JP2006278182A - Nonaqueous electrolyte secondary battery and manufacturing method of the same - Google Patents

Nonaqueous electrolyte secondary battery and manufacturing method of the same Download PDF

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JP2006278182A
JP2006278182A JP2005096829A JP2005096829A JP2006278182A JP 2006278182 A JP2006278182 A JP 2006278182A JP 2005096829 A JP2005096829 A JP 2005096829A JP 2005096829 A JP2005096829 A JP 2005096829A JP 2006278182 A JP2006278182 A JP 2006278182A
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electrode
negative electrode
curved corner
flat portion
corner portion
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Hideyuki Inomata
秀行 猪俣
Takuya Morimoto
卓弥 森本
Atsushi Obayashi
篤史 大林
Akiyoshi Tamaoki
日義 玉置
Ryuji Oshita
竜司 大下
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Sanyo Electric Co Ltd
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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
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    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • 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
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    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent an electrode plate from distortion while simplifying a manufacturing process of nonaqueous electrolyte secondary battery. <P>SOLUTION: The nonaqueous electrolyte secondary battery is provided with an electrode body 10 formed by laminating an anode 1B and a cathode 1A through a separator 3. An electrode plate 1 of the electrode body 10 has a planar flat part 6 and curved corner parts 7 curved in a prescribed radius of curvature. An activator layer 5 is adhered to a core body 4 of the anode 1B. Packing density of the curved corner part 7 of the activator layer 5 of the anode 1B is made smaller than that of the flat part 6, or the curved corner part 7 is made thicker than the flat part 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、主としてリチウムイオン二次電池である非水電解質二次電池に関する。   The present invention relates to a non-aqueous electrolyte secondary battery that is mainly a lithium ion secondary battery.

非水電解質二次電池であるリチウムイオン二次電池は、ニッケル水素電池やニッケルカドミウム電池等のアルカリ二次電池に比較してエネルギー密度を大きくできる特徴がある。この特徴は、正極と負極の充填密度を高くしてより向上できる。しかしながら、正極と負極の充填密度が高くなるほど、電池の充放電に伴う正極と負極の膨張・収縮による極板の歪みが大きくなる。とくに、負極は充電時に極板が膨張するが、このときに発生するひずみを電極体で吸収できなくなり、極板にたわみが発生する。その結果、電池の膨れが増大して、正常な形状を保つことができなくなる。さらに、極板のたわみによる反応の不均一は、電池の放電性能を低下させて、寿命も短くする。したがって、負極の膨張を抑える、あるいは何らかの手法でその影響を抑制することが非常に重要となる。この欠点を解消する電池は開発されている。（特許文献１ないし４参照）
特開２００３−４５４７４号公報 特開２００４−２１４１９０号公報 特開２００３−２８８９４３号公報 特開２０００−２０８１２９号公報 A lithium ion secondary battery, which is a nonaqueous electrolyte secondary battery, is characterized in that the energy density can be increased as compared with an alkaline secondary battery such as a nickel metal hydride battery or a nickel cadmium battery. This feature can be further improved by increasing the packing density of the positive and negative electrodes. However, the higher the packing density of the positive electrode and the negative electrode, the greater the distortion of the electrode plate due to the expansion / contraction of the positive electrode and the negative electrode that accompanies charging / discharging of the battery. Particularly, in the negative electrode, the electrode plate expands during charging, but the strain generated at this time cannot be absorbed by the electrode body, and the electrode plate bends. As a result, the swelling of the battery increases, and the normal shape cannot be maintained. Furthermore, the non-uniform reaction due to the deflection of the electrode plate reduces the discharge performance of the battery and shortens the life. Therefore, it is very important to suppress the expansion of the negative electrode or to suppress the influence by some technique. Batteries that eliminate this drawback have been developed. (See Patent Documents 1 to 4)
JP 2003-45474 A JP 2004-214190 A JP 2003-288934 A JP 2000-208129 A

特許文献１は、電極体の湾曲コーナー部の内側の活物質層を薄くして、極板の巻回部や折り曲げ部において、極板のひび割れ、切断、芯体からの活物質の脱落を防止する電池を記載している。この電池は、極板の湾曲コーナー部において活物質層を薄くするので、極板の製造が極めて複雑になる。それは、活物質層の厚さを変更すると共に、薄くしている部分を電極体の湾曲コーナー部に正確に一致させるからである。また、この構造によっては、充電時に極板が延びてたわむ弊害を有効に防止するのが難しい。   In Patent Document 1, the active material layer inside the curved corner portion of the electrode body is thinned to prevent cracking or cutting of the electrode plate and dropping of the active material from the core body at the winding or bending portion of the electrode plate. The battery to be described is described. In this battery, since the active material layer is thinned at the curved corner portion of the electrode plate, the manufacture of the electrode plate becomes extremely complicated. This is because the thickness of the active material layer is changed and the thinned portion is exactly matched with the curved corner portion of the electrode body. In addition, depending on this structure, it is difficult to effectively prevent the adverse effect that the electrode plate extends and bends during charging.

特許文献２はリチウム電池を記載している。この電池は、弾性係数を２．０ｋｇｆ／ｍｍ２以下とするセパレータを使用する。このリチウム電池は、充電時、電極板の膨張によって発生する電極体の変形をセパレータに吸収して抑制する。この構造の電池は、セパレータに極板のひずみを吸収させるために、セパレータを厚くする必要がある。このため、極板のひずみを充分に吸収できる構造とする電池は、セパレータが専有する体積が大きくなって、電池の充電容量が小さくなる欠点がある。 Patent Document 2 describes a lithium battery. This battery uses a separator having an elastic modulus of 2.0 kgf / mm 2 or less. This lithium battery absorbs and suppresses the deformation of the electrode body caused by the expansion of the electrode plate during charging. In the battery having this structure, it is necessary to make the separator thicker in order for the separator to absorb the strain of the electrode plate. For this reason, a battery having a structure capable of sufficiently absorbing the strain of the electrode plate has a drawback that the volume occupied by the separator is increased, and the charge capacity of the battery is reduced.

