JP2013114825A - Electrode laminate and lithium ion secondary battery using the same - Google Patents
Electrode laminate and lithium ion secondary battery using the same Download PDFInfo
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リチウムイオン二次電池は一般に、正極、負極の電極同士がセパレータを介して交互に層状に積層された「電極積層体」を有する。本発明は、帯状の正極部材と負極部材が帯状のセパレータとともに重ね合わされて巻き回されたタイプの電極積層体、およびそれを用いたリチウムイオン二次電池に関する。 Generally, a lithium ion secondary battery has an “electrode stack” in which positive and negative electrodes are alternately stacked in layers via separators. The present invention relates to an electrode laminate in which a belt-like positive electrode member and a negative electrode member are overlapped and wound together with a belt-like separator, and a lithium ion secondary battery using the same.
本明細書において、「電極」とは集電体として機能する金属薄板の表面にリチウムイオン二次電池用の正極活物質あるいは負極活物質が担持された状態の板状体をいう。電極を構成する上記の金属薄板の部分を「集電体」と呼ぶ。電極のうち正極活物質を有するものを「正極」、負極活物質を有するものを「負極」と呼ぶ。「箔」とは厚さが１００μｍ以下の薄板を意味する。上記の各帯状部材が巻き回されたタイプの電極積層体を「巻回し型電極積層体」と呼ぶ。 In the present specification, the “electrode” refers to a plate-like body in which a positive electrode active material or a negative electrode active material for a lithium ion secondary battery is supported on the surface of a thin metal plate that functions as a current collector. The portion of the thin metal plate that constitutes the electrode is referred to as a “current collector”. Of the electrodes, one having a positive electrode active material is called a “positive electrode”, and one having a negative electrode active material is called a “negative electrode”. “Foil” means a thin plate having a thickness of 100 μm or less. A type of electrode laminate in which each of the belt-like members is wound is referred to as a “rolled electrode laminate”.
リチウムイオン二次電池の巻回し型電極積層体の製造方法としては、通常、第１の帯状金属箔の表面に正極活物質を担持した帯状正極部材と、第２の帯状金属箔の表面に負極活物質を担持した帯状負極部材を、帯状セパレータとともに重ね合せて、巻取りリールによって巻き取る手法が採用される（例えば特許文献１参照）。巻取りリールで巻き取られる各帯状部材（具体的には、帯状正極部材、帯状負極部材および帯状セパレータ）は、それぞれ独立した送給装置によって連続的に供給され、所定の積層順序に重ね合わされた状態で巻き回される。巻き回されて得られた電極積層体において各部材が密着するように、それぞれの帯状部材は所定の張力が付与された状態で巻き回される。その巻き回し時の張力は通常、帯状部材の送給経路に設けられたリールを用いて各帯状部材ごとに調整される。 As a method for producing a wound electrode laminate of a lithium ion secondary battery, a strip-like positive electrode member carrying a cathode active material on the surface of a first strip metal foil and a negative electrode on the surface of a second strip metal foil are usually used. A technique is adopted in which a strip-shaped negative electrode member carrying an active material is overlapped with a strip-shaped separator and wound by a take-up reel (for example, see Patent Document 1). Each belt-like member (specifically, the belt-like positive electrode member, the belt-like negative electrode member, and the belt-like separator) taken up by the take-up reel is continuously supplied by an independent feeding device, and overlapped in a predetermined stacking order. It is wound in the state. In the electrode laminate obtained by winding, each belt-like member is wound in a state where a predetermined tension is applied so that the respective members are in close contact with each other. The tension at the time of winding is usually adjusted for each belt-like member using a reel provided in the feeding path of the belt-like member.
各部材の巻き回し時の張力が小さすぎると、巻き回されて得られた電極積層体において巻きズレが生じやすくなる。また、電池の充放電に伴う活物質層の体積変化に起因して巻き緩みが生じやすくなる。そこで、巻回し型電極積層体の巻き回し時に一定以上の張力を確保する手法が提案されている（特許文献２、３）。
If the tension at the time of winding of each member is too small, winding misalignment is likely to occur in the electrode laminate obtained by winding. In addition, loose winding is likely to occur due to the volume change of the active material layer accompanying charging / discharging of the battery. In view of this, there has been proposed a technique for ensuring a certain level of tension when the wound electrode laminate is wound (
従来一般的に、リチウムイオン二次電池の電極を構成する集電体としては、正極にアルミニウム箔、負極に銅箔が使用されている。これらの金属箔は強度が低いので、巻回し型電極積層体を作製する際、巻き回し時に付与される張力によって金属箔が変形しやすい。金属箔の変形が大きいと、その表面に存在する活物質層の一部が金属箔から剥離する現象が生じ、これが活物質層／集電体間の界面抵抗を増大させ、出力特性・寿命特性などの電池性能の低下を招く要因となる。また、低強度の金属箔を用いた場合には巻き回し時に金属箔の破断が生じないように張力を低く設定する必要がある。このため充放電サイクルを繰り返すと活物質層の膨張・収縮に起因して集電体が動きやすく、電極積層体には巻き緩みや活物質層の密着性低下が生じやすい。巻き緩みは電極間距離を増大させ、活物質層の密着性低下は活物質層／集電体間の界面抵抗を増大させる。これらは電池容量を低下させる要因となる。 Conventionally, as a current collector constituting an electrode of a lithium ion secondary battery, an aluminum foil is used for a positive electrode and a copper foil is used for a negative electrode. Since these metal foils have low strength, the metal foil is likely to be deformed by the tension applied during winding when producing a wound electrode laminate. If the deformation of the metal foil is large, a part of the active material layer existing on the surface peels off from the metal foil, which increases the interface resistance between the active material layer / current collector, and the output characteristics and life characteristics. This causes a decrease in battery performance. Further, when a low-strength metal foil is used, it is necessary to set the tension low so that the metal foil does not break during winding. For this reason, when the charge / discharge cycle is repeated, the current collector tends to move due to the expansion / contraction of the active material layer, and the electrode laminate tends to loosen the winding or deteriorate the adhesion of the active material layer. Loosening increases the distance between the electrodes, and lowering the adhesion of the active material layer increases the interface resistance between the active material layer / current collector. These are factors that reduce the battery capacity.
本発明は、上記のような従来のリチウムイオン二次電池の巻回し型電極積層体に特有の電池性能低下の問題を改善することを目的とする。 An object of the present invention is to ameliorate the problem of deterioration in battery performance peculiar to the above-described conventional wound electrode laminate of a lithium ion secondary battery.
