JP3948762B2 - Zinc bromine secondary battery separator - Google Patents
Zinc bromine secondary battery separator Download PDFInfo
- Publication number
- JP3948762B2 JP3948762B2 JP03325996A JP3325996A JP3948762B2 JP 3948762 B2 JP3948762 B2 JP 3948762B2 JP 03325996 A JP03325996 A JP 03325996A JP 3325996 A JP3325996 A JP 3325996A JP 3948762 B2 JP3948762 B2 JP 3948762B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- molecular weight
- polyethylene
- separator
- 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
- Cell Separators (AREA)
- Hybrid Cells (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、電力貯蔵システム、電気自動車用などの用途として開発が進められている亜鉛臭素２次電池で使用するセパレーターにおいて、優れた機械的特性をもち、厚さの薄い、耐熱性、耐ストレスクラック性にすぐれ、かつ優れた耐薬品性、優れた透過性能を備え、かつ微細な孔からなる均質な三次元の多孔構造を有する、亜鉛臭素２次電池用セパレーターに関する。
【０００２】
【従来の技術】
亜鉛臭素２次電池用セパレーターには、クーロン効率のよいイオン交換膜、耐薬品性に優れる四フッ化エチレン多孔膜、ポリオレフィン多孔膜が用いられているが、これらの中で安価で耐薬品性にすぐれるものとして特公平５―２７２３３号公報に見られる様なポリエチレンと微粉シリカからなるセパレーターがある。しかし、特公平５―２７２３３号公報に記載されているセパレーターは、特開昭６２―１７９４５号公報に記載されているように亜鉛臭素２次電池を作る際、セパレーターに電極枠を射出成形により取り付ける工程がある。この時、加熱によりセパレーターにひび割れが発生するという耐熱性に問題があった。またこのセパレーターは亜鉛臭素２次電池で長期間使用すると、膜にひび割れが発生してしまうという耐ストレスクラック性に問題点があった。
【０００３】
【発明が解決しようとする課題】
本発明の課題は、上記のような問題点を解決し、優れた耐薬品性、優れた透過性能を備え、かつ、微細な孔からなる均質な三次元の多孔構造を有し、耐熱性、耐ストレスクラック性にすぐれた亜鉛臭素２電池次用セパレーターを提供することである。
【０００４】
【課題を解決するための手段】
本発明者らは、これらの課題を解決するために鋭意研究した結果、粘度平均分子量５０００００以上の超高分子量ポリエチレンを５重量％以上含み且つ全体の粘度平均分子量が３５００００以上のポリエチレンと、微粉シリカを使用する事により、耐熱性、耐ストレスクラック性にも優れた、亜鉛臭素２次電池用セパレーターが得られることを見出した。
【０００５】
より具体的に述べれば、粘度平均分子量５０００００以上の超高分子量ポリエチレンを５重量％以上含み且つ全体の粘度平均分子量が３５００００以上のポリエチレンと、微粉シリカ、有機液状体を均一加熱混練後、押出成形しシート状の膜をつくり有機液状体を抽出することにより、気孔率が３０〜７０％、最大孔径が０．０５μｍ〜１μｍ、厚さが０.１〜２ｍｍである亜鉛臭素２次電池用セパレーターが得られ、このセパレーターは、縦方向の引っ張り破断強さが３０ｋｇ／ｃｍ2 以上で、縦方向の引っ張り破断強さを横方向の引っ張り破断強さで除した値が０．４以上、３以下であり、機械的特性に優れ、耐熱性、耐ストレスクラック性に優れたものである。
【０００６】
即ち、本発明は、以下の通りである。
１．粘度平均分子量５０００００以上の超高分子量ポリエチレンを５重量％以上含み且つ全体の粘度平均分子量が３５００００以上のポリエチレンと微粉シリカからなり、該ポリエチレンの重量を微粉シリカの重量で除した比が０．５〜４であって、縦方向の引っ張り破断強さが３０ｋｇ／ｃｍ ２ 以上で、縦方向の引っ張り破断強さを横方向の引っ張り破断強さで除した値が０．４以上、３以下であることを特徴とする亜鉛臭素２次電池用セパレーター。
２．最大孔径が０．０５μｍ〜１μｍであることを特徴とする上記１．に記載の亜鉛臭素２次電池用セパレーター。
３．微粉シリカが親水性シリカである上記１．又は２．に記載の亜鉛臭素２次電池用セパレーター。
【０００７】
