solidified in the mold, thereby forming a shape corresponding to the mold cavity. It is a method of building. In blow molding, a cylindrical resin called a parison in a molten state is extruded from a die, the mold is closed, and then pressurized gas is blown into the closed parison to expand the parison to the full inside of the mold and to form a hollow. This is a molding method for making products. Therefore, the molded article obtained by these methods has a wide range of choices in shape, and has high blister resistance, which can withstand a pressure increase inside the battery, similarly to a container made of a conventional aluminum plate.
[0023]
The resin solid container 2 is used as a power storage container assembly 4 in which a plurality of power storage containers 1 are arranged in the same opening direction as described later and are bound by a binding body. It is formed into a bottomed cylindrical shape with a large direction so that its capacity is 50 cc or more. Further, in order to cover the outer bottom surface 2b and the outer side surface 2a of the resin solid container 2 with the moisture-proof sheet 3, the shape of this tube is preferably a cylinder or a square tube as shown in FIG. 1 (see FIG. 4). The inner wall surface of the cylinder or the square tube may have a taper so that the opening becomes wider. The thicknesses of the resin solid container 2 and the power storage container assembly 4 are not particularly limited, but are preferably 0.5 to 10 mm from the viewpoint of material strength, swelling resistance, and installation space.
[0024]
As the material of the resin solid container 2, a material having resistance to electrolyte, gas barrier property, heat resistance, and processability is used. For example, polyolefin resins such as polyethylene / polypropylene / TPX, polyester resins such as PET / PEN / PBT, acrylic resins such as PMMA / BMA / EMA, styrene resins such as ABS / styrene / AS, vinyl chloride / vinyl acetate / salt Simple substances such as vinyl acetate copolymer resin, vinyl acetate vinyl acetate copolymer resin, vinyl resin such as ethylene vinyl alcohol, polyamide resin such as nylon 6 and nylon 66, fluorine resin and silicone resin, and composites thereof can be used. Of these, polyolefin resins, particularly polypropylene resins, are desirable because they are excellent in the above-mentioned electrolytic solution resistance, gas barrier properties, heat resistance, and workability.
[0025]
The aluminum foil 6 used for the moisture-proof sheet 3 is a gas barrier layer for preventing water vapor gas or oxygen gas from entering the power storage container 1 from the outside. Considering securing of gas barrier properties, workability, and the like, Its thickness is preferably in the range of 6 to 200 μm. If the thickness of the aluminum foil 6 is less than 6 μm, the occurrence of pinholes becomes extremely large, and the gas barrier property is reduced. On the other hand, if the thickness of the aluminum foil 6 exceeds 200 μm, heat easily escapes and the weight increases, which is not economically desirable. The components of the aluminum foil are not particularly limited, and known pure aluminum or aluminum alloy can be used. The refining may be any of hard, semi-hard, soft, and the like, and may be appropriately selected. The aluminum foil may be subjected to degreasing / washing, anchor coating, primer coating, surface treatment (chromic acid treatment, etc.) by a known method, if necessary.
[0026]
The corrosion-resistant resin layer 5 laminated on the outer side of the aluminum foil 6 prevents the aluminum foil 6 from being cracked, perforated, peeled, broken, etc. due to mechanical contact with other articles. It is provided for the purpose of preventing corrosion of the aluminum foil 6 due to adhesion of an electrolytic solution or the like. Materials used for the corrosion-resistant resin layer 5 include polyethylene (HDPE, LDPE, LLDPE, etc.), polyester (PET, PEN, PBT, etc.), polypropylene (stretched PP, unstretched PP), polyamide (nylon, MXD nylon) Etc.), polyvinylidene chloride, vinyl chloride, fluorine-based, ethylene-vinyl alcohol copolymer, polycarbonate and other resin films, or epoxy resin, acrylic resin, polyester resin, polyolefin resin, fluorine resin-based anticorrosion coating agent. Can be used. In particular, polyethylene (HDPE), polyester (PET), and polypropylene (stretched PP, unstretched PP) are used for films in terms of the total balance of flexibility, cost, strength, and the like, and baking type epoxy is used as a coating agent. Resins and acrylic resins are preferred in terms of corrosion resistance and cost. The thickness of the film used for the anticorrosive resin layer 5 is preferably in the range of 12 to 80 μm, and the thickness of the coating agent is preferably 2 to 30 μm. If the thickness of the film is less than 12 μm, pinholes will be generated more frequently, lamination will be difficult, and wrinkles will be generated. On the other hand, when the thickness exceeds 80 μm, it causes an increase in cost and poor thermal bonding. When the thickness of the resin coat layer is 2 μm or less, the corrosion resistance is not sufficient. When the thickness is 30 μm or more, not only the coating and drying becomes difficult but also the cost is not preferable.
[0027]
In addition, as a method of laminating the corrosion-resistant resin layer 5 in the form of a film on the aluminum foil 6, the lamination can be performed by a known dry lamination method using a known adhesive for dry lamination. Further, as a lamination method, extrusion lamination, wet lamination, heat lamination, or the like can also be employed.
