JP4428965B2

JP4428965B2 - Battery unit

Info

Publication number: JP4428965B2
Application number: JP2003301610A
Authority: JP
Inventors: 広一佐藤; 直哉中西; 隆明池町; 俊之能間
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 2003-08-26
Filing date: 2003-08-26
Publication date: 2010-03-10
Anticipated expiration: 2023-08-26
Also published as: JP2005071862A

Description

本発明は、リチウムイオン二次電池の如く、電池缶の内部に発電要素となる電極体が収容され、該電極体が発生する電力を正負一対の電極端子部から外部に取り出すことが出来る電池、並びに該電池を直列に接続してなる電池ユニットに関するものである。 The present invention, like a lithium ion secondary battery, an electrode body serving as a power generation element is housed inside a battery can, and the power generated by the electrode body can be taken out from a pair of positive and negative electrode terminal portions, The present invention also relates to a battery unit formed by connecting the batteries in series.

近年、携帯型電子機器、電気自動車などの電源として、エネルギー密度の高いリチウムイオン二次電池が注目されている。
例えば特許文献１に示すリチウムイオン二次電池は、図９に示す如く、底壁(97)及び周壁(96)を有する円筒状の負極缶(91)の内部に巻き取り電極体(４)を収容して、負極缶(91)の開口部に封口体(２)を固定したものであって、負極缶(91)と封口体(２)の間には絶縁部材(12)が介在している。封口体(２)は、中央孔(21a)が開設された蓋(21)と、該中央孔(21a)を覆う円筒状のキャップ(22)とを具え、蓋(21)の裏面には、前記中央孔(21a)と対向する位置に弁体(24)を具えた金属薄膜(25)が配備され、キャップ(22)の外周面には複数のガス排出孔(23)が開設されている。又、キャップ(22)によって正極端子部(20)が構成され、負極缶(91)の底壁(97)によって負極端子部(90)が構成されている。
尚、負極缶(91)は、ニッケル鍍金を施した鉄製である。 In recent years, lithium ion secondary batteries with high energy density have attracted attention as power sources for portable electronic devices and electric vehicles.
For example, in the lithium ion secondary battery shown in Patent Document 1, as shown in FIG. 9, a winding electrode body (4) is provided inside a cylindrical negative electrode can (91) having a bottom wall (97) and a peripheral wall (96). The sealing body (2) is fixed to the opening of the negative electrode can (91), and an insulating member (12) is interposed between the negative electrode can (91) and the sealing body (2). Yes. The sealing body (2) includes a lid (21) having a central hole (21a) and a cylindrical cap (22) covering the central hole (21a). A metal thin film (25) having a valve body (24) is provided at a position facing the central hole (21a), and a plurality of gas discharge holes (23) are opened on the outer peripheral surface of the cap (22). . The cap (22) constitutes the positive electrode terminal part (20), and the bottom wall (97) of the negative electrode can (91) constitutes the negative electrode terminal part (90).
The negative electrode can (91) is made of iron with nickel plating.

巻き取り電極体(４)は、それぞれ帯状の正極(41)、セパレータ(42)及び負極(43)から構成され、正極(41)及び負極(43)はそれぞれセパレータ(42)上に幅方向へずらして重ね合わされ、渦巻状に巻き取られている。これによって、巻き取り電極体(４)の軸方向の両端部の内、一方の端部では、セパレータ(42)の端縁よりも外方へ正極(41)の端縁が突出すると共に、他方の端縁では、セパレータ(42)の端縁よりも外方へ負極(43)の端縁が突出している。 The take-up electrode body (4) is composed of a strip-like positive electrode (41), a separator (42) and a negative electrode (43), respectively. The positive electrode (41) and the negative electrode (43) are arranged in the width direction on the separator (42). They are overlapped and wound up in a spiral shape. As a result, the end edge of the positive electrode (41) protrudes outward from the end edge of the separator (42) at one end portion of both ends in the axial direction of the winding electrode body (4), and the other end At the edge, the edge of the negative electrode (43) protrudes outward from the edge of the separator (42).

巻き取り電極体(４)の両端部にはそれぞれ集電板(３)(30)が設置されている。正極側の集電板(３)は、巻き取り電極体(４)の貫通孔(410)と対向する位置に中央孔(34)が形成され、リード(35)の先端が封口体(２)の金属薄膜(25)にレーザ溶接されて正極端子部(20)に接続されている。又、負極側の集電板(30)は、本体(31)の中心部が負極缶(91)の底壁(97)にスポット溶接されて負極端子部(90)に接続されており、これによって、巻き取り電極体(４)が発生する電力を正極端子部(20)と負極端子部(90)から外部へ取り出すことが出来る。 Current collector plates (3) and (30) are installed at both ends of the winding electrode body (4). The current collector plate (3) on the positive electrode side is formed with a central hole (34) at a position facing the through hole (410) of the winding electrode body (4), and the tip of the lead (35) is the sealing body (2). The metal thin film (25) is laser welded and connected to the positive terminal (20). The current collector plate (30) on the negative electrode side is spot welded to the bottom wall (97) of the negative electrode can (91) at the center of the main body (31) and connected to the negative electrode terminal portion (90). Thus, the electric power generated by the winding electrode body (4) can be taken out from the positive terminal portion (20) and the negative terminal portion (90).