本発明に用いられるポリエチレンは、粘度平均分子量５０００００以上の超高分子量ポリエチレンを５重量％以上含み、且つ全体の粘度平均分子量が３５００００以上のポリエチレンからなるものである。ポリエチレンとしては、二種類以上のポリエチレンを組み合わせて用いることが出来るが、全体としての粘度平均分子量が３５００００以上であることが必要である。超高分子量ポリエチレンの割合が５重量％未満では、全体の粘度平均分子量が３５００００以上であっても好ましくない。また、粘度平均分子量３５００００未満では、耐熱性が悪くひび割れが発生する。また機械的特性が弱いため耐ストレスクラック性が悪く、亜鉛臭素２次電池用セパレーターとして使用中にひび割れが発生する。粘度平均分子量３５００００以上であっても縦方向の引っ張り破断強さが３０ｋｇ／ｃｍ2 未満では、機械的特性が弱いため耐ストレスクラック性が悪く、亜鉛臭素２次電池用セパレーターとして使用中にひび割れが発生する。好ましくは４０ｋｇ／ｃｍ2 以上である。
【０００８】
縦方向の引っ張り破断強さを横方向の引っ張り破断強さで除した値が０．４未満の場合、あるいは３を越えると、亜鉛臭素２次電池用セパレーターとして使用時の収縮が大きくひび割れが発生してしまう。好ましくは０．５以上、２．５以下である。膜の厚さは０.１〜２ｍｍが好ましい。０.１ｍｍ未満の膜は薄いためひび割れが発生し易くなり、２ｍｍを越えると厚いため抵抗が大きくなり、亜鉛臭素２次電池用セパレーターとして不十分となる傾向がある。
【０００９】
微粉シリカとしては、親水性の湿式シリカ、乾式シリカやこれらの微粉シリカを表面処理をした親油性シリカなどが挙げられる。親水性の微粉シリカを使用した方が、電解液との濡れが良く、亜鉛臭素２次電池用セパレーターとして好ましい。
本発明のセパレーターの製造方法を詳しく説明すると、粘度平均分子量５０００００以上の超高分子量ポリエチレンを５重量％以上含み且つ全体の粘度平均分子量３５００００以上のポリエチレン、微粉シリカ、有機液状体の合計重量に対して、ポリエチレンの重量を微粉シリカの重量で除した比が０．５〜４になるように、ポリエチレン８〜６０重量％、好ましくは１０〜５０重量％、微粉シリカ８〜５０重量％、好ましくは、１０〜３５重量％、有機液状体３０〜７５重量％、好ましくは４０〜６５重量％の３成分を混合する。
【００１０】
この時、ポリエチレンの重量を微粉シリカの重量で除した比が０．５未満では、ポリエチレンの割合が少ないため機械的特性が弱い膜となり、また、ポリエチレンの重量を微粉シリカの重量で除した比が４を越えると、微粉シリカが少ないため亜鉛臭素２次電池用セパレーターとして用いた時の電解液の濡れ性が不十分となる傾向がある。また、ポリエチレンが８重量％未満では、ポリエチレンが少ないため機械的特性が弱く、成形性も低下し、また、６０重量％を越えると、気孔率が低く透過性能が不十分となる傾向がある。微粉シリカの量が８重量％未満では、微粉シリカが少なく電気抵抗の高い膜となり、また、５０重量％を越えると、押出成形時の流動性が低下し、かつ、得られる成形品は脆くなる傾向がある。
【００１１】
有機液状体としては、例えば、フタル酸ジエチル、フタル酸ジブチル、フタル酸ジオクチルなどのフタル酸エステル、セバシン酸ジオクチルなどのセバシン酸エステル、アジピン酸ジオクチルなどのアジピン酸エステル、トリメリット酸トリオクチルなどのトリメリット酸エステル、リン酸トリブチル、リン酸オクチルジフェニールなどのリン酸エステル、流動パラフィン等やこれらの有機液状体の混合物が挙げられる。有機液状体の量は、３０重量％未満では、気孔形成に対する寄与率が低下し、高い気孔率、高い透過性能を持つセパレーター（微多孔膜）が得られない。また、７５重量％を越えると、成形が難しく、機械的特性も弱い物となる。
【００１２】
本発明における構成は主に、粘度平均分子量５０００００以上の超高分子量ポリエチレンを５重量％以上含み且つ全体の粘度平均分子量３５００００以上のポリエチレン、微粉シリカ、有機液状体の３成分より構成される。しかし、他に本発明の効果を大きく阻害しない範囲で、滑剤、酸化防止剤、紫外線吸収剤、可塑剤、成形助剤などを必要に応じて添加することは何ら差し支えない。
【００１３】
これら３成分の混合には、スーパーミキサー、リボンブレンダー、Ｖ−ブレンダーなどの混合機を用いた通常の方法で充分である。
この混合物は、押出機、バンバリーミキサー、二本ロール、ニーダーなどの溶融混練機により混練される。本発明に用いられる溶融成形方法としては、Ｔダイ法を用いた押出成形、また混合物を直接押出機、ニーダールーダーなどの混練・押出機能を有する装置で成形することも可能である。
【００１４】
次いで、これらの方法により得られた膜中の有機液状体を溶剤によって抽出を行う。抽出に用いる溶剤としては、有機液状体を溶解し得るものであり、ポリエチレンを実質的に溶解するものであってはならない。抽出は、回分法、向流多段法などの膜状物の一般的な抽出法により容易に行われる。抽出に用いられる溶剤としては、メタノール、アセトン、メチルエチルケトンなどが挙げられるが、特に塩化メチレン等のハロゲン系炭化水素が好ましい。
【００１５】
有機液状体が抽出されることにより、本発明の亜鉛臭素２次電池用セパレーターが得られる。なお、本発明のセパレーター（微多孔膜）中には、有機液状体が膜の性能を損なわない範囲で残存することが許され、その残存量は３重量％以下、好ましくは２重量％以下である。
【００１６】
【発明の実施の形態】