[0028]
Moreover, in the moisture-proof sheet 3 of the present invention, it is sufficient that at least the corrosion-resistant resin layer and the aluminum foil are laminated in this order from the outside, but as shown in FIG. It is preferable that the adhesive resin layer 7 is laminated. The reason is that the moisture-proof sheet 3 can be firmly fixed to the resin solid container 2 by thermally bonding the heat adhesive resin layer 7 and the resin solid container 2. If the adhesive strength is weak, there is a risk that the adhesive will peel off or air (moisture) will enter. Examples of the material used for the heat-adhesive resin layer 7 include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear linear polyethylene, saturated polyester, linear saturated polyester, undrawn polypropylene, chlorinated polypropylene, and ethylene-acryl. Acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ionomer, ethylene-ethyl acrylate-maleic anhydride terpolymer, polyolefin, carboxylic acid Modified polyethylene, carboxylic acid-modified polypropylene, carboxylic acid-modified ethylene-vinyl acetate, vinyl chloride, polystyrene and the like can be mentioned. Commercial products such as "Bondane" manufactured by Sumitomo Chemical Co., Ltd. and "Mersen M" manufactured by Tosoh Corporation can also be used. These thermo-adhesive resins can be used in the form of a film or directly applied to the aluminum foil 6. Particularly, a similar resin material used for the resin container is preferable from the viewpoint of adhesiveness. The thickness of the heat-adhesive resin layer 7 is preferably in the range of 1 to 80 μm. If the thickness is less than 1 μm, the heat bonding strength may be insufficient. On the other hand, if the thickness exceeds 80 μm, moisture may be mixed from the end face, which is not preferable in terms of barrier properties.
[0029]
In addition, as a method of laminating the heat-adhesive resin layer 7 in the form of a film on the aluminum foil 6, the lamination can be performed by a well-known dry lamination method using a well-known dry laminating adhesive. In addition, as a lamination method, extrusion lamination, wet lamination, heat lamination, hot melt, or the like may be employed, or a lacquer-type thermal adhesive may be applied. In addition, a reinforcing resin film or the like can be interposed between the aluminum foil 6 and the heat-adhesive resin layer 7. As the reinforcing resin film, polyethylene (HDPE, LDPE, LLDPE, etc.) having a thickness of 9 to 50 μm, polyester System (PET, PEN, PBT, etc.), polypropylene (stretched PP, non-stretched PP), polyamide (nylon, MXD nylon, etc.), polyvinylidene chloride, vinyl chloride, fluorine, ethylene-vinyl alcohol copolymer, polycarbonate, etc. Can be interposed.
[0030]
In addition, although the reasons for the individual thicknesses of the respective layers have been described above, the thickness of the entire moisture-proof sheet 3 is preferably in the range of 40 to 300 μm. If the total thickness is less than 40 μm, the moisture-proof sheet 3 has no rigidity, so that it is difficult to cover the resin solid container 2. On the other hand, if the total thickness exceeds 300 μm, it causes a decrease in flexibility, an increase in cost, poor thermal bonding, and poor adhesion. In addition, other than the above-described layers, if necessary, a printing layer, a coloring layer, a cushion layer, an overcoat layer, an adhesion reinforcing layer, and the like may be interposed or laminated. Additives and auxiliaries such as agents and ultraviolet absorbers.
[0031]
The power storage container 1 of the present invention as described above is manufactured by covering the resin solid container 2 with the moisture-proof sheet 3 by the following method.
[0032]
That is, the moisture-proof sheet 3 formed by laminating at least the corrosion-resistant resin layer 5 and the aluminum foil 6 in this order from the side of the mold 9 is disposed on the inner wall of the mold 9 for injection molding (see FIG. 5). Next, the molten resin having the electrolytic solution resistance is injected into the cavity to obtain the resin solid container 2 formed into a bottomed cylindrical shape, and at the same time, the outer bottom surface 2b and the outer surface of the resin solid container 2 2 a is covered with a moisture-proof sheet 3. Further, the resin solid container 2 may be obtained by blow molding, and may be covered with the moisture-proof sheet 3 at the same time.
[0033]
Further, a bottomed cylindrical resin solid container 2 having electrolytic solution resistance is prepared in advance, and at least an anticorrosive resin layer 5 and an aluminum foil are formed on the outer bottom surface 2b and the outer surface 2a of the resin solid container 2 from the outside. The moisture-proof sheets 3 laminated in the order of No. 6 can be overlapped and bonded (see FIG. 6). When the moisture-proof sheet 3 covering the outer bottom surface 2b of the resin solid container 2 and the moisture-proof sheet 3 covering the outer surface 2a of the resin solid container 2 are separate bodies, this method is better than the method using the mold 9 described above. More preferred. This is because inserting the plurality of moisture-proof sheets 3 into the mold 9 and holding the moisture-proof sheets 3 along the inner wall of the mold 9 is troublesome. In addition, when the