JP6859752B2 - Power storage device - Google Patents

Power storage device Download PDF

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JP6859752B2
JP6859752B2 JP2017037553A JP2017037553A JP6859752B2 JP 6859752 B2 JP6859752 B2 JP 6859752B2 JP 2017037553 A JP2017037553 A JP 2017037553A JP 2017037553 A JP2017037553 A JP 2017037553A JP 6859752 B2 JP6859752 B2 JP 6859752B2
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negative electrode
positive electrode
electrode
separator
insulating sheet
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JP2018142512A (en
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厚志 南形
厚志 南形
雅人 小笠原
雅人 小笠原
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Toyota Industries Corp
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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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  • Secondary Cells (AREA)
  • Connection Of Batteries Or Terminals (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
  • Cell Separators (AREA)

Description

本発明は、蓄電装置に関する。 The present invention relates to a power storage device.

二次電池や、キャパシタなどの蓄電装置は、金属製のケースと、ケースに収容された電極組立体とを備える。電極組立体は、正極電極と、負極電極と、正極電極と負極電極とを絶縁するセパレータとを備える。蓄電装置に加わる振動や衝撃などで電極組立体がケースに接すると短絡の原因となる。特許文献１に記載の蓄電装置は、ケースと電極組立体との間に介在している絶縁シートを備える。絶縁シートによってケースと電極組立体とを電気的に絶縁することで、ケースと電極組立体との短絡を抑制している。 A power storage device such as a secondary battery or a capacitor includes a metal case and an electrode assembly housed in the case. The electrode assembly includes a positive electrode, a negative electrode, and a separator that insulates the positive electrode and the negative electrode. If the electrode assembly comes into contact with the case due to vibration or impact applied to the power storage device, it may cause a short circuit. The power storage device described in Patent Document 1 includes an insulating sheet interposed between the case and the electrode assembly. By electrically insulating the case and the electrode assembly with an insulating sheet, a short circuit between the case and the electrode assembly is suppressed.

特開２０１１−１９８６６３号公報Japanese Unexamined Patent Publication No. 2011-198663

ところで、複数の正極電極と複数の負極電極とを交互に積層した電極組立体を用いる場合、各電極の角と、ケースの底壁及び側壁とで絶縁シートが挟まれる。この状態で蓄電装置に振動や衝撃が加わると、各電極の角から絶縁シートに加わる荷重により絶縁シートが損傷し、短絡の原因となる。 By the way, when an electrode assembly in which a plurality of positive electrode electrodes and a plurality of negative electrode electrodes are alternately laminated is used, an insulating sheet is sandwiched between the corners of each electrode and the bottom wall and side wall of the case. If vibration or impact is applied to the power storage device in this state, the insulating sheet is damaged by the load applied to the insulating sheet from the corners of each electrode, which causes a short circuit.

本発明の目的は、ケースと電極組立体との短絡を抑制できる蓄電装置を提供することにある。 An object of the present invention is to provide a power storage device capable of suppressing a short circuit between a case and an electrode assembly.

上記課題を解決する蓄電装置は、複数の正極電極と複数の負極電極とを前記正極電極と前記負極電極との間に配置したセパレータで絶縁した状態で交互に積層した電極組立体と、前記電極組立体が収容されたケースと、前記電極組立体と前記ケースとの間に介在し、前記電極組立体と前記ケースとを絶縁している絶縁シートと、を備え、前記ケースは、底壁と、側壁と、前記底壁と前記側壁とを繋ぐケース隅部と、を備え、前記負極電極は、負極金属箔に負極活物質層を設けた負極本体と、前記負極金属箔からなり、前記負極本体から延びる負極タブと、を備え、前記負極本体は、前記絶縁シートを介して前記底壁に向かい合う第１負極面と、前記絶縁シートを介して前記側壁に向かい合う第２負極面と、前記第１負極面と前記第２負極面との間に位置して前記第１負極面と前記第２負極面とを接続し、前記絶縁シートを介して前記ケース隅部に向かい合う負極面取部と、を備え、前記セパレータは、前記絶縁シートを介して前記底壁に向かい合う第１セパレータ面と、前記絶縁シートを介して前記側壁に向かい合い、前記第１セパレータ面に接続する第２セパレータ面と、を備え、前記正極電極と前記負極電極との積層方向から見て、前記負極本体の外形は前記セパレータの外形内に収まり、前記第１セパレータ面と前記第２セパレータ面とが接続する角は、前記積層方向から見て、前記負極面取部と前記絶縁シートとの間に位置している。 The power storage device that solves the above problems includes an electrode assembly in which a plurality of positive electrode electrodes and a plurality of negative electrode electrodes are alternately laminated in a state of being insulated by a separator arranged between the positive electrode electrode and the negative electrode electrode, and the electrode. A case containing the assembly and an insulating sheet interposed between the electrode assembly and the case and insulating the electrode assembly and the case are provided, and the case is provided with a bottom wall. The negative electrode is composed of a negative electrode body provided with a negative electrode active material layer on a negative electrode metal foil and the negative electrode metal foil, and comprises a side wall and a case corner portion connecting the bottom wall and the side wall. The negative electrode main body includes a negative electrode tab extending from the main body, and the negative electrode main body has a first negative electrode surface facing the bottom wall via the insulating sheet, a second negative electrode surface facing the side wall via the insulating sheet, and the first negative electrode surface. A negative electrode chamfered portion that is located between the 1 negative electrode surface and the 2nd negative electrode surface, connects the 1st negative electrode surface and the 2nd negative electrode surface, and faces the corner corner of the case via the insulating sheet. The separator comprises a first separator surface facing the bottom wall via the insulating sheet, and a second separator surface facing the side wall via the insulating sheet and connecting to the first separator surface. When viewed from the stacking direction of the positive electrode and the negative electrode, the outer shape of the negative electrode body fits within the outer shape of the separator, and the angle at which the first separator surface and the second separator surface are connected is described above. It is located between the negative electrode chamfered portion and the insulating sheet when viewed from the stacking direction.

これによれば、負極面取部を設けることで、第１負極面と第２負極面とで、直角や鋭角が形成されないようにしている。更に、正極電極と負極電極との積層方向から見て、セパレータの角を、負極面取部と絶縁シートとの間に位置させることで、セパレータの一部が負極面取部と絶縁シートとの間に介在する。負極面取部が絶縁シートに接触しようとすると、セパレータを介して絶縁シートに接触することになる。これにより、ケースと電極組立体との短絡を抑制することができる。 According to this, by providing the negative electrode chamfered portion, a right angle or an acute angle is not formed between the first negative electrode surface and the second negative electrode surface. Further, by locating the corners of the separator between the negative electrode chamfered portion and the insulating sheet when viewed from the stacking direction of the positive electrode and the negative electrode, a part of the separator can be formed between the negative electrode chamfered portion and the insulating sheet. Intervene in between. When the negative electrode chamfered portion tries to come into contact with the insulating sheet, it comes into contact with the insulating sheet via the separator. As a result, a short circuit between the case and the electrode assembly can be suppressed.