以下、実施例、比較例により本発明を更に詳しく説明するが、本発明はこれらの実施例に限定されるものではない。
なお，実施例における試験方法は次の通りである。
１）膜厚さ：マイクロメータにて読み取る。
２）最大孔径：ＡＳＴＭ Ｆ３１６−８６に準拠。エタノール中でのバブルポイントより算出。
３）気孔率：下記の式より算出。
気孔率＝｛１−〔０．１×Ｘ／（Ｙ×Ｚ）〕｝×１００
Ｘ：膜の重さ（ｇ／ｄｍ2 ）
Ｙ：膜の比重（ポリエチレンの比重０.９５、微粉シリカの比重１.９）を用いて組成比から計算。
Ｚ：膜の厚さ（ｍｍ）
４）機械的特性：引っ張り破断強さ（ＪＩＳＫ７１１３による）
５）超高分子量ポリエチレン、ポリエチレンの粘度平均分子量（ＭV ）：溶剤（デカリン）を用い、測定温度１３５℃で極限粘度（η）を測定し、下記の式より算出。
（η）＝６．２×１０-4ＭV 0.7 （Ｃｈｉａｎｇの式）
６）耐熱性：セパレーターに射出成形により枠を取り付けた際、膜にひび割れをおこしたセパレーター枚数の割合。
７）耐ストレスクラック性：亜鉛臭素２次電池セパレーターとして使用して取り出した後、膜にひび割れが発生していたセパレーター枚数の割合。
【００１７】
【実施例１】
微粉シリカ２０重量％とジオクチルフタレート５０重量％をスーパーミキサーで混合し、これに粘度平均分子量３００００００の超高分子量ポリエチレン２重量％、粘度平均分子量３０００００の高分子量ポリエチレン２８重量％を添加、再度スーパーミキサーで混合した。該混合物を３０ｍ／ｍ二軸押出機に４５０ｍｍ幅のＴダイを取り付けたフィルム製造機で膜厚さ１．０ｍｍの膜状に成形した。成形された膜は，塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表１に示す。
【００１８】
【実施例２】
微粉シリカ２３重量％とジオクチルフタレート５４重量％をスーパーミキサーで混合し、これに粘度平均分子量３００００００の超高分子量ポリエチレン９重量％、粘度平均分子量３０００００の高分子量ポリエチレン１４重量％を用いた以外は、実施例１と同様に行い厚さ０．６ｍｍの膜状に成形した。成形された膜を、塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表１に示す。
【００１９】
【実施例３】
微粉シリカ２３重量％とジオクチルフタレート５４重量％をスーパーミキサーで混合し、これに粘度平均分子量３００００００の超高分子量ポリエチレン９重量％、粘度平均分子量１０００００のポリエチレン１４重量％を用いた以外は、実施例１と同様に行い厚さ１．２ｍｍの膜状に成形した。成形された膜を、塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表１に示す。
【００２０】
【実施例４】
微粉シリカ２３重量％とジオクチルフタレート５４重量％をスーパーミキサーで混合し、これに粘度平均分子量６０００００の超高分子量ポリエチレン９重量％、粘度平均分子量３０００００のポリエチレン１４重量％を用いた以外は、実施例１と同様に行い厚さ１．５ｍｍの膜状に成形した。成形された膜を、塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表１に示す。
【００２１】
【比較例１】
微粉シリカ２３重量％とジオクチルフタレート５４重量％をスーパーミキサーで混合し、これにポリエチレンとして、粘度平均分子量４０００００のポリエチレン２３重量％のみを用いた以外は、実施例１と同様に行い厚さ１．０ｍｍの膜状に成形した。成形された膜を、塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表２に示す。
【００２２】
【比較例２】
微粉シリカ２３重量％とジオクチルフタレート５４重量％をスーパーミキサーで混合し、これに粘度平均分子量３００００００の超高分子量ポリエチレン９重量％、粘度平均分子量５００００のポリエチレン１４重量％を用いた以外は、実施例１と同様に行い厚さ１．２ｍｍの膜状に成形した。成形された膜を、塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表２に示す。
【００２３】
【比較例３】
微粉シリカ２３重量％とジオクチルフタレート５４重量％をスーパーミキサーで混合し、これに粘度平均分子量３００００００の超高分子量ポリエチレン１重量％、粘度平均分子量３０００００のポリエチレン２２重量％を用いた以外は、実施例１と同様に行い厚さ１．２ｍｍの膜状に成形した。成形された膜を、塩化メチレン中で２０分間浸漬しジオクチルフタレートを抽出した後乾燥した。得られた膜の特性を表２に示す。
【００２４】
【表１】
【表２】
【発明の効果】
