JP5779562B2

JP5779562B2 - Square battery

Info

Publication number: JP5779562B2
Application number: JP2012206316A
Authority: JP
Inventors: 稔之有賀; 渡辺　聡; 聡渡辺; 佳佑澤田
Original assignee: Hitachi Automotive Systems Ltd
Current assignee: Hitachi Astemo Ltd
Priority date: 2012-09-19
Filing date: 2012-09-19
Publication date: 2015-09-16
Anticipated expiration: 2032-09-19
Also published as: JP2014063569A

Description

本発明は、例えば車両等に使用されるリチウムイオン二次電池などの角形電池に関する。 The present invention relates to a prismatic battery such as a lithium ion secondary battery used in, for example, a vehicle.

従来から、円筒型電池に比較してより高い体積密度が得られる電池として、角形電池が知られている。角形電池は、角形の電池容器に、発電要素である偏平の捲回電極体を収容している。捲回電極体は、正極板と負極板を、間にセパレータを介して絶縁された状態で重ねて捲回することによって構成されている。捲回電極体の捲回軸方向一方側には、正極未塗工部が束ねられた正極集電体積層部が設けられ、捲回軸方向他方側には、負極未塗工部が束ねられた負極集電体積層部が設けられており、正極集電体積層部には正極接続端子が接合され、また、負極集電体積層部には負極接続端子が接合されている。正極接続端子および負極接続端子は、例えば電池容器の外側で電池蓋などの電池容器の同一面上に配置された正極外部端子および負極外部端子にそれぞれ導通接続されており、電池容器が電気的に中立から成る構造、すなわち、電池容器が捲回電極体から絶縁された構造を有している。 Conventionally, a prismatic battery is known as a battery that can obtain a higher volume density than a cylindrical battery. In the rectangular battery, a flat wound electrode body as a power generation element is accommodated in a rectangular battery container. The wound electrode body is configured by winding a positive electrode plate and a negative electrode plate in a state of being insulated with a separator interposed therebetween. A positive electrode current collector laminated portion in which positive electrode uncoated portions are bundled is provided on one side in the winding axis direction of the wound electrode body, and a negative electrode uncoated portion is bundled on the other side in the winding axis direction. In addition, a negative electrode current collector laminate is provided, and a positive electrode connection terminal is joined to the positive electrode current collector laminate, and a negative electrode connection terminal is joined to the negative electrode current collector laminate. The positive electrode connection terminal and the negative electrode connection terminal are electrically connected to, for example, the positive electrode external terminal and the negative electrode external terminal arranged on the same surface of the battery container such as a battery lid on the outside of the battery container. The structure is neutral, that is, the battery container is insulated from the wound electrode body.

この種の角形電池において、電池内部に位置する捲回電極体の正極集電体積層部、負極集電体積層部、及びこれらに接続される正極接続端子、負極接続端子が、電池容器の内壁を通じて短絡しないようにするために、また、捲回電極体を電池容器に挿入する際に捲回電極体の表面に傷がつかないようにするために、捲回電極体と電池容器の内壁との間に絶縁性の保護シートないしフィルムを介在させて保護しているものが種々提案されている。 In this type of prismatic battery, the positive electrode current collector laminated portion, the negative electrode current collector laminated portion of the wound electrode body located inside the battery, and the positive electrode connecting terminal and the negative electrode connecting terminal connected to these are the inner wall of the battery container. In order to prevent a short circuit through the wound electrode body and to prevent the wound electrode body from being scratched when inserted into the battery container, the wound electrode body and the inner wall of the battery container Various materials have been proposed which are protected by interposing an insulating protective sheet or film between them.

たとえば、絶縁材シートが、捲回電極体の扁平面に対向する一対の幅広面を形成する一対の幅広面形成部と、その一対の幅広面形成部の間に存在する部分であって電池ケースの底面に対向する底面を形成する底面形成部と、上記一対の幅広面形成部の両側にそれぞれ存在する部分であって電池ケースの幅広面間の狭側面を形成する二対の狭側面形成部とを有しており、袋状に折り曲げられた内側に配置される狭側面形成部が、外側に配置される狭側面形成部よりも小さく形成されており、電池外装缶に挿入が容易になるように工夫されたものが知られている（例えば特許文献１を参照）。 For example, the battery case is a portion in which the insulating material sheet exists between a pair of wide surface forming portions that form a pair of wide surfaces facing the flat surface of the wound electrode body and the pair of wide surface forming portions. A bottom surface forming portion that forms a bottom surface that faces the bottom surface of the battery, and two pairs of narrow side surface forming portions that are respectively present on both sides of the pair of wide surface forming portions and form a narrow side surface between the wide surfaces of the battery case And the narrow side surface forming portion disposed on the inner side folded into a bag shape is formed smaller than the narrow side surface forming portion disposed on the outer side, and can be easily inserted into the battery outer can. Such a device is known (for example, see Patent Document 1).

特開２０１０−２８７４５６号公報JP 2010-287456 A

しかしながら、特許文献１に示される二次電池は、絶縁性のシートを複雑に折り曲げて箱状に形成し、その中に捲回電極体を収容して外装缶に収納する構造をしている。このように箱状の絶縁性シートの場合、（１）シートを折り曲げ、（２）捲回電極体を収容し、（３）位置がずれないように外装缶に挿入する、という工程が必要となる。特にシートの折り曲げでは、自動化が困難であり、かつ生産性に欠けるといった問題がある。 However, the secondary battery disclosed in Patent Document 1 has a structure in which an insulating sheet is folded in a complicated manner to form a box shape, and a wound electrode body is accommodated therein and accommodated in an outer can. Thus, in the case of a box-like insulating sheet, the steps of (1) folding the sheet, (2) accommodating the wound electrode body, and (3) inserting the wound can into the outer can so that the position does not shift are necessary. Become. In particular, when folding a sheet, there are problems that automation is difficult and productivity is lacking.

本発明は、上記従来の問題点に鑑みてなされたものであり、その目的とするところは、電池容器と発電要素との間に絶縁部材を簡単に介在させることができ、絶縁部材の装着作業の自動化が容易であり、生産性に優れた構造を有する角形電池とその製造方法を提供することである。 The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to allow an insulating member to be easily interposed between the battery container and the power generation element, and to install the insulating member. It is an object of the present invention to provide a prismatic battery having a structure that is easy to automate and excellent in productivity, and a manufacturing method thereof.

上記課題を解決する本発明のリチウムイオン二次電池は、電極板を捲回して形成された扁平状の捲回電極体と、該捲回電極体の捲回軸方向が横向きで且つ前記捲回電極体の一対の湾曲部が上下に分かれて配置される姿勢状態の前記捲回電極体を収容し、前記捲回電極体を挿入可能な開口部が上部に設けられた有底の電池缶と、該電池缶と前記捲回電極体との間に介在される絶縁保護フィルムと、を有する角形電池であって、前記絶縁保護フィルムは、前記捲回電極体の扁平面に沿う方向でかつ前記捲回電極体の捲回軸方向に直交する方向を中心軸方向として前記捲回電極体の周囲に１周以上巻き付けられて前記捲回電極体の側面を覆う側面カバー部と、該側面カバー部から突出して前記捲回電極体の下側の湾曲部を覆う底面カバー部と、該底面カバー部から突出して前記捲回電極体の側面と前記電池缶の縦壁部との間に介在される折り返し片部と、を有することを特徴としている。 The lithium ion secondary battery of the present invention that solves the above problems includes a flat wound electrode body formed by winding an electrode plate, the winding axis direction of the wound electrode body being lateral, and the wound A bottomed battery can that accommodates the wound electrode body in a posture in which a pair of curved portions of the electrode body are arranged separately on the upper and lower sides, and an opening into which the wound electrode body can be inserted; An insulating protective film interposed between the battery can and the wound electrode body, wherein the insulating protective film is in a direction along a flat surface of the wound electrode body and the A side cover portion wound around the wound electrode body at least once around a direction orthogonal to the winding axis direction of the wound electrode body as a central axis direction and covering the side surface of the wound electrode body; and the side cover portion A bottom cover portion protruding from the wound electrode body and covering the lower curved portion of the wound electrode body, and the bottom Is characterized by having projecting from the cover portion the winding said the side surface of the electrode body, and a folded piece portion interposed between the vertical wall portion of the battery can.

本発明によれば、従来のように絶縁部材を複雑に折り曲げて発電要素を収納する必要がなく、容易に電池容器との絶縁の確保および発電要素の保護を可能し、生産性の向上を図ることができる。なお、上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。 According to the present invention, it is not necessary to bend the insulating member in a complicated manner as in the prior art to house the power generation element, and it is possible to easily ensure insulation from the battery container and protect the power generation element, thereby improving productivity. be able to. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

第１実施の形態に係わる角形電池の外観斜視図。The external appearance perspective view of the square battery concerning 1st Embodiment. 図１に示される角形電池の分解斜視図。The disassembled perspective view of the square battery shown by FIG. 図２に示された捲回電極体の詳細を示し、一部を展開した状態の外観斜視図。The external appearance perspective view of the state which showed the detail of the winding electrode body shown by FIG. 2, and developed a part. 絶縁保護フィルムの展開図。The development view of an insulating protective film. 絶縁保護フィルムと発電要素組立体の位置関係を説明する斜視図。The perspective view explaining the positional relationship of an insulation protective film and a power generation element assembly. 絶縁保護フィルムで捲回電極体の側面を覆った状態を示す斜視図。The perspective view which shows the state which covered the side surface of the winding electrode body with the insulation protective film. 絶縁保護フィルムで捲回電極体の底面を覆った状態を示す斜視図。The perspective view which shows the state which covered the bottom face of the winding electrode body with the insulating protective film. 絶縁保護フィルムに覆われた発電要素組立体を電池缶に挿入する状態を示す図。The figure which shows the state which inserts the electric power generation element assembly covered with the insulation protective film into a battery can. 図１の縦断面図。The longitudinal cross-sectional view of FIG. 第２実施の形態に係わる絶縁保護フィルムの展開図。The expanded view of the insulation protective film concerning 2nd Embodiment. 絶縁保護フィルムと発電要素組立体の位置関係を説明する斜視図。The perspective view explaining the positional relationship of an insulation protective film and a power generation element assembly. 絶縁保護フィルムで捲回電極体の側面を覆った状態を示す斜視図。The perspective view which shows the state which covered the side surface of the winding electrode body with the insulation protective film. 絶縁保護フィルムで捲回電極体の底面を覆った状態を示す斜視図。The perspective view which shows the state which covered the bottom face of the winding electrode body with the insulating protective film. 絶縁保護フィルムに覆われた発電要素組立体を電池缶に挿入する状態を示す図。The figure which shows the state which inserts the electric power generation element assembly covered with the insulation protective film into a battery can.