heat-adhesive resin layer 7 is provided on the moisture-proof sheet 3 and the resin-solid container 2 prepared in advance and the heat-adhesive resin layer 7 are heat-bonded to each other, the means may be an external heating or an internal heating. There is. As a heat bonding method by external heating, there is a pressure bonding method in which heat pressure is applied from the outside of the moisture-proof sheet 3 using a heat transfer machine with a heat roller, an up-down transfer machine, or the like. As a thermal bonding method by internal heating, an interface to be bonded, that is, the outer side surface 2a and the outer bottom surface 2b of the resin solid container 2 and the heat bonding resin layer 7 of the moisture-proof sheet 3 are brought into close contact with each other. There is a welder processing method that generates heat by vibrating the interface by applying ultrasonic or high frequency
[0034]
In the heat bonding step, it is also possible to cut out the moisture-proof sheet 3 into a predetermined shape one by one and heat-bond it to the resin solid container 2. It is stuck on a long auxiliary sheet at regular intervals to form a roll. This is automatically fed out, and only the moisture-proof sheet 3 cut by applying heat and pressure from the auxiliary sheet side is thermally bonded to the resin solid container 2. Alternatively, a method of winding the auxiliary sheet (a so-called transfer lamination method) can be employed.
[0035]
5 and 6, the moisture-proof sheet 3 that covers the outer bottom surface 2b of the resin-molded container 2 and the moisture-proof sheet 3 that covers the outer surface 2a of the resin-molded container 2 are separate bodies. Although the first manufacturing method is described, the present invention covers the resin solid container 2 by using a single moisture-proof sheet 3 formed by deep drawing according to the shape of the resin solid container 2. It does not matter. However, when the moisture-proof sheet 3 covering the outer bottom surface 2b of the resin solid container 2 and the moisture-proof sheet 3 covering the outer surface 2a of the resin solid container 2 are separate bodies, even if the aluminum foil 6 is thin, it is relatively large. Has the effect that the aluminum foil 6 has a uniform thickness over the entire container and there is little danger of generation of pinholes or the like into which steam gas enters during processing. If there is a gap at the boundary between the outer surface 2a and the outer bottom surface 2b, gas barrier properties are impaired. Therefore, one end of the moisture-proof sheet 3 covering the outer surface 2a or the moisture-proof sheet 3 covering the outer bottom surface 2b faces the boundary. It is preferable that the portion is a joint portion 3a, and the other moisture-proof sheet 3 is double overlapped with the end facing the boundary (see FIG. 6). In addition, for the moisture-proof sheet 3 covering the outer surface 2a, if there is a gap between the end of the winding of the resin solid container 2 on the outer surface 2a and the end of the winding, the gas barrier property is impaired. It is preferable to provide a portion where both ends are double overlapped (joining portion 3a) (see FIG. 6). When the joint portion 3a is provided, the inner and outer layers of the moisture-proof sheet 3 that are in contact with each other are selected to be hard to peel.
[0036]
The power storage container 1 of the present invention having the above-described configuration is used as a power storage container assembly 4 by arranging a plurality of the power storage containers 1 with their opening directions aligned and bundling them with a binding body 8 (see FIGS. 7 and 8). ). In FIGS. 7 and 8, three power storage containers 1 are used to form power storage container assembly 4. However, the number of power storage containers 1 constituting power storage container assembly 4 of the present invention is two. Alternatively, the number may be four or more.
[0037]
The binding body 8 is for securing the installation stability, the handling property, and the mass productivity. As an aspect, for example, a plurality of power storage containers 1 are aligned in the opening direction and are placed in an injection molding die. Then, the molten resin is injected into a cavity formed between the surface of the power storage container 1 having the moisture-proof sheet 3 and the mold, thereby forming the binding body 8 and simultaneously forming the binding body 8. Thus, the power storage containers 1 can be bundled. In this case, the power storage containers 1 may be contacted and bundled as shown in FIG. 7, or the power storage containers 1 may be bundled without contacting each other as shown in FIG. In addition, the binding body 8 made of the injection molded article does not have to cover the bottom surface of the power storage container 1 and may cover only a part of the side surface of the power storage container 1.
[0038]
Examples of the material of the binding body 8 made of the injection molded article include polypropylene, polyethylene, methyl methacrylic resin, acryl-styrene copolymer resin, polystyrene, ABS, vinyl chloride, polyamide, polycarbonate, polyacetal, and tetrafluoride resin. Can be used.
[0039]
Further, as another mode of the binding body 8, a binding or binding with rubber, an elastomer, or the like, a binding with a resin-coated metal wire (or plate), a wrapping with a heat-shrinkable film, or the like can be performed.
[0040]
【Example】