本発明により、耐熱性、耐ストレスクラック性にすぐれ、かつ優れた耐薬品性、優れた透過性能を備え、かつ微細な孔からなる均質な三次元の多孔構造を有する亜鉛臭素２次電池用セパレーターが得られる。[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is a separator for use in a zinc bromine secondary battery that is being developed for applications such as power storage systems and electric vehicles, and has excellent mechanical properties, thin thickness, heat resistance, and stress resistance. The present invention relates to a zinc bromine secondary battery separator having excellent crack resistance, excellent chemical resistance, excellent permeation performance, and a homogeneous three-dimensional porous structure composed of fine pores.
[0002]
[Prior art]
Zinc bromine secondary battery separators use Coulomb-efficient ion exchange membranes, polytetrafluoroethylene porous membranes and polyolefin porous membranes with excellent chemical resistance. Among these, inexpensive and chemical resistant An excellent separator is a separator made of polyethylene and finely divided silica as disclosed in JP-B-5-27233. However, the separator described in Japanese Patent Publication No. 5-27233 is attached to an electrode frame by injection molding when making a zinc bromine secondary battery as described in Japanese Patent Laid-Open No. 62-17945. There is a process. At this time, there was a problem in heat resistance that cracking occurred in the separator by heating. In addition, this separator has a problem in resistance to stress cracking that a film is cracked when used for a long time in a zinc bromine secondary battery.
[0003]
[Problems to be solved by the invention]
The problem of the present invention is to solve the above problems, have excellent chemical resistance, excellent permeation performance, and have a homogeneous three-dimensional porous structure consisting of fine pores, heat resistance, Another object is to provide a secondary separator for zinc bromine 2 batteries having excellent stress crack resistance.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve these problems, the present inventors have found that a polyethylene containing 5% by weight or more of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 500,000 or more and a total viscosity average molecular weight of 350,000 or more, and fine silica It has been found that a separator for a zinc bromine secondary battery excellent in heat resistance and stress crack resistance can be obtained by using.
