JP2020004650A

JP2020004650A - Secondary battery

Info

Publication number: JP2020004650A
Application number: JP2018124787A
Authority: JP
Inventors: 前園　寛志; Hiroshi Maezono; 寛志前園
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 2018-06-29
Filing date: 2018-06-29
Publication date: 2020-01-09
Anticipated expiration: 2038-06-29
Also published as: JP7110010B2

Abstract

To provide a secondary battery in which a current interruption mechanism is stably operated even in any batteries by reducing variations of an operation pressure of the current interruption mechanism.SOLUTION: A secondary battery of the invention comprises: a battery case having an opening; an electrode body containing a positive electrode and a negative electrode; a collector electrically connected to the positive electrode and the negative electrode; a sealing board sealing the opening; an outer terminal attached to the sealing board; a conductive member electrically connected to an outer terminal between the sealing board and the electrode body, and having an opening part on the electrode body side; and a deformation board 40 connected to the collector by sealing the opening part and deformed when a pressure in the battery case becomes a prescribed value. The deformation board has: a first groove 71 which has an almost rectangular shape, a pair of long sides 61 and 62 and a pair of short sides, and which is arranged on one long side from the connection part of the deformation board and the collector while being actually in parallel to the long sides; and a second groove 72 which is arranged at the other long side from the connection part of the deformation board and the collector while being actually in parallel to the long side.SELECTED DRAWING: Figure 9

Description

本発明は、二次電池に関するものである。 The present invention relates to a secondary battery.

電気自動車（ＥＶ）やハイブリッド電気自動車（ＨＥＶ、ＰＨＥＶ）の駆動用電源、太陽光発電、風力発電等の出力変動を抑制するための用途や夜間に電力をためて昼間に利用するための系統電力のピークシフト用途等の定置用蓄電池システム等において、アルカリ二次電池や非水電解質二次電池が使用されている。 Power supply for driving electric vehicles (EVs) and hybrid electric vehicles (HEVs and PHEVs), applications for suppressing output fluctuations such as solar power generation and wind power generation, and system power for storing power at night and using it during the day Alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used in stationary storage battery systems for peak shift applications.

このような用途に使用される電池では、例えば下記特許文献１に示されているように、電池外装体内の圧力が高まったときに内圧を開放するガス排出弁を設けるだけでなく、外部端子と外装体内部の電極体との間の電気的接続を遮断する電流遮断機構が設けられている。 In a battery used for such an application, for example, as shown in Patent Literature 1 below, not only is a gas exhaust valve that releases internal pressure when the pressure inside the battery outer casing rises, but also an external terminal and A current interrupting mechanism is provided for interrupting the electrical connection with the electrode body inside the exterior body.

特開２０１８−４１６７８号公報JP 2018-41678 A

電流遮断機構においては、例えば特許文献１に開示された技術のように、変形板に溶接された集電体に溝状のノッチ部を設ける構造が採用されている。そしてこの構造では、電池ケース内圧力が高まって変形板が変形するとノッチ部が破断して外部端子と電極体との間の電気的接続を遮断する。 The current interrupting mechanism adopts a structure in which a current collector welded to a deformed plate is provided with a groove-shaped notch, as in the technique disclosed in Patent Document 1, for example. In this structure, when the pressure inside the battery case increases and the deformed plate is deformed, the notch portion breaks and cuts off the electrical connection between the external terminal and the electrode body.

電流遮断機構は上述のように作動するが、重要なのは多数の電池を作製する際にいずれの電池においても電池ケース内において決められた圧力値になったときに電流遮断機構が安定的に作動することである。 The current cutoff mechanism operates as described above, but what is important is that when producing a large number of batteries, the current cutoff mechanism operates stably when a predetermined pressure value is obtained in the battery case in any of the batteries. That is.

電池の組み立て工程において部品に衝撃荷重がかかったり、部品の成形時に微小な亀裂が入ったり、部品形状にバラツキが生じたりする等に起因する作動圧力のバラツキは回避が非常に困難である。しかしながら、このような組み立て工程や部品作成工程に起因するバラツキ要素が存在していても、これらの要素に左右されず、むしろその影響を打ち消して電流遮断機構の作動圧のバラツキを小さくするための検討を行ったところ、変形板の形状を工夫することにより電流遮断機構の作動圧のバラツキを小さくできることを本願発明者は見出した。 It is very difficult to avoid a variation in operating pressure due to an impact load applied to a part in a battery assembling process, a minute crack during molding of the part, a variation in the part shape, and the like. However, even if there are variation elements caused by such an assembling process or a component creation process, the variation factors of the operating pressure of the current interrupting mechanism are reduced without being influenced by these factors. As a result of the study, the inventor of the present application has found that variations in the operating pressure of the current interrupting mechanism can be reduced by devising the shape of the deformed plate.

本発明はかかる点に鑑みてなされたものであり、その目的とするところは、電流遮断機構の作動圧のバラツキを小さくしていずれの電池においても電流遮断機構が安定的に作動する二次電池を提供することにある。 The present invention has been made in view of such a point, and an object of the present invention is to reduce the variation in the operating pressure of the current cutoff mechanism and to make the current cutoff mechanism operate stably in any battery. Is to provide.

本発明の第１の二次電池は、開口を有する電池ケースと、前記電池ケースに収納された、正極および負極を含む電極体と、前記正極又は負極に電気的に接続された集電体と、前記電池ケースの前記開口を封口する封口板と、前記封口板に取り付けられた外部端子と、前記封口板と前記電極体との間に位置し、前記外部端子に電気的に接続され、前記電極体側に開口部分を有する導電部材と、前記開口部分を密閉し、前記集電体に接続され、前記電池ケース内の圧力が所定値となったときに変形する変形板とを備え、前記変形板は略矩形形状を有していて、一対の長辺と一対の短辺を有しているとともに、前記長辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも一方の前記長辺側に配置される第１溝と、前記長辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも他方の前記長辺側に配置される第２溝とを有する構成を有している。略矩形形状とは、矩形そのものを含み、矩形の角部分がＲを有して（長辺と短辺との交差部分が曲線で構成されて）いるものも含む概念である。実質的に平行とは、２つの辺のなす角が１０°以下であることであり、好ましくは５°以下である。 A first secondary battery of the present invention includes a battery case having an opening, an electrode body containing a positive electrode and a negative electrode housed in the battery case, and a current collector electrically connected to the positive electrode or the negative electrode. A sealing plate for sealing the opening of the battery case, an external terminal attached to the sealing plate, located between the sealing plate and the electrode body, electrically connected to the external terminal, A conductive member having an opening on the electrode body side; and a deformable plate that seals the opening, is connected to the current collector, and deforms when a pressure in the battery case reaches a predetermined value. The plate has a substantially rectangular shape, has a pair of long sides and a pair of short sides, and is substantially parallel to the long side and the deformable plate and the current collector A first groove disposed on one of the long sides with respect to the connecting portion; It has a configuration and a second groove disposed on the other of the long sides of the connection portion between the A and and the deformable plate substantially parallel the current collector for. The substantially rectangular shape is a concept including a rectangle itself and a rectangle having a corner portion having an R (an intersection between a long side and a short side is formed by a curve). Substantially parallel means that the angle between the two sides is 10 ° or less, and preferably 5 ° or less.

前記変形板は、前記短辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも一方の前記短辺側に配置される第３溝と、前記短辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも他方の前記短辺側に配置される第４溝とを有している構成であってもよい。 A third groove that is substantially parallel to the short side and that is disposed on one of the short sides relative to a connection portion between the deformable plate and the current collector; A fourth groove that is substantially parallel to the side and has a fourth groove disposed on the other short side of the connection portion between the deformable plate and the current collector. Good.

前記一方の前記長辺と前記第１溝との間の距離及び前記他方の前記長辺と前記第２溝との間の距離は、前記一方の前記短辺と前記第３溝との間の距離及び前記他方の前記短辺と前記第４溝との間の距離よりも小さい構成であってもよい。 The distance between the one long side and the first groove and the distance between the other long side and the second groove are between the one short side and the third groove. The distance may be smaller than the distance between the other short side and the fourth groove.

前記第１溝は前記第３溝及び前記第４溝と連結されており、前記第２溝は前記第３溝及び前記第４溝と連結されている構成であってもよい。 The first groove may be connected to the third groove and the fourth groove, and the second groove may be connected to the third groove and the fourth groove.

