JP2013239313A - Lithium ion square secondary battery - Google Patents

Lithium ion square secondary battery Download PDF

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JP2013239313A
JP2013239313A JP2012110998A JP2012110998A JP2013239313A JP 2013239313 A JP2013239313 A JP 2013239313A JP 2012110998 A JP2012110998 A JP 2012110998A JP 2012110998 A JP2012110998 A JP 2012110998A JP 2013239313 A JP2013239313 A JP 2013239313A
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power generation
shaft core
generation element
secondary battery
lithium ion
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JP5802607B2 (en
JP2013239313A5 (en
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Yoshin Yagi
陽心 八木
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Vehicle Energy Japan Inc
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Hitachi Vehicle Energy 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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Abstract

PROBLEM TO BE SOLVED: To relieve the swelling of a battery container caused by expansion of a power generation element, without reducing the charge/discharge capacity of the battery.SOLUTION: An air gap 40S is formed between each circular arc portion 34 provided on both sides in the width direction (X direction) of an axis core 30 and an axis core portion 40A of a power generation element 40. A tip portion in the width direction of each circular arc portion 34 of the axis core 30 is stopped at a position more inside than a boundary face 40Z between a circular arc portion 40U and a flat portion 40Q in the axis core portion 40A. In other words, the air gap 40S extends over the regions of the circular arc portion 40U and the flat portion 40Q abutting on both sides of the boundary face 40Z. When the power generation element 40 expands in the thickness direction due to charge/discharge, the air gap 40S creates an escape use space for the expansion of the power generation element 40.

Description

この発明は、リチウムイオン角形二次電池に関し、より詳細には、軸芯の周囲に正・負極電極が捲回された扁平直方体状の発電要素を備えるリチウムイオン角形二次電池に関する。   The present invention relates to a lithium ion prismatic secondary battery, and more particularly to a lithium ion prismatic secondary battery including a flat rectangular parallelepiped power generation element in which positive and negative electrode electrodes are wound around an axis.

リチウムイオン角形二次電池は、正・負極電極が捲回された扁平直方体状の発電要素を備えている。
発電要素は、充放電の際のリチウムイオンの吸蔵・脱離により、正・負極電極が膨張・収縮する。発電要素が膨張すると、電池容器を押し広げ、電池容器の中央部が膨らむ。電池容器の膨らみは、電池収容スペースの拡大が必要となるため、電池容器の膨らみを緩和する対策が講じられている。 A lithium ion prismatic secondary battery includes a flat rectangular parallelepiped power generation element in which positive and negative electrodes are wound.
In the power generation element, positive and negative electrodes expand and contract due to insertion and extraction of lithium ions during charging and discharging. When the power generation element expands, the battery container is pushed out and the central part of the battery container expands. Since the expansion of the battery container requires expansion of the battery accommodation space, measures are taken to alleviate the expansion of the battery container.

そのような発電要素の作製方法の一例を以下に示す。先ず、円柱状の軸芯の周囲に、正・負極電極を所定の巻数回、捲回し、内周捲回体を形成する。この状態では、正・負極電極は、内周捲回体の最外周から、シート状に延出されている。次に、内周捲回体の外周に、軸芯より小径の円柱状スペーサを配置する。次に、内周捲回体の最外周から延出されている正・負極電極を、円柱状スペーサと内周捲回体の両方に跨るように捲回し、外周捲回体を形成する。次に、円柱状の軸芯を内周捲回体から引き抜いて、内周捲回体の捲回の中心部に円筒状の空隙部を形成する。   An example of a method for producing such a power generation element is shown below. First, the positive and negative electrodes are wound around the cylindrical shaft core by a predetermined number of turns to form an inner peripheral wound body. In this state, the positive / negative electrode is extended in a sheet form from the outermost periphery of the inner periphery wound body. Next, a columnar spacer having a diameter smaller than that of the shaft core is disposed on the outer periphery of the inner periphery wound body. Next, the positive and negative electrodes extended from the outermost periphery of the inner periphery wound body are wound so as to straddle both the columnar spacer and the inner periphery wound body, thereby forming the outer periphery wound body. Next, the columnar shaft core is pulled out from the inner peripheral wound body to form a cylindrical void at the center of the inner peripheral wound body.

次に、内周捲回体と外周捲回体をプレスし、扁平直方体状の発電要素を形成する。そして、最後に、円柱状スペーサを引き抜く。
このようにすることで、内周捲回体と、外周捲回体との間に、円柱状スペーサの径と同じ厚さの空隙部を有する発電要素が形成される（例えば、特許文献１参照）。この空隙部により、発電要素の膨張が緩和される。 Next, the inner peripheral wound body and the outer peripheral wound body are pressed to form a flat rectangular parallelepiped power generation element. Finally, the cylindrical spacer is pulled out.
By doing in this way, the electric power generation element which has the space | gap part of the same thickness as the diameter of a cylindrical spacer is formed between an inner periphery winding body and an outer periphery winding body (for example, refer patent document 1). ). The expansion of the power generation element is mitigated by the gap.

特開２００３−１５７８８８号公報JP 2003-157888 A

上記特許文献１に記載された発明では、内周捲回体と外周捲回体との間に、円柱状スペーサの径と同じ厚さの空隙を有する空隙部が形成される。このため、内周捲回体は、この空隙分、充放電面積が小さくなり、充放電の総容量が低下する。   In the invention described in Patent Document 1, a void portion having a void having the same thickness as the diameter of the columnar spacer is formed between the inner circumferential wound body and the outer circumferential wound body. For this reason, the inner winding body has a small charge and discharge area due to the gap, and the total capacity of charge and discharge is reduced.

本発明のリチウムイオン角形二次電池は、軸芯の周囲に、正極電極と負極電極とがセパレータを介して捲回され、扁平直方体状に形成された発電要素と、発電要素が収容され、電解液が注入された電池容器と、発電要素の正極電極に接続された外部正極端子と、発電要素の負極電極に接続された外部負極端子と、を備え、発電要素は、一対の平面部と、平面部の両側部に設けられた円弧部とにより扁平直方体状に形成された軸芯部を有し、軸芯部と軸芯との間には、少なくとも平面部と各円弧部との境界面に跨る領域を有する空隙部が設けられていることを特徴とする。   The lithium ion prismatic secondary battery of the present invention includes a power generation element formed in the shape of a flat rectangular parallelepiped by winding a positive electrode and a negative electrode around a shaft core via a separator, A battery case into which the liquid has been injected; an external positive terminal connected to the positive electrode of the power generation element; and an external negative terminal connected to the negative electrode of the power generation element. A shaft portion formed in a flat rectangular parallelepiped shape by arc portions provided on both sides of the plane portion, and a boundary surface between at least the plane portion and each arc portion between the shaft core portion and the shaft core It is characterized in that a void portion having a region extending over is provided.

この発明のリチウムイオン角形二次電池によれば、空隙となる領域が縮減されるので、総容量をほとんど低下することなく、電池容器の膨れを緩和することができる。   According to the lithium ion prismatic secondary battery of the present invention, since the void region is reduced, the swelling of the battery container can be alleviated without substantially reducing the total capacity.

