JP5806641B2 - Method for forming explosion-proof valve for battery case lid - Google Patents

Method for forming explosion-proof valve for battery case lid Download PDF

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JP5806641B2
JP5806641B2 JP2012116482A JP2012116482A JP5806641B2 JP 5806641 B2 JP5806641 B2 JP 5806641B2 JP 2012116482 A JP2012116482 A JP 2012116482A JP 2012116482 A JP2012116482 A JP 2012116482A JP 5806641 B2 JP5806641 B2 JP 5806641B2
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groove
breaking
battery case
lid
forming
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JP2013243075A (en
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小西　晴之
晴之 小西
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Kobe Steel Ltd
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Kobe Steel Ltd
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Priority to KR20130057028A priority patent/KR101490592B1/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
    • H01M2220/00—Batteries for particular applications
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • 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

Description

本発明は、電池ケース蓋であって、所定の内部圧力がかかると、その内部圧力を開放する防爆弁（防爆機構）を備えた電池ケース蓋の防爆弁の形成方法に関するものである。 The present invention relates to a battery case lid, the predetermined internal pressure is applied, it relates to an explosion-proof valve forming method of the explosion-proof valve of batteries case lid provided with a (explosion-proof mechanism) for releasing the internal pressure.

携帯電話やノート型パーソナルコンピュータ等の電源として、リチウムイオン二次電池が広く使用されている。この電池ケースを構成する板材には、その蓋を含めて金属が使用されていることが多く、特許文献１〜３ではＳＵＳ等の鉄合金が、特許文献４〜７ではアルミニウム合金が使用された電池ケースが開示されている。特に、電池ケースの蓋や本体などをアルミニウム合金板素材から構成させると、耐食性や軽量化および加工性やコスト面からも有利である。   Lithium ion secondary batteries are widely used as power sources for mobile phones, notebook personal computers, and the like. In many cases, a metal including the lid is used for the plate material constituting the battery case. In Patent Documents 1 to 3, an iron alloy such as SUS is used, and in Patent Documents 4 to 7, an aluminum alloy is used. A battery case is disclosed. In particular, it is advantageous in terms of corrosion resistance, weight reduction, workability, and cost when the battery case lid, body, and the like are made of an aluminum alloy plate material.

この二次電池の外装であるケース（以下、電池ケース）は、電池の充放電や使用環境下の温度上昇によって内部圧力が上昇することがあり、この内部圧力で電池ケースが変形したり、さらには破裂する危険性を抱えている。このような電池ケースの破裂を防ぐため、破裂しない程度の内部圧力で電池ケースの一部が開裂して内部圧力を開放するような、安全装置としての防爆弁（防爆機構）が設けられている。   The case that is the exterior of the secondary battery (hereinafter referred to as the battery case) may have an internal pressure that increases due to the charging / discharging of the battery or a temperature increase in the usage environment. Has the risk of bursting. In order to prevent the battery case from rupturing, an explosion-proof valve (explosion-proof mechanism) is provided as a safety device so that a part of the battery case is ruptured to release the internal pressure with an internal pressure that does not rupture. .

一般的な防爆弁の構造は、電池ケースを構成する蓋などの板材の一部を溝状に薄肉加工して破断用凹溝（薄肉部）としたもので、この凹溝を内部圧力の小幅な上昇で選択的に破断、開裂させるものである。具体的には、蓋などの薄肉部内に、平面視が楕円形あるいは直線状の破断用凹溝を加工して設け、電池内部でのガス発生などの異常時には、この破断用凹溝の材料が破断して内部のガスを放出し、電池の爆発を防止するものである。   The general explosion-proof valve structure is made by thinning a part of a plate material such as a lid constituting a battery case into a groove shape to form a groove for breaking (thin wall portion). It can be selectively broken and cleaved by a simple rise. Specifically, in a thin part such as a lid, a breaking groove having an elliptical or linear shape in plan view is provided by machining, and when there is an abnormality such as gas generation inside the battery, the material of the breaking groove is It breaks and releases internal gas, preventing battery explosion.

例えば、特許文献８では、蓋体の平坦部の一部に平面視で円形の薄肉部を設けて、ここに、更に薄肉の環状凹溝（破断用凹溝）を二つ、間隔をあけて二重として設け、円形の内側の環状凹溝をより薄肉としている。そして、外側の環状凹溝を高圧用安全弁とし、円形の内側の環状凹溝を低圧用安全弁として形成している。そして、前記電池ケース内部の圧力変化に応じて、前記第１の薄肉部と第２の薄肉部の少なくとも一方を開裂させて内部気体を外部に放出するように構成している。ここで、高圧用安全弁は、円環状の薄肉平坦部（第１の薄肉部）と、この薄肉平坦部に囲まれた第１領域とをプレス加工により形成している。一方、低圧用安全弁は蓋の前記第１領域内に有底穴を切削加工あるいはプレス加工することにより形成している。   For example, in Patent Document 8, a circular thin wall portion is provided in a part of the flat portion of the lid body in a plan view, and two thin annular groove grooves (breaking groove grooves) are further provided at intervals. It is provided as a double, and the circular concave groove inside the circle is made thinner. The outer annular groove is formed as a high-pressure safety valve, and the circular inner annular groove is formed as a low-pressure safety valve. And according to the pressure change inside the battery case, at least one of the first thin part and the second thin part is cleaved to release the internal gas to the outside. Here, the high-pressure safety valve forms an annular thin flat portion (first thin portion) and a first region surrounded by the thin flat portion by press working. On the other hand, the safety valve for low pressure is formed by cutting or pressing a bottomed hole in the first region of the lid.

ここで、蓋体などの薄板材の一部を防爆弁として溝状に薄肉加工する方法としては、特許文献１、２には貫通孔を形成した板材と別の板材とを貼り合わせる方法が、特許文献３にはダイとポンチを用いた冷間鍛造による方法が、特許文献４〜７にはプレス加工による方法がそれぞれ開示されている。   Here, as a method of thinly processing a part of a thin plate material such as a lid into a groove shape as an explosion-proof valve, Patent Documents 1 and 2 include a method of bonding a plate material having a through hole and another plate material, Patent Document 3 discloses a method by cold forging using a die and a punch, and Patent Documents 4 to 7 each disclose a method by press working.

前記薄肉部の形状としては、平面視で、特許文献２、５は１本の直線、特許文献１、４、６は十字型等の１点以上で交差する複数の直線からなり、特許文献３、７、８は環状と、様々な形状が開示されている。   As the shape of the thin-walled portion, in a plan view, Patent Documents 2 and 5 include a single straight line, and Patent Documents 1, 4, and 6 include a plurality of straight lines that intersect at one or more points such as a cross shape. , 7 and 8 are annular and various shapes are disclosed.

これら薄肉部を設ける部位として、特許文献１、２、８は蓋（封口板）に、特許文献４、５は本体広面、特許文献６は本体広面または本体狭面としている。また、特許文献９では、小さな負荷では広面である正背面と比較して変形を生じにくい電池ケース本体の幅狭面である側面に防爆弁を設けている。   Patent Documents 1, 2, and 8 are the lids (sealing plates), Patent Documents 4 and 5 are the main body wide surface, and Patent Document 6 is the main body wide surface or the main body narrow surface. Moreover, in patent document 9, the explosion-proof valve is provided in the side surface which is a narrow surface of a battery case main body which is hard to produce a deformation | transformation compared with the front back surface which is a wide surface with a small load.