(Example 1) A polypropylene resin solid container formed by injection molding into a bottomed cylindrical shape having an inner diameter of 40 mm, a thickness of 4 mm, and a length of 140 mm is prepared in advance, and a CPP (unstretched polypropylene) film 30 µm / urethane-based dry from the outside. Adhesive 4 μm / aluminum foil (Al purity 99.3% by weight soft material) 30 μm / urethane dry adhesive 4 μm / CPP film A moisture-proof sheet laminated in the order of 30 μm is provided on the outer bottom surface and the outer surface of the resin solid container. Individually, overlapping and heat bonding (temperature: 200 ° C, time: 3 sec, pressure: 3 kg / cm ² ) To obtain a power storage container. Each of the moisture-proof sheet thermally bonded to the outer bottom surface of the resin solid container and the moisture-proof sheet thermally bonded to the outer surface of the resin solid container was provided with a 2 mm-width joint portion. In addition, OP varnish 1 to 2 μm / aluminum foil (Al purity: 99.3% by weight soft material) 40 μm / urethane-based dry adhesive 3 to 4 μm / CPP film 40 μm was used as a test lid material. After filling, seal the hot plate at the container opening (temperature: 200 ° C, time: 3 sec, pressure: 3 kg / cm ² , Seal width: thickness of the container).
[0041]
(Example 2) Six power storage containers of Example 1 were used, and they were arranged in an injection-molding mold with their opening directions aligned. Then, the surfaces of the power storage containers having a moisture-proof sheet and the die were used. By injecting the melted polypropylene resin into the cavity formed between them, a binding body having a thickness of 2 mm was formed, and at the same time, the storage containers were bundled with the binding body to obtain a storage container assembly.
[0042]
(Example 3) A high-density polyethylene resin solid container formed by injection molding into a square cylinder with a bottom having a mouth size of 20 mm x 50 mm, a thickness of 1 mm, and a length of 140 mm is prepared in advance, and HDPE (high-density polyethylene) is provided from the outside. A moisture-proof sheet formed by laminating a film 30 μm / urethane-based dry adhesive 4 μm / aluminum foil (Al-purity 99.3% by weight soft material) 30 μm / urethane-based dry adhesive 4 μm / HDPE film 30 μm in this order is a resin solid container. A power storage container was obtained by individually superimposing and thermally bonding the outer bottom surface and the outer side surface (as in Example 1). Each of the moisture-proof sheet thermally bonded to the outer bottom surface of the resin solid container and the moisture-proof sheet thermally bonded to the outer surface of the resin solid container was provided with a 2 mm-width joint portion. The test lid material is OP varnish 1 to 2 μm / aluminum foil (softness of Al purity 99.3% by weight) 20 μm / urethane dry adhesive 3 to 4 μm / nylon film 15 μm / urethane dry adhesive 3 to 4 μm / LLDPE (linear low-density polyethylene) film 40 μm, and after filling with an electrolytic solution and the like described below, a hot plate seal (temperature: 180 ° C., time: 3 sec, pressure: 3 kg / cm) ² , Seal width: thickness of the container).
[0043]
(Example 4) Six power storage containers of Example 3 were used, and they were arranged in a mold for injection molding with their opening directions aligned. Then, the surfaces of these power storage containers having a moisture-proof sheet and a die were used. By injecting the melted high-density polyethylene resin into the cavity formed between them, a 2 mm-thick bound body was formed, and at the same time, the power storage containers were bundled with the bound body to obtain a power storage container aggregate.
[0044]
(Comparative Example 1) The same evaluation was performed using the same lid material as in Example 1 except that a molded container of polypropylene alone which was not bonded to aluminum in Example 1 was used.
[0045]
(Comparative Example 2) The same evaluation was performed using the same lid material as in Example 3, except that a molded container of high-density polyethylene alone not bonded to aluminum was used in Example 3.
[0046]
The evaluation results of the waterproof properties in Examples 1 and 3 and Comparative Examples 1 and 2 and the resistance to the electrolyte for lithium ion batteries and organic electric double layer capacitors are shown below.
[0047]
Test A: Approximately 80 g of calcium chloride was filled in a container, and a lid for testing was sealed with a hot plate at the opening of the container. Then, the container was aged in a high-temperature and high-humidity atmosphere (40 ° C. × 90% × 20 days) to remove the weight increase. The transmission amount was used. Test B: Electrolytic solution for electric double layer (propylene carbonate, tetraethylammonium tetrafluoroboron ((C ₂ H ₅ ) ₄ NBF ₄ ) (1 mol added) was filled in about 100 g, the test lid material was sealed on the opening of the container with a hot plate, and then allowed to age in a high-temperature and high-humidity atmosphere (40 ° C. × 90% × 20 days). Was examined. Test C: Lithium ion battery electrolyte (EC / DEC = 1/1 molar ratio solvent LiPF ₆ (1 mol added), and the test lid was sealed on the opening of the container with a hot plate, and then allowed to age in a high-temperature and high-humidity atmosphere (40 ° C. × 90% × 20 days) to change the color of the electrolytic solution and the change of the inner layer material. Was examined.
[0048]
[Table 1]