又、複数本の電池を直列に接続するために、図１０に示す如きジョイントキャップ(６)を用いることが知られている(例えば特許文献２及び特許文献３参照)。
該ジョイントキャップ(６)は、互いに直列に接続すべき２本の電池(9a)(9b)の間に介在するものであって、一方の電池(9b)の負極缶(91)の底部を包囲すべき円筒状の第１接続部(61)と、他方の電池(9a)のキャップ(22)を包囲すべき円筒状の第２接続部(62)とから構成され、第１接続部(61)の内周面には、負極缶(91)の周壁(96)に向かって突出する複数の第１プロジェクション(65)が形成されると共に、第２接続部(62)の底面には、封口体(２)に向かって突出する複数の第２プロジェクション(66)が形成されている。 Further, it is known to use a joint cap (6) as shown in FIG. 10 in order to connect a plurality of batteries in series (see, for example, Patent Document 2 and Patent Document 3).
The joint cap (6) is interposed between two batteries (9a) (9b) to be connected in series with each other, and surrounds the bottom of the negative electrode can (91) of one battery (9b). A cylindrical first connection part (61) to be formed and a cylindrical second connection part (62) to surround the cap (22) of the other battery (9a). ) Is formed with a plurality of first projections (65) protruding toward the peripheral wall (96) of the negative electrode can (91), and the bottom surface of the second connection part (62) A plurality of second projections (66) projecting toward the body (2) are formed.

２本の電池(9a)(9b)を直列に接続する場合には、先ず、前記他方の電池(9a)の封口体(２)の蓋(21)の表面にジョイントキャップ(６)を設置し、該ジョンインキャップ(６)の第２プロジェクション(66)を蓋(21)の表面に抵抗溶接若しくはレーザ溶接する。次に、該ジョイントキャップ(６)上に前記一方の電池(9b)を設置し、ジョイントキャップ(６)の第１プロジェクション(65)を負極缶(91)の外周面に抵抗溶接若しくはレーザ溶接する。
この様にして、２本以上の電池を直列に接続することによって、所望の電力や電圧を得ることの出来る電池ユニットが構成される。
特開２００２−１３４０９５号公報[H01M2/26] 特開２００１−３５４７３号公報[H01M2/20] 特開２０００−７７０５２号公報[H01M2/20] When two batteries (9a) and (9b) are connected in series, first, a joint cap (6) is installed on the surface of the lid (21) of the sealing body (2) of the other battery (9a). The second projection (66) of the John-in cap (6) is resistance-welded or laser-welded to the surface of the lid (21). Next, the one battery (9b) is installed on the joint cap (6), and the first projection (65) of the joint cap (6) is resistance welded or laser welded to the outer peripheral surface of the negative electrode can (91). .
Thus, the battery unit which can obtain desired electric power and voltage is comprised by connecting two or more batteries in series.
JP 2002-134095 A [H01M2 / 26] JP 2001-35473 A [H01M2 / 20] JP 2000-77052 A [H01M2 / 20]

ところで、複数のリチウムイオン二次電池を直列に接続して構成される電池ユニットの出力を増大させるためには、互いに直列に接続した電池間に生じる電気抵抗を小さくすることが有効であり、図１０に示す電池ユニットにおいては、ジョイントキャップ(６)の第１プロジェクション(65)と前記一方の電池(9b)の周壁(96)との溶接部の電気抵抗を低減させることが有効である。そこで、溶接部を形成すべき第１プロジェクション(65)と周壁(96)の接触面に従来よりも大きな溶接熱を発生させ、該溶接熱によって第１プロジェクション(65)の溶け込み量を増大させることにより溶接部の面積を増大させ、これによって溶接部の電気抵抗を低減させることが考えられる。 By the way, in order to increase the output of a battery unit configured by connecting a plurality of lithium ion secondary batteries in series, it is effective to reduce the electric resistance generated between the batteries connected in series. In the battery unit shown in FIG. 10, it is effective to reduce the electrical resistance of the welded portion between the first projection (65) of the joint cap (6) and the peripheral wall (96) of the one battery (9b). Therefore, a larger welding heat is generated at the contact surface between the first projection (65) and the peripheral wall (96) where a weld is to be formed, and the amount of penetration of the first projection (65) is increased by the welding heat. It is conceivable to increase the area of the welded portion by this, thereby reducing the electrical resistance of the welded portion.

