JP3719235B2

JP3719235B2 - Thin battery, assembled battery, composite assembled battery and vehicle

Info

Publication number: JP3719235B2
Application number: JP2002198109A
Authority: JP
Inventors: 恭一渡邉
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2002-07-08
Filing date: 2002-07-08
Publication date: 2005-11-24
Anticipated expiration: 2022-07-08
Also published as: JP2004039577A

Description

【０００１】
【技術分野】
本発明は、封止手段の外周部の端縁から導出する端子を有する薄型電池に関し、特に印加される振動に対して強い構造を有する薄型電池に関する。
【０００２】
【背景技術】
封止手段の外周部の端縁から導出する端子を有する薄型電池の使用態様や使用条件の多様化に伴って、当該薄型電池に対して外部から印加される振動が増加する。この振動により、正極端子又は負極端子が電池外装部材から導出する部分（以下、単に端子導出部ともいう。）の剥離等により薄型電池内部に注入された電解液が漏洩し、当該薄型電池の性能低下を招く場合がある。
【０００３】
【発明の開示】
本発明は、印加される外力に対して強い構造を有する薄型電池を提供することを目的とする。
【０００４】
上記目的を達成するために、本発明によれば、２層の合成樹脂層に挟まれた１層の金属層を少なくとも有する２枚の外装部材の外周縁を融着して成る封止手段を備え、正極板、セパレータ、負極板、及び、電解質から成る発電要素を前記封止手段に封止すると共に、前記正極板に接続された正極端子及び前記負極板に接続された負極端子が前記封止手段の外周部の端縁から導出する薄型電池であって、前記外装部材の最内層に位置する第１の合成樹脂層が、前記外装部材の最外層に位置する第２の合成樹脂層のヤング率より小さいヤング率を有する薄型電池が提供される（請求項１参照）。
【０００５】
本発明では、電池外装部材が有する最内層の第１の合成樹脂層のヤング率を最外層の第２の合成樹脂層のヤング率より小さくなるように操作することにより、当該端子導出部の共振周波数を加振振動数から離遠させるように移行させ、共振を防止する。これにより、外部から印加される振動による端子導出部の剥離等の発生を著しく減少することが出来、印加される振動に対して強い構造を有する薄型電池とすることが可能となる。
【０００６】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。
第１実施形態
図１（Ａ）は本発明の第１実施形態に係る薄型電池の全体を示す平面図、図１（Ｂ）は（Ａ）のII−II線に沿う断面図である。図２は図１（Ａ）のIII部の拡大断面図である。図３は図２のマス-バネ系モデルである。図４は本発明の第１実施形態に係る端子導出部での振動伝達率スペクトルを示すグラフである。図１は一つの薄型電池（単位電池）を示し、この薄型電池１０を複数積層することにより所望の電圧、容量の組電池が構成される。
【０００７】
まず図１を参照しながら、本発明の第１実施形態に係る薄型電池１０の全体構成について説明すると、本例の薄型電池１０はリチウム系の薄型二次電池であり、２枚の正極板１０１と、５枚のセパレータ１０２と、２枚の負極板１０３と、正極端子１０４と、負極端子１０５と、上部電池外装部材１０６と、下部電池外装部材１０７と、特に図示しない電解質とから構成されている。このうちの正極板１０１，セパレータ１０２，負極板１０３および電解質を特に発電要素１０９と称する。
【０００８】
なお、正極板１０１，セパレータ１０２，負極板１０３の枚数には何ら限定されず、１枚の正極板１０１，３枚のセパレータ１０２，１枚の負極板１０４でも発電要素１０９を構成することができる。必要に応じて正極板、負極板およびセパレータの枚数を選択して構成することができる。
【０００９】
発電要素１０９を構成する正極板１０１は、金属酸化物などの正極活物質に、カーボンブラックなどの導電材と、ポリ四フッ化エンチレンの水性ディスパージョンなどの接着剤とを、重量比でたとえば１００：３：１０の割合で混合したものを、正極側集電体としてのアルミニウム箔などの金属箔の両面に塗着、乾燥させ、圧延したのち所定の大きさに切断したものである。なお、上記のポリ四フッ化エチレンの水性ディスパージョンの混合比率は、その固形分である。
【００１０】
正極活物質としては、例えばニッケル酸リチウム（ＬｉＮｉＯ_２）、マンガン酸リチウム（ＬｉＭｎＯ_２）、コバルト酸リチウム（ＬｉＣｏＯ_２）などのリチウム複合酸化物や、カルコゲン（Ｓ、Ｓｅ、Ｔｅ）化物を挙げることができる。これらの材質は薄型電池内部の発熱を比較的拡散し易く、端子への伝熱による端子の膨張による伸びを少なく出来、端子から後述する電池外装部材へ伝達する引張り応力を極力抑制することが可能となる。
【００１１】
発電要素１０９を構成する負極板１０３は、例えば非晶質炭素、難黒鉛化炭素、易黒鉛化炭素、または黒鉛などのように、正極活物質のリチウムイオンを吸蔵および放出する負極活物質に、有機物焼成体の前駆体材料としてのスチレンブタジエンゴム樹脂粉末の水性ディスパージョンをたとえば固形分比１００：５で混合し、乾燥させたのち粉砕することで、炭素粒子表面に炭化したスチレンブタジエンゴムを担持させたものを主材料とし、これに、アクリル樹脂エマルジョンなどの結着剤をたとえば重量比１００：５で混合し、この混合物を、負極側集電体としてのニッケル箔或いは銅箔などの金属箔の両面に塗着、乾燥させ、圧延したのち所定の大きさに切断したものである。
【００１２】
特に負極活物質として非晶質炭素や難黒鉛化炭素を用いると、充放電時における電位の平坦特性に乏しく放電量にともなって出力電圧も低下するので、通信機器や事務機器の電源には不向きであるが、電気自動車等の電源として用いると急激な出力低下がないので有利である。
【００１３】
また、発電要素１０９のセパレータ１０２は、上述した正極板１０１と負極板１０３との短絡を防止するもので、電解質を保持する機能を備えてもよい。セパレータ１０２は、例えばポリエチレン（ＰＥ）やポリプロピレン（ＰＰ）などのポリオレフィン等から構成される微多孔性膜であり、過電流が流れると、その発熱によって層の空孔が閉塞され電流を遮断する機能をも有する。
【００１４】
なお、本発明のセパレータ１０２は、ポリオレフィンなどの単層膜にのみ限られず、ポリプロピレン膜をポリエチレン膜でサンドイッチした三層構造や、ポリオレフィン微多孔膜と有機不織布などを積層したものも用いることができる。セパレータ１０２を複層化することで、過電流の防止機能、電解質保持機能およびセパレータの形状維持（剛性向上）機能などの諸機能を付与することができる。また、セパレータ１０２の代わりにゲル電解質又は真性ポリマー電解質等を用いることもできる。
【００１５】
以上の発電要素１０９は、上から正極板１０１と負極板１０３とが交互に、且つ当該正極板１０１と負極板１０３との間にセパレータ１０２が位置するような順序で積層され、さらに、その最上部及び最下部にセパレータ１０２が一枚ずつ積層されている。そして、２枚の正極板１０１のそれぞれは、正極側集電部１０４ａを介して、金属箔製の正極端子１０４に接続される一方で、２枚の負極板１０３は、負極側集電部１０５ａを介して、同じく金属箔製の負極端子１０５に接続されている。なお、正極端子１０４も負極端子１０５も電気化学的に安定した金属材料であれば特に限定されないが、正極端子１０４としてはアルミニウムやアルミニウム合金、銅又はニッケルなどを挙げることができ、負極端子１０５としてはニッケル、銅、ステンレス又は鉄などを挙げることができる。これらの金属は、金属の抵抗値、線膨張係数、抵抗率において薄型電池の構成要素として特に適当であり、使用温度を変えた場合にも、端子から後述する電池外装部材へ伝達する引張り応力を極力抑制することが可能となる。また、本例の正極側集電部１０４ａも負極側集電部１０５ａの何れも、正極板１０４および負極板１０５の集電体を構成するアルミニウム箔やニッケル箔、銅箔、鉄箔を延長して構成されているが、別途の材料や部品により当該集電部１０４ａ，１０５ａを構成することもできる。
【００１６】
発電要素１０９は、上部電池外装部材１０６及び下部電池外装部材１０７（封止手段）により封止されている。本発明の第１実施形態における上部電池外装部材１０６は、図２に示すように、薄型電池１０の内側から外側に向かって、第１の樹脂層１０６ａ、金属層１０６ｂ、第２の樹脂層１０６ｃの順で３つの層１０６ａ〜１０６ｃが積層される。この３つの層１０６ａ〜１０６ｃは、上部電池外装部材１０６の全面に渡って積層されており、第１の樹脂層１０６ａは、例えばポリエチレン、変性ポリエチレン、ポリプロピレン、変性ポリプロピレン、アイオノマーなどの耐電解液性及び熱融着性に優れた樹脂フィルムである。第２の樹脂層１０６ｃは、例えば、ポリアミド系樹脂、ポリエステル系樹脂等の電気絶縁性に優れた樹脂フィルムである。このように、電池外装部材の第１の樹脂層を、ポリプロピレン、変性ポリプロピレン、ポリエチレン、変性ポリエチレン、アイオノマーなどの樹脂で構成することにより、金属からなる正極端子又は負極端子と電池外装部材の第１の樹脂層との良好な融着性を確保することが可能となる。金属層１０６ｂは、例えば、アルミニウムなどの金属箔である。従って、上部電池外装部材１０６は、例えば、アルミニウムなどの金属箔の一方の面（薄型電池の内側面）をポリエチレン、変性ポリエチレン、ポリプロピレン、変性ポリプロピレン、アイオノマーなどの樹脂でラミネートし、他方の面（薄型電池の外側面）をポリアミド系樹脂、ポリエステル系樹脂等でラミネートした、樹脂−金属薄膜ラミネート材などの可撓性を有する材料で形成される。このように、電池外装部材が樹脂層に加えて金属層を具備することにより、電池外装部材の強度を向上させることが可能となる。なお、第２の樹脂層１０６ｃは、金属層１０６ｂの膜厚及び第１の樹脂層１０６ａの膜厚より相対的に薄い膜厚を有しており、第１の樹脂層１０６ａと金属層１０６ｂとによる後述する動吸振器的特性を効果的に作用させることが可能となる。
【００１７】
下部電池外装部材１０７は、上部電池外装部材１０６と同様の構造のものが用いられ、図２に示すように、薄型電池１０の内側から外側に向かって、第１の樹脂層１０７ａ、金属層１０７ｂ、第２の樹脂層１０７ｃの順で、３つの層１０７ａ〜１０７ｃが積層される。下部電池外装部材１０７の第１の樹脂層１０７ａは、上部電池外装部材１０６の第１の樹脂層１０６ａと同様に、例えばポリエチレン、変性ポリエチレン、ポリプロピレン、変性ポリプロピレン、アイオノマーなどの耐電解液性及び熱融着性に優れた樹脂フィルムである。下部電池外装部材１０７の金属層１０７ｂは、上部電池外装部材１０６の金属層１０６ｂと同様に、例えば、アルミニウムなどの金属箔である。下部電池外装部材１０７の第２の樹脂層１０７ｃは、上部電池外装部材１０６の第２の樹脂層１０６ｃと同様に、例えばポリアミド系樹脂、ポリエステル系樹脂等の電気絶縁性に優れた樹脂フィルムである。第２の樹脂層１０７ｃは、金属層１０７ｂの膜厚及び第１の樹脂層１０７ａの膜厚より相対的に薄い膜厚を有しており、第１の樹脂層１０７ａと金属層１０７ｂとによる後述する動吸振器的特性を効果的に作用させることが出来る。
【００１８】
さらに、これら正極端子１０４又は負極端子１０５と、電池外装部材１０６、１０７とから構成される端子導出部１１１は、当該端子導出部１１１の共振周波数を加振振動数から離遠させるように移行させ、当該端子導出部１１１における共振を防止するために、図３に示すような２自由度のマス-バネ系を構成している。図３のマス-バネ系モデルにおいて、薄型電池１０の正極端子１０４又は負極端子１０５が質量ｍ_１の第１のマス部Ｍに相当し、電池外装部材１０６、１０７の金属層１０６ｂ、１０７ｂが質量ｍ_２の第２のマス部Ｍａ、Ｍｂに相当する。また、上部電池外装部材１０６の第１の樹脂層１０６ａ及び下部電池外装部材１０７の第１の樹脂層１０７ａがヤング率ｋ_１の第１のバネ部Ｋ及び減衰要素Ｃに相当し、電池外装部材１０６、１０７の第２の樹脂層１０６ｃ、１０７ｃがヤング率ｋ_２の第２のバネ部Ｋａ、Ｋｂに相当し、第１のバネ部Ｋのヤング率ｋ_１は、第２のバネ部Ｋａ、Ｋｂのヤング率ｋ_２に対して５〜５５％の関係にある。このように、第２のバネ部Ｋａ、Ｋｂを第１のバネ部Ｋのヤング率ｋ_２より小さなヤング率ｋ_１とすることにより、第１のバネ部Ｋである第１の樹脂層１０６ａ、１０７ａと第２のマス部Ｍａ、Ｍｂである金属層１０６ｂ、１０７ｂとが動吸振器的に効果的に作用して、端子導出部１１１のマス-バネ系の共振周波数を加振振動数から離縁させるように移行させることが可能となる。なお、第１のバネ部Ｋのヤング率ｋ_１を第２のバネ部Ｋａ、Ｋｂのヤング率ｋ_２に対して５％未満にすると、第１のバネ部Ｋと第２のバネ部Ｋａ、Ｋｂとの動的バネ定数の差が過剰となり、端子導出部１１１の構造が弱くなる可能性がある。また、第１のバネ部Ｋのヤング率ｋ_１を第２のバネ部Ｋａ、Ｋｂのヤング率ｋ_２に対して５５％より大きくすると、ヤング率に依存する動的バネ定数の差が小さく、第２のマス部Ｍａ、Ｍｂ及び第１のバネ部Ｋによる動吸振器的な作用が弱まり、端子導出部１１１の共振周波数の移行が困難となる。
【００１９】
また、上述の正極端子１０４及び負極端子１０５は、電池外装部材１０６、１０７の金属層１０６ｂ、１０７ｂの膜厚の２〜５倍の厚さを有する。ここで、正極端子１０４及び負極端子１０５の厚さを金属層１０６ｂ、１０７ｂの膜厚の２倍未満とすると、当該金属層１０６ｂ、１０７ｂが端子導出部１１１の共振周波数に与える影響が大きくなり、当該端子導出部１１１の共振周波数の移行が困難となる可能性がある。また、正極端子１０４及び負極端子１０５の厚さを金属層１０６ｂ、１０７ｂの膜厚の５倍より大きくすると、金属層１０６ｂ、１０７ｂが端子導出部１１１の共振周波数に与える影響が小さくなり、必要とする振動数への移行が困難になる。
【００２０】
上述の２自由度のマス-バネ系における共振周波数（固有振動数）ω_１、ω_２は式１から実質的に算出することが可能である。
【００２１】
【式１】

