JP3596420B2

JP3596420B2 - Non-aqueous electrolyte secondary battery

Info

Publication number: JP3596420B2
Application number: JP2000114886A
Authority: JP
Inventors: 佑治大竹; 文晴阪下; 英明吉尾
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-04-17
Filing date: 2000-04-17
Publication date: 2004-12-02
Anticipated expiration: 2020-04-17
Also published as: JP2001297748A

Description

【０００１】
【発明の属する技術分野】
本発明は、薄い樹脂フィルム主体のラミネートシートで袋状外装ケースを構成し、これで扁平な電池要素を包みこんだ非水電解質二次電池に関するもので、さらに詳しくは、気密、液密性と短絡防止機能に優れたリードを用いた非水電解質二次電池に関するものである。
【０００２】
【従来の技術】
近年、ノートパソコン、携帯電話等のコードレス機器が普及するに伴い、それらの電源として、より小型で高エネルギー密度を有し、繰り返し充放電が可能である高性能のリチウムイオン二次電池が要望されるようになってきた。
【０００３】
このようなリチウムイオン二次電池としては、ＬｉＭＯ_２（ＭはＣｏ、Ｍｎ、Ｎｉ等の遷移金属）を活物質とした正極とリチウムを吸蔵、放出できる易黒鉛化炭素を活物質とした負極板をセパレータを介して構成される電池要素を非水電解液と共に金属ケースに収納したものが知られている。
【０００４】
また、これらを用いた機器の小型化、薄型化が進むに従い、円筒型よりも体積効率が高く、薄型化が可能な角型リチウムイオン電池の需要が増加しているが、特開平３−６２４４７号公報に開示されているように、更なる電池の薄型化のために、外装ケースに従来の金属ケースに代わり、電池要素に接する内側から樹脂接着層、金属箔層、樹脂表面層からなる、いわゆる金属箔を樹脂層で挟みこみ積層一体化したラミネートフィルムを使用する方法が開示されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、ラミネートフィルムを電池の外装ケースとして使用する場合、極板群と外装ケースを直接導通させ、ケース自体を電極として使用する従来のアルミニウム製ケースと異なり、構造上、外装ケースを外部接続端子とすることが困難であり、極板群からそれぞれアルミニウム、銅、ニッケル等の金属製のリード端子を電池外部に取り出す方法が採用されているが、熱溶着時にリード端子と金属箔層とが短絡するといった課題があった。
【０００６】
このリード端子と金属箔層との短絡を防止する方法として、外装ケースのシール部と接するリード表面を絶縁処理する方法が、特開平１０−２８９６９６号公報に開示されているが、リード端子と外装ケースの金属箔層との短絡防止機能と、リード端子と外装ケース内面との気密性、液密性が不十分である。
【０００７】
本発明は、気密、液密性と短絡防止機能に優れたリードを用いた非水電解質二次電池を提供することを主たる目的とする。
【０００８】
【課題を解決するための手段】