しかしながら、図９に示すリチウムイオン二次電池においては、所望のエネルギー密度を確保するために、負極缶(91)は例えば厚さ０.５ｍｍの金属板をプレス成型することにより形成されているので、周壁(96)の厚さは薄く、その単位面積当りの熱容量は小さいものとなっている。このため、ジョイントキャップ(６)を電池缶に溶接接合するときに第１プロジェクション(65)と周壁(96)の接触面に従来よりも大きな溶接熱を発生させると、該熱が周壁(96)側の溶接部及びその周囲に伝わってこれらの部分の温度が急激に上昇し、ニッケル鍍金が損傷する虞があった。
そこで本発明の目的は、従来よりも大きな溶接熱でジョイントキャップと缶本体とを溶接することが出来る筒型二次電池及びこれを用いた電池ユニットを提供することである。 However, in the lithium ion secondary battery shown in FIG. 9, in order to ensure a desired energy density, the negative electrode can (91) is formed by press-molding a metal plate having a thickness of 0.5 mm, for example. The peripheral wall (96) is thin, and its heat capacity per unit area is small. For this reason, when welding heat larger than that in the prior art is generated on the contact surface between the first projection (65) and the peripheral wall (96) when the joint cap (6) is welded to the battery can, the heat is applied to the peripheral wall (96). There was a risk that the temperature of these parts would rise suddenly along the welded part on the side and its surroundings, resulting in damage to the nickel plating.
Accordingly, an object of the present invention is to provide a cylindrical secondary battery capable of welding a joint cap and a can body with a larger welding heat than before and a battery unit using the same.

本発明に係る電池ユニットは、電池本体の両端部に一対の電極端子部が設けられている複数本の電池を直列に接続して構成され、連続する２本の電池(1a)(1b)の間にはジョイントキャップ(６)が介在している。The battery unit according to the present invention is formed by connecting a plurality of batteries each having a pair of electrode terminal portions provided at both ends of the battery body in series, and includes two continuous batteries (1a) (1b). A joint cap (6) is interposed between them.
前記電池は、筒状の缶本体(11)の開口部に封口体(２)を取り付けてなる電池缶(１)を具え、該電池缶(１)の内部には二次電池要素が収容され、該二次電池要素が発生する電力を正負一対の電極端子部(10)(20)から外部に取り出すことが可能である。前記缶本体(11)は、筒状の周壁(16)と該周壁(16)の一方の開口を塞ぐ底壁とを一体成型して構成されており、該底壁によって一方の電極端子部(10)が構成されると共に、前記封口体(２)によって他方の電極端子部(20)が構成され、前記周壁(16)は、底壁側の厚肉周壁部(13)と封口体(２)側の薄肉周壁部(14)とから構成されている。 The battery includes a battery can (1) having a sealing body (2) attached to an opening of a cylindrical can body (11), and a secondary battery element is accommodated in the battery can (1). The electric power generated by the secondary battery element can be taken out from the pair of positive and negative electrode terminal portions (10) and (20). The can body (11) is formed by integrally molding a cylindrical peripheral wall (16) and a bottom wall that closes one opening of the peripheral wall (16), and one electrode terminal portion ( 10), and the sealing body (2) constitutes the other electrode terminal portion (20). The peripheral wall (16) has a thick peripheral wall portion (13) on the bottom wall side and a sealing body (2 ) Side thin peripheral wall portion (14).
前記ジョイントキャップ(６)は、第１の電池(1b)の缶本体(11)の底壁に接触すべき第１接続部(61)と、第２の電池(1a)の封口体(２)に接触すべき第２接続部(62)とにより構成されている。前記第１接続部(61)は、第１の電池(1b)の缶本体(11)の底壁と対向する平板部(63)と、該平板部(63)の外周縁に突設されて第１の電池(1b)の缶本体(11)の周壁(16)を包囲する筒状のスカート部(64)とを具え、該スカート部(64)は、第１の電池(1b)の周壁(16)の厚肉周壁部(13)に溶接されている。 The joint cap (6) includes a first connecting part (61) to be in contact with the bottom wall of the can body (11) of the first battery (1b) and a sealing body (2) of the second battery (1a). And a second connection portion (62) to be in contact with the. The first connection part (61) is provided so as to project from a flat plate part (63) facing the bottom wall of the can body (11) of the first battery (1b) and an outer peripheral edge of the flat plate part (63). A cylindrical skirt (64) surrounding the peripheral wall (16) of the can body (11) of the first battery (1b), the skirt (64) being a peripheral wall of the first battery (1b) It is welded to the thick peripheral wall (13) of (16).

