JP5064699B2 - Cylindrical battery and manufacturing method thereof - Google Patents

Cylindrical battery and manufacturing method thereof Download PDF

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JP5064699B2
JP5064699B2 JP2006049827A JP2006049827A JP5064699B2 JP 5064699 B2 JP5064699 B2 JP 5064699B2 JP 2006049827 A JP2006049827 A JP 2006049827A JP 2006049827 A JP2006049827 A JP 2006049827A JP 5064699 B2 JP5064699 B2 JP 5064699B2
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positive electrode
groove
current collector
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spiral
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JP2007227292A (en
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健二 南坂
智彦 横山
康弘 山内
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Sanyo Electric Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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Description

本発明は、リチウム二次電池やアルカリ蓄電池などの円筒形電池に係り、特に、渦巻状電極群の一方端部に形成された正極芯体露出部に正極集電体が溶接され、渦巻状電極群の他方端部に形成された負極芯体露出部に負極集電体が溶接された電極体を円筒形外装缶内に備えた円筒形電池およびその製造方法に関する。   The present invention relates to a cylindrical battery such as a lithium secondary battery or an alkaline storage battery, and more particularly, a positive electrode current collector is welded to a positive electrode core exposed portion formed at one end of a spiral electrode group, and the spiral electrode The present invention relates to a cylindrical battery having an electrode body in which a negative electrode current collector is welded to a negative electrode core exposed part formed at the other end of the group in a cylindrical outer can and a method for manufacturing the same.

近年、携帯電話、ノートパソコン、小型ビデオカメラ等の携帯用電子・通信機器等に用いられる電源、あるいはハイブリッド車（ＨＥＶ）や電気自動車（ＥＶ）等の電源として、エネルギー密度（Ｗｈ／Ｋｇ）の高いリチウム二次電池などの円筒形電池が注目されている。   In recent years, energy density (Wh / Kg) has been used as a power source for portable electronic / communication devices such as mobile phones, notebook computers, and small video cameras, or as a power source for hybrid vehicles (HEV) and electric vehicles (EV). Cylindrical batteries such as high lithium secondary batteries are attracting attention.

この種の円筒形のリチウム二次電池は、例えば、特許文献１などに示されており、以下のようにして作製されるのが一般的である。即ち、まず、正極芯体（通常は、アルミニウム箔）に正極活物質を含有する正極合剤を塗布して帯状正極板を作製するとともに、負極芯体（通常は、銅箔）に負極活物質を含有する負極合剤を塗布して帯状負極板を作製する。この後、得られた帯状正極板と帯状負極板を帯状セパレータを介して相対向させて積層し、これらを渦巻状に巻回して渦巻状電極群とした後、渦巻状電極群の正極板端部の芯体露出部（正極合剤の未塗布部）と正極集電タブとを溶接するとともに、負極板端部の芯体露出部（負極合剤の未塗布部）と負極集電タブとを溶接して電極体とする。この後、このようにして作製された電極体を円筒形外装缶内に収容し、非水電解液を注液した後、封口体で密閉して円筒形電池としている。   This type of cylindrical lithium secondary battery is disclosed in, for example, Patent Document 1 and is generally manufactured as follows. That is, first, a positive electrode mixture containing a positive electrode active material is applied to a positive electrode core (usually an aluminum foil) to produce a strip-like positive electrode plate, and a negative electrode active material is applied to the negative electrode core (usually a copper foil). A negative electrode mixture containing is applied to produce a strip-shaped negative electrode plate. After that, the obtained belt-like positive electrode plate and the belt-like negative electrode plate are laminated so as to face each other via a belt-like separator, and these are spirally wound to form a spiral electrode group, and then the end of the positive electrode plate of the spiral electrode group Welding the core exposed portion of the part (the uncoated portion of the positive electrode mixture) and the positive electrode current collecting tab, and exposing the core body exposed portion (the uncoated portion of the negative electrode mixture) of the negative electrode plate and the negative electrode current collecting tab Are welded to form an electrode body. Thereafter, the electrode body manufactured in this way is accommodated in a cylindrical outer can, and after pouring a non-aqueous electrolyte, it is sealed with a sealing body to form a cylindrical battery.

ここで、特許文献１に示された電極体について、図４および図５に基づいて説明する。なお、図４は渦巻状電極群に正極集電タブを溶接する状態を模式的に示す図であり、図４（ａ）は、渦巻状電極群の上に正極集電タブを配置してこの正極集電タブにレーザを照射した状態を模式的に示す平面図であり、図４（ｂ）はレーザ照射により渦巻状電極群の上に溶接部が形成された状態を模式的に示す平面図である。また、図５は図４の渦巻状電極群の正極板端部の芯体露出部と正極集電タブとの溶接部の形成状態を模式的に示す図であり、図５（ａ）は正極芯体露出部と正極集電タブとの接触部に溶接部が形成された状態の要部を模式的に示す断面図であり、図５（ｂ）は、渦巻状電極群の正極板の一部を展開して正極芯体露出部に溶接部が形成された状態を模式的に示す図である。 Here, the electrode body disclosed in Patent Document 1 will be described with reference to FIGS. 4 and 5. Incidentally, FIG. 4 is a diagram schematically showing a state of welding the positive electrode current collector tab spiral electrode group, FIG. 4 (a), by placing the positive electrode current collector tabs on the spiral electrode group this is a plan view showing a state of irradiating a laser to the cathode current collector tabs schematically, and FIG. 4 (b) is a plan view of the state in which the welded portion is formed on the spiral electrode group shown schematically by laser irradiation It is. Further, FIG. 5 is a diagram showing a formation state of the welded portion between the core substrate exposed portion and the positive electrode current collecting tab of the positive electrode plate end portion of the spiral electrode group of FIG. 4 schematically, FIG. 5 (a) positive the main part of the state of the welded portion is formed in the contact portion with the substrate exposed portion and the positive electrode current collector tab is a cross-sectional view schematically illustrating, FIG. 5 (b), one positive electrode plate of the spiral electrode group It is a figure which shows typically the state by which the part was expand | deployed and the welding part was formed in the positive electrode core exposed part.

上述した特許文献１に示された渦巻状電極群２０においては、図４に示すように、一方の端部に正極板から延出した正極芯体露出部２１ａが形成されているとともに、他方の端部に負極板から延出した負極芯体露出部（図示せず）が形成されている。そして、正極芯体露出部２１ａの上面に、４つの長方形状の板状体からなる正極集電タブ２２，２３，２４，２５が溶接されているとともに、負極芯体露出部の下面にも正極集電タブとほぼ同様な負極集電タブ（図示せず）が溶接されている。なお、負極集電タブの溶接は正極集電タブの溶接と同様であるので、以下では、正極集電タブの溶接についてのみ説明する。 In the spiral electrode group 20 shown in Patent Document 1 described above, as shown in FIG. 4, a positive electrode core exposed portion 21 a extending from the positive electrode plate is formed at one end portion, and the other end is formed. A negative electrode core exposed portion (not shown) extending from the negative electrode plate is formed at the end. The positive electrode current collecting tabs 22, 23, 24, and 25 made of four rectangular plates are welded to the upper surface of the positive electrode core exposed portion 21 a, and the lower surface of the negative electrode core exposed portion also has a positive electrode. A negative electrode current collecting tab (not shown) substantially similar to the current collecting tab is welded. Since welding of the negative electrode current collecting tab is similar to welding of the positive electrode current collecting tab, only the welding of the positive electrode current collecting tab will be described below.

ここで、正極芯体露出部２１ａの上面に４つの正極集電タブ２２，２３，２４，２５を溶接する際には、正極芯体露出部２１ａの上面に４つの正極集電タブ２２，２３，２４，２５を配置し、これらの正極集電タブ２２，２３，２４，２５の上に２列のレーザ光を照射して正極芯体露出部２１ａに各正極集電タブ２２，２３，２４，２５を溶接するようにしている。この場合、図４（ａ）に示すように、正極集電タブ２２の上にレーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１と、レーザスポットＦ１，Ｇ１，Ｈ１，Ｉ１，Ｊ１とが渦巻の巻回方向に対して同位置になるようにレーザ光が照射されるようになされている。   Here, when the four positive current collecting tabs 22, 23, 24, 25 are welded to the upper surface of the positive electrode core exposed portion 21a, the four positive current collecting tabs 22, 23 are disposed on the upper surface of the positive electrode core exposed portion 21a. , 24, 25 are arranged, and two rows of laser beams are irradiated on these positive electrode current collecting tabs 22, 23, 24, 25 to expose each positive electrode current collecting tab 22, 23, 24 to the positive electrode core exposed portion 21a. , 25 are welded. In this case, as shown in FIG. 4A, the laser spots A1, B1, C1, D1, E1 and the laser spots F1, G1, H1, I1, J1 are spirally wound on the positive electrode current collecting tab 22. Laser light is irradiated so as to be in the same position with respect to the rotation direction.

