JP2952017B2 - Battery separator, method for producing the same, and battery - Google Patents
Battery separator, method for producing the same, and batteryInfo
- Publication number
- JP2952017B2 JP2952017B2 JP2249334A JP24933490A JP2952017B2 JP 2952017 B2 JP2952017 B2 JP 2952017B2 JP 2249334 A JP2249334 A JP 2249334A JP 24933490 A JP24933490 A JP 24933490A JP 2952017 B2 JP2952017 B2 JP 2952017B2
- Authority
- JP
- Japan
- Prior art keywords
- battery
- film
- separator
- molecular weight
- average molecular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Cell Separators (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は電池用セパレータ、その製造法および該セパ
レータを組み込んだ電池に関する。The present invention relates to a battery separator, a method for producing the same, and a battery incorporating the separator.
（従来の技術） 電池用セパレータとしては、正負両極を隔離するとい
う本来の機能を有すると共に、電解液に対する充分な耐
性を備え、更に電池の内部抵抗を増大させることのない
良好なイオン導電性をも備える必要が有る。(Prior Art) As a battery separator, it has an original function of isolating both positive and negative electrodes, has sufficient resistance to an electrolytic solution, and has good ionic conductivity without increasing the internal resistance of the battery. Must also be provided.
電池の種類は多いが、リチウム等を負極とする非水電
解液電池は高エネルギー密度を有すると共に自己放電が
少ないので、近年、大電流用電池として注目されてい
る。Although there are many types of batteries, nonaqueous electrolyte batteries using lithium or the like as a negative electrode have attracted attention as large current batteries in recent years because they have high energy density and low self-discharge.
この非水電解液電池はジメチルフォルムアミド、プロ
ピレンカーボネート、アセトニトリル、ブチロラクト
ン、ジメチルフォルムアミド等の非プロトン溶媒で且つ
誘電率の高い液体にLiPF6、LiCl4、LiClO4、LiBF4等を
電解質として溶解したものを電解液として用いている。This non-aqueous electrolyte battery dissolves LiPF 6 , LiCl 4 , LiClO 4 , LiBF 4 etc. as an electrolyte in a liquid with high a dielectric constant such as dimethylformamide, propylene carbonate, acetonitrile, butyrolactone, dimethylformamide etc. This is used as an electrolyte.
この非水電解液は電気伝導度が低く、従って、大電流
を取り出すために正負両極の面積を可及的に大きくする
必要がある。This non-aqueous electrolyte has a low electric conductivity, so that it is necessary to increase the area of the positive and negative electrodes as much as possible in order to extract a large current.
そのため、非水電解液電池は正負両極を構成する材料
をセパレータを介して重合わせて渦巻状に巻き、該渦巻
状体を金属ケースに収納した構造とされている。Therefore, the non-aqueous electrolyte battery has a structure in which the materials constituting the positive and negative electrodes are superposed and spirally wound via a separator, and the spirally wound body is housed in a metal case.
ところで、大電流用電池にあっては、強制放電等の誤
使用により起因した外部短絡によって異常電流が流れ、
これに伴って内部温度が著しく上昇し、遂には火災や爆
発という重大事故を引き起こす危険性がある。これを回
避するため、電池の構造自体を防爆型とする等の工夫が
種々とられているが、異常電流とこれに伴う発熱を防止
するという観点からは本質的な解決策となっていない。By the way, in a high-current battery, an abnormal current flows due to an external short circuit caused by misuse such as forced discharge,
As a result, the internal temperature rises significantly, and there is a danger of finally causing a serious accident such as a fire or explosion. In order to avoid this, various measures have been taken such as making the structure of the battery itself explosion-proof, but this is not an essential solution from the viewpoint of preventing abnormal current and the accompanying heat generation.
一方、電池用セパレータとして、特公昭46−40119号
公報に記載されているようなポリプロピレン（以下、PP
と称す）製微孔フィルムを用いることが知られている。On the other hand, as a battery separator, polypropylene (hereinafter referred to as PP) as described in JP-B-46-40119 is used.
It is known to use a microporous film.
このPP製微孔フィルムは、常温付近では良好な電気伝
導性を示すが、高温領域では電気抵抗が増大する性質を
有している。従って、これをセパレータとして用いた電
池において異常電流が流れた場合、該電流による発熱の
ために温度が上昇すると電池の内部電気抵抗が増大する
結果、電流遮断機能が発現して危険を回避し得ることも
期待できる。しかしながら、PP製微孔フィルムはかなり
高温、例えば180℃以上とならなければ異常電流を遮断
するに充分な電気抵抗の増大がないことが判明した。This PP microporous film has good electrical conductivity near normal temperature, but has a property of increasing electrical resistance in a high temperature region. Therefore, when an abnormal current flows in a battery using this as a separator, when the temperature rises due to heat generated by the current, the internal electrical resistance of the battery increases, and as a result, a current interrupting function is developed and danger can be avoided. We can expect that. However, it has been found that the PP microporous film does not have a sufficient increase in electrical resistance to interrupt abnormal current unless the temperature is extremely high, for example, 180 ° C. or higher.