上記の課題を解決するための本発明は、それぞれシート状またはフィルム状の正極板、電解質を保持するセパレータおよび負極板を積層した扁平な電池要素を、樹脂フィルム主体のラミネートシートで形成された袋状外装ケース内に収納するとともに、前記正極板および負極板にそれぞれ一端が接続された正極リード及び負極リードを、前記外装ケースのシール部より外部に引き出した電池において、少なくとも前記外装ケースのシール部と接するリード表面が酸変性オレフィン樹脂製の金属接着性樹脂層、高融点樹脂層、低融点接着性樹脂層を順に積層一体化されたリードを用いることにより、気密、液密性と短絡防止機能に優れた非水電解質二次電池を提供するものである。
【０００９】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照しながら説明する。
【００１０】
図１および図２は本発明の非水電解質二次電池の上面図および断面図である。正極１は正極活物質と導電剤および結着剤兼電解液保持剤としてのポリマーを有機溶媒に混練分散したペーストをＡｌ箔製集電体２の両面に塗着、乾燥、圧延し、正極合剤層３としたものである。この２枚の正極の間に、前記ポリマーからなるセパレ−タ９を介してリチウムを吸蔵、放出できる易黒鉛化炭素と前記結着剤兼電解液保持剤としてのポリマーを有機溶媒に混練分散したペーストをＣｕ箔製集電体６に塗着、乾燥、圧延し、負極合剤層７を形成した負極５を配設し、全体が図２に示すように積層されて電池要素１０が構成される。４は正極の集電部に設けたリード取り付け部であり、ここには正極リード１１が溶接されている。８は負極の集電部に設けたリード取り付け部であり、ここには負極リード１２が溶接されている。
【００１１】
図３は本発明の正極リード１１、負極リード１２の詳細断面図である。２３、２４はそれぞれＡｌ箔、Ｃｕ箔で、２０、２１、２２はその両外側に順に配設された金属接着性樹脂層、高融点樹脂層、低融点接着性樹脂層であり、これらは積層一体化されている。
【００１２】
金属接着性樹脂層２０は、Ａｌ箔２３及びＣｕ箔２４との密着性が要求されるために、厚みが２〜１５μｍの酸変性処理、特にマレイン酸処理されたオレフィン樹脂が好ましく、融点が１００℃〜１５０℃のものが最適である。高融点樹脂層２１は、リードと外装ケースの金属箔との短絡防止性が要求されるために厚みが２０〜５０μｍのポリエチレン樹脂やポリプロピレン樹脂等のポリオレフィン樹脂、これらの共重合体や酸変性されたものが好ましい。低融点接着性樹脂層２２は、外装ケース１３の内面との密着性が要求されるために、厚みが２〜１５μｍのポリエチレン樹脂やポリプロピレン樹脂等のポリオレフィン樹脂、これらの共重合体や酸変性されたものが好ましく、外装ケースの金属箔との短絡防止性から高融点樹脂層２１よりも融点が３０℃以上低い樹脂層であることが好ましい。
【００１３】
発電要素１０を内部に収納する外装ケース１３は、電解液、水のバリアー性が要求されるために２０〜５０μｍのアルミニウム製箔からなる金属箔層の外側に、耐電解液性、機械的強度が要求されるために厚さが１０μｍ〜５０μｍのポリアミド（ナイロン）樹脂層、内側に熱溶着性とリードとの短絡防止性が要求されるためにポリエチレン樹脂やポリプロピレン樹脂等のポリオレフィン樹脂、これらの共重合体や酸変性された樹脂層からなる外装ケースが好ましい。
【００１４】
発電要素１０を外装ケース１３の内部に収納した後、外装ケース１３の開口部より所定量の電解液注入した後に、熱溶着により封口される。
【００１５】
【実施例】
本発明を実施例、比較例を用いて詳しく説明する。