発明者らは詳細な検討の結果、リチウムイオン二次電池の電極材料として鋼をベースとした金属箔が適用可能であることを確認した。具体的には正極集電体としてステンレス鋼箔が適用可能であり、負極集電体としてステンレス鋼箔および銅被覆鋼箔が適用可能であることがわかった。上記目的はこのような鋼をベースとした金属箔を集電体に用いることによって実現可能となる。 As a result of detailed studies, the inventors have confirmed that a metal foil based on steel is applicable as an electrode material of a lithium ion secondary battery. Specifically, it was found that stainless steel foil can be applied as the positive electrode current collector, and stainless steel foil and copper-coated steel foil can be applied as the negative electrode current collector. The above object can be realized by using such a steel-based metal foil as a current collector.
すなわち本発明では、第１の帯状金属箔の表面に正極活物質を担持した帯状正極部材と、第２の帯状金属箔の表面に負極活物質を担持した帯状負極部材が、帯状セパレータとともに重ね合わされて巻き回された構造を有するリチウムイオン二次電池の電極積層体であって、
第１および第２の帯状金属箔の少なくとも一方に引張強さが４５０〜９００ＭＰａの金属箔を適用したリチウムイオン二次電池の電極積層体が提供される。
That is, in the present invention, the belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil are superposed together with the belt-like separator. An electrode laminate of a lithium ion secondary battery having a wound structure,
An electrode laminate for a lithium ion secondary battery is provided in which a metal foil having a tensile strength of 450 to 900 MPa is applied to at least one of the first and second strip metal foils.
第１の帯状金属箔と第２の帯状金属箔の具体的な組合わせとしては、以下のものが挙げられる。
（１）第１の帯状金属箔がアルミニウム箔、第２の帯状金属箔が引張強さ４５０〜９００ＭＰａの銅被覆鋼箔であるもの。
（２）第１の帯状金属箔がアルミニウム箔、第２の帯状金属箔が引張強さ４５０〜９００ＭＰａかつＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔であるもの。
（３）第１の帯状金属箔が引張強さ４５０〜９００ＭＰａのステンレス鋼箔、第２の帯状金属箔が銅箔であるもの。
（４）第１の帯状金属箔がＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔、第２の帯状金属箔が銅被覆鋼箔であり、前記第１および第２の帯状金属箔のうち少なくとも一方が引張強さ４５０〜９００ＭＰａの金属箔であるであるもの。
（５）第１の帯状金属箔および第２の帯状金属箔がそれぞれＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔であり、前記第１および第２の帯状金属箔のうち少なくとも一方が引張強さ４５０〜９００ＭＰａの金属箔であるもの。
Specific combinations of the first strip-shaped metal foil and the second strip-shaped metal foil include the following.
(1) The first strip metal foil is an aluminum foil, and the second strip metal foil is a copper-coated steel foil having a tensile strength of 450 to 900 MPa.
(2) The first strip metal foil is an aluminum foil, and the second strip metal foil is a stainless steel foil having a tensile strength of 450 to 900 MPa and a Cr content of 10.5 to 30.5 mass%.
(3) The first strip metal foil is a stainless steel foil having a tensile strength of 450 to 900 MPa, and the second strip metal foil is a copper foil.
(4) The first strip metal foil is a stainless steel foil having a Cr content of 10.5 to 30.5 mass%, the second strip metal foil is a copper-coated steel foil, and the first and second strip metals At least one of the foils is a metal foil having a tensile strength of 450 to 900 MPa.
(5) The first strip-shaped metal foil and the second strip-shaped metal foil are stainless steel foils each having a Cr content of 10.5 to 30.5% by mass, and at least of the first and second strip-shaped metal foils One is a metal foil having a tensile strength of 450 to 900 MPa.
上記それぞれの電極積層体は、前記引張強さ４５０〜９００ＭＰａの帯状金属箔（ただし、上記（４）（５）の場合には引張強さ４５０〜９００ＭＰａの帯状金属箔のうち少なくとも１つ）に４００ＭＰａ以上かつ当該帯状金属箔の引張強さの９０％以下の張力が付与された状態で巻き回されたものであることが、より好ましい。 Each of the electrode laminates is a strip-shaped metal foil having a tensile strength of 450 to 900 MPa (however, in the case of the above (4) and (5), at least one of the strip-shaped metal foils having a tensile strength of 450 to 900 MPa). More preferably, it is wound in a state where a tension of 400 MPa or more and 90% or less of the tensile strength of the strip-shaped metal foil is applied.
また本発明では、上記（１）〜（５）のいずれかの電極積層体を用いたリチウムイオン二次電池が提供される。 Moreover, in this invention, the lithium ion secondary battery using the electrode laminated body in any one of said (1)-(5) is provided.
本発明によれば、リチウムイオン二次電池の巻回し型電極積層体に高強度な金属箔からなる集電体を適用するので、その金属箔を用いた電極においては巻き回し時の金属箔の弾性変形が小さいため活物質層の密着性が高く維持される。また、巻き回し時に上記高強度な金属箔の張力を高めることで、電極積層体には強い締め付け力を付与することができる。そのため、充放電の繰り返しによっても巻き緩みや活物質層の剥離が生じにくく、良好な電池性能がより長期にわたって維持される。したがって本発明は巻回し型電極積層体を用いたリチウムイオン二次電池の性能向上に寄与するものである。 According to the present invention, the current collector made of a high-strength metal foil is applied to the wound electrode laminate of the lithium ion secondary battery. Therefore, in the electrode using the metal foil, the metal foil at the time of winding is used. Since the elastic deformation is small, the adhesion of the active material layer is maintained high. Moreover, a strong clamping force can be applied to the electrode laminate by increasing the tension of the high-strength metal foil during winding. Therefore, loose winding and peeling of the active material layer are less likely to occur due to repeated charge and discharge, and good battery performance is maintained for a longer period. Therefore, this invention contributes to the performance improvement of the lithium ion secondary battery using a winding type electrode laminated body.
本発明では第１の帯状金属箔の表面に正極活物質を担持した帯状正極部材と、第２の帯状金属箔の表面に負極活物質を担持した帯状負極部材が、帯状セパレータとともに重ね合わされて巻き回された構造を有するリチウムイオン二次電池の電極積層体、すなわち巻回し型電極積層体を対象とする。各構成部材の積層順序や、セパレータの種類、電池ケースに収納された使用形態については従来一般的な例に従うことができる。しかし、本発明の電極積層体は上記第１、第２の帯状金属箔の少なくとも一方に高強度な材料を使用する点で従来のものと構造を異にする。 In the present invention, the belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil are overlapped together with the belt-like separator and wound. The object is an electrode laminate of a lithium ion secondary battery having a rotated structure, that is, a wound electrode laminate. Conventionally general examples can be followed for the stacking order of the constituent members, the type of separator, and the usage pattern stored in the battery case. However, the electrode laminate of the present invention differs in structure from the conventional one in that a high-strength material is used for at least one of the first and second strip metal foils.