同様に、正極集電タブ２３の上にレーザスポットＡ２，Ｂ２，Ｃ２，Ｄ２，Ｅ２と、レーザスポットＦ２，Ｇ２，Ｈ２，Ｉ２，Ｊ２とが渦巻の巻回方向に対して同位置になるようにレーザ光が照射される。また、正極集電タブ２４の上にレーザスポットＡ３，Ｂ３，Ｃ３，Ｄ３，Ｅ３と、レーザスポットＦ３，Ｇ３，Ｈ３，Ｉ３，Ｊ３とが渦巻の巻回方向に対して同位置になるようにレーザ光が照射され、さらに、正極集電タブ２４の上にレーザスポットＡ４，Ｂ４，Ｃ４，Ｄ４，Ｅ４と、レーザスポットＦ４，Ｇ４，Ｈ４，Ｉ４，Ｊ４とが渦巻の巻回方向に対して同位置になるようにレーザ光が照射される。
（２３，２４，２５） Similarly, the laser spots A2, B2, C2, D2, and E2 and the laser spots F2, G2, H2, I2, and J2 are on the positive electrode current collecting tab 23 at the same position with respect to the spiral winding direction. Is irradiated with laser light. Further, the laser spots A3, B3, C3, D3, and E3 and the laser spots F3, G3, H3, I3, and J3 are located at the same position on the positive electrode current collecting tab 24 with respect to the spiral winding direction. Laser light is irradiated, and laser spots A4, B4, C4, D4, and E4 and laser spots F4, G4, H4, I4, and J4 are formed on the positive electrode current collecting tab 24 with respect to the spiral winding direction. Laser light is irradiated so as to be in the same position.
(23, 24, 25)

ところで、上面にレーザスポット（Ａ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１など）が形成された正極集電タブ２２（２３，２４，２５）の下面においては、レーザスポットにより発熱することとなるが、図５（ａ）に示すように、この発熱部の径はレーザスポット径よりも小径となる（なお、小径となる程度は正極集電タブの厚みや材質により異なる）のが一般的である。このため、図４（ｂ）に示すように、例えば、正極芯体露出部２１ａの端部と各正極集電タブ２２の下面接触部とに形成される溶接部ａ１，ｂ１，ｃ１，ｄ１，ｅ１およびｆ１，ｇ１，ｈ１，ｉ１，ｊ１の径は、レーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１およびＦ１，Ｇ１，Ｈ１，Ｉ１，Ｊ１のスポット径よりも小径となる。なお、他のレーザスポット溶接部ａ２，ｂ２，ｃ２，ｄ２，ｅ２（ｆ２，ｇ２，ｈ２，ｉ２，ｊ２）、ａ３，ｂ３，ｃ３，ｄ３，ｅ３（ｆ３，ｇ３，ｈ３，ｉ３，ｊ３）、ａ４，ｂ４，ｃ４，ｄ４，ｅ４（ｆ４，ｇ４，ｈ４，ｉ４，ｊ４）においても同様である。
特開２０００−４０５０２号公報 By the way, on the lower surface of the positive electrode current collecting tab 22 (23, 24, 25) in which the laser spot (A1, B1, C1, D1, E1, etc.) is formed on the upper surface, heat is generated by the laser spot. As shown in FIG. 5 (a), the diameter of the heat generating portion is generally smaller than the laser spot diameter (note that the degree of the small diameter varies depending on the thickness and material of the positive electrode current collecting tab). Therefore, as shown in FIG. 4B, for example, welds a1, b1, c1, d1, formed at the end of the positive electrode core exposed portion 21a and the lower surface contact portion of each positive electrode current collecting tab 22 are formed. The diameters of e1, f1, g1, h1, i1, and j1 are smaller than the spot diameters of laser spots A1, B1, C1, D1, and E1, and F1, G1, H1, I1, and J1. Other laser spot welds a2, b2, c2, d2, e2 (f2, g2, h2, i2, j2), a3, b3, c3, d3, e3 (f3, g3, h3, i3, j3), The same applies to a4, b4, c4, d4 and e4 (f4, g4, h4, i4 and j4).
JP 2000-40502 A

ところが、上述のようにレーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１（Ｆ１，Ｇ１，Ｈ１，Ｉ１，Ｊ１）のスポット径よりも小径な溶接部ａ１，ｂ１，ｃ１，ｄ１，ｅ１（ｆ１，ｇ１，ｈ１，ｉ１，ｊ１）が形成されると、図５に示すように、正極芯体露出部２１ａの端部のレーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１（Ｆ１，Ｇ１，Ｈ１，Ｉ１，Ｊ１）の列方向（渦巻状電極群２０の径方向）に未溶接部ｘが形成されるようになる。そして、このような未溶接部ｘが渦巻状電極群２０の径方向に形成されると、正極芯体露出部２１ａの端部から均一に集電することができなくなるため、内部抵抗が上昇し、特に、大電流用途の電源に用いられる電池においては、内部抵抗に起因して電圧降下が大きくなるという問題を生じた。   However, as described above, the welded portions a1, b1, c1, d1, e1 (f1, g1) smaller in diameter than the spot diameters of the laser spots A1, B1, C1, D1, E1 (F1, G1, H1, I1, J1). , H1, i1, j1) are formed, as shown in FIG. 5, laser spots A1, B1, C1, D1, E1 (F1, G1, H1, I1, F1) at the ends of the positive electrode core exposed portion 21a. The unwelded portion x is formed in the column direction J1) (the radial direction of the spiral electrode group 20). When such an unwelded portion x is formed in the radial direction of the spiral electrode group 20, current cannot be collected uniformly from the end of the positive electrode core exposed portion 21a, and the internal resistance increases. In particular, a battery used for a power source for large current applications has a problem that a voltage drop is increased due to internal resistance.

この場合、未溶接部ｘが形成されないようにレーザを照射するようにすればよいと考えられるが、スポット径よりも小径な溶接部になることを見越して、レーザスポットが重なり合うようにレーザを照射する必要がある。ところが、レーザスポットが重なり合うようにレーザを照射するようにすると、レーザの照射熱により電極群中に存在するセパレータに熱的影響を及ぼしたり、あるいは集電タブ（集電体）からスパッタが発生して、これが電極群中に入り込むことにより短絡が生じるという新たな問題が発生するようになる。   In this case, it may be sufficient to irradiate the laser so that the unwelded portion x is not formed. However, in anticipation of a welded portion having a diameter smaller than the spot diameter, the laser is irradiated so that the laser spots overlap. There is a need to. However, if the laser is irradiated so that the laser spots overlap, the separator in the electrode group is thermally affected by the irradiation heat of the laser, or spatter is generated from the current collector tab (current collector). As a result, a new problem arises in that a short circuit occurs when the electrode enters the electrode group.

また、上述した特許文献１に示されるように、４つの正極集電タブを正極芯体露出部の上に配置し、これらの正極集電タブにレーザを照射して溶接する方法にあっては、部品点数が多いことから、その溶接方法が複雑でハンドリングも面倒であるとともに、作業性も悪いことから生産効率が低下するという問題も生じた。
そこで、本発明は上記問題点を解消するためになされたものであって、極板から均一に集電できて内部抵抗の低減化が可能な集電構造となる円筒形電池を提供するとともに、製造が容易で生産効率も向上し、かつセパレータに熱的影響を及ぼしたりあるいは短絡が生じることがない円筒形電池の製造方法を提供することを目的とする。 In addition, as shown in Patent Document 1 described above, in the method of arranging four positive electrode current collecting tabs on the positive electrode core exposed portion and irradiating these positive electrode current collecting tabs with a laser for welding. Since the number of parts is large, the welding method is complicated, handling is troublesome, and workability is also poor, so that production efficiency is lowered.
Therefore, the present invention was made to solve the above problems, and provided a cylindrical battery having a current collecting structure capable of collecting current uniformly from an electrode plate and reducing internal resistance, An object of the present invention is to provide a method of manufacturing a cylindrical battery that is easy to manufacture, improves production efficiency, and does not affect the separator thermally or cause a short circuit.