上記蓄電装置について、前記正極電極は、正極金属箔に正極活物質層を設けた正極本体と、前記正極金属箔からなり、前記正極本体から延びる正極タブと、を備え、前記正極本体は、前記絶縁シートを介して前記底壁に向かい合う第１正極面と、前記絶縁シートを介して前記側壁に向かい合う第２正極面と、前記第１正極面と前記第２正極面の間に位置して前記第１正極面と前記第２正極面とを接続し、前記絶縁シートを介して前記ケース隅部に向かい合う正極面取部と、を備えていてもよい。 Regarding the power storage device, the positive electrode includes a positive electrode body provided with a positive electrode active material layer on a positive electrode metal foil, and a positive electrode tab composed of the positive electrode metal foil and extending from the positive electrode body. The first positive electrode surface facing the bottom wall via the insulating sheet, the second positive electrode surface facing the side wall via the insulating sheet, and the position between the first positive electrode surface and the second positive electrode surface. A positive electrode chamfering portion that connects the first positive electrode surface and the second positive electrode surface and faces the corner portion of the case via the insulating sheet may be provided.

これによれば、正極電極に正極面取部を設けることで、正極電極と絶縁シートの接触によって絶縁シートが損傷することを抑制することができる。
上記蓄電装置について、前記ケース隅部の内面は、アール状であり、前記負極面取部は、前記ケース隅図の内面に向けて膨らむアール状であり、前記ケース隅部の前記内面の半径は、前記負極面取部の半径に前記絶縁シートの厚みを加えた寸法よりも小さくてもよい。 According to this, by providing the positive electrode with the positive electrode chamfered portion, it is possible to prevent the insulating sheet from being damaged by the contact between the positive electrode and the insulating sheet.
Regarding the power storage device, the inner surface of the corner of the case has a rounded shape, the chamfered negative electrode has a rounded shape that bulges toward the inner surface of the corner view of the case, and the radius of the inner surface of the corner of the case is , The dimension may be smaller than the radius of the negative electrode chamfered portion plus the thickness of the insulating sheet.

これによれば、負極面取部と、絶縁シートとの間の隙間が維持されやすい。負極面取部が絶縁シートに接触しにくく、絶縁シートの損傷が更に抑制される。 According to this, the gap between the negative electrode chamfered portion and the insulating sheet is easily maintained. The negative electrode chamfered portion is less likely to come into contact with the insulating sheet, and damage to the insulating sheet is further suppressed.

本発明によれば、ケースと電極組立体との短絡を抑制できる。 According to the present invention, a short circuit between the case and the electrode assembly can be suppressed.

二次電池の分解斜視図。An exploded perspective view of the secondary battery. 二次電池の一部を拡大して示す断面図。FIG. 5 is an enlarged sectional view showing a part of a secondary battery. 電極組立体の分解斜視図。An exploded perspective view of the electrode assembly. 正極電極、負極電極、及び、セパレータの正面図。Front view of positive electrode, negative electrode, and separator. 電極組立体の一部を拡大して示す斜視図。The perspective view which shows a part of the electrode assembly enlarged. 電極組立体を示す図５の６−６線断面図。FIG. 5 is a sectional view taken along line 6-6 of FIG. 5 showing an electrode assembly. 二次電池を示す図２の７−７線断面図。FIG. 2 is a sectional view taken along line 7-7 of FIG. 2 showing a secondary battery. 面取部の変形例を示す図。The figure which shows the deformation example of the chamfer part.

以下、蓄電装置の一実施形態について説明する。
図１に示すように、蓄電装置としての二次電池１０は、箱状のケース２０と、ケース２０に収容された電極組立体４０とを備える。本実施形態の二次電池１０は、角型電池であり、リチウムイオン電池である。ケース２０は、本体２２と、蓋部材２１とを備える。 Hereinafter, an embodiment of the power storage device will be described.
As shown in FIG. 1, the secondary battery 10 as a power storage device includes a box-shaped case 20 and an electrode assembly 40 housed in the case 20. The secondary battery 10 of the present embodiment is a square battery and is a lithium ion battery. The case 20 includes a main body 22 and a lid member 21.

図１及び図２に示すように、本体２２は、矩形状の底壁２３と、四角筒状の側壁２５と、底壁２３と側壁２５とを繋ぐケース隅部２４と、を備える。側壁２５は、ケース隅部２４を介して、底壁２３から立設している。ケース隅部２４は、底壁２３から側壁２５に向けて、ケース２０の外側に凸となるアール形状（円弧形状）である。ケース２０は、深絞り加工や、インパクトプレス加工などの塑性加工によって金属板を塑性変形させることで製造されている。ケース隅部２４は、塑性加工に際して生じるものである。 As shown in FIGS. 1 and 2, the main body 22 includes a rectangular bottom wall 23, a square tubular side wall 25, and a case corner 24 connecting the bottom wall 23 and the side wall 25. The side wall 25 is erected from the bottom wall 23 via the case corner 24. The case corner portion 24 has a rounded shape (arc shape) that is convex outward from the case 20 from the bottom wall 23 toward the side wall 25. The case 20 is manufactured by plastically deforming a metal plate by plastic working such as deep drawing or impact press working. The case corner 24 is generated during plastic working.

側壁２５は、互いに向かい合う一対の第１側部２６と、互いに向かい合う一対の第２側部２７と、を備える。第１側部２６は、底壁２３の短辺からケース隅部２４を介して立設している。第２側部２７は、底壁２３の長辺からケース隅部２４を介して立設している。 The side wall 25 includes a pair of first side portions 26 facing each other and a pair of second side portions 27 facing each other. The first side portion 26 is erected from the short side of the bottom wall 23 via the case corner portion 24. The second side portion 27 is erected from the long side of the bottom wall 23 via the case corner portion 24.

電極組立体４０は、本体２２に収容されている。蓋部材２１は、本体２２に電極組立体４０を収容した後に本体２２に溶接されることで、側壁２５によって囲まれた開口部２８を閉塞している。 The electrode assembly 40 is housed in the main body 22. The lid member 21 closes the opening 28 surrounded by the side wall 25 by accommodating the electrode assembly 40 in the main body 22 and then welding it to the main body 22.

二次電池１０は、ケース２０に収容された電極組立体４０と、ケース２０とを電気的に絶縁している絶縁シート３０を備える。絶縁シート３０は、本体２２の内面と電極組立体４０との間に介在している。絶縁シート３０は、例えば、ポロプロピレン製である。絶縁シート３０の厚みＴは、例えば、１５０μｍ以上である。絶縁シート３０は、本体２２の内面に沿っている。 The secondary battery 10 includes an electrode assembly 40 housed in the case 20 and an insulating sheet 30 that electrically insulates the case 20. The insulating sheet 30 is interposed between the inner surface of the main body 22 and the electrode assembly 40. The insulating sheet 30 is made of, for example, polypropylene. The thickness T of the insulating sheet 30 is, for example, 150 μm or more. The insulating sheet 30 is along the inner surface of the main body 22.

図３に示すように、電極組立体４０は、複数の負極電極４１と、複数の正極電極５１と、複数の袋状セパレータ８１と、を備える。正極電極５１は、袋状セパレータ８１に収納されている。 As shown in FIG. 3, the electrode assembly 40 includes a plurality of negative electrode electrodes 41, a plurality of positive electrode electrodes 51, and a plurality of bag-shaped separators 81. The positive electrode 51 is housed in the bag-shaped separator 81.