〔帯状金属箔の引張強さ〕
本発明に従うリチウムイオン二次電池の電極積層体においては、正極、負極の少なくとも一方の集電体に、引張強さが４５０〜９００ＭＰａと高い帯状金属箔を適用する。ここで、引張強さは帯の長手方向に測定した値が採用される。
[Tensile strength of strip metal foil]
In the electrode laminate of the lithium ion secondary battery according to the present invention, a strip metal foil having a high tensile strength of 450 to 900 MPa is applied to at least one of the positive electrode and negative electrode current collectors. Here, the value measured in the longitudinal direction of the strip is adopted as the tensile strength.
引張強さが高い金属箔は一般に剛性も高いので、巻き回し時の張力による弾性変形が抑制される。弾性変形が小さいと、金属箔と、その金属箔の表面に付着している活物質層との界面に働くせん断力が小さくなるので、活物質層が部分的に金属箔から剥離する現象が抑えられ、従来よりも良好な活物質密着性を有する状態で巻き取ることができる。この密着性の向上は界面抵抗の低下に寄与し、電池性能の向上につながる。引張強さが従来のアルミニウム箔や銅箔よりも大幅に高い金属箔を適用すれば、巻き回し時の張力を従来より高めた場合でも、弾性変形を従来より抑制することが可能となる。 A metal foil having a high tensile strength generally has a high rigidity, so that elastic deformation due to a tension during winding is suppressed. If the elastic deformation is small, the shear force acting on the interface between the metal foil and the active material layer adhering to the surface of the metal foil is reduced, so that the phenomenon that the active material layer is partially detached from the metal foil is suppressed. And can be wound in a state having better active material adhesion than before. This improvement in adhesion contributes to a decrease in interfacial resistance and leads to an improvement in battery performance. If a metal foil having a tensile strength significantly higher than that of a conventional aluminum foil or copper foil is applied, even when the tension at the time of winding is increased as compared with the conventional case, elastic deformation can be suppressed as compared with the conventional case.
また、巻き回しに供する正極用および負極用の帯状金属箔のうち、少なくともいずれか一方の帯状金属箔を引張強さの高いものとすれば、その帯状金属箔には巻き回し時に高い張力を付与することができる。その高い張力によって、巻き終えて完成した巻回し型電極積層体には強い締め付け力が付与され、巻き緩みや巻きズレに対する抵抗力が増大する。リチウムイオン二次電池は充放電時に活物質層の体積変動を伴う。充放電を繰り返す過程で活物質層の膨張によって巻き緩みが生じると、結果的に巻回し型電極積層体における平均電極間距離が増大する。また、充放電に伴う巻き緩みや巻きズレの発生は金属箔（集電体）から活物質層が部分的に剥離する現象を招く要因となる。したがって、強い締め付け力が付与された巻回し型電極積層体は巻き緩みや巻きズレに伴う電池性能の低下を引き起こしにくい。 In addition, if at least one of the strip-like metal foils for the positive electrode and the negative electrode used for winding has a high tensile strength, the strip-shaped metal foil is given high tension when wound. can do. Due to the high tension, a strong clamping force is imparted to the wound electrode laminate that has been wound and completed, and the resistance to winding looseness and winding deviation increases. Lithium ion secondary batteries are accompanied by volume fluctuations of the active material layer during charging and discharging. If loosening occurs due to the expansion of the active material layer in the process of repeated charge and discharge, the average inter-electrode distance in the wound electrode laminate increases as a result. In addition, the loosening of the winding and the occurrence of winding misalignment associated with charging / discharging cause a phenomenon that the active material layer is partially separated from the metal foil (current collector). Therefore, the wound electrode laminate to which a strong tightening force is applied is unlikely to cause a decrease in battery performance due to loosening or misalignment.
さらに、引張強さが高い金属箔を使用すると、活物質層を形成する際のロールプレスにおいて高い圧下力を付与しても箔の塑性変形（中伸び）が生じにくい。ロールプレスでの圧下力を高めると活物質層の密度を高めることができるので、電極の体積当たりの充放電容量を増大させることができる。 Furthermore, when a metal foil having a high tensile strength is used, even when a high rolling force is applied in the roll press when forming the active material layer, the plastic deformation (medium elongation) of the foil hardly occurs. Since the density of the active material layer can be increased by increasing the rolling force in the roll press, the charge / discharge capacity per volume of the electrode can be increased.
種々検討の結果、上述の弾性変形を低減したり、張力を増大させて巻き緩みや巻きズレに対する抵抗力が増大させるためには、正極、負極の少なくとも一方の集電体に、引張強さ４５０ＭＰａ以上の帯状金属箔を適用することが極めて有効である。５００ＭＰａ以上、あるいは６００ＭＰａ以上の帯状金属箔を適用することが一層好ましい。 As a result of various studies, in order to reduce the above-described elastic deformation or increase the tension to increase the resistance to winding looseness or winding displacement, a tensile strength of 450 MPa is applied to at least one of the positive electrode and negative electrode current collectors. It is extremely effective to apply the above-described strip metal foil. It is more preferable to apply a strip metal foil of 500 MPa or more, or 600 MPa or more.
一方、引張強さが過剰に高い帯状金属箔を生産することはコスト増を招き好ましくない。また、一般に高強度材料は弾性変形領域が少なく耐折れ性に劣るため、過度に高強度化すると取扱いが困難となる。種々検討の結果、帯状金属箔の引張強さは９００ＭＰａ以下とすればよい。 On the other hand, it is not preferable to produce a strip-shaped metal foil having an excessively high tensile strength due to an increase in cost. In general, a high-strength material has a small elastic deformation region and is inferior in folding resistance. As a result of various studies, the tensile strength of the strip-shaped metal foil may be 900 MPa or less.
〔適用可能な帯状金属箔〕
リチウムイオン二次電池の集電体となる帯状金属箔として、正極には従来一般的なアルミニウム箔の他、ステンレス鋼箔が適用可能であることがわかった。また負極には従来一般的な銅箔の他、ステンレス鋼箔および銅被覆鋼箔が適用可能であることがわかった。これらの帯状金属箔の厚さは３〜１００μｍの範囲で設定すればよい。上記のうちステンレス鋼箔および銅被覆鋼箔において引張強さ４５０〜９００ＭＰａを実現することができる。以下にステンレス鋼箔および銅被覆鋼箔について説明する。
[Applicable strip metal foil]
As a strip-like metal foil serving as a current collector of a lithium ion secondary battery, it has been found that a stainless steel foil can be applied to the positive electrode in addition to a conventional aluminum foil. Moreover, it turned out that stainless steel foil and copper-coated steel foil can be applied to the negative electrode in addition to conventional copper foil. What is necessary is just to set the thickness of these strip | belt-shaped metal foils in the range of 3-100 micrometers. Among the above, a tensile strength of 450 to 900 MPa can be realized in the stainless steel foil and the copper-coated steel foil. The stainless steel foil and the copper-coated steel foil will be described below.