本発明の円筒形電池は、渦巻状電極群の巻軸方向の一方端部に位置する渦巻状の正極芯体露出部の端面に正極集電体が溶接され、前記渦巻状電極群の巻軸方向の他方端部に位置する渦巻状の負極芯体露出部の端面に負極集電体が溶接された電極体を円筒形外装缶内に備えている。そして、上記目的を達成するため、正極集電体および負極集電体の少なくとも一方は中心開口と当該中心開口から放射状に形成された溝部とを備えており、溝部の幅方向に少なくとも２列以上の当該溝部の長さ方向に沿ったエネルギー線の照射により当該溝部と芯体露出部との接触部でエネルギー線の照射位置に溶接部が形成されており、溶接部は溝部の幅方向に少なくとも２列以上で当該溝部の長さ方向に沿って不連続な溶接部列となるように形成されているとともに、溶接部列の１列目に形成された不連続な各溶接部の間で当該第１列目とは溝部の幅方向に異なる位置に２列目以降に形成された不連続な各溶接部が形成されていることを特徴とする。 In the cylindrical battery of the present invention, a positive electrode current collector is welded to the end face of the spiral positive electrode core exposed portion located at one end portion in the winding axis direction of the spiral electrode group, and the winding shaft of the spiral electrode group A cylindrical outer can is provided with an electrode body in which a negative electrode current collector is welded to an end face of a spiral negative electrode core exposed portion located at the other end in the direction . In order to achieve the above object, at least one of the positive electrode current collector and the negative electrode current collector includes a center opening and a groove formed radially from the center opening, and at least two or more rows in the width direction of the groove The weld portion is formed at the energy beam irradiation position at the contact portion between the groove portion and the core exposed portion by irradiation of the energy ray along the length direction of the groove portion, and the weld portion is at least in the width direction of the groove portion. It is formed so as to be a discontinuous weld row along the length direction of the groove portion in two or more rows, and between the discontinuous weld portions formed in the first row of the weld portion row Discontinuous welds formed after the second row are formed at positions different from the first row in the width direction of the groove.

このように溶接部は溝部の幅方向に少なくとも２列以上で当該溝部の長さ方向に沿って不連続な溶接部列となるように形成されているとともに、溶接部列の１列目に形成された不連続な各溶接部の間で当該第１列目とは溝部の幅方向に異なる位置に２列目以降に形成された不連続な各溶接部が形成されていると、極板から集電体に均一に集電できるようになる。これにより、内部抵抗の低減化が可能な集電構造が得られるようになる。この場合、製造の容易さを考慮すると、溝部は中心開口から互に直角となる４方向に形成されているのが望ましい。   As described above, the welded portion is formed so as to be a discontinuous weld portion row along the length direction of the groove portion in at least two rows in the width direction of the groove portion, and is formed in the first row of the weld portion row. If the discontinuous welds formed in the second and subsequent rows are formed at different positions in the width direction of the groove portion from the discontinuous welds, the electrode plate It becomes possible to collect current uniformly on the current collector. As a result, a current collecting structure capable of reducing the internal resistance can be obtained. In this case, considering the ease of manufacture, it is desirable that the groove portions are formed in four directions perpendicular to each other from the central opening.

なお、上述のような集電構造となる円筒形電池を製造するには、中心開口と当該中心開口から放射状に形成された溝部とを備えた正極集電体もしくは負極集電体を用い、溝部の長さ方向に沿った列に並ぶ不連続な溶接部が形成されるように溝部の長さ方向に沿って第１列目のエネルギー線を照射する第１列目エネルギー線照射工程と、第２列目以降のエネルギー線の照射により形成された溝部の長さ方向に沿った列に並ぶ不連続な溶接部が第１列目のエネルギー線の照射により形成された溝部の長さ方向に沿った列に並ぶ不連続な溶接部の間に形成されるように第１列目とは溝部の幅方向に異なる位置に第２列目以降のエネルギー線を照射する第２列目以降エネルギー線照射工程とを備えるようにすればよい。なお、エネルギー線としては、電子線やレーザ光を用いることができるが、製造の容易さの観点からすると、レーザ光を用いるのが望ましい。
Note that to manufacture a cylindrical battery comprising a collector structure as described above, the positive electrode collector if Ku and a groove portion formed radially from the central opening and the central opening with a negative electrode current collector A first-row energy beam irradiating step of irradiating the first-row energy beam along the length direction of the groove portion so as to form discontinuous welds arranged in a row along the length direction of the groove portion; , the length direction of the formed grooves by irradiation with a discontinuous weld line up in rows along the length of the formed grooves by the irradiation of the second row and subsequent energy rays first column of the energy ray Energy from the second column on which energy rays from the second column are irradiated to a position different from the first column in the width direction of the groove so as to be formed between discontinuous welds arranged in a row along A line irradiation process may be provided. In addition, although an electron beam and a laser beam can be used as an energy beam, it is desirable to use a laser beam from a viewpoint of ease of manufacture.

上述したように、本発明の円筒形電池においては、極板から均一に集電できる集電構造となるようになされているので、内部抵抗の低減した円筒形電池を得ることが可能となるとともに、セパレータに熱的影響を及ぼしたりあるいは短絡が生じることがない円筒形電池を製造方法することが可能となる。   As described above, the cylindrical battery according to the present invention has a current collecting structure capable of collecting current uniformly from the electrode plate, so that a cylindrical battery with reduced internal resistance can be obtained. It is possible to manufacture a cylindrical battery that does not affect the separator thermally or cause a short circuit.

ついで、本発明の実施の形態を図１〜図３に基づいて以下に説明するが、本発明はこの実施の形態に何ら限定されるものではなく、本発明の目的を変更しない範囲で適宜変更して実施することが可能である。なお、図１は本発明の渦巻状電極群と正極集電体を模式的に示す斜視図である。図２は本発明の渦巻状電極群に正極集電体を溶接する状態を模式的に示す図であり、図２（ａ）は、図１の渦巻状電極群の上に正極集電体を配置してこの正極集電体にレーザを照射した状態を模式的に示す平面図であり、図２（ｂ）はレーザ照射により渦巻状電極群の上に溶接部形成された状態を模式的に示す平面図である。図３は、図１の渦巻状電極群の正極板と正極集電体との溶接部の形成状態を模式的に示す図であり、図３（ａ）は正極芯体露出部と正極集電体との接触部に溶接部が形成された状態の要部を模式的に示す断面図であり、図３（ｂ）は、渦巻状電極群の正極板の一部を展開して溶接部が形成された状態を模式的に示す図である。 Next, an embodiment of the present invention will be described below with reference to FIGS. 1 to 3, but the present invention is not limited to this embodiment at all, and can be appropriately changed without changing the object of the present invention. Can be implemented. Incidentally, FIG. 1 is a perspective view schematically showing a wound electrode group and the positive electrode current collector of the present invention. Figure 2 is a diagram schematically showing a state of welding the positive electrode current collector to the spiral electrode group of the present invention, FIG. 2 (a), the positive electrode current collector on the spiral electrode group of FIG. 1 disposed to a plan view showing a state of irradiating a laser beam to the cathode current collector schematically FIG. 2 (b) the state of being welded portion formed on the spiral electrode group schematically by laser irradiation FIG. Figure 3 is a diagram showing a formation state of the welded portion between the positive electrode plate and the positive electrode current collector of the spiral electrode group of FIG. 1 schematically, Fig. 3 (a) positive electrode substrate exposed portion and the positive electrode current collector the main part of the state of the welding portion is formed on the contact portion of the body is a cross-sectional view schematically illustrating, FIG. 3 (b), welds expand a portion of the positive electrode plate of the spiral electrode group It is a figure which shows the formed state typically.

