JP2005232289A - Porous film - Google Patents
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- JP2005232289A JP2005232289A JP2004042614A JP2004042614A JP2005232289A JP 2005232289 A JP2005232289 A JP 2005232289A JP 2004042614 A JP2004042614 A JP 2004042614A JP 2004042614 A JP2004042614 A JP 2004042614A JP 2005232289 A JP2005232289 A JP 2005232289A
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- 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
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
Description
本発明は、多孔質フィルム及びその各種用途に関する。さらに詳しくは、膜性能および機械的強度に優れると共に、特に高温下での厚み維持性に優れた多孔質フィルム、該多孔質フィルムからなる非水電解液電池用セパレータ、該セパレータを用いてなる非水電解液電池、該多孔質フィルムからなる電解質膜、該電解質膜を用いてなる固体高分子型燃料電池に関する。 The present invention relates to a porous film and various uses thereof. More specifically, the porous film has excellent membrane performance and mechanical strength, and is particularly excellent in maintaining the thickness at high temperatures, a separator for a non-aqueous electrolyte battery comprising the porous film, and a non-aqueous electrolyte using the separator. The present invention relates to a water electrolyte battery, an electrolyte membrane made of the porous film, and a polymer electrolyte fuel cell using the electrolyte membrane.
リチウムなどの軽金属を電極とする非水電解液電池は、エネルギー密度が高く自己放電も少ないため、電子機器の高性能化、小型化などを背景として利用範囲を大きく広げてきている。このような非水電解液電池の電極としては帯状の正極、負極、およびセパレータを積層し巻回して構成することにより、広い有効電極面積を確保した渦巻状巻回体が用いられている。セパレータは、基本的には両極の短絡を防止するとともに、その多孔質構造によりイオンを透過させて電池反応を可能とするものであるが、誤接続などにより異常電流が発生した場合に電池内部温度の上昇に伴い樹脂が熱変形して多孔質を防ぎ電池反応を停止させる、いわゆるシャットダウン機能(SD機能)を有するものが安全性向上の観点から採用されている。 Non-aqueous electrolyte batteries using light metals such as lithium as electrodes have a high energy density and low self-discharge, and thus have a wide range of applications against the background of high performance and miniaturization of electronic devices. As the electrode of such a non-aqueous electrolyte battery, a spiral wound body that secures a wide effective electrode area by stacking and winding a belt-like positive electrode, a negative electrode, and a separator is used. The separator basically prevents short-circuiting of both electrodes and allows the battery reaction by allowing ions to permeate due to its porous structure. However, when an abnormal current occurs due to misconnection or the like, the internal temperature of the battery A resin having a so-called shut-down function (SD function) that stops the battery reaction by preventing the resin from being thermally deformed as the temperature rises is adopted from the viewpoint of improving safety.
このようなSD機能を有するセパレータとしては、例えば、ポリエチレン製多孔質膜やポリエチレンとポリプロピレンとの多層構造の多孔質膜などが知られている。 As a separator having such an SD function, for example, a polyethylene porous film or a porous film having a multilayer structure of polyethylene and polypropylene is known.
しかしながら、昨今のリチウムイオン二次電池などの進歩により、上記シャットダウン機能のみならず、耐熱的な要素、すなわち、シャットダウン後にさらに温度が上昇した時に、セパレータ自身が溶融破膜(メルトダウン)したり、溶融まで至らない場合でも厚みが減少して破断する状態がおこり得ることを考慮すると、より高い温度で対応できることが望まれている。特に、高容量化された電池や電池内部抵抗の低減がすすむと、発熱が大きくなる要素が増すため、ますます重要である。 However, due to recent advances in lithium ion secondary batteries and the like, not only the above shutdown function, but also a heat-resistant element, that is, when the temperature further rises after shutdown, the separator itself melts (breaks down), In consideration of the possibility that a state where the thickness is reduced and fractures can occur even when melting does not occur, it is desired to be able to cope with a higher temperature. In particular, if the capacity of the battery is increased or the internal resistance of the battery is reduced, the factors that increase the heat generation increase, which is more important.
上記問題に対してはシャットダウン温度と破膜温度の差が大きく、また、破膜温度が高いほど、高温特性が良好で安全性の高い電池用セパレータになりうると考えられる。例えば、低融点ポリエチレンと高融点のポリプロピレンからなる単膜を積層化することにより、高強度かつ優れた高温特性を有する微孔性多孔膜を得る方法が開示されているが(例えば、特許文献1参照)、積層のためセパレータの内部抵抗が高くなり、高出力用途など高性能電池に対するセパレータとしては不向きである。 For the above problem, it is considered that the difference between the shutdown temperature and the membrane breaking temperature is large, and that the higher the membrane breaking temperature, the better the high temperature characteristics and the higher the safety of the battery separator. For example, a method of obtaining a microporous porous film having high strength and excellent high temperature characteristics by laminating a single film made of low melting point polyethylene and high melting point polypropylene is disclosed (for example, Patent Document 1). For example, the internal resistance of the separator is increased due to the lamination, and it is not suitable as a separator for a high-performance battery such as a high-power application.
また、低分子量ポリエチレンとポリプロピレンを含有した高分子量ポリエチレン組成物からなる多孔質膜を得る方法が開示されているが(例えば、特許文献2参照)、急激に温度が上昇する場合には大部分を占めるポリエチレン素材が容易に溶融するため厚みが減少し破断しやすくなり危険性が大きくなる。 Moreover, although the method of obtaining the porous membrane which consists of a high molecular weight polyethylene composition containing low molecular weight polyethylene and a polypropylene is disclosed (for example, refer patent document 2), when temperature rises rapidly, most are Since the polyethylene material that it occupies easily melts, its thickness decreases, it becomes easy to break, and the danger increases.
つまり、電解液、電解質とともに高温にさらされる場合では、溶融だけでなく、酸化劣化的な作用で分子切断などが起こり、ポリマー素材の劣化が大きくなって破膜に至る場合が想定されるため、高温での厚みの維持機能は重要となる。リチウムイオン電池など非水電解液電池は、150℃での耐熱を想定して検討されることが多いが、異常発熱がある場合150〜180℃にまで上昇することがあり、180℃で耐劣化性をもち、厚み維持機能をもつことは安全性に大きく寄与できることになる。 In other words, when exposed to a high temperature together with the electrolyte and electrolyte, it is assumed that not only melting but also molecular cutting occurs due to oxidative degradation, resulting in significant degradation of the polymer material leading to membrane breakage. The function of maintaining the thickness at high temperatures is important. Non-aqueous electrolyte batteries such as lithium ion batteries are often considered assuming heat resistance at 150 ° C., but may rise to 150 to 180 ° C. when there is abnormal heat generation and deteriorate at 180 ° C. Having a thickness and having a thickness maintaining function can greatly contribute to safety.