〔ステンレス鋼箔〕
ステンレス鋼とは、ＪＩＳ Ｇ０２０３：２００９の番号３８０１に示されているように、Ｃｒ含有量１０.５質量％以上、Ｃ含有量１.２質量％以下として耐食性を向上させた合金鋼である。ただし、リチウムイオン二次電池の電解液中で正極または負極の集電体として長期間使用するためにはある程度高い耐食性を有する鋼種を採用することが有利となる。発明者らの検討によれば、Ｃｒ含有量が１０.５質量％以上のオーステナイト系またはフェライト系ステンレス鋼が適用することが好ましい。ただし、Ｃｒ含有量が過度に高くなると加工性が低下し、箔のコスト増を招くので、Ｃｒ含有量は要求される耐食性レベルに応じて３０.５質量％以下の範囲で設定すればよい。製造性およびコストの面からは、Ｃｒ含有量は２６.０質量％以下とすることがより好ましく、２０.０質量％以下が一層好ましい。
具体的な成分組成範囲は以下のものが例示できる。
[Stainless steel foil]
Stainless steel is an alloy steel having improved corrosion resistance with a Cr content of 10.5 mass% or more and a C content of 1.2 mass% or less, as shown in JIS G0203: 2009, number 3801. However, it is advantageous to employ a steel type having a certain degree of corrosion resistance in order to use it as a positive electrode or negative electrode current collector for a long time in the electrolyte solution of a lithium ion secondary battery. According to the study by the inventors, it is preferable to apply an austenitic or ferritic stainless steel having a Cr content of 10.5% by mass or more. However, if the Cr content is excessively high, the workability is lowered and the cost of the foil is increased. Therefore, the Cr content may be set in a range of 30.5 mass% or less depending on the required corrosion resistance level. From the viewpoint of manufacturability and cost, the Cr content is more preferably 26.0% by mass or less, and further preferably 20.0% by mass or less.
Specific component composition ranges can be exemplified as follows.
オーステナイト系ステンレス鋼種；
質量％で、Ｃ：０.０００１〜０.１５％、Ｓｉ：０.００１〜４.０％、Ｍｎ：０.００１〜２.５％、Ｐ：０.００１〜０.０４５％、Ｓ：０.０００５〜０.０３％、Ｎｉ：６.０〜２８.０％、Ｃｒ：１０.５〜３０.５％、Ｍｏ：０〜７.０％、Ｃｕ：０〜３.５％、Ｎｂ：０〜１.０％、Ｔｉ：０〜１.０％、Ａｌ：０〜０.１％、Ｎ：０〜０.３％、Ｂ：０〜０.０１％、Ｖ：０〜０.５％、Ｗ：０〜０.３％、Ｃａ、Ｍｇ、Ｙ、ＲＥＭ（希土類元素）の合計：０〜０.１％、残部Ｆｅおよび不可避的不純物。
Austenitic stainless steel grades;
By mass%, C: 0.0001 to 0.15%, Si: 0.001 to 4.0%, Mn: 0.001 to 2.5%, P: 0.001 to 0.045%, S: 0.0005 to 0.03%, Ni: 6.0 to 28.0%, Cr: 10.5 to 30.5%, Mo: 0 to 7.0%, Cu: 0 to 3.5%, Nb : 0-1.0%, Ti: 0-1.0%, Al: 0-0.1%, N: 0-0.3%, B: 0-0.01%, V: 0-0. 5%, W: 0 to 0.3%, Ca, Mg, Y, REM (rare earth elements) total: 0 to 0.1%, balance Fe and inevitable impurities.
フェライト系ステンレス鋼鋼種；
質量％で、Ｃ：０.０００１〜０.１５％、Ｓｉ：０.００１〜１.２％、Ｍｎ：０.００１〜１.２％、Ｐ：０.００１〜０.０４％、Ｓ：０.０００５〜０.０３％、Ｎｉ：０〜０.６％、Ｃｒ：１０.５〜３０.５％、Ｍｏ：０〜２.５％、Ｃｕ：０〜１.０％、Ｎｂ：０〜１.０％、Ｔｉ：０〜１.０％、Ａｌ：０〜５.０％、Ｎ：０〜０.０２５％、Ｂ：０〜０.０１％、Ｖ：０〜０.５％、Ｗ：０〜０.３％、Ｃａ、Ｍｇ、Ｙ、ＲＥＭ（希土類元素）の合計：０〜０.１％、残部Ｆｅおよび不可避的不純物。
Ferritic stainless steel grades;
By mass%, C: 0.0001 to 0.15%, Si: 0.001 to 1.2%, Mn: 0.001 to 1.2%, P: 0.001 to 0.04%, S: 0.0005 to 0.03%, Ni: 0 to 0.6%, Cr: 10.5 to 30.5%, Mo: 0 to 2.5%, Cu: 0 to 1.0%, Nb: 0 ~ 1.0%, Ti: 0 to 1.0%, Al: 0 to 5.0%, N: 0 to 0.025%, B: 0 to 0.01%, V: 0 to 0.5% , W: 0 to 0.3%, Ca, Mg, Y, REM (rare earth elements) total: 0 to 0.1%, remaining Fe and inevitable impurities.
規格鋼種の中では、例えばＪＩＳ Ｇ４３０５：２００５に規定されるオーステナイト系またはフェライト系の化学組成を有する鋼種を適用することができる。 Among standard steel types, for example, a steel type having an austenitic or ferritic chemical composition defined in JIS G4305: 2005 can be applied.