特開平５−３１４９５９号公報JP-A-5-314959 特開２００２−８３５７８号公報JP 2002-83578 A 特開２００５−２５１４４７号公報JP 2005-251447 A 特開２００１−３５４６７号公報JP 2001-35467 A 特開２００１−３４５０８３号公報JP 2001-345083 A 特開２００１−１４３６６４号公報JP 2001-143664 A 特開平１１−２０４０９３号公報JP-A-11-204093 特開２００３−２９７３２３号公報JP 2003-297323 A 特開２００９−４２７１号公報JP 2009-4271 A

電池ケースが破裂する前に、防爆弁である破断用凹溝を確実に開裂させるためには、この数十μｍから数百μｍ単位となるごく薄い厚さ（板厚、肉厚）を有する、破断用凹溝や蓋の薄肉部の残厚の精度や形状精度の確保が必須である。これに対して、前記従来技術における、冷間鍛造あるいは切削加工、プレス加工などでは、前記ミクロな厚さ（肉厚）を有する、特に前記破断用凹溝の残厚の精度や形状精度の確保が困難である。   In order to surely cleave the breaking groove as an explosion-proof valve before the battery case ruptures, it has a very thin thickness (plate thickness, wall thickness) of several tens μm to several hundreds μm. It is essential to ensure the accuracy and shape accuracy of the remaining thickness of the breaking groove and the thin part of the lid. On the other hand, in cold forging, cutting, pressing, etc. in the prior art, ensuring the accuracy and shape accuracy of the remaining thickness of the groove for breaking, especially the micro thickness (wall thickness). Is difficult.

これに対して、公知のコイニング加工は、元の素材板から蓋をプレス加工により製作する一環として、前記ごく薄い厚さを有する破断用凹溝や蓋の薄肉部を、残厚の精度や形状精度良く、効率良く加工することができる。   On the other hand, the known coining process, as part of manufacturing the lid from the original material plate by press working, the breaking groove and the thin part of the lid having a very thin thickness, the accuracy and shape of the remaining thickness It can be processed accurately and efficiently.

図６に示すように、コイニング加工は、基台（剛体）１３上に蓋２０（板材）を固定し、上部から突起（凸条、刃物状）２３を設けた金型２２を蓋２０に押し付け加圧して、前記金型２２の突起２３により、防爆弁として機能する破断用凹溝２１を薄肉部３に刻印加工する。このようなコイニング加工は、前記冷間鍛造あるいは切削加工に比して効率的であり、前記蓋２０の薄肉部３や破断用凹溝２１の残厚の精度や形状精度の確保が図れる。   As shown in FIG. 6, coining is performed by fixing a lid 20 (plate material) on a base (rigid body) 13 and pressing a mold 22 provided with projections (projections, blades) 23 from the top against the lid 20. By applying pressure, the breaking groove 21 that functions as an explosion-proof valve is stamped on the thin portion 3 by the protrusion 23 of the mold 22. Such coining is more efficient than the cold forging or cutting, and the accuracy of the remaining thickness and the shape accuracy of the thin portion 3 of the lid 20 and the breaking groove 21 can be ensured.

ただ、これは剛性が高い前記ＳＵＳ等の鉄合金や鋼について言えることであって、軟質で、かつ弾性係数が低い特性を有するアルミニウム合金板では、これを素材とする蓋では、前記コイニング加工によっても、特に前記破断用凹溝２１の残厚の精度や形状精度の確保が困難となる。   However, this can be said for iron alloys and steels such as SUS having a high rigidity. In the case of an aluminum alloy plate that is soft and has a low elastic modulus, the lid made of this is made by the coining process. In particular, it is difficult to ensure the accuracy of the remaining thickness and the shape accuracy of the breaking groove 21 for breaking.

より具体的に、蓋２０のアルミニウム合金板（板材）の前記薄肉部３に、前記破断用凹溝２１をコイニング加工した場合、形成する前記破断用凹溝２１の裏側（破断用凹溝加工の底側）に、矢印で示す「くびれ（へこみ）」が発生しやすくなる。このくびれは、破断用凹溝２１の延在方向に部分的あるいは局部的に発生するため、発生の程度や発生部位によって、破断用凹溝２１の肉厚（板厚）が部分的に薄くなり，防爆弁の作動圧が安定せず、破裂する前に確実に開裂するような防爆機構とならない場合が生じる。   More specifically, when the breaking groove 21 is coined in the thin portion 3 of the aluminum alloy plate (plate material) of the lid 20, the back side of the breaking groove 21 to be formed (of the breaking groove processing). On the bottom side, “necking” indicated by an arrow tends to occur. Since this constriction occurs partially or locally in the extending direction of the breaking groove 21, the thickness (plate thickness) of the breaking groove 21 is partially reduced depending on the degree of occurrence and the location of the occurrence. , Explosion-proof valve operating pressure is not stable, and an explosion-proof mechanism that reliably breaks before bursting may not occur.

このようなくびれは、前記金型でコイニング加工するときの、前記突起の下降（押し付け）にて左右に押し分けられるアルミニウム合金材料の移動（左方向の矢印で示す）の仕方が、蓋２０のアルミニウム合金板薄肉部３の矢印で示す「たわみ」によって不均一になるために生じる。この傾向は、素材がアルミニウム合金板である場合の顕著な特徴であって、剛性が高い前記ＳＵＳ等の鉄合金製や鋼製の蓋では、肉厚（板厚）が同様に薄くても発生しにくい。   Such constriction is caused by the movement of the aluminum alloy material (indicated by a left arrow) that is pushed to the left and right when the protrusion is lowered (pressed) when coining is performed with the mold. This is caused by non-uniformity caused by “deflection” indicated by an arrow in the thin portion 3 of the alloy plate. This tendency is a prominent feature when the material is an aluminum alloy plate, and it occurs even when the wall thickness (plate thickness) is thin in the case of a lid made of iron alloy or steel such as SUS having high rigidity. Hard to do.

また、アルミニウム合金板は軟質であるので、これを素材とする蓋では、蓋本体の他の部分を極端に変形させずに、前記薄肉部や破断用凹溝を破断させるためには、前記薄肉部や破断用凹溝の板厚を一層薄くする必要がある。例えば、実際に前記薄肉部の板厚は１００μｍ、破断用凹溝の板厚は３０μｍ程度と極薄となる。このため、この破断用凹溝を前記金型でコイニング加工するときの、蓋のアルミニウム合金板のたわみの不均一性の発生や、形成する前記破断用凹溝加工部の底の前記くびれの発生はより激しくなる。   In addition, since the aluminum alloy plate is soft, in the lid made of this, in order to break the thin portion and the breaking groove without excessively deforming other portions of the lid main body, the thin wall It is necessary to further reduce the thickness of the groove and the groove for breaking. For example, the plate thickness of the thin portion is actually 100 μm, and the plate thickness of the breaking groove is about 30 μm, which is extremely thin. For this reason, when the recess groove for breaking is coined with the mold, the occurrence of unevenness of the deflection of the aluminum alloy plate of the lid and the occurrence of the constriction at the bottom of the groove forming portion for the break to be formed Becomes more intense.