このため、本発明者らはポリオレフィン系樹脂からなる多孔質フィルムを新規な方法で架橋処理する技術を発明し、高強度かつ、高耐熱性の多孔質フィルムの開発に成功した(特許文献3参照)。これにより、高温での溶融等による破膜の問題は解決するに至った。 For this reason, the present inventors invented a technique for crosslinking a porous film made of polyolefin resin by a novel method, and succeeded in developing a porous film having high strength and high heat resistance (see Patent Document 3). ). As a result, the problem of film breakage due to melting at a high temperature or the like has been solved.
しかしながら、上記のような架橋構造を有する多孔質フィルムを使用した場合でも、実際に実電池に組み込まれた場合、150〜180℃付近の高温に電池を長時間曝した際には、実電池の組み方が緩いなど構成によっては端部の収縮などによって電極間のショート(短絡)が起こり得る可能性があった。
そこで、本発明の目的は、膜性能および機械的強度に優れると共に、高温下での耐熱破膜性や厚み維持性に優れた多孔質フィルム、およびその各種用途を提供することにある。 Therefore, an object of the present invention is to provide a porous film excellent in film performance and mechanical strength, and excellent in heat-resistant film breaking property and thickness maintenance at high temperatures, and various uses thereof.
本発明者らは、上記目的を達成すべく鋭意研究したところ、架橋構造を有するポリオレフィン系の多孔質フィルムにおいて、SD成分の種類やポリオレフィン系樹脂との組成比などを適切にコントロールすることで、特に高温下での厚み維持性が改善できることを見出し、本発明を完成するに至った。 The inventors of the present invention have intensively studied to achieve the above object, and in the polyolefin porous film having a crosslinked structure, by appropriately controlling the type of SD component and the composition ratio with the polyolefin resin, In particular, the present inventors have found that the thickness maintainability at a high temperature can be improved and have completed the present invention.
即ち、本発明の多孔質フィルムは、ポリオレフィン系樹脂を含有する樹脂組成物を架橋してなり、厚み5μm〜40μm、空孔率20〜70%の多孔質フィルムであって、正極および負極間に挿入して電解液を含浸させてからガラス板で上下から挟み込み、180℃で90分加熱後に冷却して取り出した後、針入プローブ式熱機械的分析装置を用いて、プローブ径1mmφ、70g荷重、室温より昇温速度2℃/minで測定したときの厚み変化において、荷重後の厚み維持率が180℃で50%以上であることを特徴とする。 That is, the porous film of the present invention is a porous film having a thickness of 5 μm to 40 μm and a porosity of 20 to 70%, which is formed by crosslinking a resin composition containing a polyolefin resin. Inserted and impregnated with electrolyte solution, sandwiched from above and below by glass plate, heated at 180 ° C for 90 minutes, cooled and taken out, then probed with a probe diameter of 1mmφ, 70g load In the change in thickness when measured from room temperature at a rate of temperature increase of 2 ° C./min, the thickness retention rate after loading is 50% or more at 180 ° C.
このような厚み維持性を有することによって、実際に電池に組み込んで150〜180℃の高温に電池を長時間曝した場合でも、酸化劣化などによって破膜が促進されにくいものとなる。 By having such a thickness maintaining property, even when the battery is actually incorporated into a battery and exposed to a high temperature of 150 to 180 ° C. for a long time, the film breakage is hardly promoted due to oxidative degradation or the like.
上記において、前記樹脂組成物が、重量平均分子量50万以上である超高分子量ポリエチレン、グラフト重合ポリエチレンおよび分子内に二重結合を含有する樹脂成分を含有することが好ましい。グラフト重合ポリエチレンを含有することにより、所望のSD特性が得られやすくなるだけでなく、超高分子量ポリエチレンとの絡み合いを維持しながら、応力などの緩和を行うため、膜性能および機械的強度を改善しながら、更に高温下での厚み維持性が改善できるようになるものと考えられる。すなわち、グラフト重合ポリエチレンと超高分子量ポリエチレンの組成比などを適切に調整することにより、大きな収縮応力が作用する前に緩和が起こるために強度維持と耐破膜・収縮性を有すると考えられる。この詳細なメカニズムは不明だが、グラフト重合化されたポリエチレンにより、構造を維持する結晶性が容易に崩れないことと、部分的な溶融性による応力緩和が両立していることが考えられる。 In the above, it is preferable that the resin composition contains an ultrahigh molecular weight polyethylene having a weight average molecular weight of 500,000 or more, a graft-polymerized polyethylene, and a resin component containing a double bond in the molecule. The inclusion of graft-polymerized polyethylene not only makes it easier to obtain the desired SD characteristics, but also improves membrane performance and mechanical strength to maintain stresses while maintaining entanglement with ultrahigh molecular weight polyethylene. However, it is considered that the thickness maintainability at a higher temperature can be improved. That is, by appropriately adjusting the composition ratio of the graft-polymerized polyethylene and the ultra-high molecular weight polyethylene, etc., it is considered that relaxation occurs before a large contraction stress acts, so that the strength is maintained and the film has resistance to tearing and shrinkage. Although the detailed mechanism is unknown, it is conceivable that the graft-polymerized polyethylene can easily maintain the crystallinity for maintaining the structure and can relieve stress due to partial meltability.
その際、前記グラフト重合ポリエチレンが無水マレイン酸グラフト重合ポリエチレンであることが好ましい。また、前記分子内に二重結合を含有する樹脂成分が、ポリノルボルネン、EPDM、ポリブタジエン、及びエポキシ化ポリスチレンブタジエンからなる群より選ばれる1種以上であることが好ましい。 In that case, it is preferable that the graft-polymerized polyethylene is maleic anhydride graft-polymerized polyethylene. Moreover, it is preferable that the resin component containing a double bond in the molecule is at least one selected from the group consisting of polynorbornene, EPDM, polybutadiene, and epoxidized polystyrene butadiene.
一方、本発明の電池用セパレータは、上記いずれかに記載の多孔質フィルムを用いてなるものである。また、本発明の非水電解液電池は、かかる電池用セパレータを用いてなるものである。本発明の多孔質フィルムは、上記のように、膜性能および機械的強度に優れると共に、高温下での耐熱破膜性や厚み維持性に優れるため、電池特性および安全性に優れた、様々な大きさや用途の電池をえることができる。 On the other hand, the battery separator of the present invention is formed using any of the porous films described above. The non-aqueous electrolyte battery of the present invention uses such a battery separator. As described above, the porous film of the present invention is excellent in membrane performance and mechanical strength, as well as excellent in heat-resistant film-breaking property and thickness maintenance at high temperatures, and thus has various battery properties and safety. A battery of a size and application can be obtained.