〔銅被覆鋼箔〕
負極の集電体としては上記のステンレス鋼の他、銅被覆鋼箔を適用することができる。図１に銅被覆鋼箔の断面構造を模式的に示す。銅被覆鋼箔１０は、鋼基材１を芯材とし、その両面にそれぞれ銅被覆層２を有している。銅被覆層２は、電気銅めっきや、クラッド圧延によって形成することができる。電気銅めっきによる場合には、電気銅めっき鋼板を圧延して所定厚さの箔とする方法や、あらかじめ箔にまで圧延した鋼箔の表面に電気銅めっきを施す方法が適用できる。クラッド圧延による場合は、芯材となる鋼板あるいは鋼箔の両面に銅板あるいは銅箔を重ねてクラッド圧延し、必要に応じてさらに圧延することにより所定厚さの箔とすればよい。
[Copper coated steel foil]
In addition to the above stainless steel, a copper-coated steel foil can be applied as the negative electrode current collector. FIG. 1 schematically shows a cross-sectional structure of a copper-coated steel foil. The copper-coated
芯材となる鋼基材としては、普通鋼やステンレス鋼が適用できる。普通鋼としては例えば以下の成分組成範囲を例示することができる。
普通鋼；
質量％で、Ｃ：０.００１〜０.１５％、Ｓｉ：０.００１〜０.１％、Ｍｎ：０.００５〜０.６％、Ｐ：０.００１〜０.０５％、Ｓ：０.００１〜０.５％、Ａｌ：０.００１〜０.５％、Ｎｉ：０.００１〜１.０％、Ｃｒ：０.００１〜１.０％、Ｃｕ：０〜０.１％、Ｔｉ：０〜０.５％、Ｎｂ：０〜０.５％、Ｎ：０〜０.０５％、残部Ｆｅおよび不可避的不純物。
規格鋼種の中では、例えばＪＩＳ Ｇ３１４１：２００９に規定される冷延鋼板（鋼帯を含む）を素材とするものが適用できる。
As the steel base material used as the core material, ordinary steel or stainless steel can be applied. Examples of the normal steel include the following component composition ranges.
Ordinary steel;
In mass%, C: 0.001 to 0.15%, Si: 0.001 to 0.1%, Mn: 0.005 to 0.6%, P: 0.001 to 0.05%, S: 0.001 to 0.5%, Al: 0.001 to 0.5%, Ni: 0.001 to 1.0%, Cr: 0.001 to 1.0%, Cu: 0 to 0.1% , Ti: 0 to 0.5%, Nb: 0 to 0.5%, N: 0 to 0.05%, balance Fe and inevitable impurities.
Among standard steel types, for example, a material made of a cold-rolled steel sheet (including a steel strip) defined in JIS G3141: 2009 can be applied.
銅被覆鋼箔の鋼基材として用いるステンレス鋼としては、上述のオーステナイト系またはフェライト系の成分組成範囲のものが適用できるが、フェライト系鋼種の場合にはＣｒ含有量の下限を１０.５質量％まで拡張することができる。 As the stainless steel used as the steel substrate of the copper-coated steel foil, the above-mentioned austenitic or ferritic component composition ranges can be applied. In the case of a ferritic steel type, the lower limit of the Cr content is 10.5 mass. Can be expanded to 50%.
銅被覆層の片面当たりの平均膜厚ｔCuがあまり薄くなると下地の鋼基材まで貫通する欠陥（めっきの場合は主としてピンホール欠陥）が存在しやすく、従来の銅箔と同等の表面特性を得ようとするうえでは不利となる。ｔCuは０.００２μｍ以上を確保することが望ましい。また、鋼基材に普通鋼を適用する場合には、耐食性の観点からｔCuを０.０２μｍ以上とすることがより好ましい。一方、銅被覆層を過剰に形成させることは不経済となる。通常、片面当たりの平均膜厚ｔCuは５.０μｍ以下とすればよい。なお、銅被覆層の膜厚は箔の両面において必ずしも同じとする必要はなく、それぞれの表面側でｔCuが０.００２〜５.０μｍより好ましくは０.０２〜５.０μｍの範囲に収まっていれば好適である。 If the average film thickness t Cu per side of the copper coating layer is too thin, defects that penetrate to the underlying steel substrate (mainly pinhole defects in the case of plating) tend to exist and surface characteristics equivalent to those of conventional copper foils. It is disadvantageous when trying to get. It is desirable to secure t Cu of 0.002 μm or more. When ordinary steel is applied to the steel substrate, t Cu is more preferably 0.02 μm or more from the viewpoint of corrosion resistance. On the other hand, it is uneconomical to form an excessive copper coating layer. Usually, the average film thickness t Cu per side may be set to 5.0 μm or less. The film thickness of the copper coating layer is not necessarily the same on both sides of the foil, and t Cu is within the range of 0.002 to 5.0 μm, more preferably 0.02 to 5.0 μm on each surface side. If it is, it is suitable.
両面の銅被覆層の膜厚を含めた銅被覆鋼箔の平均厚さをｔとするとき、それぞれの表面側の銅被覆層においてｔCu／ｔが０.３以下であることが望ましい。ｔCu／ｔが０.３を超えると板厚に占める軟質な銅被覆層の割合が大きくなって、帯状金属箔としての引張強さを４５０ＭＰａ以上とするためには圧延率を相当に高める必要があるなど製造上の制約が大きくなる。また、活物質を担持させるためのロールプレスにおいて銅被覆層が塑性変形しやすくなり箔の形状不良（中伸び）を引き起こす要因となる。ｔCu／ｔは０.２以下、あるいはさらに０.１以下とすることがより好ましい。 When the average thickness of the copper-coated steel foil including the film thickness of the copper coating layers on both sides is t, it is desirable that t Cu / t is 0.3 or less in each copper coating layer on the surface side. When t Cu / t exceeds 0.3, the ratio of the soft copper coating layer occupying the plate thickness increases, and in order to increase the tensile strength as a strip metal foil to 450 MPa or more, it is necessary to considerably increase the rolling rate. There are large restrictions on manufacturing. In addition, in the roll press for supporting the active material, the copper coating layer is easily plastically deformed, which causes a defective shape (medium elongation) of the foil. t Cu / t is more preferably 0.2 or less, or even 0.1 or less.
なお、銅被覆鋼箔の製造工程に関して、本出願人らは特願２０１１−１３３５５６号に開示した。当該開示に従えば本発明で適用対象となる銅被覆鋼箔が好適に製造できる。 In addition, regarding the manufacturing process of copper clad steel foil, the present applicants disclosed in Japanese Patent Application No. 2011-133556. According to the disclosure, a copper-coated steel foil that is an object of application in the present invention can be suitably manufactured.