次に、本発明の実施形態について説明する。 Next, an embodiment of the present invention will be described.

以下の実施形態では、角形電池の一例として、ハイブリッド自動車や電気自動車で使用されるリチウムイオン二次電池の場合について説明する。 In the following embodiments, a case of a lithium ion secondary battery used in a hybrid vehicle or an electric vehicle will be described as an example of a square battery.

＜第１実施の形態＞
図１は、第１実施の形態に係わる角形電池の外観斜視図、図２は、図１に示される角形電池の分解斜視図である。 <First embodiment>
FIG. 1 is an external perspective view of the prismatic battery according to the first embodiment, and FIG. 2 is an exploded perspective view of the prismatic battery shown in FIG.

角形電池であるリチウムイオン二次電池１は、図１及び図２に示すように、電池容器２内に発電要素３を収容した構成を有している。電池容器２は、上部に開口部１１ａを有する有底の電池缶１１と、電池缶１１の開口部１１ａを封口する電池蓋２１とを有する。発電要素３は、正極板と負極板との間にセパレータを介在させて重ね合わせた状態で扁平状に捲回した捲回電極体３１を有している。捲回電極体３１は、その周りに、シート状の絶縁保護フィルム４１が巻き付けられた状態で電池容器２に収容されている。 As shown in FIGS. 1 and 2, the lithium ion secondary battery 1 that is a prismatic battery has a configuration in which a power generation element 3 is accommodated in a battery container 2. The battery container 2 includes a bottomed battery can 11 having an opening 11 a at the top, and a battery lid 21 that seals the opening 11 a of the battery can 11. The power generating element 3 has a wound electrode body 31 wound in a flat shape in a state where a separator is interposed between the positive electrode plate and the negative electrode plate and stacked. The wound electrode body 31 is accommodated in the battery container 2 in a state in which a sheet-like insulating protective film 41 is wound around the wound electrode body 31.

電池缶１１及び電池蓋２１は、共にアルミニウム合金で製作されており、電池蓋２１は、レーザ溶接によって電池缶１１に溶接される。電池容器２は、一対の幅広側面ＰＷと、一対の幅狭側面ＰＮと、底面ＰＢと、電池蓋２１とで直方体形状の扁平角形容器を構成する。電池蓋２１には、絶縁部材を介して正極端子５１と負極端子６１（一対の電極端子）が配設されており、蓋組立体４を構成している。なお、電池蓋２１には、正極端子５１及び負極端子６１の他に、電池容器２内の圧力が所定値よりも上昇すると開放されて電池容器２内のガスを排出するガス排出弁７１と、電池容器２内に電解液を注入するための注液口７２が配置されている。 The battery can 11 and the battery lid 21 are both made of an aluminum alloy, and the battery lid 21 is welded to the battery can 11 by laser welding. The battery container 2 includes a pair of wide side surfaces PW, a pair of narrow side surfaces PN, a bottom surface PB, and a battery lid 21 to form a rectangular parallelepiped flat rectangular container. The battery lid 21 is provided with a positive electrode terminal 51 and a negative electrode terminal 61 (a pair of electrode terminals) via an insulating member, and constitutes the lid assembly 4. In addition to the positive electrode terminal 51 and the negative electrode terminal 61, the battery lid 21 has a gas discharge valve 71 that is opened when the pressure in the battery container 2 rises above a predetermined value and discharges the gas in the battery container 2; A liquid injection port 72 for injecting an electrolytic solution into the battery container 2 is disposed.

正極端子５１及び負極端子６１は、電池蓋２１の長手方向一方側と他方側の互いに離れた位置に配置されている。正極端子５１及び負極端子６１は、電池蓋２１の外側に配置される外部端子５２、６２と、電池蓋２１の内側に配置されて外部端子５２、６２に導通接続される接続端子５３、６３を有している。正極側の外部端子５２と接続端子５３は、アルミニウム合金で製作され、負極側の外部端子６２と接続端子６３は、銅合金で製作されている。 The positive electrode terminal 51 and the negative electrode terminal 61 are disposed at positions separated from each other on one side and the other side in the longitudinal direction of the battery lid 21. The positive terminal 51 and the negative terminal 61 include external terminals 52 and 62 arranged outside the battery lid 21 and connection terminals 53 and 63 arranged inside the battery lid 21 and electrically connected to the external terminals 52 and 62. Have. The positive external terminal 52 and the connection terminal 53 are made of an aluminum alloy, and the negative external terminal 62 and the connection terminal 63 are made of a copper alloy.

接続端子５３、６３と外部端子５２、６２は、それぞれ電池蓋２１との間に図示していない絶縁部材が介在されており、電池蓋２１から電気的に絶縁されている。接続端子５３、６３は、電池蓋２１の内側から電池缶１１の底部に向かって延出して捲回電極体３１に導通接続される集電端子５４、６４を有している。捲回電極体３１は、正極端子５１の集電端子５４と負極端子６１の集電端子６４との間に配置されて支持されており、蓋組立体４及び捲回電極体３１によって、発電要素組立体５が構成されている。 Insulating members (not shown) are interposed between the connection terminals 53 and 63 and the external terminals 52 and 62, respectively, and are electrically insulated from the battery lid 21. The connection terminals 53 and 63 have current collection terminals 54 and 64 that extend from the inside of the battery lid 21 toward the bottom of the battery can 11 and are conductively connected to the wound electrode body 31. The wound electrode body 31 is disposed and supported between the current collecting terminal 54 of the positive electrode terminal 51 and the current collecting terminal 64 of the negative electrode terminal 61, and the power generation element is formed by the lid assembly 4 and the wound electrode body 31. An assembly 5 is configured.

発電要素組立体５では、捲回電極体３１の捲回軸方向が電池蓋２１に平行でかつ扁平面が電池蓋２１の下面に直交する方向に沿って延在し、捲回電極体３１の一方の湾曲部が電池蓋２１に対向して、他方の湾曲部が電池蓋２１から離反する方向に突出するように捲回電極体３１が支持されている。絶縁保護フィルム４１は、捲回電極体３１を集電端子５４、６４と共に、その外側から覆っており、電池缶１１の幅広側面ＰＷ、幅狭側面ＰＮ、底面ＰＢとの間にそれぞれ介在される。なお、絶縁保護フィルム４１の構成及び作用効果については、後で詳細に説明する。 In the power generation element assembly 5, the winding axis direction of the wound electrode body 31 extends in a direction parallel to the battery lid 21 and the flat surface is perpendicular to the lower surface of the battery lid 21. The wound electrode body 31 is supported such that one curved portion faces the battery lid 21 and the other curved portion protrudes in a direction away from the battery lid 21. The insulating protective film 41 covers the wound electrode body 31 together with the current collecting terminals 54 and 64 from the outside, and is interposed between the wide side surface PW, the narrow side surface PN, and the bottom surface PB of the battery can 11, respectively. . In addition, the structure and effect of the insulating protective film 41 will be described later in detail.

発電要素組立体５は、図２に示すように、電池缶１１の上方から接近させて、捲回電極体３１の下側の湾曲部（他方の湾曲部）を開口部１１ａに挿入し、電池蓋２１で電池缶１１の開口部１１ａを閉塞する。捲回電極体３１は、捲回軸方向が電池缶１１の開口部１１ａと平行となり、捲回軸方向が横向きで且つ捲回電極体の一対の湾曲部が上下に分かれて配置される姿勢状態で電池缶１１内に収容される。 As shown in FIG. 2, the power generating element assembly 5 is approached from above the battery can 11, and the lower curved portion (the other curved portion) of the wound electrode body 31 is inserted into the opening 11 a. The opening 21 a of the battery can 11 is closed with the lid 21. The wound electrode body 31 is in a posture state in which the winding axis direction is parallel to the opening 11a of the battery can 11, the winding axis direction is lateral, and the pair of curved portions of the wound electrode body are vertically divided. In the battery can 11.

電池缶１１は、捲回電極体３１の周囲を絶縁保護フィルム４１で覆った状態で開口部１１ａから電池缶１１に捲回電極体３１を挿入した場合に、捲回電極体３１の扁平面と電池缶１１の幅広側面ＰＷとが間に絶縁保護フィルム４１を挟み込んだ状態で当接し、若干の押圧力で押圧することによって挿入することができる寸法形状を有しており、捲回電極体３１の捲回軸方向両側の端面と電池缶１１の幅狭側面ＰＮとの間には、若干の間隙が形成されるようになっている。 When the wound electrode body 31 is inserted into the battery can 11 from the opening 11a in a state where the periphery of the wound electrode body 31 is covered with the insulating protective film 41, the battery can 11 and the flat surface of the wound electrode body 31 The battery can 11 is in contact with the wide side surface PW of the battery can 11 with the insulating protective film 41 sandwiched therebetween, and has a size and shape that can be inserted by pressing with a slight pressing force. A slight gap is formed between the end surfaces on both sides in the winding axis direction and the narrow side surface PN of the battery can 11.