[0005]
More specifically, a polyethylene containing 5% by weight or more of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 500,000 or more and an overall viscosity average molecular weight of 350,000 or more, finely divided silica and an organic liquid are uniformly heated and kneaded, followed by extrusion molding. A separator for a zinc bromine secondary battery having a porosity of 30 to 70%, a maximum pore diameter of 0.05 μm to 1 μm, and a thickness of 0.1 to 2 mm by forming a sheet-like film and extracting an organic liquid This separator has a longitudinal tensile breaking strength of 30 kg / cm 2 or more, and a value obtained by dividing the longitudinal tensile breaking strength by the lateral tensile breaking strength is 0.4 or more and 3 or less. It has excellent mechanical properties, heat resistance and stress crack resistance.
[0006]
That is, the present invention is as follows.
1. A ratio of 5% by weight or more of ultra high molecular weight polyethylene having a viscosity average molecular weight of 500,000 or more and a total viscosity average molecular weight of 350,000 or more and fine silica, and the ratio of the weight of the polyethylene divided by the weight of fine silica is 0.5. The tensile breaking strength in the longitudinal direction is 30 kg / cm 2 or more, and the value obtained by dividing the longitudinal tensile breaking strength by the tensile breaking strength in the lateral direction is 0.4 or more and 3 or less. The separator for zinc bromine secondary batteries characterized by the above-mentioned.
2. The above-mentioned 1. characterized in that the maximum pore diameter is 0.05 μm to 1 μm. The separator for zinc bromine secondary batteries described in 1.
3. 1. The fine silica described above is hydrophilic silica. Or 2. The separator for zinc bromine secondary batteries described in 1.
[0007]
The polyethylene used in the present invention is made of polyethylene containing 5% by weight or more of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 500,000 or more and having a total viscosity average molecular weight of 350,000 or more. As polyethylene, two or more types of polyethylene can be used in combination, but the viscosity average molecular weight as a whole is required to be 350,000 or more. If the ratio of ultra high molecular weight polyethylene is less than 5% by weight, it is not preferable even if the total viscosity average molecular weight is 350,000 or more. On the other hand, if the viscosity average molecular weight is less than 350,000, the heat resistance is poor and cracking occurs. Moreover, since the mechanical properties are weak, the stress crack resistance is poor, and cracking occurs during use as a separator for a zinc bromine secondary battery. Even when the viscosity average molecular weight is 350,000 or more, if the tensile strength at break in the longitudinal direction is less than 30 kg / cm 2 , the mechanical properties are weak, so the stress crack resistance is poor, and cracks occur during use as a separator for a zinc bromine secondary battery. appear. Preferably it is 40 kg / cm 2 or more.
[0008]
When the value obtained by dividing the tensile strength in the longitudinal direction by the tensile strength in the transverse direction is less than 0.4, or exceeding 3, the shrinkage during use as a separator for a zinc bromine secondary battery is greatly cracked. Resulting in. Preferably they are 0.5 or more and 2.5 or less. The thickness of the film is preferably 0.1 to 2 mm. Since the film of less than 0.1 mm is thin, cracks are likely to occur, and when it exceeds 2 mm, the film is thick and the resistance increases, which tends to be insufficient as a separator for a zinc bromine secondary battery.
[0009]
Examples of the fine powder silica include hydrophilic wet silica, dry silica, and lipophilic silica obtained by surface treatment of these fine powder silica. The use of hydrophilic finely divided silica is preferable as a separator for a zinc bromine secondary battery because the wettability with the electrolytic solution is good.
Describing the manufacturing method of the separator of the present invention in detail, the viscosity-average molecular weight 500,000 or more ultra-high molecular weight polyethylene containing 5 wt% or more and the total viscosity average molecular weight 350,000 or more polyethylene, finely divided silica, the total weight of the organic liquid On the other hand, polyethylene is 8 to 60% by weight, preferably 10 to 50% by weight, and finely divided silica is 8 to 50% by weight, preferably so that the ratio obtained by dividing the weight of polyethylene by the weight of fine silica is 0.5 to 4. Is a mixture of three components of 10 to 35% by weight and organic liquid 30 to 75% by weight, preferably 40 to 65% by weight.
