JP4107468B2

JP4107468B2 - battery

Info

Publication number: JP4107468B2
Application number: JP2000370993A
Authority: JP
Inventors: 亜矢小林; 知徳岸本; 伊藤　　隆
Original assignee: GS Yuasa Corp
Current assignee: GS Yuasa Corp
Priority date: 2000-12-06
Filing date: 2000-12-06
Publication date: 2008-06-25
Anticipated expiration: 2020-12-06
Also published as: JP2002175792A

Description

【０００１】
【発明の属する技術分野】
本発明は、タブレス方式の極板群に板状の集電端子を溶接して成る電池に関するもので、低価格で容積効率および電気的特性の信頼性に優れた電池を提供せんとするものである。
【０００２】
【従来の技術】
近年、環境に優しいハイブリッド電気自動車や電気自動車用の実用化が進行している。更なる普及のための重要課題として、動力源である電池に関して価格低減、走行距離を伸ばすためのエネルギー密度の向上等が採り挙げられている。また、これらの用途には複数の単電池を集合した組電池が用いられるため、単電池の性能について信頼性の向上が求められている。
【０００３】
電池のコストおよび容積、重量の低減および電気的性能の信頼性向上に関して、電池の構造および部品、とりわけ集電に関係する構造および部品の改良は重要である。同改良に関して既に幾つかの提案が成されている。主な事項を挙げると、第１は極板の基板端部を極板群の一面に突出させ、該基板端部と板状集電端子を抵抗溶接したタブレス方式の集電構造の採用である。本構造は極板群に複数の集電用のタブやリードを必要としないので、極板群と端子間の距離が縮まり、両者の間に生ずる無駄な空間が占める容積を低減できる。また極板群に集電体を溶接する工程の能率向上にも有効である。
【０００４】
第２は集電端子の改良である。板状集電端子の溶接箇所の間に切り欠き部（スリット）を備えたこと、およびスリット縁部を集電端子の平面に対して垂直になるように折り曲げ、該折り曲げ部（以下櫛歯と記述する）の端部を極板の基板端部に当接して溶接する。前記スリットを設けたことによって溶接時の無効電流を抑制でき、溶接の信頼性が高めることができる。また、前記櫛歯も基板端部と集電端子の溶接の信頼性を高めるのに有効である。
【０００５】
しかし、従来のように板状集電端子を部分的に折り曲げて櫛歯を形成する構造では、加工が煩雑で集電端子が高価になる欠点があった。
【０００６】
また、櫛歯形成工程において集電端子に変形を生じる虞があり、櫛歯と極板の基板端部との間に当接の不十分が生じるために溶接不良を引き起こす場合があった。さらに、集電端子に変形を生じていない場合においても、集電端子と極板との溶接不良を確実に無くすことができなかった。
【０００７】
【発明が解決しようとする課題】
本発明は、従来電池の欠点に鑑み、集電端子の構造を改良することによって電池の価格低減を図り、電気的性能面での信頼性を向上するものである。
【０００８】
【課題を解決するための手段】
本発明は、曲げ加工により櫛歯を設けた櫛歯部品を集電端子本体に溶接する工程と、正極板、セパレータおよび負極板を積層した極板群の一面から突出した少なくとも一方の極板の基板端部に、前記集電端子本体に溶接された前記櫛歯部品の前記櫛歯を溶接する工程とを含むことを特徴とする電池の製造方法である。
【０００９】
また、本発明は板状集電端子の外部端子との接合箇所に抵抗溶接用のプロジェクションを設けることが好ましい。
【００１０】
【発明の実施の形態】
図３および図４は本発明に係る電池の正極集電端子１の１形態を示す図である（負極集電端子は、形状、材質共に正極集電端子と同じものを適用できるので、記述を省略する）。図３は集電端子の側面図、図４は櫛歯を溶接によって取り付けた面の正面図である。図３に示す如く、集電端子は板状の集電端子本体１と櫛歯部品３の２つの部品で構成される。櫛歯部品３は対向する２辺を垂直に折り曲げ、平面部を集電端子本体１の面に溶接している。
【００１１】
従来の集電端子の場合、櫛歯を設けるために集電端子本体に先ずスリットを設け、そのエッジ部分を折り曲げなければならず、製造工程が煩雑であった。また、スリットのエッジ部分の折り曲げ工程で、集電端子本体に変形が生じるか虞があった。本発明に係る電池の集電端子は、予め両辺を折り曲げることにより櫛歯を形成した櫛歯部品３を板状集電端子２に溶接するだけの簡単な工程で済み、その分安価にできる。
【００１２】
本発明に係る集電端子の櫛歯は、肉厚が０．０５〜０．１ｍｍ、高さが０．３〜０．７ｍｍで、集電端子本体の肉厚は０．３〜０．８ｍｍであることが望ましい。
【００１３】
前記櫛歯の肉厚は機械的強度およびそこを流れる電流の大きさに見合うように設定される。櫛歯の肉厚が小さくなると極板の基板端部との溶接箇所の接合面積が小さくなるため、該箇所の電気抵抗が大きくなる。櫛歯の肉厚が０．０５ｍｍを下回ると、前記溶接箇所の電気抵抗が大きくなることにより電池の高率放電性能の低下を招く。
【００１４】
