JP2022031997A - Sealed battery - Google Patents

Sealed battery Download PDF

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JP2022031997A
JP2022031997A JP2018235408A JP2018235408A JP2022031997A JP 2022031997 A JP2022031997 A JP 2022031997A JP 2018235408 A JP2018235408 A JP 2018235408A JP 2018235408 A JP2018235408 A JP 2018235408A JP 2022031997 A JP2022031997 A JP 2022031997A
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thin
sealing body
valve
battery case
battery
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Inventor
政幹 吉田
Masamiki Yoshida
仰 奥谷
Aogu Okuya
嵩広 野上
Takahiro Nogami
曉 高野
Akira Takano
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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Priority to JP2018235408A priority Critical patent/JP2022031997A/en
Priority to PCT/JP2019/044540 priority patent/WO2020129479A1/en
Publication of JP2022031997A publication Critical patent/JP2022031997A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/552—Terminals characterised by their shape
    • H01M50/559—Terminals adapted for cells having curved cross-section, e.g. round, elliptic or button cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/30—Arrangements for facilitating escape of gases
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/574—Devices or arrangements for the interruption of current
    • 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

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Gas Exhaust Devices For Batteries (AREA)
  • Connection Of Batteries Or Terminals (AREA)
  • Sealing Battery Cases Or Jackets (AREA)

Abstract

To provide a sealed battery including a sealed body capable of ensuring sufficient battery safety even while a structure can be simplified.SOLUTION: A sealed battery in an embodiment includes: a battery case including a tubular outer can with a bottom and a sealed body sealing an opening of the outer can; and electrode bodies accommodated in the battery case. The sealed body includes a metal plate. The metal plate has: a thin wall part formed in a ring shape; a valve part having a convex shape inside the battery case, and surrounded by the thin wall part which is reversed so as to protrude to the outside of the battery case when an internal pressure of the battery case reaches a reversal pressure R; and an annular part located at the outside of the thin wall part. The sealed body is configured so that the thin wall part breaks at the same time as the valve part is reversed.SELECTED DRAWING: Figure 2

Description

本開示は、密閉電池に関する。 The present disclosure relates to sealed batteries.

従来、有底筒状の外装缶、及び外装缶の開口部を塞ぐ封口体を含む電池ケースを備えた密閉電池が広く知られている（例えば、特許文献１参照）。特許文献１に開示されるように、封口体は、例えば内部端子板、下弁体、絶縁部材、上弁体、及びキャップがこの順に積層された構造を有する。下弁体と上弁体は各々の中央部で互いに接続され、各々の周縁部の間には絶縁部材が介在している。この場合、電池に異常が発生して電池ケースの内圧が上昇すると、下弁体が上弁体をキャップ側に押し上げるように変形して破断することにより、下弁体と上弁体の間の電流経路が遮断される。さらに内圧が上昇すると、上弁体が破断し、キャップの開口部からガスが排出される。 Conventionally, a sealed battery including a bottomed tubular outer can and a battery case including a sealing body for closing the opening of the outer can is widely known (see, for example, Patent Document 1). As disclosed in Patent Document 1, the sealing body has a structure in which, for example, an internal terminal plate, a lower valve body, an insulating member, an upper valve body, and a cap are laminated in this order. The lower valve body and the upper valve body are connected to each other at the central portion thereof, and an insulating member is interposed between the peripheral portions thereof. In this case, when an abnormality occurs in the battery and the internal pressure of the battery case rises, the lower valve body deforms and breaks so as to push the upper valve body toward the cap side, thereby breaking between the lower valve body and the upper valve body. The current path is cut off. When the internal pressure further rises, the upper valve body breaks and gas is discharged from the opening of the cap.

特開２０１８－０１４１６０号公報Japanese Unexamined Patent Publication No. 2018-014160

上述のように、従来の封口体によれば、電池に異常が発生して電池ケースの内圧が上昇したときに、電池の電流経路が遮断されると共に、ガスの排出経路が形成され、異常発生時における電池の安全性が確保される。しかし、従来の封口体は、弁体の破断により大きなガスの排出経路を確保することが困難である。さらに、従来の封口体は安全性を確保するため、部品点数が多く構造が複雑である。そのため、電池の製造コストや体積エネルギー密度の観点から封口体の構造の単純化が望まれている。 As described above, according to the conventional sealing body, when an abnormality occurs in the battery and the internal pressure of the battery case rises, the current path of the battery is cut off and the gas discharge path is formed, so that the abnormality occurs. The safety of the battery at the time is ensured. However, in the conventional sealing body, it is difficult to secure a large gas discharge path due to the breakage of the valve body. Further, the conventional sealing body has a large number of parts and a complicated structure in order to ensure safety. Therefore, it is desired to simplify the structure of the sealing body from the viewpoint of battery manufacturing cost and volume energy density.

本開示の一態様である密閉電池は、有底筒状の外装缶、及び前記外装缶の開口部を塞ぐ封口体を含む電池ケースと、前記電池ケース内に収容された電極体とを備える密閉電池であって、前記封口体は金属板を含み、前記金属板は、環状に形成された薄肉部と、前記電池ケースの内側に凸の形状を有し、前記電池ケースの内圧が反転圧Ｒに達したときに当該ケースの外側に凸となるように反転する、前記薄肉部に囲まれた弁部と、前記薄肉部の外側に位置する環状部とを有し、前記封口体は、前記弁部の反転と同時に前記薄肉部が破断するように構成されている。 The sealed battery according to one aspect of the present disclosure includes a bottomed tubular outer can, a battery case including a sealing body for closing the opening of the outer can, and an electrode body housed in the battery case. In the battery, the sealing body includes a metal plate, and the metal plate has a thin-walled portion formed in an annular shape and a convex shape inside the battery case, and the internal pressure of the battery case is a reversal pressure R. The sealing body has a valve portion surrounded by the thin-walled portion and an annular portion located outside the thin-walled portion, which is inverted so as to be convex to the outside of the case when the temperature is reached. The thin-walled portion is configured to break at the same time as the valve portion is inverted.

本開示の一態様によれば、構造の単純化が可能でありながら、電池の安全性を十分に確保できる封口体を備えた密閉電池を提供することができる。本開示に係る密閉電池によれば、例えば、弁部が環状部から完全に切り離されることにより、大きなガスの排出経路が形成される。さらに、１枚の金属板で電流遮断機構を構成することにより、封口体の部品点数を削減することができる。 According to one aspect of the present disclosure, it is possible to provide a sealed battery having a sealing body capable of sufficiently ensuring the safety of the battery while simplifying the structure. According to the sealed battery according to the present disclosure, for example, the valve portion is completely separated from the annular portion, so that a large gas discharge path is formed. Further, by forming the current cutoff mechanism with one metal plate, the number of parts of the sealing body can be reduced.