本発明は、このような問題点に鑑みてなされたものであり、薄肉なアルミニウム合金製蓋であっても、前記コイニング加工によって前記破断用凹溝を精度よく加工することができ、破裂する前に、設定どおりの作動圧力で確実に開裂する防爆機構を備える電池ケースの蓋の防爆弁の形成方法を提供することを目的とする。 The present invention has been made in view of such problems, and even with a thin aluminum alloy lid, the breaking groove can be processed with high precision by the coining process, before being ruptured. to, and to provide a method of forming a safety vent lid securely Ru batteries case with the explosion-proof mechanism which cleaves at a working pressure of configured.

上記目的達成のために、本発明の電池ケース蓋の防爆弁の形成方法の要旨は、厚さ０．５〜２ｍｍのアルミニウム合金板からなる前記電池ケース蓋のプレス加工によって、この電池ケース蓋に厚さ５０〜３００μｍの薄肉な平坦状凹部を形成した後、この平坦状凹部に厚さ１０〜１００μｍのより薄肉な破断用凹溝を更にコイニング加工により形成するに際し、この破断用凹溝に対して、この破断用凹溝よりも厚肉だが前記平坦状凹部よりも薄肉な凹溝を、この破断用凹溝に対して互いに間隔をあけて並列させて、この破断用凹溝と同時にコイニング加工により形成することである。 To achieve the above object, the gist of the battery case lid explosion-proof valve of the present invention is that the battery case lid is formed by pressing the battery case lid made of an aluminum alloy plate having a thickness of 0.5 to 2 mm. After forming a thin flat concave portion having a thickness of 50 to 300 μm, a thinner breaking groove having a thickness of 10 to 100 μm is further formed in the flat concave portion by coining. Then, a groove that is thicker than the breaking groove but thinner than the flat groove is arranged parallel to the breaking groove, and coining is performed simultaneously with the breaking groove. It is to form by.

本発明によれば、前記した薄肉なアルミニウム合金製蓋であっても、コイニング加工によって、極薄の破断用凹溝を精度よく加工することができる。この結果、電池ケースが破裂する前に、電池ケースの蓋の防爆弁を確実に開裂することができる。   According to the present invention, even with the above-described thin aluminum alloy lid, it is possible to accurately process an extremely thin breaking groove by coining. As a result, the explosion-proof valve of the battery case lid can be reliably opened before the battery case is ruptured.

本発明電池ケース蓋の一態様を斜視図と断面図とで示す説明図である。It is explanatory drawing which shows the aspect of this invention battery case cover with a perspective view and sectional drawing. 本発明電池ケース蓋の他の態様を斜視図と断面図とで示す説明図である。It is explanatory drawing which shows the other aspect of this invention battery case cover with a perspective view and sectional drawing. 本発明電池ケース蓋の一態様を平面図と側面図とで示す説明図である。It is explanatory drawing which shows the one aspect | mode of this invention battery case cover with a top view and a side view. 図３の○で囲んだＡを拡大して断面図で示す説明図である。It is explanatory drawing which expands A enclosed by (circle) of FIG. 3, and is shown with sectional drawing. 本発明電池ケース蓋のコイニング加工を示す断面図である。It is sectional drawing which shows coining process of this invention battery case cover. 従来の電池ケース蓋のコイニング加工を示す断面図である。It is sectional drawing which shows the coining process of the conventional battery case cover.

以下に図面を参照しながら、本発明の好適な実施の形態について詳細に説明する。なお、本明細書及び図面において、実質的に同一の機能構成を有する構成要素については、同一の符号を付することにより重複説明を省略する。   Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

図１、２に、本発明電池ケース蓋の各実施形態を、上側に全体斜視図、下側にその一部の断面図とで各々示す。図１、２に示すように、本発明電池ケース蓋１は、一定の板厚を有するアルミニウム合金薄板をプレス加工により成形してなり、全体が平板状の形状を有している。   1 and 2 show embodiments of the battery case lid of the present invention in an overall perspective view on the upper side and a partial cross-sectional view on the lower side. As shown in FIGS. 1 and 2, the battery case lid 1 of the present invention is formed by pressing an aluminum alloy thin plate having a constant plate thickness, and has a flat plate shape as a whole.

ここで、蓋１の素材であるアルミニウム合金薄板、あるいは成形された本発明電池ケース蓋１の厚さ（板厚）は、前記した携帯電話やノート型パーソナルコンピュータあるいは自動車用等の電源である、リチウムイオン二次電池ケースの蓋として、０．５〜２ｍｍの範囲とする。電池ケース蓋１の厚さが０．５ｍｍ未満では、３０００系、５０００系、６０００系の中でも比較的高強度なアルミニウム合金薄板を蓋の素材として用いたとしても、蓋として要求される剛性や強度が不足する。一方、電池ケース蓋１の厚さが２ｍｍを越えると、電池ケース本体をアルミニウム合金薄板としても、重量が重くなるとともに、厚さが厚くなって、薄肉部や破断用凹溝などの防爆弁の精度の良い加工が難しくなる。また、前記した本発明の課題である、破断用凹溝のコイニング加工の際の、蓋のたわみの不均一性の発生や破断用凹溝底部のくびれの発生などが起きにくく、本発明の適用自体が不要となる。   Here, the thickness (plate thickness) of the aluminum alloy thin plate which is the material of the lid 1 or the molded battery case lid 1 of the present invention is a power source for the above-described mobile phone, notebook personal computer, automobile, etc. The lid of the lithium ion secondary battery case is in the range of 0.5 to 2 mm. If the thickness of the battery case lid 1 is less than 0.5 mm, the rigidity and strength required for the lid can be obtained even if a relatively high-strength aluminum alloy thin plate is used as the lid material among the 3000 series, 5000 series, and 6000 series. Is lacking. On the other hand, if the thickness of the battery case lid 1 exceeds 2 mm, even if the battery case body is made of an aluminum alloy thin plate, the weight becomes heavier and the thickness becomes thicker. Precision machining becomes difficult. In addition, when coining the breaking groove, which is the subject of the present invention, the occurrence of non-uniformity of the deflection of the lid and the occurrence of the constriction at the bottom of the breaking groove is unlikely to occur. It becomes unnecessary.

防爆弁：
図１、２において、本発明電池ケース蓋１は、その中央部に防爆弁２を備え、この防爆弁２の構造として、先ず、厚さ５０〜３００μｍの薄肉な平坦状凹部３が設けられている。平坦状凹部３の厚さが５０μｍ未満では、前記比較的高強度なアルミニウム合金薄板を蓋の素材として用いたとしても、蓋として要求される剛性や強度が不足する。一方、平坦状凹部３の厚さが３００μｍを超えると、後に加工される破断用凹溝４の厚さを十分薄くする加工が困難となり、電池ケースの内部圧力上昇に対して、電池ケースの破裂を防ぐため、破裂しない程度の内部圧力で開裂せず、防爆弁の起点となれない。また、前記した蓋の厚みと同じく、本発明の課題である、破断用凹溝のコイニング加工の際の、蓋のたわみの不均一性の発生や破断用凹溝底部のくびれの発生などが起きにくく、本発明の適用自体が不要となる。 Explosion-proof valve:
1 and 2, the battery case lid 1 of the present invention includes an explosion-proof valve 2 at the center thereof. As a structure of the explosion-proof valve 2, first, a thin flat concave portion 3 having a thickness of 50 to 300 μm is provided. Yes. If the thickness of the flat recess 3 is less than 50 μm, even if the relatively high strength aluminum alloy thin plate is used as a material for the lid, the rigidity and strength required for the lid are insufficient. On the other hand, when the thickness of the flat concave portion 3 exceeds 300 μm, it becomes difficult to sufficiently reduce the thickness of the breaking groove 4 to be processed later, and the battery case ruptures against an increase in the internal pressure of the battery case. In order to prevent this, it will not be cleaved at an internal pressure that will not rupture, and it will not be the starting point of the explosion-proof valve. In addition, similar to the thickness of the lid described above, the problem of the present invention, such as the occurrence of non-uniformity of the deflection of the lid and the occurrence of the constriction at the bottom of the groove for breaking, occurs when coining the breaking groove. It is difficult to apply the present invention.