前記変形板は平面視においてＵ字形状のＵ字溝をさらに有しており、前記Ｕ字溝を構成する実質的に平行な一対の直線状の溝は、前記一対の前記長辺間の中心線を挟んで前記長辺に沿って延びており、前記Ｕ字溝の前記一対の直線状の溝を結ぶ部分は前記一対の直線状の溝よりも前記変形板の周縁側に位置している構成であってもよい。 The deforming plate further has a U-shaped groove having a U-shape in a plan view, and a pair of substantially parallel linear grooves constituting the U-shaped groove has a center between the pair of long sides. A portion of the U-shaped groove connecting the pair of linear grooves is located closer to the periphery of the deformable plate than the pair of linear grooves. It may be a configuration.

本発明の第２の二次電池は、開口を有する電池ケースと、前記電池ケースに収納された、正極および負極を含む電極体と、前記正極又は負極に電気的に接続された集電体と、前記電池ケースの前記開口を封口する封口板と、前記封口板に取り付けられた外部端子と、前記封口板と前記電極体との間に位置し、前記外部端子に電気的に接続され、前記電極体側に開口部分を有する導電部材と、前記開口部分を密閉し、前記集電体に接続され、前記電池ケース内の圧力が所定値となったときに変形する変形板とを備え、前記変形板は略矩形形状を有していて、略矩形形状の中央部分において前記集電体と接続されているとともに、平面視においてＵ字形状のＵ字溝を有しており、前記Ｕ字溝を構成する実質的に平行な一対の直線状の溝は、略矩形形状の２つの長辺間の中心線を挟んで前記長辺に沿って延びており、前記Ｕ字溝の前記一対の直線状の溝を結ぶ部分は前記一対の直線状の溝よりも前記変形板の周縁側に位置している構成を有している。 A second secondary battery of the present invention includes a battery case having an opening, an electrode body containing a positive electrode and a negative electrode, which is housed in the battery case, and a current collector electrically connected to the positive electrode or the negative electrode. A sealing plate that seals the opening of the battery case, an external terminal attached to the sealing plate, located between the sealing plate and the electrode body, electrically connected to the external terminal, A conductive member having an opening on the electrode body side; and a deformable plate that seals the opening, is connected to the current collector, and deforms when a pressure in the battery case reaches a predetermined value. The plate has a substantially rectangular shape, is connected to the current collector at a central portion of the substantially rectangular shape, and has a U-shaped groove having a U-shape in plan view. A pair of substantially parallel linear grooves that constitutes a substantially rectangular shape. A portion extending between the pair of linear grooves of the U-shaped groove, the portion extending along the long side with a center line between two long sides of the U-shaped groove being more deformed than the pair of linear grooves. It has a configuration located on the peripheral side of the plate.

本発明の二次電池は、変形板に長辺に沿った溝が設けられているので変形板が変形しやすくなって、電流遮断機構を安定して作動させることができる。 In the secondary battery of the present invention, since the groove along the long side is provided in the deformable plate, the deformable plate is easily deformed, and the current cutoff mechanism can be operated stably.

実施形態に係る電池の電池ケース正面部分と絶縁シート正面部分とを取り除いた電池内部を示す模式的な正面図である。FIG. 2 is a schematic front view showing the inside of the battery according to the embodiment with the battery case front portion and the insulating sheet front portion removed. 実施形態に係る電池の模式的な上面図である。1 is a schematic top view of a battery according to an embodiment. 実施形態に係る電池の電池ケース側面（正極側）部分と絶縁シート側面（正極側）部分とを取り除いた正極側の電池内部を示す模式的な側面図である。FIG. 2 is a schematic side view showing the inside of the battery on the positive electrode side, with the battery case side surface (positive electrode side) and the insulating sheet side surface (positive electrode side) removed from the battery according to the embodiment. 実施形態に係る電池の電池ケース側面（負極側）部分と絶縁シート側面（負極側）部分とを取り除いた負極側の電池内部を示す模式的な側面図である。FIG. 2 is a schematic side view showing the inside of the battery on the negative electrode side with the side of the battery case (negative electrode side) and the side of the insulating sheet (negative electrode side) removed from the battery according to the embodiment. 実施形態に係る電池を、正面と平行に上面の中心線に沿って切断した、正極端子近傍の模式的な拡大断面図である。FIG. 2 is a schematic enlarged cross-sectional view of the vicinity of a positive electrode terminal, which is cut along a center line of an upper surface of the battery according to the embodiment in parallel with a front surface. 実施形態に係る電池を、側面と平行に正極端子の中心線に沿って切断した、正極端子近傍の模式的な拡大断面図である。FIG. 4 is a schematic enlarged cross-sectional view of the vicinity of the positive electrode terminal, which is cut along the center line of the positive electrode terminal in parallel with the side surface of the battery according to the embodiment. 変形板の下面側の模式的な図である（溝は不図示）。It is a schematic diagram of the lower surface side of a deformation plate (a groove is not shown). 図７のＡの部分の応力分布を示す模式的な図である。FIG. 8 is a schematic diagram illustrating a stress distribution of a portion A in FIG. 7. 実施形態に係る変形板に形成された溝を示す模式的な図である。It is a schematic diagram which shows the groove formed in the deformation plate concerning embodiment. 図７のＣの部分の応力分布を示す模式的な図である。FIG. 8 is a schematic diagram illustrating a stress distribution of a portion C in FIG. 7. 他の実施形態に係る変形板に形成された溝を示す模式的な図である。It is a schematic diagram showing a groove formed in a deformed plate according to another embodiment. 図７のＢの部分の応力分布を示す模式的な図である。FIG. 8 is a schematic diagram illustrating a stress distribution of a portion B in FIG. 7. 別の実施形態に係る変形板に形成された溝を示す模式的な図である。It is a schematic diagram showing a groove formed in a deformed plate according to another embodiment. 変形板の上面側の模式的な図である（溝は不図示）。It is a schematic diagram of the upper surface side of a deformation plate (a groove | channel is not shown). 図１４のＤの部分の応力分布を示す模式的な図である。FIG. 15 is a schematic diagram illustrating a stress distribution in a portion D in FIG. 14. さらに別の実施形態に係る変形板に形成された溝を示す模式的な図である。It is a schematic diagram showing a groove formed in a deformed plate according to still another embodiment.

本発明の実施形態について具体的に説明を行う前に、本発明者が本発明に想到した経緯を簡単に説明する。 Before the embodiment of the present invention is specifically described, the background that the present inventor came to the present invention will be briefly described.

発明が解決しようとする課題の欄で説明したように、電流遮断機構において電池の組み立て工程や部品作成工程に起因する作動圧力のバラツキ要素が存在している場合、ノッチ部（薄肉部）の厚み（残肉厚み）を大きくすると相対的にはバラツキ要素の影響度合を減少させることができるので、ノッチ部の厚みを大きくすることが好ましいと考えられる。しかしながら、破断する部分であるノッチ部の厚みを大きくするということは、電流遮断機構の作動圧力が大きくなってしまうことなので、単にノッチ部の厚みを大きくすることはできない。そこで、本発明者はノッチ部の厚みを大きくしても、電流遮断機構の作動圧力を大きくしないための工夫を様々に検討したところ、本発明を想到するにいたった。 As described in the section of the problem to be solved by the invention, when there is a variation element of the operating pressure due to the battery assembling process or the component making process in the current interrupting mechanism, the thickness of the notch (thin portion) Increasing the (remaining thickness) can relatively reduce the degree of influence of the variation element, so it is considered preferable to increase the thickness of the notch. However, increasing the thickness of the notch portion, which is the portion to be broken, increases the operating pressure of the current interrupting mechanism, and thus cannot simply increase the thickness of the notch portion. Therefore, the present inventor has made various studies to prevent the operating pressure of the current interrupting mechanism from being increased even if the thickness of the notch portion is increased, and came to the present invention.

以下、本発明の実施形態を図面に基づいて詳細に説明する。以下の好ましい実施形態の説明は、本質的に例示に過ぎず、本発明、その適用物或いはその用途を制限することを意図するものではない。以下の図面においては、説明の簡潔化のため、実質的に同一の機能を有する構成要素を同一の参照符号で示す。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description of the preferred embodiments below is merely exemplary in nature and is not intended to limit the invention, its applications, or its uses. In the drawings, components having substantially the same function are denoted by the same reference numeral for simplification of description.