実施形態の一例である密閉電池の断面図である。It is sectional drawing of the closed battery which is an example of Embodiment. 実施形態の一例である封口体の断面図である。It is sectional drawing of the sealing body which is an example of an embodiment. 実施形態の一例である封口体の平面図である。It is a top view of the sealing body which is an example of an embodiment. 実施形態の他の一例である封口体の断面図である。It is sectional drawing of the sealing body which is another example of Embodiment. 実施形態の一例である封口体が反転・ベントする様子を示す図である。It is a figure which shows the mode that the sealing body which is an example of an embodiment inverts and vents. 従来技術の一例である封口体が反転・ベントする様子を示す図である。It is a figure which shows the state which the sealing body which is an example of a prior art reverses and vents.

本発明者らは、上記の課題を解決すべく鋭意検討した結果、弁部の反転と同時に薄肉部を破断させる、即ち弁部の反転を利用して薄肉部を破断させる新たな設計思想の封口体を見出した。当該設計思想によれば、封口体の構造の単純化が可能でありながら、電池の安全性を確保することができる。 As a result of diligent studies to solve the above problems, the present inventors have sealed a new design concept in which the thin-walled portion is broken at the same time as the valve portion is inverted, that is, the thin-walled portion is broken by utilizing the inversion of the valve portion. I found my body. According to the design concept, the safety of the battery can be ensured while the structure of the sealing body can be simplified.

以下、本開示の実施形態の一例について詳細に説明する。以下では、本開示に係る密閉電池の実施形態の一例として、巻回型の電極体１４が円筒形状の電池ケース１５に収容された円筒形電池を例示するが、電池は角形の電池ケースを備えた角形電池であってもよい。また、電極体は、複数の正極と複数の負極がセパレータを介して交互に積層されてなる積層型であってもよい。本明細書では、説明の便宜上、電池ケース１５の封口体１７側を「上」、外装缶１６の底部側を「下」として説明する。 Hereinafter, an example of the embodiment of the present disclosure will be described in detail. In the following, as an example of the embodiment of the sealed battery according to the present disclosure, a cylindrical battery in which the wound electrode body 14 is housed in a cylindrical battery case 15 will be illustrated, but the battery includes a square battery case. It may be a rectangular battery. Further, the electrode body may be a laminated type in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via a separator. In this specification, for convenience of explanation, the sealing body 17 side of the battery case 15 is referred to as “top”, and the bottom side of the outer can 16 is referred to as “bottom”.

図１は、実施形態の一例である密閉電池１０の断面図である。図１に例示するように、密閉電池１０は、有底筒状の外装缶１６、及び外装缶１６の開口部を塞ぐ封口体１７を含む電池ケース１５と、電池ケース１５内に収容された電極体１４とを備える。また、電池ケース１５内には電解質が収容されている。電極体１４は、正極１１と、負極１２と、正極１１及び負極１２の間に介在するセパレータ１３とを含む。電極体１４は、正極１１と負極１２がセパレータ１３を介して巻回されてなる巻回構造を有する。また、密閉電池１０は、外装缶１６と封口体１７との間に配置される樹脂製のガスケット２３を備える。 FIG. 1 is a cross-sectional view of a closed battery 10 which is an example of an embodiment. As illustrated in FIG. 1, the sealed battery 10 includes a bottomed tubular outer can 16 and a battery case 15 including a sealing body 17 that closes an opening of the outer can 16, and electrodes housed in the battery case 15. It has a body 14. Further, the electrolyte is housed in the battery case 15. The electrode body 14 includes a positive electrode 11, a negative electrode 12, and a separator 13 interposed between the positive electrode 11 and the negative electrode 12. The electrode body 14 has a winding structure in which a positive electrode 11 and a negative electrode 12 are wound via a separator 13. Further, the sealed battery 10 includes a resin gasket 23 arranged between the outer can 16 and the sealing body 17.

電解質は、水系電解質、非水電解質のいずれであってもよい。好適な密閉電池１０の一例は、非水電解質を用いた、リチウムイオン電池等の非水電解質二次電池である。非水電解質は、例えば非水溶媒と、非水溶媒に溶解した電解質塩とを含む。非水溶媒には、エステル類、エーテル類、ニトリル類、アミド類、及びこれらの２種以上の混合溶媒等が用いられる。非水溶媒は、これら溶媒の水素の少なくとも一部をフッ素等のハロゲン原子で置換したハロゲン置換体を含有していてもよい。なお、非水電解質は液体電解質に限定されず、ゲル状ポリマー等を用いた固体電解質であってもよい。電解質塩には、ＬｉＰＦ6等のリチウム塩が使用される。 The electrolyte may be either an aqueous electrolyte or a non-aqueous electrolyte. An example of a suitable sealed battery 10 is a non-aqueous electrolyte secondary battery such as a lithium ion battery using a non-aqueous electrolyte. The non-aqueous electrolyte includes, for example, a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. As the non-aqueous solvent, esters, ethers, nitriles, amides, a mixed solvent of two or more of these, and the like are used. The non-aqueous solvent may contain a halogen-substituted product in which at least a part of hydrogen in these solvents is substituted with a halogen atom such as fluorine. The non-aqueous electrolyte is not limited to the liquid electrolyte, and may be a solid electrolyte using a gel-like polymer or the like. As the electrolyte salt, a lithium salt such as LiPF 6 is used.

電極体１４は、長尺状の正極１１と、長尺状の負極１２と、長尺状の２枚のセパレータ１３と、正極１１に接合された正極リード２０と、負極１２に接合された負極リード２１とを有する。負極１２は、リチウムの析出を抑制するために、正極１１よりも一回り大きな寸法で形成される。即ち、負極１２は、正極１１より長手方向及び短手方向（上下方向）に長く形成される。２枚のセパレータ１３は、少なくとも正極１１よりも一回り大きな寸法で形成され、例えば正極１１を挟むように配置される。 The electrode body 14 includes a long positive electrode 11, a long negative electrode 12, two long separators 13, a positive electrode lead 20 bonded to the positive electrode 11, and a negative electrode bonded to the negative electrode 12. It has a lead 21 and. The negative electrode 12 is formed to have a size one size larger than that of the positive electrode 11 in order to suppress the precipitation of lithium. That is, the negative electrode 12 is formed longer than the positive electrode 11 in the longitudinal direction and the lateral direction (vertical direction). The two separators 13 are formed at least one size larger than the positive electrode 11, and are arranged so as to sandwich the positive electrode 11, for example.