他方、本発明の電解質膜は、上記いずれかに記載の多孔質フィルムが高分子電解質を担持してなるものである。また、本発明の固体高分子型燃料電池は、かかる電解質膜を用いてなるものである。本発明の多孔質フィルムは、上記のように、膜性能および機械的強度に優れると共に、高温下での耐熱破膜性や厚み維持性に優れるため、電解質膜に使用することで、高分子電解質を担持した際にイオン伝導性が良好で、高い耐久性を有する固体高分子型燃料電池が得られる。 On the other hand, the electrolyte membrane of the present invention is one in which the porous film described above carries a polymer electrolyte. Moreover, the polymer electrolyte fuel cell of the present invention uses such an electrolyte membrane. As described above, the porous film of the present invention is excellent in membrane performance and mechanical strength, and is excellent in heat-resistant film breaking property and thickness maintenance at high temperatures. Thus, a solid polymer fuel cell having good ion conductivity and high durability when loaded with is obtained.
以下、本発明の実施の形態について説明する。 Embodiments of the present invention will be described below.
本発明において用いる多孔質フィルムは、耐熱試験として、正極および負極間に挿入して電解液を含浸させてからガラス板で上下から挟み込み、180℃で90分加熱後に冷却して取り出した後、針入プローブ式熱機械的分析装置を用いて、プローブ径1mmφ、70g荷重、室温より昇温速度2℃/minで測定したときの厚み変化において、荷重後の厚み維持率が180℃で50%以上であることを特徴とする。膜厚維持にも優れ高温での絶縁膜としての機能を有する観点から、当該厚み維持率が60%以上が好ましい。 As a heat resistance test, the porous film used in the present invention was inserted between a positive electrode and a negative electrode, impregnated with an electrolytic solution, sandwiched from above and below by a glass plate, heated at 180 ° C. for 90 minutes, cooled and taken out, then needles Using a probe-type thermomechanical analyzer, the thickness maintenance ratio after loading is 50% or more at 180 ° C. in the change in thickness when measured with a probe diameter of 1 mmφ, 70 g load, and a temperature rising rate of 2 ° C./min from room temperature. It is characterized by being. From the viewpoint of excellent film thickness maintenance and a function as an insulating film at high temperature, the thickness maintenance rate is preferably 60% or more.
上記の耐熱試験は、実電池において180℃まで昇温した場合を想定したときのセパレータとしての多孔質フィルムの状態を鑑みて行うものである。正極および負極間に挿入し、電解液を含浸させて後、ガラス板で上下から挟み込み、180℃、90分加熱を行い、冷却後に電極間から多孔質フィルムを取り出す。この時点において、多孔質フィルムの材質によっては著しく可塑化して劣化の著しいものがみられる。孔閉塞したフィルムを電極面から剥離して水洗後、針入プローブ式熱機械的分析装置を用いて、高温時の熱挙動、すなわち電極間にはさまれ、電解液、電解質の熱分解等の作用によって起こりうる多孔質フィルムの劣化状態を評価する。 The above heat resistance test is performed in view of the state of the porous film as a separator when assuming a case where the temperature is increased to 180 ° C. in an actual battery. After being inserted between the positive electrode and the negative electrode and impregnated with the electrolytic solution, the glass film is sandwiched from above and below, heated at 180 ° C. for 90 minutes, and after cooling, the porous film is taken out between the electrodes. At this point, depending on the material of the porous film, there is a significant plasticization and significant deterioration. After peeling the hole-occluded film from the electrode surface and washing it with water, using a probe probe thermomechanical analyzer, the thermal behavior at high temperature, that is, sandwiched between the electrodes, The deterioration state of the porous film that may occur due to the action is evaluated.
このとき、針入プローブ式熱機械的分析装置を通してみられる現象について説明する。まず、孔閉塞した多孔質フィルムに荷重のかかった針径1mmφの円筒型針をセットすると、荷重により幾分厚みが減少し、その後安定する。この時点を初期値にとり、昇温につれ厚みが変化していく挙動を観察することにより高温での劣化状態を確認することができる。孔閉塞した多孔質フィルムは昇温とともに弾性率が下がり少しづつ減少していくが、さらに昇温していくと、大きく厚みが低下する温度域(100〜150℃)になる。これは、ポリオレフィン材料に基づく結晶が溶融する部分と、その分子切断などによる劣化により大きくフィルム厚が減少していく部分と考えられる。耐熱性が高い多孔質フィルムでは、上記孔閉塞後も膜厚を維持する傾向が強い。この厚み維持率として180℃で50%以上の残存厚みがあれば、実電池での安全性を評価する150℃耐熱試験においても対応できるものと考えられる。 At this time, a phenomenon observed through the penetration probe type thermomechanical analyzer will be described. First, when a loaded cylindrical needle having a needle diameter of 1 mmφ is set on the porous film in which the hole is closed, the thickness is somewhat reduced by the load, and then stabilized. By taking this time as an initial value and observing the behavior in which the thickness changes as the temperature rises, the deterioration state at a high temperature can be confirmed. As the temperature rises, the modulus of elasticity of the porous film closed by the pores decreases and gradually decreases. However, as the temperature is further increased, the temperature range (100 to 150 ° C.) decreases greatly. This is considered to be a part where the crystal based on the polyolefin material melts and a part where the film thickness is greatly reduced due to deterioration due to molecular cutting or the like. A porous film with high heat resistance has a strong tendency to maintain the film thickness even after the pores are closed. If there is a remaining thickness of 50% or more at 180 ° C. as the thickness maintenance ratio, it is considered that the 150 ° C. heat resistance test for evaluating the safety of an actual battery can be used.
上記の多孔質フィルムの厚みとしては5〜40μm、好ましくは5〜30μmである。その空孔率としては、20〜70%、好ましくは20〜60%である。 The thickness of the porous film is 5 to 40 μm, preferably 5 to 30 μm. The porosity is 20 to 70%, preferably 20 to 60%.