【００１６】
（実施例１）
正極１は活物質であるＬｉＣｏＯ_２と導電剤としてアセチレンブラック、および結着剤兼電解液保持剤としてのポリマーであるフッ化ビニリデン（ＶＤＦ）とヘキサフルオロプロピレン（ＨＦＰ）との共重合体Ｐ（ＶＤＦ−ＨＦＰ）をＮＭＰ（Ｎ−メチル−２−ピロリドン）からなる有機溶媒に混練分散したペーストをラス加工したＡｌ箔製集電体２に塗着、乾燥、圧延して、正極合剤層３としたものである。この２枚の正極の間に、前記Ｐ（ＶＤＦ−ＨＦＰ）のフィルムからなるセパレ−タ９を介してリチウムを吸蔵、放出できる易黒鉛化炭素と前記Ｐ（ＶＤＦ−ＨＦＰ）の粉末をアセトンとシクロヘキサノンからなる混合有機溶媒に混練分散したペーストをＣｕ箔製集電体６に塗着、乾燥、圧延して、負極合剤層７を形成した負極５を配設し、全体が図２に示すように積層されて電池要素１０が構成される。４は正極の集電部に設けたリード取り付け部であり、ここには外装ケースのシール部と接する箇所に、融点が１３８℃で厚さが１０μｍのマレイン酸変性ポリプロピレン樹脂からなる金属接着性樹脂層２０、融点が１７０℃で厚さが３２μｍのポリエチレン−ポリプロピレン共重合体からなる高融点樹脂層２１、融点が１１８℃で厚さが４μｍのポリエチレン樹脂からなる低融点接着性樹脂層２２であり、これらを積層一体化した樹脂層で被覆されているＡｌ箔製正極リード１１が溶接されている。８は負極の集電部に設けたリード取り付け部であり、ここにもＡｌ箔製正極リード１１と同様の金属接着性樹脂層２０、高融点樹脂層２１、低融点接着性樹脂層２２を順に積層一体化した樹脂層で被覆されているＣｕ製負極リード１２が溶接されている。
【００１７】
これらのリードを有する電池要素１０を外装ケース１３の内部に収納した後、外装ケース１３の開口部よりエチレンカーボネートとエチルメチルカーボネートを体積比１：３の混合溶媒にＬｉＰＦ_６を１〜１．５モル／ｌ溶解した電解液を所定量を注入した後に、熱溶着により封口して、非水電解質二次電池を作製した。
【００１８】
（実施例２）
金属接着性樹脂層２０に融点が１５０℃で厚さ１０μｍのマレイン酸変性ポリプロピレン樹脂、高融点樹脂層２１に融点が１７５℃で厚さ２６μｍのポリエチレン−ポリプロピレン共重合体、低融点接着性樹脂層２２に融点が１３８℃で厚さ４μｍのポリエチレン−ポリプロピレン共重合体を用いた以外は実施例１と同様にして非水電解質二次電池を作製した。
【００１９】
（比較例１）
低融点接着樹脂層２２に融点が１１８℃で厚さ４０μｍのポリエチレン樹脂、金属接着性樹脂層２０にはマレイン酸変性していないポリプロピレン樹脂を設けた以外は実施例１と同様にして非水電解質二次電池を作製した。
【００２０】
（比較例２）
金属接着性樹脂層２０に融点が１３８℃で厚さ４μｍのマレイン酸変性ポリプロピレン樹脂、高融点樹脂層２１には何も設けなかった以外は実施例１と同様にして非水電解質二次電池を作製した。
【００２１】
実施例１、実施例２、比較例１、比較例２で得られた電池を各２０セル用意して、気密性、液密性と短絡防止性を評価した。
【００２２】
気密性、液密性の評価は、温度６０℃、湿度９０％の恒温恒湿中に１０００時間放置した場合のふくれ量を測定し、ふくれ量が初期厚みの１０％を超えるものを気密性、液密性ＮＧと判定した。
【００２３】
短絡防止性の評価はアルミニウム箔層の端面と正極リード端子間の電圧を測定し、電圧の有無で短絡の有無を判定した。短絡していない場合は０Ｖである。
【００２４】
【表１】