本発明者の電池内部に異常電流が流れた場合、より低
温で該電流を遮断しその安全を確保するために種々研究
を行い、粘度平均分子量30万以下のポリエチレン（以
下、PEと称す）と、粘度平均分子量100万以上のPEの混
合物から成る微孔性フィルムを電池用セパレータとして
用いることを先に提案した（特開平２−21559号公
報）。この電池用セパレータはPP製微孔フィルムから成
る従来品に比べ、より低温（例えば、約130℃）におい
て電流遮断機能を示し、安全性が大幅に改善されたもの
となっている。When an abnormal current flows inside the battery of the present inventor, various studies have been conducted to cut off the current at a lower temperature and ensure its safety, and a polyethylene having a viscosity average molecular weight of 300,000 or less (hereinafter, referred to as PE). It has been previously proposed to use a microporous film composed of a mixture of PE having a viscosity average molecular weight of 1,000,000 or more as a battery separator (JP-A-2-21559). This battery separator exhibits a current interruption function at a lower temperature (for example, about 130 ° C.) as compared with a conventional product made of a microporous film made of PP, and has greatly improved safety.
（発明が解決しようとする課題） ところで、非水電解液電池のように両極をセパレータ
を介して渦巻状に巻き、これを金属等のケースに収納す
るタイプの電池の製造に際しては、セパレータが巻回作
業およびケースへの収納作業時に作用する機械的ストレ
スに対する抵抗性を有し破損しないことが生産効率（歩
留り）の点から望ましいものである。(Problems to be Solved by the Invention) By the way, when manufacturing a battery of a type in which both electrodes are spirally wound through a separator like a nonaqueous electrolyte battery and this is housed in a case made of metal or the like, the separator is wound. It is desirable from the point of production efficiency (yield) that it has resistance to mechanical stress that acts during the turning operation and the storing operation in the case and does not break it.
しかしながら、分子量の異なるPEの混合物から成る上
記セパレータは機械的ストレスに対する抵抗性が充分で
ないことがあり、正負両極間に配置して渦巻状に巻回す
る際、あるいは渦巻状体をケースに収納する際に破れた
り、裂けたりすることがあった。However, the separator composed of a mixture of PEs having different molecular weights may not have sufficient resistance to mechanical stress, and may be disposed between the positive and negative electrodes and spirally wound, or the spiral body may be housed in a case. Sometimes it was torn or torn.
従って、本発明は低温での電流遮断機能を維持したま
ま、機械的ストレスに対する抵抗性の優れたセパレータ
を提供することを目的とする。Accordingly, an object of the present invention is to provide a separator having excellent resistance to mechanical stress while maintaining a current interruption function at a low temperature.
（課題を解決するための手段） 本発明者は従来技術の有する上記問題を解決するため
種々研究の結果、特定分子量の２種のPEに更にPPを加え
た混合物を素材として微孔性フィルムが、低温で電流遮
断機能を有すると共に機械的ストレスに対する優れた抵
抗性を示すこと、この微孔性フィルムはPE、PPに対する
良溶媒と貧溶媒を用いる特性手法によって容易に製造し
得ること、および該微孔性フィルムをセパレータとして
用いた電池は安全性に優れていることを知り、本発明を
完成するに至った。(Means for Solving the Problems) The present inventor has conducted various studies to solve the above-mentioned problems of the prior art, and as a result, a microporous film was obtained by using a mixture of two types of PE having a specific molecular weight and further adding PP. Having a current interrupting function at low temperatures and exhibiting excellent resistance to mechanical stress, and that the microporous film can be easily produced by a characteristic method using a good solvent and a poor solvent for PE and PP; and The battery using the microporous film as a separator was found to be excellent in safety, and the present invention was completed.
即ち、本発明の第１は粘度平均分子量30万以下のPE、
粘度平均分子量100万以上のPE、およびPPを必須成分と
する混合物を素材とした微孔性フィルムから成る電池表
セパレータに係るものである。That is, the first of the present invention is PE having a viscosity average molecular weight of 300,000 or less,
The present invention relates to a battery surface separator made of a microporous film made of a mixture containing PE having a viscosity average molecular weight of 1,000,000 or more and PP as an essential component.