本発明の多孔質フィルムは、ポリオレフィン系樹脂を含有する樹脂組成物を架橋してなる。樹脂組成物には、ポリエチレン、ポリプロピレン、ポリブチレンなどのポリオレフィン樹脂、カルボニル基や酸無水物基などがグラフト重合されたポリオレフィン類など含有することができる。グラフト重合されたポリオレフィン類としては、たとえば、高密度ポリエチレン、低密度ポリエチレン、ポリプロピレン、EVA等があげられるが、相溶性などの点から無水マレイン酸グラフトポリエチレンが好ましい。無水マレイン酸がグラフトされる前のポリオレフィン類の分子量としては、好ましくは重量平均分子量で1万〜50万、より好ましくは5万〜30万である。このグラフト重合されたポリオレフィン類は、全樹脂成分中、10〜69重量%が好ましく、15〜60重量%がより好ましい。 The porous film of the present invention is formed by crosslinking a resin composition containing a polyolefin resin. The resin composition can contain polyolefin resins such as polyethylene, polypropylene, and polybutylene, and polyolefins graft-polymerized with a carbonyl group or an acid anhydride group. Examples of the graft-polymerized polyolefins include high-density polyethylene, low-density polyethylene, polypropylene, EVA and the like, and maleic anhydride-grafted polyethylene is preferable from the viewpoint of compatibility. The molecular weight of the polyolefins before being grafted with maleic anhydride is preferably 10,000 to 500,000, more preferably 50,000 to 300,000 in terms of weight average molecular weight. The graft-polymerized polyolefin is preferably 10 to 69% by weight, more preferably 15 to 60% by weight, based on all resin components.
電池用セパレータとして用いる場合には、ポリオレフィン類とポリブタジエンやポリノルボルネン、EPDMゴム、エポキシ化ポリスチレンブタジエンなど分子鎖に二重結合を有する樹脂成分(架橋性ゴムを含む)を含有させ潜在的架橋性をもたせたり、後工程により架橋処理を行うなど、特に架橋処理を施すことにより高い熱破膜性、膜厚維持性が期待できる。これらの反応性樹脂材料は単独で加えてもよいし、複数組み合わせてもよい。分子鎖に二重結合を有する樹脂成分の含有量は、全樹脂成分中、1〜50重量%が好ましく、3〜40重量%がより好ましい。 When used as a battery separator, it contains a resin component (including crosslinkable rubber) having a double bond in the molecular chain such as polyolefins and polybutadiene, polynorbornene, EPDM rubber, epoxidized polystyrene butadiene, etc. High thermal breakability and film thickness maintainability can be expected by carrying out the crosslinking treatment, for example, by giving it a cross-linking treatment in a subsequent process. These reactive resin materials may be added alone or in combination. The content of the resin component having a double bond in the molecular chain is preferably 1 to 50% by weight, and more preferably 3 to 40% by weight in all the resin components.
ポリオレフィン系樹脂としては超高分子量ポリエチレンを含有していることが、機械強度的にも好ましく、好ましくは50万以上の重量平均分子量、より好ましくは100万以上の重量平均分子量である。その樹脂成分中、40重量%以上、特に50〜90重量%が超高分子量ポリエチレンであることが好ましい。 The polyolefin resin preferably contains ultra high molecular weight polyethylene in terms of mechanical strength, preferably 500,000 or more, more preferably 1,000,000 or more. In the resin component, 40% by weight or more, particularly 50 to 90% by weight, is preferably ultrahigh molecular weight polyethylene.
次に、本発明による多孔質フィルムの製造方法について説明する。本発明によるセパレータ用多孔質フィルムの製造には、乾式成膜法、湿式成膜法など公知の方法を利用することができる。たとえば、前記樹脂組成物を溶媒と混合し、混練、加熱溶解しながらシート状に成形した後、圧延し、一軸方向以上に延伸し、溶媒を抽出除去することにより製造することができる。また、架橋性ゴムを含有した多孔質フィルムの二重結合部位を熱、紫外線、電子線等の架橋処理により耐熱性を付与することもできる。 Next, the manufacturing method of the porous film by this invention is demonstrated. For the production of the porous film for a separator according to the present invention, a known method such as a dry film forming method or a wet film forming method can be used. For example, it can be produced by mixing the resin composition with a solvent, forming into a sheet while kneading and heating and dissolving, rolling, stretching in a uniaxial direction or more, and extracting and removing the solvent. Moreover, heat resistance can also be provided to the double bond site | part of the porous film containing crosslinking | crosslinked rubber | gum by bridge | crosslinking processes, such as a heat | fever, an ultraviolet-ray, and an electron beam.
このように本発明による多孔質フィルムは、シャットダウン(膜孔閉塞)後の高温条件下において膜厚維持性に優れて、容易に破膜しない電池用セパレータとして安全性を向上させることが期待できる。 Thus, the porous film according to the present invention can be expected to improve safety as a battery separator that is excellent in film thickness maintainability under a high temperature condition after shutdown (membrane pore occlusion) and does not easily break.
またその強度、劣化に強い特性から、燃料電池用の固体高分子電解質膜の基材としても用いることができる。 Moreover, it can be used as a base material for a solid polymer electrolyte membrane for a fuel cell because of its strength and resistance to deterioration.
次に本発明の非水電解液電池について説明する。当該非水電解液電池は、以上の如き多孔質フィルムからなるセパレータを用いてなり、その構造は、例えば帯状の負極、正極およびセパレータを積層捲回して得た捲回型電極体を電池缶に収納し、これに電解液を注入し、さらに電池上下の絶縁板など必要な部材を市販の電池に準じて適宜配して構成したものである。 Next, the nonaqueous electrolyte battery of the present invention will be described. The non-aqueous electrolyte battery uses a separator made of the porous film as described above, and the structure thereof is, for example, a wound electrode body obtained by laminating and winding a strip-shaped negative electrode, a positive electrode, and a separator in a battery can. The battery is housed, an electrolyte is poured into it, and necessary members such as insulating plates above and below the battery are appropriately arranged according to a commercially available battery.
電解液としては、例えば、リチウム塩を電解液とし、これを有機溶媒に溶解した電解液が用いられる。有機溶媒としては、特に限定されるものではないが、たとえば、プロピレンカーボネート、エチレンカーボネート、ブチレンカーボネート、γ−ブチロラクトン、γ−バレロラクトン、ジメチルカーボネート、プロピオン酸メチル、酢酸ブチルなどのエステル類、アセトニトリル等のニトリル類、1,2−ジメトキシエタン、1,2−ジメトキシメタン、ジメトキシプロパン、1,3−ジオキソラン、テトラヒドロフラン、2−メチルテトラヒドロフラン、4−メチル−1,3−ジオキソランなどのエーテル類、さらにはスルフォランなどの単独、もしくは二種類以上の混合溶媒が使用できる。 As the electrolytic solution, for example, an electrolytic solution in which a lithium salt is used as an electrolytic solution and this is dissolved in an organic solvent is used. Although it does not specifically limit as an organic solvent, For example, propylene carbonate, ethylene carbonate, butylene carbonate, (gamma) -butyrolactone, (gamma) -valerolactone, dimethyl carbonate, methyl propionate, butyl acetate ester, acetonitrile, etc. Nitriles, 1,2-dimethoxyethane, 1,2-dimethoxymethane, dimethoxypropane, 1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, ethers such as 4-methyl-1,3-dioxolane, A single solvent such as sulfolane or a mixed solvent of two or more kinds can be used.