この平坦状凹部３の平面視での形状は、必ずしも図１、２のような、プレス加工により成形しやすい、楕円状や楕円に類似の円形や多角形な形状にする必要はない。成形が可能であれば、他の平面視形状として、略四角形（略矩形）、真円形、円形に類似の多角形な形状に形成しても良い。また、この平坦状凹部３（防爆弁２）を設ける電池ケース蓋１の位置も、図１のように、その中央部とせずに、電池ケース蓋１の平面形状や面積、あるいは他の部品の取りつけ位置に応じて、端部側とするなど、適宜選択可能である。   The shape of the flat recess 3 in a plan view does not necessarily need to be an elliptical shape or a circular or polygonal shape similar to the elliptical shape, which is easy to be formed by pressing as shown in FIGS. As long as it can be molded, other shapes in plan view may be formed in a polygonal shape similar to a substantially square (substantially rectangular), a perfect circle, or a circle. Further, the position of the battery case lid 1 provided with the flat concave portion 3 (explosion-proof valve 2) is not the central portion as shown in FIG. 1, but the planar shape and area of the battery case lid 1 or other parts. Depending on the mounting position, it can be appropriately selected such as the end side.

平坦状凹部３の周縁部は、プレス加工により成形しやすい、元の蓋１の表面に向けて外方に広がる傾斜壁３aとされている。ただ、この壁３aの形状も、垂直や円弧状など、成形しやすい形状が適宜選択できる。   The peripheral edge portion of the flat concave portion 3 is an inclined wall 3a that spreads outward toward the surface of the original lid 1 that can be easily formed by pressing. However, the shape of the wall 3a can be appropriately selected from shapes that are easy to mold, such as vertical or arcuate.

破断用凹溝（主スコア）：
次に、図１、２では、この平坦状凹部３に、より薄肉な破断用凹溝（主スコア）４が前記コイニング加工により設けられている。この破断用凹溝４は、防爆弁としての主要な機能（起点）を果たす。すなわち、二次電池の外装である電池ケースの内部圧力上昇に対して、電池ケースの破裂を防ぐため、破裂しない程度の内部圧力で開裂する起点となって、内部圧力を開放する。 Groove for breaking (main score):
Next, in FIGS. 1 and 2, a thinner breaking groove (main score) 4 is provided in the flat recessed portion 3 by the coining process. This breaking groove 4 fulfills the main function (starting point) as an explosion-proof valve. That is, in order to prevent the battery case from rupturing against an increase in the internal pressure of the battery case that is the exterior of the secondary battery, the internal pressure is released as a starting point for the internal pressure that does not rupture.

これら破断用凹溝４の厚さ（加工後の底４ａの残存厚さ、図４のｔ３）は、１０〜１００μｍの範囲とする。破断用凹溝４の厚さが１０μｍ未満では、前記比較的高強度なアルミニウム合金薄板を蓋の素材として用いたとしても、蓋として要求される剛性や強度が不足する。一方、破断用凹溝４の厚さが１００μｍを越えると、電池ケースの内部圧力上昇に対して、電池ケースの破裂を防ぐため、破裂しない程度の内部圧力で開裂せず、防爆弁の起点となれない。   The thickness of the breaking groove 4 (the remaining thickness of the bottom 4a after processing, t3 in FIG. 4) is in the range of 10 to 100 μm. If the thickness of the breaking groove 4 is less than 10 μm, even if the relatively high strength aluminum alloy thin plate is used as a material for the lid, the rigidity and strength required for the lid are insufficient. On the other hand, when the thickness of the breaking groove 4 exceeds 100 μm, in order to prevent the battery case from rupturing against an increase in the internal pressure of the battery case, the internal pressure of the explosion-proof valve is not cleaved, can not become.

ここで、破断用凹溝４の平面視での形状は、図１では、平面視で楕円形の平坦状凹部３の形状に沿うかたちで、楕円形の環状に形成している。これに対して、図２の態様では、平面視で楕円形の平坦状凹部３の長さが最も長い中央部に沿うかたちで、直線状に形成している。このように、真円状、楕円状などの環状にするか、直線状あるいは曲線状にするか、また、破断用凹溝４を連続させるか、断続的に設けるかなどは、コイニング加工により形成が可能であれば、適宜選択できる。なお、破断用凹溝４は、本発明の課題のようにコイニング加工による形成が難しいため、互いに並列させて２本以上（複数本）設ける必要はなく、基本的に１本のみで良い。この破断用凹溝４を設ける平坦状凹部３内の位置は、図１のように、その中央部や長手方向に亘って延在するようにせずに、平坦状凹部３の平面形状や面積、あるいは取りつけ位置に応じて、適宜選択可能である。   Here, the shape of the breaking groove 4 in plan view is formed in an elliptical annular shape in FIG. 1 along the shape of the elliptical flat concave portion 3 in plan view. On the other hand, in the aspect of FIG. 2, the elliptical flat recessed part 3 is formed in a straight line along the longest central part in plan view. As described above, whether to form a perfect circle, an ellipse, or the like, or to form a straight line or a curve, or to continuously or intermittently provide the breaking groove 4 is formed by coining. Can be selected as appropriate. Since the breaking grooves 4 are difficult to be formed by coining as in the problem of the present invention, it is not necessary to provide two or more (a plurality) in parallel with each other, and basically only one groove is required. As shown in FIG. 1, the position in the flat concave portion 3 in which the breaking groove 4 is provided is not extended over the central portion or the longitudinal direction, but the planar shape and area of the flat concave portion 3, Or it can select suitably according to an attachment position.

図１、２では、この破断用凹溝４の断面が、この破断用凹溝４の肉厚を規定している平坦状底部４ａと、この底部４ａより平坦状凹部３の表面まで立ち上がる底部両側の傾斜両側壁４ｂ、４ｃとで形成される略くさび型（逆台形型）の断面形状をしている。このような略くさび型形状は、コイニング加工により形成しやすいが、成形が可能であれば、半円形、矩形などの、通常、凹溝の断面形状として公知な他の断面形状としても良い。   1 and 2, the cross-section of the breaking groove 4 has a flat bottom 4a that defines the thickness of the breaking groove 4, and both sides of the bottom rising from the bottom 4a to the surface of the flat depression 3. It has a substantially wedge-shaped (inverted trapezoidal) cross-sectional shape formed by the inclined side walls 4b and 4c. Such a substantially wedge-shaped shape can be easily formed by coining, but may be another cross-sectional shape that is generally known as a cross-sectional shape of a concave groove, such as a semicircular shape or a rectangular shape, as long as it can be formed.