特許文献３は、極板膨張の歪みを負極と正極の両方に分散させる非水電解質二次電池を記載する。この電池は、正極の曲げ強度をＸ（ｍＮ／ｃｍ）とし、負極の曲げ強度をＹ（ｍＮ／ｃｍ）とした場合に、正極の曲げ強度に対する負極の曲げ強度の比率（Ｙ／Ｘ）が１０％以上になるように設定する。このように、正極の曲げ強度に対する負極の曲げ強度の比率（Ｙ／Ｘ）を１０％以上に設定すると、負極の曲げ強度が正極の曲げ強度に対して相対に大きくなる。これにより、リチウムの吸蔵による極板膨張による歪みの影響を負極と正極の両方に分散できる。この構造は、正極と負極の曲げ強度を特定の数値とするので、材料に制限を受け、また曲げ強度の比率によっては極板のひずみを充分に有効に吸収できなくなる欠点がある。   Patent Document 3 describes a non-aqueous electrolyte secondary battery in which distortion of electrode plate expansion is dispersed in both the negative electrode and the positive electrode. In this battery, when the bending strength of the positive electrode is X (mN / cm) and the bending strength of the negative electrode is Y (mN / cm), the ratio of the bending strength of the negative electrode to the bending strength of the positive electrode (Y / X) is Set to 10% or more. Thus, when the ratio (Y / X) of the negative electrode bending strength to the positive electrode bending strength is set to 10% or more, the negative electrode bending strength becomes relatively larger than the positive electrode bending strength. Thereby, the influence of the distortion by electrode plate expansion by occlusion of lithium can be dispersed in both the negative electrode and the positive electrode. This structure has a drawback that the bending strength of the positive electrode and the negative electrode is set to a specific value, so that the material is limited, and the strain of the electrode plate cannot be absorbed sufficiently effectively depending on the ratio of the bending strength.

特許文献４は、極板に生ずる波打ちやしわ等の歪みを低減するリチウムイオン二次電池を記載する。この電池は、芯体に活物質層を積層している正極及び負極をセパレータを介して巻芯外周に捲回している電極体を備える。正極の幅方向（Ｙ軸方向）端部に形成された電極活物質未塗工領域における芯体に、芯体の幅方向に平行なスリットを形成している。負極についても同様としている。この構造の電池は、特定の加工をするので製造工程が複雑になって製造コストが高くなる欠点がある。   Patent document 4 describes the lithium ion secondary battery which reduces distortions, such as a wave and a wrinkle which arise in an electrode plate. This battery includes an electrode body in which a positive electrode and a negative electrode, in which an active material layer is laminated on a core body, are wound around the outer periphery of a core via a separator. A slit parallel to the width direction of the core body is formed in the core body in the electrode active material uncoated region formed at the end in the width direction (Y-axis direction) of the positive electrode. The same applies to the negative electrode. The battery having this structure has a drawback in that the manufacturing process becomes complicated and the manufacturing cost increases because of specific processing.

本発明は、従来のこのような欠点を解決することを目的に開発されたものである。本発明の重要な目的は、簡単かつ容易に、しかも安価に多量生産しながら極板のひずみを有効に防止できる非水電解質二次電池とその製造方法を提供することにある。   The present invention has been developed for the purpose of solving the conventional drawbacks. An important object of the present invention is to provide a non-aqueous electrolyte secondary battery that can effectively prevent distortion of an electrode plate while easily and easily mass-producing it at low cost, and a method for manufacturing the same.

本発明の非水電解質二次電池は、前述の目的を達成するために以下の構成を備える。非水電解質二次電池は、負極１Ｂと正極１Ａとをセパレータ３を介して積層している電極体１０を備える。この電極体１０の極板１は、負極１Ｂと正極１Ａを平面状として積層している平坦部６と、この平坦部６に連結されて所定の曲率半径で湾曲する状態で積層している湾曲コーナー部７とからなる。負極１Ｂは芯体４に活物質層５を付着している。負極１Ｂの活物質層５は、湾曲コーナー部７の充填密度を平坦部６の充填密度よりも小さくし、あるいは平坦部６よりも湾曲コーナー部７を厚くしている。   The nonaqueous electrolyte secondary battery of the present invention has the following configuration in order to achieve the above-described object. The nonaqueous electrolyte secondary battery includes an electrode body 10 in which a negative electrode 1B and a positive electrode 1A are stacked with a separator 3 interposed therebetween. The electrode plate 10 of the electrode body 10 has a flat portion 6 in which the negative electrode 1B and the positive electrode 1A are laminated in a flat shape, and a curved portion that is connected to the flat portion 6 and is bent at a predetermined radius of curvature. It consists of a corner portion 7. The negative electrode 1 </ b> B has an active material layer 5 attached to the core body 4. In the active material layer 5 of the negative electrode 1 </ b> B, the filling density of the curved corner portion 7 is made smaller than the filling density of the flat portion 6, or the curved corner portion 7 is made thicker than the flat portion 6.

本発明の非水電解質二次電池は、好ましくは、負極１Ｂの湾曲コーナー部７と平坦部６の充填密度の差を１％以上とし、あるいは、負極１Ｂの湾曲コーナー部７と平坦部６の厚さの差を１％以上とする。   In the nonaqueous electrolyte secondary battery of the present invention, preferably, the difference in filling density between the curved corner portion 7 and the flat portion 6 of the negative electrode 1B is set to 1% or more, or the curved corner portion 7 and the flat portion 6 of the negative electrode 1B are The thickness difference is 1% or more.

さらに、本発明の非水電解質二次電池は、活物質層５の充填密度を１．４０ｇ／ｃｃ以上とする。   Furthermore, in the nonaqueous electrolyte secondary battery of the present invention, the packing density of the active material layer 5 is 1.40 g / cc or more.

さらに、本発明の非水電解質二次電池の製造方法は、負極１Ｂと正極１Ａとをセパレータ３を介して積層して渦巻状に巻く巻き工程と、巻き工程で得られた電極の巻き取り体１１を、両面からプレスして、極板１を平坦部６と湾曲コーナー部７とするプレス工程と、プレス工程で得られた電極体１０を外装缶２０に入れて、外装缶２０の開口部を閉塞する組立工程とで非水電解質二次電池を製造する。この製造方法は、プレス工程において、負極１Ｂの湾曲コーナー部７における活物質層５の充填密度を平坦部６の活物質層５の充填密度よりも小さくし、あるいは、湾曲コーナー部７の活物質層５を平坦部６の活物質層５よりも厚くすると共に、平坦部６と湾曲コーナー部７の充填密度の差を、あるいは厚さの差を１％以上としている。   Furthermore, the manufacturing method of the non-aqueous electrolyte secondary battery of the present invention includes a winding process in which the negative electrode 1B and the positive electrode 1A are stacked via a separator 3 and wound in a spiral shape, and an electrode winding body obtained in the winding process. 11 is pressed from both sides, the electrode plate 1 is made into a flat part 6 and a curved corner part 7, and the electrode body 10 obtained by the pressing process is put into the outer can 20, and the opening of the outer can 20 A non-aqueous electrolyte secondary battery is manufactured through an assembly process for closing the battery. In this manufacturing method, in the pressing step, the packing density of the active material layer 5 in the curved corner portion 7 of the negative electrode 1B is made smaller than the packing density of the active material layer 5 in the flat portion 6, or the active material of the curved corner portion 7 is used. The layer 5 is made thicker than the active material layer 5 of the flat part 6, and the difference in filling density between the flat part 6 and the curved corner part 7 or the difference in thickness is 1% or more.