本発明に係るリチウムイオン角形二次電池の一実施の形態の外観斜視図。1 is an external perspective view of an embodiment of a lithium ion prismatic secondary battery according to the present invention. 図１に示されたリチウムイオン角形二次電池の分解斜視図。FIG. 2 is an exploded perspective view of the lithium ion prismatic secondary battery shown in FIG. 1. 図２に図示された発電要素を、その捲回終端部側を展開した状態の斜視図。The perspective view of the state which expand | deployed the winding termination | terminus part side of the electric power generation element shown in FIG. 図３に図示された発電要素の拡大断面図。FIG. 4 is an enlarged cross-sectional view of the power generation element illustrated in FIG. 3. （ａ）は発電要素の軸芯の取付け状態を示す断面図、（ｂ）は図５（ａ）の領域Ｖｂの拡大図。(A) is sectional drawing which shows the attachment state of the axial center of an electric power generation element, (b) is an enlarged view of the area | region Vb of Fig.5 (a). 実施形態１の発電要素を作製する方法の説明するための図であり、発電要素の軸芯部に空隙部を形成する前の状態を示す断面図。It is a figure for demonstrating the method of producing the electric power generation element of Embodiment 1, and sectional drawing which shows the state before forming a space | gap part in the axial center part of an electric power generation element. 発電要素の軸芯部に空隙部を形成する方法を説明するための模式的平面図。The typical top view for demonstrating the method of forming a space | gap part in the axial center part of an electric power generation element. 従来の角形二次電池における電池容器の膨れを説明するための模式的断面図であり、（ａ）は充電前の図、（ｂ）は充電後の図。It is typical sectional drawing for demonstrating the swelling of the battery container in the conventional square secondary battery, (a) is the figure before charge, (b) is the figure after charge. 本発明の一実施の形態における電池容器の膨れを説明するための模式的断面図であり、（ａ）は充電前の図、（ｂ）は充電後の図。It is typical sectional drawing for demonstrating the swelling of the battery container in one embodiment of this invention, (a) is the figure before charge, (b) is the figure after charge. 本発明の実施形態２を示し、（ａ）は発電要素の軸芯の取付け状態を示す断面図、（ｂ）は図１０（ａ）の領域Ｘｂの拡大図。Embodiment 2 of this invention is shown, (a) is sectional drawing which shows the attachment state of the axial center of an electric power generation element, (b) is an enlarged view of the area | region Xb of Fig.10 (a). 実施形態２の発電要素を作製する方法の説明するための図であり、発電要素の軸芯部に空隙部を形成する前の状態を示す断面図。It is a figure for demonstrating the method of producing the electric power generation element of Embodiment 2, and sectional drawing which shows the state before forming a space | gap part in the axial center part of an electric power generation element.

-実施形態１-
［角形二次電池の全体構造］
以下、この発明のリチウムイオン角形二次電池の一実施形態を図面と共に説明する。
図１は、この発明のリチウムイオン角形二次電池の一実施の形態を示す外観斜視図であり、図２は、図１に示された角形二次電池の分解斜視図である。
リチウムイオン角形二次電池（以下、角形二次電池という）１は、電池蓋３および電池缶４とから構成される薄型のほぼ直方体形状の電池容器２内に、発電要素４０が収容され、図示はしないが非水電解液が注入されて構成されている。電池蓋３および電池缶４は、例えば、アルミニウムまたはアルミニウム合金等のアルミニウム系金属により形成されている。 -Embodiment 1-
[Overall structure of prismatic secondary battery]
Hereinafter, an embodiment of a lithium ion prismatic secondary battery of the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view showing an embodiment of a lithium ion prismatic secondary battery according to the present invention, and FIG. 2 is an exploded perspective view of the prismatic secondary battery shown in FIG.
A lithium ion prismatic secondary battery (hereinafter referred to as a prismatic secondary battery) 1 includes a power generation element 40 housed in a thin, substantially rectangular parallelepiped battery container 2 composed of a battery lid 3 and a battery can 4. Although not, it is configured by injecting a non-aqueous electrolyte. The battery lid 3 and the battery can 4 are made of an aluminum-based metal such as aluminum or an aluminum alloy, for example.

電池蓋３の中央部には、非水電解液を注入するための注液口１１が設けられている。注液口１１は、電解液注入後に注液栓１５により封口される。注液栓１５は、例えば、レーザ溶接によって電池蓋３の注液口１１の周縁部に接合される。
また、電池蓋３には、過充電等により内部圧力が上昇した際に、圧力を抜くための開裂弁１２が設けられている。開裂弁１２には、開裂用の溝１２ａが形成されている。
なお、本明細書においては、各図に図示されるように、角形二次電池１の幅方向をＸ方向、高さ方向をＹ方向、厚さ方向をＺ方向として説明する。 A liquid injection port 11 for injecting a non-aqueous electrolyte is provided at the center of the battery lid 3. The liquid injection port 11 is sealed with a liquid injection stopper 15 after the electrolytic solution is injected. The liquid injection plug 15 is joined to the peripheral edge portion of the liquid injection port 11 of the battery lid 3 by, for example, laser welding.
In addition, the battery lid 3 is provided with a cleavage valve 12 for releasing the pressure when the internal pressure rises due to overcharge or the like. The cleavage valve 12 has a cleavage groove 12a.
In the present specification, as shown in each drawing, the rectangular secondary battery 1 will be described with the width direction as the X direction, the height direction as the Y direction, and the thickness direction as the Z direction.

電池缶４内に注入される非水電解液としては、例えば、エチレンカーボネートとジメチルカーボネートとを体積比で１：２の割合で混合した混合溶液中へ六フッ化リン酸リチウム（ＬｉＰＦ６）を１モル／リットルの濃度で溶解したものを用いることができる。

有機溶媒としては、プロピレンカーボネート、エチレンカーボネート、１，２−ジメトキシエタン、１，２−ジエトキシエタン、γ−ブチロラクトン、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、プロピオニトニル等またはこれら２種類以上の混合溶媒を用いるようにしてもよく、混合配合比についても限定されるものではない。また、電解質としては、ＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＢＦ４、ＬｉＢ（Ｃ６Ｈ５）４、ＣＨ３ＳＯ３Ｌｉ、ＣＦ３ＳＯ３Ｌｉ等やこれらの混合物を用いることができる。したがって、一般的なリチウム塩を電解質とし、これを有機溶媒に溶解した非水電解液を用いるようにすればよく、本発明に用いられるリチウム塩や有機溶媒は特に制限されない。 As a non-aqueous electrolyte injected into the battery can 4, for example, lithium hexafluorophosphate (LiPF 6) is mixed into a mixed solution in which ethylene carbonate and dimethyl carbonate are mixed at a volume ratio of 1: 2. Those dissolved at a concentration of mol / liter can be used.

Examples of the organic solvent include propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether , Sulfolane, methylsulfolane, acetonitrile, propiontonyl, etc., or a mixed solvent of two or more of these may be used, and the mixing ratio is not limited. As the electrolyte, LiClO 4 , LiAsF 6 , LiBF 4 , LiB (C 6 H 5 ) 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, or the like, or a mixture thereof can be used. Accordingly, a non-aqueous electrolytic solution in which a general lithium salt is used as an electrolyte and dissolved in an organic solvent may be used, and the lithium salt and the organic solvent used in the present invention are not particularly limited.

電池蓋３には、正極側の端子構成部６０と負極側の端子構成部７０とが設けられている。
正極側の端子構成部６０は、外部正極端子６１、正極接続端子６２、正極端子板６３、絶縁部材６４および正極集電板２１を備えている。
正極集電板２１は、発電要素４０の正極電極４１（図３）に接合される接合部２１ａを有している。正極集電板２１は、電池蓋３の裏面側において、正極接続端子６２の下端部にかしめられている。正極接続端子６２は、電池蓋３に形成された貫通孔に挿通され、その上端部が電池蓋３の外部に露出されている。正極接続端子６２の上端部には、電池蓋３の上面に固定された正極端子板６３がかしめられている。 The battery lid 3 is provided with a positive terminal component 60 and a negative terminal component 70.
The terminal component 60 on the positive electrode side includes an external positive electrode terminal 61, a positive electrode connection terminal 62, a positive electrode terminal plate 63, an insulating member 64, and a positive electrode current collector plate 21.
The positive electrode current collector plate 21 has a joint portion 21 a that is joined to the positive electrode 41 (FIG. 3) of the power generation element 40. The positive electrode current collector plate 21 is caulked to the lower end portion of the positive electrode connection terminal 62 on the back surface side of the battery lid 3. The positive electrode connection terminal 62 is inserted into a through hole formed in the battery lid 3, and an upper end portion thereof is exposed to the outside of the battery lid 3. A positive electrode terminal plate 63 fixed to the upper surface of the battery lid 3 is caulked at the upper end of the positive electrode connection terminal 62.