また、櫛歯の肉厚が大きいと、該櫛歯と基板端部とを抵抗溶接によって溶接することが困難になる。櫛歯の肉厚が０．１ｍｍを超えると、確実に溶接することができず、一部の極板の基板端部との溶接不良を招く。該溶接不良は、所定の放電性能が得られない等の電気的性能面での信頼性の低下に繋がる。従って、櫛歯の肉厚は前記の範囲内で、櫛歯の数および流れる電流の大きさを考慮して設定されることが望ましい。
【００１５】
櫛歯の高さは、櫛歯の肉厚同様櫛歯と基板端部との溶接箇所の接合面積に影響する。すなわち、高さが低いと接合面積が小さくなる。櫛歯の高さが０．３ｍｍを下回ると接合面積が小さく、溶接箇所の電気抵抗が高くなるため、電池の高率放電性能の低下を招く。また櫛歯の高さが高いと、溶接の過程で溶融しない櫛歯が残る。このため、基板端部と集電端子本体の間に隙間が生じ、その分無駄な空間となるため、電池の容積効率の低下を招く。従って櫛歯の高さは前記の如く０．３〜０．７ｍｍの範囲にあることが望ましい。
【００１６】
集電端子本体２の肉厚は０．３〜０．８ｍｍ、更には０．４〜０．６ｍｍであることが望ましい。
【００１７】
電池内を流れる全ての電流が集電端子本体２を流れる。また集電端子本体２は極板群を構成する全ての正極板または負極板を束ねる役目を担っている。集電端子本体の肉厚が薄いと、電気抵抗がたかくなり、また機械的強度が低下する。集電端子本体の肉厚が０．３ｍｍを下回ると電気抵抗が高いため、電池の高率放電性能の低下を招く。また、集電端子の機械的強度の不足により、全極板を束ねることが困難であり、さらに抵抗溶接過程で加わる荷重に耐えられず、変形する虞も生じる。従って、集電端子の肉厚は０．３ｍｍ以上、更には０．４ｍｍ以上とすることが望ましい。
【００１８】
集電端子本体の肉厚が大きくなると、集電端子と極板基板端部を溶接する時の無効電流が増すため溶接が困難になり、溶接の信頼性が低下する。また集電端子の重量が大きくなるため、電池の重量効率の低下を招く。集電端子本体の肉厚は、流れる電流の大きさ、極板の枚数、集電端子の通電経路の長さ等を考慮した上で０．８ｍｍ以下、更には０．６ｍｍ以下とすることが望ましい。
【００１９】
本発明によれば集電端子の加工を容易にできるので、価格の低減を図ることができる。さらに、本発名によれば集電端子本体と櫛歯を別部品としたことによって、それぞれの肉厚を個別に最適な値に設定できる。このことは、集電端子本体の一部を折り曲げて櫛歯を形成していた従来の集電端子では成し得なかったことである。また集電端子本体と別部品である櫛歯部品に予め曲げ加工を施すので、集電端子本体に変形を生じる虞が無い。
【００２０】
図３および図４に示した如く、本発明に係る集電端子本体１の外部端子との接合箇所に抵抗溶接用プロジェクション６を設ける。集電端子本体および外部端子側の接合部品共に肉厚が大きいため抵抗溶接によって接合することが困難であるが、該プロジェクションの配置によって集電端子と外部端子の接合が確実になるため、電池の電気的性能の信頼性向上に繋がる。
【００２１】
本発明が適用される電池の種類は特に限定されるものではない。例えばニッケルカドミウム電池やニッケル水素電池等のアルカリ蓄電池、リチウム二次電池等に適用できる。また、電池および極板群の形状も特に限定されるものでは無い。角形および円筒形電池、積層式極板群を備える電池、捲回式極板群を備える電池いずれにも適用できる。
【００２２】
（実施例）
以下に積層式極板群を備えた角形のニッケル水素電池を例に採って本発明の詳細を説明する。図１は本実施例電池に係る集電端子を取り付けた極板群の斜視図である。図２はどう極板群を極板側から見た図である。
【００２３】
幅が３０ｍｍ、高さが１２０ｍｍ、容量密度５００ｍＡｈ／ｃｃのペースト式ニッケル正極板（図２では隠れて見えない）１２枚と、幅が３０ｍｍ、高さが１２０ｍｍで厚さが０．３ｍｍの鋼板式水素吸蔵合金負極板４ａを１３枚、厚さ０．１５ｍｍのポリプロピレン不織布製のセパレータ４ｂを積層して極板群４とした。
【００２４】
正極板は厚さ０．５ｍｍのニッケル製多孔質基板に水酸化ニッケル粉末を主成分とする合剤を充填したものであり、長辺の１辺に幅２ｍｍの帯状の未充填部分を設けた。該未充填部分に厚さ０．３ｍｍのニッケル板を溶接した。
【００２５】
負極板は厚さ０．０６ｍｍの鋼板製基板上に水素吸蔵合金を主成分とする合剤を塗布したもので、長辺の１辺に幅２ｍｍの帯状の未塗工部分を設けた。正極板と負極板は幅方向に２．５ｍｍずらして積層し、極板群の１方の側面に正極板の未充填部分にニッケル板を溶接した基板端部を、対向する他方の側面に負極板の未塗工部分から成る基板端部を突出させた。
【００２６】
前記極板群を固定し、極板群の側面に突出させた正極板基板端部、負極板基板端部それぞれに、正極集電端子１および負極集電端子２の櫛歯３を当接し、抵抗溶接により溶接した。使用した集電端子は、厚さ０．４ｍｍのニッケル製集電端子本体２に厚さ０．０７ｍｍ、歯の高さが０．５ｍｍ、歯間距離が１４ｍｍの櫛歯部品３を溶接したものである。尚、溶接時の無効電流を低減し、溶接の信頼性を高めるため、集電端子本体２および櫛歯部品３の櫛歯と櫛歯の間に直径６ｍｍφの透孔５を設けた。
【００２７】
尚、図２では櫛歯３の存在を明示するために、やむを得ず極板の基板端部と正極集電端子１および負極集電端子２との間に隙間を開けて描いている。しかし実際には溶接によって櫛歯３が溶融するので、基板端部と集電端子本体の間には殆ど隙間を生じない。