本発明の第１実施形態に係る薄型電池の端子導出部は、完全な２自由度型マス-バネ系ではないため、上式により完全に説明することは出来ないが、上式を参考にして端子導出部における共振周波数のチューニングが可能である。なお、各層及び端子の材質の変更により、上式の質量、ヤング率を変化させて、端子導出部の共振周波数をチューニングしても良い。
【００２２】
電池外装部材を構成する各層の材質、膜厚、ヤング率と、正極端子及び負極端子の材質、厚さとを操作することにより、端子導出部のマス-バネ系における一次固有振動数、二次固有振動数を任意に設定することが可能となり、当該端子導出部の共振周波数を加振振動数から離遠させるように移行させ、共振を抑制することが可能となる。
【００２３】
図４は、第１実施形態に係る薄型電池の端子導出部における縦軸に加振振幅と応答振幅との比である振動伝達率、横軸に周波数の振動伝達率スペクトルを示す。同図に示すように、例えば、主たる加振振動数が約１００Ｈｚ以下に特に集中する車両等での薄型電池の使用する場合において、本発明の第１実施形態に係るチューニングにより、端子導出部の共振周波数を約１００Ｈｚ以上に移行させて加振振動数から離遠させることにより、加振に対する共振を防止して薄型電池を有効に活用することが可能となる。なお、加振振動数は約１００Ｈｚ以下に特に限定されず、それ以上の加振振動数に対しても、上記のチューニングを行うことが可能である。
【００２４】
さらに、図１に示すように、封止された電池外装１０６、１０７の一方の端部から、正極端子１０４が導出するが、正極端子１０４の厚さ分だけ上部電池外装１０６と下部電池外装１０７との接合部に隙間が生じるので、薄型電池１０内の封止性を維持するために、当該正極端子１０４と電池外装１０６、１０７とが接触する部分に、ポリエチレンやポリプロピレン等から構成されたシールフィルムを熱融着などの方法により介在させることもできる。
【００２５】
同様に、封止された電池外装１０６、１０７の他方の端部からは、負極端子１０５が導出するが、ここにも正極端子１０４側と同様に、当該負極端子１０５と電池外装１０６、１０７とが接触する部分にシールフィルムを介在させることもできる。なお、正極端子１０４および負極端子１０５の何れにおいても、シールフィルムは電池外装１０６，１０７を構成する樹脂と同系統の樹脂から構成することが熱融着性の点から望ましい。
【００２６】
これらの電池外装部材１０６、１０７によって、上述した発電要素１０９、正極側集電部１０４ａ、正極端子１０４の一部、負極側集電部１０５ａおよび負極端子１０５の一部を包み込み、当該電池外装部材１０６、１０７により形成される空間に、有機液体溶媒に過塩素酸リチウム、ホウフッ化リチウム等のリチウム塩を溶質とした液体電解質を注入したのち、上部電池外装部材１０６及び下部電池外装部材１０７の外周縁の熱融着領域１１０を熱プレスにより熱融着し、封止する。
【００２７】
このように封止された薄型電池１０は、総厚１〜１０［ｍｍ］を有することが好ましい。薄型電池の厚さを１０［ｍｍ］以下とすることにより、当該薄型電池内部に熱がこもりにくくなり、電池外装部材の界面に応力を伝達する可能性が低くなると共に、電池の熱劣化の影響も減少する。また、薄型電池の厚さを１［ｍｍ］以上とすることにより、十分な容量を確保することが出来、経済的な効率を高くすることが可能となる。
【００２８】
有機液体溶媒として、プロピレンカーボネート（ＰＣ）、エチレンカーボネート（ＥＣ）、ジメチルカーボネート（ＤＭＣ）などのエステル系溶媒を挙げることができるが、本発明の有機液体溶媒はこれにのみ限定されることなく、エステル系溶媒に、γ−ブチラクトン（γ−ＢＬ）、ジエトシキエタン（ＤＥＥ）等のエーテル系溶媒その他を混合、調合した有機液体溶媒も用いることができる。
【００２９】
以下に、上述の薄型電池を複数組み合わせることにより構成される組電池、及び当該組電池を複数組み合わせることにより構成される複合組電池について説明する。
【００３０】
図５は本発明の第１実施形態に係る複数の薄型電池の接続方法を示す図であり、図５（Ａ）は並列接続を示し、図５（Ｂ）は比較のための直列接続を示す。図６は本発明の第１実施形態に係る複数の薄型電池の他の接続方法を示す図であり、図６（Ａ）は並列接続を示し、図６（Ｂ）は比較のための直列接続を示す。図７は本発明の第１実施形態に係る複数の薄型電池により構成される組電池の斜視図、図８（Ａ）は図７の組電池の平面図、図８（Ｂ）は図７の組電池の正面図、図８（Ｃ）は図７の組電池の側面図、図９は図７の組電池より構成される複合組電池の斜視図、図１０（Ａ）は図９の複合組電池の平面図、図１０（Ｂ）は図９の複合組電池の正面図、図１０（Ｃ）は図９の複合組電池の側面図、図１１は本発明の第１実施形態に係る複合組電池を車両に搭載した模式図を示す。
【００３１】
上述の薄型電池１０を電気的に接続して複数の薄型電池１０を有する組電池２０を構成する場合、特に図５（Ａ）及び図６（Ａ）に示す配置による２つの接続構造が、印可される外力に対してさらに強い構造を付加する。
【００３２】
一つ目の接続構造は、図５（Ａ）に示すように、第１の薄型電池１０ａの正極端子１０４と、第２の薄型電池１０ｂの正極端子１０４とが同一方向に導出するような方向で、第１の薄型電池１０ａと第２の薄型電池１０ｂを実質的に同一平面上に並置させる。そして、第１の薄型電池１０ａの正極端子１０４と、第２の薄型電池１０ｂの正極端子１０４とを、第１のバスバー２１ａにより電気的に接続する。また、第１の薄型電池１０ａの負極端子１０５と第２の薄型電池１０ｂの負極端子１０５とを、第２のバスバー２１ｂにより電気的に接続する。
【００３３】
二つ目の接続構造は、図６（Ａ）に示すように、第１の薄型電池１０ａの正極端子１０４と、第２の薄型電池１０ｂの正極端子１０４とが同一方向に導出するような方向で、第１の薄型電池１０ａの鉛直上向きの面と第２の薄型電池１０ｂの鉛直下向きの面とを接触させて、第１の薄型電池１０ａと第２の薄型電池１０ｂとを積層する。そして、第１の薄型電池１０ａの正極端子１０４と第２の薄型電池１０ｂの正極端子１０４とを溶着して電気的に接続し、同様に、第１の薄型電池１０ａの負極端子１０５と第２の薄型電池１０ｂの負極端子１０５とを溶着して電気的に接続する。
【００３４】
図５（Ｂ）及び図６（Ｂ）に示すような直列に接続された場合、印加される外力によって、各薄型電池１０ａ、１０ｂの正極端子１０４には逆位相の捻れ（図５（Ｂ）及び図６（Ｂ）において捻れの方向を矢印により示す。）が生じるが、これに対し上記に説明した接続構造は、薄型電池１０ａ、１０ｂの正極端子１０４同士及び負極端子１０５同士が接続されているため、各薄型電池１０ａ、１０ｂに生じる応力が同位相となり、当該端子１０４、１０５に生じる捻れを極力抑えることが出来、端子と電池外装部材との間の界面に剥離が生じる可能性が低くなる。また、正極端子の金属と負極端子の金属とが異なる場合には、それに伴って、端子導出部に生ずる引張り応力も異なり界面剥離の原因になりうるが、上述の並列接続により薄型電池の端子導出部に生じる引張り応力を実質的に同等のものとすることが可能となる。
【００３５】
図７及び図８（Ａ）〜（Ｃ）は、例えば上述の２通りの接続構造を用いて並列接続された２４個の薄型電池１０から構成させる組電池２０を示す。組電池２０は、２４個の薄型電池１０と、組電池用端子２２、２３と、組電池用カバー２５とから構成されている。特に図示しないが、各薄型電池１０の各同極端子間は上述の接続構造でバスバー２１ａ、２１ｂにより並列接続されており、各正極端子１０４を接続する第１のバスバー２１ａは、組電池用カバー２５から導出する略円柱形状の組電池用正極端子２２に接続されている。同様に、各負極端子１０５を接続する第２のバスバー２１ｂは、組電池用カバー２５から導出する略円柱形状の組電池用負極端子２３に接続されている。これらの接続が完了し、２４個の薄型電池１０が組電池用カバー２５に挿入されると、当該組電池用カバー２５と当該組電池２０の他の構成要素との間に形成される空間に充填剤２４が充填され、封止される。さらに、後述する複合組電池として薄型電池が積層された際に、薄型電池同士の振動を極力低減するために、組電池用カバー２５の下面四隅に外部弾性体２６が取り付けられる。
【００３６】
図９及び図１０（Ａ）〜（Ｃ）は、図７に示す組電池２０を電気的に接続した６個の組電池２０から構成される複合組電池３０を示す。図９及び図１０（Ａ）〜（Ｃ）に示すように、複合組電池３０は、組電池２０の端子２２、２３がそれぞれ同一方向に向くように積層されている。すなわち、ｍ段目に位置する組電池２０の端子２２、２３と、ｍ＋１段目に位置する組電池２０の端子２２、２３とが同一方向に向くように、ｍ段目の組電池２０の上にｍ＋１段目の組電池２０が積層される（ｍ：自然数）。そして、同一方向を向いた全ての組電池２０の組電池用正極端子２２を、当該複合組電池３０と外部とを接続する外部接続用正極端子３１で電気的に接続する。同様に、同一方向を向いた全ての組電池２０の組電池用負極端子２３を、外部接続用負極端子３２で電気的に接続する。同図に示すように、外部接続用正極端子３１は、略矩形の平板形状であり、組電池用正極端子２２を挿入或いは圧入可能な直径を有する複数の端子接続用孔が加工されている。当該端子接続用孔は、積層された組電池２０の組電池用正極端子２２間のピッチに等しいピッチで加工されており、外部接続用負極端子３２にも同様に端子接続用孔が加工されている。
【００３７】
さらに、組電池用端子２２、２３が複合組電池３０の外部に露出しないように、接続された全ての組電池用端子２２、２３を覆うように、絶縁性の材料の絶縁カバー３３が具備されている。なお、図９において当該絶縁カバー３３は、説明の便宜上、透視図により描かれており、図１０には図示しない。そして、上述のように積層された６個の組電池２０は、その両側面部に平板状の連結部材３４で連結され、さらに固定ネジ３５により締結、固定される。
【００３８】
以上のように、薄型電池により所定の数を単位とした組電池を構成し、さらに当該組電池を単位として、所定の数の組電池を組み合わせて複合組電池を構成することにより、要求される容量、電圧等に適当な複合組電池を容易に得ることが可能となる。また、複雑な接続を伴うことなく複合組電池を構成するので、接続不良による、複合組電池の故障率を低減することが可能となる。さらに、複合組電池を構成する一つの薄型電池が故障或いは劣化し、当該薄型電池の交換を必要とする場合、当該薄型電池を有する組電池を容易に交換することも可能となる。
【００３９】
図１１は、車両１のフロア下に上述の複合組電池３０を車載した例を示す模式図である。車両１の移動に伴って、車内には多くの振動が発生する。同図に示すように、上述の複合組電池３０を車載することにより、当該振動により薄型電池の端子と電池外装部材との間に界面剥離が発生する可能性が著しく減少し、車両で電池を有効に活用することが可能となる。
【００４０】
なお、組電池を構成する薄型電池の数、複合組電池を構成する組電池の数、組電池を構成する薄型電池の接続方式、及び複合組電池を構成する組電池の接続方式は、上述の数及び接続方式に限定されるものではなく、要求される電気容量、電圧等から適宜その数及び接続方式（直列接続、並列接続、直列並列複合接続）を設定することが出来る。
【００４１】
第２実施形態
図１２は本発明の第２実施形態に係る薄型電池の端子導出部の拡大断面図である。なお、図１２は図１のIII部の拡大断面図に相当する。本発明の第２実施形態に係る薄型電池１０は、第１実施形態の電池外装部材１０６、１０７に接着層１０６ｄ、１０７ｄを新たに付与したものであり、当該薄型電池１０のその他の構成要素は、第１実施形態と同様である。
【００４２】
図１２に示すように、上部電池外装部材１０６の第１の樹脂層１０６ａと金属層１０６ｂとの間に接着層１０６ｄが新たに設けられている。同様に、下部電池外装部材１０７の第１の樹脂層１０７ａと金属層１０７ｂとの間に接着層１０７ｄが新たに設けられている。当該接着層１０６ｄが非常に弱い樹脂層を形成することにより、第１の樹脂層１０６ａと金属層１０６ｂとの動吸振器としての動的バネ特性を効率的に低減する。同様に、接着層１０７ｄが、第１の樹脂層１０７ａと金属層１０７ｂとの動吸振器としての動的バネ特性を効率的に低減する。
【００４３】
この第２実施形態に係る薄型電池を単位電池として用いて、第１実施形態と同様に当該薄型電池を複数接続した組電池、当該組電池を複数接続した複合組電池、及び当該複合組電池を車両に車載することが可能である。
【００４４】
第３実施形態
図１３は本発明の第３実施形態に係る端子導出部の拡大断面図であり、図１４は図１３の端子導出部のマス-バネ系モデルであり、図１５は本発明の第３実施形態に係る端子導出部での振動伝達率スペクトルを示すグラフである。なお、図１３は図１のIII部の拡大断面図に相当する。
【００４５】
本発明の第３実施形態に係る薄型電池１０は、第１実施形態の電池外装部材１０６の金属層１０６ｂと第１の樹脂層１０６ａとの間にさらに第３の樹脂層１０６ｅを新たに付与し、同様に下部電池外装部材１０７の金属層１０７ｂと第１の樹脂層１０７ａとの間にさらに第３の樹脂層１０７ｅを付与したものであり、当該薄型電池１０のその他の構成要素は、第１実施形態と同様である。なお、電池外装部材１０６、１０７の第１の樹脂層１０６ａ、１０７ａを、正極端子及び負極端子の近傍のみに配置されるシールフィルムとしても良い。
【００４６】
上部電池外装部材１０６の３つの樹脂層１０６ｃ、１０６ａ、１０６ｅのヤング率の関係は、第１の樹脂層１０６ａのヤング率が第２の樹脂層のヤング率に対して５〜５５％であり、第３の樹脂層１０６ｅのヤング率が第１の樹脂層１０６ｂのヤング率に対して９０〜１００％となるような関係を有している。同様に、下部電池外装部材１０７の３つの樹脂層１０７ｃ、１０７ａ、１０７ｅのヤング率の関係は、第１の樹脂層１０７ａのヤング率が第２の樹脂層１０７ｃのヤング率に対して５〜５５％であり、第３の樹脂層１０７ｅのヤング率が第１の樹脂層１０７ａのヤング率に対して９０〜１００％となるような関係を有している。
【００４７】
そして、上部電池外装部材１０６の第３の樹脂層１０６ｅは、第１の樹脂層１０６ａと直列接続され、図１４に示すように新たな第１のバネ部Ｋ’及び減衰要素Ｃ’を形成する。同様に、下部電池外装部材１０７の第３の樹脂層１０７ｅは、第１の樹脂層１０７ａと直列接続され、同図に示すように新たな第１のバネ部Ｋ’及び減衰要素Ｃ’を形成する。端子導出部１１１のマス-バネ系モデルにおいて、直列接続された新たな第１のバネ部Ｋ’及び減衰要素Ｃ’を形成することにより、第１の樹脂層１０６ａ、１０７ａと金属層１０６ｂ、１０７ｂとによる動吸振器としての動的バネ特性を効率的に低減する。
【００４８】
特に第３の樹脂層１０６ｅ、１０７ｅのヤング率が、第１の樹脂層１０６ａ、１０７ａのヤング率に対して９０〜１００％となるように設定することにより、端子導出部１１１のマスバネ系における動的バネ特性がヤング率の低い樹脂層に一方的に依存するのを防止し、端子導出部における共振周波数の移行が容易となる。
【００４９】
図１５は、第３実施形態に係る薄型電池の端子導出部における縦軸に加振振幅と応答振幅との比である振動伝達率、横軸に周波数の振動伝達率スペクトルを示す。同図に示すように、例えば、主たる加振振動数が約１００Ｈｚ以下に特に集中する車両等での薄型電池の使用する場合において、本発明の第３実施形態に係るチューニングにより、端子導出部の共振周波数を約１００Ｈｚ以上に移行させて加振振動数から離遠させることにより、加振に対する共振を防止して薄型電池を有効に活用することが可能となる。なお、加振振動数は約１００Ｈｚ以下に特に限定されず、それ以上の加振振動数に対しても、上記のチューニングを行うことが可能である。
【００５０】
この第３実施形態に係る薄型電池を単位電池として用いて、第１実施形態と同様に当該薄型電池を複数接続した組電池、当該組電池を複数接続した複合組電池、及び当該複合組電池を車両に車載することが可能である。
【００５１】
なお、以上説明した実施形態は、本発明の理解を容易にするために記載されたものであって、本発明を限定するために記載されたものではない。したがって、上記の実施形態に開示された各要素は、本発明の技術的範囲に属する全ての設計変更や均等物をも含む趣旨である。
【００５２】
【実施例】
以下、本発明をさらに具体化した実施例及び比較例により本発明の効果を確認した。以下の実施例は、上述した実施形態で用いた薄型電池の効果を確認するためのものである。
【００５３】
実施例１
実施例１の薄型電池は、正極端子に厚さ１００μｍのアルミニウム（Ａｌ）箔、負極端子に厚さ１００μｍの銅（Ｃｕ）箔、正極活性物質にマンガン酸リチウム（ＬｉＭｎＯ_２）、負極活性物質に非結晶性炭素材、電解液にプロピレンカーボネート（ＰＣ）及びエチルメチルカーボネート（ＥＭＣ）の混合液を用いた。また、第１の樹脂層に膜厚８０μｍのポリエチレン（ＰＥ）樹脂フィルム、金属層に膜厚４０μｍのアルミニウム（Ａｌ）箔、第２の樹脂層に膜厚２０μｍのナイロン樹脂フィルムを図２のように積層した高分子金属複合フィルムを上部電池外装部材及び下部電池外装部材として用いて縦１４０ｍｍ×横８０ｍｍ×厚さ４ｍｍの薄型電池を作製した。なお、第１の樹脂層のポリエチレン樹脂フィルムのヤング率は、０．０８×１０^−１０Ｎ／ｍ^２であり、第２の樹脂層のナイロン樹脂フィルムのヤング率は、０．２５×１０^−１０Ｎ／ｍ^２である。従って、第２の樹脂層のヤング率に対する第１の樹脂層のヤング率の比率は３２％であり、正極端子及び負極端子の厚さは、金属層の膜厚に対して２．５倍となった。実施例１において作製した薄型電池の条件を表１に示す。
【００５４】
【表１】