[0049]
【The invention's effect】
Since the power storage container, the power storage container assembly, and the method of manufacturing the same according to the present invention have the above-described configuration and operation, the following effects can be obtained.
[0050]
That is, since the material is made of the resin and the aluminum foil, further weight reduction can be achieved.
[0051]
In addition, when the lid is put on the upper part as described above, fitting, bonding with an adhesive, heat sealing, press-fitting or screwing is sufficient, and welding as in the prior art is unnecessary. Therefore, the power storage container and the power storage container assembly are excellent in mass productivity when the lid is closed.
[0052]
In addition, since the innermost part of the power storage container and the power storage container assembly is made of a resin material, it has an insulating property, and there is no need to design a complicated member for achieving the insulating property of the terminal part. No short-circuit problem occurs.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a power storage container according to the present invention.
FIG. 2 is a partial cross-sectional perspective view showing one embodiment of a resin solid container used for the power storage container according to the present invention.
FIG. 3 is a cross-sectional view showing one embodiment of a moisture-proof sheet used for a power storage container according to the present invention.
FIG. 4 is a sectional view showing another embodiment of the power storage container according to the present invention.
FIG. 5 is a cross-sectional view showing one embodiment of the method for manufacturing a power storage container according to the present invention.
FIG. 6 is a view showing another embodiment of the method for manufacturing a power storage container according to the present invention.
FIG. 7 is a perspective view showing an embodiment of the power storage container assembly according to the present invention.
FIG. 8 is a perspective view showing another embodiment of the power storage container assembly according to the present invention.
[Explanation of symbols]
1 storage container
2 Resin solid container
2a Outside surface
2b Outer bottom
3 Moisture proof sheet
3a Joint section
4 Storage container assembly
5 Corrosion-resistant resin layer
6 Aluminum foil
7 Thermal adhesive resin layer
8 unity