〔巻回し型電極積層体の製造〕
本発明に従う電極積層体は、少なくとも１つの帯状金属箔に引張強さが４５０〜９００ＭＰａと高いものを適用することを除き、基本的に従来一般的な巻き取り方法（例えば特許文献１）によって製造することができる。ただし、引張強さが高い帯状金属箔（ここでは「高強度帯状金属箔」という）を適用することによるメリットを十分に発揮させるためには、当該高強度帯状金属箔に付与する巻き回し時の張力を高めることが望ましい。上述のように巻き回しに供する帯状部材のうち少なくとも１つに高い張力を付与することができれば、巻き終えて完成した巻回し型電極積層体に強い締め付け力を付与することが可能となり、それによって巻き緩みや巻きズレに対する抵抗力が増大する。種々検討の結果、巻き緩みや巻きズレに対する抵抗力を十分に付与するためには、高強度帯状金属箔に対して４００ＭＰａ以上の張力を付与した状態で巻き回すことが極めて効果的である。ただし、その張力による箔の塑性変形を防止し、かつ弾性変形も過剰にならないように配慮する必要がある。発明者らの検討によれば、引張強さ４５０〜９００ＭＰａの高強度帯状金属箔に付与する巻き回し時の張力は、当該高強度帯状金属箔の引張強さの９０％以下の応力範囲とすることが好ましい。
[Manufacture of wound electrode laminates]
The electrode laminate according to the present invention is basically manufactured by a conventional general winding method (for example, Patent Document 1), except that at least one strip-shaped metal foil having a high tensile strength of 450 to 900 MPa is applied. can do. However, in order to fully demonstrate the merit of applying a strip metal foil having a high tensile strength (herein referred to as “high-strength strip metal foil”), at the time of winding applied to the high-strength strip metal foil It is desirable to increase the tension. If a high tension can be applied to at least one of the belt-shaped members used for winding as described above, it becomes possible to apply a strong clamping force to the wound electrode laminate that has been completed by winding. Resistance to winding looseness and winding deviation increases. As a result of various studies, in order to sufficiently impart resistance against winding looseness and winding deviation, it is extremely effective to wind the high-strength strip metal foil with a tension of 400 MPa or more. However, it is necessary to consider that the plastic deformation of the foil due to the tension is prevented and the elastic deformation is not excessive. According to the study by the inventors, the winding tension applied to the high-strength strip metal foil having a tensile strength of 450 to 900 MPa is within a stress range of 90% or less of the tensile strength of the high-strength strip metal foil. It is preferable.
〔帯状金属箔〕
集電体用の金属箔として以下の帯状金属箔を用意した。
・アルミニウム箔； 厚さ２０μｍ、引張強さ１００ＭＰａに調整された、従来のリチウムイオン二次電池の正極集電体に使用実績のあるもの。
・銅箔； 厚さ２０μｍ、引張強さ２２０ＭＰａに調整された、従来のリチウムイオン二次電池の負極集電体に使用実績のあるもの。
・ステンレス鋼箔Ａ； ＪＩＳ Ｇ４３０５：２００５に規定されるオーステナイト系ステンレス鋼ＳＵＳ３０４の組成を満たし、厚さ２０μｍ、引張強さ８００ＭＰａに調整されたもの。
・ステンレス鋼箔Ｆ； ＪＩＳ Ｇ４３０５：２００５に規定されるフェライト系ステンレス鋼ＳＵＳ４３０の組成を満たし、厚さ２０μｍ、引張強さ８００ＭＰａに調整されたもの。
・銅被覆鋼箔Ｐ； 鋼基材としてＪＩＳ Ｇ３１４１：２００９に規定される冷延鋼板を素材とするものを使用して、その両面に電気銅めっき層を形成し、圧延する手法により、片面当たりの銅被覆層の平均膜厚ｔCu、トータル厚さｔ、および引張強さを所定の値（表１中に記載）に調整したもの。ただし、両面の銅被覆層の平均膜厚は均等とした。
・銅被覆鋼箔Ｃ； 鋼基材としてＪＩＳ Ｇ３１４１：２００９に規定される冷延鋼板を素材とするものを使用して、その両面に銅板あるいは銅箔を重ね合わせてクラッド圧延する工程を経ることにより、片面当たりの銅被覆層の平均膜厚ｔCu、トータル厚さｔ、および引張強さを所定の値（表１中に記載）に調整したもの。ただし、両面の銅被覆層の平均膜厚は均等とした。
[Striped metal foil]
The following strip-shaped metal foils were prepared as metal foils for current collectors.
-Aluminum foil; one having a track record of use as a positive electrode current collector of a conventional lithium ion secondary battery, adjusted to a thickness of 20 μm and a tensile strength of 100 MPa.
-Copper foil; one that has been used for a negative electrode current collector of a conventional lithium ion secondary battery, adjusted to a thickness of 20 μm and a tensile strength of 220 MPa.
-Stainless steel foil A; satisfying the composition of austenitic stainless steel SUS304 specified in JIS G4305: 2005, adjusted to a thickness of 20 μm and a tensile strength of 800 MPa.
-Stainless steel foil F; satisfying the composition of ferritic stainless steel SUS430 specified in JIS G4305: 2005, adjusted to a thickness of 20 μm and a tensile strength of 800 MPa.
・ Copper-coated steel foil P: Using a steel base material made of a cold-rolled steel sheet specified in JIS G3141: 2009, forming an electrolytic copper-plated layer on both sides, and rolling it, A copper coating layer having an average film thickness t Cu , a total thickness t, and a tensile strength adjusted to predetermined values (described in Table 1). However, the average film thickness of the copper coating layers on both sides was made uniform.
・ Copper-coated steel foil C: Using a steel base made of a cold-rolled steel sheet as defined in JIS G3141: 2009, and performing a clad rolling process with a copper plate or copper foil superimposed on both sides By adjusting the average film thickness t Cu , the total thickness t, and the tensile strength of the copper coating layer per side to predetermined values (described in Table 1). However, the average film thickness of the copper coating layers on both sides was made uniform.
〔帯状正極部材〕
正極活物質（コバルト酸リチウム（ＬｉＣｏＯ2））９１質量部、導電材（グラファイト）６質量部、バインダー（ＰＶｄＦ）３質量部からなる混合物をＮ−メチル−２−ピロリドンに分散させてスラリーとし、このスラリーを上記帯状金属箔のうち正極に使用する箔（表１中に記載）の両面に均等に塗布したのち乾燥させて塗膜層とし、ロールプレスにより塗膜層を高密度化して活物質層とする手法により、正極活物質を表面に担持した帯状正極部材を得た。各帯状正極部材の活物質層の厚さおよび密度は同等とした。
[Strip-shaped positive electrode member]
A mixture of 91 parts by mass of a positive electrode active material (lithium cobaltate (LiCoO 2 )), 6 parts by mass of a conductive material (graphite) and 3 parts by mass of a binder (PVdF) was dispersed in N-methyl-2-pyrrolidone to form a slurry, The slurry is applied evenly on both sides of the foil (described in Table 1) used for the positive electrode of the strip-shaped metal foil, and then dried to form a coating film layer. A belt-like positive electrode member carrying the positive electrode active material on the surface was obtained by the technique of forming a layer. The thickness and density of the active material layer of each strip-like positive electrode member were made equal.