【００５５】
この薄型電池について、加速度比の測定及び平均減衰率の測定を行った。加速度比の測定は、当該薄型電池の端子の略中央部に加速度ピックアップを設定し、１０Ｈｚ、５０Ｈｚ、１００Ｈｚでそれぞれ強制加振したときに得られる応答振動の加速度値を測定した。この際、比較例に対する加速度値を基準にして比率を算出することにより加速度比を算出した。なお、実施例１に対する基準は後述する比較例１である。この加速度比は、その値が１．０のときは、実施例と比較例の加速度の絶対値が同一であることを示し、加速度比の値が０．０〜１．０のときは、強制加振に対して応答振動が低減したことを示し、加速度比の値が１．０以上のときは強制振動に共振して応答振動が増幅されたことを意味する。
【００５６】
また、平均低減率の測定は、上述の加速度比を１０〜３００Ｈｚで測定し、その低減率を平均化したものであり、数値が大きいほど、全体的に振動が低減されたことを示す。
【００５７】
この結果、表２に示すように実施例１における加速度比測定では、１０Ｈｚ：０．２７、５０Ｈｚ：０．３２、１００Ｈｚ：０．３０となり、各加振振動数において振動の低減が確認された。また、実施例１における平均低減率の測定は約５０％となり、全体として振動の低減が確認された。なお、本実施例の振動伝達スペクトルは図４に示すように、共振周波数が移行して約１００Ｈｚ以上になっていることが確認され、本実施例の第１固有振動数は比較例１の第１固有振動数に対して高周波数側への移行量は約５０Ｈｚ分移行した。
【００５８】
【表２】