本発明は、簡単かつ容易に、しかも安価に多量生産しながら極板のひずみを有効に阻止できる特徴がある。それは、本発明の非水電解質二次電池とその製造方法が、負極の湾曲コーナー部の充填密度を平坦部の充填密度よりも小さくし、あるいは湾曲コーナー部を平坦部よりも厚くしているからである。この構造の負極は、充放電によって負極が膨張・収縮しても、そのひずみを、充填密度を低くしている湾曲コーナー部で吸収できる。負極にたわみが発生して正極と負極の反応が不均一になると、電池の放電性能が低下して寿命が短くなるが、本発明は負極のたわみを有効に阻止して、充放電サイクル後における電池容量の低下を著しく少なくできる。   The present invention has a feature that it is possible to effectively prevent strain of the electrode plate while easily and easily mass-producing it at low cost. This is because the nonaqueous electrolyte secondary battery of the present invention and the manufacturing method thereof make the filling density of the curved corner portion of the negative electrode smaller than the filling density of the flat portion, or make the curved corner portion thicker than the flat portion. It is. Even if the negative electrode expands and contracts due to charge and discharge, the negative electrode having this structure can absorb the distortion at the curved corner portion where the packing density is lowered. When deflection occurs in the negative electrode and the reaction between the positive electrode and the negative electrode becomes non-uniform, the discharge performance of the battery is reduced and the life is shortened, but the present invention effectively prevents the deflection of the negative electrode, and after the charge / discharge cycle Battery capacity can be significantly reduced.

また、本発明は、電極の巻き取り体をプレスする工程で、平坦部の充填密度を湾曲コーナー部の充填密度よりも高くでき、また、湾曲コーナー部を平坦部よりも厚くできるので、極板を特別な方法で製造することなく、従来の方法と同じように簡単かつ容易に、しかも能率よく優れた特性の非水電解質二次電池を製造できる特徴がある。   Further, in the present invention, in the step of pressing the electrode winding body, the filling density of the flat portion can be made higher than the filling density of the curved corner portion, and the curved corner portion can be made thicker than the flat portion. Thus, there is a feature that a non-aqueous electrolyte secondary battery having excellent characteristics can be manufactured simply and easily as well as efficiently without using a special method.

以下、本発明の実施例を図面に基づいて説明する。ただし、以下に示す実施例は、本発明の技術思想を具体化するための非水電解質二次電池を例示するものであって、本発明は非水電解質二次電池を以下のものに特定しない。   Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate non-aqueous electrolyte secondary batteries for embodying the technical idea of the present invention, and the present invention does not specify non-aqueous electrolyte secondary batteries as follows. .

さらに、この明細書は、特許請求の範囲を理解しやすいように、実施例に示される部材に対応する番号を、「特許請求の範囲」および「課題を解決するための手段の欄」に示される部材に付記している。ただ、特許請求の範囲に示される部材を、実施例の部材に特定するものでは決してない。   Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

図１に示す渦巻式電極の電池は角型電池で、角型の外装缶２０に、電極体１０と電解液を入れて開口部を封口板２１で密閉している。電極体１０は、正極１Ａの極板１と負極１Ｂの極板１を、セパレータ３を挟んで積層して捲回したものである。以下の実施例は、非水電解質二次電池をリチウムイオン二次電池として詳述する。   The spiral electrode battery shown in FIG. 1 is a prismatic battery, in which an electrode body 10 and an electrolytic solution are placed in a rectangular outer can 20 and the opening is sealed with a sealing plate 21. The electrode body 10 is obtained by laminating the electrode plate 1 of the positive electrode 1 </ b> A and the electrode plate 1 of the negative electrode 1 </ b> B with the separator 3 interposed therebetween. In the following examples, the non-aqueous electrolyte secondary battery will be described in detail as a lithium ion secondary battery.

電池の極板１は、図２の拡大断面図に示すように、芯体４の表面に活物質層５を積層している。芯体４は金属箔である。芯体４を金属箔とする電極体１０は、極板１の電気抵抗を小さくできる。芯体４の金属箔は、アルミニウム箔や銅箔等である。リチウムイオン二次電池は、正極１Ａの芯体４をアルミニウム箔とし、負極１Ｂの芯体４を銅箔とする。   As shown in the enlarged sectional view of FIG. 2, the electrode plate 1 of the battery has an active material layer 5 laminated on the surface of the core body 4. The core body 4 is a metal foil. The electrode body 10 having the core body 4 as a metal foil can reduce the electric resistance of the electrode plate 1. The metal foil of the core body 4 is an aluminum foil or a copper foil. In the lithium ion secondary battery, the core 4 of the positive electrode 1A is an aluminum foil, and the core 4 of the negative electrode 1B is a copper foil.

極板１は、活物質ペーストを芯体４の表面に塗布し、これを乾燥させて活物質層５を設けている。乾燥された活物質層５は、予備プレスして所定の充填密度に調整される。予備プレスは、一対のローラー間に、乾燥された活物質層５を芯体４に積層している極板１を通過させて、活物質層５を所定の充填密度とする。この予備プレスにおいて、負極１Ｂの活物質層５の充填密度は１．６５ｇ／ｃｃ以下、好ましくは１．６ｇ／ｃｃ以下とする。予備プレスで活物質層５の充填密度を高くすると、電極体１０の両面を挟着して平坦部６を設けるプレス工程において、極板１の平坦部６と湾曲コーナー部７との充填密度の差を設けるのが難しくなるからである。さらに、この予備プレスにおいて、活物質層５は、充填密度を好ましくは１．４ｇ／ｃｃ以上とする。活物質層５の充填密度を１．４ｇ／ｃｃ以下とすると、電池の容量が小さくなるからである。   The electrode plate 1 is provided with an active material layer 5 by applying an active material paste to the surface of the core body 4 and drying it. The dried active material layer 5 is pre-pressed and adjusted to a predetermined packing density. In the preliminary press, the electrode plate 1 in which the dried active material layer 5 is laminated on the core body 4 is passed between a pair of rollers, so that the active material layer 5 has a predetermined packing density. In this preliminary pressing, the packing density of the active material layer 5 of the negative electrode 1B is 1.65 g / cc or less, preferably 1.6 g / cc or less. When the filling density of the active material layer 5 is increased by preliminary pressing, the filling density of the flat portion 6 and the curved corner portion 7 of the electrode plate 1 is increased in a pressing process in which both surfaces of the electrode body 10 are sandwiched to provide the flat portion 6. This is because it is difficult to make a difference. Further, in this preliminary press, the active material layer 5 preferably has a packing density of 1.4 g / cc or more. This is because if the packing density of the active material layer 5 is 1.4 g / cc or less, the capacity of the battery is reduced.