〔帯状負極部材〕
負極活物質（人造黒鉛）９０質量部、バインダー（ＰＶｄＦ）１０質量部からなる混合物をＮ−メチル−２−ピロリドンに分散させてスラリーとし、このスラリーを上記帯状金属箔のうち負極に使用する箔（表１中に記載）の両面に均等に塗布したのち乾燥させて塗膜層とし、ロールプレスにより塗膜層を高密度化して活物質層とする手法により、負極活物質を表面に担持した帯状負極部材を得た。各帯状負極部材の活物質層の厚さおよび密度は同等とした。
[Strip-shaped negative electrode member]
A mixture of 90 parts by weight of a negative electrode active material (artificial graphite) and 10 parts by weight of a binder (PVdF) is dispersed in N-methyl-2-pyrrolidone to form a slurry. The negative electrode active material was supported on the surface by a method in which the film was uniformly coated on both surfaces (described in Table 1) and dried to form a coating layer, and the coating layer was densified by a roll press to form an active material layer. A strip-shaped negative electrode member was obtained. The thickness and density of the active material layer of each strip-shaped negative electrode member were made equal.
〔巻回し型電極積層体〕
帯状正極部材１本、帯状負極部材１本、および厚さ２５μｍの微多孔性ポリプロピレンからなる帯状セパレータ２本を、帯状正極部材と帯状負極部材の間に１本の帯状セパレータが介在するように４層に重ね合わせてリールに巻き取る従来一般的な手法により巻回し型電極積層体を作製した。ただし、巻き回し時に帯状正極部材および帯状負極部材に付与する張力（巻取張力）は種々変化させた。各帯状部材の幅は５６ｍｍである。帯状セパレータには２本とも１００ＭＰａの張力（各例共通）を付与した。帯状正極部材と帯状負極部材の組合せおよび付与した張力の値は表１中に示してある。各巻回し型電極積層体は最大外径が１７ｍｍとなるように共通のサイズとした。
[Winded electrode laminate]
One belt-like positive electrode member, one belt-like negative electrode member, and two belt-like separators made of microporous polypropylene having a thickness of 25 μm are arranged so that one belt-like separator is interposed between the belt-like positive electrode member and the belt-like negative electrode member. A wound electrode laminate was produced by a conventional general method of stacking on a layer and winding on a reel. However, the tension (winding tension) applied to the strip-shaped positive electrode member and the strip-shaped negative electrode member during winding was variously changed. The width of each strip member is 56 mm. The two strip separators were each given a tension of 100 MPa (common to each example). Table 1 shows the combination of the strip-shaped positive electrode member and the strip-shaped negative electrode member and the applied tension values. The wound electrode laminates had a common size so that the maximum outer diameter was 17 mm.
〔リチウムイオン二次電池〕
電解液として、エチレンカーボネートとジエチレンカーボネートを１：１の体積比で混合した溶媒中にＬｉＰＦ6を１ｍｏｌ／Ｌ濃度で溶解させた液を用意した。上記の巻回し型電極積層体と電解液が鉄製の電池缶に収容され封止された構造のリチウムイオン二次電池を作製した。巻回し型電極積層体の負極集電体は電池缶に電気的に接続され、正極集電体は電池缶から絶縁された極板に電気的に接続されている。
[Lithium ion secondary battery]
As an electrolytic solution, a solution was prepared by dissolving LiPF 6 at a concentration of 1 mol / L in a solvent in which ethylene carbonate and diethylene carbonate were mixed at a volume ratio of 1: 1. A lithium ion secondary battery having a structure in which the wound electrode laminate and the electrolytic solution were housed in an iron battery can and sealed was produced. The negative electrode current collector of the wound electrode laminate is electrically connected to the battery can, and the positive electrode current collector is electrically connected to an electrode plate insulated from the battery can.
〔電池性能の評価〕
各電池について、活物質が有する理論容量（ｍＡｈ）を計算により求めた。次に、理論容量（ｍＡｈ）／５（ｈ）で示される電流値を用いて完全充電した後、同じ電流値で放電を行った。このときの放電容量を各電池の電池容量（ｍＡｈ）とした。引き続き、１.０ＣｍＡの一定の充電率で完全充電した後、１.０ＣｍＡの一定の放電率で放電するサイクルを繰り返し、５サイクル目の活物質層単位体積当たりの放電容量Ｑ5（ｍＡｈ）および２００サイクル目の活物質層単位体積当たりの放電容量Ｑ200（ｍＡｈ）を測定した。試験温度は２５℃である。ここで、充電率および放電率は下記（１）式および（２）式によって表される。
充電率（ＣｍＡ）＝電池容量（ｍＡｈ）／充電時間（ｈ） …（１）
放電率（ＣｍＡ）＝電池容量（ｍＡｈ）／放電時間（ｈ） …（２）
電池性能の評価は、下記（３）式で定義される放電容量比率によって行った。
放電容量比率（％）＝Ｑ200（ｍＡｈ）／Ｑ5（ｍＡｈ）×１００ …（３）
放電容量比率の値が大きいほど、電池寿命に優れると評価される。結果を表１に示す。
[Evaluation of battery performance]
About each battery, the theoretical capacity | capacitance (mAh) which an active material has was calculated | required by calculation. Next, after fully charging using the current value indicated by the theoretical capacity (mAh) / 5 (h), discharging was performed at the same current value. The discharge capacity at this time was defined as the battery capacity (mAh) of each battery. Subsequently, after fully charging at a constant charge rate of 1.0 CmA, a cycle of discharging at a constant discharge rate of 1.0 CmA is repeated, and the discharge capacity Q 5 (mAh) per unit volume of the active material layer in the fifth cycle is repeated. The discharge capacity Q 200 (mAh) per unit volume of the active material layer at the 200th cycle was measured. The test temperature is 25 ° C. Here, the charge rate and the discharge rate are expressed by the following formulas (1) and (2).
Charging rate (CmA) = battery capacity (mAh) / charging time (h) (1)
Discharge rate (CmA) = battery capacity (mAh) / discharge time (h) (2)
The battery performance was evaluated based on the discharge capacity ratio defined by the following formula (3).
Discharge capacity ratio (%) = Q 200 (mAh) / Q 5 (mAh) × 100 (3)
The larger the value of the discharge capacity ratio, the better the battery life. The results are shown in Table 1.