負極電極４１は、負極本体４２と、負極タブ４３とを備える。負極本体４２は、負極金属箔（本実施形態では銅箔）４４と、負極金属箔４４の両面に設けられた負極活物質層４５とを備える。負極活物質層４５は、負極用の活物質、バインダ、及び導電助剤などを含有している。負極タブ４３は、負極金属箔４４の一部を負極本体４２から突出するように延ばした部分である。 The negative electrode electrode 41 includes a negative electrode body 42 and a negative electrode tab 43. The negative electrode body 42 includes a negative electrode metal foil (copper foil in this embodiment) 44 and negative electrode active material layers 45 provided on both sides of the negative electrode metal foil 44. The negative electrode active material layer 45 contains an active material for the negative electrode, a binder, a conductive auxiliary agent, and the like. The negative electrode tab 43 is a portion in which a part of the negative electrode metal foil 44 is extended so as to protrude from the negative electrode main body 42.

正極電極５１は、正極本体５２と、正極タブ５３とを備える。正極本体５２は、正極金属箔（本実施形態ではアルミニウム箔）５４と、正極金属箔５４の両面に設けられた正極活物質層５５とを備える。正極活物質層５５は、正極用の活物質、バインダ、及び導電助剤などを含有している。正極タブ５３は、正極金属箔５４の一部を正極本体５２から突出するように延ばした部分である。 The positive electrode electrode 51 includes a positive electrode main body 52 and a positive electrode tab 53. The positive electrode body 52 includes a positive electrode metal foil (aluminum foil in this embodiment) 54 and a positive electrode active material layer 55 provided on both sides of the positive electrode metal foil 54. The positive electrode active material layer 55 contains an active material for the positive electrode, a binder, a conductive auxiliary agent, and the like. The positive electrode tab 53 is a portion in which a part of the positive electrode metal foil 54 is extended so as to protrude from the positive electrode main body 52.

リチウムイオン電池においては、負極電極４１でのリチウムの析出を抑制するために負極電極４１の容量を正極電極５１の容量に比べて多くしている。したがって、負極本体４２を正面視したときの面積は正極本体５２を正面視したときの面積よりも大きく、厚みを除く負極本体４２の外形寸法は正極本体５２の外形寸法よりも大きい。まず、負極本体４２について説明する。 In the lithium ion battery, the capacity of the negative electrode 41 is made larger than the capacity of the positive electrode 51 in order to suppress the precipitation of lithium on the negative electrode 41. Therefore, the area when the negative electrode body 42 is viewed from the front is larger than the area when the positive electrode body 52 is viewed from the front, and the external dimensions of the negative electrode body 42 excluding the thickness are larger than the external dimensions of the positive electrode body 52. First, the negative electrode body 42 will be described.

図３及び図４に示すように、負極本体４２は、正面視したときに短辺と長辺とを備える略矩形状である。負極本体４２は、互いに平行に延びる面である負極上端面６２及び負極下端面６３を周縁に備える。負極上端面６２及び負極下端面６３は、矩形状である。負極上端面６２及び負極下端面６３は、負極本体４２を正面視したときに長辺を構成する面である。負極本体４２は、互いに平行に延びる面である一対の負極側端面６４，６５を周縁に備える。負極側端面６４，６５は、負極本体４２を正面視したときに短辺を構成する面である。負極タブ４３は、負極上端面６２に一体に設けられている。 As shown in FIGS. 3 and 4, the negative electrode main body 42 has a substantially rectangular shape having a short side and a long side when viewed from the front. The negative electrode body 42 includes a negative electrode upper end surface 62 and a negative electrode lower end surface 63, which are surfaces extending in parallel with each other, on the peripheral edge. The negative electrode upper end surface 62 and the negative electrode lower end surface 63 have a rectangular shape. The negative electrode upper end surface 62 and the negative electrode lower end surface 63 are surfaces forming long sides when the negative electrode body 42 is viewed from the front. The negative electrode body 42 includes a pair of negative electrode side end faces 64, 65, which are surfaces extending in parallel with each other, on the peripheral edge. The negative electrode side end faces 64 and 65 are surfaces forming a short side when the negative electrode body 42 is viewed from the front. The negative electrode tab 43 is integrally provided on the upper end surface 62 of the negative electrode.

負極本体４２は、負極下端面６３と各負極側端面６４，６５との間に位置して負極下端面６３と各負極側端面６４，６５とを接続している負極面取部６６を備える。負極面取部６６は、２つ設けられている。負極面取部６６は、負極下端面６３と各負極側端面６４，６５に対して斜めに交わる面である。負極上端面６２、負極下端面６３、及び、負極側端面６４，６５によって負極本体４２の周縁は構成されている。本実施形態の負極面取部６６は、Ｃ面状である。 The negative electrode body 42 includes a negative electrode chamfering portion 66 located between the negative electrode lower end surface 63 and the negative electrode side end surfaces 64, 65 and connecting the negative electrode lower end surface 63 and the negative electrode side end surfaces 64, 65. Two negative electrode chamfered portions 66 are provided. The negative electrode chamfered portion 66 is a surface that diagonally intersects the negative electrode lower end surface 63 with respect to the negative electrode side end surfaces 64 and 65. The peripheral edge of the negative electrode body 42 is composed of the negative electrode upper end surface 62, the negative electrode lower end surface 63, and the negative electrode side end surfaces 64 and 65. The negative electrode chamfered portion 66 of this embodiment has a C-plane shape.

「負極面取部」とは、負極面取部６６がなければ直角、あるいは、鋭角に交わる面同士を繋ぐことで、電極組立体４０における底壁２３及び側壁２５と対向する部位に直角、あるいは、鋭角が生じないようにしている面である。「負極面取部」とは、実際に面取りを行うことで生じた面のみを示すものではなく、直角、あるいは、鋭角を底壁２３と対向する部位に備える負極本体４２を面取りしたと想定した面も含む。例えば、切断加工によって、負極上端面６２、負極下端面６３、各負極側端面６４，６５、及び、負極面取部６６が同時に製造され、実際に面取りが行われていない負極本体４２であっても負極下端面６３と負極側端面６４，６５に対して斜めに交わる面が負極面取部６６に該当する。 The "negative electrode chamfered portion" is a right angle if there is no negative electrode chamfered portion 66, or is perpendicular to a portion of the electrode assembly 40 facing the bottom wall 23 and the side wall 25 by connecting surfaces that intersect at an acute angle. , It is a surface that prevents acute angles from occurring. The "negative electrode chamfered portion" does not indicate only the surface generated by the actual chamfering, but it is assumed that the negative electrode body 42 having a right angle or an acute angle facing the bottom wall 23 is chamfered. Also includes faces. For example, the negative electrode body 42 in which the negative electrode upper end surface 62, the negative electrode lower end surface 63, the negative electrode side end surfaces 64 and 65, and the negative electrode chamfered portion 66 are simultaneously manufactured by cutting, and the negative electrode body 42 is not actually chamfered. The surface that diagonally intersects the negative electrode lower end surface 63 and the negative electrode side end surfaces 64 and 65 corresponds to the negative electrode chamfered portion 66.