また、本発明の第２は次の四つの工程、 （ａ）粘度平均分子量30万以下のPE、粘度平均分子量10
0万以上のPE、およびPPを良溶媒に溶解する工程、 （ｂ）上記工程で得た溶液を用いてフィルム成形する工
程、 （ｃ）上記工程で得たフィルム状物を貧溶媒に浸漬する
工程、 （ｄ）上記浸漬処理後のフィルム状物を延伸する工程、 を含む電池溶セパレータの製造法に係るものである。The second step of the present invention is the following four steps: (a) PE having a viscosity average molecular weight of 300,000 or less, and a viscosity average molecular weight of 10
A step of dissolving more than 100,000 PE and PP in a good solvent, (b) a step of forming a film using the solution obtained in the above step, and (c) immersing the film obtained in the above step in a poor solvent And (d) a step of stretching the film-like material after the immersion treatment.
更に、本発明の第３は正極、負極およびこれら両極間
に介在せしめられたセパレータを有し、このセパレータ
が粘度平均分子量30万以下のPE、粘度平均分子量100万
以上のPE、およびPPを必須成分とする混合物を素材とし
た微孔性フィルムから成ることを特徴とするものであ
る。Further, the third aspect of the present invention has a positive electrode, a negative electrode and a separator interposed between these two electrodes, and the separator is required to have PE having a viscosity average molecular weight of 300,000 or less, PE having a viscosity average molecular weight of 1,000,000 or more, and PP. It is characterized by comprising a microporous film made of a mixture as a component.
本発明において用いられるPEのうちの一方は粘度平均
分子量（粘度法により測定した分子量）30万以下、好ま
しくは1000〜25万程度のものである。この低分子量PEは
温度上昇時の電流遮断機能に貢献するものである。な
お、このPEの密度としては0.90〜0.97、メルトインデッ
クスとしては、0.1〜100g/minのものが好ましい。One of the PEs used in the present invention has a viscosity average molecular weight (molecular weight measured by a viscosity method) of 300,000 or less, preferably about 1,000 to 250,000. This low molecular weight PE contributes to a current interrupting function when the temperature rises. The density of the PE is preferably 0.90 to 0.97, and the melt index is preferably 0.1 to 100 g / min.
また、他方のPEは粘度平均分子量100万以上、好まし
くは120万〜500万程度のものであり、一般に超高分子量
ポリエチレンと呼ばれている（以下、粘度平均分子量10
0万以上のPEをUHPEと称す）。このUHPEの市販品として
は三ツ井石油化学工業社勢の商品名ハイゼックスミリオ
ン、ヘキスト社勢の商品名ホスタレンGUR等がある。そ
して、このUHPEを使用しなければ、正負両極の隔離機能
と電解液に対する耐性を備え、且つ良好なイオン導電性
を示す強靭な微孔性ィルムを得ることが困難となる。The other PE has a viscosity average molecular weight of 1,000,000 or more, preferably about 1.2 million to 5,000,000, and is generally called ultra-high molecular weight polyethylene (hereinafter, referred to as viscosity average molecular weight of 10
More than 100,000 PEs are called UHPE). Commercially available UHPE products include Hi-Zex Million (trade name) of Mitsui Petrochemical Industries, Ltd., and Hostalen GUR (trade name of Hoechst). Unless this UHPE is used, it is difficult to obtain a strong microporous film having a function of isolating both positive and negative electrodes and resistance to an electrolytic solution and exhibiting good ionic conductivity.
本発明において上記分子量の異なるPEおよびUHPEの他
の更にPPを使用する。PPの使用により、正負両極間に配
置して渦巻状に巻回する作業時、あるいは渦巻状体のケ
ースへの収納作業時に破損し難いセパレータが得られ
る。このPPとしては、通常、粘度平均分子量が100万以
下、好ましくは20万〜60万のものが使用される。In the present invention, other PPs other than the above PEs and UHPEs having different molecular weights are used. By using PP, it is possible to obtain a separator which is hardly damaged at the time of the work of being arranged between the positive and negative electrodes and spirally wound, or the work of storing the spiral body in the case. As the PP, those having a viscosity average molecular weight of 1,000,000 or less, preferably 200,000 to 600,000 are used.