（実施形態１）
最初に、実施形態１の二次電池を図１〜図４を用いて説明する。本実施形態の二次電池は、正極板と負極板とがセパレータ（何れも図示省略）を介して巻回された扁平状の電極体１１０を有している。正極を構成している正極板は、アルミニウム箔からなる正極芯体の両面に正極活物質合剤を塗布し、乾燥及び圧延した後、アルミニウム箔が一方の端部に長手方向に沿って帯状に露出するようにスリットすることにより作製される。また、負極を構成している負極板は、銅箔からなる負極芯体の両面に負極活物質合剤を塗布し、乾燥及び圧延した後、銅箔が一方の端部に長手方向に沿って帯状に露出するようにスリットすることによって作製される。 (Embodiment 1)
First, the secondary battery of Embodiment 1 will be described with reference to FIGS. The secondary battery of the present embodiment has a flat electrode body 110 in which a positive electrode plate and a negative electrode plate are wound via a separator (both not shown). The positive electrode plate constituting the positive electrode, the positive electrode active material mixture is applied to both surfaces of the positive electrode core body made of aluminum foil, dried and rolled, and then the aluminum foil is strip-shaped along one longitudinal direction at one end. It is manufactured by slitting to expose. In addition, the negative electrode plate constituting the negative electrode, the negative electrode active material mixture is applied to both surfaces of the negative electrode core body made of copper foil, dried and rolled, and then the copper foil is applied to one end along the longitudinal direction. It is manufactured by slitting so as to be exposed in a band shape.

そして、上述のようにして得られた正極板及び負極板を、正極板の正極芯体が露出した部分と負極板の負極芯体が露出した部分とがそれぞれ対向する電極と重ならない領域を有するようにずらして、ポリプロピレン及びポリエチレンからなる微多孔質セパレータを介して積層し巻回することで、電極体１１０が作製される。電極体１１０の巻回軸方向の一方の端部には正極芯体露出部１４１が形成され、他方の端部には負極芯体露出部１４０が形成される。 The positive electrode plate and the negative electrode plate obtained as described above have a region where the positive electrode core of the positive electrode plate is exposed and the portion of the negative electrode plate where the negative electrode core is exposed do not overlap with the electrodes facing each other. The electrode body 110 is manufactured by laminating and winding through a microporous separator made of polypropylene and polyethylene with such a shift. A positive electrode core exposed portion 141 is formed at one end of the electrode body 110 in the winding axis direction, and a negative electrode core exposed portion 140 is formed at the other end.

正極芯体露出部１４１は、正極集電体１０を介して外部端子である正極端子１３０に電気的に接続される。正極芯体露出部１４１の一方の外面には、正極集電体１０のリード部１４が溶接接続される。正極芯体露出部１４１の他方の外面には、正極集電体１０の受け部材１４３が溶接接続される。正極芯体露出部１４１の一方の外面と正極集電体１０のリード部１４との間には、開口を有する絶縁フィルムが配置され、絶縁フィルムの開口を通じて正極芯体露出部１４１と正極集電体１０のリード部１４とが溶接接続される。正極芯体露出部１４１の他方の外面と正極集電体１０の受け部材１４３との間には、開口を有する絶縁フィルム１４７が配置され、絶縁フィルム１４７の開口を通じて正極芯体露出部１４１と正極集電体１０の受け部材１４３とが溶接接続される。なお、正極集電体１０の受け部材１４３、絶縁フィルム１４７、及び正極芯体露出部１４１の一方の外面と正極集電体１０のリード部１４との間に配置された絶縁フィルムは必須の構成ではなく、省略することができる。 The positive electrode core exposed portion 141 is electrically connected to the positive terminal 130 serving as an external terminal via the positive electrode current collector 10. The lead portion 14 of the positive electrode current collector 10 is connected to one outer surface of the positive electrode core exposed portion 141 by welding. The receiving member 143 of the positive electrode current collector 10 is connected to the other outer surface of the positive electrode core exposed portion 141 by welding. An insulating film having an opening is disposed between one outer surface of the positive electrode core exposed portion 141 and the lead portion 14 of the positive electrode current collector 10, and the positive electrode core exposed portion 141 and the positive electrode current collector are formed through the opening of the insulating film. The lead portion 14 of the body 10 is connected by welding. An insulating film 147 having an opening is disposed between the other outer surface of the positive electrode core exposed portion 141 and the receiving member 143 of the positive electrode current collector 10, and the positive electrode core exposed portion 141 and the positive electrode are exposed through the opening of the insulating film 147. The receiving member 143 of the current collector 10 is connected by welding. The receiving member 143 of the positive electrode current collector 10, the insulating film 147, and the insulating film disposed between one outer surface of the positive electrode core exposed portion 141 and the lead portion 14 of the positive electrode current collector 10 are essential components. Instead, they can be omitted.

また、正極集電体１０は第１絶縁部材５０及び第２絶縁部材１５０によって封口板１２０と電気的に絶縁されている。 The positive electrode current collector 10 is electrically insulated from the sealing plate 120 by the first insulating member 50 and the second insulating member 150.

負極芯体露出部１４０は、負極集電体２０を介して外部端子である負極端子１３２に電気的に接続される。負極芯体露出部１４０の一方の外面には、負極集電体２０のリード部１１４が溶接接続される。負極芯体露出部１４０の他方の外面には、負極集電体２０の受け部材１４２が溶接接続される。負極芯体露出部１４０の一方の外面と負極集電体２０のリード部１１４との間には、開口を有する絶縁フィルムが配置され、絶縁フィルムの開口を通じて、負極芯体露出部１４０と負極集電体２０のリード部１１４とが溶接接続される。負極芯体露出部１４０の他方の外面と負極集電体２０の受け部材１４２との間には、開口を有する絶縁フィルム１４６が配置され、絶縁フィルム１４６の開口を通じて、負極芯体露出部１４０と負極集電体２０の受け部材１４２とが溶接接続される。なお、負極集電体２０の受け部材１４２、絶縁フィルム１４６、及び負極芯体露出部１４０の一方の外面と負極集電体２０のリード部１１４との間に配置された絶縁フィルムは必須の構成ではなく、省略することができる。 The negative electrode core exposed portion 140 is electrically connected to a negative terminal 132 serving as an external terminal via the negative electrode current collector 20. The lead portion 114 of the negative electrode current collector 20 is connected to one outer surface of the negative electrode core exposed portion 140 by welding. The receiving member 142 of the negative electrode current collector 20 is connected to the other outer surface of the negative electrode core exposed portion 140 by welding. An insulating film having an opening is disposed between one outer surface of the negative electrode core exposed portion 140 and the lead portion 114 of the negative electrode current collector 20, and the negative electrode core exposed portion 140 and the negative electrode current collector are opened through the opening of the insulating film. The lead portion 114 of the electric body 20 is connected by welding. An insulating film 146 having an opening is disposed between the other outer surface of the negative electrode core exposed portion 140 and the receiving member 142 of the negative electrode current collector 20, and through the opening of the insulating film 146, the negative electrode core exposed portion 140 The receiving member 142 of the negative electrode current collector 20 is connected by welding. The receiving member 142 of the negative electrode current collector 20, the insulating film 146, and the insulating film disposed between one outer surface of the negative electrode core exposed portion 140 and the lead portion 114 of the negative electrode current collector 20 are essential components. Instead, they can be omitted.

また、負極集電体２０は負極側絶縁部材５２ａによって、封口板１２０と電気的に絶縁されている。 Further, the negative electrode current collector 20 is electrically insulated from the sealing plate 120 by the negative electrode side insulating member 52a.

正極端子１３０、負極端子１３２はそれぞれ端子部絶縁部材１５２，１５４を介して封口板１２０に固定されている。本実施形態の二次電池では、正極と正極端子１３０の間に感圧式の電流遮断機構が設けられている。 The positive terminal 130 and the negative terminal 132 are fixed to the sealing plate 120 via terminal insulating members 152 and 154, respectively. In the secondary battery of the present embodiment, a pressure-sensitive current interrupting mechanism is provided between the positive electrode and the positive electrode terminal 130.