【００２５】
表１から高融点樹脂層のない比較例１の場合は、熱溶着時に金属箔層とリード端子間の電圧が発生し短絡したものが１２／２０個発生した。また、低融点接着樹脂層がない比較例２の場合は、低融点接着層と外装ケースの内側の界面から水分が侵入し、電池要素と反応したふくれが１０／２０個発生した。これに対して、実施例１、実施例２の場合は、気密性、液密性と短絡防止機能に優れていることが明らかになった。
【００２６】
【発明の効果】
以上の説明のとおり本発明の薄い樹脂フィルム主体のラミネートシートからなる袋状外装ケースを有する非水電解質二次電池によれば、少なくとも袋状外装ケースのシール部と接するリード表面が酸変性オレフィン樹脂製の金属接着性樹脂層、高融点樹脂層、低融点接着性樹脂層を順に積層一体化されたリードを用いることにより、気密性、液密性と短絡防止機能の両方に優れた非水電解質二次電池を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態における電池の上面図
【図２】同電池の断面図
【図３】本発明の一実施形態におけるリードの詳細断面図
【符号の説明】
１正極
２正極集電体
３正極合剤層
４正極リード取り付け部
５負極
６負極集電体
７負極合剤層
８負極リード取り付け部
９セパレータ
１０電池要素
１１正極リード
１２負極リード
１３外装ケース
２０金属接着性樹脂層
２１高融点樹脂層
２２低融点接着性樹脂層
２３Ａｌ箔
２４Ｃｕ箔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-aqueous electrolyte secondary battery in which a bag-shaped outer case is formed of a laminate sheet mainly composed of a thin resin film, and which wraps a flat battery element, and more specifically, airtightness and liquid tightness. The present invention relates to a non-aqueous electrolyte secondary battery using a lead having an excellent short-circuit prevention function.
[0002]
[Prior art]
In recent years, with the spread of cordless devices such as notebook computers and mobile phones, there has been a demand for a high-performance lithium-ion secondary battery having a smaller size, a higher energy density, and capable of being repeatedly charged and discharged as a power source for such devices. It has come to be.
[0003]
As such a lithium ion secondary battery, a positive electrode using LiMO ₂ (M is a transition metal such as Co, Mn, Ni, etc.) as an active material and a negative electrode plate using an easily graphitizable carbon capable of occluding and releasing lithium as an active material. Is known in which a battery element configured with a non-aqueous electrolyte is accommodated in a metal case via a separator.
[0004]
Further, with the progress of miniaturization and thinning of devices using these devices, there is an increasing demand for prismatic lithium ion batteries which have higher volumetric efficiency than cylindrical types and which can be made thinner. As disclosed in Japanese Patent Application Publication, for further thinning the battery, instead of a conventional metal case for the outer case, a resin adhesive layer, a metal foil layer, and a resin surface layer are formed from the inside in contact with the battery element, There is disclosed a method of using a laminated film in which a so-called metal foil is sandwiched between resin layers and laminated and integrated.
[0005]
[Problems to be solved by the invention]
However, when the laminate film is used as an outer case of the battery, the electrode group and the outer case are directly connected to each other, and unlike the conventional aluminum case that uses the case itself as an electrode, the outer case is structurally connected to the external connection terminal. Although it is difficult to remove the lead terminals made of metal such as aluminum, copper, and nickel from the electrode plate group to the outside of the battery, the lead terminals and the metal foil layer are short-circuited during heat welding. There was such a problem.
[0006]
As a method of preventing a short circuit between the lead terminal and the metal foil layer, a method of insulating the surface of the lead in contact with the sealing portion of the outer case is disclosed in Japanese Patent Application Laid-Open No. Hei 10-289696. The function of preventing short-circuit with the metal foil layer of the case and the airtightness and liquid tightness between the lead terminals and the inner surface of the outer case are insufficient.
[0007]
An object of the present invention is to provide a non-aqueous electrolyte secondary battery using a lead excellent in airtightness, liquid tightness, and short circuit prevention function.
[0008]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems includes a flat battery element in which a sheet-like or film-like positive electrode plate, a separator holding an electrolyte and a negative electrode plate are laminated, and a bag formed of a resin film-based laminate sheet. A battery in which a positive electrode lead and a negative electrode lead each having one end connected to the positive electrode plate and the negative electrode plate, respectively, are drawn out of a seal portion of the outer case while being housed in the outer case. Air-tight, liquid-tight and short-circuit prevention functions by using a lead in which a metal contact resin layer made of an acid-modified olefin resin , a high melting point resin layer, and a low melting point adhesive resin layer are sequentially laminated and integrated. It is intended to provide a non-aqueous electrolyte secondary battery having excellent characteristics.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
1 and 2 are a top view and a cross-sectional view of the non-aqueous electrolyte secondary battery of the present invention. The positive electrode 1 is prepared by applying a paste obtained by kneading and dispersing a positive electrode active material, a conductive agent, and a polymer as a binder and an electrolyte holding agent in an organic solvent to both surfaces of an Al foil current collector 2, drying and rolling. This is the agent layer 3. Between the two positive electrodes, a graphitizable carbon capable of inserting and extracting lithium through a separator 9 made of the polymer and a polymer as the binder and electrolyte retainer were kneaded and dispersed in an organic solvent. The paste is applied to a current collector 6 made of Cu foil, dried and rolled to provide a negative electrode 5 having a negative electrode mixture layer 7 formed thereon, and the whole is laminated as shown in FIG. You. Reference numeral 4 denotes a lead mounting portion provided on the current collecting portion of the positive electrode, to which a positive electrode lead 11 is welded. Reference numeral 8 denotes a lead mounting portion provided on the current collecting portion of the negative electrode, to which a negative electrode lead 12 is welded.
[0011]
FIG. 3 is a detailed sectional view of the positive electrode lead 11 and the negative electrode lead 12 of the present invention. Reference numerals 23 and 24 denote Al foil and Cu foil, respectively, and