正極１１は、正極芯体と、正極芯体の両面に設けられた正極合材層とを有する。正極芯体には、アルミニウム、アルミニウム合金など正極１１の電位範囲で安定な金属の箔、当該金属を表層に配置したフィルム等を用いることができる。正極合材層は、正極活物質、アセチレンブラック等の導電材、及びポリフッ化ビニリデン（ＰＶｄＦ）等の結着材を含む。正極１１は、正極芯体上に正極活物質、導電材、及び結着材等を含む正極合材スラリーを塗布し、塗膜を乾燥させた後、圧縮して正極合材層を正極芯体の両面に形成することにより作製できる。 The positive electrode 11 has a positive electrode core and a positive electrode mixture layer provided on both sides of the positive electrode core. As the positive electrode core, a foil of a metal stable in the potential range of the positive electrode 11 such as aluminum or an aluminum alloy, a film in which the metal is arranged on the surface layer, or the like can be used. The positive electrode mixture layer contains a positive electrode active material, a conductive material such as acetylene black, and a binder such as polyvinylidene fluoride (PVdF). For the positive electrode 11, a positive electrode mixture slurry containing a positive electrode active material, a conductive material, a binder, and the like is applied onto the positive electrode core, the coating film is dried, and then compressed to form a positive electrode mixture layer. It can be manufactured by forming it on both sides of.

正極活物質には、例えばリチウム遷移金属複合酸化物が用いられる。リチウム遷移金属複合酸化物に含有される金属元素としては、Ｎｉ、Ｃｏ、Ｍｎ、Ａｌ、Ｂ、Ｍｇ、Ｔｉ、Ｖ、Ｃｒ、Ｆｅ、Ｃｕ、Ｚｎ、Ｇａ、Ｓｒ、Ｚｒ、Ｎｂ、Ｉｎ、Ｓｎ、Ｔａ、Ｗ等が挙げられる。好適なリチウム遷移金属複合酸化物の一例は、Ｎｉ、Ｃｏ、Ｍｎの少なくとも１種を含有するリチウム金属複合酸化物である。具体例としては、Ｎｉ、Ｃｏ、Ｍｎを含有する複合酸化物、Ｎｉ、Ｃｏ、Ａｌを含有する複合酸化物が挙げられる。 For example, a lithium transition metal composite oxide is used as the positive electrode active material. Metallic elements contained in the lithium transition metal composite oxide include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In and Sn. , Ta, W and the like. An example of a suitable lithium transition metal composite oxide is a lithium metal composite oxide containing at least one of Ni, Co, and Mn. Specific examples include a composite oxide containing Ni, Co and Mn, and a composite oxide containing Ni, Co and Al.

負極１２は、負極芯体と、負極芯体の両面に設けられた負極合材層とを有する。負極芯体には、銅、銅合金など負極１２の電位範囲で安定な金属の箔、当該金属を表層に配置したフィルム等を用いることができる。負極合材層は、負極活物質、及びスチレンブタジエンゴム（ＳＢＲ）等の結着材を含む。負極１２は、負極芯体上に負極活物質、及び結着材等を含む負極合材スラリーを塗布し、塗膜を乾燥させた後、圧縮して負極合材層を負極芯体の両面に形成することにより作製できる。 The negative electrode 12 has a negative electrode core and a negative electrode mixture layer provided on both sides of the negative electrode core. As the negative electrode core, a foil of a metal stable in the potential range of the negative electrode 12 such as copper or a copper alloy, a film in which the metal is arranged on the surface layer, or the like can be used. The negative electrode mixture layer contains a negative electrode active material and a binder such as styrene butadiene rubber (SBR). The negative electrode 12 is formed by applying a negative electrode mixture slurry containing a negative electrode active material, a binder and the like on the negative electrode core, drying the coating film, and then compressing the negative electrode mixture layer on both sides of the negative electrode core. It can be produced by forming.

負極活物質には、例えば鱗片状黒鉛、塊状黒鉛、土状黒鉛等の天然黒鉛、塊状人造黒鉛、黒鉛化メソフェーズカーボンマイクロビーズ等の人造黒鉛などの黒鉛が用いられる。負極活物質には、Ｓｉ、Ｓｎ等のリチウムと合金化する金属、当該金属を含有する合金、当該金属を含有する化合物等が用いられてもよく、これらが黒鉛と併用されてもよい。当該化合物の具体例としては、ＳｉＯx（０．５≦ｘ≦１．６）で表されるケイ素化合物が挙げられる。 As the negative electrode active material, for example, natural graphite such as scaly graphite, lumpy graphite, earthy graphite, lumpy artificial graphite, and graphite such as artificial graphite such as graphitized mesophase carbon microbeads are used. As the negative electrode active material, a metal alloying with lithium such as Si and Sn, an alloy containing the metal, a compound containing the metal, and the like may be used, and these may be used in combination with graphite. Specific examples of the compound include a silicon compound represented by SiO x (0.5 ≦ x ≦ 1.6).

電極体１４の上下には、絶縁板１８，１９がそれぞれ配置される。図１に示す例では、正極１１に取り付けられた正極リード２０が絶縁板１８の貫通孔を通って封口体１７側に延び、負極１２に取り付けられた負極リード２１が絶縁板１９の外側を通って外装缶１６の底部側に延びている。正極リード２０は、封口体１７の電池ケース１５の内側を向いた内面に溶接等で接続され、封口体１７が正極外部端子となる。負極リード２１は、外装缶１６の底部内面に溶接等で接続され、外装缶１６が負極外部端子となる。 Insulating plates 18 and 19 are arranged above and below the electrode body 14, respectively. In the example shown in FIG. 1, the positive electrode lead 20 attached to the positive electrode 11 extends toward the sealing body 17 through the through hole of the insulating plate 18, and the negative electrode lead 21 attached to the negative electrode 12 passes through the outside of the insulating plate 19. It extends to the bottom side of the outer can 16. The positive electrode lead 20 is connected to the inner surface of the battery case 15 of the sealing body 17 facing inward by welding or the like, and the sealing body 17 serves as a positive electrode external terminal. The negative electrode lead 21 is connected to the inner surface of the bottom of the outer can 16 by welding or the like, and the outer can 16 serves as a negative electrode external terminal.