【００２８】
該極板群を電槽に挿入し、集電端子１および２に設けたプロジェクション６および７（正極集電端子１に設けたプロジェクション６は、陰になって見えない）と外部端子のリードを溶接し、接合した。ＫＯＨの水溶液を主成分とする電解液を所定量注液し、常法により気密に密閉して電池とした。作製した電池は、高さが１３０ｍｍ、幅が３６ｍｍ、厚さが２０ｍｍで公称容量が１０Ａｈである。
【００２９】
（比較例）
前記櫛歯、プロジェクション、および透孔を設けない、厚さ０．４ｍｍのニッケル製集電端子を適用した以外は実施例と同一の条件で電池を作製した。
【００３０】
（放電性能評価）
作製した実施例電池と比較例電池を活性化した後、電流５Ａで２．５時間充電した。その後電流１５０Ａ（放電率１５Ｃ）、終止電圧０．８Ｖの試験条件で放電試験に供した。
その結果を図５に示す。
【００３１】
図５に示したように、本発明の実施例電池は、比較例電池と比べ放電電圧、放電容量共に高い性能を示した。
【００３２】
図６は実施例電池と比較例電池の極板群を構成する１２枚の全正極板と正極集電端子の間の電気抵抗を測定した結果を示す図である。特に比較例電池のＮｏ.１、Ｎｏ.８、Ｎｏ.１２の極板の抵抗値が高く、溶接不良が起きていることを示唆している。
【００３３】
図６に示したように、比較例電池では正極板と集電端子の間の抵抗値が２０ｍΩ〜４０ｍΩの間にありバラツキが大である。これに対して実施例電池では１５ｍΩ〜１６ｍΩと抵抗値の絶対値が小さいし、バラツキも小さい。
【００３４】
図５に示した実施例電池と比較例電池の放電性能の差は、主として極板と集電端子の、接合の良否の差に起因しているものと考えられる。すなわち、比較例電池と比べて、実施例電池が高い放電電圧値を示すのは、実施例電池の方が極板と集電端子間の電気抵抗の絶対値が小さいからである。また、比較例電池の放電容量が低いのは、前記のＮｏ.１、Ｎｏ.８、Ｎｏ.１２のように、一部の極板に集電不良が存在するために、活物質の利用率が低くなったためである。
【００３５】
【発明の効果】
以上詳述した如く、本発明によれば集電端子の価格低減を図ることができる。本発明によれば、集電端子と極板の基板端部を確実に溶接することができるので電池の高率放電性能および電気的性能の信頼性が向上する。本発明によれば、集電端子と外部端子の接合の信頼性を向上することができる。
【００３６】
【図面の簡単な説明】
【図１】本発明に係る電池の極板群の斜視図である。
【図２】本発明に係る電池の極板群を側面から見た図である。
【図３】本発明に係る電池の集電端子を側面から見た図である。
【図４】本発明に係る電池の集電端子を正面から見た図である。
【図５】実施例電池と比較例電池の放電曲線を示すグラフである。
【図６】正極板と正極集電端子の間の電気抵抗を示すグラフである。
【符号の説明】
１正極集電端子
２負極集電端子
３櫛歯
６、７プロジェクション[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery in which a plate-like current collecting terminal is welded to a tabless type electrode plate group, and is intended to provide a battery that is low in price and excellent in volumetric efficiency and electrical property reliability. is there.
[0002]
[Prior art]
In recent years, practical use for environmentally friendly hybrid electric vehicles and electric vehicles has progressed. As important issues for further popularization, the reduction of price and the improvement of energy density for extending the mileage are taken up for the battery as the power source. In addition, since an assembled battery in which a plurality of unit cells are assembled is used for these applications, improvement in reliability of the unit cell performance is required.
[0003]