【００５９】
実施例２
実施例２の薄型電池には、実施例１と同様の正極活性物質、負極活性物質、電解液を用い、正極端子に厚さ２００μｍのアルミニウム（Ａｌ）箔、負極端子に厚さ２００μｍのニッケル（Ｎｉ）箔を用いた。また、第１の樹脂層に膜厚８０μｍのポリエチレン（ＰＥ）樹脂フィルム、金属層に膜厚４０μｍのアルミニウム（Ａｌ）箔、第２の樹脂層に膜厚２０μｍのナイロン樹脂フィルム、そして第１の樹脂層と金属層との界面にウレタン系接着剤の接着層を設けた図１２に示すような高分子金属複合フィルムを上部電池外装部材及び下部電池外装部材として用いて縦１４０ｍｍ×横８０ｍｍ×厚さ４ｍｍの薄型電池を作製した。なお、第１の樹脂層のポリエチレン樹脂フィルムのヤング率は、０．０８×１０^−１０Ｎ／ｍ^２であり、第２の樹脂層のナイロン樹脂フィルムのヤング率は、０．２５×１０^−１０Ｎ／ｍ^２である。従って、第２の樹脂層のヤング率に対する第１の樹脂層のヤング率の比率は３２％であり、正極端子及び負極端子の厚さは、金属層の膜厚に対して５．０倍となった。実施例２において作製した薄型電池の条件を表１に示す。
【００６０】
この薄型電池について、第１実施例と同様の条件で、加速度比測定及び平均低減率測定を行った。その結果、表２に示すように、加速度比測定においては、基準に対して、１０Ｈｚ：０．２５、５０Ｈｚ：０．３、１００Ｈｚ：０．２９となり、各加振振動数において振動の低減が確認された。また、実施例２における平均低減率測定は約４０％となり、全体として振動の低減が確認された。なお、本実施例の第１固有振動数は比較例１の第１固有振動数に対して高周波数側に約６０Ｈｚ分移行し、約１００Ｈｚ以上に位置した。
【００６１】
実施例３
実施例３の薄型電池には、実施例１と同様の正極活性物質、負極活性物質、電解液を用い、正極端子に厚さ１００μｍのアルミニウム（Ａｌ）箔、負極端子に厚さ１００μｍの鉄（Ｆｅ）箔を用いた。また、第１の樹脂層に膜厚４０μｍの変性ポリプロピレン（ＰＰ）、金属層に膜厚５０μｍのアルミニウム（Ａｌ）箔、第２の樹脂層に膜厚２５μｍのナイロン樹脂フィルム、そして第１の樹脂層と金属層との間に膜厚４０μｍのポリプロピレン（ＰＰ）樹脂フィルムの第３の樹脂層を図１３に示すように積層した高分子金属複合フィルムを上部電池外装部材及び下部電池外装部材として用いて、縦１４０ｍｍ×横８０ｍｍ×厚さ４ｍｍの薄型電池を作製した。実施例３で作製した薄型電池の条件を表１に示す。なお、第１の樹脂層の変性ポリプロピレンのヤング率は、０．１２×１０^−１０Ｎ／ｍ^２であり、第２の樹脂層のナイロン樹脂フィルムのヤング率は、０．２５×１０^−１０Ｎ／ｍ^２であり、第３の樹脂層のポリプロピレンのヤング率は、０．１３×１０^−１０Ｎ／ｍ^２である。従って、第２の樹脂層のヤング率に対する第１の樹脂層のヤング率の比率は４８％であり、第１の樹脂層のヤング率に対する第３の樹脂層のヤング率の比率は約９２％であり、正極端子及び負極端子の厚さは、金属層の膜厚に対して２．０倍となった。実施例３において作製した薄型電池の条件を表１に示す。
【００６２】
この薄型電池について、第１実施例と同様の条件で、加速度比測定及び平均低減率測定を行った。その結果、表２に示すように、加速度比測定においては、基準に対して、１０Ｈｚ：０．３０、５０Ｈｚ：０．３５、１００Ｈｚ：０．３４となり、各加振振動数において振動の低減が確認された。また、実施例３における平均低減率測定は約４５％となり、全体として振動の低減が確認された。なお、本実施例の振動伝達スペクトルは図１５に示すように、共振周波数が移行して１００Ｈｚ以上になっていることが確認され、本実施例の第１固有振動数は比較例２の第１共振周波数に対して高周波側に約４０Ｈｚ分移行した。
【００６３】
実施例４
実施例４の薄型電池には、正極端子に厚さ２５０μｍのアルミニウム（Ａｌ）箔、負極端子に厚さ２５０μｍのニッケル（Ｎｉ）箔を用い、その他の構成要素については実施例３と同様のものを用いて、縦１４０ｍｍ×横８０ｍｍ×厚さ４ｍｍの薄型電池を作製した。実施例４で作製した薄型電池の条件を表１に示す。
【００６４】
この薄型電池について、第１実施例と同様の条件で、加速度比測定及び平均低減率測定を行った。その結果、表２に示すように、加速度比測定においては、基準に対して１０Ｈｚ：０．２７、５０Ｈｚ：０．３２、１００Ｈｚ：０．３３となり、各加振振動数において振動の低減が確認された。また、実施例４における平均低減率測定は約５０％となり、全体として振動の低減が確認された。なお、本実施例の第１共振周波数は比較例２の第１共振周波数に対して高周波数側に約８０Ｈｚ分移行し、１００Ｈｚ以上に位置した。
【００６５】
比較例１
比較例１の薄型電池は、電池外装部材の第２の樹脂層に膜厚２０μｍ、ヤング率０．１２×１０^−１０Ｎ／ｍ^２のナイロン樹脂フィルムを用い、薄型電池の他の構成要素は実施例１と同様である。なお、第２の樹脂層のヤング率に対する第１の樹脂層のヤング率の比率は約６７％である。
【００６６】
比較例２
比較例２の薄型電池は、電池外装部材の第２の樹脂層に膜厚２５μｍ、ヤング率０．１２×１０^−１０Ｎ／ｍ^２のナイロン樹脂フィルムを用い、薄型電池の他の構成要素は実施例３と同様である。なお、第２の樹脂層のヤング率に対する第１の樹脂層のヤング率の比率は約９２％である。
【００６７】
考察
実施例１〜４と比較例１、２とを比較して、共振周波数を移行させて加振周波数から離し、全体周波数において振動が低減されていることが確認され、実施例１〜４の薄型電池は印加される振動に対して強い構造を有することが明らかとなった。
【図面の簡単な説明】
【図１】図１（Ａ）は本発明の第１実施形態に係る薄型電池の全体を示す平面図、図１（Ｂ）は（Ａ）のII−II線に沿う断面図である。
【図２】図１（Ａ）のIII部の拡大断面図である。
【図３】図２の端子導出部のマスバネ系モデルである。
【図４】本発明の第１実施形態に係る端子導出部での振動伝達率スペクトルを示すグラフである。
【図５】本発明の第１実施形態に係る複数の薄型電池の接続構造を示す図であり、図５（Ａ）は並列接続を示し、図５（Ｂ）は比較のための直列接続を示す。
【図６】本発明の第１実施形態に係る複数の薄型電池の他の接続構造を示す図であり、図６（Ａ）は並列接続を示し、図６（Ｂ）は比較のための直列接続を示す。
【図７】本発明の第１実施形態に係る複数の薄型電池により構成される組電池の斜視図である。
【図８】図８（Ａ）は図７の組電池の平面図、図８（Ｂ）は図７の組電池の正面図、図８（Ｃ）は図７の組電池の側面図である。
【図９】図７の組電池により構成される複合組電池の斜視図である。
【図１０】図１０（Ａ）は図９の複合組電池の平面図、図１０（Ｂ）は図９の複合組電池の正面図、図１０（Ｃ）は図９の複合組電池の側面図である。
【図１１】本発明の第１実施形態に係る複合組電池を車両に搭載した模式図である。
【図１２】本発明の第２実施形態に係る端子導出部の拡大断面図である。
【図１３】本発明の第３実施形態に係る端子導出部の拡大断面図である。
【図１４】図１３のマスバネ系モデルである。
【図１５】本発明の第３実施形態に係る端子導出部での振動伝達率スペクトルを示すグラフである。
【符号の説明】
１…車両
１０…薄型電池
１０ａ…第１の薄型電池
１０ｂ…第２の薄型電池
１０１…正極板
１０２…セパレータ
１０３…負極板
１０４…正極端子
１０５…負極端子
１０６…上部電池外装部材
１０６ｃ…第２の樹脂層
１０６ｂ…金属層
１０６ａ…第１の樹脂層
１０６ｄ…接着層
１０６ｅ…第３の樹脂層
１０７…下部電池外装部材
１０７ｃ…第２の樹脂層
１０７ｂ…金属層
１０７ａ…第１の樹脂層
１０７ｄ…接着層
１０７ｅ…第３の樹脂層
１０９…発電要素
１１０…熱融着領域
１１１…端子導出部
２０…組電池
２１ａ…第１のバスバー
２１ｂ…第２のバスバー
２２…組電池用正極端子
２３…組電池用負極端子
２４…充填剤
２５…組電池用カバー
２６…外部弾性体
３０…複合組電池
３１…外部接続用正極端子
３２…外部接続用負極端子
３３…絶縁カバー
３４…連結部材
３５…固定ネジ[0001]
【Technical field】
The present invention relates to a thin battery having a terminal derived from an edge of an outer peripheral portion of a sealing means, and particularly to a thin battery having a structure strong against applied vibration.
[0002]
[Background]
With the diversification of the usage mode and usage conditions of the thin battery having terminals derived from the edge of the outer peripheral portion of the sealing means, the vibration applied from the outside to the thin battery increases. Due to this vibration, the electrolyte injected into the thin battery leaks due to peeling of a portion where the positive electrode terminal or the negative electrode terminal is derived from the battery exterior member (hereinafter also referred to simply as a terminal lead-out portion), and the performance of the thin battery It may cause a decrease.
[0003]
DISCLOSURE OF THE INVENTION
An object of this invention is to provide the thin battery which has a structure strong with respect to the applied external force.
[0004]
In order to achieve the above object, according to the present invention, at least one metal layer sandwiched between two synthetic resin layers is provided.The outer peripheral edge of two exterior members is fused.A sealing means,A power generation element composed of a positive electrode plate, a separator, a negative electrode plate, and an electrolyte is sealed in the sealing means and connected to the positive electrode platePositive terminal andConnected to the negative electrode plateA thin battery in which a negative electrode terminal is led out from an edge of an outer peripheral portion of the sealing means,Exterior memberThe first synthetic resin layer located in the innermost layer of theExterior memberA thin battery having a Young's modulus smaller than that of the second synthetic resin layer located in the outermost layer is provided (see claim 1).
[0005]
In the present invention, the resonance of the terminal lead-out portion is achieved by operating the Young's modulus of the innermost first synthetic resin layer of the battery exterior member to be smaller than the Young's modulus of the second outermost synthetic resin layer. The frequency is shifted away from the vibration frequency to prevent resonance. Thereby, the occurrence of peeling of the terminal lead-out portion due to vibration applied from the outside can be remarkably reduced, and a thin battery having a structure strong against the applied vibration can be obtained.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First embodiment
FIG. 1A is a plan view showing the entire thin battery according to the first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line II-II in FIG. FIG. 2 is an enlarged cross-sectional view of a portion III in FIG. FIG. 3 is the mass-spring system model of FIG. FIG. 4 is a graph showing a vibration transmissibility spectrum at the terminal derivation unit according to the first embodiment of the present invention. FIG. 1 shows one thin battery (unit battery), and an assembled battery having a desired voltage and capacity is formed by stacking a plurality of thin batteries 10.
[0007]
First, the overall configuration of the thin battery 10 according to the first embodiment of the present invention will be described with reference to FIG. 1. The thin battery 10 of this example is a lithium-based thin secondary battery, and includes two positive electrode plates 101. And five separators 102, two negative plates 103, a positive electrode terminal 104, a negative electrode terminal 105, an upper battery outer member 106, a lower battery outer member 107, and an electrolyte (not shown). Yes. Among these, the positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolyte are particularly referred to as a power generation element 109.
[0008]
The number of positive plates 101, separators 102, and negative plates 103 is not limited in any way, and the power generation element 109 can be configured with one positive plate 101, three separators 102, and one negative plate 104. . The number of positive electrode plates, negative electrode plates, and separators can be selected and configured as necessary.
[0009]
The positive electrode plate 101 that constitutes the power generation element 109 includes, for example, 100 weight ratio of a positive electrode active material such as a metal oxide, a conductive material such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene. : A mixture of 3:10 is applied to both surfaces of a metal foil such as an aluminum foil as a positive electrode side current collector, dried, rolled, and then cut into a predetermined size. In addition, the mixing ratio of said aqueous dispersion of polytetrafluoroethylene is the solid content.
[0010]
As the positive electrode active material, for example, lithium nickelate (LiNiO)₂), Lithium manganate (LiMnO)₂), Lithium cobaltate (LiCoO)₂) And the like, and chalcogen (S, Se, Te) compounds. These materials are relatively easy to diffuse the heat generated inside the thin battery, can reduce the expansion caused by the expansion of the terminal due to the heat transfer to the terminal, and can suppress the tensile stress transmitted from the terminal to the battery exterior member described later as much as possible. It becomes.
[0011]
The negative electrode plate 103 constituting the power generation element 109 is made of a negative electrode active material that occludes and releases lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of an organic fired body is mixed at a solid content ratio of, for example, 100: 5, dried and then pulverized to support carbonized styrene butadiene rubber on the surface of carbon particles The resulting material is mixed with a binder such as an acrylic resin emulsion at a weight ratio of, for example, 100: 5, and this mixture is used as a metal foil such as nickel foil or copper foil as a negative electrode side current collector. These are coated on both sides, dried, rolled, and then cut into a predetermined size.
[0012]
In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. However, when used as a power source for an electric vehicle or the like, it is advantageous because there is no sudden drop in output.
[0013]
In addition, the separator 102 of the power generation element 109 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 described above, and may have a function of holding an electrolyte. The separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation, thereby blocking the current. It also has.
[0014]
The separator 102 of the present invention is not limited to a single-layer film such as polyolefin, but a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic nonwoven fabric can be used. . By forming the separator 102 in multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (rigidity improvement) function can be provided. Further, instead of the separator 102, a gel electrolyte or an intrinsic polymer electrolyte can be used.
[0015]
The above power generation element 109 is laminated in such an order that the positive electrode plate 101 and the negative electrode plate 103 are alternately arranged from above and the separator 102 is positioned between the positive electrode plate 101 and the negative electrode plate 103. The separators 102 are stacked one by one on the top and bottom. Each of the two positive plates 101 is connected to the positive terminal 104 made of metal foil via the positive current collector 104a, while the two negative plates 103 are connected to the negative current collector 105a. Is connected to the negative electrode terminal 105 which is also made of metal foil. The positive electrode terminal 104 and the negative electrode terminal 105 are not particularly limited as long as they are electrochemically stable metal materials. Examples of the positive electrode terminal 104 include aluminum, an aluminum alloy, copper, and nickel. Can include nickel, copper, stainless steel or iron. These metals are particularly suitable as components of thin batteries in terms of the resistance value, linear expansion coefficient, and resistivity of the metal, and even when the operating temperature is changed, the tensile stress transmitted from the terminal to the battery exterior member described later is transmitted. It is possible to suppress as much as possible. Further, both the positive electrode side current collector 104a and the negative electrode side current collector 105a in this example extend the aluminum foil, nickel foil, copper foil, and iron foil constituting the current collector of the positive electrode plate 104 and the negative electrode plate 105. However, the