電極体１１０は、封口板１２０側を除く周囲を樹脂製の絶縁シート１６１で覆われた状態で、有底筒状の電池ケース１００内に収納されている。電池ケース１００の開口部は封口板１２０により封口されている。封口板１２０には電解液注液孔１６３が設けられている。電解液注液孔１６３は、注液後、封止栓により密閉される。また、封口板１２０には、電流遮断機構の作動圧よりも高いガス圧が加わったときに開放されるガス排出弁１６２が設けられている。 The electrode body 110 is housed in the bottomed cylindrical battery case 100 in a state where the periphery except the sealing plate 120 side is covered with a resin insulating sheet 161. The opening of the battery case 100 is sealed by a sealing plate 120. The sealing plate 120 is provided with an electrolyte injection hole 163. After the electrolyte is injected, the electrolyte injection hole 163 is sealed with a sealing stopper. Further, the sealing plate 120 is provided with a gas discharge valve 162 that is opened when a gas pressure higher than the operating pressure of the current cutoff mechanism is applied.

次に、電流遮断機構について説明するが、この電流遮断機構は、正極側及び負極側のいずれに設けてもよい。以下では正極側にのみ設けるものとして説明する。なお、電流遮断機構は、通電経路の一部に設けられた脆弱部分が、当該脆弱部分近傍の部材が電池ケース１００内の圧力の上昇に伴い、変形することによって破断して通電が断たれるという機構により機能するものである。 Next, the current interrupting mechanism will be described. The current interrupting mechanism may be provided on either the positive electrode side or the negative electrode side. In the following, a description will be given assuming that only the positive electrode is provided. In the current interrupting mechanism, a weak portion provided in a part of the current path is broken by a member near the weak portion as the pressure in the battery case 100 rises, and the current breaking mechanism is broken to cut off the current. It functions by such a mechanism.

図５、図６に示すように、正極端子１３０は内部に貫通孔が形成されている。そして、正極端子１３０は、端子部絶縁部材１５２、封口板１２０及び第２絶縁部材１５０及び導電部材３０のそれぞれに形成された貫通孔内に挿入され、正極端子１３０の電池内部側の先端部が導電部材３０に圧接されるようにカシメられて互いに一体的に固定されている。これにより、正極端子１３０は、端子部絶縁部材１５２及び第２絶縁部材１５０によって封口板１２０とは電気的に絶縁された状態で、導電部材３０と電気的に接続された状態となっている。図には示していないが、図５、図６では、図示された全構成要素の、第２絶縁部材１５０に対して封口板１２０とは反対側に、電極体が存している。なお、正極端子１３０の電池内部側の先端部と導電部材３０の接続部はレーザ溶接等により溶接接続されることが好ましい。また、正極端子１３０に形成された貫通孔は、上端に金属板１５９が設けられたゴム製の端子栓１５８によって封止されている。 As shown in FIGS. 5 and 6, the positive electrode terminal 130 has a through hole formed therein. Then, the positive electrode terminal 130 is inserted into a through hole formed in each of the terminal insulating member 152, the sealing plate 120, the second insulating member 150, and the conductive member 30. It is caulked so as to be pressed against the conductive member 30 and is integrally fixed to each other. Thereby, the positive electrode terminal 130 is in a state of being electrically insulated from the sealing plate 120 by the terminal insulating member 152 and the second insulating member 150 and electrically connected to the conductive member 30. Although not shown in the drawings, in FIGS. 5 and 6, an electrode body exists on the opposite side of the sealing member 120 with respect to the second insulating member 150 of all the illustrated components. It is preferable that the tip of the positive electrode terminal 130 on the battery inner side and the connection between the conductive member 30 are welded and connected by laser welding or the like. The through-hole formed in the positive electrode terminal 130 is sealed by a rubber terminal plug 158 provided with a metal plate 159 at the upper end.

第２絶縁部材１５０は、封口板１２０と導電部材３０の間に配置され、封口板１２０と導電部材３０を絶縁している。導電部材３０は、電極体１１０側に断面が略方形状の筒状部３２を有しており、封口板１２０側には封口板１２０に対して平行に配置されている接続部が形成されている。そして導電部材３０に設けられた貫通孔に正極端子１３０が挿入されている。 The second insulating member 150 is disposed between the sealing plate 120 and the conductive member 30, and insulates the sealing plate 120 from the conductive member 30. The conductive member 30 has a cylindrical portion 32 having a substantially rectangular cross section on the electrode body 110 side, and a connection portion arranged in parallel with the sealing plate 120 is formed on the sealing plate 120 side. I have. The positive terminal 130 is inserted into a through hole provided in the conductive member 30.

導電部材３０の筒状部３２の電極体側の開口部分は、変形板４０によって密閉されている。導電部材３０の筒状部３２の先端部分と変形板４０の周囲とは溶接されている。変形板４０は、金属製であることが好ましく、アルミニウム又はアルミニウム合金製であることがより好ましい。変形板４０は、電池ケース１００内の圧力が増加して所定値になると、変形板４０の中央部が封口板１２０側（電池の外部側）に近づくように変形する。変形板４０の電極体１１０側の面には正極集電体１０が接続される。この正極集電体１０は、金属製であることが好ましく、アルミニウム製又はアルミニウム合金製であることが好ましい。正極集電体１０として、例えば、アルミニウム等の金属板を打ち抜きにより作製したものを使用することができる。以上より、通電経路は、電極体の正極から正極集電体１０、変形板４０、導電部材３０そして正極端子１３０の順で形成されていることになる。 The opening of the cylindrical portion 32 of the conductive member 30 on the side of the electrode body is sealed by a deformable plate 40. The distal end portion of the tubular portion 32 of the conductive member 30 and the periphery of the deformable plate 40 are welded. The deformation plate 40 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy. When the pressure in the battery case 100 increases to a predetermined value, the deformable plate 40 deforms such that the center of the deformable plate 40 approaches the sealing plate 120 side (outside of the battery). The positive electrode current collector 10 is connected to the surface of the deformable plate 40 on the electrode body 110 side. The positive electrode current collector 10 is preferably made of a metal, and is preferably made of aluminum or an aluminum alloy. As the positive electrode current collector 10, for example, a metal plate made of a metal plate such as aluminum by punching can be used. As described above, the conduction path is formed in the order of the positive electrode of the electrode body, the positive electrode current collector 10, the deformable plate 40, the conductive member 30, and the positive electrode terminal 130.

変形板４０の中央部以外と正極集電体１０との間に第１絶縁部材５０が配置されている。第１絶縁部材５０は、変形板４０と正極集電体１０とが接続された変形板の中央部に該当する部分に貫通孔が設けられている。第１絶縁部材５０と第２絶縁部材１５０とは係合により接続・固定されている。固定方法は特に限定されないが、ここでは第１絶縁部材５０に形成された爪部５５，５５を用いてラッチ固定によって固定が行われている。この固定部分は第１絶縁部材５０の外周縁部分に形成されている。 The first insulating member 50 is arranged between a portion other than the center of the deformable plate 40 and the positive electrode current collector 10. The first insulating member 50 has a through hole at a portion corresponding to the center of the deformed plate where the deformed plate 40 and the positive electrode current collector 10 are connected. The first insulating member 50 and the second insulating member 150 are connected and fixed by engagement. The fixing method is not particularly limited, but here, the fixing is performed by latch fixing using the claw portions 55 formed on the first insulating member 50. The fixed portion is formed on the outer peripheral edge portion of the first insulating member 50.

正極集電体１０には、中央部に貫通孔が形成されている。そして図５に示すように、正極集電体１０の中央部の貫通孔の両側にも２つの両脇側の貫通孔がそれぞれ形成されている。また、第１絶縁部材５０には、正極集電体１０の中央に設けられた貫通孔に相対する貫通孔が設けられ、その両側には、正極集電体１０に設けられた両脇側の２つの貫通孔に対応する位置にそれぞれ突起部が形成されている。 In the positive electrode current collector 10, a through hole is formed at the center. As shown in FIG. 5, two through holes on both sides are also formed on both sides of the through hole at the center of the positive electrode current collector 10, respectively. In addition, the first insulating member 50 is provided with a through-hole opposite to the through-hole provided in the center of the positive electrode current collector 10, and on both sides thereof, on both sides provided in the positive electrode current collector 10. Protrusions are formed at positions corresponding to the two through holes, respectively.

これらの第１絶縁部材５０の突起部をそれぞれ正極集電体１０の両脇側の貫通孔に挿入し、突起部の先端部を加熱し拡径することにより第１絶縁部材５０と正極集電体１０とが固定される。 The protrusions of the first insulating member 50 are respectively inserted into the through holes on both sides of the positive electrode current collector 10, and the distal end of the protrusion is heated to increase the diameter, thereby forming the first insulating member 50 and the positive electrode current collector. The body 10 is fixed.