成形補助用凹溝（副スコア）：
図１、２において、この破断用凹溝４に対して、この破断用凹溝４よりも厚肉だが、前記平坦状凹部３よりも薄肉な凹溝（副スコア）５が、破断用凹溝４の形成用凹溝として、破断用凹溝４に対して互いに間隔をあけて並列して、前記コイニング加工により設けられている。 Groove for auxiliary molding (sub-score):
1 and 2, the breaking groove 4 is thicker than the breaking groove 4 but thinner than the flat recess 3 (sub-score) 5. 4 forming recesses are provided by the coining process in parallel with the breaking recesses 4 at intervals.

この凹溝５は、破断用凹溝４をコイニング加工により形成（成形）する際の、成形を補助する役割を果たす。すなわち、この破断用凹溝と同時にコイニング加工により形成され、平坦状凹部３に、破断用凹溝４をコイニング加工する際に、形成する破断用凹溝４の裏側（破断用凹溝加工の底側）に、前記図６で示す「くびれ（へこみ）」が発生するのを防止する。   The concave groove 5 plays a role of assisting molding when the fracture concave groove 4 is formed (molded) by coining. That is, it is formed by coining at the same time as the breaking groove, and when the breaking groove 4 is coined into the flat recess 3, the back side of the breaking groove 4 to be formed (the bottom of the breaking groove processing bottom). The “neck” shown in FIG. 6 is prevented from occurring on the side).

電池ケース蓋の防爆弁の形成方法：
この凹溝５の機能を説明するために、先ず、図５を用いて、前記図１のタイプの環状の破断用凹溝４のコイニング加工方法、すなわち、本発明における電池ケース蓋の防爆弁の形成方法を説明する。 Formation method of explosion-proof valve for battery case lid:
In order to explain the function of the groove 5, first, referring to FIG. 5, the coining method of the annular breaking groove 4 of the type shown in FIG. 1, that is, the explosion-proof valve for the battery case lid in the present invention is used. A forming method will be described.

図５に断面図で示すコイニング加工装置において、先ず、蓋１の平坦状凹部３は、平板である素材アルミニウム合金板を、突起１１、１２を有さず、アルミニウム合金板と接触する底面側が平坦である金型１０（図示しない）によってコイニング加工により形成する。すなわち、蓋１を下方側から基台（剛体）１３で支持した上で、前記底面側が平坦である金型１０を蓋１の上方から下降あるいは基台１３を上昇させて、前記金型１０を蓋１表面に押圧し、平坦状凹部３を形成する。   In the coining apparatus shown in the cross-sectional view of FIG. 5, first, the flat recess 3 of the lid 1 is made of a flat aluminum alloy plate that does not have the projections 11 and 12 and the bottom surface that comes into contact with the aluminum alloy plate is flat. It is formed by coining with a mold 10 (not shown). That is, after the lid 1 is supported by the base (rigid body) 13 from the lower side, the mold 10 having the flat bottom surface is lowered from the upper side of the lid 1 or the base 13 is raised, and the mold 10 is moved. The flat recess 3 is formed by pressing against the surface of the lid 1.

これに次いで、蓋１の平坦状凹部３に、破断用凹溝４と成形補助用の凹溝５とを図５に示すコイニング加工装置にて形成する。図５おいて、蓋１の平坦状凹部３の上部に配置された金型１０には、平坦状凹部３と接触する底面側に、突起１１、１２が設けられている。この突起１１、１２は、平坦状凹部３側に点線で示す、形成したい環状の破断用凹溝４と、平坦状凹部３の幅方向の内側に配置された環状の凹溝５との形状、間隔、形成位置とに対応した形状、間隔、位置をしている。そして、平坦状凹部３上で環状（楕円状）に延在する破断用凹溝４と凹溝５に対応して、金型底面上に環状（楕円状）に延在するように設けられている。   Following this, in the flat concave portion 3 of the lid 1, a breaking groove 4 and a molding auxiliary groove 5 are formed by a coining apparatus shown in FIG. 5. In FIG. 5, the mold 10 disposed on the upper portion of the flat recess 3 of the lid 1 is provided with protrusions 11 and 12 on the bottom surface side in contact with the flat recess 3. The protrusions 11 and 12 are formed in a shape of an annular breaking groove 4 to be formed and an annular groove 5 disposed on the inner side in the width direction of the flat concave portion 3, as indicated by a dotted line on the flat concave portion 3 side, The shape, interval, and position correspond to the interval and formation position. And it is provided so as to extend annularly (elliptical) on the mold bottom surface corresponding to the concave groove 4 and the concave groove 5 extending annularly (elliptical) on the flat concave portion 3. Yes.

なお、突起１１、１２は、当然ながら形成したい凹溝の断面形状や長手方向の形状に対応させるものであり、前記図２のタイプの直線状の破断用凹溝４、５をコイニング加工する場合には、突起１１、１２も、これに応じて直線状となる。ちなみに、環状の凹溝５の形成用の突起１２の存在を除けば、前記図６の従来公知の破断用凹溝４のコイニング加工方法と、装置的にも操作的にも同じである。   The protrusions 11 and 12 naturally correspond to the cross-sectional shape and longitudinal shape of the groove to be formed, and when the linear breaking grooves 4 and 5 of the type shown in FIG. 2 are coined. Accordingly, the projections 11 and 12 are also linearly formed accordingly. By the way, except for the presence of the projection 12 for forming the annular groove 5, it is the same as the conventionally known coining method for the breaking groove 4 of FIG. 6 in terms of apparatus and operation.

凹溝形成用の突起１１は平坦状凹部の幅方向の外側の破断用凹溝４の形成（刻印、圧刻）用として、厚さ１０〜１００μｍの肉厚である破断用凹溝に対応した高さを有し、断面形状が前記くさび型形状とをしている。また、凹溝形成用の突起１２は平坦状凹部の幅方向の内側の凹溝５の形成（刻印、圧刻）用として、前記破断用凹溝４よりも厚肉だが、前記平坦状凹部３よりも薄肉な凹溝に対応する高さを有し、断面形状が前記くさび型をしている。   The protrusion 11 for forming the groove corresponds to the groove for breaking having a thickness of 10 to 100 μm for forming (engraved or stamped) the groove for breaking 4 on the outer side in the width direction of the flat recess. It has a height and the cross-sectional shape is the wedge shape. Further, the concave groove forming projection 12 is thicker than the breaking concave groove 4 for forming the concave groove 5 on the inner side in the width direction of the flat concave portion (engraving, stamping), but the flat concave portion 3 It has a height corresponding to the thinner groove, and the cross-sectional shape is the wedge shape.

これら凹溝形成に際しては、蓋１（平坦状凹部３）を下方側からを基台（剛体）１３で支持した上で、金型１０を下降あるいは基台１３を上昇させて、前記金型１０の突起１１、１２を平坦状凹部３表面に押圧していく。そして、破断用凹溝４と互いに間隔をあけて並列した凹溝５とを同時にコイニング加工により形成（刻印、圧刻）していく。   In forming these concave grooves, the lid 10 (flat concave portion 3) is supported from below by a base (rigid body) 13 and then the mold 10 is lowered or the base 13 is raised to move the mold 10 The projections 11 and 12 are pressed against the surface of the flat recess 3. Then, the breaking grooves 4 and the recessed grooves 5 arranged in parallel with a gap are simultaneously formed (engraved or stamped) by coining.