正極本体５２は、正面視したときに短辺と長辺とを備える略矩形状である。正極本体５２は、互いに平行に延びる面である正極上端面７２及び正極下端面７３を周縁に備える。正極上端面７２及び正極下端面７３は、矩形状である。正極上端面７２及び正極下端面７３は、正極本体５２を正面視したときに長辺を構成する面である。正極本体５２は、互いに平行に延びる面である一対の正極側端面７４，７５を周縁に備える。正極側端面７４，７５は、正極本体５２を正面視したときに短辺を構成する面である。正極タブ５３は、正極上端面７２に一体に設けられている。 The positive electrode body 52 has a substantially rectangular shape having a short side and a long side when viewed from the front. The positive electrode body 52 includes a positive electrode upper end surface 72 and a positive electrode lower end surface 73, which are surfaces extending in parallel with each other, on the peripheral edge. The positive electrode upper end surface 72 and the positive electrode lower end surface 73 have a rectangular shape. The positive electrode upper end surface 72 and the positive electrode lower end surface 73 are surfaces forming long sides when the positive electrode body 52 is viewed from the front. The positive electrode body 52 is provided with a pair of positive electrode side end faces 74 and 75, which are surfaces extending in parallel with each other, on the peripheral edge. The positive electrode side end faces 74 and 75 are surfaces forming a short side when the positive electrode body 52 is viewed from the front. The positive electrode tab 53 is integrally provided on the upper end surface 72 of the positive electrode.

正極本体５２は、正極下端面７３と各正極側端面７４，７５との間に位置して正極下端面７３と各正極側端面７４，７５とを接続している正極面取部７６を備える。正極面取部７６は、２つ設けられている。正極面取部７６は、正極下端面７３と各正極側端面７４，７５に対して斜めに交わる面である。正極上端面７２、正極下端面７３、及び、正極面取部７６によって正極本体５２の周縁は構成されている。本実施形態の正極面取部７６は、Ｃ面状である。 The positive electrode body 52 includes a positive electrode chamfered portion 76 that is located between the lower end surface 73 of the positive electrode and the end faces 74 and 75 on the positive electrode side and connects the lower end surface 73 of the positive electrode and the end faces 74 and 75 on the positive electrode side. Two positive electrode chamfered portions 76 are provided. The positive electrode chamfered portion 76 is a surface that diagonally intersects the lower end surface 73 of the positive electrode with respect to the end surfaces 74 and 75 on the positive electrode side. The peripheral edge of the positive electrode body 52 is composed of the positive electrode upper end surface 72, the positive electrode lower end surface 73, and the positive electrode chamfered portion 76. The positive electrode chamfered portion 76 of this embodiment has a C-plane shape.

「正極面取部」とは、正極面取部７６がなければ直角、あるいは、鋭角に交わる面同士を繋ぐことで、電極組立体４０における底壁２３及び側壁２５と対向する部位に直角、あるいは、鋭角が生じないようにしている面である。「正極面取部」とは、実際に面取りを行うことで生じた面のみを示すものではなく、直角、あるいは、鋭角を底壁２３と対向する部位に備える正極本体５２を面取りしたと想定した面も含む。例えば、切断加工によって、正極上端面７２、正極下端面７３、各正極側端面７４，７５、及び、正極面取部７６が同時に製造され、実際に面取りが行われていない正極本体５２であっても正極下端面７３と正極側端面７４，７５に対して斜めに交わる面が正極面取部７６に該当する。 The "positive electrode chamfered portion" is a right angle if there is no positive electrode chamfered portion 76, or is perpendicular to a portion of the electrode assembly 40 facing the bottom wall 23 and the side wall 25 by connecting surfaces that intersect at an acute angle. , It is a surface that prevents acute angles from occurring. The "positive electrode chamfered portion" does not indicate only the surface generated by actually chamfering, but it is assumed that the positive electrode main body 52 having a right angle or an acute angle facing the bottom wall 23 is chamfered. Also includes faces. For example, the positive electrode main body 52 in which the positive electrode upper end surface 72, the positive electrode lower end surface 73, the positive electrode side end surfaces 74 and 75, and the positive electrode chamfered portion 76 are simultaneously manufactured by cutting, and are not actually chamfered. The surface that diagonally intersects the positive electrode lower end surface 73 and the positive electrode side end surfaces 74 and 75 corresponds to the positive electrode chamfered portion 76.

図４に示すように、正極上端面７２の長手方向（各正極側端面７４，７５が向かい合う方向）の寸法Ｌ２１は、負極上端面６２の長手方向（各負極側端面６４，６５の向かい合う方向）の寸法Ｌ１１に比べて短い。正極下端面７３の長手方向（各正極側端面７４，７５が向かい合う方向）の寸法Ｌ２２は、負極下端面６３の長手方向（各負極側端面６４，６５が向かい合う方向）の寸法Ｌ１２に比べて短い。各正極側端面７４，７５の長手方向（正極上端面７２と正極下端面７３とが向かい合う方向）の寸法Ｌ２３，Ｌ２４は、各負極側端面６４，６５の長手方向（負極上端面６２と負極下端面６３とが向かい合う方向）の寸法Ｌ１３，Ｌ１４に比べて短い。 As shown in FIG. 4, the dimension L21 in the longitudinal direction of the positive electrode upper end surface 72 (the direction in which the positive electrode side end faces 74 and 75 face each other) is the longitudinal direction of the negative electrode upper end surface 62 (the directions in which the negative electrode side end faces 64 and 65 face each other). It is shorter than the dimension L11 of. The dimension L22 in the longitudinal direction of the positive electrode lower end surface 73 (the direction in which the positive electrode side end faces 74 and 75 face each other) is shorter than the dimension L12 in the longitudinal direction of the negative electrode lower end surface 63 (the direction in which the negative electrode side end faces 64 and 65 face each other). .. The dimensions L23 and L24 in the longitudinal direction of the positive electrode side end faces 74 and 75 (the direction in which the positive electrode upper end surface 72 and the positive electrode lower end surface 73 face each other) are the longitudinal directions of the negative electrode side end faces 64 and 65 (negative electrode upper end surface 62 and below the negative electrode). It is shorter than the dimensions L13 and L14 (in the direction in which the end face 63 faces each other).

図３に示すように、袋状セパレータ８１は、セパレータとしての２つのセパレータ片８２を備える。各セパレータ片８２は同一形状である。セパレータ片８２は、矩形状である。２つのセパレータ片８２の周縁は、溶着などで接合されている。これにより、２つのセパレータ片８２における接合された部分の内側に収納スペースが区画されている。袋状セパレータ８１には、正極電極５１が収納されている。正極タブ５３の一部は、袋状セパレータ８１から突出している。 As shown in FIG. 3, the bag-shaped separator 81 includes two separator pieces 82 as separators. Each separator piece 82 has the same shape. The separator piece 82 has a rectangular shape. The peripheral edges of the two separator pieces 82 are joined by welding or the like. As a result, the storage space is partitioned inside the joined portion of the two separator pieces 82. The positive electrode 51 is housed in the bag-shaped separator 81. A part of the positive electrode tab 53 protrudes from the bag-shaped separator 81.

図４に示すように、袋状セパレータ８１は、互いに平行であるセパレータ上端面８３及びセパレータ下端面８４と、互いに平行である一対のセパレータ側端面８５とを備える。セパレータ上端面８３の長手方向（セパレータ側端面８５が向かい合う方向）の寸法Ｌ３１とセパレータ下端面８４の長手方向（セパレータ側端面８５が向かい合う方向）の寸法Ｌ３２とは同一である。各セパレータ側端面８５の長手方向（セパレータ上端面８３とセパレータ下端面８４とが向かう合う方向）の寸法Ｌ３３は同一である。セパレータ上端面８３とセパレータ側端面８５とが接続する角Ｃ１、及び、セパレータ下端面８４とセパレータ側端面８５とが接続する角Ｃ２は直角である。 As shown in FIG. 4, the bag-shaped separator 81 includes a separator upper end surface 83 and a separator lower end surface 84 that are parallel to each other, and a pair of separator side end surfaces 85 that are parallel to each other. The dimension L31 in the longitudinal direction of the separator upper end surface 83 (the direction in which the separator side end faces 85 face each other) and the dimension L32 in the longitudinal direction of the separator lower end surface 84 (the direction in which the separator side end faces 85 face each other) are the same. The dimensions L33 of each separator side end surface 85 in the longitudinal direction (direction in which the separator upper end surface 83 and the separator lower end surface 84 face each other) are the same. The angle C1 connecting the upper end surface 83 of the separator and the end surface 85 on the separator side and the angle C2 connecting the lower end surface 84 of the separator and the end surface 85 on the separator side are right angles.