負極としてはアルカリ金属またはアルカリ金属を含む化合物をステンレス鋼製網などの集電材料と一体化したものが用いられる。その際のアルカリ金属として、たとえばリチウム、ナトリウム、カリウムなどが挙げられ、アルカリ金属を含む化合物としては、たとえばアルカリ金属とアルミニウム、鉛、インジウム、カリウム、カドミウム、スズ、マグネシウムなどの合金、さらにはアルカリ金属と炭素材料との化合物、低電位のアルカリ金属と金属酸化物、硫化物との化合物などが挙げられる。負極に炭素材料を用いる場合、炭素材料としては、リチウムイオンをドープ、脱ドープできるものであればよく、たとえば、黒鉛、熱分解炭素類、コークス類、ガラス状炭素類、有機高分子化合物の焼成体、メソカーボンマイクロビーズ、炭素繊維、活性炭などを用いることができる。 As the negative electrode, an alkali metal or a compound containing an alkali metal integrated with a current collecting material such as a stainless steel net is used. In this case, examples of the alkali metal include lithium, sodium, and potassium. Examples of the compound containing the alkali metal include alkali metal and alloys such as aluminum, lead, indium, potassium, cadmium, tin, and magnesium, and alkali. Examples thereof include a compound of a metal and a carbon material, a compound of a low potential alkali metal and a metal oxide, and a sulfide. When a carbon material is used for the negative electrode, the carbon material may be any material that can be doped and dedoped with lithium ions. For example, graphite, pyrolytic carbons, cokes, glassy carbons, and firing organic polymer compounds Bodies, mesocarbon microbeads, carbon fibers, activated carbon, and the like can be used.
正極としては、たとえばリチウムコバルト酸化物、リチウムニッケル酸化物、リチウムマンガン酸化物、二酸化マンガン、五酸化バナジウム、クロム酸化物、などの金属酸化物、二硫化モリブデンなどの金属窒化物などが活物質として用いられ、これらの正極活物質に導電助剤やポリテトラフルオロエチレンなどの結着剤などを適宜添加した合剤を、ステンレス鋼製網などの集電材料を芯材として成形体に仕上げたものが用いられる。 As the positive electrode, for example, metal oxides such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, manganese dioxide, vanadium pentoxide, and chromium oxide, and metal nitrides such as molybdenum disulfide are used as active materials. A mixture of these positive electrode active materials with conductive additives and binders such as polytetrafluoroethylene added as appropriate, and finished into a molded body using a current collector material such as a stainless steel net as a core material Is used.
次に本発明の固体高分子型燃料電池について説明する。固体高分子型燃料電池の構造は、一般的に、プロトン伝導性を有する固体高分子電解質膜を挟んでアノードとカソードとを配設し、さらに、ガスケットを介して一対のセパレータにより挟持して単位セルを構成し、この単位セルを多数個積層し、単位セルどうしを電気的に直列に接続して燃料電池を構成している。 Next, the polymer electrolyte fuel cell of the present invention will be described. The structure of a polymer electrolyte fuel cell is generally a unit in which an anode and a cathode are disposed with a proton-conducting polymer electrolyte membrane sandwiched, and further sandwiched by a pair of separators via a gasket. A cell is constituted, a large number of unit cells are stacked, and unit cells are electrically connected in series to constitute a fuel cell.
固体高分子電解質膜は、本発明の多孔質フィルムが高分子電解質を担持したものであり、例えば、多孔質フィルムの空孔内にポリマーを含浸させた後、このポリマーにスルホン酸基、プロトン化アミノ基、カルボキシル基等のイオン交換基を導入したものや、イオン交換基を有するモノマーを多孔質フィルムの空孔内に含浸させた後、モノマーを重合して高分子電解質を担持させたもの、更に担持した高分子電解質が架橋構造を有するもの、などが挙げられる。 The solid polymer electrolyte membrane is one in which the porous film of the present invention carries a polymer electrolyte. For example, after impregnating a polymer in the pores of the porous film, the polymer is sulfonated and protonated. Those in which an ion exchange group such as an amino group or a carboxyl group is introduced, or a monomer having an ion exchange group is impregnated in the pores of the porous film, and then the monomer is polymerized to carry a polymer electrolyte, Further, the supported polymer electrolyte has a crosslinked structure.
以下に実施例および比較例をあげて本発明を説明するが、本発明はこれら実施例により何ら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。 The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, the test method in an Example is as follows.
(重量平均分子量)
ウォーターズ社製のゲル浸透クロマトグラフ[GPC−150C]を用い、溶媒にo−ジクロロベンゼンを、また、カラムとして昭和電工(株)製の[Shodex−80M]を用いて135℃で測定する。データ処理は、TRC社製データ収集システムを用いて行なう。分子量はポリスチレンを基準として算出する。
(Weight average molecular weight)
A gel permeation chromatograph [GPC-150C] manufactured by Waters Co., Ltd. is used, o-dichlorobenzene is used as a solvent, and [Shodex-80M] manufactured by Showa Denko KK is used as a column at 135 ° C. Data processing is performed using a data collection system manufactured by TRC. The molecular weight is calculated based on polystyrene.
(架橋構造の確認)
IRスペクトル中のC=C二重結合に由来する吸収ピーク(960cm-1)の消失を確認した。また、10mm角の試料を金属メッシュに挟んで熱キシレン(255℃)中で溶解させ、残存する成分の比率をゲル分率として測定し、熱処理前の多孔質フィルムのゲル分率(通常は0%)と比較した。
(Confirmation of cross-linked structure)
The disappearance of the absorption peak (960 cm −1 ) derived from the C═C double bond in the IR spectrum was confirmed. In addition, a 10 mm square sample was sandwiched between metal meshes and dissolved in hot xylene (255 ° C.), and the ratio of the remaining components was measured as the gel fraction. The gel fraction of the porous film before heat treatment (usually 0) %).
(フィルム厚)
1/10000 直読ダイヤル式膜厚測定器により測定した。
(Film thickness)
1 / 10,000 Measured with a direct reading dial type film thickness measuring instrument.
(通気度)
JIS P8117に準拠して測定した。
(Air permeability)
It measured based on JISP8117.
(収縮率)
一定の面積に打ち抜いたセパレータについて、加熱前の面積S1 と、120℃で1時間乾燥機中にて加熱後の面積S2 をスキャナで読みとり、次式:
収縮率S=(S1 −S2 )/S1
にて120℃における面積収縮率を算出した。
(Shrinkage factor)
For the separator punched out to a certain area, the area S 1 before heating and the area S 2 after heating in a dryer at 120 ° C. for 1 hour are read with a scanner, and the following formula:
Shrinkage rate S = (S 1 −S 2 ) / S 1
The area shrinkage rate at 120 ° C. was calculated.