１．正極板
正極活物質としてのコバルト酸リチウム（ＬｉＣｏＯ2）粉末９４質量％と、導電剤としてのアセチレンブラックあるいはグラファイトなどの炭素系粉末３質量％とを混合して正極合剤を調製した。この正極合剤と、ポリフッ化ビニリデン（ＰＶｄＦ）からなる結着剤３質量％とをＮ−メチル−２−ピロリドン（ＮＭＰ）からなる有機溶剤に溶解した結着剤溶液とを混練して、正極活物質スラリーを調製した。なお、正極活物質としては上述したＬｉＣｏＯ2以外に、ＬｉxＭＯ2（但し、ＭはＣｏ，Ｎｉ，Ｍｎの少なくとも１種で、０．４５≦ｘ≦１．２０）で表されるリチウム遷移金属複合酸化物、例えば、ＬｉＮｉＯ2，ＬｉＮｉyＣｏ1-yＯ2（但し、０．０１≦ｙ≦０．９９），Ｌｉ0.5ＭｎＯ2，ＬｉＭｎＯ2などの１種単独、もしくは複数種を混合して用いるようにしてもよい。 1. Positive electrode plate A positive electrode mixture was prepared by mixing 94% by mass of lithium cobaltate (LiCoO 2 ) powder as a positive electrode active material and 3% by mass of carbon-based powder such as acetylene black or graphite as a conductive agent. This positive electrode mixture was kneaded with a binder solution prepared by dissolving 3% by mass of a binder composed of polyvinylidene fluoride (PVdF) in an organic solvent composed of N-methyl-2-pyrrolidone (NMP). An active material slurry was prepared. In addition to the above-described LiCoO 2 , the positive electrode active material is Li x MO 2 (where M is at least one of Co, Ni, and Mn, and 0.45 ≦ x ≦ 1.20). Metal composite oxide, for example, LiNiO 2 , LiNi y Co 1-y O 2 (where 0.01 ≦ y ≦ 0.99), Li 0.5 MnO 2 , LiMnO 2, etc. You may make it use.

ついで、アルミニウム箔（例えば、厚みが２０μｍのもの）からなる正極芯体１１ａを用意し、上述のように作製した正極活物質スラリーを正極芯体１１ａの片面に均一に塗布して、正極合剤層１１ｂを形成した。この場合、正極合剤層１１ｂの上側には正極活物質スラリーの塗布されていない所定幅（ここで、１０ｍｍとした）の非塗布部（正極芯体露出部）１１ｃが正極芯体１１ａの端縁に沿って形成されるように塗布した。この後、乾燥機中を通過させて、スラリー作製時に必要であった有機溶剤（ＮＭＰ）を除去して乾燥させた。乾燥後、ロールプレス機により厚みが０．０６ｍｍになるまで圧延して正極板を作製した。このようにして作製した正極板を幅が９６ｍｍとなる短冊状に切り出し、幅が１０ｍｍの帯状の正極芯体露出部１１ｃを設けた正極板１１を得た。   Next, a positive electrode core 11a made of an aluminum foil (for example, having a thickness of 20 μm) is prepared, and the positive electrode active material slurry prepared as described above is uniformly applied to one surface of the positive electrode core 11a. Layer 11b was formed. In this case, on the upper side of the positive electrode mixture layer 11b, a non-applied portion (positive electrode core exposed portion) 11c having a predetermined width (here, 10 mm) where the positive electrode active material slurry is not applied is an end of the positive electrode core body 11a. It was applied so as to form along the edge. Then, it was made to pass through a drier to remove the organic solvent (NMP) that was necessary at the time of slurry preparation and to dry. After drying, it was rolled with a roll press machine to a thickness of 0.06 mm to produce a positive electrode plate. The positive electrode plate thus produced was cut into a strip shape having a width of 96 mm to obtain a positive electrode plate 11 provided with a strip-shaped positive electrode core exposed portion 11c having a width of 10 mm.

２．負極板
負極活物質としての天然黒鉛粉末９８質量％と、結着剤としてのカルボキシメチルセルロース（ＣＭＣ）およびスチレンブタジエンゴム（ＳＢＲ）をそれぞれ１質量％ずつ混合し、水を加えて混練して負極活物質スラリーを調製した。なお、負極活物質としては上述した天然黒鉛以外に、リチウムイオンを吸蔵・脱離し得るカーボン系材料、例えば、人造黒鉛、カーボンブラック、コークス、ガラス状炭素、炭素繊維、またはこれらの焼成体等を用いてもよいし、金属リチウム、リチウム−アルミニウム合金、リチウム−鉛合金、リチウム−錫合金等のリチウム合金、ＳｎＯ2、ＳｎＯ、ＴｉＯ2、Ｎｂ2Ｏ3等の電位が正極活物質に比べて卑な金属酸化物を用いてもよい。 2. Negative electrode plate 98% by mass of natural graphite powder as the negative electrode active material and 1% by mass of carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR) as the binder were mixed, kneaded and mixed with water. A material slurry was prepared. As the negative electrode active material, in addition to the above-mentioned natural graphite, a carbon-based material capable of occluding and desorbing lithium ions, such as artificial graphite, carbon black, coke, glassy carbon, carbon fiber, or a fired body thereof. May be used, and the potential of lithium alloys such as metallic lithium, lithium-aluminum alloy, lithium-lead alloy, lithium-tin alloy, SnO 2 , SnO, TiO 2 , Nb 2 O 3, etc. is higher than the positive electrode active material. A base metal oxide may be used.

ついで、銅箔（例えば、厚みが１２μｍのもの）からなる負極芯体１２ａを用意し、上述のように作製した負極活物質スラリーを負極芯体１２ａの片面に均一に塗布して、負極合剤層１２ｂを形成した。この場合、負極合剤層１２ｂの下側には負極活物質スラリーの塗布されていない所定幅（ここで、８ｍｍとした）の非塗布部（負極芯体露出部）１２ｃが形成されるように塗布した。この後、乾燥機中を通過させて乾燥させた。乾燥後、ロールプレス機により厚みが０．０５ｍｍになるまで圧延して負極板を作製した。このようにして作製した負極板を幅が９８ｍｍとなる短冊状に切り出し、幅が８ｍｍの帯状の負極芯体露出部１２ｃを設けた負極板１２を得た。   Next, a negative electrode core body 12a made of copper foil (for example, having a thickness of 12 μm) is prepared, and the negative electrode active material slurry prepared as described above is uniformly applied to one surface of the negative electrode core body 12a. Layer 12b was formed. In this case, a non-applied portion (negative electrode core exposed portion) 12c having a predetermined width (here, 8 mm) where the negative electrode active material slurry is not applied is formed below the negative electrode mixture layer 12b. Applied. Then, it was dried by passing through a dryer. After drying, it was rolled with a roll press machine to a thickness of 0.05 mm to produce a negative electrode plate. The negative electrode plate thus produced was cut into a strip shape having a width of 98 mm to obtain a negative electrode plate 12 provided with a strip-shaped negative electrode core exposed portion 12c having a width of 8 mm.

３．渦巻状電極群
ついで、ポリエチレン製微多孔膜（厚みが０．０２２ｍｍで、幅が１００ｍｍのもの）からなる帯状セパレータ１３，１３を用意し、上述のようにして作製した正極板１１と負極板１２とをそれぞれセパレータ１３，１３上に配置して幅方向へずらすとともに、これらの幅方向の中心線が一致するように重ね合わせた。これにより、正極芯体露出部１１ｃおよび負極芯体露出部１２ｃはセパレータ１３の両端縁からそれぞれ外側へ突出することとなる。この後、巻取機によりこれらを渦巻状に巻回した後、最外周をテープ止めして渦巻状電極群１０を作製した。なお、このようにして作製された渦巻状電極群１０においては、一方の端部では正極板１１の正極芯体露出部１１ｃがセパレータ１３の一方の端縁よりも外方へ突出し、他方の端部では負極板１２の負極芯体露出部１２ｃがセパレータ１３の他方の端縁よりも外方へ突出している。 3. A spiral electrode group Next, strip separators 13 and 13 made of a polyethylene microporous film (thickness of 0.022 mm and width of 100 mm) are prepared, and the positive electrode plate 11 and the negative electrode plate 12 manufactured as described above. Were placed on the separators 13 and 13 and shifted in the width direction, and overlapped so that the center lines in the width direction coincided with each other. As a result, the positive electrode core exposed portion 11c and the negative electrode core exposed portion 12c protrude from the both end edges of the separator 13 outward. Then, after winding these in a spiral shape with a winder, the outermost periphery was taped to produce a spiral electrode group 10. In the spiral electrode group 10 manufactured in this way, the positive electrode core exposed portion 11c of the positive electrode plate 11 projects outward from one edge of the separator 13 at one end, and the other end. The negative electrode core exposed portion 12 c of the negative electrode plate 12 protrudes outward from the other edge of the separator 13.