絶縁部材６４は、正極端子板６３と電池蓋３との間に設けられ、正極端子板６３と電池蓋３とを絶縁する。絶縁部材６４は、また、電池蓋３の貫通孔と正極接続端子６２との間に介装されるリング状部を有し、電池蓋３と正極接続端子６２とを絶縁する。外部正極端子６１は、絶縁部材６４上に固定される基部（図示せず）を有し、軸部が正極端子板６３に設けられた貫通孔を貫通して、電池蓋３上に突き出している。
このように、外部正極端子６１、正極接続端子６２、正極端子板６３および正極集電板２１は、絶縁部材６４により電池蓋３とは電気的に絶縁された状態で、相互に電気的に接続されている。外部正極端子６１、正極接続端子６２、正極端子板６３および正極集電板２１は、例えば、アルミニウム、アルミニウム合金等のアルミニウム系金属により形成されている。 The insulating member 64 is provided between the positive terminal plate 63 and the battery lid 3 and insulates the positive terminal plate 63 and the battery lid 3. The insulating member 64 also has a ring-shaped portion interposed between the through hole of the battery lid 3 and the positive electrode connection terminal 62, and insulates the battery lid 3 and the positive electrode connection terminal 62. The external positive electrode terminal 61 has a base portion (not shown) fixed on the insulating member 64, and the shaft portion passes through a through hole provided in the positive electrode terminal plate 63 and projects onto the battery lid 3. .
Thus, the external positive electrode terminal 61, the positive electrode connection terminal 62, the positive electrode terminal plate 63, and the positive electrode current collector plate 21 are electrically connected to each other while being electrically insulated from the battery cover 3 by the insulating member 64. Has been. The external positive electrode terminal 61, the positive electrode connection terminal 62, the positive electrode terminal plate 63, and the positive electrode current collector plate 21 are made of, for example, an aluminum-based metal such as aluminum or an aluminum alloy.

負極側の端子構成部７０は、外部負極端子７１、負極接続端子７２、負極端子板７３、絶縁部材７４および負極集電板２２を備えている。
負極集電板２２は、発電要素４０の負極電極４２（図３）に接合される接合部２２ａを有している。負極集電板２２は、電池蓋３の裏面側において、負極接続端子７２の下端部にかしめられている。負極接続端子７２は、電池蓋３に形成された貫通孔に挿通され、その上端部が電池蓋３の外部に露出されている。負極接続端子７２の上端部には、電池蓋３の上面に固定された負極端子板７３がかしめられている。 The terminal component 70 on the negative electrode side includes an external negative electrode terminal 71, a negative electrode connection terminal 72, a negative electrode terminal plate 73, an insulating member 74, and a negative electrode current collector plate 22.
The negative electrode current collector plate 22 has a joint portion 22 a that is joined to the negative electrode 42 (FIG. 3) of the power generation element 40. The negative electrode current collector plate 22 is caulked to the lower end portion of the negative electrode connection terminal 72 on the back surface side of the battery lid 3. The negative electrode connection terminal 72 is inserted through a through hole formed in the battery lid 3, and an upper end portion thereof is exposed to the outside of the battery lid 3. A negative electrode terminal plate 73 fixed to the upper surface of the battery lid 3 is caulked at the upper end portion of the negative electrode connection terminal 72.

絶縁部材７４は、負極端子板７３と電池蓋３との間に設けられ、負極端子板７３と電池蓋３とを絶縁する。絶縁部材７４は、また、電池蓋３の貫通孔と負極接続端子７２との間に介装されるリング状部を有し、電池蓋３と負極接続端子７２とを絶縁する。外部負極端子７１は、絶縁部材７４上に固定される基部（図示せず）を有し、軸部が負極端子板７３に設けられた貫通孔を貫通して、電池蓋３上に突き出している。
このように、外部負極端子７１、負極接続端子７２、負極端子板７３および負極集電板２２は、絶縁部材７４により電池蓋３とは電気的に絶縁された状態で、相互に電気的に接続されている。外部負極端子７１、負極接続端子７２、負極端子板７３および負極集電板２２は、例えば、銅、銅合金等の銅系金属により形成されている。 The insulating member 74 is provided between the negative electrode terminal plate 73 and the battery lid 3 and insulates the negative electrode terminal plate 73 from the battery lid 3. The insulating member 74 also has a ring-shaped portion interposed between the through hole of the battery lid 3 and the negative electrode connection terminal 72, and insulates the battery lid 3 and the negative electrode connection terminal 72. The external negative electrode terminal 71 has a base (not shown) fixed on the insulating member 74, and the shaft portion passes through a through hole provided in the negative electrode terminal plate 73 and protrudes onto the battery lid 3. .
Thus, the external negative electrode terminal 71, the negative electrode connection terminal 72, the negative electrode terminal plate 73, and the negative electrode current collector plate 22 are electrically connected to each other while being electrically insulated from the battery lid 3 by the insulating member 74. Has been. The external negative electrode terminal 71, the negative electrode connection terminal 72, the negative electrode terminal plate 73, and the negative electrode current collector plate 22 are made of, for example, a copper-based metal such as copper or a copper alloy.

発電要素４０は、正極側では、捲回により積層状態とされた正極合剤未塗工部４１ｃ（図３）が正極集電板２１の接合部２１ａに接合され、負極側では、捲回により積層状態とされた負極合剤未塗工部４２ｃ（図３）が負極集電板２２の接合部２２ａに接合される。接合は、例えば、超音波溶接等により行われ、これにより、正極側の端子構成部６０、負極側の端子構成部７０と発電要素４０とが、電池蓋３に一体化された電池蓋・発電要素ユニットが形成される。   In the power generation element 40, on the positive electrode side, the positive electrode mixture uncoated portion 41c (FIG. 3), which has been laminated by winding, is bonded to the bonding portion 21a of the positive electrode current collector plate 21, and on the negative electrode side, by winding. The negative electrode mixture uncoated portion 42 c (FIG. 3) in a laminated state is bonded to the bonding portion 22 a of the negative electrode current collector plate 22. The joining is performed by, for example, ultrasonic welding or the like, whereby the positive terminal component 60, the negative terminal component 70, and the power generation element 40 are integrated with the battery cover 3. Element units are formed.

電池缶４は、電池蓋３側に開口部を有する薄箱型に形成されている。電池缶４には、絶縁袋５が収納されている。絶縁袋５の電池蓋３側には開口部５ａが形成されている。
発電要素４０は、電池蓋３に一体化された電池蓋・発電要素ユニットの状態で、絶縁袋５の開口部５ａから、絶縁袋５内に収容される。電池缶４の開口部は、電池蓋３により、その開口部が閉塞される。電池蓋３の周縁部３ａは薄肉とされており、この周縁部３ａを電池缶４の開口部の周縁部に嵌合した状態で、例えば、レーザ溶接によって電池缶４に接合され、外部に対し密封構造とされる。 The battery can 4 is formed in a thin box shape having an opening on the battery lid 3 side. The battery can 4 contains an insulating bag 5. An opening 5 a is formed on the battery lid 3 side of the insulating bag 5.
The power generation element 40 is accommodated in the insulating bag 5 through the opening 5 a of the insulating bag 5 in a state of a battery lid / power generating element unit integrated with the battery cover 3. The opening of the battery can 4 is closed by the battery lid 3. The peripheral edge 3a of the battery lid 3 is thin, and the peripheral edge 3a is fitted to the peripheral edge of the opening of the battery can 4, and is joined to the battery can 4 by laser welding, for example, to the outside. It is a sealed structure.