なお、袋状セパレータ８１は、同一形状のセパレータ片８２を溶着することで構成されているため、セパレータ上端面８３、セパレータ下端面８４、及び、各セパレータ側端面８５は、各セパレータ片８２の端面で連続することで構成されているものである。即ち、各セパレータ片８２のそれぞれが、セパレータ上端面、セパレータ下端面、及び、各セパレータ側端面を備え、これらが連なることで袋状セパレータ８１のセパレータ上端面８３、セパレータ下端面８４、及び、各セパレータ側端面８５は、各セパレータ片８２を構成していると捉えることもできる。 Since the bag-shaped separator 81 is formed by welding separator pieces 82 having the same shape, the upper end surface 83 of the separator, the lower end surface 84 of the separator, and the end surface 85 on each separator side are the end surfaces of the separator pieces 82. It is composed of being continuous with. That is, each of the separator pieces 82 has a separator upper end surface, a separator lower end surface, and each separator side end surface, and by connecting these, the separator upper end surface 83, the separator lower end surface 84, and each of the bag-shaped separator 81. The separator side end face 85 can also be regarded as forming each separator piece 82.

厚みを除く袋状セパレータ８１の外形寸法は、負極面取部６６が設けられていないと仮定した場合の負極電極４１の外形寸法以上であり、本実施形態では同一である。セパレータ上端面８３の長手方向の寸法Ｌ３１、及び、セパレータ下端面８４の長手方向の寸法Ｌ３２は、負極上端面６２の長手方向の寸法Ｌ１１と同一である。セパレータ側端面８５の長手方向の寸法Ｌ３３は、負極上端面６２と負極下端面６３との間隔Ｌ１５と同一である。 The external dimensions of the bag-shaped separator 81 excluding the thickness are equal to or larger than the external dimensions of the negative electrode electrode 41 when it is assumed that the negative electrode chamfered portion 66 is not provided, and are the same in the present embodiment. The longitudinal dimension L31 of the separator upper end surface 83 and the longitudinal dimension L32 of the separator lower end surface 84 are the same as the longitudinal dimension L11 of the negative electrode upper end surface 62. The dimension L33 in the longitudinal direction of the separator side end surface 85 is the same as the distance L15 between the negative electrode upper end surface 62 and the negative electrode lower end surface 63.

図３に示すように、正極電極５１は、セパレータ上端面８３と正極上端面７２とが同一方向を向き、セパレータ下端面８４と正極下端面７３とが同一方向を向く状態で袋状セパレータ８１に収納されている。 As shown in FIG. 3, the positive electrode electrode 51 is formed on the bag-shaped separator 81 in a state where the upper end surface 83 of the separator and the upper end surface 72 of the positive electrode face the same direction, and the lower end surface 84 of the separator and the lower end surface 73 of the positive electrode face the same direction. It is stored.

図５及び図６に示すように、電極組立体４０は、負極電極４１と、袋状セパレータ８１に収納された正極電極５１とを交互に積層することで構成されている。以下の説明において、「積層方向」とは、負極電極４１と正極電極５１の積層方向を示すものとする。 As shown in FIGS. 5 and 6, the electrode assembly 40 is configured by alternately stacking the negative electrode 41 and the positive electrode 51 housed in the bag-shaped separator 81. In the following description, the "stacking direction" means the stacking direction of the negative electrode 41 and the positive electrode 51.

袋状セパレータ８１によって負極電極４１と正極電極５１とは絶縁されている。負極下端面６３、正極下端面７３、及び、セパレータ下端面８４は同一方向を向いている。負極上端面６２、正極上端面７２、及び、セパレータ上端面８３は同一方向を向いている。正極電極５１と負極電極４１の積層方向から見て、袋状セパレータ８１の角Ｃ２は、負極面取部６６よりも外方に突出している。 The negative electrode 41 and the positive electrode 51 are insulated from each other by the bag-shaped separator 81. The lower end surface 63 of the negative electrode, the lower end surface 73 of the positive electrode, and the lower end surface 84 of the separator face in the same direction. The negative electrode upper end surface 62, the positive electrode upper end surface 72, and the separator upper end surface 83 face in the same direction. When viewed from the stacking direction of the positive electrode 51 and the negative electrode 41, the corner C2 of the bag-shaped separator 81 projects outward from the negative electrode chamfered portion 66.

負極本体４２の外形寸法と袋状セパレータ８１の外形寸法は、厚みを除いて同一であるため、積層方向から見て負極本体４２と、袋状セパレータ８１とは全体が対向する。積層方向から見て、負極本体４２の外形は袋状セパレータ８１の外形内に収まっているといえる。換言すれば、積層方向から見て、負極本体４２は、袋状セパレータ８１の領域内に投影される。 Since the external dimensions of the negative electrode body 42 and the external dimensions of the bag-shaped separator 81 are the same except for the thickness, the negative electrode body 42 and the bag-shaped separator 81 face each other as a whole when viewed from the stacking direction. It can be said that the outer shape of the negative electrode body 42 is contained within the outer shape of the bag-shaped separator 81 when viewed from the stacking direction. In other words, the negative electrode body 42 is projected into the region of the bag-shaped separator 81 when viewed from the stacking direction.

電極組立体４０の外面は、負極電極４１、及び、袋状セパレータ８１が連なることで構成される。負極電極４１に負極面取部６６を設けることで、電極組立体４０は、全体として、負極面取部６６が連なる面取部を備えることになる。負極上端面６２とセパレータ上端面８３とは積層方向に並び、負極下端面６３とセパレータ下端面８４とは積層方向に並ぶ。負極側端面６４，６５とセパレータ側端面８５とは積層方向に並ぶ。 The outer surface of the electrode assembly 40 is formed by connecting a negative electrode 41 and a bag-shaped separator 81. By providing the negative electrode chamfered portion 66 on the negative electrode electrode 41, the electrode assembly 40 is provided with a chamfered portion in which the negative electrode chamfered portions 66 are connected as a whole. The negative electrode upper end surface 62 and the separator upper end surface 83 are arranged in the stacking direction, and the negative electrode lower end surface 63 and the separator lower end surface 84 are arranged in the stacking direction. The negative electrode side end faces 64 and 65 and the separator side end faces 85 are aligned in the stacking direction.

図１及び図２に示すように、電極組立体４０は、負極下端面６３、正極下端面７３、及び、セパレータ下端面８４が絶縁シート３０を介して底壁２３と向かい合うようにケース２０に収容されている。負極下端面６３は第１負極面となり、セパレータ下端面８４は第１セパレータ面となる。正極下端面７３は第１正極面となる。 As shown in FIGS. 1 and 2, the electrode assembly 40 is housed in the case 20 so that the negative electrode lower end surface 63, the positive electrode lower end surface 73, and the separator lower end surface 84 face the bottom wall 23 via the insulating sheet 30. Has been done. The lower end surface 63 of the negative electrode serves as the first negative electrode surface, and the lower end surface 84 of the separator serves as the first separator surface. The lower end surface 73 of the positive electrode is the first positive electrode surface.