本発明においてPE、UHPEおよびPPの混合割合は、混合
物中つまり三者の合計量中に占めるPEの割合が５〜50重
量％好ましくは10〜40重量％、UHPEの割合が10〜90重量
％好ましくは35〜80重量％、PPの割合が５〜40重量％好
ましくは10〜25重量％となるようにするのが良い。PEの
割合が過少では異常電流による温度上昇時における電流
遮断機能が不確実なものとなり易く、逆に過多ではセパ
レータの引張強度の低下を招くことになる。また、PPの
割合が過少では機械的ストレスに対する抵抗性の優れた
セパレータが得られず、逆に過多ではセパレータの引張
強度の低下を招くことになる。In the present invention, the mixing ratio of PE, UHPE and PP is such that the ratio of PE in the mixture, that is, the total amount of the three is 5 to 50% by weight, preferably 10 to 40% by weight, and the ratio of UHPE is 10 to 90% by weight. It is preferable that the content is preferably 35 to 80% by weight and the proportion of PP is 5 to 40% by weight, preferably 10 to 25% by weight. If the proportion of PE is too small, the current interrupting function when the temperature rises due to an abnormal current is likely to be uncertain, while if too large, the tensile strength of the separator will decrease. On the other hand, if the proportion of PP is too small, a separator having excellent resistance to mechanical stress cannot be obtained, and if it is too large, the tensile strength of the separator will decrease.
かようなPE、UHPEおよびPPを素材とする微孔性フィル
ムから成る電池用セパレータは、微孔性フィルムの作製
法として知られる種々の方法で製造できるが、上記した
四つの工程を含む本発明の方法を採用することにより、
容易且つ確実に得ることができる。Such a battery separator made of a microporous film made of PE, UHPE and PP can be produced by various methods known as a method for producing a microporous film, and the present invention includes the above-described four steps. By adopting the method of
It can be obtained easily and reliably.
本発明に係る方法の（ａ）工程において用いる良溶媒
はPE、UHPEおよびPPを溶解乃至膨潤（以下、本発明にお
いて「溶解」とは「溶解乃至膨潤」を総称する意味で用
いる）させ得るものであれば良く、例えばキシレン、デ
カリン、Ｏ−ジクロロベンゼン、トリクロロベンゼン等
の１種または２種以上を用い得る。The good solvent used in step (a) of the method according to the present invention is capable of dissolving or swelling PE, UHPE and PP (hereinafter, “dissolving” in the present invention means “dissolving or swelling” collectively). Any one of, for example, xylene, decalin, O-dichlorobenzene, trichlorobenzene, or the like may be used.
良溶媒に３成分を溶解させる手法としては、加熱溶解
法を採用できる。この際の最終的な温度は、通常、約10
0〜180℃であり、溶解に要する全所要時間は約10分〜10
時間である。そして、加熱溶解に際し、粘度平均分子量
30万以下のPEおよびPPを先ず溶解せしめ、その後UHPEを
溶解させるようにすると作業時間が短縮できると共に溶
解成分の混合状態がより均一となるので好ましい。な
お、この工程においては得られる溶液中に含まれるPE、
UHPEおよびPPの合計量の濃度が１〜50重量％になるよう
にすると、機械的ストレスに対する抵抗性の特に優れた
セパレータが得られることが判明している。As a method for dissolving the three components in a good solvent, a heat dissolution method can be adopted. The final temperature at this time is usually about 10
0-180 ° C, the total time required for dissolution is about 10 minutes-10
Time. Then, upon heating and melting, the viscosity average molecular weight
It is preferable to dissolve 300,000 or less of PE and PP first, and then dissolve UHPE, since the working time can be shortened and the mixed state of the dissolved components becomes more uniform. In this step, PE contained in the obtained solution,
It has been found that when the concentration of the total amount of UHPE and PP is 1 to 50% by weight, a separator having particularly excellent resistance to mechanical stress can be obtained.
かような（ａ）工程によって得られる溶液は次いで
（ｂ）工程に供される。（ｂ）工程はフィルム成形工程
であり、Ｔダイ法、インフレーション法等の各種製膜技
術を任意に採用できる。The solution obtained by the step (a) is then subjected to the step (b). The step (b) is a film forming step, and various film forming techniques such as a T-die method and an inflation method can be arbitrarily adopted.
上記（ｂ）工程によって得られるフィルム状物は良溶
媒を含有しており、従って、本発明においては（ｃ）工
程において、該フィルム状物を貧溶媒中に浸漬して良溶
媒を除去する。フィルム状物の貧溶媒への浸漬時間は種
々の条件に応じて設定するが、通常、５秒〜30分間であ
る。この工程において用いられる貧溶媒はPE、UHPEおよ
びPPを溶解せず且つ貧溶媒と相溶するものであればよ
く、例えば水や各種有機溶媒を使用できるが、なかでも
アルコール類、特にメタノールが好ましい。The film obtained by the step (b) contains a good solvent. Therefore, in the present invention, in the step (c), the film is immersed in a poor solvent to remove the good solvent. The immersion time of the film in the poor solvent is set according to various conditions, and is usually 5 seconds to 30 minutes. The poor solvent used in this step may be any one that does not dissolve PE, UHPE and PP and is compatible with the poor solvent.For example, water and various organic solvents can be used, and among them, alcohols, particularly methanol are preferable. .