図３は、図２に図示された発電要素の詳細を説明するための斜視図であり、図４は、図３に図示された発電要素の拡大断面図である。なお、図３においては、発電要素４０の捲回終端部側を展開した状態として示している。
発電要素４０は、正極電極４１と負極電極４２とを、第１、第２のセパレータ４３、４４を介在して軸芯３０の周りに捲回して、扁平直方体状に形成されたものである。
正極電極４１は、例えば、アルミニウムまたはアルミニウム合金等のアルミニウム系金属からなる正極金属シート４１ａの表裏両面に正極合剤が塗工された正極合剤塗工部４１ｂを有する。正極合剤塗工部４１ｂは、正極金属シート４１ａの一側縁に、正極金属シート４１ａが露出された正極合剤未塗工部４１ｃが形成されるように正極金属シート４１ａに正極合剤を塗工して形成される。
負極電極４２は、例えば、銅または銅合金等の銅系金属からなる負極金属シート４２ａの表裏両面に負極合剤が塗工された負極合剤塗工部４２ｂを有する。負極合剤塗工部４２ｂは、負極合剤未塗工部４２ｃが配置された側縁と対向する側縁である他側縁に、負極金属シート４２ａが露出された負極合剤未塗工部４２ｃが形成されるように負極金属シート４２ａに負極合剤を塗工して形成される。 3 is a perspective view for explaining the details of the power generation element shown in FIG. 2, and FIG. 4 is an enlarged cross-sectional view of the power generation element shown in FIG. In FIG. 3, the winding end portion side of the power generation element 40 is shown in a developed state.
The power generation element 40 is formed into a flat rectangular parallelepiped shape by winding the positive electrode 41 and the negative electrode 42 around the shaft core 30 with the first and second separators 43 and 44 interposed therebetween.
The positive electrode 41 has, for example, a positive electrode mixture coating portion 41b in which a positive electrode mixture is coated on both front and back surfaces of a positive electrode metal sheet 41a made of an aluminum-based metal such as aluminum or an aluminum alloy. The positive electrode mixture coating portion 41b applies a positive electrode mixture to the positive electrode metal sheet 41a so that a positive electrode mixture uncoated portion 41c where the positive electrode metal sheet 41a is exposed is formed on one side edge of the positive electrode metal sheet 41a. It is formed by coating.
The negative electrode 42 includes, for example, a negative electrode mixture coating portion 42b in which a negative electrode mixture is coated on both front and back surfaces of a negative electrode metal sheet 42a made of copper-based metal such as copper or a copper alloy. The negative electrode mixture coated portion 42b is a negative electrode mixture uncoated portion in which the negative electrode metal sheet 42a is exposed on the other side edge that is the side edge opposite to the side edge where the negative electrode mixture uncoated portion 42c is disposed. The negative electrode metal sheet 42a is coated with a negative electrode mixture so that 42c is formed.

正極合剤塗工部４１ｂは、正極活物質としてリチウム含有複合酸化物粉末と、導電材として鱗片状黒鉛と、結着剤としてポリフッ化ビニリデン（ＰＶＤＦ）とを重量比９０：６．５：３．５で混合し、これに分散溶媒であるＮ−メチルピロリドン（ＮＭＰ）を添加、混練したスラリを作成し、厚さ１５μｍのアルミニウム箔の両面に塗布して作製される。その後、乾燥、プレス、裁断することにより活物質合剤層が配された部分の幅１３０ｍｍ、厚さ１４０μｍの正極電極４１が形成される。   The positive electrode mixture coating part 41b has a weight ratio of 90: 6.5: 3 of a lithium-containing composite oxide powder as a positive electrode active material, scaly graphite as a conductive material, and polyvinylidene fluoride (PVDF) as a binder. 5 and mixed with N-methylpyrrolidone (NMP) as a dispersion solvent, and a kneaded slurry is prepared and applied to both surfaces of an aluminum foil having a thickness of 15 μm. Thereafter, drying, pressing, and cutting form the positive electrode 41 having a width of 130 mm and a thickness of 140 μm at the portion where the active material mixture layer is disposed.

負極合剤塗工部４２ｂは、負極活物質としての黒鉛粉末と、結着剤としてのスチレンブタジエンゴム（ＳＢＲ）、増粘材としてカルボキシメチルセルロース（ＣＭＣ）を重量比９８：１：１で混合し、これに分散溶媒の水を添加し、混練して得られたスラリを、厚さ１０μｍの圧延銅箔の両面に塗布して作製される。その後、乾燥プレス、裁断することにより活物質合剤層が配された部分の幅１３４ｍｍ、厚さ１４０μｍの負極電極４２が形成される。   The negative electrode mixture coating part 42b mixes graphite powder as a negative electrode active material, styrene butadiene rubber (SBR) as a binder, and carboxymethyl cellulose (CMC) as a thickener at a weight ratio of 98: 1: 1. The slurry obtained by adding water as a dispersion solvent and kneading to this is applied to both surfaces of a rolled copper foil having a thickness of 10 μm. Thereafter, the negative electrode 42 having a width of 134 mm and a thickness of 140 μm is formed by dry pressing and cutting.

なお、上記において、正極バインダとしてＰＶＤＦを、負極バインダとしてＳＢＲを例示したが、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、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等の重合体及びこれらの混合体などを使用するようにしてもよい。   In the above, PVDF is exemplified as the positive electrode binder and SBR is exemplified as the negative electrode binder. However, polytetrafluoroethylene (PTFE), polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various types Polymers such as latex, acrylonitrile, vinyl fluoride, vinylidene fluoride, propylene fluoride, chloroprene fluoride, and mixtures thereof may be used.

セパレータ４３、４４は、正極金属シート４１ａまたは負極金属シート４２ａを絶縁する役割を有している。負極電極４２の負極合剤塗工部４２ｂは、正極電極４１の正極合剤塗工部４１ｂよりも幅方向（Ｘ方向）に大きく形成され、これにより正極合剤塗工部４１ｂは、必ず負極合剤塗工部４２ｂに挟まれるように構成されている。
発電要素４０は、図３に示すように、最外周の電極が負極電極４２とされ、さらにその外側にセパレータ４４が捲回される。 The separators 43 and 44 have a role of insulating the positive electrode metal sheet 41a or the negative electrode metal sheet 42a. The negative electrode mixture coating portion 42b of the negative electrode 42 is formed larger in the width direction (X direction) than the positive electrode mixture coating portion 41b of the positive electrode 41, so that the positive electrode mixture coating portion 41b is always a negative electrode It is comprised so that it may be pinched | interposed into the mixture coating part 42b.
As shown in FIG. 3, the power generation element 40 has an outermost electrode as a negative electrode 42 and a separator 44 wound around the negative electrode 42.

図３、図４に図示されるように、発電要素４０の外形形状は、捲回方向（Ｙ方向）の両側部に形成された円弧部４０Ｔと、両円弧部４０Ｔの間に位置する平坦部４０Ｐとにより形成される扁平直方体状である。
発電要素４０は、軸芯３０を保持する軸芯部４０Ａを備えている。詳細は後述するが、発電要素４０は、軸芯３０および軸心３０の高さ方向（Ｙ方向）における両側部側に配置されたスペーサ５３（図７）の周囲に、負極電極４２、セパレータ４４、正極電極４１およびセパレータ４３を積層して、Ｙ方向に捲回して作製される。軸芯部４０Ａは、軸芯３０およびスペーサ５３の周囲に捲回される発電要素４０の内面に囲まれる領域を指す。従って、軸芯部４０Ａは、捲回の中心部に位置する。換言すれば、軸芯部４０Ａは、その中心軸が発電要素４０の厚さ方向（Ｚ方向）および高さ方向（Ｙ方向）のほぼ中心に位置する。 As illustrated in FIGS. 3 and 4, the outer shape of the power generation element 40 is an arc portion 40T formed on both side portions in the winding direction (Y direction) and a flat portion located between both arc portions 40T. It is a flat rectangular parallelepiped shape formed by 40P.
The power generation element 40 includes a shaft core portion 40 </ b> A that holds the shaft core 30. As will be described in detail later, the power generation element 40 includes a negative electrode 42 and a separator 44 around spacers 53 (FIG. 7) disposed on both sides in the height direction (Y direction) of the shaft core 30 and the shaft center 30. The positive electrode 41 and the separator 43 are stacked and wound in the Y direction. The shaft core portion 40 </ b> A refers to a region surrounded by the inner surface of the power generation element 40 wound around the shaft core 30 and the spacer 53. Therefore, the shaft core portion 40A is located at the center of winding. In other words, the shaft core portion 40 </ b> A has a central axis positioned substantially at the center in the thickness direction (Z direction) and the height direction (Y direction) of the power generation element 40.

軸芯３０は、全体がほぼ平坦な板状部材であり、中央の矩形部３１の幅方向（Ｘ方向）における両側端に、正・負極電極４１、４２の各側端から突き出す一対の突出片３２が形成されている。また、軸芯３０のＹ方向における両側部には、円弧部３４（図４参照）が形成されている。   The shaft core 30 is a plate member that is substantially flat as a whole, and a pair of projecting pieces that project from the side ends of the positive and negative electrode electrodes 41 and 42 at both side ends in the width direction (X direction) of the central rectangular portion 31. 32 is formed. Moreover, the circular arc part 34 (refer FIG. 4) is formed in the both sides in the Y direction of the axial center 30. As shown in FIG.