current collectors

104a and 105a can be formed of separate materials and parts.
[0016]
The power generation element 109 is sealed by the upper battery exterior member 106 and the lower battery exterior member 107 (sealing means). As shown in FIG. 2, the upper battery exterior member 106 according to the first embodiment of the present invention includes a first resin layer 106a, a metal layer 106b, and a second resin layer 106c from the inside to the outside of the thin battery 10. Three layers 106a to 106c are stacked in this order. The three layers 106a to 106c are laminated over the entire surface of the upper battery exterior member 106, and the first resin layer 106a is resistant to an electrolytic solution such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, and ionomer. And a resin film excellent in heat-fusibility. The second resin layer 106c is a resin film excellent in electrical insulation, such as a polyamide resin or a polyester resin. As described above, the first resin layer of the battery exterior member is made of a resin such as polypropylene, modified polypropylene, polyethylene, modified polyethylene, or ionomer, so that the positive electrode terminal or the negative electrode terminal made of metal and the first of the battery exterior member are formed. It is possible to ensure good fusion with the resin layer. The metal layer 106b is, for example, a metal foil such as aluminum. Therefore, for example, the upper battery exterior member 106 is formed by laminating one surface of a metal foil such as aluminum (inner surface of a thin battery) with a resin such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, ionomer, and the other surface ( The outer surface of the thin battery is formed of a flexible material such as a resin-metal thin film laminate material obtained by laminating a polyamide resin, a polyester resin, or the like. Thus, when the battery exterior member includes the metal layer in addition to the resin layer, the strength of the battery exterior member can be improved. Note that the second resin layer 106c has a thickness relatively smaller than the thickness of the metal layer 106b and the thickness of the first resin layer 106a, and the first resin layer 106a and the metal layer 106b It is possible to effectively act the dynamic vibration absorber characteristics described later.
[0017]
The lower battery exterior member 107 has the same structure as the upper battery exterior member 106. As shown in FIG. 2, the first resin layer 107a and the metal layer 107b are formed from the inside to the outside of the thin battery 10 as shown in FIG. The three layers 107a to 107c are stacked in the order of the second resin layer 107c. Similar to the first resin layer 106a of the upper battery exterior member 106, the first resin layer 107a of the lower battery exterior member 107 is resistant to electrolyte solution and heat such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, and ionomer. It is a resin film excellent in fusing property. The metal layer 107b of the lower battery exterior member 107 is, for example, a metal foil such as aluminum, like the metal layer 106b of the upper battery exterior member 106. Similar to the second resin layer 106c of the upper battery exterior member 106, the second resin layer 107c of the lower battery exterior member 107 is a resin film excellent in electrical insulation, such as a polyamide resin or a polyester resin. . The second resin layer 107c has a thickness relatively smaller than the thickness of the metal layer 107b and the thickness of the first resin layer 107a, and will be described later by the first resin layer 107a and the metal layer 107b. It is possible to effectively act the dynamic vibration absorber characteristics.
[0018]
Further, the terminal derivation unit 111 composed of the positive electrode terminal 104 or the negative electrode terminal 105 and the

battery exterior members

106 and 107 is shifted so as to separate the resonance frequency of the terminal derivation unit 111 from the excitation frequency. In order to prevent resonance in the terminal lead-out part 111, a two-degree-of-freedom mass-spring system as shown in FIG. 3 is configured. In the mass-spring system model of FIG. 3, the positive electrode terminal 104 or the negative electrode terminal 105 of the thin battery 10 has a mass m.₁The metal layers 106b and 107b of the

battery exterior members

106 and 107 are mass m.₂This corresponds to the second mass portions Ma and Mb. Further, the first resin layer 106a of the upper battery exterior member 106 and the first resin layer 107a of the lower battery exterior member 107 have a Young's modulus k.₁The second resin layers 106c and 107c of the

battery exterior members

106 and 107 correspond to the first spring portion K and the damping element C, respectively.₂Corresponding to the second spring portions Ka and Kb of the first spring portion K.₁Is the Young's modulus k of the second spring part Ka, Kb₂5 to 55% of the relationship. Thus, the second spring portions Ka and Kb are replaced with the Young's modulus k of the first spring portion K.₂Smaller Young's modulus k₁By doing so, the

first resin layers

106a and 107a that are the first spring portions K and the metal layers 106b and 107b that are the second mass portions Ma and Mb effectively act as a dynamic vibration absorber. It is possible to shift the resonance frequency of the mass-spring system of the terminal derivation unit 111 so as to be separated from the vibration frequency. The Young's modulus k of the first spring part K₁Is the Young's modulus k of the second spring part Ka, Kb₂If it is less than 5%, the difference in the dynamic spring constant between the first spring part K and the second spring parts Ka, Kb becomes excessive, and the structure of the terminal lead-out part 111 may be weakened. Further, the Young's modulus k of the first spring portion K₁Is the Young's modulus k of the second spring part Ka, Kb₂Is greater than 55%, the difference in the dynamic spring constant depending on the Young's modulus is small, and the action of the dynamic vibration absorber by the second mass portions Ma and Mb and the first spring portion K is weakened. It becomes difficult to shift the resonance frequency of the portion 111.
[0019]
The positive electrode terminal 104 and the negative electrode terminal 105 described above have a thickness 2 to 5 times the film thickness of the metal layers 106b and 107b of the

battery exterior members

106 and 107. Here, when the thickness of the positive electrode terminal 104 and the negative electrode terminal 105 is less than twice the film thickness of the metal layers 106b and 107b, the influence of the metal layers 106b and 107b on the resonance frequency of the terminal lead-out part 111 increases. It may be difficult to shift the resonance frequency of the terminal lead-out unit 111. Further, if the thickness of the positive electrode terminal 104 and the negative electrode terminal 105 is larger than five times the film thickness of the metal layers 106b and 107b, the influence of the metal layers 106b and 107b on the resonance frequency of the terminal lead-out portion 111 is reduced. It becomes difficult to shift to the vibration frequency.
[0020]
Resonance frequency (natural frequency) ω in the mass-spring system with two degrees of freedom described above₁, Ω₂Can be substantially calculated from Equation 1.
[0021]
[Formula 1]