正極集電体１０の中央部の貫通孔の周囲部分には、他の部分よりも厚さが薄くされた周辺領域１８が設けられており、周辺領域１８の外周近傍には、貫通孔を囲むように環状の薄肉部１５が形成されている。この薄肉部１５は厚みが周辺領域１８よりも薄くなるように溝状に設けられたものである。また周辺領域１８の内周縁には内周リブ部１９が設けられ、この内周リブ部１９において変形板４０とレーザ溶接されて変形板４０と正極集電体１０とが電気的に接続されている。変形板４０は略矩形形状を有しており、その中央部に円形の凸部が設けられており、その凸部の周縁部分に内周リブ部１９が溶接されている。なお、内周リブ部１９は必須の構成ではなく、内周リブ部１９を省略することができる。 A peripheral region 18 having a smaller thickness than other portions is provided in a peripheral portion of the central portion of the through hole in the positive electrode current collector 10, and the peripheral region 18 is surrounded by the peripheral region around the through hole. Thus, the annular thin portion 15 is formed. The thin portion 15 is provided in a groove shape so that the thickness is smaller than that of the peripheral region 18. Further, an inner peripheral rib portion 19 is provided on the inner peripheral edge of the peripheral region 18, and the deformable plate 40 is laser-welded to the inner peripheral rib portion 19 to electrically connect the deformable plate 40 and the positive electrode current collector 10. I have. The deforming plate 40 has a substantially rectangular shape, a circular convex portion is provided at the center portion, and the inner peripheral rib portion 19 is welded to a peripheral portion of the convex portion. Note that the inner peripheral rib portion 19 is not an essential component, and the inner peripheral rib portion 19 can be omitted.

本実施形態における電流遮断機構の動作は次の通りである。電池ケース１００内の圧力が大きくなっていき所定値になった時に、変形板４０は変形板４０の中央部が封口板１２０に近づくように変形する。正極集電体１０は内周リブ部１９において変形板４０と溶接されている。そして、薄肉部１５は、正極集電体１０と変形板４０の溶接部分を取り囲んでいる。よって、変形板４０の前述の変形によって、薄肉部１５が全周破断して変形板４０と正極集電体１０との電気的接続が断たれ、電流が遮断される。 The operation of the current cutoff mechanism in the present embodiment is as follows. When the pressure in the battery case 100 increases and reaches a predetermined value, the deformable plate 40 is deformed so that the center of the deformable plate 40 approaches the sealing plate 120. The positive electrode current collector 10 is welded to the deformable plate 40 at the inner peripheral rib portion 19. The thin portion 15 surrounds the welded portion between the positive electrode current collector 10 and the deformable plate 40. Therefore, due to the above-described deformation of the deformable plate 40, the thin portion 15 is broken all around and the electrical connection between the deformable plate 40 and the positive electrode current collector 10 is cut off, and the current is cut off.

本実施形態では、電流遮断機構において薄肉部１５の残肉厚みを従来よりも厚めに設定することにより、電流遮断機構における電池の組み立て工程や部品作成工程に起因する作動圧力のバラツキ要素が存在していても相対的にはバラツキ要素の影響度合を減少させている。ただし、薄肉部１５の残肉厚みのみを大きくすると、電流遮断機構が機能する電池内圧が従来よりも大きくなってしまい、安全性に支障をきたすおそれがあるため、本実施形態では変形板４０の形状を工夫することにより変形板４０を変形させやすくして、電流遮断機構が機能する電池内圧を、薄肉部１５の厚みが小さい従来と同じ圧力となるようにしている。変形板４０の形状について具体的に以下に説明する。 In the present embodiment, by setting the remaining thickness of the thin portion 15 in the current interrupting mechanism to be thicker than before, there is a variation element of the operating pressure due to the battery assembling process and the component creating process in the current interrupting mechanism. Even so, the influence of the variation factor is relatively reduced. However, if only the remaining thickness of the thin portion 15 is increased, the internal pressure of the battery at which the current cutoff mechanism functions becomes larger than before, which may hinder safety. By devising the shape, the deformable plate 40 is easily deformed, and the internal pressure of the battery at which the current interrupting mechanism functions is set to be the same pressure as in the related art in which the thickness of the thin portion 15 is small. The shape of the deformable plate 40 will be specifically described below.

図７は変形板４０のみを電極体１１０が存在している側から見た図（図５，６において下から上に見た図）であって、円形の凸部４２が上側に突き出している側の面である。なお、この図には後に説明する溝を示していない。図７に示す面の凸部４２の周縁部分に正極集電体１０の内周リブ部１９（不図示）が溶接されている。変形板４０は角が丸められた矩形形状を有しており、中央部に円形の凸部４２が形成されていて、電極体１１０の側に凸部４２は突出している。 FIG. 7 is a diagram showing only the deformed plate 40 from the side where the electrode body 110 is present (a diagram seen from bottom to top in FIGS. 5 and 6), and the circular convex portion 42 protrudes upward. Side surface. Note that this figure does not show a groove to be described later. The inner peripheral rib portion 19 (not shown) of the positive electrode current collector 10 is welded to the peripheral portion of the convex portion 42 on the surface shown in FIG. The deforming plate 40 has a rectangular shape with rounded corners, a circular convex portion 42 is formed in the center, and the convex portion 42 projects toward the electrode body 110.

電池ケース１００内の圧力が高まってくると、変形板４０は図５，６において下から上へ圧がかかって押し上げられる（変形板４０が封口板１２０側に押される）ため、図７に示された面内の大部分では圧縮応力が働いている。しかしながら、変形板４０の外周縁は導電部材３０の筒状部３２の先端部分に溶接されて固定されており、円形の凸部４２の周縁部分は正極集電体１０の内周リブ部１９に溶接されているため、これらの溶接部分に近接した部分には引っ張り応力が働いていて、この応力はこの面内でもっとも大きな応力となっている。 When the pressure in the battery case 100 increases, the deformed plate 40 is pressed upward from below in FIGS. 5 and 6 (the deformed plate 40 is pushed toward the sealing plate 120), and thus is shown in FIG. Compressive stress is acting on most of the in-plane. However, the outer peripheral edge of the deformable plate 40 is welded and fixed to the distal end portion of the cylindrical portion 32 of the conductive member 30, and the peripheral edge portion of the circular convex portion 42 is fixed to the inner peripheral rib portion 19 of the positive electrode current collector 10. Because of the welding, a tensile stress acts on a portion close to these welded portions, and this stress is the largest stress in this plane.

定性的には上述の通りであるが、定量的な応力分布を知るために有限要素解析法を用いて、電池ケース１００内の圧力が高くなった場合に変形板４０に生じる応力のシミュレーションを行った。図８，１０，１２に変形板４０の外周縁に働いている応力を矢印により示す。なお、太さと長さで応力の大きさを示す。 Although qualitatively as described above, a simulation of the stress generated in the deformable plate 40 when the pressure in the battery case 100 is increased by using a finite element analysis method to know a quantitative stress distribution. Was. 8, 10, and 12, the stress acting on the outer peripheral edge of the deformable plate 40 is indicated by arrows. The magnitude of the stress is indicated by the thickness and the length.

図８，１０，１２に示すように、変形板４０の外周近傍の表面には、外周に対して垂直な方向の大きな引っ張り応力が働いている。それよりも内側には小さな圧縮応力が働いている。本実施形態では、図９に示すように、変形板４０の一対の長辺６１，６２近傍であって大きな応力が働いている部分に、応力の方向に対して垂直な方向に延びる第１溝７１及び第２溝７２が形成されている。この第１溝７１及び第２溝７２は、一対の長辺６１，６２近傍で最大応力が働いている部分を繋いで形成したものである。 As shown in FIGS. 8, 10, and 12, a large tensile stress in a direction perpendicular to the outer periphery acts on the surface near the outer periphery of the deformed plate 40. A small compressive stress is acting on the inner side. In the present embodiment, as shown in FIG. 9, a first groove extending in a direction perpendicular to the direction of the stress is formed in a portion near a pair of long sides 61 and 62 of the deformed plate 40 where a large stress is applied. 71 and a second groove 72 are formed. The first groove 71 and the second groove 72 are formed by connecting portions where a maximum stress acts near the pair of long sides 61 and 62.