電池ケース１５は、上述の通り、有底筒状の外装缶１６と、外装缶１６の開口部を塞ぐ封口体１７とで構成される。外装缶１６は、有底円筒形状の金属製容器である。外装缶１６と封口体１７との間にはガスケット２３が設けられ、電池ケース１５の内部空間が密閉される。外装缶１６は、例えば側面部の外側からのスピニング加工により側面部に形成された、封口体１７を支持する溝入部２２を有する。溝入部２２は、外装缶１６の周方向に沿って環状に形成されることが好ましく、その上面で封口体１７を支持する。また、外装缶１６の上端部は、電池ケース１５の内側に折り曲げられ封口体１７の周縁部に加締められている。 As described above, the battery case 15 is composed of a bottomed tubular outer can 16 and a sealing body 17 that closes the opening of the outer can 16. The outer can 16 is a metal container having a bottomed cylindrical shape. A gasket 23 is provided between the outer can 16 and the sealing body 17, and the internal space of the battery case 15 is sealed. The outer can 16 has a grooved portion 22 that supports the sealing body 17 and is formed on the side surface portion by, for example, spinning from the outside of the side surface portion. The grooved portion 22 is preferably formed in an annular shape along the circumferential direction of the outer can 16, and the sealing body 17 is supported on the upper surface thereof. Further, the upper end portion of the outer can 16 is bent inside the battery case 15 and crimped to the peripheral edge portion of the sealing body 17.

以下、図２～図５Ｂをさらに参照しながら、封口体１７について詳説する。図２は封口体１７の断面図、図３は封口体１７の平面図である。図４は、図２に例示する封口体１７の変形例を示す図である。 Hereinafter, the sealing body 17 will be described in detail with reference to FIGS. 2 to 5B. FIG. 2 is a cross-sectional view of the sealing body 17, and FIG. 3 is a plan view of the sealing body 17. FIG. 4 is a diagram showing a modified example of the sealing body 17 illustrated in FIG. 2.

図２及び図３に例示するように、封口体１７は、環状に形成された薄肉部３４を有する。封口体１７は、薄肉部３４に囲まれた弁部３０と、薄肉部３４の外側に位置する環状部３１とを有する。即ち、弁部３０と環状部３１は、薄肉部３４によって区分けされている。薄肉部３４は、弁部３０及び環状部３１よりも厚みが薄い部分であって、電池に異常が発生して電池ケース１５の内圧が上昇したときに他の部分より優先的に破断する易破断部である。封口体１７は、電池ケース１５の内側に折り曲げられた外装缶１６の上端部及び溝入部２２によって環状部３１が挟持されることで、ガスケット２３を介して外装缶１６に固定される。 As illustrated in FIGS. 2 and 3, the sealing body 17 has a thin-walled portion 34 formed in an annular shape. The sealing body 17 has a valve portion 30 surrounded by the thin-walled portion 34 and an annular portion 31 located outside the thin-walled portion 34. That is, the valve portion 30 and the annular portion 31 are separated by the thin-walled portion 34. The thin-walled portion 34 is a portion thinner than the valve portion 30 and the annular portion 31, and is easily broken to break preferentially over the other portions when an abnormality occurs in the battery and the internal pressure of the battery case 15 rises. It is a department. The sealing body 17 is fixed to the outer can 16 via the gasket 23 by sandwiching the annular portion 31 by the upper end portion and the grooved portion 22 of the outer can 16 bent inside the battery case 15.

弁部３０は電池ケース１５の内側に凸の形状（下凸形状）を有し、電池ケース１５の内圧が所定の反転圧Ｒに達したときに当該ケースの外側に凸（上凸形状）となるように反転する。そして、弁部３０の反転と同時に薄肉部３４が破断するように構成されている（図５Ａ参照）。つまり、封口体１７は、弁部３０の反転を利用して薄肉部３４が破断するように設計されているため、薄肉部３４の破断により弁部３０が環状部３１から完全に切り離される。詳しくは後述するが、封口体１７は、反転圧Ｒ、第１ベント圧Ｖ１、及び第２ベント圧Ｖ２が、Ｖ２≦Ｒ＜Ｖ１の関係を満たすように構成されている。 The valve portion 30 has a convex shape (downward convex shape) inside the battery case 15, and when the internal pressure of the battery case 15 reaches a predetermined reversal pressure R, the valve portion 30 has a convex shape (upward convex shape) outside the case. Invert to be. The thin portion 34 is configured to break at the same time as the valve portion 30 is inverted (see FIG. 5A). That is, since the sealing body 17 is designed so that the thin-walled portion 34 is broken by utilizing the inversion of the valve portion 30, the valve portion 30 is completely separated from the annular portion 31 by the breaking of the thin-walled portion 34. As will be described in detail later, the sealing body 17 is configured such that the reversing pressure R, the first vent pressure V1 and the second vent pressure V2 satisfy the relationship of V2 ≦ R <V1.

封口体１７を備えた密閉電池１０によれば、電池に異常が発生して電池ケース１５の内圧が上昇したときに、弁部３０が反転して環状部３１から完全に切り離されることで、封口体１７に大きなガスの排出経路が形成されると共に、正極リード２０と外部リード３６の電流経路が遮断される。 According to the sealed battery 10 provided with the sealing body 17, when an abnormality occurs in the battery and the internal pressure of the battery case 15 rises, the valve portion 30 is inverted and completely separated from the annular portion 31 to seal the sealing body. A large gas discharge path is formed in the body 17, and the current paths of the positive electrode lead 20 and the external lead 36 are cut off.