(針突刺強度)
針刺し強度はカトーテック(株)製,圧縮試験機KES‐G5を使用して針突き刺し試験を行い、測定により得られた荷重変位曲線より最大荷重を読みとって針刺強度値とした。針は直径0.5mm、先端曲率半径0.25mmを用い、2cm/秒の速度で行った。
(Needle puncture strength)
The needle puncture strength was determined by performing a needle puncture test using a compression tester KES-G5 manufactured by Kato Tech Co., Ltd., and reading the maximum load from the load displacement curve obtained by the measurement to obtain a needle puncture strength value. The needle had a diameter of 0.5 mm and a tip curvature radius of 0.25 mm, and was performed at a speed of 2 cm / sec.
(シャットダウン温度)
25mmφの筒状の試験室を有し、試験室が密閉可能なSUS製のセルを用い、下部電極はφ20mm、上部電極は10mmφの白金板(厚さ1.0mm)を使用した。24mmφに打ち抜いた測定試料を電解液に浸漬して電解液を含浸し、電極間に挟み、セルにセットした。電極はセルに設けられたばねにて一定の面圧がかかるようにした。電解液はプロピレンカーボネートとジメトキシエタンを容量比で1:1の割合で混合した溶媒に、ホウフッ化リチウムを1.0mol/Lの濃度になるように溶解したものを用いた。
(Shutdown temperature)
A SUS cell having a cylindrical test chamber of 25 mmφ and capable of sealing the test chamber was used, a platinum electrode (thickness: 1.0 mm) of 10 mmφ was used for the lower electrode and the upper electrode was φ20 mm. A measurement sample punched to 24 mmφ was immersed in an electrolytic solution, impregnated with the electrolytic solution, sandwiched between electrodes, and set in a cell. A certain surface pressure was applied to the electrode by a spring provided in the cell. The electrolytic solution used was a solution in which lithium borofluoride was dissolved to a concentration of 1.0 mol / L in a solvent in which propylene carbonate and dimethoxyethane were mixed at a volume ratio of 1: 1.
このセルに熱伝対温度計と、抵抗計を接続して温度と抵抗を測定できるようにし、180℃恒温器中へ投入し、温度と抵抗を測定した。100〜150℃の平均昇温速度は10℃/分であった。この測定により、抵抗が100Ω・cm2 に達した時の温度をシャットダウン温度とした。 A thermocouple thermometer and a resistance meter were connected to the cell so that the temperature and resistance could be measured. The temperature and resistance were measured by placing the cell in a 180 ° C. thermostat. The average temperature increase rate from 100 to 150 ° C. was 10 ° C./min. By this measurement, the temperature when the resistance reached 100 Ω · cm 2 was defined as the shutdown temperature.
(180℃厚み維持率)
縦100mm、横100mm、厚さ1mmのガラス板の中心に、縦60mm、横20mmに切り出した負極を置き、その上に縦64mm、横24mmの多孔質フィルムを縦横2mmずつはみ出すように置いた。更に縦60mm、横20mmに切り出した正極を負極と重ね合わせるように置いて多孔質フィルムを挟み込んだ。なお、上記各正極および負極、多孔質フィルムは予め、電解液(エチレンカーボネート、ジエチレンカーボネートの1:1溶液に、1mol/lのLiClO4 過塩素酸リチウムを電解質として加えたもの)を含浸させておいた。更に縦100mm、横100mm、厚さ1 mmのガラス板を重ね合わせて、その中心に縦横60mmの420gの金属おもりを載せ、加重をかけたものを1セットとしてステンレストレイ中に置き蓋をして乾燥機中で昇温速度10℃/分で加熱し、180℃到達後90分保持した。
(180 ° C thickness maintenance rate)
A negative electrode cut to a length of 60 mm and a width of 20 mm was placed at the center of a glass plate having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm, and a porous film having a length of 64 mm and a width of 24 mm was placed on the negative electrode. Furthermore, the positive electrode cut out to 60 mm in length and 20 mm in width was put so that it might overlap with a negative electrode, and the porous film was pinched | interposed. Each of the positive electrode, the negative electrode, and the porous film is impregnated in advance with an electrolytic solution (1 mol / l LiClO 4 lithium perchlorate added as an electrolyte to a 1: 1 solution of ethylene carbonate and diethylene carbonate). Oita. Furthermore, a glass plate with a length of 100 mm, a width of 100 mm, and a thickness of 1 mm is overlaid, and a 420 g metal weight with a length of 60 mm is placed in the center. The mixture was heated in a dryer at a heating rate of 10 ° C./min and held for 90 minutes after reaching 180 ° C.
乾燥機から取り出し冷却後、多孔質フィルムを取り出して針入プローブ式熱機械的分析装置用の試料とした。なお、用いた正極はリチウムコバルト酸化物(LiClO2 )に導電助剤としてリン状黒鉛を重量比90:5で加えて混合し、この混合物と、ポリフッ化ビニリデンをN‐メチルピロリドンに溶解させた溶液とを混合してスラリーにした。この正極合剤スラリーを70メッシュの網を通過させて大きなものを取り除いた後、厚さ20μmのアルミニウム箔からなる正極集電体の両面に均一に塗布して乾燥し、その後、ローラプレス機により圧縮成形した後、切断し、リード体を溶接して作製した。次ぎに負極は、平均粒径10μmの炭素材料を、フッ化ビニリデンをN‐メチルピロリドンに溶解させた溶液と混合してスラリーにした。この負極合剤スラリーを70メッシュの網を通過させて大きなものを取り除いた後、厚さ18μmの帯状の銅箔からなる負極集電体の両面に均一に塗布して乾燥し、その後ローラプレス機により圧縮成形し切断して作製した。 After taking out from the dryer and cooling, the porous film was taken out and used as a sample for a needle-inserted probe thermomechanical analyzer. The positive electrode used was lithium cobalt oxide (LiClO 2 ) mixed with phosphorous graphite as a conductive additive at a weight ratio of 90: 5, and this mixture and polyvinylidene fluoride were dissolved in N-methylpyrrolidone. The solution was mixed into a slurry. This positive electrode mixture slurry was passed through a 70 mesh net to remove a large one, and then uniformly applied to both sides of a positive electrode current collector made of an aluminum foil having a thickness of 20 μm and dried. After compression molding, it was cut and produced by welding the lead body. Next, the negative electrode was made into a slurry by mixing a carbon material having an average particle diameter of 10 μm with a solution in which vinylidene fluoride was dissolved in N-methylpyrrolidone. This negative electrode mixture slurry was passed through a 70 mesh net to remove a large one, and then uniformly applied to both sides of a negative electrode current collector made of a strip-shaped copper foil having a thickness of 18 μm and dried, and then a roller press machine And compression molded and cut.