活物質層５の充填密度は、極板１を通過させる一対のローラーが極板１を挟着する押圧力でコントロールする。たとえばローラーの単位長さに対する圧力を３９２０Ｎ／ｃｍ（４００ｋｇｆ／ｃｍ）として、活物質層５の充填密度を１．６ｇ／ｃｃとし、３１３６Ｎ／ｃｍ（３２０ｋｇｆ／ｃｍ）として、活物質層５の充填密度を１．５５ｇ／ｃｃにできる。   The packing density of the active material layer 5 is controlled by the pressing force with which the pair of rollers that pass the electrode plate 1 sandwich the electrode plate 1. For example, the pressure for the unit length of the roller is 3920 N / cm (400 kgf / cm), the filling density of the active material layer 5 is 1.6 g / cc, and the filling of the active material layer 5 is 3136 N / cm (320 kgf / cm). The density can be 1.55 g / cc.

セパレータ３は、ポリプロピレン等のプラスチック製の微多孔膜である。ただ、セパレータ３は、正極１Ａと負極１Ｂを絶縁して電解液やイオンを通過させる全てのものが使用できる。したがって、セパレータ３には、プラスチック繊維を立体的に集合してシート状にプレスした不織布も使用できる。   The separator 3 is a microporous film made of plastic such as polypropylene. However, as the separator 3, any separator that can insulate the positive electrode 1 </ b> A and the negative electrode 1 </ b> B and pass the electrolytic solution or ions can be used. Therefore, the separator 3 can also be a nonwoven fabric in which plastic fibers are gathered three-dimensionally and pressed into a sheet shape.

電極体１０は、渦巻状に巻かれた巻き取り体１１を、両面から挟むようにプレスして電極体１０とする。プレスする押圧板は、巻き取り体１１を押圧する押圧面を平滑な平面としている。この電極体１０は、平坦部６の両側がプレスされず、所定の曲率半径で湾曲する湾曲コーナー部７となる。   The electrode body 10 is pressed into a winding body 11 wound in a spiral shape so as to be sandwiched from both sides to form an electrode body 10. The pressing plate to be pressed has a pressing surface that presses the wound body 11 as a smooth flat surface. The electrode body 10 is a curved corner portion 7 that is not pressed on both sides of the flat portion 6 and is curved with a predetermined radius of curvature.

図３と図４は、本発明の電池と従来の電池の電極体１０を示す。これ等の図は、極板１を渦巻状に捲回した巻き取り体１１の状態→巻き取り体１１をプレス加工した状態→電極体１０を充放電した状態を示している。なお、これらの図は、本発明の特徴を理解しやすくするために、負極１Ｂの極板のみを示しているが、現実には、図２に示すように、正極１Ａの極板、セパレータ３も共に捲回している。また、これらの図では、極板１を同心円状に配置しているが、現実の電極体は、図２に示すように、極板１を渦巻状に捲回している。   3 and 4 show an electrode body 10 of the battery of the present invention and a conventional battery. These drawings show a state of the wound body 11 wound around the electrode plate 1 → a state where the wound body 11 is pressed → a state where the electrode body 10 is charged / discharged. These drawings only show the electrode plate of the negative electrode 1B for easy understanding of the features of the present invention, but in reality, as shown in FIG. 2, the electrode plate of the positive electrode 1A and the separator 3 are shown. Are both playing around. In these drawings, the electrode plates 1 are arranged concentrically. However, in the actual electrode body, the electrode plates 1 are wound in a spiral shape as shown in FIG.

図３は本発明の電極体１０を示し、図４は従来の電極体１０を示す。従来の電極体１０は、巻き取り体１１をプレスした状態で、平坦部６と湾曲コーナー部７の厚さを等しくしている。厳密に解釈すると、平坦部６と湾曲コーナー部７との厚さはわずかに異なる。ただ、平坦部６と湾曲コーナー部７の厚さの差は、有効数字を３桁とする測定においては全く同じ値となるので、実質的には同じ厚さである。この電極体１０を充放電させると負極１Ｂが膨張し、平坦部６と湾曲コーナー部７で押し合って、図に示すようにたわみが発生する。本発明の電極体１０は、図３に示すように、平坦部６を湾曲コーナー部７よりも薄くプレスして、平坦部６の充填密度を湾曲コーナー部７よりも高く、いいかえると湾曲コーナー部７の充填密度を平坦部６よりも低くしている。充填密度の低い湾曲コーナー部７は、平坦部６の応力や伸び吸収する。また、充填密度の低い湾曲コーナー部７は、膨張による押圧力も小さくなる。したがって、湾曲コーナー部７が負極１Ｂのひずみを吸収する緩衝部として作用して、極板１のたわみを有効に防止する。   FIG. 3 shows an electrode body 10 of the present invention, and FIG. 4 shows a conventional electrode body 10. In the conventional electrode body 10, the thickness of the flat portion 6 and the curved corner portion 7 are made equal in a state where the winding body 11 is pressed. When strictly interpreted, the thicknesses of the flat portion 6 and the curved corner portion 7 are slightly different. However, the difference between the thicknesses of the flat portion 6 and the curved corner portion 7 is the same value in the measurement in which the significant number is three digits, and thus is substantially the same thickness. When this electrode body 10 is charged and discharged, the negative electrode 1B expands and presses at the flat portion 6 and the curved corner portion 7 to cause deflection as shown in the figure. As shown in FIG. 3, the electrode body 10 of the present invention presses the flat portion 6 thinner than the curved corner portion 7, and the filling density of the flat portion 6 is higher than that of the curved corner portion 7. 7 has a lower packing density than the flat portion 6. The curved corner portion 7 having a low filling density absorbs stress and elongation of the flat portion 6. In addition, the curved corner portion 7 having a low filling density also reduces the pressing force due to expansion. Therefore, the curved corner portion 7 acts as a buffer portion that absorbs the strain of the negative electrode 1B, and effectively prevents the deflection of the electrode plate 1.

電極体１０は、巻き取り体１１をプレスする圧力をコントロールして、負極１Ｂの充填密度を、平坦部６で高く、湾曲コーナー部７で低くする。プレス工程において、巻き取り体１１のプレス圧を強くして、平坦部６の充填密度を湾曲コーナー部７よりも高くできる。それは、平坦部６がプレスされて、湾曲コーナー部７がプレスされないからである。巻き取り体１１のプレス圧は、予備プレスされた負極１Ｂの充填密度を考慮して最適値に設定される。たとえば、プレス工程における巻き取り体１１のプレス圧を、０．７ＭＰａとして、充填密度を１．６ｇ／ｃｃとする負極１Ｂの活物質層５の充填密度を、平坦部６と湾曲コーナー部７とで２〜４％の差を設けることができる。プレス工程における巻き取り体１１の最適プレス圧は、巻き取り体１１を構成している極板１の充填密度が低い場合に低く、極板１の充填密度が高いときに高くする。   The electrode body 10 controls the pressure at which the winding body 11 is pressed to increase the filling density of the negative electrode 1B at the flat portion 6 and at the curved corner portion 7. In the pressing step, the press pressure of the wound body 11 can be increased to make the filling density of the flat portion 6 higher than that of the curved corner portion 7. This is because the flat portion 6 is pressed and the curved corner portion 7 is not pressed. The press pressure of the wound body 11 is set to an optimum value in consideration of the filling density of the negatively-pressed negative electrode 1B. For example, the pressing pressure of the winding body 11 in the pressing step is 0.7 MPa, the packing density of the active material layer 5 of the negative electrode 1B is 1.6 g / cc, and the flat portion 6 and the curved corner portion 7 A difference of 2 to 4% can be provided. The optimum pressing pressure of the winding body 11 in the pressing step is low when the packing density of the electrode plate 1 constituting the winding body 11 is low, and is increased when the packing density of the electrode plate 1 is high.