ついで、集電体を用意する。なお、図１においては、正極集電体１４のみを図示しているが、負極集電体も正極集電体１４とほぼ同様な構成となるので、その説明は省略する。この場合、正極集電体１４は、図１に示すように、円形の平板状本体部１４ａと、この本体部１４ａから延出したリード部１４ｅとを備え、これらが一体的に形成されている。また、平板状本体部１４ａには、その中心部に中心開口１４ｂと、この中心開口１４ｂから放射状に伸びる複数本の断面形状が略Ｕ状の溝１４ｃと、中心開口１４ｂの周囲に複数の注液孔１４ｄとを備え、これらが一体的に形成されている。   Next, prepare a current collector. In FIG. 1, only the positive electrode current collector 14 is illustrated, but the negative electrode current collector has substantially the same configuration as the positive electrode current collector 14, and thus description thereof is omitted. In this case, as shown in FIG. 1, the positive electrode current collector 14 includes a circular flat plate-like main body portion 14a and a lead portion 14e extending from the main body portion 14a, and these are integrally formed. . Further, the flat plate-like main body portion 14a has a central opening 14b at the center thereof, a plurality of cross-sectionally extending grooves 14c extending radially from the central opening 14b, and a plurality of notes around the central opening 14b. The liquid hole 14d is provided, and these are integrally formed.

ついで、渦巻状電極群１０の端部に形成されている正極芯体露出部１１ｃに正極集電体１４の本体部１４ａを押し付けることにより、正極集電体１４の溝１４ｃを正極芯体露出部１１ｃに食い込ませて、断面形状が略Ｕ状の溝１４ｃの先端部と正極芯体露出部１１ｃとの間に円筒面からなる接合面を形成させる。この状態で、正極集電体１４の溝１４ｃの内周面に向けてレーザビームを照射してレーザスポット溶接を施す。この場合、図２（ａ）に示すように、まず、正極集電体１４の第１番目の溝１４ｃ−１の幅方向の図示下側に正極集電体１４の中心開口１４ｂから端縁に向けてレーザビーム１−１を照射して、第１番目の溝１４ｃ−１の表面長手方向に１列目のレーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１を形成させる。   Next, the main body portion 14a of the positive electrode current collector 14 is pressed against the positive electrode core body exposed portion 11c formed at the end of the spiral electrode group 10, so that the groove 14c of the positive electrode current collector 14 is formed into the positive electrode core body exposed portion. 11 c is formed to form a cylindrical joint surface between the tip end portion of the groove 14 c having a substantially U-shaped cross section and the positive electrode core exposed portion 11 c. In this state, laser spot welding is performed by irradiating the inner circumferential surface of the groove 14c of the positive electrode current collector 14 with a laser beam. In this case, as shown in FIG. 2A, first, from the central opening 14b of the positive electrode current collector 14 to the edge on the lower side in the width direction of the first groove 14c-1 of the positive electrode current collector 14 The first laser spot A1, B1, C1, D1, E1 is formed in the longitudinal direction of the surface of the first groove 14c-1.

この後、正極集電体１４の第２番目の溝１４ｃ−２の幅方向の図示左側に正極集電体１４の中心開口１４ｂから端縁に向けてレーザビーム１−２を照射して、第２番目の溝１４ｃ−２の表面長手方向に１列目のレーザスポットＡ２，Ｂ２，Ｃ２，Ｄ２，Ｅ２を形成させる。同様に、第３番目の溝１４ｃ−３の幅方向の図示上側にレーザビーム１−３を照射して、第３番目の溝１４ｃ−３の表面長手方向に１列目のレーザスポットＡ３，Ｂ３，Ｃ３，Ｄ３，Ｅ３を形成させ、第４番目の溝１４ｃ−４の幅方向の図示右側にレーザビーム１−４を照射して、第４番目の溝１４ｃ−４の表面長手方向に１列目のレーザスポットＡ４，Ｂ４，Ｃ４，Ｄ４，Ｅ４を形成させる。なお、図２（ａ）においては、レーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１（Ａ２，Ｂ２，Ｃ２，Ｄ２，Ｅ２、Ａ３，Ｂ３，Ｃ３，Ｄ３，Ｅ３、Ａ４，Ｂ４，Ｃ４，Ｄ４，Ｅ４）を形成させるようにしているが、あくまでもレーザスポットの個数は模式的に示すものであって、実際には、渦巻状電極群１０の巻数や正極集電体１４の材質や板厚に応じて適宜個数となるように設定することとなる。   Thereafter, the laser beam 1-2 is irradiated from the center opening 14b of the positive electrode current collector 14 toward the edge on the left side in the width direction of the second groove 14c-2 of the positive electrode current collector 14, Laser spots A2, B2, C2, D2, E2 in the first row are formed in the longitudinal direction of the surface of the second groove 14c-2. Similarly, the laser beam 1-3 is irradiated on the upper side of the third groove 14c-3 in the width direction in the figure, and the laser spots A3, B3 in the first row in the longitudinal direction of the surface of the third groove 14c-3. , C3, D3, and E3 are formed, the laser beam 1-4 is irradiated to the right side of the fourth groove 14c-4 in the width direction in the figure, and one row extends in the longitudinal direction of the surface of the fourth groove 14c-4. Laser spots A4, B4, C4, D4 and E4 of the eyes are formed. In FIG. 2 (a), laser spots A1, B1, C1, D1, E1 (A2, B2, C2, D2, E2, A3, B3, C3, D3, E3, A4, B4, C4, D4). E4) is formed, but the number of laser spots is schematically shown. Actually, the number depends on the number of turns of the spiral electrode group 10, the material of the positive electrode current collector 14, and the plate thickness. Thus, the number is set as appropriate.

ここで、レーザスポットＡ１・・・（Ａ２・・・、Ａ３・・・、Ａ４・・・）が溝１４ｃの表面長手方向に形成されることにより、図２（ｂ）に示すように、溝１４ｃの先端部と正極芯体露出部１１ｃとの接合面に溝１４ｃの長手方向に沿って１列目の溶接部ａ１，ｂ１，ｃ１，ｄ１，ｅ１（ａ２，ｂ２，ｃ２，ｄ２，ｅ２、ａ３，ｂ３，ｃ３，ｄ３，ｅ３、ａ４，ｂ４，ｃ４，ｄ４，ｅ４）がそれぞれ形成されることとなる。なお、溶接部ａ１・・・（ａ２・・・、ａ３・・・、ａ４・・・）の径がレーザスポットＡ１・・・（Ａ２・・・、Ａ３・・・、Ａ４・・・）の径よりも小径となるのは、レーザスポットＡ１・・・（Ａ２・・・、Ａ３・・・、Ａ４・・・）に生じた熱が溶接部ａ１・・・（ａ２・・・、ａ３・・・、ａ４・・・）に伝達するまでに熱ロスが発生するためである。   Here, the laser spots A1... (A2... A3... A4...) Are formed in the longitudinal direction of the surface of the groove 14c, so that the grooves as shown in FIG. 14c on the joint surface between the tip of 14c and the positive electrode core exposed portion 11c along the longitudinal direction of the groove 14c, the first row of welded portions a1, b1, c1, d1, e1 (a2, b2, c2, d2, e2, a3, b3, c3, d3, e3, a4, b4, c4, d4, e4) are formed, respectively. In addition, the diameter of the welding part a1 ... (a2 ..., a3 ..., a4 ...) is the laser spot A1 ... (A2 ..., A3 ..., A4 ...). The diameter becomes smaller than the diameter because the heat generated in the laser spots A1... (A2... A3... A4. This is because a heat loss occurs until it is transmitted to a4 ...).