封口体１７は、例えば、薄肉部３４によって区分けされた弁部３０及び環状部３１を含む１枚の金属板によって構成される。本実施形態では、弁部３０及び環状部３１を有する金属板が封口体１７の天板を構成している。この場合、弁部３０には外部装置（図示せず）に接続される外部リード３６が溶接等で接続され、環状部３１には電極体１４の正極１１に接続される正極リード２０が溶接等で接続される。外部リード３６と弁部３０、正極リード２０と環状部３１がそれぞれ電気的に接続されることで、弁部３０が環状部３１から完全に切り離されたときに、正極リード２０と外部リード３６の電流経路が遮断される。正極リード２０と外部リード３６の間に電流遮断機構を設ける場合、金属板が封口体１７の天板を構成することが好ましい。 The sealing body 17 is composed of, for example, one metal plate including a valve portion 30 and an annular portion 31 separated by a thin-walled portion 34. In the present embodiment, the metal plate having the valve portion 30 and the annular portion 31 constitutes the top plate of the sealing body 17. In this case, an external lead 36 connected to an external device (not shown) is connected to the valve portion 30 by welding or the like, and a positive electrode lead 20 connected to the positive electrode 11 of the electrode body 14 is welded or the like to the annular portion 31. Connected with. By electrically connecting the external lead 36 and the valve portion 30, and the positive electrode lead 20 and the annular portion 31, respectively, when the valve portion 30 is completely separated from the annular portion 31, the positive electrode lead 20 and the external lead 36 The current path is cut off. When a current cutoff mechanism is provided between the positive electrode lead 20 and the external lead 36, it is preferable that the metal plate constitutes the top plate of the sealing body 17.

なお、密閉電池１０は、環状部３１に負極リード２１が接続される構造であってもよい。この場合、封口体１７が負極外部端子となる。また、封口体１７は、本開示の目的を損なわない範囲で、複数の部材から構成されていてもよい。但し、より効果的に封口体１７の厚みを低減し、製造コストを削減するためには、封口体１７は１枚の金属板で構成されることが好ましい。 The sealed battery 10 may have a structure in which the negative electrode lead 21 is connected to the annular portion 31. In this case, the sealing body 17 becomes the negative electrode external terminal. Further, the sealing body 17 may be composed of a plurality of members as long as the object of the present disclosure is not impaired. However, in order to more effectively reduce the thickness of the sealing body 17 and reduce the manufacturing cost, it is preferable that the sealing body 17 is composed of one metal plate.

封口体１７は、例えば１枚の金属板を用いて、当該金属板に環状の薄肉部３４を形成し、電池ケース１５の内側に凸となるようにプレス加工することで製造される。好適な金属板の一例は、アルミニウムを主成分とするアルミニウム合金板である。金属板の厚みは特に限定されないが、一例としては、薄肉部３４以外の部分で０．３ｍｍ～２ｍｍである。薄肉部３４の厚みは、例えば弁部３０の厚みの１０％～５０％である。弁部３０と環状部３１の厚みは、同じであってもよく、異なっていてもよい。 The sealing body 17 is manufactured by forming an annular thin-walled portion 34 on the metal plate, for example, using one metal plate, and pressing the metal plate so as to be convex inward. An example of a suitable metal plate is an aluminum alloy plate containing aluminum as a main component. The thickness of the metal plate is not particularly limited, but as an example, it is 0.3 mm to 2 mm in a portion other than the thin portion 34. The thickness of the thin portion 34 is, for example, 10% to 50% of the thickness of the valve portion 30. The thickness of the valve portion 30 and the annular portion 31 may be the same or different.

薄肉部３４には、環状の溝３５が形成される。薄肉部３４の厚みは、溝３５の深さを変更することで調整できる。溝３５（薄肉部３４）の幅は小さく、細線状に形成される。溝３５は、封口体１７の外面に形成されてもよいが、好ましくは封口体１７の内面に形成される。図３に例示するように、溝３５（薄肉部３４）は、角のない円形状に形成されることが好ましく、略真円状に形成されることが特に好ましい。ここで、「略真円状」とは、真円形状及び実質的に真円と認められる形状を意味する。なお、薄肉部３４の形状は溝状に限定されず、易破断部として作用できる程度に薄肉部３４の厚みが設定されていればよい。例えば、弁部３０から薄肉部３４にかけて金属板の厚みが連続的に減少するように薄肉部３４の厚みを設定することができる。 An annular groove 35 is formed in the thin portion 34. The thickness of the thin portion 34 can be adjusted by changing the depth of the groove 35. The width of the groove 35 (thin wall portion 34) is small and is formed in a fine line shape. The groove 35 may be formed on the outer surface of the sealing body 17, but is preferably formed on the inner surface of the sealing body 17. As illustrated in FIG. 3, the groove 35 (thin-walled portion 34) is preferably formed in a circular shape without corners, and particularly preferably formed in a substantially perfect circular shape. Here, the "substantially perfect circle" means a perfect circle shape and a shape recognized as a substantially perfect circle. The shape of the thin-walled portion 34 is not limited to the groove shape, and the thickness of the thin-walled portion 34 may be set to such an extent that it can act as an easily broken portion. For example, the thickness of the thin-walled portion 34 can be set so that the thickness of the metal plate continuously decreases from the valve portion 30 to the thin-walled portion 34.

弁部３０及び環状部３１は、上述の通り、薄肉部３４（溝３５）によって区切られるため、弁部３０及び環状部３１の平面視形状は薄肉部３４の平面視形状によって決定される。薄肉部３４に囲まれた部分である弁部３０は、平面視略真円形状を有することが好ましい。この場合、薄肉部３４を全長にわたって完全に破断させることが容易になる。弁部３０の外側に存在する環状部３１は、略一定の内径及び外径を有する平面視円環状に形成されることが好ましい。弁部３０と環状部３１の面積比は特に限定されず、弁部３０の面積は環状部３１の面積より大きくてもよく、小さくてもよい。 Since the valve portion 30 and the annular portion 31 are separated by the thin wall portion 34 (groove 35) as described above, the plan view shape of the valve portion 30 and the annular portion 31 is determined by the plan view shape of the thin wall portion 34. The valve portion 30, which is a portion surrounded by the thin-walled portion 34, preferably has a substantially perfect circular shape in a plan view. In this case, it becomes easy to completely break the thin portion 34 over the entire length. The annular portion 31 existing on the outside of the valve portion 30 is preferably formed into a planar annular portion having a substantially constant inner diameter and outer diameter. The area ratio between the valve portion 30 and the annular portion 31 is not particularly limited, and the area of the valve portion 30 may be larger or smaller than the area of the annular portion 31.

弁部３０は、電池ケース１５の内圧が反転圧Ｒより低い通常の使用状態において、電池ケース１５の内側に凸の下凸形状を有する。即ち、弁部３０は、電池ケース１５の外側から見ると、電池ケース１５の内側に凹んでいる。弁部３０は、電極体１４と接触しない範囲で、電極体１４側に膨出していることが好ましい。また、弁部３０は、電池ケース１５の内圧が反転圧Ｒに達したときに、電池ケース１５の外側に凸の上凸形状となるように反転する。即ち、弁部３０は、下凸形状から上凸形状に変形可能な構造を有する。 The valve portion 30 has a convex downward convex shape inside the battery case 15 in a normal use state where the internal pressure of the battery case 15 is lower than the reversal pressure R. That is, the valve portion 30 is recessed inside the battery case 15 when viewed from the outside of the battery case 15. The valve portion 30 preferably bulges toward the electrode body 14 so as not to come into contact with the electrode body 14. Further, when the internal pressure of the battery case 15 reaches the reversing pressure R, the valve portion 30 is inverted so as to have a convex upward convex shape on the outside of the battery case 15. That is, the valve portion 30 has a structure that can be deformed from a downward convex shape to an upward convex shape.