図５（ａ）は発電要素の軸芯の取付け状態を示す断面図であり、図５（ｂ）は図５（ａ）の領域Ｖｂの拡大図である。
発電要素４０の軸芯部４０Ａは、外形形状に倣って、高さ方向（Ｙ方向）の両側部に形成された円弧部４０Ｕと、両円弧部４０Ｕの間に位置する平坦部４０Ｑとにより形成される扁平直方体形状を有する。各円弧部４０Ｕは、断面が半円形であり、円弧部４０Ｕと平坦部４０Ｑの境界面４０Ｚは、円弧部４０Ｕの中心を通り、平坦部４０Ｑに垂直な面となっている。 Fig.5 (a) is sectional drawing which shows the attachment state of the axial center of an electric power generation element, FIG.5 (b) is an enlarged view of the area | region Vb of Fig.5 (a).
The axial core portion 40A of the power generation element 40 is formed by an arc portion 40U formed on both side portions in the height direction (Y direction) and a flat portion 40Q positioned between both arc portions 40U following the outer shape. It has a flat rectangular parallelepiped shape. Each arc portion 40U has a semicircular cross section, and a boundary surface 40Z between the arc portion 40U and the flat portion 40Q passes through the center of the arc portion 40U and is a surface perpendicular to the flat portion 40Q.

軸芯３０の各円弧部３４と発電要素４０の軸芯部４０Ａとの間には、空隙部４０Ｓが形成されている。軸芯３０の各円弧部３４のＹ方向における先端部は、軸芯部４０Ａにおける円弧部４０Ｕと平坦部４０Ｑの境界面４０Ｚよりも内方に位置している。すなわち、軸芯３０の円弧部３４の外方は、空隙部４０Ｓとなっている。このように、空隙部４０Ｓは、境界面４０Ｚの両側に隣接する円弧部４０Ｕおよび平坦部４０Ｑの領域に跨っている。
後述する如く、この空隙部４０Ｓによって、角形二次電池１を充放電した際の角形二次電池１の厚さ方向（Ｚ方向）の膨れが緩和される。
次に、このような空隙部４０Ｓを有する軸芯部４０Ａを備えた発電要素の製造方法を説明する。 A gap 40S is formed between each arc 34 of the shaft 30 and the shaft 40A of the power generation element 40. The tip end portion in the Y direction of each arc portion 34 of the shaft core 30 is located inward of the boundary surface 40Z between the arc portion 40U and the flat portion 40Q in the shaft core portion 40A. That is, the outer side of the arc portion 34 of the shaft core 30 is a gap portion 40S. Thus, the gap 40S straddles the regions of the arc 40U and the flat portion 40Q adjacent to both sides of the boundary surface 40Z.
As will be described later, the gap 40S reduces swelling in the thickness direction (Z direction) of the prismatic secondary battery 1 when the prismatic secondary battery 1 is charged and discharged.
Next, the manufacturing method of the electric power generation element provided with the axial core part 40A which has such a space | gap part 40S is demonstrated.

図６は、発電要素の軸芯部に空隙部を形成する前の状態を示す断面図であり、図７は、発電要素の軸芯部に空隙部を形成する方法を説明するための模式的平面図である。
図７に図示されるように、捲回装置５１には、軸芯３０の突出片３２を嵌合する溝５２が設けられ、また、溝５２の両側に、平行に延在された一対のスペーサ５３が植立されている。各スペーサ５３は、空隙部４０Ｓを形成するためのもので、空隙部４０Ｓの厚さと同じ厚さの長い薄板形状を有する。図６に図示されるように、スペーサ５３の内側部は、軸芯３０の円弧部３４の側面に対応する円弧状に形成され、外側部は空隙部４０Ｓの円弧部４０Ｕ（図５参照）に対応する円弧状に形成されている。 FIG. 6 is a cross-sectional view showing a state before the gap is formed in the shaft core portion of the power generation element, and FIG. 7 is a schematic diagram for explaining a method of forming the gap portion in the shaft core portion of the power generation element. It is a top view.
As shown in FIG. 7, the winding device 51 is provided with a groove 52 for fitting the protruding piece 32 of the shaft core 30, and a pair of spacers extending in parallel on both sides of the groove 52. 53 are planted. Each spacer 53 is for forming the gap 40S, and has a long thin plate shape with the same thickness as the gap 40S. As shown in FIG. 6, the inner portion of the spacer 53 is formed in an arc shape corresponding to the side surface of the arc portion 34 of the shaft core 30, and the outer portion is an arc portion 40U (see FIG. 5) of the gap portion 40S. Corresponding arcs are formed.

捲回装置５１の溝５２に、軸芯３０の突出片３２を嵌入すると、図６に図示されるように、軸芯３０のＸ方向における両側部に隣接して、それぞれ、スペーサ５３が配置される。この状態で、軸芯３０および一対のスペーサ５３の周囲に、負極電極４２、セパレータ４４、正極電極４１およびセパレータ４３を積層して、捲回する。これにより、図６に図示されたスペーサ５３を備える発電要素４０が作製される。捲回に際しては、負極電極４２、セパレータ４４、正極電極４１およびセパレータ４３に、シート長手方向に、例えば、１０Ｎ程度の荷重をかけて伸展しながら行う。
この後、図５に図示されるように、発電要素４０を、スペーサ５３から引出すことにより、図５に図示される発電要素４０を得ることができる。 When the protruding piece 32 of the shaft core 30 is inserted into the groove 52 of the winding device 51, the spacers 53 are respectively arranged adjacent to both side portions in the X direction of the shaft core 30 as shown in FIG. The In this state, the negative electrode 42, the separator 44, the positive electrode 41, and the separator 43 are laminated around the shaft core 30 and the pair of spacers 53 and wound. Thereby, the electric power generation element 40 provided with the spacer 53 illustrated in FIG. 6 is manufactured. The winding is performed while the negative electrode 42, the separator 44, the positive electrode 41, and the separator 43 are stretched by applying a load of about 10 N, for example, in the longitudinal direction of the sheet.
Thereafter, as illustrated in FIG. 5, the power generation element 40 illustrated in FIG. 5 can be obtained by pulling out the power generation element 40 from the spacer 53.

次に、発電要素４０に形成された空隙部４０Ｓの作用を説明する。
図８は、従来の角形二次電池における電池容器の膨れを説明するための模式的断面図であり、図８（ａ）は充電前の図、図８（ｂ）は充電後の図である。
図８（ａ）、８（ｂ）に図示されるように、従来では、発電要素１４０の軸芯部１４０Ａと軸芯１３０との間には、空隙部は存在していなかった。
リチウム角形二次電池が充放電されると、リチウムイオンの吸蔵・脱離によって、発電要素１４０が厚さ方向（Ｚ方向）に膨張する。正極活物質及び負極活物質の材料により、充電時に膨張し、放電時に収縮する場合と、逆に、充電時に収縮し、放電時に膨張する場合があるが、いずれにしても、充放電により厚さ方向への膨張・収縮が生じる。 Next, the operation of the gap 40S formed in the power generation element 40 will be described.
FIG. 8 is a schematic cross-sectional view for explaining the swelling of the battery case in the conventional prismatic secondary battery, FIG. 8 (a) is a diagram before charging, and FIG. 8 (b) is a diagram after charging. .
As illustrated in FIGS. 8A and 8B, conventionally, there is no gap between the shaft core portion 140 </ b> A and the shaft core 130 of the power generation element 140.
When the lithium prismatic secondary battery is charged and discharged, the power generation element 140 expands in the thickness direction (Z direction) due to insertion and extraction of lithium ions. Depending on the material of the positive electrode active material and the negative electrode active material, it may expand during charging and contract during discharging, and conversely, it contracts during charging and may expand during discharging. Expansion and contraction in the direction occur.