電池容器２内には、電解液が充填されている。電解液は、電池蓋２１の注液口７２から電池容器２内に注入される。注液口７２は、電解液の注入後に、注液栓７３によって閉塞され、注液栓７３を電池蓋２１にレーザ溶接することによって封止される。 The battery container 2 is filled with an electrolytic solution. The electrolytic solution is injected into the battery container 2 from the liquid injection port 72 of the battery lid 21. The liquid injection port 72 is closed by a liquid injection plug 73 after the injection of the electrolytic solution, and is sealed by laser welding the liquid injection plug 73 to the battery lid 21.

電解液は、例えば、エチレンカーボネート（ＥＣ）とジメチルカーボネート（ＤＭＣ）とジエチルカーボネート（DEC）の体積比１：１：１の混合溶液中にＬｉＰＦ_６（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解したものを用いる。 The electrolyte is, for example, 1 mol / L of LiPF ₆ (lithium hexafluorophosphate) in a mixed solution of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) in a volume ratio of 1: 1: 1. What was melt | dissolved so that it might become.

尚、電解質は、ＬｉＰＦ_６を使用した例を示したが、これに限定されるものではなく、例えば、ＬｉＣｌＯ_４、ＬｉＡｓＦ_６、ＬｉＢＦ_４、ＬｉＢ（Ｃ_６Ｈ_５）_４、ＣＨ_３ＳＯ_３Ｌｉ、ＣＦ_３ＳＯＬｉなどやこれらの混合物を用いることができる。また、本実施形態では、非水電解液の溶媒にＥＣとＤＭＣとの混合溶媒を用いた例を示したが、プロピレンカーボネート、エチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、１，２−ジメトキシエタン、１，２−ジエトキシエタン、γ―ブチルラクトン、テトラヒドロフラン、１，３−ジオキソラン、４−メチル−１，３−ジオキソラン、ジエチルエーテル、スルホラン、メチルスルホラン、アセトニトリル、プロピオニトリル、プロピオニトリルなど少なくとも１種以上の混合溶媒を用いるようにしてもよく、また混合配合比についても限定されるものではない。 Incidentally, the electrolyte, an example of using LiPF _6, is not limited thereto, for _{_{_{example, LiClO 4, LiAsF 6, LiBF}}} 4, LiB (C 6 H 5) 4, CH 3 SO 3 Li , CF ₃ SOLi, or a mixture thereof can be used. Moreover, in this embodiment, although the example which used the mixed solvent of EC and DMC was shown as the solvent of nonaqueous electrolyte solution, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, 1, 2- dimethoxyethane, , 2-diethoxyethane, γ-butyllactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, propionitrile, etc. A mixed solvent of seeds or more may be used, and the mixing ratio is not limited.

図３は、図２に示された捲回電極体の詳細を示し、一部を展開した状態の外観斜視図である。 FIG. 3 is an external perspective view showing the details of the wound electrode body shown in FIG.

捲回電極体３１は、負極板３２、セパレータ３３、正極板３４、セパレータ３５の順に重ねて扁平状に捲回することによって構成される。捲回電極体３１は、図３に示すように、最外周の電極板が負極板３２であり、さらにその外側にセパレータ３５が捲回される。そして、セパレータ３５の捲き終わり端部が、図示していない粘着テープによってセパレータ３５の最外周面に固定されて、捲回状態を保持している。なお、セパレータ３５の捲き終わり端部は、捲回電極体３１の一方の扁平面上の略中央位置に配置されており、捲回軸方向中央部分が粘着テープ（図示せず）により固定されている。 The wound electrode body 31 is configured by winding a negative electrode plate 32, a separator 33, a positive electrode plate 34, and a separator 35 in this order and winding them in a flat shape. As shown in FIG. 3, in the wound electrode body 31, the outermost electrode plate is the negative electrode plate 32, and the separator 35 is wound further outside. The end of the separator 35 is fixed to the outermost peripheral surface of the separator 35 with an adhesive tape (not shown) to keep the wound state. In addition, the winding end end portion of the separator 35 is disposed at a substantially central position on one flat surface of the wound electrode body 31, and the central portion in the winding axis direction is fixed by an adhesive tape (not shown). Yes.

セパレータ３３、３５は、正極板３４と負極板３２を絶縁する役割を有している。負極板３２の負極塗工部３２ａは、正極板３４の正極塗工部３４ａよりも幅方向（図３のＸ方向に沿う方向）に大きく、これにより、正極塗工部３４ａは、必ず負極塗工部３２ａに挟まれるように構成されている。 The separators 33 and 35 have a role of insulating the positive electrode plate 34 and the negative electrode plate 32. The negative electrode coating portion 32a of the negative electrode plate 32 is larger in the width direction (the direction along the X direction in FIG. 3) than the positive electrode coating portion 34a of the positive electrode plate 34. It is comprised so that it may be pinched | interposed into the process part 32a.

正極未塗工部３４ｂ、負極未塗工部３２ｂは、平面部分で束ねられて溶接等により外部端子５２、６２につながる各極の集電端子５４、６４に接続される。尚、セパレータ３３、３５は、幅方向で負極塗工部３２ａよりも広いが、正極未塗工部３４ｂ、負極未塗工部３２ｂで金属箔面が露出する位置に捲回されるため、束ねて溶接する場合の支障にはならない。 The positive electrode uncoated portion 34b and the negative electrode uncoated portion 32b are bundled at a plane portion and connected to current collecting terminals 54 and 64 connected to the external terminals 52 and 62 by welding or the like. The separators 33 and 35 are wider than the negative electrode coated portion 32a in the width direction. However, the separators 33 and 35 are wound in positions where the metal foil surface is exposed at the positive electrode uncoated portion 34b and the negative electrode uncoated portion 32b. This will not interfere with welding.

正極板３４は、正極集電体である正極電極箔の両面に正極活物質合剤を塗布した正極塗工部３４ａを有し、正極電極箔の幅方向一方側の端部には、正極活物質合剤を塗布しない正極未塗工部（箔露出部）３４ｂが設けられている。 The positive electrode plate 34 has a positive electrode coating part 34a in which a positive electrode active material mixture is applied to both surfaces of a positive electrode foil that is a positive electrode current collector, and a positive electrode active part 34 is disposed at one end in the width direction of the positive electrode foil. A positive electrode uncoated part (foil exposed part) 34b where no material mixture is applied is provided.

負極板３２は、負極集電体である負極電極箔の両面に負極活物質合剤を塗布した負極塗工部３２ａを有し、正極電極箔の幅方向他方側の端部には、負極活物質合剤を塗布しない負極未塗工部（箔露出部）３２ｂが設けられている。正極未塗工部３４ｂと負極未塗工部３２ｂは、電極箔の金属面が露出した領域であり、図３に示すように、捲回軸方向一方側と他方側の位置に配置されるように捲回される。 The negative electrode plate 32 has a negative electrode coating part 32a in which a negative electrode active material mixture is applied to both surfaces of a negative electrode electrode foil that is a negative electrode current collector, and a negative electrode active part is provided at the other end in the width direction of the positive electrode foil. A negative electrode uncoated portion (foil exposed portion) 32b to which no material mixture is applied is provided. The positive electrode uncoated portion 34b and the negative electrode uncoated portion 32b are regions where the metal surface of the electrode foil is exposed, and are arranged at positions on one side and the other side in the winding axis direction as shown in FIG. Be beaten by.

負極板３２においては、負極活物質として非晶質炭素粉末１００重量部に対して、結着剤として１０重量部のポリフッ化ビニリデン（以下、ＰＶＤＦという。）を添加し、これに分散溶媒としてＮ−メチルピロリドン（以下、ＮＭＰという。）を添加、混練した負極合剤を作製した。この負極合剤を厚さ１０μｍの銅箔（負極電極箔）の両面に集電部（負極未塗工部）を残して塗布した。その後、乾燥、プレス、裁断して銅箔を含まない負極活物質塗布部厚さ７０μｍの負極板を得た。 In the negative electrode plate 32, 10 parts by weight of polyvinylidene fluoride (hereinafter referred to as PVDF) is added as a binder to 100 parts by weight of amorphous carbon powder as a negative electrode active material, and N as a dispersion solvent. -A negative electrode mixture in which methylpyrrolidone (hereinafter referred to as NMP) was added and kneaded was prepared. This negative electrode mixture was applied to both surfaces of a 10 μm thick copper foil (negative electrode electrode foil) leaving a current collecting portion (negative electrode uncoated portion). Thereafter, drying, pressing, and cutting were performed to obtain a negative electrode plate having a thickness of 70 μm, which does not include a copper foil.

なお、本実施の形態では、負極活物質に非晶質炭素を用いる場合について例示したが、これに限定されるものではなく、リチウムイオンを挿入、脱離可能な天然黒鉛や、人造の各種黒鉛材、コークスなどの炭素質材料等でよく、その粒子形状においても、鱗片状、球状、繊維状、塊状等、特に制限されるものではない。 In this embodiment, the case where amorphous carbon is used as the negative electrode active material is exemplified, but the present invention is not limited to this, and natural graphite capable of inserting and removing lithium ions and various artificial graphites are not limited thereto. The material may be a carbonaceous material such as a material or coke, and the particle shape is not particularly limited to a scale shape, a spherical shape, a fiber shape, a lump shape, or the like.

正極板３４に関しては、正極活物質としてマンガン酸リチウム（化学式ＬｉＭｎ_２Ｏ_４）１００重量部に対し、導電材として１０重量部の鱗片状黒鉛と結着剤として１０重量部のＰＶＤＦとを添加し、これに分散溶媒としてＮＭＰを添加、混練した正極合剤を作製した。この正極合剤を厚さ２０μｍのアルミニウム箔（正極電極箔）の両面に無地の集電部（正極未塗工部）を残して塗布した。その後、乾燥、プレス、裁断してアルミニウム箔を含まない正極活物質塗布部厚さ９０μｍの正極板を得た。 Regarding the positive electrode plate 34, 10 parts by weight of flaky graphite as a conductive material and 10 parts by weight of PVDF as a binder are added to 100 parts by weight of lithium manganate (chemical formula LiMn ₂ O ₄ ) as a positive electrode active material. A positive electrode mixture was prepared by adding and kneading NMP as a dispersion solvent. This positive electrode material mixture was applied to both surfaces of a 20 μm thick aluminum foil (positive electrode electrode foil) leaving a plain current collecting part (positive electrode uncoated part). Thereafter, drying, pressing, and cutting were performed to obtain a positive electrode plate with a thickness of 90 μm, which does not include an aluminum foil.