本発明に係る電池ユニットによれば、ジョイントキャップ(６)と第１の電池(1b)の溶接接合部を形成すべき前記第１接続部(61)と厚肉周壁部(13)の接触面に、従来よりも大きな溶接熱を発生させることが出来、これによって、ジョイントキャップ(６)の溶け込み量を増大させて溶接接合部の面積を増大させることが出来る。According to the battery unit of the present invention, the contact surface between the first connecting part (61) and the thick peripheral wall part (13) to form the welded joint part between the joint cap (6) and the first battery (1b). In addition, it is possible to generate larger welding heat than in the past, thereby increasing the amount of penetration of the joint cap (6) and increasing the area of the weld joint.

また、本発明の電池ユニットに係る筒型二次電池においては、筒状の缶本体(11)の開口部に封口体(２)を取り付けてなる電池缶(１)の内部に二次電池要素が収容され、該二次電池要素が発生する電力を正負一対の電極端子部(10)(20)から外部に取り出すことが出来る。前記缶本体(11)は、筒状の周壁(16)と該周壁(16)の一方の開口を塞ぐ底壁とを一体成型して構成されており、該底壁によって一方の電極端子部(10)が構成され、前記周壁(16)は、底壁側の厚肉周壁部(13)と封口体(２)側の薄肉周壁部(14)とから構成されている。Further, in the cylindrical secondary battery according to the battery unit of the present invention, the secondary battery element is provided inside the battery can (1) in which the sealing body (2) is attached to the opening of the cylindrical can body (11). And the electric power generated by the secondary battery element can be taken out from the pair of positive and negative electrode terminal portions (10) and (20). The can body (11) is formed by integrally molding a cylindrical peripheral wall (16) and a bottom wall that closes one opening of the peripheral wall (16), and one electrode terminal portion ( 10), and the peripheral wall (16) includes a thick peripheral wall portion (13) on the bottom wall side and a thin peripheral wall portion (14) on the sealing body (2) side.

上記筒型二次電池によれば、周壁(16)の厚肉周壁部(13)は、薄肉周壁部(14)と比べて単位面積当り十分に大きな熱容量を有している。従って、缶本体(11)とジョイントキャップを溶接接合する場合、厚肉周壁部(13)とジョイントキャップの接触面には、薄肉周壁部(14)と同一厚さを有する従来の周壁とジョイントキャップの接触面よりも大きな溶接熱を発生させることが出来、該溶接熱によって厚肉周壁部(13)が損傷を受けることはない。従って、厚肉周壁部(13)とジョイントキャップの溶接部に大きな溶接熱を発生させてジョイントキャップの溶け込み量を増大させることが出来、溶接部の面積を増大させることが出来る。According to the cylindrical secondary battery, the thick peripheral wall portion (13) of the peripheral wall (16) has a sufficiently large heat capacity per unit area as compared with the thin peripheral wall portion (14). Therefore, when welding the can body (11) and the joint cap, the conventional peripheral wall and joint cap having the same thickness as the thin peripheral wall portion (14) are formed on the contact surface of the thick peripheral wall portion (13) and the joint cap. It is possible to generate welding heat larger than that of the contact surface, and the thick peripheral wall portion (13) is not damaged by the welding heat. Therefore, a large welding heat can be generated in the thick wall portion (13) and the welded portion of the joint cap to increase the amount of penetration of the joint cap, and the area of the welded portion can be increased.

具体的構成において、前記二次電池要素は、それぞれ帯状の正極(41)と負極(43)の間にセパレータ(42)を介在させてこれらを渦巻状に巻き取った巻き取り電極体(４)を具え、正極(41)及び負極(43)はそれぞれ、帯状芯体の表面に活物質を塗布して構成されている。前記巻き取り電極体(４)の何れか一方の端部には、正極(41)或いは負極(43)を構成する帯状芯体の端縁が突出し、該端縁を覆って集電板(30)が設置され、該集電板(30)が前記底壁に溶接されており、前記周壁(16)の厚肉周壁部(13)の内周面は、薄肉内周壁(14)の内周面よりも内側に突出し、巻き取り電極体(４)の外周面と対向しており、厚肉周壁部(13)と薄肉周壁部(14)との間には、両周壁部(13)(14)の内周面を繋ぐテーパ面(15)が形成されている。In a specific configuration, the secondary battery element includes a take-up electrode body (4) in which a separator (42) is interposed between a belt-like positive electrode (41) and a negative electrode (43), and these are wound in a spiral shape. Each of the positive electrode (41) and the negative electrode (43) is configured by applying an active material to the surface of the belt-like core. An edge of a strip-shaped core constituting the positive electrode (41) or the negative electrode (43) protrudes at one end of the winding electrode body (4), and covers the edge to collect a current collector plate (30 ) And the current collector plate (30) is welded to the bottom wall, and the inner peripheral surface of the thick peripheral wall portion (13) of the peripheral wall (16) is the inner peripheral surface of the thin inner peripheral wall (14). It protrudes inward from the surface and faces the outer peripheral surface of the winding electrode body (4). Between the thick peripheral wall portion (13) and the thin peripheral wall portion (14), both peripheral wall portions (13) ( A tapered surface (15) connecting the inner peripheral surfaces of 14) is formed.