図２に例示するように、封口体１７は、下凸形状から上凸形状に反転する部分である反転部Ｚ１と、反転しない非反転部Ｚ２との境界位置に、薄肉部３４が形成された構造を有していてもよい。図２に示す形態では、電極体１４側に膨出する下凸形状が形成された部分の全体が反転部Ｚ１であり、下凸形状部の上端に沿って薄肉部３４が形成されている。また、図４に例示するように、封口体１７は、弁部３０の範囲を超えて、即ち薄肉部３４の外側に位置する環状部３１にわたって、反転部Ｚ１（下凸形状部）が形成された構造を有していてもよい。この場合、弁部３０と共に、環状部３１の一部も上凸形状に反転する。 As illustrated in FIG. 2, in the sealing body 17, a thin-walled portion 34 is formed at a boundary position between an inverted portion Z1 which is a portion inverted from a downward convex shape to an upward convex shape and a non-inverted portion Z2 which is not inverted. It may have a structure. In the form shown in FIG. 2, the entire portion where the downwardly convex shape that bulges toward the electrode body 14 side is formed is the inverted portion Z1, and the thin-walled portion 34 is formed along the upper end of the downwardly convex shape portion. Further, as illustrated in FIG. 4, in the sealing body 17, an inverted portion Z1 (downward convex shape portion) is formed beyond the range of the valve portion 30, that is, over the annular portion 31 located outside the thin-walled portion 34. It may have a structure. In this case, a part of the annular portion 31 is also inverted into an upward convex shape together with the valve portion 30.

弁部３０の形状は、電池ケース１５の内圧によって下凸形状から上凸形状に反転可能な形状であればよく、弁部３０の全体がドーム状に湾曲した形状であってもよい。好適な弁部３０の一例は、電極体１４側に最も膨出した平坦な底部３２と、底部３２の周囲に形成された環状の傾斜部３３とを有する。図２に示す例では、傾斜部３３は底部３２から環状部３１に向けて一定の勾配を有するように形成されており、底部３２と傾斜部３３の境界部に屈曲部が存在する。底部３２は、環状部３１と略平行に形成され、外装缶１６の底部と略平行に配置される。底部３２は、平面視略真円形状を有する。傾斜部３３は、底部３２を囲むように平面視円環状に形成され、かつ底部３２に近づくほど電極体１４に近接するテーパ状に形成されている。 The shape of the valve portion 30 may be any shape as long as it can be reversed from a downward convex shape to an upward convex shape by the internal pressure of the battery case 15, and the entire valve portion 30 may be curved in a dome shape. An example of a suitable valve portion 30 has a flat bottom portion 32 that bulges most toward the electrode body 14, and an annular inclined portion 33 formed around the bottom portion 32. In the example shown in FIG. 2, the inclined portion 33 is formed so as to have a constant gradient from the bottom portion 32 toward the annular portion 31, and a bent portion exists at the boundary portion between the bottom portion 32 and the inclined portion 33. The bottom portion 32 is formed substantially parallel to the annular portion 31 and is arranged substantially parallel to the bottom portion of the outer can 16. The bottom portion 32 has a substantially perfect circular shape in a plan view. The inclined portion 33 is formed in an annular shape in a plan view so as to surround the bottom portion 32, and is formed in a tapered shape closer to the electrode body 14 as it approaches the bottom portion 32.

封口体１７は、上述のように、弁部３０（反転部Ｚ１）の反転圧Ｒが、弁部３０の反転前の形状において薄肉部３４を破断させる第１ベント圧Ｖ１より小さく、弁部３０の反転後の形状において薄肉部３４を破断させる第２ベント圧Ｖ２以上となるように構成されている。封口体１７は、Ｒ＜Ｖ１となるように設計されているため、弁部３０の反転前における薄肉部３４の破断が抑制される。反転圧Ｒと第１ベント圧Ｖ１の差を大きくするほど、弁部３０の反転前における薄肉部３４の破断を防止し易くなる。 In the sealing body 17, as described above, the reversing pressure R of the valve portion 30 (reversing portion Z1) is smaller than the first vent pressure V1 that breaks the thin wall portion 34 in the shape of the valve portion 30 before reversing, and the valve portion 30. It is configured to have a second vent pressure V2 or more that breaks the thin-walled portion 34 in the shape after inversion. Since the sealing body 17 is designed so that R <V1, the breakage of the thin-walled portion 34 before the inversion of the valve portion 30 is suppressed. The larger the difference between the reversing pressure R and the first vent pressure V1, the easier it is to prevent the thin-walled portion 34 from breaking before the reversing of the valve portion 30.

また、封口体１７は、Ｖ２≦Ｒとなるように設計されているため、薄肉部３４は弁部３０の反転と同時に破断する。ここで、「反転と同時」とは、弁部３０が上凸形状に反転してから薄肉部３４の破断までの間に、薄肉部３４が弁部３０の反転を利用して破断できる程度に実質的にタイムラグが存在しないことを意味する。薄肉部３４が弁部３０の反転前に破断せず、反転と同時に破断する場合、即ち弁部３０の反転をトリガーとして薄肉部３４が破断する場合は、Ｖ２≦Ｒ＜Ｖ１の条件が満たされるものと推定される。 Further, since the sealing body 17 is designed so that V2 ≦ R, the thin-walled portion 34 breaks at the same time as the reversal of the valve portion 30. Here, "simultaneously with inversion" means that the thin-walled portion 34 can be broken by utilizing the inversion of the valve portion 30 between the time when the valve portion 30 is inverted into an upward convex shape and the time when the thin-walled portion 34 is broken. It means that there is virtually no time lag. When the thin-walled portion 34 does not break before the inversion of the valve portion 30 and breaks at the same time as the inversion, that is, when the thin-walled portion 34 breaks due to the inversion of the valve portion 30, the condition of V2 ≦ R <V1 is satisfied. It is presumed to be.