これらの第１溝７１及び第２溝７２は、変形板４０の一対の長辺６１，６２に実質的に平行であって円形の凸部４２よりも一方の長辺６１側に配置された第１溝７１と、他方の長辺６２側に配置された第２溝７２である。なお、円形の凸部４２は正極集電体１０の一部である内周リブ部１９に接続されている。 The first groove 71 and the second groove 72 are substantially parallel to the pair of long sides 61, 62 of the deformable plate 40, and are disposed on one long side 61 side of the circular convex portion 42. One groove 71 and the second groove 72 arranged on the other long side 62 side. Note that the circular convex portion 42 is connected to the inner peripheral rib portion 19 that is a part of the positive electrode current collector 10.

応力が働いている部分に、その応力に垂直な方向の溝や切れ目を入れると応力が働くことによって部材が変形しやすくなり、溝や切れ目がない場合に比べて小さな応力で変形する。従って、第１溝７１及び第２溝７２を設けることによって変形板４０が変形しやすくなっている。そして本実施形態では、従来の構造に比較して薄肉部１５の残肉厚みを大きくすることにより破断強度を大きくしても、電池ケース１００内の圧力が従来と同じ大きさになった時に電流遮断機構を機能させることができる。 When a groove or a cut in a direction perpendicular to the stress is formed in a portion where the stress is applied, the member is easily deformed due to the applied stress, and is deformed with a smaller stress as compared with a case where there is no groove or a cut. Therefore, by providing the first groove 71 and the second groove 72, the deformable plate 40 is easily deformed. In the present embodiment, even when the breaking strength is increased by increasing the remaining thickness of the thin portion 15 as compared with the conventional structure, the current is reduced when the pressure in the battery case 100 becomes the same as the conventional structure. The blocking mechanism can function.

（実施形態２）
実施形態２に係る二次電池は、変形板に形成する溝が実施形態１と異なっており、それ以外の部材や形状等は実施形態１と同じであるので、実施形態１と異なっている部分を以下に説明する。 (Embodiment 2)
The secondary battery according to the second embodiment is different from the first embodiment in the grooves formed in the deformed plate, and the other members and shapes are the same as those in the first embodiment. Will be described below.

本実施形態では図１１に示すように、第１溝７１、第２溝７２に加えて、一対の短辺６３，６４近傍であって大きな応力が働いている部分に応力の方向に対して垂直な方向に延びる第３溝７３および第４溝７４が変形板４３に形成されている。この第３溝７３及び第４溝７４は、一対の短辺６３，６４近傍で最大応力が働いている部分を繋いで形成したものであって、一対の短辺６３，６４に実質的に平行であって円形の凸部４２よりも一方の短辺６３側に配置された第３溝７３と、他方の短辺６４側に配置された第４溝７４である。本実施形態では第３溝７３及び第４溝７４が加えられているので、実施形態１よりもさらに変形板４３が変形しやすくなっている。 In the present embodiment, as shown in FIG. 11, in addition to the first groove 71 and the second groove 72, portions near the pair of short sides 63 and 64 where large stress is applied are perpendicular to the direction of the stress. A third groove 73 and a fourth groove 74 extending in different directions are formed in the deformable plate 43. The third groove 73 and the fourth groove 74 are formed by connecting portions where the maximum stress acts near the pair of short sides 63 and 64, and are substantially parallel to the pair of short sides 63 and 64. The third groove 73 is arranged on one short side 63 side of the circular convex portion 42 and the fourth groove 74 is arranged on the other short side 64 side. In the present embodiment, since the third groove 73 and the fourth groove 74 are added, the deformable plate 43 is more easily deformed than in the first embodiment.

なお、第１溝７１と一方の長辺６１との距離ａは、第３溝７３と一方の短辺６３との距離ｂよりも小さく、ａ＜ｂである。これは長辺６１，６２と凸部４２との距離の方が短辺６３，６４と凸部４２との距離よりも小さいためであって、両端が固定された部分に同じ力がかかった場合に両端の距離が小さい方がその端部に働く応力が大きくなるためである。なお、第１溝７１と一方の長辺６１との距離と、第２溝７２と他方の長辺６２との距離は、必ずしも同じでなくてもよい。また、第３溝７３と一方の短辺６３との距離と、第４溝７４と他方の短辺６４の距離は、必ずしも同じでなくてもよい。 The distance a between the first groove 71 and one long side 61 is smaller than the distance b between the third groove 73 and one short side 63, and a <b. This is because the distance between the long sides 61 and 62 and the convex part 42 is smaller than the distance between the short sides 63 and 64 and the convex part 42, and when the same force is applied to the part where both ends are fixed. This is because the smaller the distance between both ends, the greater the stress acting on the end. Note that the distance between the first groove 71 and one long side 61 and the distance between the second groove 72 and the other long side 62 do not necessarily have to be the same. Further, the distance between the third groove 73 and one short side 63 and the distance between the fourth groove 74 and the other short side 64 do not necessarily have to be the same.

（実施形態３）
実施形態３に係る二次電池は、変形板に形成する溝が実施形態２と異なっており、それ以外の部材や形状等は実施形態２と同じであるので、実施形態２と異なっている部分を以下に説明する。 (Embodiment 3)
The secondary battery according to the third embodiment is different from the second embodiment in the grooves formed in the deformed plate, and the other members and shapes are the same as those in the second embodiment. Will be described below.

本実施形態では図１３に示すように、変形板４５において第１溝７１ａが第３溝７３ａ及び第４溝７４ａと連結されており、第２溝７２ａも第３溝７３ａ及び第４溝７４ａと連結されている。連結に係る曲線部分も変形板４５の外周近傍であって大きな応力が働いている部分に、応力の方向に対して垂直な方向に延びるように設けられている。 In the present embodiment, as shown in FIG. 13, the first groove 71a is connected to the third groove 73a and the fourth groove 74a in the deformed plate 45, and the second groove 72a is connected to the third groove 73a and the fourth groove 74a. Are linked. The curved portion related to the connection is also provided near the outer periphery of the deformable plate 45 and in a portion where a large stress is applied so as to extend in a direction perpendicular to the direction of the stress.

本実施形態では４つの溝７１ａ，７２ａ，７３ａ，７４ａが連結により一つに繋がっているので変形しやすいとともに、溝自体の長さが伸びて変形のしやすさに寄与するため、実施形態２よりもさらに変形板４５が変形しやすくなっている。 In the present embodiment, since the four grooves 71a, 72a, 73a, 74a are connected to each other by connection, they are easily deformed, and the length of the grooves themselves is extended to contribute to the ease of deformation. The deformation plate 45 is more easily deformed than that.

なお、第１溝７１ａと一方の長辺６１との距離は、第３溝７３ａと一方の短辺６３との距離、及び第４溝７４ａと他方の短辺６４の距離よりも小さいことが好ましい。また、第２溝７２ａと他方の長辺６２との距離は、第３溝７３ａと一方の短辺６３との距離、及び第４溝７４ａと他方の短辺６４の距離よりも小さいことが好ましい。これにより、変形板４５がより変形しやすくなる。 Note that the distance between the first groove 71a and one long side 61 is preferably smaller than the distance between the third groove 73a and one short side 63 and the distance between the fourth groove 74a and the other short side 64. . The distance between the second groove 72a and the other long side 62 is preferably smaller than the distance between the third groove 73a and the one short side 63 and the distance between the fourth groove 74a and the other short side 64. . Thereby, the deformation plate 45 is more easily deformed.

（実施形態４）
実施形態４に係る二次電池は、変形板に形成する溝が実施形態１と異なっており、それ以外の部材や形状等は実施形態１と同じであるので、実施形態１と異なっている部分を以下に説明する。 (Embodiment 4)
The secondary battery according to the fourth embodiment differs from the first embodiment in the grooves formed in the deformed plate, and other members and shapes are the same as those in the first embodiment. Will be described below.