発電要素１４０が膨張すると、軸芯部１４０Ａの円弧部１４０Ｕと平坦部１４０Ｑの境界面１４０Ｚが、作用点となって電池缶４を押し広げる。図８（ｂ）において、境界面１４０Ｚ上に図示された矢印が作用点である。このため、電池缶４の長辺側の側部は、発電要素１４０により、図示の如く、外側に向けて弓形に膨れる。このとき、高さ方向（Ｙ方向）における作用点の間隔をｘ１とする。電池缶４の膨れの最大部分は、電池缶４の強度が全体に亘りほぼ等しい場合には、幅方向における作用点の間隔ｘ１の中央部付近となる。 When the power generation element 140 expands, the arc 140 </ b> U of the shaft core 140 </ b> A and the boundary surface 140 </ b> Z between the flat part 140 </ b> Q act as an action point to push the battery can 4. In FIG. 8B, an arrow shown on the boundary surface 140Z is an action point. For this reason, the side part of the long side of the battery can 4 swells in an arcuate shape toward the outside as shown in the figure by the power generation element 140. At this time, the distance between the action point in the height direction (Y direction) x 1. The largest part of the expansion of the battery can 4, when the intensity of the battery can 4 is substantially equal over the whole, the vicinity of the center of the interval x 1 of the point in the width direction.

図９は、本発明の一実施の形態における電池容器の膨れを説明するための模式的断面図であり、図９（ａ）は充電前の図、図９（ｂ）は充電後の図である。
上述した如く、本発明の一実施の形態として示した発電要素４０は、図８（ａ）に示す充電前の状態において、高さ方向（Ｙ方向）における軸芯部４０Ａと軸芯３０との間に、空隙部４０Ｓが形成されている。 9A and 9B are schematic cross-sectional views for explaining the swelling of the battery container according to the embodiment of the present invention. FIG. 9A is a diagram before charging, and FIG. 9B is a diagram after charging. is there.
As described above, the power generation element 40 shown as an embodiment of the present invention has the shaft core portion 40A and the shaft core 30 in the height direction (Y direction) in the state before charging shown in FIG. A gap 40S is formed between them.

上述した如く、空隙部４０Ｓは、境界面４０Ｚと、この境界面４０Ｚの両側に隣接する円弧部４０Ｕおよび平坦部４０Ｑの領域を含んでいる。このような空隙部４０Ｓが存在するため、充放電により、発電要素４０が厚さ方向に膨張すると、電池缶４の反力により、空隙部４０Ｓが押し潰される。つまり、空隙部４０Ｓは、発電要素４０の膨張時の逃げ用の空間となる。
本発明の一実施の形態と示す角形二次電池１の場合においては、発電要素４０が膨張した場合、図９（ｂ）の矢印に図示されるように、軸芯３０の円弧部３４と矩形部３１の境界面３０Ｚが、電池缶４を押し広げる作用点となる。 As described above, the gap 40S includes the boundary surface 40Z and the regions of the arc portion 40U and the flat portion 40Q adjacent to both sides of the boundary surface 40Z. Since such a gap 40S exists, when the power generation element 40 expands in the thickness direction due to charge / discharge, the gap 40S is crushed by the reaction force of the battery can 4. That is, the gap 40 </ b> S serves as a space for escape when the power generation element 40 is expanded.
In the case of the prismatic secondary battery 1 shown as one embodiment of the present invention, when the power generation element 40 expands, as shown by the arrow in FIG. The boundary surface 30 </ b> Z of the portion 31 serves as an action point that spreads the battery can 4.

図９（ｂ）において、軸芯部４０Ａの高さ方向（Ｙ方向）両側端に形成された円弧部４０Ｕと平坦部４０Ｑとの境界面４０Ｚ間の間隔ｘ１は、図８（ｂ）に図示された、軸芯部１４０Ａの円弧部１４０Ｕと平坦部１４０Ｑの境界面１４０Ｚ間の間隔ｘ１と同一である。
本発明の一実施の形態に示すように、軸芯部４０Ａの両端に空隙部４０Ｓがある場合には、軸芯３０の円弧部３４と矩形部３１との境界面３０Ｚが、電池缶４を押し広げる作用点となる。
従って、Ｙ方向における軸芯３０の円弧部３４と矩形部３１の境界面３０Ｚの間隔ｘ２は、図８（ｂ）における間隔ｘ１よりも小さい。
上述した如く、電池缶４の長辺側の側部は、Ｙ方向における２つの作用点に挟まれた間隔ｘ２の部分が、外側に向けて弓形に変形する。このため、発電要素４０の膨張による電池缶４を押し広げる力が緩和され、電池缶４の膨れが低減する。 In FIG. 9B, an interval x1 between the boundary surface 40Z between the arc portion 40U and the flat portion 40Q formed at both ends in the height direction (Y direction) of the shaft core portion 40A is illustrated in FIG. 8B. It has been the same as the distance x 1 between the boundary surfaces 140Z arcuate section 140U and the flat portion 140Q of the shaft portion 140A.
As shown in the embodiment of the present invention, when there is a gap 40S at both ends of the shaft core portion 40A, the boundary surface 30Z between the arc portion 34 and the rectangular portion 31 of the shaft core 30 defines the battery can 4. It becomes the point of action to spread.
Therefore, the interval x 2 of the boundary surface 30Z of the arcuate portion 34 and rectangular portion 31 of the axial core 30 in the Y direction is smaller than the distance x 1 in FIG. 8 (b).
As described above, in the side portion on the long side of the battery can 4, the portion of the interval x 2 sandwiched between the two action points in the Y direction is deformed into an arcuate shape toward the outside. For this reason, the force which pushes the battery can 4 by expansion | swelling of the electric power generation element 40 is relieve | moderated, and the swelling of the battery can 4 reduces.

図４および図９において、空隙部４０Ｓを発電要素４０の中心軸に対し左右対称形状とすると、電池缶４の膨れが中心軸に対して対称となるので、角形二次電池１を設置したり、電池モジュールを作製したりする際の取り扱いが容易となる。
各空隙部４０Ｓにおける高さ方向（Ｙ方向）の長さには、特に、制限はない。但し、余り空隙部４０Ｓの幅方向の長さを大きくすると、電池缶４の膨れを緩和する量が小さくなる。従って、各空隙部４０Ｓの幅方向の長さは、軸芯部４０ＡのＹ方向の全長の１/５〜１/４程度を最大とすることが好ましい。 4 and 9, when the gap 40S is symmetrical with respect to the central axis of the power generating element 40, the swelling of the battery can 4 is symmetric with respect to the central axis. The battery module can be easily handled.
The length in the height direction (Y direction) in each gap 40S is not particularly limited. However, if the length of the gap 40S in the width direction is increased, the amount for reducing the swelling of the battery can 4 decreases. Therefore, it is preferable that the length in the width direction of each gap portion 40S is about 1/5 to 1/4 of the total length in the Y direction of the shaft core portion 40A.

-実施形態２-
本発明によるリチウムイオン角形二次電池１の実施形態２について説明する。
図１０（ａ）は、実施形態２としての発電要素の軸芯の取付け状態を示す断面図であり、図１０（ｂ）は、図１０（ａ）の領域Ｘｂの拡大図である。また、図１１は、発電要素の軸芯部に空隙部を形成する前の状態を示す断面図である。
実施形態１では、軸芯３０の各円弧部３４の高さ方向（Ｙ方向）における先端部は、軸芯部４０Ａにおける円弧部４０Ｕと平坦部４０Ｑの境界面４０Ｚよりも内方に位置していた。換言すれば、軸芯３０の先端部よりも外側に位置する空隙部４０Ｓは、軸芯部４０Ａの厚さ全体に亘って形成されていた。 Embodiment 2
Embodiment 2 of the lithium ion prismatic secondary battery 1 according to the present invention will be described.
Fig.10 (a) is sectional drawing which shows the attachment state of the axial center of the electric power generation element as Embodiment 2, FIG.10 (b) is an enlarged view of the area | region Xb of Fig.10 (a). FIG. 11 is a cross-sectional view showing a state before a gap is formed in the axial core portion of the power generation element.
In the first embodiment, the tip end portion in the height direction (Y direction) of each arc portion 34 of the shaft core 30 is located inward of the boundary surface 40Z between the arc portion 40U and the flat portion 40Q in the shaft core portion 40A. It was. In other words, the gap portion 40S located outside the tip end portion of the shaft core 30 is formed over the entire thickness of the shaft core portion 40A.