Ｖ２≦Ｒ＜Ｖ１の条件は、例えば弁部３０及び薄肉部３４の厚み、弁部３０の形状、封口体１７の構成材料などを制御することで実現できる。具体的には、弁部３０（反転部Ｚ１）の厚みを減少させると、弁部３０が反転し易くなり反転圧Ｒが下がる傾向にある。また、薄肉部３４の厚みを減少させると、ベント圧Ｖ１，Ｖ２はいずれも下がる傾向にある。電池ケース１５の内圧が上昇したときに、反転前の下凸形状の弁部３０から薄肉部３４には専ら剪断応力が作用し、反転後の上凸形状の弁部３０から薄肉部３４には剪断応力に加えて引張応力が作用する。このため、薄肉部３４の厚みをどのように変化させても、Ｖ２＜Ｖ１の条件が成立する。 The condition of V2 ≦ R <V1 can be realized by controlling, for example, the thickness of the valve portion 30 and the thin wall portion 34, the shape of the valve portion 30, the constituent material of the sealing body 17, and the like. Specifically, when the thickness of the valve portion 30 (reversing portion Z1) is reduced, the valve portion 30 tends to be inverted easily and the inversion pressure R tends to decrease. Further, when the thickness of the thin portion 34 is reduced, the vent pressures V1 and V2 tend to decrease. When the internal pressure of the battery case 15 rises, shear stress acts exclusively on the downwardly convex valve portion 30 to the thin-walled portion 34 before inversion, and the upwardly convex valve portion 30 to the thin-walled portion 34 after inversion acts exclusively on the thin-walled portion 34. Tensile stress acts in addition to shear stress. Therefore, no matter how the thickness of the thin portion 34 is changed, the condition of V2 <V1 is satisfied.

第２ベント圧Ｖ２は、反転圧Ｒと同程度であってもよいが、反転圧Ｒより低いことが好ましい（Ｖ２＜Ｒ）。この場合、弁部３０の反転を利用して薄肉部３４を破断させることが容易になる。なお、薄肉部３４の形成位置は第２ベント圧Ｖ２に影響する。特に、反転部Ｚ１と非反転部Ｚ２の境界位置の近傍に薄肉部３４を形成すると、薄肉部３４の破断への引張応力の寄与が大きくなる。 The second vent pressure V2 may be about the same as the reversal pressure R, but is preferably lower than the reversal pressure R (V2 <R). In this case, it becomes easy to break the thin-walled portion 34 by utilizing the inversion of the valve portion 30. The formation position of the thin portion 34 affects the second vent pressure V2. In particular, when the thin-walled portion 34 is formed in the vicinity of the boundary position between the inverted portion Z1 and the non-reversed portion Z2, the contribution of the tensile stress to the fracture of the thin-walled portion 34 becomes large.

図２及び図３に示すように、薄肉部３４は、反転部Ｚ１、又は反転部Ｚ１と非反転部Ｚ２の境界位置に形成される。図２に示す形態では下凸形状の上端に沿って薄肉部３４が形成され、図４に示す例では下凸形状の上端から離れた傾斜部に薄肉部３４が形成されている。反転部Ｚ１を電極体１４側に大きく膨出させることで反転圧Ｒが大きくなる。その場合、反転後の反転部Ｚ１は電極体１４とは反対側に大きく膨出するため、薄肉部３４に作用する引張応力が大きくなって第２ベント圧Ｖ２が下がる傾向にある。 As shown in FIGS. 2 and 3, the thin-walled portion 34 is formed at the boundary position between the inverted portion Z1 or the inverted portion Z1 and the non-inverted portion Z2. In the form shown in FIG. 2, the thin-walled portion 34 is formed along the upper end of the downward-convex shape, and in the example shown in FIG. 4, the thin-walled portion 34 is formed in the inclined portion away from the upper end of the downward-convex shape. By greatly expanding the reversing portion Z1 toward the electrode body 14, the reversing pressure R becomes large. In that case, since the inverted portion Z1 after inversion greatly swells on the side opposite to the electrode body 14, the tensile stress acting on the thin-walled portion 34 tends to increase and the second vent pressure V2 tends to decrease.

図５Ａは、上記構成を備えた封口体１７の弁部３０が反転・ベント（開弁）する様子を示す図である。比較として、従来技術の一例である封口体１００が反転・ベントする様子を図５Ｂに示す。 FIG. 5A is a diagram showing how the valve portion 30 of the sealing body 17 having the above configuration reverses and vents (opens). For comparison, FIG. 5B shows how the sealing body 100, which is an example of the prior art, is inverted and vented.

図５Ｂに例示する従来の封口体１００は、下弁体１０１、上弁体１０２、及び下弁体１０１と上弁体１０２の間に介在する絶縁部材１０３を有する。下弁体１０１と上弁体１０２は各々の中央部で互いに接続され、各々の周縁部の間に絶縁部材１０３が配置されている。この場合、電池に異常が発生して電池ケースの内圧が上昇すると、下弁体１０１の薄肉部１０４が破断して上弁体１０２が上方に押し上げられ、上弁体１０２が下凸形状から上凸形状に反転する。これにより、正極リード２０と外部リード３６の電流経路が遮断される。さらに内圧が上昇すると、上弁体１０２の薄肉部１０５が破断し、ガスの排出経路が形成される。 The conventional sealing body 100 exemplified in FIG. 5B has a lower valve body 101, an upper valve body 102, and an insulating member 103 interposed between the lower valve body 101 and the upper valve body 102. The lower valve body 101 and the upper valve body 102 are connected to each other at the central portion thereof, and the insulating member 103 is arranged between the peripheral portions thereof. In this case, when an abnormality occurs in the battery and the internal pressure of the battery case rises, the thin portion 104 of the lower valve body 101 breaks and the upper valve body 102 is pushed upward, and the upper valve body 102 moves upward from the downward convex shape. Invert to a convex shape. As a result, the current paths of the positive electrode lead 20 and the external lead 36 are cut off. When the internal pressure further rises, the thin portion 105 of the upper valve body 102 breaks and a gas discharge path is formed.