負極側端面６４，６５、及び、セパレータ側端面８５は、絶縁シート３０を介して第１側部２６に向かい合っている。正極側端面７４，７５は、袋状セパレータ８１及び絶縁シート３０を介して第１側部２６に向かい合っている。負極側端面６４，６５、セパレータ側端面８５、及び、正極側端面７４，７５は、積層方向に延びている。負極側端面６４，６５は第２負極面となり、セパレータ側端面８５は第２セパレータ面となる。正極側端面７４，７５は第２正極面となる。 The negative electrode side end faces 64 and 65 and the separator side end face 85 face the first side portion 26 via the insulating sheet 30. The positive electrode side end faces 74 and 75 face the first side portion 26 via the bag-shaped separator 81 and the insulating sheet 30. The negative electrode side end faces 64 and 65, the separator side end face 85, and the positive electrode side end faces 74 and 75 extend in the stacking direction. The negative electrode side end faces 64 and 65 serve as the second negative electrode surface, and the separator side end face 85 serves as the second separator face. The positive electrode side end faces 74 and 75 are the second positive electrode faces.

負極面取部６６は、ケース隅部２４に向かい合っている。袋状セパレータ８１の角Ｃ２は、負極面取部６６よりもケース２０（ケース隅部２４）の内面側に位置している。積層方向から見て、袋状セパレータ８１の角Ｃ２は、負極面取部６６と、ケース隅部２４を覆う絶縁シート３０との間に位置している。ここで、ケース隅部２４の内面の半径Ｒ１は、負極面取部６６の面取寸法Ｌ４１に絶縁シート３０の厚みＴを加えた寸法よりも小さい。負極面取部６６の面取寸法Ｌ４１とは、負極下端面６３の延長線と負極側端面６４，６５の延長線とが交わる角Ｃ１１から負極下端面６３（あるいは負極側端面６４，６５）までの寸法である。負極面取部６６の面取寸法Ｌ４１を上記のようにすることで、負極面取部６６と絶縁シート３０との間には隙間が維持されやすい。 The negative electrode chamfered portion 66 faces the corner portion 24 of the case. The corner C2 of the bag-shaped separator 81 is located on the inner surface side of the case 20 (case corner portion 24) with respect to the negative electrode chamfered portion 66. When viewed from the stacking direction, the corner C2 of the bag-shaped separator 81 is located between the negative electrode chamfered portion 66 and the insulating sheet 30 covering the case corner portion 24. Here, the radius R1 of the inner surface of the case corner portion 24 is smaller than the dimension obtained by adding the thickness T of the insulating sheet 30 to the chamfering dimension L41 of the negative electrode chamfered portion 66. The chamfer dimension L41 of the negative electrode chamfered portion 66 is from the angle C11 where the extension line of the negative electrode lower end surface 63 and the extension line of the negative electrode side end faces 64, 65 intersect to the negative electrode lower end surface 63 (or the negative electrode side end faces 64, 65). It is the dimension of. By setting the chamfer dimension L41 of the negative electrode chamfered portion 66 as described above, a gap is easily maintained between the negative electrode chamfered portion 66 and the insulating sheet 30.

次に、二次電池１０の作用について説明する。
二次電池１０に衝撃や振動が加わると、負極下端面６３から絶縁シート３０に荷重が加わる。この際、負極下端面６３と負極側端面６４，６５により直角や鋭角の角が形成されている場合、角と底壁２３によって絶縁シート３０が挟まれることで、絶縁シート３０における角と接触する部位に荷重が集中しやすい。 Next, the operation of the secondary battery 10 will be described.
When an impact or vibration is applied to the secondary battery 10, a load is applied to the insulating sheet 30 from the lower end surface 63 of the negative electrode. At this time, when a right-angled or acute-angled corner is formed by the negative electrode lower end surface 63 and the negative electrode side end surfaces 64 and 65, the insulating sheet 30 is sandwiched between the corner and the bottom wall 23 and comes into contact with the corner of the insulating sheet 30. The load tends to concentrate on the part.

本実施形態では、負極下端面６３と負極側端面６４，６５とを接続している負極面取部６６を設けているため、負極下端面６３と負極側端面６４，６５とで直角や鋭角の角が形成されていない。これにより、直角や鋭角の部位と、ケース２０とで絶縁シート３０が挟まれることが抑制されている。 In the present embodiment, since the negative electrode chamfered portion 66 connecting the negative electrode lower end surface 63 and the negative electrode side end surfaces 64 and 65 is provided, the negative electrode lower end surface 63 and the negative electrode side end surfaces 64 and 65 have a right angle or an acute angle. No corners are formed. As a result, the insulating sheet 30 is prevented from being sandwiched between the right-angled or acute-angled portion and the case 20.

図７に示すように、積層方向から見て、袋状セパレータ８１の角Ｃ２は、負極面取部６６よりもケース２０の内面側に突出している。袋状セパレータ８１における負極面取部６６よりもケース２０の内面側に突出した部分は、積層方向に屈曲し、隣接する負極電極４１の負極面取部６６を覆うことになる。負極面取部６６と絶縁シート３０との間に袋状セパレータ８１が介在することで、負極面取部６６から絶縁シート３０に力が加わる際には、袋状セパレータ８１を介して絶縁シート３０に力が加わることになる。袋状セパレータ８１は、負極電極４１に比べて軟らかく、袋状セパレータ８１がクッションとして機能することになる。 As shown in FIG. 7, when viewed from the stacking direction, the corner C2 of the bag-shaped separator 81 projects toward the inner surface side of the case 20 with respect to the negative electrode chamfered portion 66. The portion of the bag-shaped separator 81 that protrudes toward the inner surface side of the case 20 from the negative electrode chamfered portion 66 bends in the stacking direction and covers the negative electrode chamfered portion 66 of the adjacent negative electrode electrode 41. By interposing the bag-shaped separator 81 between the negative electrode chamfered portion 66 and the insulating sheet 30, when a force is applied to the insulating sheet 30 from the negative electrode chamfered portion 66, the insulating sheet 30 is interposed via the bag-shaped separator 81. Will be added to the force. The bag-shaped separator 81 is softer than the negative electrode electrode 41, and the bag-shaped separator 81 functions as a cushion.

なお、二次電池１０に衝撃や振動が加わった場合の二次電池１０の作用について説明したが、二次電池１０の充放電に伴う負極電極４１の膨張によって負極電極４１から絶縁シート３０に荷重が加わる際にも同様の作用が生じる。 Although the operation of the secondary battery 10 when an impact or vibration is applied to the secondary battery 10 has been described, a load is applied from the negative electrode electrode 41 to the insulating sheet 30 due to the expansion of the negative electrode electrode 41 due to the charging and discharging of the secondary battery 10. The same effect occurs when is added.

したがって、上記実施形態によれば、以下の効果を得ることができる。
（１）負極電極４１は、負極面取部６６を備える。ケース２０内での電極組立体４０の移動により負極面取部６６が絶縁シート３０に接したとしても、直角や鋭角の部位が絶縁シート３０に接する場合に比べて荷重の集中が少ない。したがって、絶縁シート３０が損傷することが抑制される。 Therefore, according to the above embodiment, the following effects can be obtained.
(1) The negative electrode electrode 41 includes a negative electrode chamfered portion 66. Even if the negative electrode chamfered portion 66 comes into contact with the insulating sheet 30 due to the movement of the electrode assembly 40 in the case 20, the load concentration is less than when the right-angled or acute-angled portion comes into contact with the insulating sheet 30. Therefore, damage to the insulating sheet 30 is suppressed.