本実施形態では実施形態１とは変形板の反対側の面の応力分布（シミュレーションによる）に基づいて変形板の形状を決定している。図１４は図７とは反対側から変形板４１を見た図（図５，６において上から下に見た図）であって、凸部４２は窪んでいる。なお、図７と同様にこの図には後に説明する溝を示していない。図１５は図１４のＤ部分を拡大して応力分布を矢印により表したものである。変形板４１の図１４，１５に示された面では外周縁と凸部４２との間に引っ張り応力が働いている。この応力分布において最大応力かそれに近い応力であって変形板４１の中心部と外周とを結ぶ方向に働いている応力について、応力の向きに対して垂直な方向の溝をつなげて形成すると、図１６に示すような２つのＵ字溝８０ａ，８０ｂとなる。なお、２つのＵ字溝８０ａ，８０ｂの間も溝を形成して両者を繋ぐことは可能であるが、凸部４２が存在しているため、凸部４２近傍の溝加工は難しいので溝加工が比較的容易な場所のみに溝を形成している。また、外周縁部には実施形態１とは逆に圧縮応力が働いている。 In the present embodiment, the shape of the deformed plate is determined based on the stress distribution (by simulation) on the surface on the opposite side of the deformed plate from that of the first embodiment. FIG. 14 is a view of the deformed plate 41 as viewed from the side opposite to that of FIG. 7 (a view as viewed from above in FIGS. 5 and 6), and the convex portions 42 are depressed. Note that, like FIG. 7, a groove described later is not shown in this figure. FIG. 15 is an enlarged view of a portion D in FIG. 14 showing the stress distribution by arrows. 14 and 15 of the deformed plate 41, a tensile stress acts between the outer peripheral edge and the convex portion 42. In this stress distribution, the maximum stress or a stress close thereto and acting in the direction connecting the center portion and the outer periphery of the deformed plate 41 is formed by connecting grooves perpendicular to the direction of the stress. There are two U-shaped grooves 80a and 80b as shown in FIG. Although it is possible to form a groove between the two U-shaped grooves 80a and 80b and connect the two, it is difficult to form a groove near the convex portion 42 because the convex portion 42 is present. However, the groove is formed only in a relatively easy place. Further, a compressive stress acts on the outer peripheral edge, contrary to the first embodiment.

Ｕ字溝８０ａ，８０ｂは、平面視（図１６を上から見た場合）においてＵ字の形状を有しており、Ｕ字の縦棒２本にあたる略平行な一対の直線状の溝８１ａ，８１ｂは、変形板４１の一対の長辺６１，６２間の中心線を挟んで長辺６１，６２に沿って延びている。ここで、変形板４１の一対の長辺６１，６２間の中心線とは、長辺６１及び長辺６２のそれぞれから等距離の位置にあって、長辺６１及び長辺６２に対して平行に延びる線である。 The U-shaped grooves 80a and 80b have a U-shape in a plan view (when FIG. 16 is viewed from above), and a pair of substantially parallel linear grooves 81a, which correspond to two U-shaped vertical bars. 81b extends along the long sides 61, 62 with a center line between the pair of long sides 61, 62 of the deformable plate 41 interposed therebetween. Here, the center line between the pair of long sides 61 and 62 of the deformed plate 41 is at a position equidistant from each of the long sides 61 and 62 and is parallel to the long sides 61 and 62. It is a line extending to.

また、一対の直線状の溝８１ａ，８１ｂを結ぶ、Ｕ字の底にあたる部分の溝８２ａ，８２ｂは、一対の直線状の溝８１ａ，８１ｂよりも変形板４１の周縁側（近い方の短辺側）に位置している。つまり変形板４１を一対の長辺６１，６２のそれぞれの真ん中を結ぶ線で２つに分けたときに、Ｕ字溝８０ａ，８０ｂはそれぞれの外周に略平行な形状となっている。 Further, the grooves 82a and 82b at the bottom of the U-shaped portion connecting the pair of linear grooves 81a and 81b are closer to the peripheral edge (closer short side) of the deformable plate 41 than the pair of linear grooves 81a and 81b. Side). That is, when the deformed plate 41 is divided into two parts by a line connecting the middles of the pair of long sides 61 and 62, the U-shaped grooves 80a and 80b have shapes substantially parallel to the respective outer circumferences.

本実施形態でも、２つのＵ字溝８０ａ，８０ｂを設けることによって変形板４１が変形しやすくなって、実施形態１と同様の効果を奏する。 Also in the present embodiment, by providing the two U-shaped grooves 80a and 80b, the deformable plate 41 is easily deformed, and the same effect as in the first embodiment is obtained.

（実施形態５）
実施形態５に係る二次電池は、変形板に形成する溝が実施形態１と異なっており、それ以外の部材や形状等は実施形態１と同じであるので、実施形態１と異なっている部分を以下に説明する。 (Embodiment 5)
The secondary battery according to the fifth embodiment is different from the first embodiment in the grooves formed in the deformed plate, and the other members and shapes are the same as those in the first embodiment. Will be described below.

本実施形態では変形板の凸部４２が突出している側の面に、実施形態１に示す第１溝７１，第２溝７２が形成されており、反対側の面に実施形態４に示す２つのＵ字溝８０ａ，８０ｂが形成されている。このような２種類の溝が形成されていることにより、実施形態１よりも変形板がさらに変形しやすくなっている。 In the present embodiment, the first groove 71 and the second groove 72 shown in the first embodiment are formed on the surface of the deformed plate on the side where the convex portion 42 protrudes, and the second groove shown in the fourth embodiment is formed on the opposite surface. U-shaped grooves 80a and 80b are formed. By forming such two types of grooves, the deformable plate is more easily deformed than in the first embodiment.

（その他の実施形態）
上述の実施形態は本願発明の例示であって、本願発明はこれらの例に限定されず、これらの例に周知技術や慣用技術、公知技術を組み合わせたり、一部置き換えたりしてもよい。また当業者であれば容易に思いつく改変発明も本願発明に含まれる。 (Other embodiments)
The above-described embodiment is an exemplification of the present invention, and the present invention is not limited to these examples, and well-known technology, conventional technology, and known technology may be combined with these examples or partially replaced. Modified inventions easily conceived by those skilled in the art are also included in the present invention.

実施形態５は実施形態１と実施形態４とを組み合わせた形態であるが、実施形態２と実施形態４とを組み合わせてもよいし、実施形態３と実施形態４とを組み合わせてもよい。 The fifth embodiment is a mode in which the first embodiment and the fourth embodiment are combined, but the second embodiment and the fourth embodiment may be combined, or the third embodiment and the fourth embodiment may be combined.

本願発明の二次電池は、非水電解質二次電池に対しても、ニッケル−水素二次電池等のアルカリ二次電池に対しても適用可能である。また、変形板は、正極集電体及び負極集電体の何れか一方に接続されていれば所定の作用効果が奏されるが、両方に接続されていてもよい。 The secondary battery of the present invention is applicable to both non-aqueous electrolyte secondary batteries and alkaline secondary batteries such as nickel-hydrogen secondary batteries. The deformed plate has a predetermined effect if it is connected to one of the positive electrode current collector and the negative electrode current collector, but may be connected to both.

電池ケースは、直方体形状（角形）に限定されず、有底の円筒形状であってもよい。また、導電部材の筒状部も、筒の横断面が長方形に限定されず、円形や楕円形、多角形であっても構わない。 The battery case is not limited to a rectangular parallelepiped shape (square), and may be a cylindrical shape with a bottom. Also, the cross-section of the cylindrical portion of the conductive member is not limited to a rectangle, but may be a circle, an ellipse, or a polygon.

電流遮断機構の、電流の遮断が行われる脆弱部分は、正極集電体及び負極集電体の少なくとも一方に設けられていてもよいし、変形板に設けられていてもよいし、集電体と変形板との接続部分に設けられていてもよい。あるいは、集電体と変形板とを金属箔で接続して、この金属箔を脆弱部分としてもよく、例えば集電体に開口を設け、この開口を塞ぐように金属箔を集電体に接続するとともに、変形板にも金属箔を接続させる形態が考えられる。また、脆弱部分は、周辺部分よりも薄肉にした薄肉部にしてもよいし、切り込みやノッチなどにしてもよく、あるいは溶接部分（溶接ナゲット）としてもよい。 The fragile portion of the current interrupting mechanism where the current is interrupted may be provided on at least one of the positive electrode current collector and the negative electrode current collector, may be provided on a deformed plate, or may be provided on the current collector. May be provided at the connection between the and the deformable plate. Alternatively, the current collector and the deformable plate may be connected to each other with a metal foil, and the metal foil may be a fragile portion. For example, an opening is provided in the current collector, and the metal foil is connected to the current collector so as to close the opening. In addition, a form in which a metal foil is connected to the deformed plate is also conceivable. Further, the fragile portion may be a thin portion made thinner than the peripheral portion, a notch or a notch, or a welded portion (weld nugget).