With regard to battery cost and volume, weight reduction, and electrical performance reliability improvements, improvements to battery structures and components, particularly those related to current collection, are important. Several proposals have already been made for this improvement. Mainly, the first is the adoption of a tabless type current collecting structure in which the substrate end of the electrode plate protrudes from one surface of the electrode plate group, and the substrate end and the plate current collecting terminal are resistance-welded. . Since this structure does not require a plurality of current collecting tabs or leads in the electrode plate group, the distance between the electrode plate group and the terminal is reduced, and the volume occupied by useless space between the two can be reduced. It is also effective in improving the efficiency of the process of welding the current collector to the electrode plate group.
[0004]
The second is improvement of the current collecting terminal. The notch (slit) is provided between the welded portions of the plate-like current collecting terminal, and the slit edge is bent so as to be perpendicular to the plane of the current collecting terminal. The end portion of (described) is in contact with the end portion of the substrate of the electrode plate and welded. By providing the slit, reactive current during welding can be suppressed, and the reliability of welding can be improved. The comb teeth are also effective for improving the reliability of welding between the substrate end and the current collecting terminal.
[0005]
However, the conventional structure in which the plate-like current collecting terminal is partially bent to form comb teeth has the disadvantage that the processing is complicated and the current collecting terminal is expensive.
[0006]
In addition, there is a possibility that the current collecting terminal may be deformed in the comb-teeth forming step, and insufficient contact may occur between the comb teeth and the substrate end of the electrode plate, which may cause poor welding. Further, even when the current collecting terminal is not deformed, it is not possible to reliably eliminate the welding failure between the current collecting terminal and the electrode plate.
[0007]
[Problems to be solved by the invention]
In view of the shortcomings of conventional batteries, the present invention aims to reduce the price of the battery by improving the structure of the current collecting terminal and to improve the reliability in terms of electrical performance.