また、本実施の形態では、正極活物質にマンガン酸リチウムを用いる場合について例示したが、スピネル結晶構造を有する他のマンガン酸リチウムや一部を金属元素で置換又はドープしたリチウムマンガン複合酸化物や層状結晶構造を有すコバルト酸リチウムやチタン酸リチウムやこれらの一部を金属元素で置換またはドープしたリチウム-金属複合酸化物を用いるようにしてもよい。 Further, in the present embodiment, the case where lithium manganate is used as the positive electrode active material is exemplified, but other lithium manganate having a spinel crystal structure or a lithium manganese composite oxide partially substituted or doped with a metal element or A lithium cobalt oxide or lithium titanate having a layered crystal structure, or a lithium-metal composite oxide in which a part thereof is substituted or doped with a metal element may be used.

また、本実施の形態では、正極板、負極板における塗工部の結着材としてＰＶＤＦを用いる場合について例示したが、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリエチレン、ポリスチレン、ポリブタジエン、ブチルゴム、ニトリルゴム、スチレンブタジエンゴム、多硫化ゴム、ニトロセルロース、シアノエチルセルロース、各種ラテックス、アクリロニトリル、フッ化ビニル、フッ化ビニリデン、フッ化プロピレン、フッ化クロロプレン、アクリル系樹脂などの重合体およびこれらの混合体などを用いることができる。 In the present embodiment, the case where PVDF is used as the binder of the coating portion in the positive electrode plate and the negative electrode plate is exemplified, but polytetrafluoroethylene (PTFE), polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, Use polymers such as styrene butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile, vinyl fluoride, vinylidene fluoride, propylene fluoride, chloroprene, acrylic resins, and mixtures thereof. be able to.

次に、本発明の特徴的な構成要素である絶縁保護フィルム４１の構成について詳細に説明する。なお、絶縁保護フィルム４１は、例えば図２に示すように、透明な部材からなるものを例として示しているが、透明に限定されるものではなく、不透明であってもよい。 Next, the configuration of the insulating protective film 41, which is a characteristic component of the present invention, will be described in detail. As shown in FIG. 2, for example, the insulating protective film 41 is made of a transparent member, but is not limited to being transparent, and may be opaque.

図４は本発明の絶縁保護フィルム４１の展開図、図５は絶縁保護フィルムと発電要素組立体の位置関係を説明する斜視図、図６は絶縁保護フィルムで捲回電極体の側面を覆った状態を示す斜視図、図７は絶縁保護フィルムで捲回電極体の底面を覆った状態を示す斜視図、図８は絶縁保護フィルムに覆われた発電要素組立体を電池缶に挿入する状態を示す図、図９は図１の縦断面図である。 4 is a development view of the insulating protective film 41 of the present invention, FIG. 5 is a perspective view for explaining the positional relationship between the insulating protective film and the power generation element assembly, and FIG. 6 covers the side surface of the wound electrode body with the insulating protective film. 7 is a perspective view showing a state in which the bottom surface of the wound electrode body is covered with an insulating protective film, and FIG. 8 is a state in which the power generating element assembly covered with the insulating protective film is inserted into the battery can. FIG. 9 is a longitudinal sectional view of FIG.

従来のリチウムイオン二次電池は、絶縁性のシートを複雑に折り曲げて箱状に形成し、その中に捲回電極体を収容し、位置がずれないように電池缶に挿入する必要があり、自動化が困難で生産性に欠けるという問題があった。 A conventional lithium ion secondary battery is formed in a box shape by intricately bending an insulating sheet, and a wound electrode body must be accommodated therein and inserted into a battery can so that the position does not shift, There was a problem that automation was difficult and productivity was lacking.

これに対して、本実施の形態におけるリチウムイオン二次電池１は、図５、図６に示すように、発電要素組立体５の捲回電極体３１に対して、捲回電極体３１の捲回軸方向に直交する方向にシート状の絶縁保護フィルム４１を巻き付けて、捲回電極体３１の外周が連続して少なくとも一周以上、接続端子５３、６３ごと、すなわち、接続端子５３、６３と共にその外側を覆っている。 On the other hand, as shown in FIGS. 5 and 6, the lithium ion secondary battery 1 in the present embodiment has a wound electrode body 31 wound with respect to the wound electrode body 31 of the power generation element assembly 5. The sheet-like insulating protective film 41 is wound in a direction orthogonal to the rotational axis direction, and the outer periphery of the wound electrode body 31 is continuously at least one or more rounds, together with the connection terminals 53 and 63, that is, together with the connection terminals 53 and 63 Covers the outside.

そして、図６〜図９に示すように、絶縁保護フィルム４１の側面カバー部４２から突出する底面カバー部４３によって捲回電極体３１の底面である下側の湾曲部を覆っており、底面カバー部４３に連続して設けられた折り返し片部である第１折り返し片４４と第２折り返し片４５がそれぞれ捲回電極体３１と電池缶１１との間に介在される構成を有している。 As shown in FIGS. 6 to 9, the bottom surface cover portion 43 protruding from the side surface cover portion 42 of the insulating protective film 41 covers the lower curved portion that is the bottom surface of the wound electrode body 31, and the bottom surface cover The first folded piece 44 and the second folded piece 45, which are folded pieces provided continuously to the portion 43, are interposed between the wound electrode body 31 and the battery can 11, respectively.

したがって、絶縁保護フィルム４１によって捲回電極体３１の側面と下面を簡単に覆うことができ、捲回電極体３１を電池缶１１に挿入する際に絶縁保護フィルム４１の位置ずれを生ずることなく容易に挿入でき、自動化が簡単で生産性に優れている。 Therefore, the side surface and the lower surface of the wound electrode body 31 can be easily covered with the insulating protective film 41, and the insulating protective film 41 is easily displaced without being displaced when the wound electrode body 31 is inserted into the battery can 11. It is easy to automate and has excellent productivity.

絶縁保護フィルム４１は、捲回電極体３１の扁平面に沿う方向でかつ捲回電極体３１の捲回軸方向に直交する方向を中心軸方向として捲回電極体３１の周囲に１周以上巻き付けられて捲回電極体３１の側面を覆う側面カバー部４２と、側面カバー部４２から突出して捲回電極体３１の下側の湾曲部を覆う底面カバー部４３と、底面カバー部４３から突出して捲回電極体３１の側面と電池缶１１の縦壁部である幅広側面ＰＷ、幅狭側面ＰＮとの間に介在される折り返し片部である第１折り返し片４４と第２折り返し片４５を有している。 The insulating protective film 41 is wound around the circumference of the wound electrode body 31 by taking a direction along the flat surface of the wound electrode body 31 and a direction perpendicular to the wound axis direction of the wound electrode body 31 as a central axis direction. A side cover portion 42 covering the side surface of the wound electrode body 31, a bottom surface cover portion 43 projecting from the side surface cover portion 42 and covering the lower curved portion of the wound electrode body 31, and projecting from the bottom surface cover portion 43. There are a first folded piece 44 and a second folded piece 45 which are folded pieces interposed between the side surface of the wound electrode body 31 and the wide side surface PW which is the vertical wall portion of the battery can 11 and the narrow side surface PN. doing.

側面カバー部４２は、図４に示すように、捲回電極体３１の扁平面に対向する一対の扁平面対向部４２ａ、４２ｂと、捲回電極体３１の捲回軸方向両側の端面に対向する一対の端面対向部４２ｃ、４２ｄを有する。一対の扁平面対向部４２ａ、４２ｂのうち、捲回電極体３１の正面側に配置される扁平面対向部（他方の扁平面対向部）４２ｂは、捲回電極体３１の背面側に配置される扁平面対向部（一方の扁平面対向部）４２ａを間に介して、側面カバー部４２の長手方向一方側の第１部分４２ｂ１と他方側の第２部分４２ｂ２の２つに分かれており、これら第１部分４２ｂ１と第２部分４２ｂ２の端部に設けられている重ね代Ｋ１、Ｋ２を互いに重ねることによって形成される。 As shown in FIG. 4, the side cover portion 42 is opposed to a pair of flat surface facing portions 42 a and 42 b facing the flat surface of the wound electrode body 31, and end surfaces on both sides in the winding axis direction of the wound electrode body 31. A pair of end face facing portions 42c and 42d. Of the pair of flat surface facing portions 42a and 42b, the flat surface facing portion (the other flat surface facing portion) 42b disposed on the front side of the wound electrode body 31 is disposed on the back side of the wound electrode body 31. The first flat portion 42b1 on the one side in the longitudinal direction of the side surface cover portion 42 and the second portion 42b2 on the other side are sandwiched through a flat flat surface facing portion (one flat flat surface facing portion) 42a. The overlapping portions K1 and K2 provided at the end portions of the first portion 42b1 and the second portion 42b2 are overlapped with each other.