成形補助用凹溝５の機能：
破断用凹溝４と互いに間隔をあけて並列した凹溝５とを同時にコイニング加工することによって、コイニング加工時に、前記図６で示した特にたわみやすい平坦状凹部３の幅方向の内側の部分が凹溝５のコイニング加工によって、金型１０（突起１２）と基台１３とで挟持され、拘束されることとなる。これによって、前記平坦状凹部３の「たわみ」が抑制され、金型の突起の下降（押し付け）にて左右に押し分けられるアルミニウム合金材料の移動の仕方が均一化される。これによって、平坦状凹部３や破断用凹溝４の残厚の精度や形状精度の確保が図れる。 The function of the concave groove 5 for forming support:
By simultaneously coining the breaking grooves 4 for breaking and the recessed grooves 5 arranged in parallel with each other at the same time, the inner portion in the width direction of the flat concave portion 3 shown in FIG. By the coining process of the concave groove 5, the mold 10 (protrusion 12) and the base 13 are sandwiched and restrained. As a result, the “deflection” of the flat concave portion 3 is suppressed, and the manner of movement of the aluminum alloy material that is pushed right and left by the lowering (pressing) of the protrusions of the mold is made uniform. Thereby, it is possible to ensure the accuracy of the remaining thickness and the shape accuracy of the flat recess 3 and the breaking groove 4.

このような機能を発揮する必須の条件として、先ず、破断用凹溝４に対して、この破断用凹溝４よりも厚肉だが前記平坦状凹部よりも薄肉とする。この破断用凹溝４よりも薄肉であり、破断用凹溝４と互いに間隔をあけて並列した凹溝５とを同時にコイニング加工すると、コイニング加工時に凹溝５の内側の平坦状の凹部３のたわみが生じ，凹溝５の裏側にくびれが生じてしまう。また、凹溝５が破断用凹溝４よりも先に内圧によって破壊されることとなる。そして、前記平坦状凹部と同じ厚さでは、そもそも凹溝５自体が形成できない。   As an indispensable condition for exhibiting such a function, first, the breaking groove 4 is thicker than the breaking groove 4 but thinner than the flat recess. When the breaking groove 4 is thinner than the breaking groove 4 and is coined at the same time with the breaking groove 5 parallel to the breaking groove 4, the flat recess 3 on the inner side of the groove 5 is formed during the coining process. Deflection occurs and constriction occurs on the back side of the groove 5. Further, the concave groove 5 is broken by the internal pressure before the breaking concave groove 4. And the groove 5 itself cannot be formed in the first place with the same thickness as the flat recess.

また、凹溝５を破断用凹溝４に対して互いに間隔をあけて並列させていないと、破断用凹溝と同時にコイニング加工する際に、凹溝５が、これら凹溝周辺の前記平坦状凹部３を拘束する機能を果たせない。この互いの間隔も、互いに近接させないで離れすぎると、凹溝５がこれら凹溝周辺の平坦状凹部３を拘束する機能が弱くなる。   Further, if the concave grooves 5 are not parallel to the breaking concave grooves 4 at a distance from each other, when the coining is performed at the same time as the breaking concave grooves, the concave grooves 5 are formed in the flat shape around the concave grooves. The function of restraining the recess 3 cannot be performed. If the distance between the grooves is too close without being close to each other, the function of the concave grooves 5 restraining the flat concave portions 3 around the concave grooves becomes weak.

更に、破断用凹溝４と同時に、コイニング加工により凹溝５を形成することをせず、コイニング加工による凹溝５側の形成に、破断用凹溝４の加工開始に対する「時間的な遅れ」が生じるほど、あるいは破断用凹溝４の加工開始前に先に加工してしまうような「時間的なズレ」が大きいほど、凹溝５がこれら凹溝周辺の平坦状凹部３を拘束する機能が弱くなる。   Further, the concave groove 5 is not formed by coining at the same time as the breaking groove 4, but “time delay” with respect to the start of machining of the breaking groove 4 in the formation of the concave groove 5 side by coining. The function of the groove 5 restraining the flat concave portion 3 around the concave groove is larger as the time difference is generated or the “temporal shift” that is processed before the breaking concave groove 4 is started is larger. Becomes weaker.

本発明において、成形補助用の凹溝５は、このように破断用凹溝４をコイニング加工により形成する際の、成形を補助する機能を果たすべく設けられる。したがって、前記した特許文献８のように、蓋体の一部に平面視で円形の薄肉部を設け、ここに薄肉の環状凹溝（破断用凹溝）を二つ、間隔をあけて並列させて設けて、これらの互いの厚みを変えて、高圧用安全弁と低圧用安全弁とし、防爆弁）としている方式とは次のように区別される。   In the present invention, the molding assisting concave groove 5 is provided so as to fulfill the function of assisting molding when the fracture concave groove 4 is formed by coining. Therefore, as in the above-mentioned Patent Document 8, a circular thin portion is provided in a part of the lid body in plan view, and two thin annular concave grooves (breaking concave grooves) are arranged in parallel at a distance from each other. These are differentiated from the system in which the thickness of each of these is changed to be a high pressure safety valve and a low pressure safety valve (explosion proof valve) as follows.

すなわち、特許文献８では、蓋自体や平坦状凹部の厚みも不明であり、これら環状凹溝の肉厚をｄ１、ｄ２として示しているものの、数値の記載がなく、本発明のような薄さであるのか不明である。また、蓋の材質についても記載がなく、本発明のようなアルミニウム合金か不明である。更に、特許文献８では、円形の内側の方の環状凹溝をより薄肉、外側の方の環状凹溝をより厚肉としている点も異なる。これに対して、本発明では、逆に、図１のように、より厚肉な環状凹溝５の方を、破断用環状凹溝４よりも、平面視で平坦状凹部３の幅方向の内側（内方）に形成する。これも凹溝を図１のような環状とする場合に、凹溝５が前記図６で示した特にたわみやすい平坦状凹部３の幅方向の内側の部分を拘束する機能を強めるためである。特許文献８のように、より厚肉な環状凹溝の方を、破断用凹溝４よりも、平面視で平坦状凹部３の外側（外方）に形成した場合には、この機能が弱まってしまい、前記コイニング加工における、平坦状凹部３や破断用凹溝４の残厚の精度や形状精度の確保が図れなくなる。   That is, in Patent Document 8, the thickness of the lid itself and the flat concave portion is unknown, and although the thickness of these annular concave grooves is indicated as d1 and d2, there is no description of the numerical value, and the thickness as in the present invention is not shown. It is unknown whether it is. Moreover, there is no description about the material of a lid | cover, and it is unknown whether it is an aluminum alloy like this invention. Furthermore, Patent Document 8 is different in that the circular groove on the inner side of the circle is thinner and the ring groove on the outer side is thicker. In contrast, in the present invention, on the contrary, as shown in FIG. 1, the thicker annular groove 5 is wider than the breaking annular groove 4 in the width direction of the flat recess 3 in plan view. Form inside (inward). This is also to enhance the function of restraining the inner portion in the width direction of the flat concave portion 3 that is particularly flexible as shown in FIG. 6 when the concave groove has an annular shape as shown in FIG. When the thicker annular groove is formed on the outer side (outside) of the flat recess 3 in plan view than the breaking groove 4 as in Patent Document 8, this function is weakened. As a result, it is impossible to ensure the accuracy and shape accuracy of the remaining thickness of the flat recess 3 and the breaking recess 4 in the coining process.