[0010]
At this time, if the ratio of the weight of polyethylene divided by the weight of fine silica is less than 0.5, the ratio of the weight of polyethylene divided by the weight of fine powder silica becomes a film with weak mechanical properties because of the small proportion of polyethylene. When the value exceeds 4, since the amount of fine silica is small, the wettability of the electrolytic solution when used as a separator for a zinc bromine secondary battery tends to be insufficient. On the other hand, if the polyethylene content is less than 8% by weight, the mechanical properties are weak and the moldability is deteriorated because the polyethylene content is small. If the polyethylene content exceeds 60% by weight, the porosity tends to be low and the permeation performance tends to be insufficient. When the amount of finely divided silica is less than 8% by weight, a finely divided silica results in a film having a high electric resistance. When the finely divided silica exceeds 50% by weight, the fluidity at the time of extrusion molding is lowered and the resulting molded product becomes brittle. Tend.
[0011]
Examples of organic liquids include phthalate esters such as diethyl phthalate, dibutyl phthalate and dioctyl phthalate, sebacic acid esters such as dioctyl sebacate, adipic acid esters such as dioctyl adipate, and trioctyl trimellitic acid. Examples thereof include phosphate esters such as merit acid ester, tributyl phosphate and octyl diphenyl phosphate, liquid paraffin, and mixtures of these organic liquids. If the amount of the organic liquid is less than 30% by weight, the contribution to pore formation is reduced, and a separator (microporous membrane) having high porosity and high permeability cannot be obtained. On the other hand, if it exceeds 75% by weight, molding is difficult and mechanical properties are weak.
[0012]
Configuration in the present invention is mainly composed of three components of a viscosity-average molecular weight 500,000 or more ultra-high molecular weight polyethylene 5 wt% or more unrealized and overall viscosity average molecular weight 350,000 or more polyethylene, finely divided silica, organic liquid . However, a lubricant, an antioxidant, an ultraviolet absorber, a plasticizer, a molding aid and the like may be added as necessary as long as the effects of the present invention are not significantly impaired.
[0013]
For mixing these three components, a normal method using a mixer such as a super mixer, a ribbon blender, or a V-blender is sufficient.
This mixture is kneaded by a melt kneader such as an extruder, a Banbury mixer, a two-roller, or a kneader. As the melt molding method used in the present invention, it is also possible to perform extrusion molding using a T-die method, or to form the mixture directly using an apparatus having a kneading / extrusion function such as an extruder or a kneader ruder.
[0014]
Next, the organic liquid in the film obtained by these methods is extracted with a solvent. The solvent used for the extraction is capable of dissolving the organic liquid and should not substantially dissolve polyethylene. Extraction is easily performed by a general extraction method of a film-like material such as a batch method or a countercurrent multistage method. Examples of the solvent used for extraction include methanol, acetone, methyl ethyl ketone, and the like, and halogenated hydrocarbons such as methylene chloride are particularly preferable.
[0015]
By extracting the organic liquid, the zinc bromine secondary battery separator of the present invention is obtained. In the separator (microporous membrane) of the present invention, the organic liquid is allowed to remain within a range not impairing the performance of the membrane, and the residual amount is 3% by weight or less, preferably 2% by weight or less. is there.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.
In addition, the test method in an Example is as follows.
1) Film thickness: Read with a micrometer.
2) Maximum pore diameter: Conforms to ASTM F316-86. Calculated from bubble points in ethanol.
3) Porosity: calculated from the following formula.
Porosity = {1- [0.1 × X / (Y × Z)]} × 100
X: film weight (g / dm 2 )
Y: Calculated from the composition ratio using the specific gravity of the film (specific gravity of polyethylene 0.95, specific gravity of fine silica 1.9).
Z: film thickness (mm)
4) Mechanical properties: Tensile strength at break (according to JISK7113)
5) Ultra high molecular weight polyethylene, Viscosity average molecular weight (M V ) of polyethylene: Using a solvent (decalin), the intrinsic viscosity (η) is measured at a measurement temperature of 135 ° C., and calculated from the following formula.
(Η) = 6.2 × 10 −4 M V 0.7 (Chiang's formula)
6) Heat resistance: The ratio of the number of separators that cracked the membrane when a frame was attached to the separator by injection molding.
7) Stress crack resistance: The ratio of the number of separators in which the film had cracks after being taken out as a zinc bromine secondary battery separator.