扁平面対向部４２ｂの第１部分４２ｂ１と第２部分４２ｂ２は、長手方向の長さが互いに異なっており、重ね代Ｋ１、Ｋ２が捲回電極体３１の正面側の扁平面に対向する位置で且つ捲回軸方向一方側に偏位した位置に配置されるように設定されている。したがって、捲回電極体３１のセパレータ３５の捲き終わり端部を固定する粘着テープの上に重ね代が重なるのを防ぎ、捲回電極体３１の扁平厚さが厚くなるのを抑制することができる。なお、捲回軸方向一方側に偏位した位置に配置されるのは必須ではなく、例えば捲回軸方向中央位置や、捲回電極体３１の側端面に対向する位置に重ね代Ｋ１、Ｋ２が配置される構成としてもよい。 The first portion 42b1 and the second portion 42b2 of the flat plane facing portion 42b have different lengths in the longitudinal direction, and the overlapping margins K1 and K2 are at positions where the flat surfaces on the front side of the wound electrode body 31 are opposed to each other. And it is set so that it may be arranged at a position deviated to one side in the winding axis direction. Therefore, it is possible to prevent the overlap margin from overlapping on the adhesive tape that fixes the winding end of the separator 35 of the wound electrode body 31, and to prevent the flat thickness of the wound electrode body 31 from increasing. . In addition, it is not essential to be disposed at a position deviated to one side in the winding axis direction. For example, the overlap margins K1 and K2 are arranged at the center position in the winding axis direction or the position facing the side end surface of the winding electrode body 31. It is good also as a structure by which.

底面カバー部４３は、側面カバー部４２の扁平面対向部４２ａの下端から突出しており、捲回電極体３１の下側の湾曲部に対向して巻き付けられる。第１折り返し片４４は、底面カバー部４３の先端から突出して捲回電極体３１の扁平面と電池缶１１の縦壁部の一部を構成する幅広側面ＰＷとの間に介在される。第２折り返し片４５は、底面カバー部４３の両側端から互いに離反する方向にそれぞれ突出して捲回電極体３１の捲回軸方向両側の端面と電池缶１１の縦壁部の一部を構成する幅狭側面ＰＮとの間に介在される。 The bottom surface cover portion 43 protrudes from the lower end of the flat surface facing portion 42 a of the side surface cover portion 42, and is wound around the lower curved portion of the wound electrode body 31. The first folded piece 44 protrudes from the tip of the bottom cover portion 43 and is interposed between the flat surface of the wound electrode body 31 and the wide side surface PW constituting a part of the vertical wall portion of the battery can 11. The second folded pieces 45 protrude in directions away from both side ends of the bottom surface cover portion 43 to constitute end surfaces on both sides in the winding axis direction of the wound electrode body 31 and a part of the vertical wall portion of the battery can 11. It is interposed between the narrow side surface PN.

絶縁保護フィルム４１は、図４に示すように、上部の横長矩形部分が側面カバー部４２を形成し、側面カバー部４２から突出する下部の十字形状部分が底面カバー部４３及び折り返し片部４４、４５を形成する。絶縁保護フィルム４１の寸法条件は、少なくとも図中、Ｌ１〜Ｌ７が重要となる。 As shown in FIG. 4, the insulating protective film 41 has an upper horizontally long rectangular portion forming a side cover portion 42, and a lower cross-shaped portion protruding from the side cover portion 42 is a bottom cover portion 43 and a folded piece portion 44, 45 is formed. As for the dimensional conditions of the insulating protective film 41, at least L1 to L7 are important in the drawing.

上部の横長矩形部分を構成する側面カバー部４２の長手方向長さＬ１は、捲回電極体３１の外周が連続して少なくとも一周以上、接続端子５３、６３ごと覆うことができる長さに設定され、幅方向長さＬ２は、電池蓋２１の下面から少なくとも捲回電極体３１の電池缶１１底面側の平坦部端部までを覆う長さに設定されている。 The length L1 in the longitudinal direction of the side cover portion 42 constituting the upper horizontally long rectangular portion is set to a length that allows the outer circumference of the wound electrode body 31 to be continuously covered with the connection terminals 53 and 63 at least once. The length L2 in the width direction is set to a length that covers from the lower surface of the battery lid 21 to at least the flat portion end of the wound electrode body 31 on the bottom surface side of the battery can 11.

下部の十字形状部分を構成する底面カバー部４３及び第１折り返し片４４の横幅Ｌ３は、電池缶１１の長手方向における接続端子５３、６３の外側端間の長さよりも大きく、電池缶１１の長手方向の内側寸法（幅広側面の幅）以下に設定されている。 The lateral width L3 of the bottom cover portion 43 and the first folded piece 44 constituting the lower cross-shaped portion is larger than the length between the outer ends of the connection terminals 53 and 63 in the longitudinal direction of the battery can 11 and is longer than the longitudinal length of the battery can 11. It is set to be smaller than the inner dimension (width of the wide side surface) in the direction.

底面カバー部４３の突出長さＬ４は、捲回電極体３１の下側の湾曲部に沿って覆う長さに設定されている。第１折り返し片４４の突出長さＬ５は、側面カバー部４２の扁平面対向部４２ｂの外側で電池缶１１の幅広側面ＰＷとの間に先端が介在される長さに設定されている。 The protruding length L4 of the bottom cover portion 43 is set to a length that covers the lower curved portion of the wound electrode body 31. The protruding length L5 of the first folded piece 44 is set to a length at which the tip is interposed between the wide side surface PW of the battery can 11 outside the flat surface facing portion 42b of the side cover portion 42.

下部の十字形状部分のうち、底面カバー部４３の両側端から互いに離反する方向に突出する第２折り返し片４５の幅Ｌ６は、捲回電極体３１の扁平厚さよりも大きく、電池缶１１の短手方向の内側寸法（幅狭側面の幅）よりも短い大きさに設定されている。そして、第２折り返し片４５の突出高さＬ７は、側面カバー部４２の端面対向部４２ｃの外側で電池缶１１の幅狭側面ＰＮとの間に先端が介在されて、捲回電極体３１の下側の端面部分３１ａを覆う長さに設定されている。 Of the lower cross-shaped portion, the width L6 of the second folded piece 45 protruding in the direction away from the both side ends of the bottom cover portion 43 is larger than the flat thickness of the wound electrode body 31, and is shorter than the battery can 11. The size is set to be shorter than the inner dimension in the hand direction (width of the narrow side surface). And the protrusion height L7 of the 2nd folding | turning piece 45 has a front-end | tip interposed between the narrow side surface PN of the battery can 11 on the outer side of the end surface opposing part 42c of the side surface cover part 42, and the winding electrode body 31 of FIG. The length is set to cover the lower end surface portion 31a.

絶縁保護フィルム４１は、例えばPP（ポリプロピレン）などの合成樹脂製の一枚のシート部材からなり、捲回電極体３１の扁平面と平行な方向でかつ捲回軸方向に直交する方向（図５のＹ軸方向）を巻き付け中心として一周以上巻き付けることができる長さを有しており、巻き付けた状態で電池缶１１の底部側に配置される絶縁保護フィルム４１の下部の十字形状が、捲回電極体３１の電池缶１１の底部側を覆うように構成されている。 The insulating protective film 41 is made of a single sheet member made of synthetic resin such as PP (polypropylene), for example, and is in a direction parallel to the flat surface of the wound electrode body 31 and perpendicular to the winding axis direction (FIG. 5). The Y-axis direction) is a length that can be wound more than one turn around the winding center, and the cross shape at the bottom of the insulating protective film 41 arranged on the bottom side of the battery can 11 in the wound state is The electrode body 31 is configured to cover the bottom side of the battery can 11.

絶縁保護フィルムの厚さは、０．０１ｍｍから０．５０ｍｍが好ましく、更に、０．０３ｍｍから０．２０ｍｍがより好ましい。但し、電池内部の空間体積が大きい場合はこれに限ったものではなく、例えば絶縁保護フィルム４１の厚みは、捲回電極体３１と電池容器２との間に介在出来き、且つ絶縁を保ち、発電要素を保護可能な厚みであればこれに限定されるものではない。 The thickness of the insulating protective film is preferably 0.01 mm to 0.50 mm, and more preferably 0.03 mm to 0.20 mm. However, when the space volume inside the battery is large, it is not limited to this. For example, the thickness of the insulating protective film 41 can be interposed between the wound electrode body 31 and the battery container 2 and maintains insulation. The thickness is not limited to this as long as the power generation element can be protected.

なお、本実施の形態では、絶縁保護フィルム４１の材料としてPPを使用した場合を例に示したが、これに限定されるものではなく、例えば、PFA（ポリテトラフルオロエチレン）、PPS（ポリフェニレンサルファイド）、PET（ポリエチレンテレフタレート）や、電解液により反応や変質しない素材の合成樹脂であれば用いることができる。また、絶縁保護フィルム４１の長さは、上記した例に限定されるものではなく、少なくとも一周以上であればよく、例えば二周以上、巻き付けられる長さであってもよい。 In the present embodiment, the case where PP is used as the material of the insulating protective film 41 is shown as an example. However, the present invention is not limited to this. For example, PFA (polytetrafluoroethylene), PPS (polyphenylene sulfide) is used. ), PET (polyethylene terephthalate), or any synthetic resin that does not react or change quality due to the electrolyte. Moreover, the length of the insulating protective film 41 is not limited to the above-described example, and may be at least one round, for example, two or more rounds.

絶縁保護フィルム４１は、電池蓋２１の側面に重ならない程度に近接する位置に、絶縁保護フィルム４１の幅方向一方側（図５〜図８では上側）の端部が配置されるように巻き付けられる。本実施の形態では、絶縁保護フィルム４１の上端部と電池蓋との間に0.5ｍｍ程度の離間距離が形成されるように巻き付けられている。 The insulating protective film 41 is wound so that the end of one side in the width direction of the insulating protective film 41 (the upper side in FIGS. 5 to 8) is arranged at a position close enough not to overlap the side surface of the battery lid 21. . In the present embodiment, the insulation protective film 41 is wound such that a separation distance of about 0.5 mm is formed between the upper end portion of the insulating protective film 41 and the battery lid.