該具体的構成においては、電池組立工程にて、前記テーパ面(15)の案内によって巻き取り電極体(４)を缶本体(11)の奥方に挿入することが出来るので、巻き取り電極体(４)の端縁に設置された集電板(30)を底壁に設置する作業を容易に行なうことが出来ると共に、集電板(30)を底壁の所定の位置に正確に設置することが出来る。従って、集電板(30)を底壁の所定の位置に溶接する作業を確実に行なうことが出来る。In the specific configuration, in the battery assembly process, the winding electrode body (4) can be inserted into the back of the can body (11) by guiding the tapered surface (15). 4) It is possible to easily perform the work of installing the current collector plate (30) installed at the edge of the bottom wall on the bottom wall, and to accurately install the current collector plate (30) at a predetermined position on the bottom wall. I can do it. Therefore, the operation of welding the current collector plate (30) to a predetermined position on the bottom wall can be reliably performed.

他の具体的構成において、前記底壁は、前記周壁(16)の厚肉周壁部(13)と同一若しくは略同一の厚さを有する厚肉底壁(17a)によって形成されている。In another specific configuration, the bottom wall is formed by a thick bottom wall (17a) having the same or substantially the same thickness as the thick peripheral wall portion (13) of the peripheral wall (16).
該具体的構成においては、厚肉底壁(17a)が従来の底壁よりも十分に大きい単位面積当たりの熱容量を有することになるので、厚肉底壁(17a)と集電板(30)の接触面に大きな溶接熱を発生させた場合にも、該溶接熱によって厚肉底壁(17a)が損傷を受けることはない。従って、厚肉底壁(17a)と集電板(30)の溶接部に従来よりも大きな溶接熱を発生させて集電板(30)の溶け込み量を増大させることが出来、これによって溶接部の面積を増大させることが出来る。 In the specific configuration, the thick bottom wall (17a) has a sufficiently larger heat capacity per unit area than the conventional bottom wall, so the thick bottom wall (17a) and the current collector plate (30) Even when large welding heat is generated on the contact surface, the thick bottom wall (17a) is not damaged by the welding heat. Accordingly, it is possible to increase the amount of penetration of the current collector plate (30) by generating larger welding heat than before in the welded portion of the thick-walled bottom wall (17a) and the current collector plate (30). Can be increased.

本発明の電池ユニットによれば、従来よりも大きな溶接熱でジョイントキャップと缶本体とを溶接することが出来、電池とジョイントキャップとの溶接接合部の面積を従来よりも増大させることが出来る。
According to the battery unit of the present invention , the joint cap and the can body can be welded with larger welding heat than before, and the area of the welded joint between the battery and the joint cap can be increased as compared with the conventional case .

以下、本発明を実施した形態につき、図面に沿って具体的に説明する。
円筒型リチウムイオン二次電池
全体構成
本発明に係る電池ユニットの円筒型リチウムイオン二次電池において、電池缶(１)は、図１及び図２に示す如く、缶本体(11)の開口部に円板状の封口体(２)を固定したものであって、該電池缶(１)の内部には、巻き取り電極体(４)が収容されている。又、封口体(２)のキャップ(22)によって正極端子部(20)が構成されると共に、缶本体(11)の底壁(17)によって負極端子部(10)が構成されている。
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
Cylindrical lithium ion secondary battery
Overall Configuration In the cylindrical lithium ion secondary battery of the battery unit according to the present invention, the battery can (1) has a disk-like sealing body (11) at the opening of the can body (11) as shown in FIGS. 2) is fixed, and a winding electrode body (4) is accommodated in the battery can (1). The positive terminal portion (20) is constituted by the cap (22) of the sealing body (2), and the negative electrode terminal portion (10) is constituted by the bottom wall (17) of the can body (11).

巻き取り電極体(４)の両端部にはそれぞれ集電板(３)(30)が設置され、両集電板(３)(30)が巻き取り電極体(４)にレーザ溶接により接合されている。正極側の集電板(３)のリード(35)の先端は、封口体(２)の金属薄膜(25)にレーザ溶接によって接合されており、これによって正極側の集電板(３)は正極端子部(20)に接続されている。又、負極側の集電板(30)の本体(31)は、その中心部が缶本体(11)の底壁(17)に抵抗溶接されており、これによって負極側の集電板(30)は負極端子部(10)に接続されている。この結果、巻き取り電極体(４)が発生する電力を正極端子部(20)と負極端子部(10)から外部へ取り出すことが出来る。 Current collector plates (3) and (30) are installed at both ends of the winding electrode body (4), and both current collector plates (3) and (30) are joined to the winding electrode body (4) by laser welding. ing. The tip of the lead (35) of the positive current collector (3) is joined to the metal thin film (25) of the sealing body (2) by laser welding, so that the positive current collector (3) is Connected to the positive terminal (20). The main body (31) of the negative current collector plate (30) is resistance-welded at its center to the bottom wall (17) of the can main body (11), whereby the negative current collector plate (30 ) Is connected to the negative terminal portion (10). As a result, the electric power generated by the winding electrode body (4) can be taken out from the positive terminal portion (20) and the negative terminal portion (10).