[0008]
[Means for Solving the Problems]
The present invention includes a step of welding a comb-teeth component provided with comb teeth by bending to a current collector terminal body, and at least one electrode plate protruding from one surface of a group of electrode plates in which a positive electrode plate, a separator, and a negative electrode plate are laminated. And a step of welding the comb teeth of the comb-teeth parts welded to the current collector terminal body at the end of the substrate.
[0009]
Further, the present invention is Rukoto provided projection for resistance welding the joint portion between the external terminals of the plate-shaped current collector terminal preferred.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
3 and 4 are views showing one embodiment of the positive electrode current collector terminal 1 of the battery according to the present invention (the negative electrode current collector terminal can be applied in the same shape and material as the positive electrode current collector terminal. (Omitted). FIG. 3 is a side view of the current collecting terminal, and FIG. 4 is a front view of a surface on which comb teeth are attached by welding. As shown in FIG. 3, the current collecting terminal is composed of two parts, a plate-like current collecting terminal main body 1 and a comb tooth part 3. The comb-tooth component 3 has two opposing sides bent vertically, and a flat portion is welded to the surface of the current collector terminal body 1.
[0011]
In the case of a conventional current collecting terminal, in order to provide comb teeth, a slit is first provided in the current collecting terminal main body, and the edge portion must be bent, and the manufacturing process is complicated. In addition, there is a possibility that the current collector terminal body may be deformed in the process of bending the edge portion of the slit. The current collecting terminal of the battery according to the present invention is a simple process of simply welding the comb-shaped component 3 having comb teeth formed by bending both sides in advance to the plate-shaped current collecting terminal 2 and can be made cheaper.
[0012]
The comb teeth of the current collecting terminal according to the present invention have a thickness of 0.05 to 0.1 mm, a height of 0.3 to 0.7 mm, and a thickness of the current collecting terminal body of 0.3 to 0.8 mm. It is desirable that
[0013]
The thickness of the comb teeth is set to match the mechanical strength and the magnitude of the current flowing therethrough. When the thickness of the comb teeth is reduced, the joint area of the welded portion with the substrate end portion of the electrode plate is reduced, so that the electrical resistance of the portion is increased. When the thickness of the comb teeth is less than 0.05 mm, the high resistance discharge performance of the battery is lowered due to the increase in the electric resistance of the welded portion.
[0014]
Further, if the thickness of the comb teeth is large, it is difficult to weld the comb teeth and the end portion of the substrate by resistance welding. If the thickness of the comb teeth exceeds 0.1 mm, welding cannot be performed reliably, resulting in poor welding with the substrate end portions of some electrode plates. The poor welding leads to a decrease in reliability in terms of electrical performance such that a predetermined discharge performance cannot be obtained. Therefore, it is desirable that the thickness of the comb teeth is set within the above range in consideration of the number of comb teeth and the magnitude of the flowing current.
[0015]
The height of the comb teeth affects the joint area of the welded portion between the comb teeth and the substrate end as well as the thickness of the comb teeth. That is, if the height is low, the bonding area becomes small. If the height of the comb teeth is less than 0.3 mm, the bonding area is small and the electric resistance of the welded portion is increased, which leads to a decrease in the high rate discharge performance of the battery. If the height of the comb teeth is high, comb teeth that do not melt in the welding process remain. For this reason, a gap is generated between the end portion of the substrate and the current collecting terminal body, and a correspondingly useless space is created, which leads to a decrease in the volumetric efficiency of the battery. Accordingly, the height of the comb teeth is desirably in the range of 0.3 to 0.7 mm as described above.
[0016]
The wall thickness of the current collecting terminal body 2 is preferably 0.3 to 0.8 mm, more preferably 0.4 to 0.6 mm.
[0017]
All currents flowing in the battery flow through the current collector terminal body 2. The current collector terminal body 2 plays a role of bundling all the positive plates or negative plates constituting the electrode plate group. If the current collector terminal body is thin, electrical resistance increases and mechanical strength decreases. If the thickness of the current collector terminal body is less than 0.3 mm, the electric resistance is high, which leads to a decrease in the high rate discharge performance of the battery. In addition, due to the lack of mechanical strength of the current collecting terminals, it is difficult to bundle all the electrode plates, and further, the load applied in the resistance welding process cannot be withstood and may be deformed. Therefore, it is desirable that the thickness of the current collecting terminal is 0.3 mm or more, and further 0.4 mm or more.