針入プローブ式熱機械的分析装置(セイコー電子製EXSTAR6000)を用いて、幅5mm角のサンプル片に先端1mmφの針入プローブを乗せ、プローブ上に70gfの荷重をかけたときの厚みの変化を昇温2℃/minで計測した。計測後のデータから荷重後を原点、昇温により燃焼して平坦となった点を終点として180℃での膜の厚み維持率を読みとった。 Using a needle-inserted probe type thermomechanical analyzer (EXSTAR6000 manufactured by Seiko Denshi), the thickness change when a 70 gf load was applied to the probe with a 1 mmφ tip placed on a 5 mm square sample piece. Measurement was performed at a temperature rise of 2 ° C./min. From the measured data, the film thickness retention rate at 180 ° C. was read from the origin after loading and the point at which the fuel burned and flattened as the temperature rose.
厚み維持率(%)=100×(終点の厚み−180℃厚み)/(終点の厚み−70gf荷重後の厚み)
厚み維持率(%)は上記の式で計算される値である。
Thickness maintenance ratio (%) = 100 × (end point thickness−180 ° C. thickness) / (end point thickness−thickness after 70 gf load)
The thickness maintenance ratio (%) is a value calculated by the above formula.
[調製例1]
重量平均分子量150万の超高分子量ポリエチレン60重量%、無水マレイン酸グラフト高密度ポリエチレン(日本ポリオレフィン製アドテックスER403A )30重量%、EPDM(エチリデンノルボルネン含量4.5重量%,住友化学製エスプレン553)10重量%からなる樹脂組成物15重量部と流動パラフィン85重量部とを用いて、最終工程で得られた多孔質フィルムを空気中にて85℃で2時間熱処理し、ついで122℃で2時間熱処理した以外は実施例1と同様に製膜を行い、多孔質フィルムを得た。この多孔質フィルムはIRとゲル分率との測定から架橋構造が確認され、厚み15μm、空孔率38%、通気度260秒/100cc、収縮率21%、針突き刺し強度2.3N、シャットダウン温度132℃であった。
[Preparation Example 1]
60% by weight of ultra high molecular weight polyethylene with a weight average molecular weight of 1,500,000, maleic anhydride grafted high density polyethylene (Adtex ER403A, manufactured by Nippon Polyolefin), 30% by weight, EPDM (ethylidene norbornene content: 4.5% by weight, Esprene 553, manufactured by Sumitomo Chemical) The porous film obtained in the final step was heat-treated in air at 85 ° C. for 2 hours using 15% by weight of a resin composition consisting of 10% by weight and 85 parts by weight of liquid paraffin, and then at 122 ° C. for 2 hours. Except for the heat treatment, a film was formed in the same manner as in Example 1 to obtain a porous film. This porous film was confirmed to have a crosslinked structure from IR and gel fraction measurements. The thickness was 15 μm, the porosity was 38%, the air permeability was 260 seconds / 100 cc, the shrinkage was 21%, the needle penetration strength was 2.3 N, and the shutdown temperature. It was 132 ° C.
[調製例2]
重量平均分子量150万の超高分子量ポリエチレン(ヘキスト製GUR4012)61重量%、無水マレイン酸グラフト高密度ポリエチレン(日本ポリオレフィン製アドテックスER403A )31重量%、ポリノルボルネン(日本ゼオン製Norsorex)8重量%からなる樹脂組成物15重量部と流動パラフィン85重量部とをスラリー状に均一に混合し、160℃の温度で小型ニーダーを用い約60分溶解混練りした。その後これらの混練物を0℃に冷却されたロールまたは金属板に挟み込みシート状に急冷した。これらの急冷シート状樹脂を、115℃の温度でシート厚0.4mmになるまでヒートプレスし、123℃の温度で同時に縦横4×4倍に二軸延伸し、ヘプタンを使用して脱溶媒処理を行った。その後、得られた多孔質フィルムを空気中にて85℃で2時間熱処理し、ついで122℃で2時間熱処理して、多孔質フィルムを得た。この多孔質フィルムはIRとゲル分率との測定から架橋構造が確認され、厚み17μm、空孔率51%、通気度200秒/100cc、収縮率24%、針突き刺し強度2.0N、シャットダウン温度133℃であった。
[Preparation Example 2]
From 61% by weight of ultrahigh molecular weight polyethylene (GUR4012 manufactured by Hoechst) having a weight average molecular weight of 1.5 million, 31% by weight of maleic anhydride grafted high density polyethylene (Adtex ER403A manufactured by Nippon Polyolefin), and 8% by weight of polynorbornene (Norsolex manufactured by Nippon Zeon) 15 parts by weight of the resulting resin composition and 85 parts by weight of liquid paraffin were uniformly mixed in a slurry form, and dissolved and kneaded at a temperature of 160 ° C. using a small kneader for about 60 minutes. Thereafter, these kneaded materials were sandwiched between rolls or metal plates cooled to 0 ° C. and rapidly cooled into a sheet shape. These quenched resin sheets are heat-pressed at a temperature of 115 ° C. until the sheet thickness reaches 0.4 mm, and simultaneously biaxially stretched 4 × 4 times in length and width at a temperature of 123 ° C., and solvent-removed using heptane. Went. Thereafter, the obtained porous film was heat-treated in air at 85 ° C. for 2 hours, and then heat-treated at 122 ° C. for 2 hours to obtain a porous film. This porous film was confirmed to have a crosslinked structure from the measurement of IR and gel fraction, thickness 17 μm, porosity 51%, air permeability 200 seconds / 100 cc, shrinkage 24%, needle penetration strength 2.0 N, shutdown temperature It was 133 ° C.
[調整例3]
重量平均分子量20万のポリエチレン60重量%、重量平均分子量150万の超高分子量ポリエチレン40重量%からなる樹脂組成物15重量部と流動パラフィン85重量部とを用いて、最終工程で得られた多孔質フィルムを空気中にて85℃で2時間熱処理し、ついで120℃で2時間熱処理した以外は実施例1と同様に製膜を行い、多孔質フィルムを得た。この多孔質フィルムは厚み17μm、空孔率36%、通気度320秒/100cc、収縮率30%、針突き刺し強度2.0N、シャットダウン温度133℃であった。
[Adjustment Example 3]
A porous material obtained in the final step using 15 parts by weight of a resin composition comprising 60% by weight of polyethylene having a weight average molecular weight of 200,000 and 40% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,500,000 and 85 parts by weight of liquid paraffin. A porous film was obtained in the same manner as in Example 1 except that the porous film was heat-treated in air at 85 ° C. for 2 hours and then heat-treated at 120 ° C. for 2 hours. This porous film had a thickness of 17 μm, a porosity of 36%, an air permeability of 320 seconds / 100 cc, a shrinkage rate of 30%, a needle penetration strength of 2.0 N, and a shutdown temperature of 133 ° C.