このように、破断用凹溝４と破断用凹溝の形成用凹溝５とを、平面視で、互いに間隔をあけて並列された略環状に各々形成する図１のような場合には、より厚肉な環状凹溝５の方を、より薄肉な破断用環状凹溝４よりも、平面視で平坦状凹部３の幅方向の内側（内方）にコイニング加工により形成する。これは、前記した通り、凹溝５がこれら凹溝周辺の前記平坦状凹部３を拘束する機能を強めるためであり、破断用凹溝の形成用凹溝５の方を、破断用凹溝４よりも、平面視で平坦状凹部３の外側（外方）に形成した場合にはこの機能が弱まる。   In this way, in the case of FIG. 1 in which the breaking groove 4 and the breaking groove 5 for forming the breaking groove are each formed in a substantially annular shape in parallel with each other in a plan view, The thicker annular groove 5 is formed by coining on the inner side (inward) in the width direction of the flat recess 3 in plan view than the thinner annular groove 4 for breaking. This is because, as described above, the concave grooves 5 strengthen the function of restraining the flat concave portions 3 around the concave grooves. The concave grooves 5 for forming the concave grooves for breaking are used as the concave grooves 4 for breaking. In contrast, this function is weakened when formed on the outside (outside) of the flat recess 3 in plan view.

一方、図２では、破断用凹溝の形成用凹溝５、６を、直線状の破断用凹溝４に対して、その両側に破断用凹溝４を挟む形で２本、コイニング加工により、直線状に互いに間隔をあけて並列して設けている。これも、凹溝５がこれら凹溝周辺の前記平坦状凹部３を拘束する機能を強めるためである。これに対して、破断用凹溝の形成用凹溝５か６のいずれかを、直線状の破断用凹溝４に対して、そのいずれか片側に１本だけ、コイニング加工により、直線状に互いに間隔をあけて並列して設けても良い。このような場合は、直線状の破断用凹溝４に対して、いずれの側にでも、破断用凹溝の形成用凹溝５か６を設けても良い。   On the other hand, in FIG. 2, two concave grooves 5, 6 for forming the fracture grooves are formed by coining, with the fracture grooves 4 on both sides of the straight fracture grooves 4. These are provided in parallel and spaced apart from each other in a straight line. This is also because the groove 5 strengthens the function of restraining the flat recess 3 around the groove. On the other hand, either one of the grooves 5 or 6 for forming the breaking groove 5 is linearly formed by coining with respect to the straight breaking groove 4 on either side. You may provide in parallel mutually spaced apart. In such a case, the breaking groove 5 or 6 for forming the breaking groove may be provided on either side of the linear breaking groove 4.

電池ケース蓋の全体形状：
図３は前記図１のタイプの、実際に設計、製造される本発明電池ケース蓋１の、矩形な平板状の直方体からなる全体形状例を、上側に平面図、下側に側面図で各々示している。 Overall shape of battery case lid:
FIG. 3 shows an example of the overall shape of the battery case cover 1 of the present invention actually designed and manufactured of the type shown in FIG. 1, which is a rectangular flat rectangular parallelepiped, with a plan view on the upper side and a side view on the lower side. Show.

電池ケース蓋１の大きさ、形状、面積などは、通常のリチウムイオン二次電池などの仕様（電池ケース本体の仕様）に従う。なお、この電池ケース蓋１が装着される電池ケース本体や、電池ケース蓋１に通常装着されるべき、外部正極、電解液の注入口やカバーなどの他の必要部品の表示も省略している。この図３において、１ａ、１ｂは蓋１の幅方向の両側面、１ｃは底面、１ｄ、１ｄは蓋１の長手方向の両端部である。   The size, shape, area, and the like of the battery case lid 1 conform to specifications (specifications of the battery case main body) such as a normal lithium ion secondary battery. In addition, the display of the battery case main body to which the battery case lid 1 is attached, and other necessary parts such as the external positive electrode, the electrolyte inlet, and the cover that are normally attached to the battery case lid 1 are also omitted. . In FIG. 3, 1 a and 1 b are both side surfaces in the width direction of the lid 1, 1 c is a bottom surface, and 1 d and 1 d are both ends in the longitudinal direction of the lid 1.

この図３の電池ケース蓋１における防爆弁構成は前記図１と同じであり、平板状の蓋１の平坦状凹部３の中央部に防爆弁２を備え、この防爆弁２の構造として薄肉な平坦状凹部３が設けられている。そして、この平坦状凹部３により薄肉な破断用環状凹溝４が前記コイニング加工により設けられている。また、成形補助用環状凹溝５の方を、破断用凹溝４よりも、平面視で平坦状凹部３の内側（内方）に、コイニング加工により、平面視で互いに間隔をあけて並列された楕円形状に各々形成している。   The structure of the explosion-proof valve in the battery case lid 1 in FIG. 3 is the same as that in FIG. 1, and the explosion-proof valve 2 is provided at the center of the flat recess 3 of the flat lid 1. A flat recess 3 is provided. The flat recess 3 is provided with a thin annular groove 4 for breaking by coining. Further, the annular groove for auxiliary molding 5 is arranged in parallel to the inner side (inward) of the flat concave portion 3 in plan view with a gap from each other in plan view by coining, as compared with the breaking groove 4. Each has an elliptical shape.

ここで、図示しない電池ケース本体は、図３の蓋１に対応する形状をしており、通常は、正面および背面が側面および上下面に比べて広面である偏平形の略直方体（箱体）である。材質は鋼製やＳＵＳ製でも良いが、電池ケース蓋１と同じアルミニウム合金板で形成されることが好ましい。また、大きさは通常のリチウムイオン二次電池などの仕様に従うものとする。また、電池ケース本体の板厚は二次電池の仕様や加工方法等によるものであり、特に限定されないが、好ましくは、底面０．５〜１．５ｍｍ、正背面および側面０．５〜１．２ｍｍである。電池ケース本体の成形方法としては、板厚０．５〜１．５ｍｍのアルミニウム合金板を、例えば絞り加工等の公知の方法により成形することが挙げられる。   Here, the battery case main body (not shown) has a shape corresponding to the lid 1 of FIG. 3, and is generally a flat, substantially rectangular parallelepiped (box) whose front and back are wider than the side and top and bottom. It is. The material may be steel or SUS, but is preferably formed of the same aluminum alloy plate as the battery case lid 1. Also, the size conforms to the specifications of a normal lithium ion secondary battery. The plate thickness of the battery case body depends on the specifications and processing method of the secondary battery, and is not particularly limited, but is preferably 0.5 to 1.5 mm on the bottom surface, 0.5 to 1.5 mm on the front and side surfaces, and 0.5 to 1. 2 mm. Examples of the method for forming the battery case body include forming an aluminum alloy plate having a thickness of 0.5 to 1.5 mm by a known method such as drawing.