この後、図２（ａ）に示すように、正極集電体１４の第１番目の溝１４ｃ−１の幅方向の図示上側に正極集電体１４の中心開口１４ｂから端縁に向けてレーザビーム２−１を照射して、第１番目の溝１４ｃ−１の表面長手方向に２列目のレーザスポットＦ１，Ｇ１，Ｈ１，Ｉ１，Ｊ１を形成させる。同様に、第２番目の溝１４ｃ−２の幅方向の図示右側にレーザビーム２−２を照射して第２番目の溝１４ｃ−２の表面長手方向に２列目のレーザスポットＦ２，Ｇ２，Ｈ２，Ｉ２，Ｊ２を形成させ、第３番目の溝１４ｃ−３の幅方向の図示下側にレーザビーム２−３を照射して第３番目の溝１４ｃ−３の表面長手方向に２列目のレーザスポットＦ３，Ｇ３，Ｈ３，Ｉ３，Ｊ３を形成させ、第４番目の溝１４ｃ−４の幅方向の図示左側にレーザビーム２−４を照射して第４番目の溝１４ｃ−４の表面長手方向に２列目のレーザスポットＦ４，Ｇ４，Ｈ４，Ｉ４，Ｊ４を形成させる。   Thereafter, as shown in FIG. 2A, the laser is directed from the center opening 14b of the positive electrode current collector 14 toward the edge on the upper side in the width direction of the first groove 14c-1 of the positive electrode current collector 14. The beam 2-1 is irradiated to form the second row of laser spots F1, G1, H1, I1, and J1 in the longitudinal direction of the surface of the first groove 14c-1. Similarly, a laser beam 2-2 is irradiated on the right side of the second groove 14c-2 in the width direction in the figure, and the second row of laser spots F2, G2, in the longitudinal direction of the surface of the second groove 14c-2. H2, I2, and J2 are formed, and a laser beam 2-3 is irradiated on the lower side in the width direction of the third groove 14c-3 to form a second row in the longitudinal direction of the surface of the third groove 14c-3. Laser spots F3, G3, H3, I3, and J3 are formed, and a laser beam 2-4 is irradiated on the left side of the fourth groove 14c-4 in the width direction in the figure to expose the surface of the fourth groove 14c-4. Laser spots F4, G4, H4, I4 and J4 in the second row are formed in the longitudinal direction.

この場合、２列目の各レーザスポットＦ１，Ｇ１，Ｈ１，Ｉ１，Ｊ１（Ｆ２，Ｇ２，Ｈ２，Ｉ２，Ｊ２、Ｆ３，Ｇ３，Ｈ３，Ｉ３，Ｊ３、Ｆ４，Ｇ４，Ｈ４，Ｉ４，Ｊ４）は１列目の各レーザスポットＡ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１（Ａ２，Ｂ２，Ｃ２，Ｄ２，Ｅ２、Ａ３，Ｂ３，Ｃ３，Ｄ３，Ｅ３、Ａ４，Ｂ４，Ｃ４，Ｄ４，Ｅ４）の溝１４ｃの幅方向の異なる位置で、各レーザスポットの中間部に形成されるようにレーザビーム２−１（２−２、２−３、２−４）を照射するようにしている。   In this case, each laser spot F1, G1, H1, I1, J1 in the second row (F2, G2, H2, I2, J2, F3, G3, H3, I3, J3, F4, G4, H4, I4, J4) Is the groove of each laser spot A1, B1, C1, D1, E1 (A2, B2, C2, D2, E2, A3, B3, C3, D3, E3, A4, B4, C4, D4, E4) in the first row The laser beam 2-1 (2-2, 2-3, 2-4) is irradiated so as to be formed at an intermediate portion of each laser spot at a different position in the width direction 14c.

このようにレーザビーム２−１（２−２、２−３、２−４）を照射することにより、図２（ｂ）に示すように、溝１４ｃの先端部と正極芯体露出部１１ｃとの接合面に溝１４ｃの長手方向に沿って２列目の溶接部ｆ１，ｇ１，ｈ１，ｉ１，ｊ１（ｆ２，ｇ２，ｈ２，ｉ２，ｊ２、ｆ３，ｇ３，ｈ３，ｉ３，ｊ３、ｆ４，ｇ４，ｈ４，ｉ４，ｊ４）がそれぞれ形成される。また、これらの２列目の各溶接部ｆ１，ｇ１，ｈ１，ｉ１，ｊ１（ｆ２，ｇ２，ｈ２，ｉ２，ｊ２、ｆ３，ｇ３，ｈ３，ｉ３，ｊ３、ｆ４，ｇ４，ｈ４，ｉ４，ｊ４）は、それぞれ１列目の各溶接部ａ１，ｂ１，ｃ１，ｄ１，ｅ１（ａ２，ｂ２，ｃ２，ｄ２，ｅ２、ａ３，ｂ３，ｃ３，ｄ３，ｅ３、ａ４，ｂ４，ｃ４，ｄ４，ｅ４）の溝１４ｃの幅方向の異なる位置で、各溶接部の中間部に形成されることとなる。   By irradiating the laser beam 2-1 (2-2, 2-3, 2-4) in this way, as shown in FIG. 2B, the tip of the groove 14c and the positive electrode core exposed portion 11c Along the longitudinal direction of the groove 14c, the second row welds f1, g1, h1, i1, j1 (f2, g2, h2, i2, j2, f3, g3, h3, i3, j3, f4) g4, h4, i4, j4) are formed respectively. Further, the welds f1, g1, h1, i1, j1 (f2, g2, h2, i2, j2, f3, g3, h3, i3, j3, f4, g4, h4, i4, j4) of the second row. ) Are welded parts a1, b1, c1, d1, e1 (a2, b2, c2, d2, e2, a3, b3, c3, d3, e3, a4, b4, c4, d4, e4, respectively). ) At different positions in the width direction of the groove 14c.

これにより、図３（ａ），（ｂ）に示すように、例えば、レーザスポットＡ１（Ａ２〜Ａ４においても同様である）により１〜３巻目の正極芯体露出部１１ｃと溝１４ｃの先端部との接合部に溶接部ａ１（ａ２〜ａ４）が形成されることとなる。同様に、レーザスポットＢ１（Ｂ２〜Ｂ４においても同様である）により１〜３巻目の正極芯体露出部１１ｃと溝１４ｃの先端部との接合部に溶接部ｂ１（ｂ２〜ｂ４）が形成される。そして、レーザスポットＡ１（Ａ２〜Ａ４）とレーザスポットＢ１（Ｂ２〜Ｂ４）との中間部にレーザスポットＦ１（Ｆ２〜Ｆ４）が形成され、このレーザスポットＦ１（Ｆ２〜Ｆ４）により１〜３巻目の正極芯体露出部１１ｃと溝１４ｃの先端部との接合部に溶接部ｆ１（ｆ２〜ｆ４）が形成されることとなる。   Accordingly, as shown in FIGS. 3A and 3B, for example, the first to third turns of the positive electrode core body exposed portion 11c and the tip of the groove 14c by the laser spot A1 (the same applies to A2 to A4). A welded part a1 (a2 to a4) will be formed at the joint with the part. Similarly, a welded portion b1 (b2 to b4) is formed at the joint between the first to third turns of the positive electrode core body exposed portion 11c and the tip of the groove 14c by the laser spot B1 (the same applies to B2 to B4). Is done. And laser spot F1 (F2-F4) is formed in the intermediate part of laser spot A1 (A2-A4) and laser spot B1 (B2-B4), and 1-3 rolls by this laser spot F1 (F2-F4). A welded portion f1 (f2 to f4) is formed at a joint portion between the positive electrode core body exposed portion 11c of the eye and the tip portion of the groove 14c.