巻き取り電極体(４)
巻き取り電極体(４)は、図３に示す如く、それぞれ帯状の正極(41)と負極(43)の間に帯状のセパレータ(42)を介在させて、これらを渦巻き状に巻回して構成されている。正極(41)は、アルミニウム箔からなる帯状芯体(45)の両面にリチウム複合酸化物からなる正極活物質(44)を塗布して構成され、負極(43)は、銅箔からなる帯状芯体(47)の両面に炭素材料を含む負極活物質(46)を塗布して構成されている。又、セパレータ(42)には、非水電解液が含浸されている。 Winding electrode body (4)
As shown in FIG. 3, the wound electrode body (4) is formed by interposing a strip-shaped separator (42) between a strip-shaped positive electrode (41) and a negative electrode (43) and winding them in a spiral shape. Has been. The positive electrode (41) is configured by applying a positive electrode active material (44) made of a lithium composite oxide on both surfaces of a belt-like core (45) made of an aluminum foil, and the negative electrode (43) is made of a belt-like core made of a copper foil. The negative electrode active material (46) containing a carbon material is applied to both surfaces of the body (47). The separator (42) is impregnated with a non-aqueous electrolyte.

正極(41)には、正極活物質(44)の塗布されている塗工部と、正極活物質の塗布されていない非塗工部とが形成されている。又、負極(43)にも、負極活物質(46)の塗布されている塗工部と、負極活物質の塗布されていない非塗工部とが形成されている。
正極(41)及び負極(43)は、それぞれセパレータ(42)上に幅方向へずらして重ね合わせ、正極(41)及び負極(43)の前記非塗工部をセパレータ(42)の両端縁からそれぞれ外側へ突出させる。そして、これらを渦巻き状に巻き取ることによって巻き取り電極体(４)が構成される。該巻き取り電極体(４)においては、巻き軸方向の両端部の内、一方の端部では、正極(41)の非塗工部の芯体端縁(48a)が、セパレータ(42)の一方の端縁よりも外方へ突出し、他方の端部では、負極(43)の非塗工部の芯体端縁(48b)が、セパレータ(42)の他方の端縁よりも外方へ突出している。 The positive electrode (41) is formed with a coated portion where the positive electrode active material (44) is applied and a non-coated portion where the positive electrode active material is not applied. The negative electrode (43) is also formed with a coated portion where the negative electrode active material (46) is applied and a non-coated portion where the negative electrode active material is not applied.
The positive electrode (41) and the negative electrode (43) are respectively superimposed on the separator (42) while being shifted in the width direction, and the uncoated portions of the positive electrode (41) and the negative electrode (43) are separated from both end edges of the separator (42). Each protrudes outward. And a winding electrode body (4) is comprised by winding up these in the shape of a spiral. In the wound electrode body (4), the core body edge (48a) of the non-coated portion of the positive electrode (41) is at one end of both ends in the winding axis direction of the separator (42). Projecting outward from one edge, the core edge (48b) of the non-coated part of the negative electrode (43) is outward from the other edge of the separator (42) at the other edge. It protrudes.