これに対し、実施形態２では、軸芯３０Ａの高さ方向（Ｙ方向）における先端部は、軸芯部４０Ａにおける円弧部４０Ｕと平坦部４０Ｑの境界面４０Ｚを超えて張り出している。
図１０（ｂ）に図示されるように、軸芯３０Ａの高さ方向（Ｙ方向）における両側部は、先細に湾曲する半楕円部３４ａとされている。半楕円部３４ａの幅方向における先端部は、軸芯部４０Ａの円弧部４０Ｕの幅方向における端部に実質的に接している。
これにより、実施形態２では、上部空隙部４０Ｓ１と下部空隙部４０Ｓ２に２分割されている。 On the other hand, in the second embodiment, the tip portion in the height direction (Y direction) of the shaft core 30A protrudes beyond the boundary surface 40Z between the arc portion 40U and the flat portion 40Q in the shaft core portion 40A.
As shown in FIG. 10B, both side portions in the height direction (Y direction) of the shaft core 30A are semi-elliptical portions 34a that are tapered. The tip end portion in the width direction of the semi-elliptical portion 34a is substantially in contact with the end portion in the width direction of the arc portion 40U of the shaft core portion 40A.
Thus, in the second embodiment, the upper gap 40S1 and the lower gap 40S2 are divided into two.

上部空隙部４０Ｓ１及び下部空隙部４０Ｓ２は、それぞれ、軸芯部４０Ａにおける円弧部４０Ｕと平坦部４０Ｑの境界面４０Ｚを含み、この境界面４０Ｚに隣接する平坦部４０Ｑと円弧部４０Ｕの領域に跨っている。上述した如く、境界面４０Ｚが、電池缶４を押し広げる作用点となるため、上部空隙部４０Ｓ１および下部空隙部４０Ｓ２は、膨張する発電要素４０の逃げ用の空間となる。したがって、このような構造においても、発電要素４０の膨張による電池缶４の膨れを緩和することができる。   The upper gap portion 40S1 and the lower gap portion 40S2 each include a boundary surface 40Z between the arc portion 40U and the flat portion 40Q in the shaft core portion 40A, and straddle the regions of the flat portion 40Q and the arc portion 40U adjacent to the boundary surface 40Z. ing. As described above, since the boundary surface 40Z serves as an action point for pushing the battery can 4 apart, the upper gap portion 40S1 and the lower gap portion 40S2 become a space for escaping the expanding power generation element 40. Therefore, even in such a structure, the expansion of the battery can 4 due to the expansion of the power generation element 40 can be reduced.

上部空隙部４０Ｓ１および下部空隙部４０Ｓ２を有する発電要素４０を作製するには、図１１に図示されるように、上・下部空隙部４０Ｓ１、４０Ｓ２に対応する形状のスペーサ５３ａ、５３ｂを捲回装置５１（図７参照）に植立すればよい。実施形態１の場合と同様、一対の上・下部空隙部４０Ｓ１、４０Ｓ２間に軸芯３０Ａを配置して、軸芯３０Ａおよび一対のスペーサ５３ａ、５３ｂの周囲に、負極電極４２、セパレータ４４、正極電極４１およびセパレータ４３を積層して、捲回する。この後、発電要素４０を、スペーサ５３ａ、５３ｂから引出すことにより、図１０に図示される発電要素４０を得ることができる。   In order to produce the power generating element 40 having the upper gap portion 40S1 and the lower gap portion 40S2, as shown in FIG. 11, spacers 53a and 53b having shapes corresponding to the upper and lower gap portions 40S1 and 40S2 are wound. 51 (see FIG. 7). As in the case of the first embodiment, the shaft core 30A is disposed between the pair of upper and lower gaps 40S1 and 40S2, and the negative electrode 42, the separator 44, and the positive electrode are disposed around the shaft core 30A and the pair of spacers 53a and 53b. The electrode 41 and the separator 43 are stacked and wound. Thereafter, the power generation element 40 shown in FIG. 10 can be obtained by pulling out the power generation element 40 from the spacers 53a and 53b.

なお、実施形態２において、軸芯３０Ａの半楕円部３４ａの高さ方向（Ｙ方向）における先端部が、軸芯部４０Ａの円弧部４０Ｕの高さ方向（Ｙ方向）における端部に実質的に接している構造として例示した。しかし、軸芯３０Ａの半楕円部３４ａは、Ｘ方向における先端部が、軸芯部４０Ａの円弧部４０Ｕの幅方向における端部から離間する構造としてもよい。   In the second embodiment, the tip end portion in the height direction (Y direction) of the semi-elliptical portion 34a of the shaft core 30A is substantially the end portion in the height direction (Y direction) of the arc portion 40U of the shaft core portion 40A. It was illustrated as a structure in contact with However, the semi-elliptical portion 34a of the shaft core 30A may have a structure in which the tip portion in the X direction is separated from the end portion in the width direction of the arc portion 40U of the shaft core portion 40A.

以上説明した通り、本発明の実施形態では、発電要素４０の軸芯部４０Ａに取り付けられる軸芯３０、３０Ａと軸芯部４０Ａとの間に、充放電により発電要素４０が膨張する際、電池缶４を押し広げる作用点となる領域を含む空隙部４０Ｓ、４０Ｓ１、４０Ｓ２を形成した。このため、空隙部４０Ｓ、４０Ｓ１、４０Ｓ２が、発電要素４０が膨張する際の逃げ用の空間となり、角形二次電池１の膨れを緩和することができる。 As described above, in the embodiment of the present invention, when the power generation element 40 expands due to charging / discharging between the shaft cores 30 and 30A attached to the shaft core part 40A of the power generation element 40 and the shaft core part 40A, the battery Cavities 40S, 40S 1 and 40S 2 including regions that serve as action points for spreading the can 4 were formed. For this reason, the gaps 40S, 40S 1 , 40S 2 become a space for escape when the power generation element 40 expands, and the swelling of the rectangular secondary battery 1 can be reduced.

実施形態１および２において、軸芯３０を発電要素４０の軸芯部４０Ａの高さ方向（Ｙ方向）の中心軸と同軸にし、空隙部４０Ｓ、４０Ｓ１、４０Ｓ２を中心軸に対し対称形状とすると、電池缶４の膨れが中心軸に対して対称となるので、角形二次電池１を設置したり、電池モジュールを作製したりする際の取り扱いが容易となる。 In the first and second embodiments, the shaft core 30 is coaxial with the center axis in the height direction (Y direction) of the shaft core portion 40A of the power generation element 40, and the gap portions 40S, 40S 1 , 40S 2 are symmetrical with respect to the center axis. Then, since the swelling of the battery can 4 is symmetric with respect to the central axis, it is easy to handle when installing the square secondary battery 1 or manufacturing the battery module.

上記各実施形態では、軸芯３０、３０Ａの外周に、正極電極４１および負極電極４２を、セパレータ４３、４４を介して１つの捲回体として捲回して作製する。このため、内周捲回体と外周捲回体との間に空隙部を設けて形成する従来の発電要素に比し、空隙部の容積を小さくすることができる。これにより、発電要素４０の充電面積を従来よりも大きくすることができ、充放電の総容量を大きくすることができる。   In each of the above embodiments, the positive electrode 41 and the negative electrode 42 are wound around the outer periphery of the shaft cores 30 and 30 </ b> A as a single wound body via the separators 43 and 44. For this reason, the volume of a space | gap part can be made small compared with the conventional electric power generation element formed by providing a space | gap part between an inner periphery winding body and an outer periphery winding body. Thereby, the charging area of the electric power generation element 40 can be made larger than before, and the total capacity of charging and discharging can be increased.

なお、上記実施形態１では、軸芯３０の高さ方向（Ｙ方向）の両側部に、円弧部３４を設けた構造として例示した。しかし、発電要素４０を作製する際には、軸芯３０の両側部にスペーサ５３を配置して捲回するので、軸芯３０の両側部は、平坦面であっても差し支えない。   In the first embodiment, the structure is illustrated in which the arc portions 34 are provided on both side portions in the height direction (Y direction) of the shaft core 30. However, when the power generating element 40 is manufactured, the spacers 53 are arranged on both sides of the shaft core 30 and wound, so that both sides of the shaft core 30 may be flat surfaces.