次に、絶縁保護フィルム４１の装着方法について説明する。
まず、発電要素組立体５の電池蓋２１の裏面に、縁保護フィルム４１の幅方向一方側（図５の＋Ｙ方向側）の端部である上端が合うように配置する。この際、捲回電極体３１の一方の扁平面に扁平面対向部４２ａが対向配置されて、絶縁保護フィルム４１の下部の十字形状部分が捲回電極体３１の扁平面と位置合わせされる。 Next, a method for attaching the insulating protective film 41 will be described.
First, it arrange | positions so that the upper end which is an edge part of the width direction one side (+ Y direction side of FIG. 5) of the edge protection film 41 may fit in the back surface of the battery cover 21 of the electric power generation element assembly 5. FIG. At this time, the flat surface facing portion 42 a is disposed opposite to one flat surface of the wound electrode body 31, and the cross-shaped portion below the insulating protective film 41 is aligned with the flat surface of the wound electrode body 31.

次に、縁保護フィルム４１の上部矩形部の両端を、図５の矢印Ｉ、ＩＩで示すように、外側から接続端子５３、６３ごと覆うように巻き付ける。そして、絶縁保護フィルム４１の下部の十字形状部分を、図６の矢印ＩＩＩに示すように、折り返す。 Next, as shown by arrows I and II in FIG. 5, both ends of the upper rectangular portion of the edge protective film 41 are wound so as to cover the connection terminals 53 and 63 from the outside. Then, the cross-shaped portion at the bottom of the insulating protective film 41 is folded back as shown by an arrow III in FIG.

それから、底面カバー部４３を、図７に示すように、捲回電極体３１の下側の湾曲部に沿って巻き付けて、第１折り返し片４４を、捲回電極体３１の正面側の扁平面に対向する位置に配置して、側面カバー部４２の扁平面対向部４２ｂの外側に重ねた状態で配置する。したがって、底面カバー部４３は、捲回電極体３１の下側の湾曲部に沿って湾曲した形状とされる。 Then, as shown in FIG. 7, the bottom cover portion 43 is wound along the lower curved portion of the wound electrode body 31, and the first folded piece 44 is flattened on the front side of the wound electrode body 31. It arrange | positions in the position which opposes, and arrange | positions in the state accumulated on the outer side of the flat surface opposing part 42b of the side surface cover part 42. FIG. Therefore, the bottom surface cover portion 43 is curved along the lower curved portion of the wound electrode body 31.

そして、一対の第２折り返し片４５は、底面カバー部４３の湾曲形状に沿って下に凸状に湾曲した状態で捲回電極体３１の端面から捲回軸方向両側に向かって突出する形状とされる。これにより、電池蓋２１を除く発電要素組立体５は、図７に示すように、捲回電極体３１の下側の端面を除いて、絶縁保護フィルム４１に覆われた状態とされる。 The pair of second folded pieces 45 has a shape that protrudes toward both sides in the winding axis direction from the end face of the wound electrode body 31 in a state of being convexly curved downward along the curved shape of the bottom surface cover portion 43. Is done. As a result, the power generating element assembly 5 excluding the battery lid 21 is covered with the insulating protective film 41 except for the lower end surface of the wound electrode body 31 as shown in FIG.

絶縁保護フィルム４１は、側面カバー部４２によって捲回電極体３１の外周を接続端子５３、６３ごと覆い、次いで、底面カバー部４３によって捲回電極体３１の下側の湾曲部を覆った後に、絶縁保護フィルム４１の互いに重なる部分同士が粘着テープ（図示せず）で固定される。粘着テープによる固定箇所は、側面カバー部４２の重ね代Ｋ１、Ｋ２を留める第１箇所と、第１折り返し片４４を側面カバー部４２の外側に留める第２箇所の２箇所が設定されているが、第２箇所のみであってもよい。なお、固定方法としては、粘着テープで留める方法の他に、接着剤で留めてもよい。また、例えば一方のフィルム面に電解液によって反応や変質しない粘着材が塗布されたシール状の粘着フィルムや、フィルム同士が面着されるラップフィルムを用いてもよく、粘着テープや接着剤を用いた場合よりも、容易に固定することができる。 The insulating protective film 41 covers the outer periphery of the wound electrode body 31 together with the connection terminals 53 and 63 by the side cover portion 42, and then covers the lower curved portion of the wound electrode body 31 by the bottom surface cover portion 43. The overlapping portions of the insulating protective film 41 are fixed with an adhesive tape (not shown). There are two places fixed by the adhesive tape, the first place where the overlap margins K1 and K2 of the side cover portion 42 are fastened and the second place where the first folded piece 44 is fastened to the outside of the side cover portion 42. Only the second location may be used. In addition, as a fixing method, you may fasten with an adhesive agent other than the method of fastening with an adhesive tape. In addition, for example, a seal-like adhesive film in which an adhesive that does not react or change with the electrolyte solution is applied to one film surface, or a wrap film on which the films are attached may be used, and an adhesive tape or an adhesive is used. It can be fixed more easily than if it were.

次に、上記構成を有するリチウムイオン二次電池１の製造方法について説明する。 Next, a method for manufacturing the lithium ion secondary battery 1 having the above configuration will be described.

まず、正極板３４と負極板３２を、間にセパレータ３３、３５を介在させて重ねあわせ、扁平状に捲回することにより、発電要素３である捲回電極体３１を作製する。次に、電池蓋２１に絶縁部材を介して正極端子５１と負極端子６１を取り付けて蓋組立体４を作製する。そして、蓋組立体４の正極端子５１と負極端子６１に、捲回電極体３１の正極未塗工部３４ｂと負極未塗工部３２ｂを超音波接合して導通接続し、発電要素組立体５を作製する。 First, the positive electrode plate 34 and the negative electrode plate 32 are overlapped with the separators 33 and 35 interposed therebetween, and wound in a flat shape, whereby the wound electrode body 31 that is the power generation element 3 is manufactured. Next, the positive electrode terminal 51 and the negative electrode terminal 61 are attached to the battery lid 21 via an insulating member to produce the lid assembly 4. Then, the positive electrode uncoated portion 34b and the negative electrode uncoated portion 32b of the wound electrode body 31 are ultrasonically joined to the positive electrode terminal 51 and the negative electrode terminal 61 of the lid assembly 4 and conductively connected, thereby generating the power generation element assembly 5. Is made.

それから、絶縁保護フィルム４１の側面カバー部４２を発電要素組立体５の捲回電極体３１の外周に１周以上巻き付けて、側面カバー部４２で捲回電極体３１の側面を接続端子５３、６３ごと覆い、解けないように、絶縁保護フィルム４１の端部を粘着テープで留める。 Then, the side cover portion 42 of the insulating protective film 41 is wound around the outer periphery of the wound electrode body 31 of the power generation element assembly 5 at least once, and the side surface of the wound electrode body 31 is connected to the connection terminals 53 and 63 by the side cover portion 42. The end portion of the insulating protective film 41 is fastened with an adhesive tape so as not to be unwound.

そして、絶縁保護フィルム４１の下部の底面カバー部４３を捲回電極体３１の下側の湾曲部に対向して巻き付けて、底面カバー部４３で捲回電極体３１の下側の湾曲面を覆う。そして、第１折り返し片４４を側面カバー部４２の扁平面対向部４２ｂの外側に対向して配置させた後、側面カバー部４２及び第１折り返し片４４が解けないように粘着テープで留めて固定し、捲回電極体３１を覆う。 Then, the bottom cover portion 43 below the insulating protective film 41 is wound around the lower curved portion of the wound electrode body 31, and the lower curved surface of the wound electrode body 31 is covered with the bottom cover portion 43. . Then, after the first folded piece 44 is disposed so as to be opposed to the outer side of the flat surface facing part 42b of the side cover part 42, the first folded piece 44 is fixed with an adhesive tape so that the side cover part 42 and the first folded piece 44 cannot be unwound. Then, the wound electrode body 31 is covered.

そして、絶縁保護フィルム４１に覆われた捲回電極体３１を電池缶１１の開口部１１ａから電池缶１１内に挿入する。捲回電極体３１を電池缶１１に挿入する際、一対の第２折り返し片４５は、電池缶１１の開口部１１ａに当接して、電池蓋２１側に向かって折曲され、捲回電極体３１の下側の端面に対向し、電池缶１１の幅狭側面ＰＮと捲回電極体３１の端面との間に介在されて覆う。したがって、捲回電極体３１は、その側面及び底面が絶縁保護フィルム４１によって覆われた状態で電池缶１１内に収容される。 Then, the wound electrode body 31 covered with the insulating protective film 41 is inserted into the battery can 11 from the opening 11 a of the battery can 11. When inserting the wound electrode body 31 into the battery can 11, the pair of second folded pieces 45 are in contact with the opening 11 a of the battery can 11, bent toward the battery lid 21, and wound electrode body. It faces the lower end surface of 31 and covers and covers between the narrow side surface PN of the battery can 11 and the end surface of the wound electrode body 31. Therefore, the wound electrode body 31 is accommodated in the battery can 11 in a state where the side surface and the bottom surface are covered with the insulating protective film 41.

電池蓋２１と電池缶１１とをレーザ溶接により溶接して開口部１１ａを封止する。そして、外部端子５２、６２を介して捲回電極体３１から外部負荷に電力が供給され、あるいは、外部端子５２、６２を介して外部発電電力が捲回電極体３１に充電される。 The battery lid 21 and the battery can 11 are welded by laser welding to seal the opening 11a. Then, electric power is supplied from the wound electrode body 31 to the external load via the external terminals 52 and 62, or external generated power is charged to the wound electrode body 31 via the external terminals 52 and 62.

上記した本実施の形態のリチウムイオン二次電池１は、発電要素組立体５の捲回電極体３１にシート状の絶縁保護フィルム４１が巻き付けられており、捲回電極体３１の外周が連続して少なくとも一周、接続端子５３、６３ごと覆われている。 In the lithium ion secondary battery 1 of the above-described embodiment, the sheet-like insulating protective film 41 is wound around the wound electrode body 31 of the power generation element assembly 5, and the outer periphery of the wound electrode body 31 is continuous. The connection terminals 53 and 63 are covered at least once.