巻き取り体１１をプレスするプレス工程でプレスして製作される電極体１０は、平坦部６と巻き取り体１１との充填密度差を１％以上、好ましくは２％以上、さらに好ましくは３％以上とする。ただし、平坦部６と湾曲コーナー部７との充填密度の差が大きすぎる電極体１０は、プレス工程のプレス圧が高くなって、プレス工程でセパレータ３の目がつぶれ、これによって電池の放電性能が低下する。したがって、平坦部６と湾曲コーナー部７の充填密度の差は、７％よりも小さく、好ましくは５％よりも小さくする。   The electrode body 10 manufactured by pressing in the pressing step of pressing the wound body 11 has a filling density difference between the flat portion 6 and the wound body 11 of 1% or more, preferably 2% or more, more preferably 3%. That's it. However, in the electrode body 10 in which the difference in filling density between the flat portion 6 and the curved corner portion 7 is too large, the press pressure in the press process becomes high, and the eyes of the separator 3 are collapsed in the press process. Decreases. Therefore, the difference in filling density between the flat portion 6 and the curved corner portion 7 is smaller than 7%, preferably smaller than 5%.

電極体１０は、巻き取り体１１をプレスする圧力で平坦部６と湾曲コーナー部７の充填密度に差を設けている。この状態で充填密度に差ができる極板１は、平坦部６と湾曲コーナー部７の厚さにも差ができる。それは、平坦部６が湾曲コーナー部７よりも薄く押し潰されることで、平坦部６の充填密度を湾曲コーナー部７よりも大きくしているからである。極板１の充填密度と厚さは互いに反比例する関係にあり、充填密度が２倍になると、厚さは半分になる。したがって、極板１の充填密度を特定することは、実質的には極板１の厚さを特定するのと同じである。巻き取り体１１をプレスする工程で、湾曲コーナー部７よりも平坦部６を薄く押し潰して、平坦部６の充填密度を湾曲コーナー部７よりも高くできるからである。したがって、本発明の電池は、負極１Ｂの平坦部６と湾曲コーナー部７の充填密度を特定し、あるいは平坦部６と湾曲コーナー部７の厚さを特定している。電極体１０の負極１Ｂの平坦部６と湾曲コーナー部７の厚さの差は、充填密度の差と同じように、１％以上、好ましくは２％以上、さらに好ましくは３％以上とする。ただし、平坦部６と湾曲コーナー部７との厚さの差も大きすぎると、プレス工程でセパレータ３の目がつぶれて放電性能が低下するので、厚さの差は、７％よりも小さく、好ましくは５％よりも小さくする。   The electrode body 10 provides a difference in the packing density of the flat portion 6 and the curved corner portion 7 by the pressure with which the winding body 11 is pressed. In this state, the electrode plate 1 that can have a difference in packing density can also have a difference in thickness between the flat portion 6 and the curved corner portion 7. This is because the flat portion 6 is crushed thinner than the curved corner portion 7, thereby making the filling density of the flat portion 6 larger than that of the curved corner portion 7. The filling density and the thickness of the electrode plate 1 are inversely proportional to each other. When the filling density is doubled, the thickness is halved. Therefore, specifying the packing density of the electrode plate 1 is substantially the same as specifying the thickness of the electrode plate 1. This is because, in the step of pressing the winding body 11, the flat portion 6 is crushed thinner than the curved corner portion 7, and the filling density of the flat portion 6 can be made higher than that of the curved corner portion 7. Therefore, in the battery of the present invention, the filling density of the flat portion 6 and the curved corner portion 7 of the negative electrode 1B is specified, or the thickness of the flat portion 6 and the curved corner portion 7 is specified. The difference in thickness between the flat portion 6 and the curved corner portion 7 of the negative electrode 1B of the electrode body 10 is set to 1% or more, preferably 2% or more, and more preferably 3% or more, like the difference in filling density. However, if the difference in thickness between the flat portion 6 and the curved corner portion 7 is too large, the separator 3 is collapsed in the pressing process and the discharge performance is reduced, so the difference in thickness is smaller than 7%. Preferably it is smaller than 5%.

リチウムイオン二次電池の角型電池は以下のようにして製造される。
［正極スラリーの作製］
正極活物質として、平均粒径５μｍのＬｉＣｏＯ２粉末と、正極導電剤としての人造黒鉛粉末を、質量比９０：５で混合して、正極合剤を調製する。この正極合剤と、Ｎ−メチル−２−ピロリドン（ＮＭＰ）にポリフッ化ビニリデンを５質量％溶かした結着剤溶媒とを、固形分の質量比で９５：５となるように混練して正極活物質スラリーを調整する。 A square battery of a lithium ion secondary battery is manufactured as follows.
[Preparation of positive electrode slurry]
As a positive electrode active material, LiCoO 2 powder having an average particle diameter of 5 μm and artificial graphite powder as a positive electrode conductive agent are mixed at a mass ratio of 90: 5 to prepare a positive electrode mixture. This positive electrode mixture and a binder solvent obtained by dissolving 5% by mass of polyvinylidene fluoride in N-methyl-2-pyrrolidone (NMP) are kneaded so that the mass ratio of the solid content is 95: 5. Adjust the active material slurry.

［正極極板の作製］
このスラリーを、正極１Ａの芯体４としてアルミ箔（箔厚み：１０μｍ）にドクターブレードを用いて、合剤塗布量が４６０ｇ／ｍ２となるように塗布する。塗布した後、乾燥させてその極板を圧縮して、正極１Ａの極板を作製する。その後、極板を電池幅に合うように切断し、１２０℃に２時間で真空乾燥して、正極１Ａの極板とする。正極１Ａは、塗布量を一定として圧縮時の圧力で厚さをコントロールして充填密度を変化できる。この工程で、厚さを１４０μｍ、充填密度を３．６８ｇ／ｃｃとする正極１Ａの極板を得る。 [Preparation of positive electrode plate]
This slurry is applied to the aluminum foil (foil thickness: 10 μm) as the core body 4 of the positive electrode 1A using a doctor blade so that the mixture application amount is 460 g / m 2 . After the application, the electrode plate is dried and compressed to produce the electrode plate of the positive electrode 1A. Thereafter, the electrode plate is cut to fit the battery width and vacuum dried at 120 ° C. for 2 hours to obtain the electrode plate of the positive electrode 1A. The positive electrode 1A can change the packing density by controlling the thickness with the pressure at the time of compression while keeping the coating amount constant. In this step, an electrode plate of the positive electrode 1A having a thickness of 140 μm and a packing density of 3.68 g / cc is obtained.