reference numerals

20, 21 and 22 denote a metal adhesive resin layer, a high melting point resin layer, and a low melting point adhesive resin layer which are sequentially disposed on both outer sides thereof. It is integrated.
[0012]
Since the metal adhesive resin layer 20 is required to have adhesiveness to the Al foil 23 and the Cu foil 24, an olefin resin having a thickness of 2 to 15 μm, which has been subjected to an acid modification treatment, particularly a maleic acid treatment, is preferably used, and has a melting point of 100 μm. C. to 150.degree. C. are optimal. The high melting point resin layer 21 is required to have a property of preventing short-circuiting between the lead and the metal foil of the outer case, so that a polyolefin resin such as a polyethylene resin or a polypropylene resin having a thickness of 20 to 50 μm, a copolymer thereof, or an acid-modified resin is used. Are preferred. The low-melting-point adhesive resin layer 22 is required to have adhesion to the inner surface of the outer case 13, and therefore has a thickness of 2 to 15 μm, such as a polyolefin resin such as a polyethylene resin or a polypropylene resin, a copolymer thereof, or an acid-modified resin. Preferably, the resin layer is a resin layer having a melting point lower than that of the high-melting resin layer 21 by 30 ° C. or more from the viewpoint of preventing short circuit with the metal foil of the outer case.
[0013]
The outer case 13 accommodating the power generating element 10 has an electrolytic solution resistance and a mechanical strength outside the metal foil layer made of aluminum foil of 20 to 50 μm because of a barrier property of an electrolytic solution and water. Is required, a polyamide (nylon) resin layer having a thickness of 10 μm to 50 μm is required, and a polyolefin resin such as a polyethylene resin or a polypropylene resin is required on the inside because a heat welding property and a short circuit prevention property with a lead are required. An outer case made of a copolymer or an acid-modified resin layer is preferable.
[0014]
After the power generation element 10 is housed inside the outer case 13, a predetermined amount of electrolyte is injected from the opening of the outer case 13, and then sealed by heat welding.
[0015]
【Example】
The present invention will be described in detail using examples and comparative examples.
[0016]
(Example 1)
The positive electrode 1 is made of a copolymer P () of LiCoO _{2 as an} active material, acetylene black as a conductive agent, and vinylidene fluoride (VDF) and hexafluoropropylene (HFP), which are polymers as a binder and an electrolyte retainer. VDF-HFP) is kneaded and dispersed in an organic solvent composed of NMP (N-methyl-2-pyrrolidone), applied to a lath-processed current collector 2 made of Al foil, dried and rolled to form a positive electrode mixture layer 3 It is what it was. Between the two positive electrodes, the graphitizable carbon capable of inserting and extracting lithium through the separator 9 made of the P (VDF-HFP) film and the powder of the P (VDF-HFP) were mixed with acetone. A paste kneaded and dispersed in a mixed organic solvent composed of cyclohexanone was applied to a current collector 6 made of Cu foil, dried and rolled to provide a negative electrode 5 having a negative electrode mixture layer 7 formed thereon. Thus, the battery element 10 is configured. Reference numeral 4 denotes a lead mounting portion provided on the current collecting portion of the positive electrode, in which a metal adhesive resin made of a maleic acid-modified polypropylene resin having a melting point of 138 ° C. and a thickness of 10 μm is provided at a portion in contact with the sealing portion of the outer case. A high melting point resin layer 21 made of a polyethylene-polypropylene copolymer having a melting point of 170 ° C. and a thickness of 32 μm; and a low melting point adhesive resin layer 22 made of a polyethylene resin having a melting point of 118 ° C. and a thickness of 4 μm. A positive electrode lead 11 made of Al foil and covered with a resin layer obtained by laminating and integrating these is welded. Reference numeral 8 denotes a lead mounting portion provided on the current collecting portion of the negative electrode. Here, a metal adhesive resin layer 20, a high melting point resin layer 21, and a low melting point adhesive resin layer 22 similar to the Al foil positive electrode lead 11 are sequentially formed. A Cu negative electrode lead 12 covered with a laminated and integrated resin layer is welded.
[0017]
After the battery element 10 having these leads is housed in the outer case 13, LiPF ₆ is mixed in a mixed solvent of ethylene carbonate and ethyl methyl carbonate at a volume ratio of 1: 3 with LiPF ₆ from 1 to 1.5 through the opening of the outer case 13. After injecting a predetermined amount of the electrolytic solution dissolved in mol / l, the solution was sealed by heat welding to produce a non-aqueous electrolyte secondary battery.
[0018]
(Example 2)
A maleic acid-modified polypropylene resin having a melting point of 150 ° C. and a thickness of 10 μm is formed on the metal adhesive resin layer 20, a polyethylene-polypropylene copolymer having a melting point of 175 ° C. and a thickness of 26 μm is formed on the high melting point resin layer 21, and a low melting point adhesive resin layer A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1, except that a polyethylene-polypropylene copolymer having a melting point of 138 ° C. and a thickness of 4 μm was used in No. 22.
[0019]
(Comparative Example 1)
A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that a polyethylene resin having a melting point of 118 ° C. and a thickness of 40 μm was provided for the low melting point adhesive resin layer 22 and a polypropylene resin not modified with maleic acid was provided for the metal adhesive resin layer 20. A secondary battery was manufactured.
[0020]
(Comparative Example 2)
A non-aqueous electrolyte secondary battery was prepared in the same manner as in Example 1 except that a maleic acid-modified polypropylene resin having a melting point of 138 ° C. and a thickness of 4 μm was provided in the metal adhesive resin layer 20 and nothing was provided in the high melting point resin layer 21. Produced.
[0021]
Twenty cells of each of the batteries obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were prepared, and the airtightness, liquid tightness, and short circuit prevention were evaluated.
[0022]
The airtightness and liquid tightness were evaluated by measuring the amount of blister when left for 1000 hours in a constant temperature and humidity at a temperature of 60 ° C. and a humidity of 90%. It was determined to be liquid tight NG.
[0023]
For the evaluation of short-circuit prevention, the voltage between the end face of the aluminum foil layer and the positive electrode lead terminal was measured, and the presence or absence of the voltage was used to determine the presence or absence of a short circuit. When there is no short circuit, it is 0V.
[0024]
[Table 1]