更に、袋状セパレータ８１の一部が負極面取部６６と絶縁シート３０との間に介在するようにしている。負極面取部６６から絶縁シート３０に加わる力はセパレータ片８２によって軽減されるため、絶縁シート３０の損傷は更に抑制されている。したがって、ケース２０と電極組立体４０との絶縁が維持されやすく、ケース２０と電極組立体４０との短絡が抑制されている。 Further, a part of the bag-shaped separator 81 is interposed between the negative electrode chamfered portion 66 and the insulating sheet 30. Since the force applied to the insulating sheet 30 from the negative electrode chamfered portion 66 is reduced by the separator piece 82, damage to the insulating sheet 30 is further suppressed. Therefore, the insulation between the case 20 and the electrode assembly 40 is easily maintained, and the short circuit between the case 20 and the electrode assembly 40 is suppressed.

（２）正極電極５１は、正極面取部７６を備える。負極電極４１の場合と同様に、ケース２０内での電極組立体４０の移動に伴い、正極電極５１の角により絶縁シート３０が損傷することが抑制されている。また、正極面取部７６を設けることで、負極電極４１と正極電極５１の容量比が維持されやすい。 (2) The positive electrode electrode 51 includes a positive electrode chamfered portion 76. Similar to the case of the negative electrode 41, damage to the insulating sheet 30 is suppressed by the corners of the positive electrode 51 as the electrode assembly 40 moves in the case 20. Further, by providing the positive electrode chamfered portion 76, the volume ratio between the negative electrode electrode 41 and the positive electrode electrode 51 can be easily maintained.

（３）絶縁シート３０と負極面取部６６との間の隙間が維持されやすいようにしている。このため、負極面取部６６が絶縁シート３０に接触することを抑制することができ、絶縁シート３０の損傷を更に抑制することができる。 (3) The gap between the insulating sheet 30 and the negative electrode chamfered portion 66 is easily maintained. Therefore, it is possible to prevent the negative electrode chamfered portion 66 from coming into contact with the insulating sheet 30, and it is possible to further suppress damage to the insulating sheet 30.

なお、実施形態は、以下のように変更してもよい。
○ケース隅部２４の内面の半径Ｒ１は、負極面取部６６の面取寸法Ｌ４１に絶縁シート３０の厚みＴを加えた寸法以上であってもよい。この場合であっても、直角や鋭角の部位が絶縁シート３０に接する場合に比べると絶縁シート３０が損傷しにくい。 The embodiment may be changed as follows.
The radius R1 of the inner surface of the corner portion 24 of the case may be equal to or larger than the chamfer dimension L41 of the negative electrode chamfered portion 66 plus the thickness T of the insulating sheet 30. Even in this case, the insulating sheet 30 is less likely to be damaged as compared with the case where a right-angled or acute-angled portion is in contact with the insulating sheet 30.

○正極電極５１は、正極面取部７６を備えていなくてもよい。即ち、正極下端面７３と正極側端面７４，７５とは直角に交わっていてもよい。リチウムイオン電池においては、正極電極５１の外形寸法は負極電極４１の外形寸法よりも小さい。正極電極５１は負極電極４１に比べて絶縁シート３０に接しにくいため、正極電極５１が正極面取部７６を備えていなくても、絶縁シート３０の損傷を抑制することができる。 ○ The positive electrode electrode 51 does not have to include the positive electrode chamfered portion 76. That is, the lower end surface 73 of the positive electrode and the end surfaces 74 and 75 on the positive electrode side may intersect at right angles. In the lithium ion battery, the external dimensions of the positive electrode 51 are smaller than the external dimensions of the negative electrode 41. Since the positive electrode 51 is less likely to come into contact with the insulating sheet 30 than the negative electrode 41, damage to the insulating sheet 30 can be suppressed even if the positive electrode 51 does not include the positive electrode chamfered portion 76.

○図８に示すように、負極面取部６６は、ケース隅部２４の内面に向けて膨らむアール状であってもよい。この場合、面取寸法とは、負極面取部６６の半径Ｒ２となる。ケース隅部２４の内面の半径は、負極面取部６６の半径に絶縁シート３０の厚みＴを加えた寸法よりも小さくてもよい。 ○ As shown in FIG. 8, the negative electrode chamfered portion 66 may have a rounded shape that bulges toward the inner surface of the case corner portion 24. In this case, the chamfered dimension is the radius R2 of the negative electrode chamfered portion 66. The radius of the inner surface of the case corner 24 may be smaller than the radius of the negative electrode chamfered portion 66 plus the thickness T of the insulating sheet 30.

○負極電極４１は、負極上端面６２と負極側端面６４，６５との間に位置し負極上端面６２と負極側端面６４，６５とを接続する面取部を備えていてもよい。また、正極電極５１は、正極上端面７２と正極側端面７４，７５との間に位置し正極上端面７２と正極側端面７４，７５とを接続する面取部を備えていてもよい。 The negative electrode electrode 41 may be provided with a chamfered portion located between the negative electrode upper end surface 62 and the negative electrode side end surfaces 64, 65 and connecting the negative electrode upper end surface 62 and the negative electrode side end surfaces 64, 65. Further, the positive electrode electrode 51 may be provided with a chamfered portion located between the positive electrode upper end surface 72 and the positive electrode side end surfaces 74 and 75 and connecting the positive electrode upper end surface 72 and the positive electrode side end surfaces 74 and 75.

○複数の負極電極４１のうちの一部が負極面取部６６を備えていなくてもよい。この場合であっても、全ての負極電極４１が負極面取部６６を備えていない場合に比べ、絶縁シート３０の損傷を抑制することができる。 ○ A part of the plurality of negative electrode electrodes 41 may not be provided with the negative electrode chamfered portion 66. Even in this case, damage to the insulating sheet 30 can be suppressed as compared with the case where all the negative electrode electrodes 41 do not have the negative electrode chamfered portion 66.

○ケース２０の形状は、電極組立体４０を収容することができればどのような形状でもよい。
○ケース隅部２４の内面は、アール状に限られず、直角状などでもよい。 The shape of the case 20 may be any shape as long as it can accommodate the electrode assembly 40.
○ The inner surface of the corner 24 of the case is not limited to a rounded shape, but may be a right angle shape or the like.

○負極金属箔４４の一方の面にのみ負極活物質層４５が設けられていてもよい。正極金属箔５４の一方の面にのみ正極活物質層５５が設けられていてもよい。
○負極本体４２と正極本体５２の外形寸法は同一でもよい。 ○ The negative electrode active material layer 45 may be provided only on one surface of the negative electrode metal foil 44. The positive electrode active material layer 55 may be provided only on one surface of the positive electrode metal foil 54.
○ The external dimensions of the negative electrode body 42 and the positive electrode body 52 may be the same.

○セパレータ片８２同士は溶着されていなくてもよい。
○蓄電装置は、キャパシタでもよい。 ○ Separator pieces 82 may not be welded to each other.
○ The power storage device may be a capacitor.