フィルム状物の貧溶媒への浸漬による良溶媒の除去に
より、フィルム状物中の良溶媒存在部が微細な空隙とな
る。そして、この空隙は後に行われる（ｄ）工程の延伸
により微孔へと生長せしめられる。従って、（ｃ）工程
は微孔性フィルムの基本構造形成工程ともいえる。By removing the good solvent by immersing the film in the poor solvent, the good solvent existing portion in the film becomes a fine void. Then, the voids are grown into micropores by stretching in step (d) performed later. Therefore, the step (c) can be said to be a step of forming a basic structure of the microporous film.
なお、（ｂ）工程で得られる良溶媒含有フィルム状物
を（ｃ）工程に供するに際し、フィルム状物が高温であ
る場合には、これを冷却した後（ｃ）工程に供すること
ができる。冷却は自然冷却でもよく、あるいは（ｃ）工
程で用いるような貧溶媒中に浸漬してもよい。後者の方
法により冷却を行う場合は、冷却および良溶媒の除去を
連続した工程として行うこともできる。When the good solvent-containing film obtained in the step (b) is subjected to the step (c), if the film is at a high temperature, it can be cooled and then subjected to the step (c). The cooling may be natural cooling or may be immersed in a poor solvent as used in the step (c). When cooling by the latter method, the cooling and the removal of the good solvent can be performed as a continuous step.
（ｄ）工程においては微細空隙を無数に有するフィル
ム状物が延伸される（延伸は一軸延伸、多軸延伸のいず
れでもよい）。この延伸により、微細空隙が生長拡大せ
しめられ微孔となる。勿論、新たな微孔が形成されるこ
ともある。延伸温度はフィルム状物の融点以下、通常、
約10〜130℃である。また、延伸倍率は、通常、1.2倍以
上、好ましくは1.3〜６倍である。In the step (d), a film-like material having countless fine voids is stretched (stretching may be either uniaxial stretching or multiaxial stretching). By this stretching, the microvoids are expanded and become micropores. Of course, new pores may be formed. Stretching temperature is below the melting point of the film, usually
About 10-130 ° C. The stretching ratio is usually 1.2 times or more, preferably 1.3 to 6 times.
かようにして得られる電池用セパレータは微孔性フィ
ルムであり、その物性値は製造条件によって変わり得る
が、通常、厚さが約５〜300μｍ、微孔の孔径が約0.1〜
20μｍ、気孔率が約20〜90％である。The battery separator thus obtained is a microporous film, and its physical properties may vary depending on the manufacturing conditions, but usually, the thickness is about 5 to 300 μm, and the pore diameter of the micropores is about 0.1 to 0.1 μm.
20 μm, porosity about 20-90%.
なお、この電池用セパレータはPE、UHPEあるいはPPの
うちの少なくとも一つが架橋されていてもよい。また、
一般的特性位を改良するために酸化防止剤、難燃剤、充
填剤等の任意の添加剤を含有していてもよい。The battery separator may have at least one of PE, UHPE and PP crosslinked. Also,
Optional additives such as antioxidants, flame retardants, and fillers may be included to improve general properties.
更に、この電池用セパレータはPE、UHPEおよびPPを必
須成分として含む微孔性フィルム２枚以上を積層したも
のであってもよい。積層タイプのセパレータは、例え
ば、（ｃ）工程による貧溶媒浸漬処理を施したフィルム
状物の２枚以上を重合わせ、PEの融点よりも約10〜40℃
低い温度、線圧約0.01〜10kg/cmの条件で加圧延伸する
ことにより、フィルム状物を微孔化すると共にフィルム
状物相互を一体化する方法により得ることができる。た
だし、この方法による積層タイプのセパレータにおける
積層強度はそれほどではなく、剥離を防止するために
も、製造後の取扱には注意すべきである。Further, the battery separator may be a laminate of two or more microporous films containing PE, UHPE and PP as essential components. The laminated type separator is, for example, two or more film-like materials subjected to the poor solvent immersion treatment in the step (c) are overlapped, and the melting point of PE is about 10 to 40 ° C.
By stretching under pressure at a low temperature and a linear pressure of about 0.01 to 10 kg / cm, the film can be obtained by a method of microporizing the film and integrating the film with each other. However, the lamination strength of the lamination type separator by this method is not so large, and care should be taken in handling after production to prevent peeling.