変形板を平面視したとき、変形板の短手方向の長さ（一対の長辺間の距離）は、変形板の長手方向の長さ（一対の短辺間の距離）に対して、１．１〜５倍であることが好ましく、１．２〜４倍であることが好ましく、１．５〜３倍であることがさらに好ましい。 When the deformed plate is viewed in plan, the length of the deformed plate in the short direction (distance between a pair of long sides) is 1 to the length of the deformed plate in the longitudinal direction (distance between a pair of short sides). 0.1 to 5 times, preferably 1.2 to 4 times, and more preferably 1.5 to 3 times.

変形板に形成される溝は、両面のうちいずれの面に形成されていてもよい。また、溝の形状も特に限定されず、断面がＶ字であってもよいし、Ｕ字であってもよく、その他の形状であってもよい。また、溝は変形板を研削等して窪みのみとして形成されていてもよいし、一方の面が凹み他方の面が突出している形状に形成されていてもよい。 The groove formed in the deformed plate may be formed on any of the two surfaces. Also, the shape of the groove is not particularly limited, and the cross section may be V-shaped, U-shaped, or another shape. Further, the groove may be formed as only a depression by grinding the deformed plate or the like, or may be formed in a shape in which one surface is concave and the other surface is protruding.

また、実施形態１においては、外部端子と導電部材が別部品からなる例を示したが、外部端子と導電部材を一つの部品とすることもできる。 Further, in the first embodiment, an example is described in which the external terminal and the conductive member are formed of different components, but the external terminal and the conductive member may be formed as one component.

１０正極集電体
２０負極集電体
３０導電部材
４０，４１，４３，４５変形板
５０第１絶縁部材
６１，６２長辺
６３，６４短辺
７１，７１ａ第１溝
７２，７２ａ第２溝
７３，７３ａ第３溝
７４，７４ａ第４溝
８０ａ，８０ｂＵ字溝
８１ａ，８１ｂＵ字溝を構成する実質的に平行な一対の直線状の溝
８２ａ，８２ｂＵ字溝を構成する実質的に平行な一対の直線状の溝
１００電池ケース
１１０電極体
１２０封口板
１３０正極端子（外部端子）
１３２負極端子（外部端子） Reference Signs List 10 positive electrode current collector 20 negative electrode current collector 30 conductive member 40, 41, 43, 45 deformed plate 50 first insulating member 61, 62 long side 63, 64 short side 71, 71a first groove 72, 72a second groove 73 , 73a Third groove 74, 74a Fourth groove 80a, 80b U-shaped groove 81a, 81b A pair of substantially parallel linear grooves 82a, 82b forming a U-shaped groove substantially parallel forming a U-shaped groove A pair of straight grooves 100 Battery case 110 Electrode body 120 Sealing plate 130 Positive terminal (external terminal)
132 Negative electrode terminal (external terminal)

Claims

開口を有する電池ケースと、
前記電池ケースに収納された、正極および負極を含む電極体と、
前記正極又は負極に電気的に接続された集電体と、
前記電池ケースの前記開口を封口する封口板と、
前記封口板に取り付けられた外部端子と、
前記封口板と前記電極体との間に位置し、前記外部端子に電気的に接続され、前記電極体側に開口部分を有する導電部材と、
前記開口部分を密閉し、前記集電体に接続され、前記電池ケース内の圧力が所定値となったときに変形する変形板と
を備え、
前記変形板は略矩形形状を有していて、一対の長辺と一対の短辺を有しているとともに、前記長辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも一方の前記長辺側に配置される第１溝と、前記長辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも他方の前記長辺側に配置される第２溝とを有する、二次電池。 A battery case having an opening;
An electrode body containing a positive electrode and a negative electrode housed in the battery case,
A current collector electrically connected to the positive electrode or the negative electrode,
A sealing plate for sealing the opening of the battery case,
An external terminal attached to the sealing plate,
A conductive member located between the sealing plate and the electrode body, electrically connected to the external terminal, and having an opening on the electrode body side;
A deformable plate that seals the opening, is connected to the current collector, and deforms when the pressure in the battery case reaches a predetermined value.
The deformable plate has a substantially rectangular shape, has a pair of long sides and a pair of short sides, and is substantially parallel to the long side, and the deformable plate and the current collector A first groove disposed on one of the long sides relative to the connection with the body, and a first groove substantially parallel to the long side and closer to the connection between the deformable plate and the current collector; A secondary battery having a second groove disposed on the other long side.

前記変形板は、前記短辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも一方の前記短辺側に配置される第３溝と、前記短辺に対して実質的に平行であって且つ前記変形板と前記集電体との接続部よりも他方の前記短辺側に配置される第４溝とを有する、請求項１に記載の二次電池。 A third groove that is substantially parallel to the short side and that is disposed on one of the short sides relative to a connection portion between the deformable plate and the current collector; 2. The second groove according to claim 1, further comprising a fourth groove that is substantially parallel to a side and that is arranged on the other short side of the connection between the deformable plate and the current collector. 3. Next battery.

前記一方の前記長辺と前記第１溝との間の距離及び前記他方の前記長辺と前記第２溝との間の距離は、前記一方の前記短辺と前記第３溝との間の距離及び前記他方の前記短辺と前記第４溝との間の距離よりも小さい、請求項２に記載の二次電池。 The distance between the one long side and the first groove and the distance between the other long side and the second groove are between the one short side and the third groove. 3. The secondary battery according to claim 2, wherein the distance is smaller than a distance and a distance between the other short side and the fourth groove. 4.

前記第１溝は前記第３溝及び前記第４溝と連結されており、
前記第２溝は前記第３溝及び前記第４溝と連結されている、請求項２又は３に記載の二次電池。 The first groove is connected to the third groove and the fourth groove,
4. The secondary battery according to claim 2, wherein the second groove is connected to the third groove and the fourth groove. 5.

前記変形板は平面視においてＵ字形状のＵ字溝をさらに有しており、
前記Ｕ字溝を構成する実質的に平行な一対の直線状の溝は、前記一対の前記長辺間の中心線を挟んで前記長辺に沿って延びており、
前記Ｕ字溝の前記一対の直線状の溝を結ぶ部分は前記一対の直線状の溝よりも前記変形板の周縁側に位置している、請求項１から４のいずれか一つに記載の二次電池。 The deformed plate further has a U-shaped groove in a U shape in plan view,
A pair of substantially parallel linear grooves constituting the U-shaped groove extend along the long side with a center line between the pair of the long sides interposed therebetween,
5. The U-shaped groove according to claim 1, wherein a portion connecting the pair of linear grooves is located closer to a peripheral edge of the deformable plate than the pair of linear grooves. 6. Secondary battery.

開口を有する電池ケースと、
前記電池ケースに収納された、正極および負極を含む電極体と、
前記正極又は負極に電気的に接続された集電体と、
前記電池ケースの前記開口を封口する封口板と、
前記封口板に取り付けられた外部端子と、
前記封口板と前記電極体との間に位置し、前記外部端子に電気的に接続され、前記電極体側に開口部分を有する導電部材と、
前記開口部分を密閉し、前記集電体に接続され、前記電池ケース内の圧力が所定値となったときに変形する変形板と
を備え、
前記変形板は略矩形形状を有していて、略矩形形状の中央部分において前記集電体と接続されているとともに、平面視においてＵ字形状のＵ字溝を有しており、
前記Ｕ字溝を構成する実質的に平行な一対の直線状の溝は、略矩形形状の２つの長辺間の中心線を挟んで前記長辺に沿って延びており、
前記Ｕ字溝の前記一対の直線状の溝を結ぶ部分は前記一対の直線状の溝よりも前記変形板の周縁側に位置している、二次電池。 A battery case having an opening;
An electrode body containing a positive electrode and a negative electrode housed in the battery case,
A current collector electrically connected to the positive electrode or the negative electrode,
A sealing plate for sealing the opening of the battery case,
An external terminal attached to the sealing plate,
A conductive member located between the sealing plate and the electrode body, electrically connected to the external terminal, and having an opening on the electrode body side;
A deformable plate that seals the opening, is connected to the current collector, and deforms when the pressure in the battery case reaches a predetermined value.
The deformed plate has a substantially rectangular shape, is connected to the current collector at a central portion of the substantially rectangular shape, and has a U-shaped groove having a U shape in plan view,
A pair of substantially parallel linear grooves constituting the U-shaped groove extend along the long side with a center line between two substantially rectangular long sides,
The secondary battery, wherein a portion of the U-shaped groove connecting the pair of linear grooves is located closer to the periphery of the deformable plate than the pair of linear grooves.