集電構造
正極側の集電板(３)は、図３及び図４に示す如く円板状の本体(31)と該本体(31)の外周縁に突設された帯状のリード(35)とから構成されており、前記本体(31)には、中央孔(34)が開設されている。又、本体(31)には、中央孔(34)を中心として放射状に伸びる複数条(実施例では４条)の円弧状凸部(32)が一体成型され、巻き取り電極体(４)側に突出している。該円弧状凸部(32)は、図５(ａ)に示す如く前記本体(31)の半径線に直交する断面形状が半円の円弧状を呈している。
又、前記本体(31)には、隣接する円弧状凸部(32)(32)の間にそれぞれ、図５(ｂ)に示す複数条(実施例では２条)の切り起し片(33)が形成され、前記巻き取り電極体(４)側に突出している。該切り起し片(33)の切り起こしに伴って形成された貫通孔は、後述の組立工程にて巻き取り電極体(４)に電解液を含浸させる際の電解液の通路となる。
尚、負極側の集電板(30)は、リード(35)及び中央孔(34)を具えていないことを除いて正極側の集電板(３)と同一構造を有している。 As shown in FIGS. 3 and 4, the current collecting plate (3) on the current collecting structure positive electrode side has a disc-shaped main body (31) and a strip-shaped lead (35) protruding from the outer peripheral edge of the main body (31). A central hole (34) is formed in the main body (31). Further, the main body (31) is integrally formed with a plurality of arcuate convex portions (32) extending radially around the central hole (34), and the winding electrode body (4) side. Protruding. As shown in FIG. 5 (a), the arc-shaped convex portion (32) has an arc shape with a semicircular cross section perpendicular to the radial line of the main body (31).
Further, the main body (31) includes a plurality of (two in the embodiment) cut and raised pieces (33 in the embodiment) shown in FIG. 5B between the adjacent arc-shaped convex portions (32) and (32). ) And protrudes toward the take-up electrode body (4). The through hole formed as the cut and raised piece (33) is cut and raised serves as a passage for the electrolytic solution when the winding electrode body (4) is impregnated with the electrolytic solution in the assembly process described later.
The current collector plate (30) on the negative electrode side has the same structure as the current collector plate (3) on the positive electrode side, except that the lead (35) and the central hole (34) are not provided.

電池缶(１)
図１及び図２に示す如く、電池缶(１)は、円筒状の缶本体(11)の開口部に円板状の封口体(２)を固定して構成され、缶本体(11)と封口体(２)の間には絶縁部材(12)が介在している。缶本体(11)は、円筒状の周壁(16)と該周壁(16)の一方の開口を塞ぐ円板状の底壁(17)とを一体成型して構成されており、周壁(16)は、底壁(17)側の厚肉周壁部(13)と封口体(２)側の薄肉周壁部(14)とから構成されている。厚肉周壁部(13)の内周面は、薄肉内周壁(14)の内周面よりも内側に突出し、巻き取り電極体(４)の負極芯体によって構成される円筒状突部(49)の外周面との間に僅かな隙間を有して対向している。厚肉周壁部(13)と薄肉周壁部(14)との間には、両周壁部(13)(14)の内周面を繋ぐテーパ面(15)が形成されている。 Battery can (1)
As shown in FIGS. 1 and 2, the battery can (1) is configured by fixing a disc-shaped sealing body (2) to an opening of a cylindrical can body (11). An insulating member (12) is interposed between the sealing bodies (2). The can body (11) is formed by integrally molding a cylindrical peripheral wall (16) and a disk-shaped bottom wall (17) that closes one opening of the peripheral wall (16), and the peripheral wall (16) Consists of a thick peripheral wall portion (13) on the bottom wall (17) side and a thin peripheral wall portion (14) on the sealing body (2) side. The inner peripheral surface of the thick peripheral wall portion (13) protrudes inward from the inner peripheral surface of the thin inner peripheral wall (14) and is a cylindrical protrusion (49) formed by the negative electrode core of the winding electrode body (4). ) With a slight gap between them. A tapered surface (15) that connects the inner peripheral surfaces of the peripheral wall portions (13) and (14) is formed between the thick peripheral wall portion (13) and the thin peripheral wall portion (14).

封口体(２)は、中央孔(21a)が開設された蓋(21)と、該中央孔(21a)を覆う円筒状のキャップ(22)とを具え、蓋(21)の裏面には、前記中央孔(21a)と対向する位置に弁体(24)を具えた金属薄膜(25)が配備され、キャップ(22)の外周面には複数のガス排出孔(23)が開設されている。 The sealing body (2) includes a lid (21) having a central hole (21a) and a cylindrical cap (22) covering the central hole (21a). A metal thin film (25) having a valve body (24) is provided at a position facing the central hole (21a), and a plurality of gas discharge holes (23) are opened on the outer peripheral surface of the cap (22). .

次に、上記円筒型リチウムイオン二次電池の製造方法について説明する。
正極の作製
正極活物質としての平均粒径５μｍを有するリチウム複合酸化物(ＬｉＣｏＯ_２)の粉末と導電剤としての人造黒鉛とを９：１の重量比で混合し、正極合剤を得る。次に、結着剤であるポリフッ化ビニデンをＮ−メチル−２−ピロリドン(ＮＭＰ)に溶解させて、ＮＭＰ溶液を調製する。そして、正極合剤とポリフッ化ビニデンの重量比が９５：５となる様に正極合剤とＮＭＰ溶液を混合して、スラリーを調整する。このスラリーを正極芯体となる厚さ２０μｍのアルミニウム箔の両面にドクターブレード法により塗布し、１５０℃で２時間の真空乾燥を施して、正極を得る。 Next, a method for manufacturing the cylindrical lithium ion secondary battery will be described.
Production of Positive Electrode A lithium composite oxide (LiCoO ₂ ) powder having an average particle diameter of 5 μm as a positive electrode active material and artificial graphite as a conductive agent are mixed at a weight ratio of 9: 1 to obtain a positive electrode mixture. Next, polyvinylidene fluoride as a binder is dissolved in N-methyl-2-pyrrolidone (NMP) to prepare an NMP solution. Then, the positive electrode mixture and the NMP solution are mixed so that the weight ratio of the positive electrode mixture and the polyvinylidene fluoride is 95: 5 to prepare a slurry. This slurry is applied to both surfaces of a 20 μm-thick aluminum foil serving as a positive electrode core by a doctor blade method and vacuum dried at 150 ° C. for 2 hours to obtain a positive electrode.