絶縁保護フィルム４１は、捲回電極体３１及び接続端子５３、６３と電池缶１１との間に介在されて捲回電極体３１及び接続端子５３、６３と電池缶１１との間を絶縁し、捲回電極体３１及び接続端子５３、６３を保護することができる。 The insulating protective film 41 is interposed between the wound electrode body 31 and the connection terminals 53 and 63 and the battery can 11 to insulate between the wound electrode body 31 and the connection terminals 53 and 63 and the battery can 11. The wound electrode body 31 and the connection terminals 53 and 63 can be protected.

絶縁保護フィルム４１の装着は、側面カバー部４２を捲回電極体３１の周囲に１周以上巻き付けて捲回電極体３１の側面を覆い、底面カバー部４３で捲回電極体３１の下側の湾曲部を覆い、折り返し片部である第１折り返し片４４と第２折り返し片４５を側面カバー部４２の外側に対向配置することによって行うことができ、捲回電極体３１に対して位置ずれが防止された状態で装着することができる。 The insulating protective film 41 is attached by winding the side cover portion 42 around the wound electrode body 31 one or more times to cover the side surface of the wound electrode body 31, and the bottom cover portion 43 below the wound electrode body 31. The curved portion is covered, and the first folded piece 44 and the second folded piece 45, which are the folded pieces, can be arranged opposite to the outside of the side cover part 42, and the positional deviation with respect to the wound electrode body 31 can be achieved. Can be mounted in a prevented state.

したがって、従来のように絶縁保護フィルムを複雑に折り曲げて袋状に形成し、それに電池蓋と一体となった捲回群を内包し、さらに電池缶に挿入する工程を削減できる。したがって、従来と比較して簡単に装着でき、捲回電極体３１の電池缶１１への挿入も簡単に行うことができ、挿入する際に位置ずれが生ずるのを防ぐことができる。したがって、生産性に優れたリチウムイオン二次電池１を製造することができる。 Therefore, it is possible to reduce the steps of forming the bag by forming the insulating protective film in a complicated manner as in the prior art, enclosing the wound group integrated with the battery lid, and inserting the wound group into the battery can. Therefore, it can be easily mounted as compared with the conventional case, the winding electrode body 31 can be easily inserted into the battery can 11, and it is possible to prevent the occurrence of displacement in the insertion. Therefore, the lithium ion secondary battery 1 excellent in productivity can be manufactured.

また、フィルムやシートと連続して覆う技術は、電池以外でも一般的に広く使われているので、自動化が比較的容易にでき、設備の導入コストを抑えることもできる。さらに、従来のように、絶縁保護フィルムを複雑に折り曲げる必要がないため、絶縁保護フィルムのコストも抑制することができる。 Moreover, since the technique of covering continuously with a film or sheet is widely used in addition to batteries, it can be relatively easily automated and the cost of introducing equipment can be reduced. Furthermore, since it is not necessary to bend the insulating protective film in a complicated manner as in the prior art, the cost of the insulating protective film can be suppressed.

上記した構成を有する絶縁保護フィルム４１によれば、第１折り返し片４４と第２折り返し片４５によって側面カバー部４２の下端を覆っているので、捲回電極体３１を電池缶１１に挿入する際に、側面カバー部４２の下端が電池缶１１の開口部１１ａに当接して引っ掛かるのを防ぐことができる。したがって、リチウムイオン二次電池１の組み立て作業を容易にすることができ、かかる作業を自動化して生産性の向上を図ることができる。 According to the insulating protective film 41 having the above-described configuration, the lower end of the side surface cover portion 42 is covered by the first folded piece 44 and the second folded piece 45, and therefore when the wound electrode body 31 is inserted into the battery can 11. In addition, the lower end of the side cover portion 42 can be prevented from coming into contact with the opening 11 a of the battery can 11 and being caught. Therefore, the assembly operation of the lithium ion secondary battery 1 can be facilitated, and the productivity can be improved by automating the operation.

また、上記した構成によれば、一対の第２折り返し片４５は、捲回電極体３１に装着された状態で、電池蓋２１から離反する方向である下方に向かって凸状に湾曲した形状を有しているので、図７及び図８に示すように、電池缶１１の開口部１１ａから電池缶１１内に捲回電極体３１を挿入する前までは、捲回電極体３１の捲回軸方向に沿って互いに離反する方向に向かって突出する姿勢状態を保つことができる。 In addition, according to the above-described configuration, the pair of second folded pieces 45 has a shape curved in a convex shape toward the lower side, which is a direction away from the battery lid 21, while being attached to the wound electrode body 31. 7 and FIG. 8, the winding shaft of the wound electrode body 31 is inserted from the opening 11 a of the battery can 11 until the wound electrode body 31 is inserted into the battery can 11. It is possible to maintain a posture state that protrudes in directions away from each other along the direction.

したがって、捲回電極体３１を電池缶１１に挿入する際に、一対の第２折り返し片４５を電池缶１１の開口部１１ａに当接させて、より具体的には、開口部１１ａで且つ電池缶１１の幅狭側面ＰＮの上端に相当する部分に当接させて、電池蓋２１側に向かって確実に折曲させることができ、図９に示すように、これら一対の第２折り返し片４５によって捲回電極体３１の下側の端面を覆うことができる。 Therefore, when inserting the wound electrode body 31 into the battery can 11, the pair of second folded pieces 45 are brought into contact with the opening 11 a of the battery can 11, more specifically, the opening 11 a and the battery The can 11 can be brought into contact with a portion corresponding to the upper end of the narrow side surface PN of the can 11 and can be reliably bent toward the battery lid 21 side. As shown in FIG. Thus, the lower end face of the wound electrode body 31 can be covered.

なお、本発明の構成は、上記した実施の形態の構成に限定されるものではなく、種々の変更が可能である。例えば、上記した構成では、第１折り返し片４４と第２折り返し片４５をそれぞれ、側面カバー部４２の外側に配置する場合を例に説明したが、第１折り返し片４４もしくは第２折り返し片４５の少なくとも一方を、捲回電極体３１の扁平面に対向配置して当接させた後で、側面カバー部４２を巻き付けてもよい。 In addition, the structure of this invention is not limited to the structure of above-described embodiment, A various change is possible. For example, in the above-described configuration, the case where the first folded piece 44 and the second folded piece 45 are respectively disposed outside the side surface cover portion 42 has been described as an example, but the first folded piece 44 or the second folded piece 45 The side cover portion 42 may be wound after at least one of the electrodes is disposed so as to face and contact the flat surface of the wound electrode body 31.

＜第２実施の形態＞
次に、本発明の第２実施の形態について図面を用いて説明する。
なお、第１実施の形態と同様の構成要素には、同一の符号を付することでその詳細な説明を省略する。 <Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to the drawings.
Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

本実施の形態において特徴的なことは、側面カバー部４２の幅方向長さＬ２を第１実施の形態の長さＬ２よりも長くして、絶縁保護フィルム４１の底面を略平面形状とし、第１実施の形態の絶縁保護フィルム４１から第２折り返し片４５を省略した構成としたことである。 What is characteristic in the present embodiment is that the length L2 of the side cover portion 42 in the width direction is longer than the length L2 of the first embodiment, the bottom surface of the insulating protective film 41 is substantially planar, In other words, the second folded piece 45 is omitted from the insulating protective film 41 of the first embodiment.

図１０から図１４は、第１実施の形態における図４から図８に対応する図である。 FIGS. 10 to 14 correspond to FIGS. 4 to 8 in the first embodiment.

絶縁保護フィルム４１’は、図１０に示すように、側面カバー部４２と、底面カバー部４３と、第１折り返し片４４を有している。 As shown in FIG. 10, the insulating protective film 41 ′ includes a side surface cover portion 42, a bottom surface cover portion 43, and a first folded piece 44.

側面カバー部４２の幅方向長さＬ２は、上端が電池蓋２１の下面に対向する位置に配置され、下端が捲回電極体３１の下側の湾曲部の最下端と略同じ位置に配置される長さに設定されている。 The width direction length L2 of the side cover part 42 is arranged at a position where the upper end is opposed to the lower surface of the battery lid 21 and the lower end is arranged at substantially the same position as the lowermost end of the curved part on the lower side of the wound electrode body 31. It is set to a length.

底面カバー部４３の突出長さＬ４は、捲回電極体３１の扁平厚さとほぼ同じ長さに設定されている。第１折り返し片４４の突出長さＬ５は、側面カバー部４２の扁平面対向部４２ｂの外側で電池缶１１の幅広側面ＰＷとの間に先端が介在される長さに設定されている。 The protruding length L4 of the bottom cover 43 is set to be substantially the same as the flat thickness of the wound electrode body 31. The protruding length L5 of the first folded piece 44 is set to a length at which the tip is interposed between the wide side surface PW of the battery can 11 outside the flat surface facing portion 42b of the side cover portion 42.

絶縁保護フィルム４１’の装着は、側面カバー部４２を捲回電極体３１の周囲に巻き付けて捲回電極体３１の側面を覆い、それから、底面カバー部４３を折りまげて捲回電極体３１の下側の湾曲部に対向配置し、さらに、第１折り返し片４４を折り返して扁平面対向部４２ｂの外側に対向配置することによって行われる。 The insulating protective film 41 ′ is attached by winding the side cover portion 42 around the wound electrode body 31 to cover the side surface of the wound electrode body 31, and then folding the bottom cover portion 43 to fold the wound electrode body 31. This is done by facing the lower curved portion and further by folding the first folded piece 44 so as to face the outside of the flat surface facing portion 42b.

上記構成によれば、扁平面対向部４２ｂの下端は、第１折り返し片４４によって外側から覆われているので、捲回電極体３１を電池缶１１に挿入する際に、電池缶１１の開口部１１ａに引っ掛かるおそれがなく、容易に挿入することができる。 According to the above configuration, since the lower end of the flat-plane facing portion 42 b is covered from the outside by the first folded piece 44, when the wound electrode body 31 is inserted into the battery can 11, the opening of the battery can 11 There is no fear of being caught by 11a, and it can be inserted easily.