従来例Ｎｏ.１は高強度帯状金属箔を適用していない従来の巻回し型電極積層体を用いたものである。本発明例であるＮｏ.３、５、７、１３は正極および負極の少なくとも一方の集電体に引張強さが４５０ＭＰａ以上の高強度帯状金属箔を適用し、巻取張力を従来例Ｎｏ.１と同等としたものであるが、いずれも放電容量維持率が従来例Ｎｏ.１より向上した。これは、高強度帯状金属箔において巻き回し時の張力に起因する弾性変形が抑制されたことにより当該集電体表面での活物質層の密着性が向上したためであると考えられる。それ以外の本発明例は正極および負極の少なくとも一方の集電体に引張強さが４５０ＭＰａ以上の高強度帯状金属箔を適用し、かつその高強度帯状金属箔の少なくとも一方に４００ＭＰａ以上の高い巻取張力を付与したものである。これらの例では放電容量維持率が更に向上した。これは、巻回し型電極積層体に強い締め付け力が付与されたことにより充放電サイクルを繰り返す過程での巻き緩みや巻きズレの発生が抑制されたためであると考えられる。 Conventional Example No. 1 uses a conventional wound electrode laminate to which a high-strength strip metal foil is not applied. Examples No. 3, 5, 7, and 13 of the present invention apply a high-strength strip metal foil having a tensile strength of 450 MPa or more to at least one of the current collectors of the positive electrode and the negative electrode, and the winding tension is the conventional example No. In all cases, the discharge capacity retention rate was improved from the conventional example No. 1. This is considered to be because the adhesiveness of the active material layer on the current collector surface was improved by suppressing the elastic deformation caused by the tension during winding in the high-strength metal strip. In other examples of the present invention, a high-strength strip metal foil having a tensile strength of 450 MPa or more is applied to at least one of the positive electrode and negative electrode current collectors, and a high winding of 400 MPa or more is applied to at least one of the high-strength strip metal foils. A tension is applied. In these examples, the discharge capacity retention rate was further improved. This is presumably because the occurrence of winding looseness and winding misalignment during the process of repeating the charge / discharge cycle was suppressed by applying a strong clamping force to the wound electrode laminate.
１ 鋼基材
２ 銅被覆層
１０ 銅被覆鋼箔
DESCRIPTION OF SYMBOLS 1
Claims (8)
第１の帯状金属箔がアルミニウム箔、第２の帯状金属箔が引張強さ４５０〜９００ＭＰａの銅被覆鋼箔であるリチウムイオン二次電池の電極積層体。 The belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil were overlapped and wound together with the belt-like separator. An electrode laminate of a lithium ion secondary battery,
The electrode laminated body of the lithium ion secondary battery whose 1st strip | belt-shaped metal foil is an aluminum foil, and a 2nd strip | belt-shaped metal foil is copper covering steel foil with the tensile strength of 450-900 MPa.
第１の帯状金属箔がアルミニウム箔、第２の帯状金属箔が引張強さ４５０〜９００ＭＰａかつＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔であるリチウムイオン二次電池の電極積層体。 The belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil were overlapped and wound together with the belt-like separator. An electrode laminate of a lithium ion secondary battery,
Electrode lamination of a lithium ion secondary battery in which the first strip metal foil is an aluminum foil, and the second strip metal foil is a stainless steel foil having a tensile strength of 450 to 900 MPa and a Cr content of 10.5 to 30.5 mass%. body.
第１の帯状金属箔が引張強さ４５０〜９００ＭＰａかつＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔、第２の帯状金属箔が銅箔であるリチウムイオン二次電池の電極積層体。 The belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil were overlapped and wound together with the belt-like separator. An electrode laminate of a lithium ion secondary battery,
Electrode lamination of a lithium ion secondary battery in which the first strip metal foil is a stainless steel foil having a tensile strength of 450 to 900 MPa and a Cr content of 10.5 to 30.5 mass%, and the second strip metal foil is a copper foil. body.
第１の帯状金属箔がＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔、第２の帯状金属箔が銅被覆鋼箔であり、前記第１および第２の帯状金属箔のうち少なくとも一方が引張強さ４５０〜９００ＭＰａの金属箔であるリチウムイオン二次電池の電極積層体。 The belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil were overlapped and wound together with the belt-like separator. An electrode laminate of a lithium ion secondary battery,
The first strip-shaped metal foil is a stainless steel foil having a Cr content of 10.5 to 30.5 mass%, the second strip-shaped metal foil is a copper-coated steel foil, and among the first and second strip-shaped metal foils An electrode laminate of a lithium ion secondary battery, at least one of which is a metal foil having a tensile strength of 450 to 900 MPa.
第１の帯状金属箔および第２の帯状金属箔がそれぞれＣｒ含有量１０.５〜３０.５質量％のステンレス鋼箔であり、前記第１および第２の帯状金属箔のうち少なくとも一方が引張強さ４５０〜９００ＭＰａの金属箔であるリチウムイオン二次電池の電極積層体。 The belt-like positive electrode member carrying the positive electrode active material on the surface of the first belt-like metal foil and the belt-like negative electrode member carrying the negative electrode active material on the surface of the second belt-like metal foil were overlapped and wound together with the belt-like separator. An electrode laminate of a lithium ion secondary battery,
Each of the first strip metal foil and the second strip metal foil is a stainless steel foil having a Cr content of 10.5 to 30.5 mass%, and at least one of the first and second strip metal foils is tensile. An electrode laminate of a lithium ion secondary battery, which is a metal foil having a strength of 450 to 900 MPa.
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| US20190363367A1 (en) * | 2017-03-17 | 2019-11-28 | Hitachi Metals, Ltd. | Foil for negative electrode collector of secondary battery and method for manufacturing the same |
| CN114784222A (en) * | 2021-03-29 | 2022-07-22 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| WO2023276757A1 (en) * | 2021-06-30 | 2023-01-05 | パナソニックＩｐマネジメント株式会社 | Lithium secondary battery |
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| JP2011146131A (en) * | 2010-01-12 | 2011-07-28 | Hitachi Ltd | Electrode for lithium secondary battery |
| JP2011526969A (en) * | 2009-07-13 | 2011-10-20 | コリア インスティチュート オブ マシーナリー アンド マテリアルズ | Austenitic stainless steel with high strength and high corrosion resistance added with carbon and nitrogen composite and method for producing the same |
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| JP2008098157A (en) * | 2006-09-14 | 2008-04-24 | Matsushita Electric Ind Co Ltd | Negative electrode for lithium ion secondary battery and lithium ion secondary battery using the negative electrode |
| JP2011526969A (en) * | 2009-07-13 | 2011-10-20 | コリア インスティチュート オブ マシーナリー アンド マテリアルズ | Austenitic stainless steel with high strength and high corrosion resistance added with carbon and nitrogen composite and method for producing the same |
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| US20190363367A1 (en) * | 2017-03-17 | 2019-11-28 | Hitachi Metals, Ltd. | Foil for negative electrode collector of secondary battery and method for manufacturing the same |
| US10868310B2 (en) * | 2017-03-17 | 2020-12-15 | Hitachi Metals, Ltd. | Negative electrode current collector foil including iron based alloy layer sandwiched between copper layers and method for manufacturing the same |
| CN114784222A (en) * | 2021-03-29 | 2022-07-22 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
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