上記各実施形態では、電池蓋組立体１０の正極の端子構成部は、外部正極端子６１、正極端子板６３、正極接続端子６２、絶縁部材６４および正極集電板２１を備える構造として例示した。しかし、正極の端子構成部は、上記構造に限られるものではなく、発電要素４０の正極電極４１に接続された正極集電板２１が、電池蓋３とは絶縁された状態で外部接続用端子として電池蓋３の外部に導出される構造であればよい。
このことは、負極の端子構成部においても同様である。 In each of the above embodiments, the positive electrode terminal component of the battery lid assembly 10 is exemplified as a structure including the external positive electrode terminal 61, the positive electrode terminal plate 63, the positive electrode connection terminal 62, the insulating member 64, and the positive electrode current collector plate 21. However, the terminal structure of the positive electrode is not limited to the above structure, and the external connection terminal in a state where the positive current collector 21 connected to the positive electrode 41 of the power generation element 40 is insulated from the battery lid 3. As long as the structure is derived to the outside of the battery lid 3.
The same applies to the terminal component of the negative electrode.

上記実施形態において、電池蓋３と電池缶４により構成される電池容器２の形状は、高さ（Ｙ方向の長さ）よりも幅（Ｘ方向の長さ）が大きい形状とされている。しかし、これとは逆に、高さの方が幅よりも大きいリチウムイオン角形二次電池に適用することが可能である。   In the said embodiment, the shape of the battery container 2 comprised by the battery cover 3 and the battery can 4 is made into the shape whose width (length in the X direction) is larger than height (length in the Y direction). However, on the contrary, the present invention can be applied to a lithium ion prismatic secondary battery whose height is larger than the width.

その他、本発明は、種々、変形して適用することが可能であり、要は、発電要素が、一対の平面部と、平面部の両側部に設けられた円弧部とにより扁平直方体状に形成された軸芯部を有し、軸芯部と軸芯との間には、少なくとも平面部と各円弧部との境界面に跨る領域を有する空隙部が設けられているものであればよい。   In addition, the present invention can be variously modified and applied. In short, the power generation element is formed in a flat rectangular parallelepiped shape by a pair of plane portions and arc portions provided on both sides of the plane portion. What is necessary is just to have the space | interval part which has the area | region straddling the boundary surface of a flat part and each circular arc part between the axial part and an axial center.

１ リチウムイオン角形二次電池
２ 電池容器
３ 電池蓋
４ 電池缶
２１ 正極集電板
２２ 負極集電板
３０、３０Ａ 軸芯
３０Ｚ 境界面
３１ 矩形部
３４ 円弧部
３４ａ 半楕円部
４０ 発電要素
４０Ａ 軸芯部
４０Ｐ、４０Ｑ 平坦部
４０Ｔ、４０Ｕ 円弧部
４０Ｚ 境界面
４０Ｓ、４０Ｓ１、４０Ｓ２ 空隙部
４１ 正極電極
４２ 負極電極
５３、５３ａ、５３ｂ スペーサ
DESCRIPTION OF SYMBOLS 1 Lithium ion square secondary battery 2 Battery container 3 Battery cover 4 Battery can 21 Positive electrode current collecting plate 22 Negative electrode current collecting plate 30, 30A Axis core 30Z Interface 31 Rectangular part 34 Arc part 34a Semi-elliptical part 40 Power generation element 40A Axis core Part 40P, 40Q Flat part 40T, 40U Arc part 40Z Interface 40S, 40S1, 40S2 Air gap part 41 Positive electrode 42 Negative electrode 53, 53a, 53b Spacer

Claims (5)

軸芯の周囲に、正極電極と負極電極とがセパレータを介して捲回され、扁平直方体状に形成された発電要素と、
前記発電要素が収容され、電解液が注入された電池容器と、
前記発電要素の前記正極電極に接続された外部正極端子と、
前記発電要素の前記負極電極に接続された外部負極端子と、を備え、
前記発電要素は、一対の平面部と、前記平面部の両側部に設けられた円弧部とにより扁平直方体状に形成された軸芯部を有し、前記軸芯部と前記軸芯との間には、少なくとも前記平面部と前記各円弧部との境界面に跨る領域を有する空隙部が設けられていることを特徴とするリチウムイオン角形二次電池。 Around the shaft core, a positive electrode and a negative electrode are wound through a separator, and a power generation element formed into a flat rectangular parallelepiped shape,
A battery container in which the power generation element is housed and an electrolyte is injected;
An external positive terminal connected to the positive electrode of the power generation element;
An external negative electrode terminal connected to the negative electrode of the power generation element,
The power generating element has a shaft core portion formed in a flat rectangular parallelepiped shape by a pair of flat surface portions and arc portions provided on both side portions of the flat surface portion, and between the shaft core portion and the shaft core. In the lithium ion prismatic secondary battery, a void portion having a region straddling at least a boundary surface between the flat portion and each arc portion is provided. 請求項１に記載のリチウムイオン角形二次電池において、前記発電要素の前記軸芯部は、前記発電要素の捲回方向である幅方向の長さが、前記軸芯の幅方向における長さよりも大きく形成され、前記空隙部は、前記軸芯部における前記各円弧部の幅方向の端部と前記軸芯の両側部の各先端部との間に設けられていることを特徴とするリチウムイオン角形二次電池。   2. The lithium ion prismatic secondary battery according to claim 1, wherein the shaft core portion of the power generation element has a length in a width direction that is a winding direction of the power generation element is larger than a length in a width direction of the shaft core. Lithium ions, characterized in that the lithium ion is formed large, and the gap is provided between an end in the width direction of each arc in the shaft core and each tip of both sides of the shaft. Square secondary battery. 請求項２に記載のリチウムイオン角形二次電池において、前記軸芯の捲回方向における両側部は、それぞれ、円弧状に形成され、かつ、前記各円弧状の側部の幅方向における先端部は、前記平面部と前記各円弧部との境界面よりも内方に位置していることを特徴とするリチウムイオン角形二次電池。   3. The lithium ion prismatic secondary battery according to claim 2, wherein both side portions in the winding direction of the shaft core are each formed in an arc shape, and tip portions in the width direction of the respective arc-shaped side portions are The lithium ion prismatic secondary battery is located inward of a boundary surface between the flat portion and each arc portion. 請求項１に記載のリチウムイオン角形二次電池において、前記軸芯の捲回方向における両側部は、それぞれ、先細に形成され、前記先細の先端部は、前記平面部と前記各円弧部との境界面の外側に張り出していることを特徴とするリチウムイオン角形二次電池。   2. The lithium ion prismatic secondary battery according to claim 1, wherein both side portions in the winding direction of the shaft core are each formed in a tapered shape, and the tapered tip portion is formed between the planar portion and each arc portion. A lithium ion prismatic secondary battery characterized by projecting to the outside of a boundary surface. 請求項４に記載のリチウムイオン角形二次電池において、前記軸芯の捲回方向における両側部の各先端部は、前記軸芯部の捲回方向における先端部に実質的に接していることを特徴とするリチウムイオン角形二次電池。

5. The lithium ion prismatic secondary battery according to claim 4, wherein each front end of each side portion in the winding direction of the shaft core is substantially in contact with a front end portion in the winding direction of the shaft core portion. A featured lithium ion prismatic secondary battery.

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Publication number Priority date Publication date Assignee Title
US10991969B2 (en) 2014-08-18 2021-04-27 Gs Yuasa International Ltd. Energy storage device

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JP2004319449A (en) * 2003-04-02 2004-11-11 Matsushita Electric Ind Co Ltd Energy device and its manufacturing method
WO2012004886A1 (en) * 2010-07-09 2012-01-12 日立ビークルエナジー株式会社 Secondary battery and method for manufacturing flat wound electrode group

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Publication number Priority date Publication date Assignee Title
JP2004319449A (en) * 2003-04-02 2004-11-11 Matsushita Electric Ind Co Ltd Energy device and its manufacturing method
WO2012004886A1 (en) * 2010-07-09 2012-01-12 日立ビークルエナジー株式会社 Secondary battery and method for manufacturing flat wound electrode group

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10991969B2 (en) 2014-08-18 2021-04-27 Gs Yuasa International Ltd. Energy storage device

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