側面カバー部４２は、捲回電極体３１の捲回軸方向両側の端面をすべて覆っており、電池缶１１との間における絶縁と保護を図っている。そして、捲回電極体３１の捲回軸方向両側の端面と電池缶１１の幅狭側面ＰＮとの間には、若干の隙間が形成されているので、側面カバー部４２の端面対向部４２ｃ、４２ｄの下端が折り返し片部によって覆われていなくても、電池缶１１に挿入する際に引っ掛かる可能性が低く、組立作業の阻害要因とはならない。したがって、第１実施の形態と比較して、絶縁保護フィルム４１’の全体形状を、より簡単にすることができ、製造の容易化、取り扱い性の向上等を図ることができる。 The side cover part 42 covers all the end faces on both sides in the winding axis direction of the wound electrode body 31, and insulates and protects the battery can 11. Since a slight gap is formed between the end surfaces on both sides in the winding axis direction of the wound electrode body 31 and the narrow side surface PN of the battery can 11, the end surface facing portion 42c of the side cover portion 42, Even if the lower end of 42d is not covered by the folded piece, it is unlikely to be caught when inserted into the battery can 11, and does not hinder assembly work. Therefore, as compared with the first embodiment, the overall shape of the insulating protective film 41 ′ can be simplified, and manufacturing can be facilitated and handling can be improved.

なお、本実施形態では、第２折り返し片４５を省略した構成の場合を例に説明したが、かかる構成に限定されるものではなく、電池缶１１の形状との関係において適宜変更することができ、例えば、第１折り返し片４４を省略して第２折り返し片４５のみとしてもよい。 In the present embodiment, the configuration in which the second folded piece 45 is omitted has been described as an example. However, the configuration is not limited to this configuration, and can be appropriately changed in relation to the shape of the battery can 11. For example, the first folded piece 44 may be omitted and only the second folded piece 45 may be provided.

以上、本発明の実施形態について詳述したが、本発明は、前記の実施形態に限定されるものではなく、特許請求の範囲に記載された本発明の精神を逸脱しない範囲で、種々の設計変更を行うことができるものである。例えば、前記した実施の形態は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、また、ある実施形態の構成に他の実施形態の構成を加えることも可能である。さらに、各実施形態の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

１リチウムイオン二次電池（角形電池）
２電池容器
３発電要素
４蓋組立体
５発電要素組立体
１１電池缶
１１ａ開口部
２１電池蓋
３１捲回電極体
４１絶縁保護フィルム
４２側面カバー部
４２ａ背面側の扁平面対向部（一方の扁平面対向部）
４２ｂ正面側の扁平面対向部（他方の扁平面対向部）
４２ｃ、４２ｄ端面対向部
４３底面カバー部
４４第１折り返し片（折り返し片部）
４５第２折り返し片（折り返し片部）
５１正極端子（電極端子）
５２、６２外部端子
５３、６３接続端子
５４、６４集電端子
６１負極端子（電極端子）
ＰＷ幅広側面
ＰＮ幅狭側面 1 Lithium ion secondary battery (square battery)
2 Battery container 3 Power generation element 4 Lid assembly 5 Power generation element assembly 11 Battery can 11a Opening part 21 Battery cover 31 Winding electrode body 41 Insulating protective film 42 Side cover part 42a Flat side facing part on the back side (one flat side) Opposite part)
42b The flat surface facing part on the front side (the other flat surface facing part)
42c, 42d End face facing portion 43 Bottom cover portion 44 First folded piece (folded piece portion)
45 Second folded piece (folded piece)
51 Positive terminal (electrode terminal)
52, 62 External terminals 53, 63 Connection terminals 54, 64 Current collecting terminal 61 Negative terminal (electrode terminal)
PW Wide side PN Narrow side

Claims

電極板を捲回して形成された扁平状の捲回電極体と、該捲回電極体の捲回軸方向が横向きで且つ前記捲回電極体の一対の湾曲部が上下に分かれて配置される姿勢状態の前記捲回電極体を収容し、前記捲回電極体を挿入可能な開口部が上部に設けられた有底の電池缶と、該電池缶と前記捲回電極体との間に介在される絶縁保護フィルムと、を有する角形電池であって、
前記絶縁保護フィルムは、
前記捲回電極体の扁平面に沿う方向でかつ前記捲回電極体の捲回軸方向に直交する方向を中心軸方向として前記捲回電極体の周囲に１周以上巻き付けられて前記捲回電極体の側面を覆う側面カバー部と、
該側面カバー部から突出して前記捲回電極体の下側の湾曲部を覆う底面カバー部と、
該底面カバー部から突出して前記捲回電極体の側面と前記電池缶の縦壁部との間に介在される折り返し片部と、
を有することを特徴とする角形電池。 A flat wound electrode body formed by winding an electrode plate, a winding axis direction of the wound electrode body is lateral, and a pair of curved portions of the wound electrode body are vertically divided. A bottomed battery can that accommodates the wound electrode body in a posture state and has an opening at the top where the wound electrode body can be inserted, and interposed between the battery can and the wound electrode body A square battery having an insulating protective film,
The insulating protective film is
The wound electrode is wound around the wound electrode body at least once around a direction along the flat plane of the wound electrode body and a direction perpendicular to the wound axis direction of the wound electrode body as a central axis direction. A side cover that covers the side of the body;
A bottom cover part that protrudes from the side cover part and covers the lower curved part of the wound electrode body;
A folded piece that protrudes from the bottom cover and is interposed between the side surface of the wound electrode body and the vertical wall of the battery can;
A prismatic battery comprising:

前記側面カバー部は、前記捲回電極体の扁平面に対向する一対の扁平面対向部と、前記捲回電極体の捲回軸方向両側の端面に対向する一対の端面対向部と、を有し、
前記底面カバー部は、前記捲回電極体の捲回軸方向の長さに亘って延在する幅と、一方の前記扁平面対向部の下端に基端が連続して先端が他方の前記扁平面対向部の下端までに亘る長さとを有する矩形状を有し、
前記折り返し片部は、前記底面カバー部の先端から突出して前記捲回電極体の扁平面と前記電池缶との間に介在される第１折り返し片と、前記底面カバー部の両側端から突出して前記捲回電極体の捲回軸方向両側の端面と前記電池缶との間に介在される一対の第２折り返し片との少なくとも一方を有することを特徴とする請求項１に記載の角形電池。 The side cover portion includes a pair of flat surface facing portions that face the flat surface of the wound electrode body and a pair of end surface facing portions that face end surfaces on both sides in the winding axis direction of the wound electrode body. And
The bottom cover portion has a width extending over the length of the wound electrode body in the winding axis direction, a bottom end of one flat surface facing portion, and a base end continuous to the other flat surface. It has a rectangular shape with a length extending to the lower end of the surface facing portion,
The folded piece portion protrudes from the front end of the bottom cover portion and protrudes from both sides of the bottom cover portion, a first folded piece interposed between the flat surface of the wound electrode body and the battery can. 2. The prismatic battery according to claim 1, comprising at least one of a pair of second folded pieces interposed between end faces on both sides in the winding axis direction of the wound electrode body and the battery can.

前記第１折り返し片は、前記側面カバー部の他方の扁平面対向部の外側に対向して配置され、
前記一対の第２折り返し片は、前記側面カバー部の一対の端面対向部の外側にそれぞれ対向して配置されていることを特徴とする請求項２に記載の角形電池。 The first folded piece is disposed to face the outside of the other flat surface facing portion of the side cover portion,
3. The prismatic battery according to claim 2, wherein the pair of second folded pieces are arranged to face the outside of the pair of end surface facing portions of the side surface cover portion.

前記底面カバー部は、前記捲回電極体の下側の湾曲部に沿って湾曲して配置されており、
前記第２折り返し片は、前記捲回電極体の側面に前記側面カバー部を巻き付けた状態で且つ前記捲回電極体を前記電池缶に挿入する前の状態において、前記底面カバー部の両側端から互いに離反する方向に突出して前記底面カバー部と共に湾曲していることを特徴とする請求項３に記載の角形電池。 The bottom cover part is arranged to be curved along a curved part on the lower side of the wound electrode body,
In the state where the side cover portion is wound around the side surface of the wound electrode body and before the wound electrode body is inserted into the battery can, the second folded piece is formed from both side ends of the bottom surface cover portion. The prismatic battery according to claim 3, wherein the prismatic battery protrudes in directions away from each other and is curved together with the bottom cover portion.

前記側面カバー部は、巻付方向一方側の端部と他方側の端部とが前記捲回電極体の扁平面に対向する位置で互いに重ね合わされることを特徴とする請求項１から請求項４のいずれか一項に記載の角形電池。 The said side surface cover part is mutually overlapped in the position where the edge part of one side of a winding direction and the edge part of the other side oppose the flat surface of the said winding electrode body. The prismatic battery according to any one of 4.

前記側面カバー部は、前記捲回電極体の扁平面に対向する位置で且つ捲回軸方向一方側に偏位した位置で互いに重ね合わされていることを特徴とする請求項５に記載の角形電池。 6. The rectangular battery according to claim 5, wherein the side cover portions are overlapped with each other at a position facing the flat surface of the wound electrode body and a position displaced to one side in the winding axis direction. .

請求項１に記載の角形電池の製造方法であって、
前記側面カバー部で前記捲回電極体の側面を覆う工程と、
前記底面カバー部で前記捲回電極体の下側の湾曲部を覆う工程と、
前記折り返し片部を前記側面カバー部の外側に対向配置する工程と、
前記絶縁保護フィルムで覆われた前記捲回電極体を前記電池缶の開口部から前記電池缶内に挿入する工程と、を含むことを特徴とする角形電池の製造方法。 It is a manufacturing method of the square battery according to claim 1,
Covering the side surface of the wound electrode body with the side surface cover portion;
Covering the lower curved portion of the wound electrode body with the bottom cover portion;
A step of opposingly arranging the folded piece portion outside the side surface cover portion;
And inserting the wound electrode body covered with the insulating protective film into the battery can through the opening of the battery can.