［負極極板の作製］
球状天然黒鉛（ｄ００２値：０．３３５６ｎｍ、Ｌｃ値：１００ｎｍ、平均粒径：２０μｍ）をスチレン−ブタジエンゴム（ＳＢＲ）のディスパージョン（固形分：４８％）を水に分散させて、増粘剤であるカルボキシメチルセルロース（ＣＭＣ）を添加して負極スラリーを調製する。なお、この負極スラリーは、乾燥後の固形分質量組成比が、活物質：ＳＢＲ：ＣＭＣ＝９６：２： ２となるように調製する。
この負極スラリーを、負極１Ｂの芯体４としての銅箔（箔厚み：１０μｍ）の両面に、乾燥後質量で２００ｇ／ｍ２（片面塗布１００ｇ／ｍ２、集電体除く）となるよう塗布する。その後、乾燥させてその極板を加圧して圧縮し、活物質の充填密度を１．３５ｇ／ｃｃ〜１．６５ｇ／ｃｃとする負極１Ｂの極板とする。その後、極板を電池幅に合うように切断し、１１０℃、２時間で真空乾燥して負極１Ｂの極板を得る。 [Production of negative electrode plate]
Spherical natural graphite (d 002 value: 0.3356 nm, Lc value: 100 nm, average particle size: 20 μm) is dispersed in styrene-butadiene rubber (SBR) dispersion (solid content: 48%) in water to increase the viscosity. A negative electrode slurry is prepared by adding carboxymethyl cellulose (CMC) as an agent. In addition, this negative electrode slurry is prepared so that the solid content mass composition ratio after drying may be active material: SBR: CMC = 96: 2: 2.
This negative electrode slurry was applied on both sides of a copper foil (foil thickness: 10 μm) as the core 4 of the negative electrode 1B so that the mass after drying was 200 g / m 2 (100 g / m 2 on one side, excluding the current collector). To do. Then, it dries and presses and compresses the electrode plate, and it is set as the electrode plate of the negative electrode 1B which makes the packing density of an active material into 1.35 g / cc-1.65 g / cc. Thereafter, the electrode plate is cut to fit the battery width and vacuum dried at 110 ° C. for 2 hours to obtain the electrode plate of the negative electrode 1B.

［電解液とセパレータ］
非水電解液として、エチレンカーボネート（ＥＣ）とエチルメチルカーボネート（ＥＭＣ）を、体積比３／７の混合溶媒に、支持塩として六フッ化リン酸リチウム（ＬｉＰＦ６）を１モル／リットル濃度に溶かした溶液を使用する。また、セパレータ３としては、２０μｍのポリプロピレン製の微多孔膜を使用する。 [Electrolyte and separator]
As a non-aqueous electrolyte, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are used in a mixed solvent with a volume ratio of 3/7, and lithium hexafluorophosphate (LiPF 6 ) is used as a supporting salt at a concentration of 1 mol / liter. Use the dissolved solution. The separator 3 is a 20 μm polypropylene microporous membrane.

［電極体の作製］
以上のようにして得られた正極１Ａ及び負極１Ｂの極板１と、セパレータ３を渦巻状に捲回して巻き取り体１１とする。電極の巻き取り体１１を、プレス工程において０．７ＭＰａでプレスして電極体１０とする。このプレス工程において、電極体１０の負極１Ｂの平坦部６と湾曲コーナー部７の充填密度と厚さは表１の値として実施例１〜９の電極体１０を作製する。プレス工程において、電極体１０の負極１Ｂの湾曲コーナー部７はプレスされず、巻き取り体１１のときに同じ充填密度及び厚さとなる。 [Production of electrode body]
The electrode plate 1 of the positive electrode 1A and the negative electrode 1B obtained as described above and the separator 3 are wound in a spiral shape to form a wound body 11. The electrode winding body 11 is pressed at 0.7 MPa in the pressing step to obtain an electrode body 10. In this pressing step, the electrode bodies 10 of Examples 1 to 9 are manufactured with the packing density and thickness of the flat portion 6 and the curved corner portion 7 of the negative electrode 1B of the electrode body 10 as shown in Table 1. In the pressing step, the curved corner portion 7 of the negative electrode 1 </ b> B of the electrode body 10 is not pressed and has the same packing density and thickness when the wound body 11 is used.

Figure 2006278182
Figure 2006278182

［電池の作製］
以上の電極体１０を外装体である外装缶２０に挿入して角型電池とする。外装缶２０は、アルミニウム又はアルミニウム合金の金属ケースである。電極体１０を挿入した外装缶２０は、開口部に封口板２１を溶接して閉塞する。その後、封口板２１に設けた注液口から外装缶２０の内部に電解液を注液し、その後、注液口を気密に封止する。
以上の工程で、厚さ：５．０ｍｍまたは４．８ｍｍ、幅：３０ｍｍ、高さ：４８ｍｍ（設計容量：８２０ｍＡｈ）の角型電池を作製する。 [Production of battery]
The above electrode body 10 is inserted into an outer can 20 which is an outer body to obtain a square battery. The outer can 20 is a metal case made of aluminum or aluminum alloy. The outer can 20 into which the electrode body 10 is inserted is closed by welding a sealing plate 21 to the opening. Thereafter, the electrolytic solution is injected into the exterior can 20 from the injection port provided on the sealing plate 21, and then the injection port is hermetically sealed.
Through the above steps, a rectangular battery having a thickness of 5.0 mm or 4.8 mm, a width of 30 mm, and a height of 48 mm (design capacity: 820 mAh) is manufactured.

比較例Comparative example

実施例１〜９の電池の優れた特性を実証するために、比較例１〜６の角型電池を試作する。比較例の電池は、負極１Ｂの平坦部６と湾曲コーナー部７の充填密度と厚さを同じとする以外、実施例の角型電池と同じようにして製作する。   In order to demonstrate the excellent characteristics of the batteries of Examples 1 to 9, the square batteries of Comparative Examples 1 to 6 are prototyped. The battery of the comparative example is manufactured in the same manner as the prismatic battery of the example, except that the flat portion 6 and the curved corner portion 7 of the negative electrode 1B have the same filling density and thickness.