Since the terminal lead-out part of the thin battery according to the first embodiment of the present invention is not a complete two-degree-of-freedom type mass-spring system, it cannot be fully described by the above formula, but referring to the above formula Tuning of the resonance frequency in the terminal lead-out part is possible. The resonance frequency of the terminal lead-out part may be tuned by changing the mass and Young's modulus of the above equation by changing the material of each layer and terminal.
[0022]
By adjusting the material, film thickness, Young's modulus of each layer constituting the battery exterior member, and the material and thickness of the positive electrode terminal and negative electrode terminal, the primary natural frequency and secondary natural frequency in the mass-spring system of the terminal lead-out part The frequency can be arbitrarily set, and the resonance frequency of the terminal derivation unit can be shifted away from the excitation frequency to suppress resonance.
[0023]
FIG. 4 shows the vibration transmissibility that is the ratio of the excitation amplitude to the response amplitude on the vertical axis and the vibration transmissibility spectrum of the frequency on the horizontal axis in the terminal lead-out portion of the thin battery according to the first embodiment. As shown in the figure, for example, in the case of using a thin battery in a vehicle or the like where the main vibration frequency is particularly concentrated to about 100 Hz or less, the tuning of the terminal lead-out unit is performed by tuning according to the first embodiment of the present invention. By shifting the resonance frequency to about 100 Hz or more and moving away from the vibration frequency, resonance with respect to vibration can be prevented and the thin battery can be used effectively. The vibration frequency is not particularly limited to about 100 Hz or less, and the above tuning can be performed for vibration frequencies higher than that.
[0024]
Further, as shown in FIG. 1, the positive terminal 104 is led out from one end of the sealed

battery casings

106 and 107, but the upper battery casing 106 and the lower battery casing 107 are equivalent to the thickness of the positive terminal 104. In order to maintain the sealing performance in the thin battery 10, a seal made of polyethylene, polypropylene, or the like is provided at a portion where the positive electrode terminal 104 and the

battery exterior

106, 107 are in contact with each other. The film can be interposed by a method such as heat fusion.
[0025]
Similarly, the negative electrode terminal 105 is led out from the other end of the sealed

battery casings

106 and 107, and here, similarly to the positive terminal 104 side, the negative electrode terminal 105 and the

battery casings

106 and 107 It is also possible to interpose a seal film at the portion where the contacts. In any of the positive electrode terminal 104 and the negative electrode terminal 105, it is desirable from the viewpoint of heat-sealability that the seal film is made of a resin of the same system as the resin constituting the

battery casings

106 and 107.
[0026]
The

battery exterior members

106 and 107 enclose the power generation element 109, the positive current collector 104a, a part of the positive terminal 104, the negative current collector 105a, and a part of the negative terminal 105, and the battery exterior member. After injecting a liquid electrolyte having a lithium salt such as lithium perchlorate or lithium borofluoride into an organic liquid solvent into the space formed by 106, 107, the outer surfaces of the upper battery outer member 106 and the lower battery outer member 107 are removed. The peripheral heat-sealed region 110 is heat-sealed by hot pressing and sealed.
[0027]
The thin battery 10 thus sealed preferably has a total thickness of 1 to 10 [mm]. By setting the thickness of the thin battery to 10 [mm] or less, it becomes difficult for heat to be accumulated inside the thin battery, the possibility of transmitting stress to the interface of the battery exterior member is reduced, and the influence of the thermal deterioration of the battery Also decreases. Further, by setting the thickness of the thin battery to 1 [mm] or more, a sufficient capacity can be ensured, and economic efficiency can be increased.
[0028]
Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC), but the organic liquid solvent of the present invention is not limited thereto, An organic liquid solvent prepared by mixing and preparing an ether solvent such as γ-butylactone (γ-BL) and dietoshikiethane (DEE) in an ester solvent can also be used.
[0029]
Hereinafter, an assembled battery configured by combining a plurality of the above-described thin batteries and a composite assembled battery configured by combining a plurality of the assembled batteries will be described.
[0030]
5A and 5B are diagrams showing a method for connecting a plurality of thin batteries according to the first embodiment of the present invention. FIG. 5A shows parallel connection, and FIG. 5B shows serial connection for comparison. . 6A and 6B are diagrams showing another connection method for a plurality of thin batteries according to the first embodiment of the present invention, where FIG. 6A shows parallel connection and FIG. 6B shows series connection for comparison. Indicates. 7 is a perspective view of an assembled battery including a plurality of thin batteries according to the first embodiment of the present invention, FIG. 8A is a plan view of the assembled battery of FIG. 7, and FIG. 8B is FIG. FIG. 8C is a side view of the assembled battery of FIG. 7, FIG. 9 is a perspective view of a composite assembled battery composed of the assembled battery of FIG. 7, and FIG. 10A is the composite of FIG. FIG. 10 (B) is a front view of the composite battery pack of FIG. 9, FIG. 10 (C) is a side view of the composite battery pack of FIG. 9, and FIG. 11 is related to the first embodiment of the present invention. The schematic diagram which mounted the composite assembled battery in the vehicle is shown.
[0031]
When the assembled battery 20 having the plurality of thin batteries 10 is configured by electrically connecting the thin batteries 10 described above, two connection structures having the arrangements shown in FIGS. 5A and 6A are particularly applicable. A structure that is stronger against external force is added.
[0032]
As shown in FIG. 5A, the first connection structure is a direction in which the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are led out in the same direction. Thus, the first thin battery 10a and the second thin battery 10b are juxtaposed on substantially the same plane. Then, the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are electrically connected by the first bus bar 21a. Further, the negative terminal 105 of the first thin battery 10a and the negative terminal 105 of the second thin battery 10b are electrically connected by the second bus bar 21b.
[0033]
In the second connection structure, as shown in FIG. 6A, the positive terminal 104 of the first thin battery 10a and the positive terminal 104 of the second thin battery 10b are led out in the same direction. Thus, the first thin battery 10a and the second thin battery 10b are stacked by bringing the vertically upward surface of the first thin battery 10a into contact with the vertically downward surface of the second thin battery 10b. Then, the positive electrode terminal 104 of the first thin battery 10a and the positive electrode terminal 104 of the second thin battery 10b are welded and electrically connected, and similarly, the negative electrode terminal 105 of the first thin battery 10a and the second terminal The thin-film battery 10b is electrically connected to the negative electrode terminal 105 by welding.
[0034]
When connected in series as shown in FIG. 5 (B) and FIG. 6 (B), the positive terminal 104 of each

thin battery

10a, 10b is twisted in the opposite phase by the applied external force (FIG. 5 (B)). 6 (B), the direction of twisting is indicated by an arrow.) However, in the connection structure described above, the positive terminals 104 and the negative terminals 105 of the

thin batteries

10a and 10b are connected to each other. Therefore, the stresses generated in the

thin batteries

10a and 10b are in the same phase, the twist generated in the

terminals

104 and 105 can be suppressed as much as possible, and the possibility that the interface between the terminals and the battery exterior member is peeled off is low. Become. In addition, if the metal of the positive electrode terminal and the metal of the negative electrode terminal are different, the tensile stress generated in the terminal lead-out portion may be different and cause interfacial delamination. It is possible to substantially equalize the tensile stress generated in the part.
[0035]
FIGS. 7 and 8A to 8C show an assembled battery 20 composed of 24 thin batteries 10 connected in parallel using, for example, the above-described two connection structures. The assembled battery 20 includes 24 thin batteries 10, assembled

battery terminals

22 and 23, and an assembled battery cover 25. Although not shown in particular, the same-polarity terminals of each thin battery 10 are connected in parallel by the bus bars 21a and 21b in the above-described connection structure, and the first bus bar 21a connecting each positive terminal 104 is an assembled battery cover. 25 is connected to a substantially cylindrical assembled battery positive electrode terminal 22 led out from 25. Similarly, the second bus bar 21 b connecting each negative electrode terminal 105 is connected to a substantially cylindrical assembled battery negative terminal 23 that is led out from the assembled battery cover 25. When these connections are completed and 24 thin batteries 10 are inserted into the assembled battery cover 25, a space formed between the assembled battery cover 25 and the other components of the assembled battery 20 is formed. Filler 24 is filled and sealed. Furthermore, when thin batteries are stacked as a composite battery pack, which will be described later, in order to reduce vibration between the thin batteries as much as possible, external elastic bodies 26 are attached to the bottom four corners of the battery pack cover 25.
[0036]
FIGS. 9 and 10A to 10C show a composite battery pack 30 including six battery packs 20 electrically connected to the battery pack 20 shown in FIG. As shown in FIG. 9 and FIGS. 10A to 10C, the composite battery pack 30 is stacked such that the

terminals

22 and 23 of the battery pack 20 face in the same direction. That is, the

terminals

22 and 23 of the assembled battery 20 located at the m-th stage and the

terminals

22 and 23 of the assembled battery 20 located at the (m + 1) -th stage are oriented in the same direction. M + 1-stage assembled batteries 20 are stacked (m: natural number). Then, the assembled battery positive terminals 22 of all assembled batteries 20 facing in the same direction are electrically connected by the external connection positive terminal 31 that connects the composite assembled battery 30 and the outside. Similarly, the assembled battery negative terminals 23 of all assembled batteries 20 facing in the same direction are electrically connected by the external connection negative terminal 32. As shown in the figure, the external connection positive electrode terminal 31 has a substantially rectangular flat plate shape, and a plurality of terminal connection holes having a diameter into which the assembled battery positive electrode terminal 22 can be inserted or press-fitted are processed. The terminal connection holes are processed at a pitch equal to the pitch between the assembled battery positive terminals 22 of the stacked assembled battery 20, and the terminal connection holes are similarly processed in the external connection negative terminal 32. Yes.
[0037]
Further, an insulating cover 33 made of an insulating material is provided so as to cover all the connected assembled

battery terminals

22 and 23 so that the assembled

battery terminals

22 and 23 are not exposed to the outside of the composite assembled battery 30. ing. In FIG. 9, the insulating cover 33 is drawn as a perspective view for convenience of explanation, and is not shown in FIG. Then, the six assembled batteries 20 stacked as described above are connected to both side surfaces by flat connecting members 34 and further fastened and fixed by fixing screws 35.
[0038]
As described above, it is required that a battery pack is formed in units of a predetermined number of thin batteries, and further a battery pack is combined with a predetermined number of battery packs in units of the battery pack. It becomes possible to easily obtain a composite battery pack suitable for capacity, voltage and the like. In addition, since the composite battery pack is configured without complicated connection, the failure rate of the composite battery pack due to poor connection can be reduced. Furthermore, when one thin battery constituting the composite assembled battery fails or deteriorates and the thin battery needs to be replaced, the assembled battery having the thin battery can be easily replaced.
[0039]
FIG. 11 is a schematic diagram illustrating an example in which the above-described composite assembled battery 30 is mounted on the vehicle 1 below the floor. As the vehicle 1 moves, a lot of vibration is generated in the vehicle. As shown in the figure, when the above-described composite assembled battery 30 is mounted on the vehicle, the possibility of interface peeling between the terminals of the thin battery and the battery exterior member due to the vibration is significantly reduced. It can be used effectively.
[0040]
The number of thin batteries constituting the assembled battery, the number of assembled batteries constituting the composite battery, the connection method of the thin batteries constituting the assembled battery, and the connection method of the assembled batteries constituting the composite battery are described above. The number and connection method are not limited, and the number and connection method (series connection, parallel connection, series-parallel composite connection) can be appropriately set based on required electric capacity, voltage, and the like.
[0041]
Second embodiment
FIG. 12 is an enlarged cross-sectional view of the terminal lead-out portion of the thin battery according to the second embodiment of the present invention. FIG. 12 corresponds to an enlarged cross-sectional view of a portion III in FIG. In the thin battery 10 according to the second embodiment of the present invention, the