本発明のセパレータは従来のそれと同様に、正極と負
極の間に介在せしめて電池を組み立てることができる。
この際、正極、負極、電池ケース、電解液等の材質やこ
れら構成要素の配置製造は何ら格別なことを要せず、従
来と同様であってよいものである。The battery of the present invention can be assembled by interposing the separator between the positive electrode and the negative electrode in the same manner as the conventional separator.
At this time, the materials such as the positive electrode, the negative electrode, the battery case, and the electrolytic solution and the arrangement and production of these components do not require any particular matter, and may be the same as the conventional one.
（発明の効果） 本発明は上記のように構成され、PE、UHPEおよびPPを
素材とした微孔性フルムから成るため、比較的低温で電
流遮断機能を発現し、また機械的ストレスに対する抵抗
性に優れ、正負両極の間に配置し渦巻状に巻回する際や
渦巻状体をケースに収納する際に作用する応力によって
も破れ、裂け等の破損を生じ難く、電池の生産効率を向
上させることができる。また、本発明の方法によれば、
電池用セパレータを簡単且つ確実に生産し得る。更に、
このセパレータを組み込んだ電池は安全性に優れてい
る。(Effect of the Invention) Since the present invention is constituted as described above and is made of microporous film made of PE, UHPE and PP, it exhibits a current interrupting function at a relatively low temperature and has a resistance to mechanical stress. It is hardly broken by the stress applied when it is placed between the positive and negative electrodes and wound spirally or when the spiral body is stored in the case, and it is hard to cause breakage such as tearing, and improves the production efficiency of the battery. be able to. According to the method of the present invention,
Battery separators can be easily and reliably produced. Furthermore,
A battery incorporating this separator is excellent in safety.
（実施例） 以下、実施例により本発明を更に詳細に説明する。(Examples) Hereinafter, the present invention will be described in more detail with reference to examples.
実施例１ ガラス容器にキシレン1000重量部、デカリン1000重量
部、粘度平均分子量20万、密度0.95、メルトインデック
ス20g/minのPE粉末20重量部および粘度平均分子量30万
のPP粉末50重量部を秤量して入れ、攪拌機で攪拌しなが
ら液温を25℃から140℃まで昇温させ、同温度に１時間
保持してPEおよびPP溶解させる。Example 1 In a glass container, 1000 parts by weight of xylene, 1000 parts by weight of decalin, 20 parts by weight of a PE powder having a viscosity average molecular weight of 200,000, a density of 0.95, and a melt index of 20 g / min, and 50 parts by weight of a PP powder having a viscosity average molecular weight of 300,000 were weighed. Then, while stirring with a stirrer, raise the liquid temperature from 25 ° C. to 140 ° C., and maintain the same temperature for 1 hour to dissolve PE and PP.
次に、この溶液（液温140℃に維持）中に粘度平均分
子量300万のUHPE粉末150重量部を加え攪拌を１時間続け
てUHPEを溶解させる。Next, 150 parts by weight of UHPE powder having a viscosity-average molecular weight of 3,000,000 is added to this solution (maintained at a liquid temperature of 140 ° C.), and stirring is continued for 1 hour to dissolve UHPE.
この溶液をＴダイ押出機を用いて厚さ75μｍのフィル
ム状に押出し、メタノール中に１分間浸漬して冷却しロ
ール状芯体に巻き取る。なお、押出温度は150℃とし、
吐出量は100g/minとした。This solution is extruded into a film having a thickness of 75 μm using a T-die extruder, immersed in methanol for 1 minute, cooled, and wound around a roll-shaped core. The extrusion temperature was 150 ° C,
The discharge rate was 100 g / min.
次いで、このフィルム状物をメタノール中に10分間浸
漬し、フィルム状物中に含有されているキシレンおよび
デカリンを抽出除去して引上げ、風乾する。Next, the film is immersed in methanol for 10 minutes, xylene and decalin contained in the film are extracted and removed, and the film is air-dried.
その後、温度120℃、速度0.8m/minの条件で延伸倍率
２倍に一軸延伸することにより、厚さ25μｍ、気孔率64
％の微孔性電池用セパレータ（試料１）を得た。Thereafter, the film was monoaxially stretched at a stretching ratio of 2 at a temperature of 120 ° C. and a speed of 0.8 m / min to obtain a thickness of 25 μm and a porosity of 64.
% Of a microporous battery separator (sample 1).
なお、気孔率はフィルム状物の寸法が縦、横共に35mm
になるように切断し、その厚さ（Ｄ）および重量（Ｅ）
を測定し、式（Ｉ）により見掛密度（Ｇ）を算出し、更
に、UHPEの真比重（Ｆ）を用いて式（II）により、算出
した。The porosity of the film is 35 mm in both vertical and horizontal dimensions.
And its thickness (D) and weight (E)
Was measured, the apparent density (G) was calculated by the formula (I), and further calculated by the formula (II) using the true specific gravity (F) of UHPE.