なお、実施例と比較例の角型電池は、以下の条件で充放電させて、表２に示す優れた特性を示す。
（１） 充放電サイクル条件：
温度：２３℃
充電：８２０ｍＡ（１Ｉｔ）４．２Ｖまで定電流充電、
４．２Ｖで１６ｍＡまで定電圧充電
放電：８２０ｍＡ（１Ｉｔ）で２．７５Ｖまで定電流放電 In addition, the square battery of an Example and a comparative example is charged / discharged on the following conditions, and shows the outstanding characteristic shown in Table 2.
(1) Charge / discharge cycle conditions:
Temperature: 23 ° C
Charging: constant current charging up to 820mA (1It) 4.2V,
4.2V constant voltage charge up to 16mA
Discharge: Constant current discharge to 2.75 V at 820 mA (1 It)

（２） 初期満充電電池厚み：
「充放電サイクル」の充電と同じ方法で充電後、ノギスを用いて電池厚み（広い面の中心部）を測定
※ 設計を適切にするため、負極１Ｂの湾曲コーナー部７における充填密度１.６以上では、缶厚みを４.８ｍｍ、１．６未満では５．０ｍｍとしている。 (2) Initial fully charged battery thickness:
After charging in the same way as the charge / discharge cycle, measure the battery thickness (center of the wide surface) using calipers. * To make the design appropriate, the packing density at the curved corner 7 of the negative electrode 1B is 1.6. In the above, the can thickness is 4.8 mm, and if it is less than 1.6, it is 5.0 mm.

（３） 結果
負極１Ｂの湾曲コーナー部７の厚みを１００としたときの平坦部６の厚みを表１に記載している。
負極１Ｂの平坦部６の厚さが、湾曲コーナー部７に対して９８．５％以下の場合に、初期の厚みと、５００サイクル後の容量維持率で効果が見られる。
たとえば、実施例１の電池は、比較例１の電池に比較して５００サイクル後の容量維持率が、４５％から８０％と著しく向上する。このことは、充放電において負極１Ｂのたわみが有効に防止された結果、反応の不均一による放電性能の低下が有効に防止されたことを実証する。
また、実施例２〜９の電池は、比較例２〜６の電池に比較して５００サイクル後の容量維持率が、５０％〜６５％から、７０％〜８５％と著しく向上する。 (3) Results Table 1 shows the thickness of the flat portion 6 when the thickness of the curved corner portion 7 of the negative electrode 1B is 100.
When the thickness of the flat portion 6 of the negative electrode 1B is 98.5% or less with respect to the curved corner portion 7, an effect is seen in the initial thickness and the capacity retention rate after 500 cycles.
For example, the capacity retention rate after 500 cycles of the battery of Example 1 is significantly improved from 45% to 80% as compared with the battery of Comparative Example 1. This demonstrates that, as a result of effectively preventing the deflection of the negative electrode 1B during charging and discharging, a reduction in discharge performance due to non-uniform reaction was effectively prevented.
Further, in the batteries of Examples 2 to 9, the capacity maintenance rate after 500 cycles is remarkably improved from 50% to 65% to 70% to 85% as compared with the batteries of Comparative Examples 2 to 6.

Figure 2006278182
Figure 2006278182

本発明の一実施例にかかる非水電解質二次電池の一部断面斜視図である。It is a partial cross section perspective view of the nonaqueous electrolyte secondary battery concerning one example of the present invention. 図１に示す非水電解質二次電池の電極体の中心部を示す拡大断面図である。It is an expanded sectional view which shows the center part of the electrode body of the nonaqueous electrolyte secondary battery shown in FIG. 本発明の一実施例にかかる非水電解質二次電池の電極体の製造状態を示す一部拡大概略断面図である。It is a partially expanded schematic sectional drawing which shows the manufacture state of the electrode body of the nonaqueous electrolyte secondary battery concerning one Example of this invention. 従来の非水電解質二次電池の電極体の製造状態を示す概略断面図である。It is a schematic sectional drawing which shows the manufacturing state of the electrode body of the conventional nonaqueous electrolyte secondary battery.

符号の説明Explanation of symbols

１…極板 １Ａ…正極
１Ｂ…負極
３…セパレータ
４…芯体
５…活物質層
６…平坦部
７…湾曲コーナー部
１０…電極体
１１…巻き取り体
２０…外装缶
２１…封口板 1 ... Electrode plate 1A ... Positive electrode
DESCRIPTION OF SYMBOLS 1B ... Negative electrode 3 ... Separator 4 ... Core body 5 ... Active material layer 6 ... Flat part 7 ... Curved corner part 10 ... Electrode body 11 ... Winding body 20 ... Exterior can 21 ... Sealing plate

Claims (8)