電池ケース蓋や本体電池ケースのアルミニウム合金板としては、純アルミニウムである１０００系合金か、３０００（Ａｌ−Ｍｎ）系合金の中でも高強度なアルミニウム合金が加工性および耐食性の面から好ましい。ただ、使用条件や成形条件によっては、より高強度な５０００系や６０００系アルミニウム合金を用いても良い。また、適度な内部圧力で開裂させ、また成形も可能とするために、その材料強度は０．２％耐力で４０〜１４０ＭＰａの範囲が好ましい。   As the aluminum alloy plate of the battery case lid or the main battery case, a high-strength aluminum alloy is preferable from the viewpoint of workability and corrosion resistance among 1000 series alloys that are pure aluminum or 3000 (Al-Mn) series alloys. However, higher-strength 5000 series or 6000 series aluminum alloys may be used depending on use conditions and molding conditions. In addition, in order to allow the material to be cleaved with an appropriate internal pressure and to be molded, the material strength is preferably in the range of 40 to 140 MPa with a 0.2% proof stress.

図４は、前記図３の下側の側面図に○印のＡで囲んだ防爆弁２の部分を断面図で拡大して示している。そして、下側に、前記断面図の○印のＢで囲んだ破断用凹溝４と破断用凹溝の形成用凹溝５の部分を断面図で拡大して示している。   FIG. 4 is an enlarged cross-sectional view of a portion of the explosion-proof valve 2 surrounded by a circle A in the lower side view of FIG. In the lower side, the fractured groove 4 and the fractured groove 5 for forming the fractured groove 5 surrounded by B in the cross sectional view are enlarged and shown in a sectional view.

図４の電池ケース蓋１は、厚さ（板厚）ｔ１が１．１ｍｍ、平坦状凹部３の厚さ（板厚）ｔ２が１１０μｍである。また、破断用凹溝（主スコア）４の厚さである、コイニング加工後の底４ａの残存厚さｔ３が２０μｍ、成形補助用の凹溝５（副スコア）のコイニング加工後の底５ａの残存厚さｔ４が４０μｍである。更に、破断用凹溝（主スコア）４のくさび型断面における平坦な底４ａの横方向の幅ｗ１が５０μｍ、平坦状凹部３側（上側）の横方向の幅ｗ２が１１０μｍである。また、成形補助用の凹溝５（副スコア）のくさび型断面における平坦な底５ａの横方向の幅ｗ３が１０μｍ、平坦状凹部３側（上側）の横方向の幅ｗ４が１００μｍである。   4 has a thickness (plate thickness) t1 of 1.1 mm, and the flat recess 3 has a thickness (plate thickness) t2 of 110 μm. Further, the remaining thickness t3 of the bottom 4a after coining, which is the thickness of the breaking groove (main score) 4, is 20 μm, and the bottom 5a of the bottom 5a after coining of the concave groove 5 (sub-score) for forming assist The remaining thickness t4 is 40 μm. Further, the lateral width w1 of the flat bottom 4a in the wedge-shaped cross section of the breaking groove (main score) 4 is 50 μm, and the lateral width w2 on the flat concave portion 3 side (upper side) is 110 μm. Further, the lateral width w3 of the flat bottom 5a in the wedge-shaped cross section of the concave groove 5 (sub-score) for forming is 10 μm, and the lateral width w4 on the flat concave 3 side (upper side) is 100 μm.

以上、本発明は、薄肉なアルミニウム合金製蓋の破断用凹溝を精度よく加工することができ、破裂する前に確実に開裂する防爆機構を備える電池ケースの蓋の防爆弁の形成方法を提供できる。このため、リチウムイオン二次電池などに好適に使用することができる。 Above, the present invention can be processed accurately breaking groove of thin aluminum alloy lid, the method of forming the explosion-proof valve lid batteries case Ru equipped with explosion-proof mechanism to reliably cleaved prior to rupture Can provide. For this reason, it can be suitably used for a lithium ion secondary battery or the like.

１：電池ケース蓋、２：防爆弁、３：薄肉平坦部、４：破断用凹溝、５、６：成形補助用凹溝、１０：金型、１１、１２：突起、１３：基台 1: battery case cover, 2: explosion-proof valve, 3: thin flat portion, 4: breaking groove, 5, 6: molding assisting groove, 10: mold, 11, 12: protrusion, 13: base

Claims (4)

電池ケース蓋の防爆弁の形成方法であって、厚さ０．５〜２ｍｍのアルミニウム合金板からなる前記電池ケース蓋のコイニング加工によって、この電池ケース蓋に厚さ５０〜３００μｍの薄肉な平坦状凹部を形成した後、この平坦状凹部に厚さ１０〜１００μｍのより薄肉な破断用凹溝を更にコイニング加工により形成するに際し、この破断用凹溝に対して、この破断用凹溝よりも厚肉だが前記平坦状凹部よりも薄肉な凹溝を、この破断用凹溝に対して互いに間隔をあけて並列させて、この破断用凹溝と同時にコイニング加工により形成することを特徴とする電池ケース蓋の防爆弁の形成方法。   A method for forming an explosion-proof valve for a battery case lid, wherein the battery case lid is thinly flattened by a thickness of 50 to 300 μm by coining the battery case lid made of an aluminum alloy plate having a thickness of 0.5 to 2 mm. After forming the recess, when a thinner breaking groove having a thickness of 10 to 100 μm is further formed by coining in the flat recess, the breaking groove is thicker than the breaking groove. A battery case characterized by being formed by coining processing at the same time as the breaking groove, with a groove, which is thin but thinner than the flat recess, arranged in parallel with the breaking groove at a distance from each other A method of forming an explosion-proof valve for a lid. 前記破断用凹溝が、この破断用凹溝の肉厚を規定している平坦状底部と、この底部より前記平坦状凹部表面まで立ち上がる傾斜両側壁とで形成される略くさび型の断面形状をしている請求項１に記載の電池ケース蓋の防爆弁の形成方法。 The breaking groove has a substantially wedge-shaped cross section formed by a flat bottom that defines the thickness of the breaking groove and inclined side walls that rise from the bottom to the flat depression surface. The method for forming an explosion-proof valve for a battery case cover according to claim 1. 前記破断用凹溝と前記破断用凹溝の形成用凹溝とが、平面視で、互いに間隔をあけて並列された略環状に各々形成され、前記破断用凹溝の形成用凹溝の方が前記破断用凹溝よりも平面視で前記平坦状凹部の幅方向の内側に形成されている請求項１または２に記載の電池ケース蓋の防爆弁の形成方法。 The groove for forming the groove for breaking and the groove for forming the groove for breaking are each formed in a substantially annular shape parallel to each other with a space in plan view. 3. The method for forming an explosion-proof valve for a battery case cover according to claim 1, wherein the explosion-proof valve is formed on the inner side in the width direction of the flat recess in plan view than the breaking recess. 前記破断用凹溝と前記破断用凹溝の形成用凹溝とが、平面視で、互いに間隔をあけて並列された略直線状に各々形成されている請求項１または２に記載の電池ケース蓋の防爆弁の形成方法。 3. The battery case according to claim 1, wherein the breaking groove and the breaking groove forming groove are each formed in a substantially straight line parallel to each other in a plan view. A method of forming an explosion-proof valve for a lid.
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