[0017]
[Example 1]
20% by weight of fine silica and 50% by weight of dioctyl phthalate are mixed in a super mixer, and 2% by weight of ultra high molecular weight polyethylene having a viscosity average molecular weight of 3000000 and 28% by weight of high molecular weight polyethylene having a viscosity average molecular weight of 300,000 are added thereto. Mixed. The mixture was formed into a film having a thickness of 1.0 mm by a film manufacturing machine in which a 450 mm wide T-die was attached to a 30 m / m twin screw extruder. The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. Table 1 shows the characteristics of the obtained film.
[0018]
[Example 2]
Except that 23% by weight of fine silica and 54% by weight of dioctyl phthalate were mixed with a super mixer, and 9% by weight of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 3000000 and 14% by weight of high molecular weight polyethylene having a viscosity average molecular weight of 300000 were used. It carried out similarly to Example 1 and shape | molded in the film form of thickness 0.6mm . The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. Table 1 shows the characteristics of the obtained film.
[0019]
[Example 3]
Example: Except that 23% by weight of fine silica and 54% by weight of dioctyl phthalate were mixed by a super mixer, and 9% by weight of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 3000000 and 14% by weight of polyethylene having a viscosity average molecular weight of 100,000 were used. 1 was performed to form a film having a thickness of 1.2 mm. The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. Table 1 shows the characteristics of the obtained film.
[0020]
[Example 4]
Example: Except that 23% by weight of fine silica and 54% by weight of dioctyl phthalate were mixed with a super mixer, and 9% by weight of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 600,000 and 14% by weight of polyethylene having a viscosity average molecular weight of 300,000 were used. 1 was performed to form a film having a thickness of 1.5 mm. The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. Table 1 shows the characteristics of the obtained film.
[0021]
[Comparative Example 1]
The same procedure as in Example 1 was conducted except that 23% by weight of fine silica and 54% by weight of dioctyl phthalate were mixed with a super mixer, and only 23% by weight of polyethylene having a viscosity average molecular weight of 400000 was used as the polyethylene. Molded into a 0 mm film. The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. The properties of the obtained film are shown in Table 2.
[0022]
[Comparative Example 2]
Example: Except that 23% by weight of fine silica and 54% by weight of dioctyl phthalate were mixed with a super mixer, and 9% by weight of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 3000000 and 14% by weight of polyethylene having a viscosity average molecular weight of 50000 were used. 1 was performed to form a film having a thickness of 1.2 mm. The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. The properties of the obtained film are shown in Table 2.
[0023]
[Comparative Example 3]
Example: Except that 23% by weight of fine silica and 54% by weight of dioctyl phthalate were mixed with a super mixer, and 1% by weight of ultrahigh molecular weight polyethylene having a viscosity average molecular weight of 3000000 and 22% by weight of polyethylene having a viscosity average molecular weight of 300000 were used. 1 was performed to form a film having a thickness of 1.2 mm. The formed film was immersed in methylene chloride for 20 minutes to extract dioctyl phthalate and then dried. The properties of the obtained film are shown in Table 2.