この結果、正極芯体露出部１１ｃの全周囲にわたって溶接部ａ１〜ａ４，ｆ１〜ｆ４，ｂ１〜ｂ４，ｇ１〜ｇ４，ｃ１〜ｃ４，ｈ１〜ｈ４，ｄ１〜ｄ４，ｉ１〜ｉ４，ｅ１〜ｅ４，ｊ１〜ｊ４が均等に形成されることとなり、正極板１１の全ての位置で均一に集電することが可能となるので、内部抵抗を低減させることが可能となる。このようにして、正極芯体露出部１１ｃに正極集電体１４が強固に溶接されることとなる。また、渦巻状電極群１０の他端部の負極芯体露出部１２ｃに負極集電体の本体部を押し当てた状態で、上述と同様にレーザビームを照射してレーザスポット溶接を施して、負極芯体露出部１２ｃに負極集電体を溶接することにより電極体が形成されることとなる。   As a result, the welded portions a1 to a4, f1 to f4, b1 to b4, g1 to g4, c1 to c4, h1 to h4, d1 to d4, i1 to i4, and e1 to e4 are provided over the entire periphery of the positive electrode core exposed portion 11c. , J1 to j4 are formed uniformly, and current can be collected uniformly at all positions of the positive electrode plate 11, so that the internal resistance can be reduced. In this way, the positive electrode current collector 14 is firmly welded to the positive electrode core exposed portion 11c. Further, in the state where the main body portion of the negative electrode current collector is pressed against the negative electrode core exposed portion 12c at the other end of the spiral electrode group 10, a laser beam is irradiated in the same manner as described above to perform laser spot welding, An electrode body is formed by welding the negative electrode current collector to the negative electrode core exposed portion 12c.

５．非水電解液二次電池
ついで、上述のように渦巻状電極群１０の上端部に正極集電体１４が溶接され、下端部に負極集電体が溶接された電極体を円筒状の金属製外装缶に挿入する。この後、負極集電体の本体部から延出した負極リードを外装缶の底部内面にスポット溶接した後、正極集電体１４の本体部１４ａから延出した正極リード１４ｅを封口体（なお、この封口体の内部には圧力弁が設けられているとともに周囲に絶縁ガスケットが配設されている：図示せず）の底部にレーザ溶接する。ついで、外装缶内にエチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）を３：７の容積比で混合した混合溶媒に、電解質としてＬｉＰＦ6を１モル／リットルの割合で溶解させた非水電解液を注液した後、封口体を外装缶の開口部の下部周囲に形成された絞り部に配置し、外装缶の開口部を封口体側にかしめて密封することにより、円筒形非水電解液二次電池が作製される。 5. Nonaqueous Electrolyte Secondary Battery Next, the electrode body in which the positive electrode current collector 14 is welded to the upper end portion of the spiral electrode group 10 and the negative electrode current collector is welded to the lower end portion as described above is formed into a cylindrical metal. Insert into the outer can. Thereafter, the negative electrode lead extending from the main body portion of the negative electrode current collector is spot welded to the inner surface of the bottom of the outer can, and then the positive electrode lead 14e extending from the main body portion 14a of the positive electrode current collector 14 is sealed with a sealing body (in addition, A pressure valve is provided inside the sealing body, and an insulating gasket is provided around it (not shown). Laser welding is performed on the bottom of the sealing body. Next, a nonaqueous electrolytic solution in which LiPF 6 as an electrolyte was dissolved at a ratio of 1 mol / liter in a mixed solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 7 in the outer can. After the liquid is injected, the sealing body is placed in a narrowed portion formed around the lower portion of the opening of the outer can, and the opening of the outer can is caulked to the sealing body side to be sealed. A secondary battery is produced.

なお、電解質としては、上述した六フッ化リン酸リチウム（ＬｉＰＦ6）以外に、過塩素酸リチウム（ＬｉＣｌＯ4）、ホウフッ化リチウム（ＬｉＢＦ4）、六フッ化珪酸リチウム（ＬｉＡｓＦ6）、トリフルオロメチルスルホン酸リチウム（ＬｉＣＦ3ＳＯ3）、ビストリフルオロメチルスルホニルイミドリチウム（ＬｉＮ（ＣＦ3ＳＯ2）2）などのリチウム塩を用いるようにしてもよい。また、有機溶媒に対する溶解量としては、１モル／リットルに限らず、０．５〜２．０モル／リットルとするのが好ましい。 As the electrolyte, in addition to the above-described lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium borofluoride (LiBF 4 ), lithium hexafluorosilicate (LiAsF 6 ), trifluoro A lithium salt such as lithium methyl sulfonate (LiCF 3 SO 3 ) or lithium bistrifluoromethylsulfonylimide (LiN (CF 3 SO 2 ) 2 ) may be used. In addition, the amount dissolved in the organic solvent is not limited to 1 mol / liter, but is preferably 0.5 to 2.0 mol / liter.

上述したように、本発明の円筒形電池においては、極板から均一に集電できる集電構造となるようになされているので、内部抵抗の低減した円筒形電池を得ることが可能となるとともに、セパレータに熱的影響を及ぼしたりあるいは短絡が生じることがない円筒形電池を製造方法することが可能となる。   As described above, the cylindrical battery according to the present invention has a current collecting structure capable of collecting current uniformly from the electrode plate, so that a cylindrical battery with reduced internal resistance can be obtained. It is possible to manufacture a cylindrical battery that does not affect the separator thermally or cause a short circuit.

なお、上述した実施の形態においては、レーザ光を照射して渦巻状電極群の両端部に正極集電体と負極集電体を溶接する例について説明したが、レーザ光に代えて、本発明のように電子線や他のエネルギー線を照射して溶接するようにしてもよいことは明らかである。また、上述した実施の形態においては、本発明を非水電解液二次電池に適用する例について説明したが、本発明の円筒形電池は、非水電解液二次電池に限らず、一方の端部に正極芯体露出部が形成され、他方の端部に負極芯体露出部が形成された渦巻状電極群が円筒形外装缶内に収容された電池であれば、ニッケル−水素蓄電池、ニッケル−カドミウム蓄電池などのアルカリ蓄電池やその他の蓄電池に適用できることは明らかである。 In the embodiment described above, an example has been described in which the welding of the positive electrode current collector and the anode current collector at both ends of the spiral electrode group is irradiated with a laser beam, instead of the laser beam, the present invention It is obvious that the welding may be performed by irradiating an electron beam or other energy rays. In the above-described embodiment, the example in which the present invention is applied to a non-aqueous electrolyte secondary battery has been described. However, the cylindrical battery of the present invention is not limited to a non-aqueous electrolyte secondary battery. is positive electrode substrate exposed portion at the end portion is formed, if the battery negative electrode substrate exposed portion is formed a spiral electrode group is accommodated in a cylindrical outer can at the other end, nickel - hydrogen storage battery, It is clear that the present invention can be applied to alkaline storage batteries such as nickel-cadmium storage batteries and other storage batteries.

本発明の渦巻状電極群と正極集電体を模式的に示す斜視図である。The wound electrode group and the positive electrode current collector of the present invention is a perspective view schematically showing. 本発明の渦巻状電極群に正極集電体を溶接する状態を模式的に示す図であり、図２（ａ）は、図１の渦巻状電極群の上に正極集電体を配置してこの正極集電体にレーザを照射した状態を模式的に示す平面図であり、図２（ｂ）はレーザ照射により渦巻状電極群の上に溶接部形成された状態を模式的に示す平面図である。The state of welding the positive electrode current collector to the spiral electrode group of the present invention is a diagram schematically showing, FIG. 2 (a), by placing the positive electrode current collector on the spiral electrode group of FIG. 1 is a plan view showing a state of irradiating a laser beam to the cathode current collector schematically, and FIG. 2 (b) is a plan view of the state of being welded portion formed on the spiral electrode group shown schematically by laser irradiation It is. 図１の渦巻状電極群の正極板と正極集電体との溶接部の形成状態を模式的に示す図であり、図３（ａ）は正極芯体露出部と正極集電体との接触部に溶接部が形成された状態の要部を模式的に示す断面図であり、図３（ｂ）は、渦巻状電極群の正極板の一部を展開して溶接部が形成された状態を模式的に示す図である。Is a diagram schematically illustrating a forming state of the welded portion between the positive electrode plate and the positive electrode current collector of the spiral electrode group of FIG. 1, FIG. 3 (a) is contacted with the positive electrode substrate exposed portion and the positive electrode current collector is a cross-sectional view schematically showing a main portion in a state in which the welded portion is formed in part, FIG. 3 (b), the state in which the welded portion is formed by expanding a portion of the positive electrode plate of the spiral electrode group FIG. 従来例の渦巻状電極群に正極集電タブを溶接する状態を模式的に示す図であり、図４（ａ）は、渦巻状電極群の上に正極集電タブを配置してこの正極集電タブにレーザを照射した状態を模式的に示す平面図であり、図４（ｂ）はレーザ照射により渦巻状電極群の上に溶接部が形成された状態を模式的に示す平面図である。The spiral electrode group of conventional conditions for welding the positive electrode current collector tab is a diagram schematically illustrating, FIG. 4 (a), the positive electrode by disposing a positive electrode current collector tabs on the spiral electrode group and a state of irradiating a laser beam to collector tab a plan view schematically illustrating, FIG. 4 (b) is a plan view showing a state in which the welded portion is formed on the spiral electrode group by laser irradiation schematically . 図４の渦巻状電極群の正極板と正極集電タブとの溶接部の形成状態を模式的に示す図であり、図５（ａ）は正極芯体露出部と正極集電タブとの接触部に溶接部が形成された状態の要部を模式的に示す断面図であり、図５（ｂ）は、渦巻状電極群の正極板の一部を展開して溶接部が形成された状態を模式的に示す図である。Is a diagram schematically illustrating a forming state of the welded portion between the positive electrode plate and the positive electrode current collector tab of the spiral electrode group of FIG. 4, FIG. 5 (a) contacting the positive electrode substrate exposed portion and the positive electrode current collector tab is a cross-sectional view schematically showing a main portion in a state in which the welded portion is formed in part, FIG. 5 (b), the state in which the welded portion is formed by expanding a portion of the positive electrode plate of the spiral electrode group FIG.