なお、式（Ｉ）中における（Ｄ）および（Ｅ）の単位
は「μｍ」および「ｇ」である。 The units of (D) and (E) in the formula (I) are “μm” and “g”.
実施例２ Ｔダイ押出機による押出し厚さを50μｍとすること以
外は実施例１と同様にして、PE、UHPEおよびPPの溶媒へ
の溶解、フィルム成形、溶媒の抽出除去および風乾を行
う。Example 2 Dissolving PE, UHPE and PP in a solvent, forming a film, extracting and removing a solvent, and air-drying are performed in the same manner as in Example 1 except that the extrusion thickness by a T-die extruder is set to 50 μm.
次に、フィルム状物を２枚重合わせ、温度120℃、速
度0.8m/min、線圧1.3kg/cmの条件で延伸倍率２倍に一軸
延伸することにより、厚さ25μｍ、気孔率60％の微孔性
で且つ積層タイプの電池用セパレータ（試料２）を得
た。Next, two film-like materials are superimposed, uniaxially stretched at a stretching ratio of 2 at a temperature of 120 ° C., a speed of 0.8 m / min, and a linear pressure of 1.3 kg / cm to obtain a thickness of 25 μm and a porosity of 60%. A microporous and laminated type battery separator (Sample 2) was obtained.
実施例３ PE、UHPEおよびPPの配合割合（重量部）を第１表に示
すようにすること以外は実施例１と同様に作業して、３
種の微孔性電池用セパレータ（試料３〜５）を得た。な
お、これらセパレータの厚さはいずれも25μｍであり、
気孔率は試料３が62％、試料４が66％、試料５が65％で
あった。Example 3 The same operation as in Example 1 was carried out except that the mixing ratios (parts by weight) of PE, UHPE and PP were as shown in Table 1, and 3
Various kinds of microporous battery separators (samples 3 to 5) were obtained. The thickness of each of these separators is 25 μm,
The porosity was 62% for sample 3, 66% for sample 4, and 65% for sample 5.
比較例１ PPを使用しないこと以外は実施例１と同様に作業し
て、厚さ25μｍ、気孔率60％の微孔性電池用セパレータ
（試料６）を得た。 Comparative Example 1 A microporous battery separator (sample 6) having a thickness of 25 μm and a porosity of 60% was obtained in the same manner as in Example 1 except that PP was not used.
比較例２ 厚さ25μｍ、気孔率49％のPP製微孔フィルムを電池用
セパレータ（試料７）とした。Comparative Example 2 A microporous film made of PP having a thickness of 25 μm and a porosity of 49% was used as a battery separator (sample 7).
これら実施例および比較例で得られたセパレータの性
能を知るため、リチウムを負極、二酸化マンガンを主成
分とする活物質を正極とし、電解液としてプロピレンカ
ーボネートとジメトキシエタンを同重量混合した液（こ
れに電解質としてのLiClO4を濃度が1mol/になるよう
に溶解してある）を用いると共に渦巻式電極を採用して
非水電解液電池を作製し、下記要領で試験を行った。得
られた結果を第２表に示す。In order to know the performance of the separators obtained in these Examples and Comparative Examples, lithium was used as a negative electrode, manganese dioxide as an active material was used as a positive electrode, and propylene carbonate and dimethoxyethane were mixed as an electrolyte by the same weight (this Was prepared by dissolving LiClO 4 as an electrolyte so as to have a concentration of 1 mol /) and a spiral electrode was used to fabricate a nonaqueous electrolyte battery, which was tested in the following manner. Table 2 shows the obtained results.
電池缶壁に、熱電対を取り付けて記録し、その最高温
度を求めた。A thermocouple was attached to the battery can wall and recorded, and the maximum temperature was determined.
〔電池容量〕 温度25℃、抵抗25Ωの条件で放電を行い、電池容量を
求めた。なお、この際には電圧が2.5Vになった時を終点
とした。[Battery capacity] Discharge was performed under the conditions of a temperature of 25 ° C and a resistance of 25Ω, and the battery capacity was determined. In this case, the end point was when the voltage became 2.5 V.