[0024]
[Table 1]
[Table 2]
【The invention's effect】
According to the present invention, a zinc bromine secondary battery separator having excellent heat resistance, stress crack resistance, excellent chemical resistance, excellent permeation performance, and having a homogeneous three-dimensional porous structure composed of fine pores. Is obtained.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03325996A JP3948762B2 (en) | 1996-02-21 | 1996-02-21 | Zinc bromine secondary battery separator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03325996A JP3948762B2 (en) | 1996-02-21 | 1996-02-21 | Zinc bromine secondary battery separator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09231957A JPH09231957A (en) | 1997-09-05 |
| JP3948762B2 true JP3948762B2 (en) | 2007-07-25 |
Family
ID=12381525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03325996A Expired - Lifetime JP3948762B2 (en) | 1996-02-21 | 1996-02-21 | Zinc bromine secondary battery separator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3948762B2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5948557A (en) * | 1996-10-18 | 1999-09-07 | Ppg Industries, Inc. | Very thin microporous material |
| US6849702B2 (en) | 1999-02-26 | 2005-02-01 | Robert W. Callahan | Polymer matrix material |
| US7129004B2 (en) | 2000-05-22 | 2006-10-31 | Asahi Kasei Kabushiki Kaisha | Separator for zinc/bromine secondary batteries and production process thereof |
| WO2001091207A1 (en) * | 2000-05-22 | 2001-11-29 | Asahi Kasei Kabushiki Kaisha | Separator for zinc bromine secondary cell and method for its preparation |
| US7081321B2 (en) | 2000-05-30 | 2006-07-25 | Asahi Kasei Kabushiki Kaisha | Separator for metal halogen cell |
| JP2002025532A (en) * | 2000-07-10 | 2002-01-25 | Asahi Kasei Corp | Separator for metal halogen battery |
| JP4877881B2 (en) * | 2000-08-07 | 2012-02-15 | 旭化成イーマテリアルズ株式会社 | Zinc halogen battery separator |
| KR101629944B1 (en) * | 2014-11-27 | 2016-06-13 | 롯데케미칼 주식회사 | Resin composition for preparing of porous membrane of zinc-bromine redox flow battery, preparation method for porous membrane of redox flow battery, and porous membrane of zinc-bromine redox flow battery |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60249266A (en) * | 1984-05-23 | 1985-12-09 | Meidensha Electric Mfg Co Ltd | Separator for zinc-bromine battery |
| JP2657434B2 (en) * | 1991-07-19 | 1997-09-24 | 東燃株式会社 | Polyethylene microporous membrane, method for producing the same, and battery separator using the same |
-
1996
- 1996-02-21 JP JP03325996A patent/JP3948762B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09231957A (en) | 1997-09-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4397121B2 (en) | Polyolefin microporous membrane | |
| US5641565A (en) | Separator for a battery using an organic electrolytic solution and method for preparing the same | |
| JP3305006B2 (en) | Battery separator using organic electrolyte and method for producing the same | |
| EP0547237B1 (en) | Separator of battery wherein organic electrolyte is used and production thereof | |
| JP2004196870A (en) | Polyolefin fine porous membrane and method for producing the same and use | |
| JP2004196871A (en) | Polyolefin fine porous membrane and method for producing the same and use | |
| JP2000017100A (en) | Preparation of polyethylene micro-porous membrane | |
| JP4271750B2 (en) | Microporous membrane and method for producing the same | |
| JPH09324067A (en) | Production of porous fluororesin | |
| JP5171012B2 (en) | Method for producing polyolefin microporous membrane | |
| JP3948762B2 (en) | Zinc bromine secondary battery separator | |
| JP3699562B2 (en) | Polyolefin microporous membrane and method for producing the same | |
| KR101354708B1 (en) | Method of manufacturing a multi-component separator film with ultra high molecule weight polyethylene for lithium secondary battery and a multi-component separator film for lithium secondary battery therefrom | |
| JP5592745B2 (en) | Polyolefin microporous membrane | |
| JP3699561B2 (en) | Polyolefin microporous membrane and method for producing the same | |
| JPH11269290A (en) | Polyoelfin fine porous membrane | |
| JP3121047B2 (en) | Homogeneous polyethylene microporous membrane and method for producing the same | |
| TW201840666A (en) | Microporous polyolefin membrane and battery including same | |
| JPS5859072A (en) | Porous film of thermoplastic resin and production thereof | |
| JP3497531B2 (en) | Microporous membrane coating | |
| JPH0693130A (en) | Production of microporous polyolefin film | |
| JPH09259858A (en) | Polyethylene micro-porous film for separator, and manufacture thereof | |
| JP4901050B2 (en) | Metal halide battery separator | |
| JPH04506224A (en) | microporous membrane | |
| JPH04212265A (en) | Polyethylene poromeric film for cell separator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20040525 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050823 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20051021 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20061128 |
|
| RD03 | Notification of appointment of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7423 Effective date: 20061226 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070123 |
|
| A911 | Transfer of reconsideration by examiner before appeal (zenchi) |
Free format text: JAPANESE INTERMEDIATE CODE: A911 Effective date: 20070308 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070417 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070417 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100427 Year of fee payment: 3 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100427 Year of fee payment: 3 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100427 Year of fee payment: 3 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100427 Year of fee payment: 3 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110427 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110427 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120427 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120427 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130427 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130427 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140427 Year of fee payment: 7 |
|
| EXPY | Cancellation because of completion of term |