符号の説明Explanation of symbols

１０…渦巻状電極群、１１…正極板、１１ａ…正極芯体、１１ｂ…正極合剤層、１１ｃ…正極芯体露出部、１２…負極板、１２ａ…負極芯体、１２ｂ…負極合剤層、１２ｃ…負極芯体露出部、１３…セパレータ、１４…正極集電体、１４ａ…本体部、１４ｂ…中心開口、１４ｃ…溝、１４ｄ…注液孔、１４ｅ…正極リード
DESCRIPTION OF SYMBOLS 10 ... Spiral electrode group, 11 ... Positive electrode plate, 11a ... Positive electrode core, 11b ... Positive electrode mixture layer, 11c ... Positive electrode core exposed part, 12 ... Negative electrode plate, 12a ... Negative electrode core, 12b ... Negative electrode mixture layer , 12c ... negative electrode core exposed part, 13 ... separator, 14 ... positive electrode current collector, 14a ... main body part, 14b ... central opening, 14c ... groove, 14d ... liquid injection hole, 14e ... positive electrode lead

Claims (6)

渦巻状電極群の巻軸方向の一方端部に位置する渦巻状の正極芯体露出部の端面に正極集電体が溶接され、前記渦巻状電極群の巻軸方向の他方端部に位置する渦巻状の負極芯体露出部の端面に負極集電体が溶接された電極体を円筒形外装缶内に備えた円筒形電池であって、
前記正極集電体および前記負極集電体の少なくとも一方は中心開口と当該中心開口から放射状に形成された溝部とを備えており、
前記溝部の幅方向に少なくとも２列以上の当該溝部の長さ方向に沿ったエネルギー線の照射により当該溝部と前記芯体露出部との接触部で前記エネルギー線の照射位置に溶接部が形成されており、
前記溶接部は前記溝部の幅方向に少なくとも２列以上で当該溝部の長さ方向に沿って不連続な溶接部列となるように形成されているとともに、
前記溶接部列の１列目に形成された不連続な各溶接部の間で当該第１列目とは前記溝部の幅方向に異なる位置に２列目以降に形成された不連続な各溶接部が形成されていることを特徴とする円筒形電池。 A positive electrode current collector is welded to the end surface of the spiral positive electrode core exposed portion located at one end portion in the winding axis direction of the spiral electrode group, and is positioned at the other end portion in the winding axis direction of the spiral electrode group. A cylindrical battery comprising an electrode body in which a negative electrode current collector is welded to an end face of a spiral negative electrode core exposed portion in a cylindrical outer can,
At least one of the positive electrode current collector and the negative electrode current collector includes a center opening and a groove formed radially from the center opening,
By irradiating energy beams along the length direction of at least two rows of the groove portions in the width direction of the groove portions, weld portions are formed at the irradiation positions of the energy rays at the contact portions between the groove portions and the core body exposed portions. And
The welded portion is formed so as to be a discontinuous welded portion row along the length direction of the groove portion in at least two rows or more in the width direction of the groove portion,
Discontinuous welds formed in the second and subsequent rows at different positions in the width direction of the groove between the discontinuous welds formed in the first row of the weld row. A cylindrical battery in which a portion is formed. 前記溝部は断面形状が略Ｕ字状で前記中心開口から互に直角となる４方向に形成されていて、当該溝部と前記芯体露出部との接触部に前記溶接部が形成されていることを特徴とする請求項１に記載の円筒形電池。   The groove portion has a substantially U-shaped cross section and is formed in four directions perpendicular to each other from the central opening, and the weld portion is formed at a contact portion between the groove portion and the core body exposed portion. The cylindrical battery according to claim 1. 前記中心開口と当該中心開口から放射状に形成された溝部とを備えた集電体は１つの部材により形成されていることを特徴とする請求項１または請求項２に記載の円筒形電池。   3. The cylindrical battery according to claim 1, wherein the current collector including the center opening and a groove formed radially from the center opening is formed by a single member. 前記中心開口と当該中心開口から放射状に形成された溝部とを備えた集電体の本体部は略円板状に形成されていることを特徴とする請求項１から請求項３のいずれかに記載の円筒形電池。   4. The main body portion of the current collector including the central opening and a groove formed radially from the central opening is formed in a substantially disc shape. 5. The cylindrical battery as described. 渦巻状電極群の巻軸方向の一方端部に位置する渦巻状の正極芯体露出部の端面に正極集
電体を溶接するとともに、前記渦巻状電極群の巻軸方向の他方端部に位置する渦巻状の負極芯体露出部の端面に負極集電体を溶接した電極体を円筒形外装缶内に収容して形成する円筒形電池の製造方法であって、
前記正極集電体および前記負極集電体の少なくとも一方は中心開口と当該中心開口から放射状に形成された溝部とを備えており、
前記溝部の長さ方向に沿った列に並ぶ不連続な溶接部が形成されるように前記溝部の長さ方向に沿って第１列目のエネルギー線を照射する第１列目エネルギー線照射工程と、
第２列目以降のエネルギー線の照射により形成された前記溝部の長さ方向に沿った列に並ぶ不連続な溶接部が前記第１列目のエネルギー線の照射により形成された前記溝部の長さ方向に沿った列に並ぶ不連続な溶接部の間に形成されるように前記第１列目とは前記溝部の幅方向に異なる位置に第２列目以降のエネルギー線を照射する第２列目以降エネルギー線照射工程とを備えたことを特徴とする円筒形電池の製造方法。 A positive electrode current collector is welded to the end face of the spiral positive electrode core exposed portion located at one end portion in the winding axis direction of the spiral electrode group, and is positioned at the other end portion in the winding axis direction of the spiral electrode group A cylindrical battery manufacturing method for forming an electrode body in which a negative electrode current collector is welded to an end face of a spiral negative electrode core exposed portion in a cylindrical outer can,
At least one of the positive electrode current collector and the negative electrode current collector includes a center opening and a groove formed radially from the center opening,
A first-row energy beam irradiation step of irradiating a first-row energy beam along the length direction of the groove portion so as to form discontinuous welds arranged in a row along the length direction of the groove portion. When,
The length of the groove formed by the irradiation of the second row and subsequent energy ray irradiation discontinuous welds the first column of the energy beam arranged in rows along the length of the formed said groove by the A second irradiation of the second row and subsequent energy rays is performed at a position different from the first row in the width direction of the groove so as to be formed between discontinuous welds arranged in rows along the vertical direction . A method for producing a cylindrical battery, comprising: an energy beam irradiation step after the row. 前記エネルギー線はレーザ光であることを特徴とする請求項５に記載の円筒形電池の製造方法。

6. The method for manufacturing a cylindrical battery according to claim 5, wherein the energy beam is a laser beam.

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