adhesive layers

106d and 107d are newly added to the

battery exterior members

106 and 107 of the first embodiment, and the other components of the thin battery 10 are as follows. This is the same as in the first embodiment.
[0042]
As shown in FIG. 12, an adhesive layer 106d is newly provided between the first resin layer 106a and the metal layer 106b of the upper battery exterior member 106. Similarly, an adhesive layer 107d is newly provided between the first resin layer 107a and the metal layer 107b of the lower battery exterior member 107. By forming a resin layer in which the adhesive layer 106d is very weak, the dynamic spring characteristics of the first resin layer 106a and the metal layer 106b as a dynamic vibration absorber are efficiently reduced. Similarly, the adhesive layer 107d efficiently reduces dynamic spring characteristics as a dynamic vibration absorber between the first resin layer 107a and the metal layer 107b.
[0043]
Using the thin battery according to the second embodiment as a unit battery, an assembled battery in which a plurality of the thin batteries are connected, a composite assembled battery in which a plurality of the assembled batteries are connected, and the composite assembled battery, as in the first embodiment. It can be mounted on a vehicle.
[0044]
Third embodiment
13 is an enlarged cross-sectional view of a terminal lead-out portion according to the third embodiment of the present invention, FIG. 14 is a mass-spring system model of the terminal lead-out portion of FIG. 13, and FIG. 15 is a third embodiment of the present invention. It is a graph which shows the vibration transmissibility spectrum in the terminal derivation | leading-out part which concerns on. FIG. 13 corresponds to an enlarged cross-sectional view of a portion III in FIG.
[0045]
In the thin battery 10 according to the third embodiment of the present invention, a third resin layer 106e is additionally provided between the metal layer 106b and the first resin layer 106a of the battery exterior member 106 of the first embodiment. Similarly, a third resin layer 107e is further provided between the metal layer 107b and the first resin layer 107a of the lower battery exterior member 107, and the other components of the thin battery 10 are the first This is the same as the embodiment. Note that the

first resin layers

106a and 107a of the

battery exterior members

106 and 107 may be seal films disposed only in the vicinity of the positive electrode terminal and the negative electrode terminal.
[0046]
The relationship of the Young's modulus of the three

resin layers

106c, 106a, 106e of the upper battery exterior member 106 is that the Young's modulus of the first resin layer 106a is 5 to 55% with respect to the Young's modulus of the second resin layer, The relationship is such that the Young's modulus of the third resin layer 106e is 90 to 100% with respect to the Young's modulus of the first resin layer 106b. Similarly, the relationship of the Young's modulus of the three

resin layers

107c, 107a, 107e of the lower battery exterior member 107 is such that the Young's modulus of the first resin layer 107a is 5 to 55 with respect to the Young's modulus of the second resin layer 107c. The Young's modulus of the third resin layer 107e is 90% to 100% with respect to the Young's modulus of the first resin layer 107a.
[0047]
And the 3rd resin layer 106e of the upper battery exterior member 106 is connected in series with the 1st resin layer 106a, and as shown in FIG. 14, new 1st spring part K 'and damping element C' are formed. . Similarly, the third resin layer 107e of the lower battery exterior member 107 is connected in series with the first resin layer 107a to form a new first spring portion K ′ and damping element C ′ as shown in FIG. To do. In the mass-spring system model of the terminal lead-out part 111, the

first resin layer

106a, 107a and the

metal layer

106b, 107b are formed by forming a new first spring part K ′ and damping element C ′ connected in series. This effectively reduces the dynamic spring characteristics as a dynamic vibration absorber.
[0048]
In particular, by setting the Young's modulus of the

third resin layers

106e and 107e to be 90 to 100% with respect to the Young's modulus of the

first resin layers

106a and 107a, the movement of the terminal lead-out portion 111 in the mass spring system. It is possible to prevent the unidirectional spring characteristic from being unilaterally dependent on the resin layer having a low Young's modulus, and to easily shift the resonance frequency in the terminal lead-out portion.
[0049]
FIG. 15 shows the vibration transmissibility which is the ratio of the excitation amplitude to the response amplitude on the vertical axis and the frequency transmissibility spectrum of the frequency on the horizontal axis in the terminal lead-out portion of the thin battery according to the third embodiment. As shown in the figure, for example, when a thin battery is used in a vehicle or the like in which the main vibration frequency is particularly concentrated to about 100 Hz or less, the tuning of the terminal lead-out unit is performed by tuning according to the third embodiment of the present invention. By shifting the resonance frequency to about 100 Hz or more and moving away from the vibration frequency, resonance with respect to vibration can be prevented and the thin battery can be used effectively. The vibration frequency is not particularly limited to about 100 Hz or less, and the above tuning can be performed for vibration frequencies higher than that.
[0050]
Using the thin battery according to the third embodiment as a unit battery, similarly to the first embodiment, an assembled battery in which a plurality of the thin batteries are connected, a composite assembled battery in which a plurality of the assembled batteries are connected, and the composite assembled battery. It can be mounted on a vehicle.
[0051]
The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[0052]
【Example】
Hereinafter, the effects of the present invention were confirmed by examples and comparative examples that further embody the present invention. The following examples are for confirming the effects of the thin battery used in the above-described embodiment.
[0053]
Example 1
The thin battery of Example 1 has an aluminum (Al) foil having a thickness of 100 μm as a positive electrode terminal, a copper (Cu) foil having a thickness of 100 μm as a negative electrode terminal, and lithium manganate (LiMnO as a positive electrode active material).₂), An amorphous carbon material was used as the negative electrode active material, and a mixed solution of propylene carbonate (PC) and ethyl methyl carbonate (EMC) was used as the electrolyte. Further, as shown in FIG. 2, a polyethylene (PE) resin film having a film thickness of 80 μm is formed on the first resin layer, an aluminum (Al) foil having a film thickness of 40 μm is formed on the metal layer, and a nylon resin film having a film thickness of 20 μm is formed on the second resin layer. A thin battery having a length of 140 mm, a width of 80 mm, and a thickness of 4 mm was produced using the polymer metal composite film laminated on the upper battery outer member and the lower battery outer member. The Young's modulus of the polyethylene resin film of the first resin layer is 0.08 × 10^-10N / m²The Young's modulus of the nylon resin film of the second resin layer is 0.25 × 10^-10N / m²It is. Therefore, the ratio of the Young's modulus of the first resin layer to the Young's modulus of the second resin layer is 32%, and the thickness of the positive electrode terminal and the negative electrode terminal is 2.5 times the film thickness of the metal layer. became. Table 1 shows the conditions of the thin battery produced in Example 1.
[0054]
[Table 1]

[0055]
The thin battery was measured for acceleration ratio and average attenuation rate. The acceleration ratio was measured by measuring the acceleration value of the response vibration obtained when an acceleration pickup was set at the approximate center of the terminal of the thin battery and subjected to forced excitation at 10 Hz, 50 Hz, and 100 Hz, respectively. At this time, the acceleration ratio was calculated by calculating the ratio based on the acceleration value for the comparative example. In addition, the reference | standard with respect to Example 1 is the comparative example 1 mentioned later. When the acceleration ratio is 1.0, it indicates that the absolute values of the acceleration of the example and the comparative example are the same. When the acceleration ratio is 0.0 to 1.0, the acceleration ratio is compulsory. This shows that the response vibration is reduced with respect to the excitation, and the acceleration ratio value of 1.0 or more means that the response vibration is amplified by resonating with the forced vibration.
[0056]
Moreover, the measurement of an average reduction rate measures the above-mentioned acceleration ratio at 10-300 Hz, averages the reduction rate, and it shows that the vibration was reduced entirely, so that a numerical value is large.
[0057]
As a result, as shown in Table 2, the acceleration ratio measurement in Example 1 was 10 Hz: 0.27, 50 Hz: 0.32, 100 Hz: 0.30, and a reduction in vibration was confirmed at each excitation frequency. . Moreover, the measurement of the average reduction rate in Example 1 was about 50%, and the vibration reduction was confirmed as a whole. As shown in FIG. 4, the vibration transmission spectrum of this example is confirmed to have a resonance frequency of about 100 Hz or more, and the first natural frequency of this example is the same as that of Comparative Example 1. The shift amount to the high frequency side with respect to one natural frequency shifted by about 50 Hz.
[0058]
[Table 2]