Claims

It is composed of a cylindrical resin solid container having an electrolytic solution resistance, and a moisture-proof sheet covering the outer surface of the resin solid container, and the moisture-proof sheet is laminated at least from the outside in the order of a corrosion-resistant resin layer and an aluminum foil. A power storage container characterized by comprising:

The power storage container according to claim 1, wherein the resin solid container has a bottomed cylindrical shape, and the moisture-proof sheet covers an outer bottom surface and an outer surface of the resin solid container.

3. The power storage container according to claim 2, wherein the moisture-proof sheet covering the outer bottom surface of the resin solid container and the moisture-proof sheet covering the outer surface of the resin solid container are separate bodies.

The power storage container according to any one of claims 1 to 3, wherein the moisture-proof sheet is formed by laminating a heat-adhesive resin layer on a resin solid container side of the aluminum foil.

On the inner wall of the mold for injection molding, a moisture-proof sheet formed by laminating at least a corrosion-resistant resin layer and an aluminum foil in this order from the mold side is arranged, and then a resin having electrolytic solution resistance in the cavity. A method for producing a power storage container, characterized in that a cylindrical resin-type solid container is obtained by injection-molding, and the outer surface of the resin-type solid container is covered with a moisture-proof sheet.

A tubular resin solid container having electrolytic resistance is prepared in advance, and a moisture-proof sheet formed by laminating the outer surface of the resin solid container at least from the outside in the order of at least a corrosion-resistant resin layer and an aluminum foil. A method for manufacturing a power storage container, wherein the power storage container is covered by bonding.

The method for manufacturing a power storage container according to claim 5, wherein the resin solid container has a cylindrical shape with a bottom, and an outer bottom surface and an outer surface of the resin solid container are covered with a moisture-proof sheet.

On the inner wall of the mold for blow molding, a moisture-proof sheet formed by laminating at least a corrosion-resistant resin layer and an aluminum foil in this order from the mold side is arranged, and then a resin having electrolytic solution resistance in the cavity. A method for producing a power storage container, characterized in that a bottomed cylindrical resin-type solid container is obtained by blow-molding, and the outer bottom surface and the outer surface of the resin-solid type container are covered with a moisture-proof sheet.

9. The method for manufacturing a power storage container according to claim 7, wherein the moisture-proof sheet covering the outer bottom surface of the resin solid container and the moisture-proof sheet covering the outer surface of the resin solid container are separate bodies. 10.

The method for manufacturing a power storage container according to any one of claims 5 to 9, wherein the moisture-proof sheet is formed by laminating a heat-adhesive resin layer on a resin-solid container side of an aluminum foil.

A power storage container assembly, wherein a plurality of the power storage containers according to any one of claims 1 to 4 are arranged in an aligned opening direction and bound by a binding body.

A plurality of power storage containers according to any one of claims 1 to 4, which are arranged in a mold for injection molding with their opening directions aligned, and then the surfaces of these power storage containers having a moisture-proof sheet and a die. A method for manufacturing a power storage container assembly, comprising: forming a binding body by simultaneously injecting a molten resin into a cavity formed between the power storage container and the power supply container;