[0018]
When the thickness of the current collecting terminal body is increased, the reactive current increases when welding the current collecting terminal and the end of the electrode plate substrate, so that welding becomes difficult and the reliability of welding decreases. Moreover, since the weight of a current collection terminal becomes large, the weight efficiency of a battery will fall. The thickness of the current collector terminal body should be 0.8 mm or less, further 0.6 mm or less, taking into account the magnitude of the flowing current, the number of plates, the length of the current path of the current collector terminal, etc. desirable.
[0019]
According to the present invention, since the current collecting terminal can be easily processed, the price can be reduced. Furthermore, according to the present invention name, since the current collector terminal body and the comb teeth are separate parts, the thickness of each can be individually set to an optimum value. This is not possible with the conventional current collecting terminal in which a part of the current collecting terminal body is bent to form comb teeth. In addition, since the comb-teeth part, which is a separate part from the current collector terminal body, is bent in advance, there is no risk of deformation of the current collector terminal body.
[0020]
As shown in FIGS. 3 and 4, a resistance welding projection 6 is provided at a location where the current collector terminal body 1 according to the present invention is joined to an external terminal. Since both the current collector terminal body and the external terminal side joining parts are large in thickness, it is difficult to join them by resistance welding, but the arrangement of the projections ensures the connection between the current collector terminals and the external terminals. This leads to improved reliability of electrical performance.
[0021]
The type of battery to which the present invention is applied is not particularly limited. For example, the present invention can be applied to alkaline storage batteries such as nickel cadmium batteries and nickel metal hydride batteries, and lithium secondary batteries. Further, the shapes of the battery and the electrode plate group are not particularly limited. The present invention can be applied to any of prismatic and cylindrical batteries, a battery having a stacked electrode group, and a battery having a wound electrode group.
[0022]
(Example)
The details of the present invention will be described below by taking, as an example, a rectangular nickel-metal hydride battery provided with a laminated electrode plate group. FIG. 1 is a perspective view of an electrode plate group to which a current collecting terminal according to the battery of this embodiment is attached. FIG. 2 is a view of the electrode plate group viewed from the electrode plate side.
[0023]
12 paste-type nickel positive plates (30 mm wide, 120 mm high, 120 mm wide, hidden capacity invisible in FIG. 2), 30 mm wide, 120 mm high and 0.3 mm thick steel plate 13 electrode hydrogen storage alloy negative electrode plates 4a and 0.15 mm thick polypropylene nonwoven fabric separators 4b were laminated to form an electrode plate group 4.
[0024]
The positive electrode plate is a nickel-made porous substrate having a thickness of 0.5 mm filled with a mixture mainly composed of nickel hydroxide powder, and a strip-shaped unfilled portion having a width of 2 mm is provided on one long side. . A nickel plate having a thickness of 0.3 mm was welded to the unfilled portion.
[0025]
The negative electrode plate was a steel plate substrate having a thickness of 0.06 mm coated with a mixture containing a hydrogen storage alloy as a main component, and a strip-shaped uncoated portion having a width of 2 mm was provided on one long side. The positive electrode plate and the negative electrode plate are laminated with a displacement of 2.5 mm in the width direction, the substrate end portion where the nickel plate is welded to the unfilled portion of the positive electrode plate on one side surface of the electrode plate group, and the negative electrode on the opposite side surface The edge part of the substrate consisting of the uncoated part of the plate was protruded.
[0026]
The positive electrode plate group is fixed, and the positive electrode plate substrate end and the negative electrode plate substrate end protruded from the side surface of the electrode plate group are brought into contact with the comb teeth 3 of the positive electrode collector terminal 1 and the negative electrode collector terminal 2, respectively. Welded by resistance welding. The current collector terminal used was a nickel current collector terminal body 2 having a thickness of 0.4 mm welded with a comb tooth component 3 having a thickness of 0.07 mm, a tooth height of 0.5 mm, and a distance between teeth of 14 mm. It is. In addition, in order to reduce the reactive current at the time of welding and to improve the reliability of welding, a through-hole 5 having a diameter of 6 mmφ was provided between the comb teeth of the current collector terminal body 2 and the comb-tooth component 3.