[調製例4]
重量平均分子量20万のポリエチレン54重量%、重量平均分子量150万の超高分子量ポリエチレン36重量%、EPDM(エチリデンノルボルネン含量4.5重量%,住友化学製エスプレン553)10重量%からなる樹脂組成物15重量部と流動パラフィン85重量部とを用いて、最終工程で得られた多孔質フィルムを空気中にて85℃で2時間熱処理し、ついで120℃で2時間熱処理した以外は実施例1と同様に製膜を行い、多孔質フィルムを得た。この多孔質フィルムはIRとゲル分率との測定から架橋構造が確認され、厚み16μm、空孔率33%、通気度550秒/100cc、収縮率28%、針突き刺し強度2.1N、シャットダウン温度133℃であった。
[Preparation Example 4]
Resin composition comprising 54% by weight of polyethylene having a weight average molecular weight of 200,000, 36% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,500,000, and 10% by weight of EPDM (ethylidene norbornene content: 4.5% by weight, Esprene 553 manufactured by Sumitomo Chemical) Example 1 except that the porous film obtained in the final step was heat-treated at 85 ° C. for 2 hours in air and then heat-treated at 120 ° C. for 2 hours using 15 parts by weight and 85 parts by weight of liquid paraffin. Film formation was performed in the same manner to obtain a porous film. This porous film was confirmed to have a crosslinked structure from IR and gel fraction measurements. The thickness was 16 μm, the porosity was 33%, the air permeability was 550 seconds / 100 cc, the shrinkage was 28%, the needle penetration strength was 2.1 N, and the shutdown temperature. It was 133 ° C.
[実施例1]
調製例1で得られた多孔質フィルムを用い、耐熱試験後のフィルム状態を観察したところ、端部の収縮や電極を覆っている表面の破膜は起こっていなかった。また、耐熱試験後の試料を取り出して針侵入式熱機械的分析装置により70gf荷重後厚み、燃焼による終点厚み、180℃に到達したときの厚みを測定し、フィルムの厚み維持率を求めた。
[Example 1]
When the film state after the heat resistance test was observed using the porous film obtained in Preparation Example 1, no shrinkage of the end portion or film breakage of the surface covering the electrode occurred. Further, a sample after the heat resistance test was taken out, and the thickness after 70 gf load, the end point thickness due to combustion, and the thickness when reaching 180 ° C. were measured by a needle penetration type thermomechanical analyzer, and the thickness maintenance rate of the film was determined.
[実施例2]
調製例2で得られた多孔質フィルムを用い、耐熱試験後のフィルム状態を観察したところ、端部の収縮や電極を覆っている表面の破膜は起こっていなかった。また、耐熱試験後の試料を取り出して針侵入式熱機械的分析装置により70gf荷重後厚み、燃焼による終点厚み、180℃に到達したときの厚みを測定し、フィルムの厚み維持率を求めた。
[Example 2]
Using the porous film obtained in Preparation Example 2 and observing the film state after the heat resistance test, no shrinkage of the end portions or film breakage of the surface covering the electrodes occurred. Further, a sample after the heat resistance test was taken out, and the thickness after 70 gf load, the end point thickness due to combustion, and the thickness when reaching 180 ° C. were measured by a needle penetration type thermomechanical analyzer, and the thickness maintenance rate of the film was determined.
[比較例1]
調製例3で得られた多孔質フィルムを用い、耐熱試験後のフィルム状態を観察したところ、端部の収縮は起こっていないが、電極を覆っている表面に破膜による小さな穴が観察された。また、耐熱試験後の試料を取り出して針侵入式熱機械的分析装置により70gf荷重後厚み、燃焼による終点厚み、180℃に到達したときの厚みを測定し、フィルムの厚み維持率を求めた。
[Comparative Example 1]
When the film state after the heat resistance test was observed using the porous film obtained in Preparation Example 3, no shrinkage of the end portion occurred, but a small hole due to a membrane breakage was observed on the surface covering the electrode. . Further, a sample after the heat resistance test was taken out, and the thickness after 70 gf load, the end point thickness due to combustion, and the thickness when reaching 180 ° C. were measured by a needle penetration type thermomechanical analyzer, and the thickness maintenance rate of the film was determined.
[比較例2]
調製例4で得られた多孔質フィルムを用い、耐熱試験後のフィルム状態を観察したところ、端部の収縮が観察されて、電極面が一部露出していた。また、耐熱試験後の試料を取り出して針侵入式熱機械的分析装置により70gf荷重後厚み、燃焼による終点厚み、180℃に到達したときの厚みを測定し、フィルムの厚み維持率を求めた。
[Comparative Example 2]
When the film state after the heat resistance test was observed using the porous film obtained in Preparation Example 4, shrinkage of the edge was observed, and a part of the electrode surface was exposed. Further, a sample after the heat resistance test was taken out, and the thickness after 70 gf load, the end point thickness due to combustion, and the thickness when reaching 180 ° C. were measured by a needle penetration type thermomechanical analyzer, and the thickness maintenance rate of the film was determined.
実施例、比較例で得られた多孔質フィルムの特性を表1に示す。 Table 1 shows the characteristics of the porous films obtained in Examples and Comparative Examples.
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Cited By (4)
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JP2007080558A (en) * | 2005-09-12 | 2007-03-29 | Nitto Denko Corp | Electrolyte membrane and polymer electrolyte fuel cell |
JP2009117230A (en) * | 2007-11-08 | 2009-05-28 | Fujitsu Ltd | Measuring method for separator of secondary battery |
JP2010244874A (en) * | 2009-04-07 | 2010-10-28 | Panasonic Corp | Lithium ion secondary battery |
US20160082397A1 (en) * | 2013-05-07 | 2016-03-24 | Teijin Limited | Substrate for liquid filter |
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Cited By (5)
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JP2007080558A (en) * | 2005-09-12 | 2007-03-29 | Nitto Denko Corp | Electrolyte membrane and polymer electrolyte fuel cell |
JP2009117230A (en) * | 2007-11-08 | 2009-05-28 | Fujitsu Ltd | Measuring method for separator of secondary battery |
JP2010244874A (en) * | 2009-04-07 | 2010-10-28 | Panasonic Corp | Lithium ion secondary battery |
US20160082397A1 (en) * | 2013-05-07 | 2016-03-24 | Teijin Limited | Substrate for liquid filter |
US11338251B2 (en) * | 2013-05-07 | 2022-05-24 | Teijin Limited | Substrate for liquid filter |
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