250Vの電圧を電池の両電極間に印加し、抵抗が10MΩ
以下のものを不良とした。A voltage of 250 V is applied between both electrodes of the battery, and the resistance is 10 MΩ
The following were regarded as defective.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｂ２９Ｌ 7:00 (56)参考文献 特開 平２−21559（ＪＰ，Ａ) 特開 昭57−49629（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) H01M 2/16 C08J 9/28 ＪＯＩＳ──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. 6 Identification symbol FIB29L 7:00 (56) References JP-A-2-21559 (JP, A) JP-A-57-49629 (JP, A) ( 58) Field surveyed (Int.Cl. 6 , DB name) H01M 2/16 C08J 9/28 JOIS
Claims (3)
粘度平均分子量100万以上のポリエチレン、およびポリ
プロピレンを含む混合物から成る微孔性電池用セパレー
タ。1. A polyethylene having a viscosity average molecular weight of 300,000 or less,
A microporous battery separator made of a mixture containing polyethylene having a viscosity average molecular weight of 1,000,000 or more and polypropylene.
均分子量100万以上のポリエチレン、およびポリプロピ
レンを良溶媒に溶解する工程、 （ｂ）上記工程で得た溶液を用いてフィルム成形する工
程、 （ｃ）上記工程で得たフィルム状物を貧溶媒に浸漬する
工程、 （ｄ）上記浸漬処理後のフィルム状物を延伸する工程、 を含む微孔性電池用セパレータの製造法。2. The following four steps: (a) a step of dissolving a polyethylene having a viscosity average molecular weight of 300,000 or less, a polyethylene having a viscosity average molecular weight of 1,000,000 or more, and polypropylene in a good solvent; A microporous battery comprising: a step of forming a film using a solution; (c) a step of immersing the film obtained in the above step in a poor solvent; and (d) a step of stretching the film after the immersion treatment. For manufacturing separators for garments.
められたセパレータを有し、このセパレータが粘度平均
分子量30万以下のポリエチレン、粘度平均分子量100万
以上のポリエチレン、およびポリプロピレンを含む混合
物から成る微孔性フィルムであることを特徴とする電
池。3. A positive electrode, a negative electrode and a separator interposed between these two electrodes, wherein the separator comprises a mixture containing polyethylene having a viscosity average molecular weight of 300,000 or less, polyethylene having a viscosity average molecular weight of 1,000,000 or more, and polypropylene. A battery comprising a microporous film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2249334A JP2952017B2 (en) | 1990-09-18 | 1990-09-18 | Battery separator, method for producing the same, and battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2249334A JP2952017B2 (en) | 1990-09-18 | 1990-09-18 | Battery separator, method for producing the same, and battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04126352A JPH04126352A (en) | 1992-04-27 |
| JP2952017B2 true JP2952017B2 (en) | 1999-09-20 |
Family
ID=17191472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2249334A Expired - Lifetime JP2952017B2 (en) | 1990-09-18 | 1990-09-18 | Battery separator, method for producing the same, and battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2952017B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9455429B2 (en) | 2008-03-05 | 2016-09-27 | Sony Corporation | Non-aqueous electrolyte secondary battery |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993001623A1 (en) * | 1991-07-05 | 1993-01-21 | Asahi Kasei Kogyo Kabushiki Kaisha | Separator of battery wherein organic electrolyte is used and production thereof |
| JP3342755B2 (en) * | 1992-10-28 | 2002-11-11 | 旭化成株式会社 | Separator for cylindrical electric parts |
| US5948557A (en) * | 1996-10-18 | 1999-09-07 | Ppg Industries, Inc. | Very thin microporous material |
| JP4943599B2 (en) * | 2001-08-09 | 2012-05-30 | セイコーエプソン株式会社 | Resin filter for inkjet recording equipment |
| KR100599898B1 (en) | 2002-08-28 | 2006-07-19 | 아사히 가세이 케미칼즈 가부시키가이샤 | Polyolefin Microporous Membrane and Method of Evaluating The Same |
| US8338017B2 (en) | 2007-10-12 | 2012-12-25 | Toray Battery Separator Film Co., Ltd. | Microporous membrane and manufacturing method |
| KR20110084541A (en) | 2008-11-19 | 2011-07-25 | 미쓰이 가가쿠 가부시키가이샤 | Polyolefin resin composition and applications thereof |
| JP5462227B2 (en) | 2011-09-07 | 2014-04-02 | 株式会社日本製鋼所 | Process for producing polyolefin microporous stretched film with cellulose nanofiber, polyolefin microporous stretched film with cellulose nanofiber, and separator for non-aqueous secondary battery |
| CN110690389B (en) * | 2019-09-20 | 2022-04-15 | 上海恩捷新材料科技有限公司 | Reinforced lithium battery diaphragm and manufacturing method thereof |
-
1990
- 1990-09-18 JP JP2249334A patent/JP2952017B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9455429B2 (en) | 2008-03-05 | 2016-09-27 | Sony Corporation | Non-aqueous electrolyte secondary battery |
| US9859590B2 (en) | 2008-03-05 | 2018-01-02 | Sony Corporation | Battery |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04126352A (en) | 1992-04-27 |
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