負極(1B)と正極(1A)とをセパレータ(3)を介して積層してなる電極体(10)を備え、この電極体(10)の極板(1)は、負極(1B)と正極(1A)を平面状として積層している平坦部(6)と、この平坦部(6)に連結されて所定の曲率半径で湾曲する状態で積層している湾曲コーナー部(7)とからなり、
負極(1B)は芯体(4)に活物質層(5)を付着しており、かつ負極(1B)の活物質層(5)は、湾曲コーナー部(7)の充填密度を、平坦部(6)の充填密度よりも小さくしていることを特徴とする非水電解質二次電池。 An electrode body (10) is formed by laminating a negative electrode (1B) and a positive electrode (1A) with a separator (3) interposed therebetween, and an electrode plate (1) of the electrode body (10) includes a negative electrode (1B) and a positive electrode (1A) comprises a flat portion (6) laminated in a planar shape, and a curved corner portion (7) connected to the flat portion (6) and laminated in a state of being bent at a predetermined radius of curvature. ,
The negative electrode (1B) has an active material layer (5) attached to the core body (4), and the active material layer (5) of the negative electrode (1B) has a flat portion with a packing density of the curved corner portion (7). A non-aqueous electrolyte secondary battery characterized by being smaller than the packing density of (6). 負極(1B)と正極(1A)とをセパレータ(3)を介して積層してなる電極体(10)を備え、この電極体(10)の極板(1)は、負極(1B)と正極(1A)を平面状として積層している平坦部(6)と、この平坦部(6)に連結されて所定の曲率半径で湾曲する状態で積層している湾曲コーナー部(7)とからなり、
負極(1B)は芯体(4)に活物質層(5)を付着しており、かつ負極(1B)の活物質層(5)は、平坦部(6)の厚さよりも湾曲コーナー部(7)を厚くしてなることを特徴とする非水電解質二次電池。 An electrode body (10) is formed by laminating a negative electrode (1B) and a positive electrode (1A) with a separator (3) interposed therebetween, and an electrode plate (1) of the electrode body (10) includes a negative electrode (1B) and a positive electrode (1A) comprises a flat portion (6) laminated in a planar shape, and a curved corner portion (7) connected to the flat portion (6) and laminated in a state of being bent at a predetermined radius of curvature. ,
The negative electrode (1B) has an active material layer (5) attached to the core body (4), and the active material layer (5) of the negative electrode (1B) has a curved corner portion (more than the thickness of the flat portion (6) ( 7) A non-aqueous electrolyte secondary battery characterized by being thickened. 負極(1B)と正極(1A)とをセパレータ(3)を介して積層してなる電極体(10)を備え、この電極体(10)の極板１は、負極(1B)と正極(1A)を平面状として積層している平坦部(6)と、この平坦部(6)に連結されて所定の曲率半径で湾曲する状態で積層している湾曲コーナー部(7)とからなり、
負極(1B)は芯体(4)に活物質層(5)を付着しており、かつ負極(1B)の活物質層(5)は、湾曲コーナー部(7)の充填密度を、平坦部(6)の充填密度よりも小さくすると共に、負極(1B)の活物質層(5)の厚さは、平坦部(6)よりも湾曲コーナー部(7)を厚くしてなることを特徴とする非水電解質二次電池。 An electrode body (10) is formed by laminating a negative electrode (1B) and a positive electrode (1A) with a separator (3) interposed therebetween. An electrode plate 1 of the electrode body (10) includes a negative electrode (1B) and a positive electrode (1A ) And a flat corner (6) laminated in a flat shape, and a curved corner portion (7) laminated in a state of being curved with a predetermined curvature radius connected to the flat portion (6),
The negative electrode (1B) has an active material layer (5) attached to the core body (4), and the active material layer (5) of the negative electrode (1B) has a flat portion with a packing density of the curved corner portion (7). The thickness of the active material layer (5) of the negative electrode (1B) is smaller than the packing density of (6), and the curved corner portion (7) is thicker than the flat portion (6). Non-aqueous electrolyte secondary battery. 負極(1B)が、湾曲コーナー部(7)と平坦部(6)の充填密度の差を１％以上としている請求項１又は３に記載される非水電解質二次電池。   The nonaqueous electrolyte secondary battery according to claim 1 or 3, wherein the negative electrode (1B) has a difference in packing density of the curved corner portion (7) and the flat portion (6) of 1% or more. 負極(1B)が、湾曲コーナー部(7)と平坦部(6)の厚さの差を１％以上としている請求項２又は３に記載される非水電解質二次電池。   The nonaqueous electrolyte secondary battery according to claim 2 or 3, wherein the negative electrode (1B) has a thickness difference of 1% or more between the curved corner portion (7) and the flat portion (6). 活物質層(5)の充填密度が１．４０ｇ／ｃｃ以上である請求項１ないし５のいずれかに記載される非水電解質二次電池。   The nonaqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein a packing density of the active material layer (5) is 1.40 g / cc or more. 負極(1B)と正極(1A)とをセパレータ(3)を介して積層して渦巻状に巻く巻き工程と、
巻き工程で得られた電極の巻き取り体(11)を、両面からプレスして、極板(1)を平坦部(6)と湾曲コーナー部(7)とするプレス工程と、
プレス工程で得られた電極体(10)を外装缶(20)に入れて、外装缶(20)の開口部を閉塞する組立工程とからなる非水電解質二次電池の製造方法であって、
プレス工程において、負極(1B)の湾曲コーナー部(7)における活物質層(5)の充填密度を、平坦部(6)の活物質層(5)の充填密度よりも小さくすると共に、湾曲コーナー部(7)と平坦部(6)の充填密度の差が１％以上となるようにプレスすることを特徴とする非水電解質二次電池の製造方法。 A winding step of laminating the negative electrode (1B) and the positive electrode (1A) via a separator (3) and winding them in a spiral shape;
The electrode winding body (11) obtained in the winding step is pressed from both sides, and the electrode plate (1) is a flat portion (6) and a curved corner portion (7), and a pressing step;
An electrode body (10) obtained in the pressing step is put into an outer can (20), and is a method for producing a nonaqueous electrolyte secondary battery comprising an assembly step of closing an opening of the outer can (20),
In the pressing step, the filling density of the active material layer (5) in the curved corner portion (7) of the negative electrode (1B) is made smaller than the packing density of the active material layer (5) of the flat portion (6), and the curved corner portion A method for producing a non-aqueous electrolyte secondary battery, comprising pressing so that a difference in packing density between the portion (7) and the flat portion (6) is 1% or more. 負極(1B)と正極(1A)とをセパレータ(3)を介して積層して渦巻状に巻く巻き工程と、
巻き工程で得られた電極の巻き取り体(11)を、両面からプレスして、極板(1)を平坦部(6)と湾曲コーナー部(7)とするプレス工程と、
プレス工程で得られた電極体(10)を外装缶(20)に入れて、外装缶(20)の開口部を閉塞する組立工程とからなる非水電解質二次電池の製造方法であって、
プレス工程において、負極(1B)の湾曲コーナー部(7)の活物質層(5)の厚さを、平坦部(6)の活物質層(5)よりも厚くすると共に、湾曲コーナー部(7)と平坦部(6)の厚さの差を１％以上とするようにプレスすることを特徴とする非水電解質二次電池の製造方法。
A winding step of laminating the negative electrode (1B) and the positive electrode (1A) via a separator (3) and winding them in a spiral shape;
The electrode winding body (11) obtained in the winding step is pressed from both sides, and the electrode plate (1) is a flat portion (6) and a curved corner portion (7), and a pressing step;
An electrode body (10) obtained in the pressing step is put into an outer can (20), and is a method for producing a nonaqueous electrolyte secondary battery comprising an assembly step of closing an opening of the outer can (20),
In the pressing step, the thickness of the active material layer (5) of the curved corner portion (7) of the negative electrode (1B) is made thicker than the active material layer (5) of the flat portion (6), and the curved corner portion (7 ) And the flat portion (6) are pressed so that the difference in thickness is 1% or more. A method for producing a non-aqueous electrolyte secondary battery.
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WO2022067789A1 (en) * 2020-09-30 2022-04-07 宁德新能源科技有限公司 Electrode assembly, battery, and electronic device
CN113381080B (en) * 2021-06-15 2022-06-10 广东国光电子有限公司 Manufacturing method of battery roll core and battery roll core
CN113381080A (en) * 2021-06-15 2021-09-10 广东国光电子有限公司 Manufacturing method of battery roll core and battery roll core
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CN114784230B (en) * 2022-03-29 2023-12-12 东莞锂威能源科技有限公司 Method for improving lithium precipitation of soft-package square battery
CN114784364A (en) * 2022-03-31 2022-07-22 宁德新能源科技有限公司 Electrochemical device and electronic device
WO2023212867A1 (en) * 2022-05-05 2023-11-09 宁德时代新能源科技股份有限公司 Positive electrode plate, electrode assembly, battery cell, battery, and electrical device

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