[0059]
Example 2
The thin battery of Example 2 uses the same positive electrode active material, negative electrode active material, and electrolytic solution as in Example 1, with a positive electrode terminal of 200 μm thick aluminum (Al) foil and a negative electrode terminal of 200 μm thick nickel ( Ni) foil was used. The first resin layer has a polyethylene (PE) film with a thickness of 80 μm, the metal layer has an aluminum (Al) foil with a thickness of 40 μm, the second resin layer has a thickness of 20 μm, and the first resin layer A polymer metal composite film as shown in FIG. 12 in which an adhesive layer of urethane adhesive is provided at the interface between the resin layer and the metal layer is used as an upper battery outer member and a lower battery outer member, 140 mm long × 80 mm wide × thick. A thin battery having a thickness of 4 mm was produced. The Young's modulus of the polyethylene resin film of the first resin layer is 0.08 × 10^-10N / m²The Young's modulus of the nylon resin film of the second resin layer is 0.25 × 10^-10N / m²It is. Therefore, the ratio of the Young's modulus of the first resin layer to the Young's modulus of the second resin layer is 32%, and the thickness of the positive electrode terminal and the negative electrode terminal is 5.0 times the film thickness of the metal layer. became. Table 1 shows the conditions of the thin battery produced in Example 2.
[0060]
For this thin battery, acceleration ratio measurement and average reduction rate measurement were performed under the same conditions as in the first example. As a result, as shown in Table 2, the acceleration ratio measurement is 10 Hz: 0.25, 50 Hz: 0.3, 100 Hz: 0.29 with respect to the reference, and the vibration is reduced at each excitation frequency. confirmed. Moreover, the average reduction rate measurement in Example 2 was about 40%, and a reduction in vibration was confirmed as a whole. Note that the first natural frequency of this example shifted about 60 Hz to the high frequency side with respect to the first natural frequency of Comparative Example 1, and was positioned at about 100 Hz or more.
[0061]
Example 3
For the thin battery of Example 3, the same positive electrode active material, negative electrode active material, and electrolytic solution as in Example 1 were used, an aluminum (Al) foil having a thickness of 100 μm for the positive electrode terminal, and iron (100 μm thickness for the negative electrode terminal). Fe) foil was used. The first resin layer has a modified polypropylene (PP) thickness of 40 μm, the metal layer has a thickness of 50 μm aluminum (Al) foil, the second resin layer has a thickness of 25 μm nylon resin film, and the first resin A polymer metal composite film in which a third resin layer of a polypropylene (PP) resin film having a film thickness of 40 μm is laminated between the metal layer and the metal layer as shown in FIG. 13 is used as the upper battery outer member and the lower battery outer member. Thus, a thin battery having a length of 140 mm, a width of 80 mm, and a thickness of 4 mm was produced. Table 1 shows the conditions of the thin battery produced in Example 3. The Young's modulus of the modified polypropylene of the first resin layer is 0.12 × 10^-10N / m²The Young's modulus of the nylon resin film of the second resin layer is 0.25 × 10^-10N / m²The Young's modulus of the polypropylene of the third resin layer is 0.13 × 10^-10N / m²It is. Therefore, the ratio of the Young's modulus of the first resin layer to the Young's modulus of the second resin layer is 48%, and the ratio of the Young's modulus of the third resin layer to the Young's modulus of the first resin layer is about 92%. The thicknesses of the positive electrode terminal and the negative electrode terminal were 2.0 times the thickness of the metal layer. The conditions of the thin battery produced in Example 3 are shown in Table 1.
[0062]
For this thin battery, acceleration ratio measurement and average reduction rate measurement were performed under the same conditions as in the first example. As a result, as shown in Table 2, in the acceleration ratio measurement, 10 Hz: 0.30, 50 Hz: 0.35, 100 Hz: 0.34 with respect to the reference, and the vibration is reduced at each excitation frequency. confirmed. Moreover, the average reduction rate measurement in Example 3 was about 45%, and a reduction in vibration was confirmed as a whole. As shown in FIG. 15, the vibration transmission spectrum of this example is confirmed to have a resonance frequency of 100 Hz or more, and the first natural frequency of this example is the first of the first comparative example. The resonance frequency shifted to the high frequency side by about 40 Hz.
[0063]
Example 4
The thin battery of Example 4 uses an aluminum (Al) foil with a thickness of 250 μm for the positive electrode terminal and a nickel (Ni) foil with a thickness of 250 μm for the negative electrode terminal, and other components are the same as in Example 3. A thin battery having a length of 140 mm, a width of 80 mm, and a thickness of 4 mm was produced. Table 1 shows the conditions of the thin battery produced in Example 4.
[0064]
For this thin battery, acceleration ratio measurement and average reduction rate measurement were performed under the same conditions as in the first example. As a result, as shown in Table 2, in the acceleration ratio measurement, 10 Hz: 0.27, 50 Hz: 0.32, 100 Hz: 0.33 with respect to the reference, and it was confirmed that the vibration was reduced at each excitation frequency. It was done. Moreover, the average reduction rate measurement in Example 4 was about 50%, and the reduction of vibration was confirmed as a whole. In addition, the 1st resonance frequency of the present Example shifted about 80 Hz to the high frequency side with respect to the 1st resonance frequency of the comparative example 2, and was located in 100 Hz or more.
[0065]
Comparative Example 1
The thin battery of Comparative Example 1 has a film thickness of 20 μm and a Young's modulus of 0.12 × 106 on the second resin layer of the battery exterior member.^-10N / m²The other components of the thin battery are the same as in Example 1. The ratio of the Young's modulus of the first resin layer to the Young's modulus of the second resin layer is about 67%.
[0066]
Comparative Example 2
The thin battery of Comparative Example 2 has a film thickness of 25 μm and a Young's modulus of 0.12 × 10 6 on the second resin layer of the battery exterior member.^-10N / m²The other components of the thin battery are the same as in Example 3. The ratio of the Young's modulus of the first resin layer to the Young's modulus of the second resin layer is about 92%.
[0067]
Consideration
The first to fourth examples and the first and second comparative examples are compared to shift the resonance frequency away from the excitation frequency, and it is confirmed that vibration is reduced at the entire frequency. It has been found that the battery has a strong structure against applied vibration.
[Brief description of the drawings]
FIG. 1A is a plan view showing an entire thin battery according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line II-II in FIG.
FIG. 2 is an enlarged cross-sectional view of a portion III in FIG.
FIG. 3 is a mass spring system model of the terminal lead-out portion of FIG.
FIG. 4 is a graph showing a vibration transmissibility spectrum at a terminal derivation unit according to the first embodiment of the present invention.
5A and 5B are diagrams showing a connection structure of a plurality of thin batteries according to the first embodiment of the present invention. FIG. 5A shows parallel connection, and FIG. 5B shows serial connection for comparison. Show.
6A and 6B are diagrams showing another connection structure of a plurality of thin batteries according to the first embodiment of the present invention, in which FIG. 6A shows parallel connection, and FIG. 6B is a series for comparison. Indicates a connection.
FIG. 7 is a perspective view of an assembled battery including a plurality of thin batteries according to the first embodiment of the present invention.
8A is a plan view of the assembled battery of FIG. 7, FIG. 8B is a front view of the assembled battery of FIG. 7, and FIG. 8C is a side view of the assembled battery of FIG. .
FIG. 9 is a perspective view of a composite assembled battery including the assembled battery of FIG.
10A is a plan view of the composite battery pack of FIG. 9, FIG. 10B is a front view of the composite battery pack of FIG. 9, and FIG. 10C is a side view of the composite battery pack of FIG. FIG.
FIG. 11 is a schematic view of the composite battery pack according to the first embodiment of the present invention mounted on a vehicle.
FIG. 12 is an enlarged cross-sectional view of a terminal lead-out portion according to a second embodiment of the present invention.
FIG. 13 is an enlarged cross-sectional view of a terminal lead-out portion according to a third embodiment of the present invention.
14 is a mass spring system model of FIG. 13;
FIG. 15 is a graph showing a vibration transmissibility spectrum in a terminal derivation unit according to a third embodiment of the present invention.
[Explanation of symbols]
1 ... Vehicle
10 ... Thin battery
10a: first thin battery
10b ... second thin battery
101 ... Positive electrode plate
102 ... Separator
103 ... Negative electrode plate
104: Positive terminal
105 ... Negative terminal
106: Upper battery exterior member
106c ... second resin layer
106b ... metal layer
106a ... 1st resin layer
106d ... Adhesive layer
106e ... third resin layer
107 ... Lower battery exterior member
107c ... second resin layer
107b ... metal layer
107a ... first resin layer
107d ... Adhesive layer
107e ... third resin layer
109 ... Power generation element
110 ... heat fusion region
111 ... Terminal lead-out part
20 ... Battery
21a ... first bus bar
21b ... second bus bar
22 ... Positive electrode terminal for battery pack
23 ... Negative electrode terminal for battery pack
24 ... Filler
25 ... Battery cover
26. External elastic body
30 ... Composite battery pack
31 ... Positive terminal for external connection
32 ... Negative terminal for external connection
33 ... Insulation cover
34. Connecting member
35 ... Fixing screw

Claims

A sealing means formed by fusing the outer peripheral edges of two exterior members having at least one metal layer sandwiched between two synthetic resin layers;
A power generation element comprising a positive electrode plate, a separator, a negative electrode plate, and an electrolyte is sealed in the sealing means, and a positive electrode terminal connected to the positive electrode plate and a negative electrode terminal connected to the negative electrode plate are the sealing means. A thin battery derived from the edge of the outer periphery of the
Top first synthetic resin layer located in the inner layer is a thin battery having a smaller Young's modulus than the Young's modulus of the second synthetic resin layer located on the outermost layer of the outer member of the outer member.

The thin battery according to claim 1, wherein the second synthetic resin layer has the thinnest film thickness among the synthetic resin layer and the metal layer of the exterior member .

The thin battery according to claim 1 or 2, wherein the first synthetic resin layer has a Young's modulus of 5 to 55% with respect to the Young's modulus of the second synthetic resin layer.

The thin battery according to any one of claims 1 to 3, wherein the positive electrode terminal and the negative electrode terminal have a thickness of 2 to 5 times the thickness of the metal layer.

The thin battery according to claim 1, further comprising an adhesive layer between the metal layer and the first synthetic resin layer.

The thin battery according to claim 1, wherein the exterior member further includes a third resin layer between the metal layer and the first synthetic resin layer.

The thin battery according to claim 6, wherein the third synthetic resin layer has a Young's modulus of 90 to 100% with respect to the Young's modulus of the first synthetic resin layer.

The thin battery according to any one of claims 1 to 7, wherein the first synthetic resin layer includes a material selected from the group consisting of polypropylene, modified polypropylene, polyethylene, modified polyethylene, and ionomer.

The thin battery according to claim 1, wherein the positive electrode terminal includes one or more components selected from the group consisting of aluminum, copper , and nickel.

The thin battery according to any one of claims 1 to 9, wherein the negative electrode terminal includes one or more components selected from the group consisting of iron, nickel, and copper.

The thin battery according to any one of claims 1 to 10, having a thickness of 1 to 10 mm.

Having a positive electrode active material that functions as a positive electrode;
The thin battery according to claim 1, wherein the positive electrode active material is a lithium composite oxide.

The thin battery according to claim 12, wherein the lithium composite oxide is a lithium-manganese composite oxide.

Having a negative electrode active material that functions as a negative electrode;
The thin battery according to claim 1, wherein the negative electrode active material is a carbon-based material.

The thin battery according to claim 14, wherein the carbon-based material is an amorphous carbon material.

Ω in the following formula (1) _１1 And ω _２2 The thin battery according to claim 1, which has a frequency of 100 Hz or more.

However, in the above formula (1), ω _１1 <Ω _２2 , A = (k _１1 + K _２2 ) / M _１1 , B = k _２2 / M _１1 , C = k _２2 / M _２2 And ω _１1 Is the primary natural frequency of the terminal lead-out part derived from the positive electrode terminal or the negative electrode terminal from the sealing means, ω _２2 Is the secondary natural frequency of the terminal lead-out part, m _１1 Is the mass of the positive terminal or negative terminal, m _２2 Is the mass of the metal layer of the exterior member, k _１1 Is the Young's modulus of the first synthetic resin layer, k _２2 Is the Young's modulus of the second synthetic resin layer.

A plurality of thin batteries for electrically connecting the thin battery according to claim 1-16,
A battery assembly comprising: a plurality of connection means for electrically connecting one of a positive electrode terminal or a negative electrode terminal of one thin battery and one of the same-polarity terminal or other-polar terminal of the other thin battery; ,
The other thin battery is juxtaposed on the side of the one thin battery so that the positive electrode terminal of the one thin battery and the same polarity terminal of the other thin battery are in the same direction,
The one connecting means electrically connects the positive terminal of the one thin battery and the same polarity terminal of the other thin battery,
An assembled battery including at least two or more thin batteries in which the negative terminal of the one thin battery and the same-polarity terminal of the other thin battery are electrically connected by another connection means.

An assembled battery having a plurality of thin batteries electrically connected to the thin batteries according to any one of claims 1 to 16 ,
Laminating the other thin battery on the upper part in the vertical direction of the one thin battery so that the positive electrode terminal of the one thin battery and the same polarity terminal of the other thin battery are in the same direction,
Electrically connecting the positive terminal of the one thin battery and the same polarity terminal of the other thin battery;
An assembled battery including at least two or more thin batteries in which a negative electrode terminal of the one thin battery and a homopolar terminal of the other thin battery are electrically connected.

A composite assembled battery comprising a plurality of assembled batteries obtained by electrically connecting the assembled batteries according to claim 17 or 18 in series, parallel connection, or series-parallel composite connection .

A vehicle on which the composite battery pack according to claim 19 is mounted.