[0027]
In FIG. 2, in order to clearly indicate the presence of the comb teeth 3, it is unavoidable to draw a gap between the substrate end of the electrode plate and the positive current collecting terminal 1 and the negative current collecting terminal 2. However, since the comb teeth 3 are actually melted by welding, there is almost no gap between the substrate end and the current collector terminal body.
[0028]
The electrode plate group is inserted into the battery case, and projections 6 and 7 provided on the current collecting terminals 1 and 2 (the projection 6 provided on the positive current collecting terminal 1 cannot be seen in the shade) and leads of external terminals are connected. Welded and joined. A predetermined amount of an electrolyte containing an aqueous solution of KOH as a main component was injected, and hermetically sealed by a conventional method to obtain a battery. The manufactured battery has a height of 130 mm, a width of 36 mm, a thickness of 20 mm, and a nominal capacity of 10 Ah.
[0029]
(Comparative example)
A battery was produced under the same conditions as in the example except that a nickel current collector terminal having a thickness of 0.4 mm and not having the comb teeth, projections, and through holes was applied.
[0030]
(Discharge performance evaluation)
The manufactured example battery and comparative example battery were activated and then charged with a current of 5 A for 2.5 hours. Thereafter, it was subjected to a discharge test under the test conditions of a current of 150 A (discharge rate of 15 C) and a final voltage of 0.8 V.
The result is shown in FIG.
[0031]
As shown in FIG. 5, the example battery of the present invention showed higher performance in terms of both discharge voltage and discharge capacity than the comparative example battery.
[0032]
FIG. 6 is a diagram showing the results of measuring the electrical resistance between the twelve positive electrode plates constituting the electrode plate group of the example battery and the comparative example battery and the positive electrode current collecting terminal. In particular, the resistance values of the No. 1, No. 8, and No. 12 electrode plates of the comparative battery are high, suggesting that poor welding has occurred.
[0033]
As shown in FIG. 6, in the comparative battery, the resistance value between the positive electrode plate and the current collecting terminal is between 20 mΩ and 40 mΩ, and the variation is large. On the other hand, in the battery of the embodiment, the absolute value of the resistance value is as small as 15 mΩ to 16 mΩ, and the variation is also small.
[0034]
It is considered that the difference in discharge performance between the example battery and the comparative example battery shown in FIG. 5 is mainly due to the difference in joining quality between the electrode plate and the current collecting terminal. That is, the example battery shows a higher discharge voltage value than the comparative example battery because the absolute value of the electrical resistance between the electrode plate and the current collecting terminal is smaller in the example battery. Further, the discharge capacity of the comparative battery is low because the current collection failure is present in some electrode plates as in No. 1, No. 8, and No. 12, and the utilization rate of the active material This is because of the low.
[0035]
【The invention's effect】
As described in detail above, it is possible to achieve a price reduction of the current collector terminal according to the present onset Akira. According to the present invention , since the current collector terminal and the substrate end of the electrode plate can be reliably welded, the high-rate discharge performance and electrical performance reliability of the battery are improved. According to the onset bright, it is possible to improve the reliability of the bonding of the current collector terminal and the external terminal.
[0036]
[Brief description of the drawings]
FIG. 1 is a perspective view of an electrode plate group of a battery according to the present invention.
FIG. 2 is a side view of an electrode plate group of a battery according to the present invention.
FIG. 3 is a side view of a current collecting terminal of a battery according to the present invention.
FIG. 4 is a front view of a current collecting terminal of a battery according to the present invention.
FIG. 5 is a graph showing discharge curves of an example battery and a comparative battery.
FIG. 6 is a graph showing electrical resistance between a positive electrode plate and a positive electrode current collecting terminal.
[Explanation of symbols]
1 Positive current collecting terminal 2 Negative current collecting terminal 3 Comb teeth 6 and 7 Projection

Claims

A step of welding the bent comb teeth part provided with comb teeth by machining the collector terminal body, the positive electrode plate, the substrate end portion of at least one of the electrode plate protruding from one side of the electrode plate group obtained by stacking a separator and the negative electrode plate And a step of welding the comb teeth of the comb-tooth component welded to the current collecting terminal body.