[0025]
From Table 1, in the case of Comparative Example 1 having no high melting point resin layer, a voltage was generated between the metal foil layer and the lead terminal during thermal welding, and 12/20 short circuits occurred. In the case of Comparative Example 2 having no low-melting-point adhesive resin layer, moisture penetrated from the interface between the low-melting-point adhesive layer and the inside of the outer case, and 10/20 blisters reacted with the battery element were generated. On the other hand, Examples 1 and 2 were found to be excellent in airtightness, liquid tightness and short circuit prevention function.
[0026]
【The invention's effect】
As described above, according to the nonaqueous electrolyte secondary battery having the bag-shaped outer case made of the thin resin film-based laminate sheet of the present invention, at least the lead surface in contact with the seal portion of the bag-shaped outer case has an acid-modified olefin resin. Made in the metal adhesive resin layer, the high melting point resin layer, by using a lead low-melting-point adhesive resin layer are integrally laminated in this order, airtight, non-aqueous electrolyte having excellent both liquid-tightness and short-circuit prevention function A secondary battery can be provided.
[Brief description of the drawings]
FIG. 1 is a top view of a battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the battery. FIG. 3 is a detailed cross-sectional view of a lead according to an embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Positive electrode current collector 3 Positive electrode mixture layer 4 Positive electrode lead attachment part 5 Negative electrode 6 Negative electrode collector 7 Negative electrode mixture layer 9 Negative electrode lead attachment part 9 Separator 10 Battery element 11 Positive electrode lead 12 Negative electrode lead 13 Outer case 20 Metal Adhesive resin layer 21 High melting point resin layer 22 Low melting point adhesive resin layer 23 Al foil 24 Cu foil

Claims

A flat battery element in which a sheet-like or film-like positive electrode plate, a separator holding an electrolyte and a negative electrode plate are laminated, respectively, is housed in a bag-shaped outer case formed of a laminate sheet mainly composed of a resin film, and the positive electrode plate And a battery in which a positive electrode lead and a negative electrode lead each having one end connected to the negative electrode plate are drawn out from the sealing portion of the outer case,
The lead is a lead in which at least a lead surface in contact with a seal portion of the outer case is formed by sequentially laminating and integrating an acid-modified olefin resin metal adhesive resin layer, a high melting point resin layer, and a low melting point adhesive resin layer. Non-aqueous electrolyte secondary battery characterized by the above-mentioned.

The non-aqueous electrolyte secondary battery according to claim 1, wherein a difference in melting point between the high melting point resin layer and the low melting point adhesive resin layer is 30 ° C or more.