従来の封口体１００では、上記の通り、上弁体１０２の反転から薄肉部１０５の破断までの間にタイムラグが存在するため、薄肉部１０５の破断の際に上弁体の１０２の反転を利用することができない。そのため、薄肉部１０５を全長にわたって破断させて大きなガスの排出経路を確保することが困難である。また、正極リード２０と外部リード３６の電流経路を遮断するために、下弁体１０１、上弁体１０２、及び絶縁部材１０３の３つの部品が必要であり、封口体１００の構造が複雑になってしまう。 In the conventional sealing body 100, as described above, since there is a time lag between the inversion of the upper valve body 102 and the breakage of the thin-walled portion 105, the inversion of the upper valve body 102 is used when the thin-walled portion 105 is broken. Can not do it. Therefore, it is difficult to break the thin portion 105 over the entire length to secure a large gas discharge path. Further, in order to cut off the current paths of the positive electrode lead 20 and the external lead 36, three parts of the lower valve body 101, the upper valve body 102, and the insulating member 103 are required, and the structure of the sealing body 100 becomes complicated. It ends up.

これに対し、図５Ａに例示する封口体１７では、弁部３０（反転部Ｚ１）が下凸形状から上凸形状に反転すると同時に、薄肉部３４が破断し弁部３０が環状部３１から完全に切り離される（図５Ａ（ｂ）参照）。これにより、従来の封口体１００に比べて大きなガスの排出経路が形成されると共に正極リード２０と外部リード３６の電流経路が遮断される。封口体１７は、上述のＶ２≦Ｒ＜Ｖ１の条件を満たすように構成されているため、弁部３０の反転を利用して薄肉部３４を全長にわたって破断させることができる。このように、弁部３０が環状部３１から完全に切り離されるため、１枚の金属板で正極リード２０と外部リード３６の電流経路を遮断することができる。そのため、封口体１７を備えた密閉電池１０によれば部品点数の削減による封口体１７の構造の単純化が可能となる。 On the other hand, in the sealing body 17 illustrated in FIG. 5A, the valve portion 30 (reversing portion Z1) is inverted from the downward convex shape to the upward convex shape, and at the same time, the thin wall portion 34 is broken and the valve portion 30 is completely removed from the annular portion 31. (See FIG. 5A (b)). As a result, a gas discharge path larger than that of the conventional sealing body 100 is formed, and the current paths of the positive electrode lead 20 and the external lead 36 are cut off. Since the sealing body 17 is configured to satisfy the above-mentioned condition of V2 ≦ R <V1, the thin-walled portion 34 can be broken over the entire length by utilizing the inversion of the valve portion 30. In this way, since the valve portion 30 is completely separated from the annular portion 31, the current path of the positive electrode lead 20 and the external lead 36 can be cut off by one metal plate. Therefore, according to the sealed battery 10 provided with the sealing body 17, the structure of the sealing body 17 can be simplified by reducing the number of parts.

１０ 密閉電池、１１ 正極、１２ 負極、１３ セパレータ、１４ 電極体、１５ 電池ケース、１６ 外装缶、１７ 封口体、１８，１９ 絶縁板、２０ 正極リード、２１ 負極リード、２２ 溝入部、２３ ガスケット、３０ 弁部、３１ 環状部、３２ 底部、３３ 傾斜部、３４ 薄肉部、３５ 溝、３６ 外部リード、Ｚ１ 反転部、Ｚ２ 非反転部 10 Sealed battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 15 Battery case, 16 Exterior can, 17 Seal body, 18, 19 Insulation plate, 20 Positive electrode lead, 21 Negative electrode lead, 22 Grooved part, 23 Gasket, 30 Valve part, 31 annular part, 32 bottom part, 33 inclined part, 34 thin wall part, 35 groove, 36 external lead, Z1 reversing part, Z2 non-reversing part

Claims (4)

有底筒状の外装缶、及び前記外装缶の開口部を塞ぐ封口体を含む電池ケースと、
前記電池ケース内に収容された電極体と、
を備える密閉電池であって、
前記封口体は金属板を含み、
前記金属板は、
環状に形成された薄肉部と、
前記電池ケースの内側に凸の形状を有し、前記電池ケースの内圧が所定の反転圧Ｒに達したときに当該ケースの外側に凸となるように反転する、前記薄肉部に囲まれた弁部と、
前記薄肉部の外側に位置する環状部と、
を有し、
前記封口体は、前記弁部の反転と同時に前記薄肉部が破断するように構成されている、密閉電池。 A battery case including a bottomed cylindrical outer can and a sealing body that closes the opening of the outer can.
The electrode body housed in the battery case and
It is a sealed battery equipped with
The sealing body includes a metal plate and contains a metal plate.
The metal plate is
The thin-walled part formed in a ring shape and
A valve surrounded by a thin portion that has a convex shape on the inside of the battery case and reverses so as to be convex on the outside of the case when the internal pressure of the battery case reaches a predetermined reversal pressure R. Department and
An annular portion located outside the thin-walled portion and
Have,
The sealing body is a closed battery configured so that the thin-walled portion breaks at the same time as the valve portion is inverted. 前記封口体は、前記反転圧Ｒが、前記弁部の反転前の形状において前記薄肉部を破断させる第１ベント圧Ｖ１より小さく（Ｒ＜Ｖ１）、前記弁部の反転後の形状において前記薄肉部を破断させる第２ベント圧Ｖ２以上（Ｖ２≦Ｒ）となるように構成されている、請求項１に記載の密閉電池。 In the sealing body, the reversal pressure R is smaller than the first vent pressure V1 (R <V1) that breaks the thin wall portion in the shape before the reversal of the valve portion, and the thin wall portion is formed in the shape after the reversal of the valve portion. The sealed battery according to claim 1, wherein the second vent pressure V2 or more (V2 ≦ R) for breaking the portion is configured. 前記金属板は、前記封口体の天板を構成し、
前記弁部には、外部装置に接続される外部リードが接続され、
前記環状部には、前記電極体の正極又は負極に接続される電極リードが接続される、請求項１又は２に記載の密閉電池。 The metal plate constitutes the top plate of the sealing body, and the metal plate constitutes the top plate of the sealing body.
An external lead connected to an external device is connected to the valve portion.
The sealed battery according to claim 1 or 2, wherein an electrode lead connected to a positive electrode or a negative electrode of the electrode body is connected to the annular portion. 前記弁部は、前記電極体側に最も膨出した平坦な底部と、前記底部の周囲に形成された環状の傾斜部とを有する、請求項１～３のいずれか１項に記載の密閉電池。 The sealed battery according to any one of claims 1 to 3, wherein the valve portion has a flat bottom portion that bulges most toward the electrode body side and an annular inclined portion formed around the bottom portion.
JP2018235408A 2018-12-17 2018-12-17 Sealed battery Pending JP2022031997A (en)

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