Ｃ２…角、１０…二次電池（蓄電装置）、２０…ケース、２３…底壁、２４…ケース隅部、２５…側壁、３０…絶縁シート、４０…電極組立体、４１…負極電極、４２…負極本体、４３…負極タブ、４４…負極金属箔、４５…負極活物質層、５１…正極電極、５２…正極本体、５３…正極タブ、５４…正極金属箔、５５…正極活物質層、６３…負極下端面（第１負極面）、６４，６５…負極側端面（第２負極面）、６６…負極面取部、７３…正極下端面（第１正極面）、７４，７５…正極側端面（第２正極面）、７６…正極面取部、８２…セパレータ片（セパレータ）、８４…セパレータ下端面（第１セパレータ面）、８５…セパレータ側端面（第２セパレータ面）。 C2 ... corner, 10 ... secondary battery (power storage device), 20 ... case, 23 ... bottom wall, 24 ... case corner, 25 ... side wall, 30 ... insulating sheet, 40 ... electrode assembly, 41 ... negative electrode electrode, 42 ... Negative electrode body, 43 ... Negative electrode tab, 44 ... Negative electrode metal foil, 45 ... Negative electrode active material layer, 51 ... Positive electrode, 52 ... Positive electrode body, 53 ... Positive electrode tab, 54 ... Positive electrode metal foil, 55 ... Positive electrode active material layer, 63 ... Negative electrode lower end surface (first negative electrode surface), 64, 65 ... Negative electrode side end surface (second negative electrode surface), 66 ... Negative electrode chamfered portion, 73 ... Positive electrode lower end surface (first positive electrode surface), 74, 75 ... Positive electrode Side end surface (second positive electrode surface), 76 ... positive electrode chamfered portion, 82 ... separator piece (separator), 84 ... separator lower end surface (first separator surface), 85 ... separator side end surface (second separator surface).

Claims (5)

複数の正極電極と複数の負極電極とを前記正極電極と前記負極電極との間に配置したセパレータで絶縁した状態で交互に積層した電極組立体と、
前記電極組立体が収容されたケースと、
前記電極組立体と前記ケースとの間に介在し、前記電極組立体と前記ケースとを絶縁している絶縁シートと、を備え、
前記ケースは、底壁と、側壁と、前記底壁と前記側壁とを繋ぐケース隅部と、を備え、
前記負極電極は、負極金属箔に負極活物質層を設けた負極本体と、前記負極金属箔からなり、前記負極本体から延びる負極タブと、を備え、
前記負極本体は、前記絶縁シートを介して前記底壁に向かい合う第１負極面と、前記絶縁シートを介して前記側壁に向かい合う第２負極面と、前記第１負極面と前記第２負極面との間に位置して前記第１負極面と前記第２負極面とを接続し、前記絶縁シートを介して前記ケース隅部に向かい合う負極面取部と、を備え、
前記セパレータは、前記絶縁シートを介して前記底壁に向かい合う第１セパレータ面と、前記絶縁シートを介して前記側壁に向かい合い、前記第１セパレータ面に接続する第２セパレータ面と、を備え、
前記正極電極と前記負極電極との積層方向から見て、前記負極本体の外形は前記セパレータの外形内に収まり、
前記絶縁シートと前記負極面取部との間に隙間を有し、
前記第１セパレータ面と前記第２セパレータ面とが接続する角は、前記隙間に位置するとともに前記負極面取部を覆う蓄電装置。 An electrode assembly in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated in a state of being insulated by a separator arranged between the positive electrode and the negative electrode.
A case containing the electrode assembly and
An insulating sheet that is interposed between the electrode assembly and the case and that insulates the electrode assembly and the case is provided.
The case includes a bottom wall, a side wall, and a case corner connecting the bottom wall and the side wall.
The negative electrode includes a negative electrode body provided with a negative electrode active material layer on the negative electrode metal foil, and a negative electrode tab composed of the negative electrode metal foil and extending from the negative electrode body.
The negative electrode body includes a first negative electrode surface facing the bottom wall via the insulating sheet, a second negative electrode surface facing the side wall via the insulating sheet, the first negative electrode surface, and the second negative electrode surface. A negative electrode chamfering portion that connects the first negative electrode surface and the second negative electrode surface and faces the corner of the case via the insulating sheet is provided between the two.
The separator includes a first separator surface facing the bottom wall via the insulating sheet, and a second separator surface facing the side wall via the insulating sheet and connecting to the first separator surface.
The outer shape of the negative electrode body fits within the outer shape of the separator when viewed from the stacking direction of the positive electrode and the negative electrode.
There is a gap between the insulating sheet and the negative electrode chamfered portion,
A power storage device in which the angle at which the first separator surface and the second separator surface are connected is located in the gap and covers the negative electrode chamfered portion. 前記正極電極は、正極金属箔に正極活物質層を設けた正極本体と、前記正極金属箔からなり、前記正極本体から延びる正極タブと、を備え、
前記正極本体は、前記絶縁シートを介して前記底壁に向かい合う第１正極面と、前記絶縁シートを介して前記側壁に向かい合う第２正極面と、前記第１正極面と前記第２正極面の間に位置して前記第１正極面と前記第２正極面とを接続し、前記絶縁シートを介して前記ケース隅部に向かい合う正極面取部と、を備える請求項１に記載の蓄電装置。 The positive electrode includes a positive electrode body provided with a positive electrode active material layer on the positive electrode metal foil, and a positive electrode tab composed of the positive electrode metal foil and extending from the positive electrode body.
The positive electrode body includes a first positive electrode surface facing the bottom wall via the insulating sheet, a second positive electrode surface facing the side wall via the insulating sheet, and a first positive electrode surface and the second positive electrode surface. The power storage device according to claim 1, further comprising a positive electrode chamfering portion that connects the first positive electrode surface and the second positive electrode surface and faces the corner of the case via the insulating sheet. 前記ケース隅部の内面は、アール状であり、
前記負極面取部は、前記ケース隅部の内面に向けて膨らむアール状であり、
前記ケース隅部の前記内面の半径は、前記負極面取部の半径に前記絶縁シートの厚みを加えた寸法よりも小さい請求項１又は請求項２に記載の蓄電装置。 The inner surface of the corner of the case is rounded and has a rounded shape.
The negative electrode chamfered portion has a rounded shape that bulges toward the inner surface of the corner of the case.
The power storage device according to claim 1 or 2, wherein the radius of the inner surface of the corner of the case is smaller than the radius of the negative electrode chamfered portion plus the thickness of the insulating sheet. 前記第１セパレータ面と前記第２セパレータ面とが接続する角のうち、前記負極面取部よりも前記ケースの内面側に突出した部分は、前記積層方向に屈曲し、隣接する負極電極の前記負極面取部を覆う請求項１〜３のうちいずれか一項に記載の蓄電装置。 Of the angles connecting the first separator surface and the second separator surface, a portion protruding toward the inner surface side of the case from the negative electrode chamfered portion is bent in the stacking direction, and the adjacent negative electrode electrode is said to have the same angle. The power storage device according to any one of claims 1 to 3, which covers the negative electrode chamfered portion. 前記ケースは、前記底壁と、前記側壁と、前記ケース隅部と、を備える本体を有し、 The case has a body comprising the bottom wall, the side walls, and the corners of the case.
前記絶縁シートは、前記本体の内面に沿っている請求項１〜４のうちいずれか一項に記載の蓄電装置。 The power storage device according to any one of claims 1 to 4, wherein the insulating sheet is along the inner surface of the main body.
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