負極の作製
炭素塊(ｄ００２＝３．３５６Å；Ｌｃ＞１０００)に空気流を噴射して粉砕し、炭素粉末を作製する。次に、結着剤であるポリフッ化ビニデンをＮＭＰに溶解させてＮＭＰ溶液を調製し、炭素粉末とポリフッ化ビニデンの重量比が８５：１５となる様に混練してスラリーを調製する。このスラリーを負極芯体となる厚さ２０μｍの銅箔の両面にドクターブレード法により塗布し、１５０℃で２時間の真空乾燥を施して、負極を得る。 Production of negative electrode A carbon mass (d002 = 3.356３; Lc> 1000) is jetted and pulverized to produce carbon powder. Next, polyvinylidene fluoride as a binder is dissolved in NMP to prepare an NMP solution, and a slurry is prepared by kneading so that the weight ratio of carbon powder to polyvinylidene fluoride is 85:15. This slurry is applied to both sides of a 20 μm thick copper foil serving as a negative electrode core by a doctor blade method and vacuum dried at 150 ° C. for 2 hours to obtain a negative electrode.

電解液の調製
エチレンカーボネートとジエチルカーボネートを１：１の体積比で混合した溶媒に、ＬｉＰＦ_６を１ｍｏｌ／ｌの割合で溶解し、電解液を調製する。 Preparation of Electrolytic Solution LiPF ₆ is dissolved at a ratio of 1 mol / l in a solvent in which ethylene carbonate and diethyl carbonate are mixed at a volume ratio of 1: 1 to prepare an electrolytic solution.

巻き取り電極体の作製
直径１０ｍｍの巻芯に、セパレータとなるイオン透過性のポリプロピレン製微多孔膜を数回巻いた後、セパレータが正極と負極の間に介在する様に、セパレータ、正極、セパレータ及び負極の４枚を重ね合わせてこれらを渦巻状に巻回し、最後に巻き芯を抜き取って巻き取り電極体を作製する。 Preparation of winding electrode body After winding an ion-permeable polypropylene microporous membrane serving as a separator several times around a core having a diameter of 10 mm, the separator, the positive electrode, and the separator so that the separator is interposed between the positive electrode and the negative electrode And four sheets of negative electrodes are piled up, these are wound in a spiral shape, and finally the winding core is removed to produce a wound electrode body.

組立工程
先ず、図１及び図２に示す缶本体(11)、封口板(２)、図３に示す巻き取り電極体(４)、正極側の集電板(３)及び負極側の集電板(30)をそれぞれ作製する。ここで、缶本体(11)は、ニッケル鍍金を施した鉄製であり、プレス加工によって周壁(16)と底壁(17)とを一体成型して形成され、周壁(16)の薄肉周壁部(14)の厚さは従来の周壁と同一の０.５ｍｍであり、厚肉周壁部(13)の厚さは０.８ｍｍであり、底壁(17)の厚さは０.５ｍｍである。 Assembling process First, the can body (11), the sealing plate (2) shown in FIGS. 1 and 2, the winding electrode body (4) shown in FIG. 3, the current collector plate (3) on the positive electrode side, and the current collector on the negative electrode side. Each plate (30) is produced. Here, the can body (11) is made of iron plated with nickel, and is formed by integrally molding the peripheral wall (16) and the bottom wall (17) by press working, and the thin peripheral wall portion of the peripheral wall (16) ( The thickness of 14) is 0.5 mm, the same as that of the conventional peripheral wall, the thickness of the thick peripheral wall portion (13) is 0.8 mm, and the thickness of the bottom wall (17) is 0.5 mm.

次に、巻き取り電極体(４)の両端部に形成されている芯体端縁(48a)(48b)に集電板(３)(30)を押し付ける。これによって、両集電板(３)(30)の円弧状凸部(32)(32)は、巻き取り電極体(４)の芯体端縁(48a)(48b)に食い込み、芯体端縁(48a)(48b)と圧着する。又、両集電板(３)(30)の切り起し片(33)(33)も同様に、巻き取り電極体(４)の芯体端縁(48a)(48b)に深く食い込み、芯体端縁(48a)(48b)と圧着する。
この状態で、両集電板(３)(30)の円弧状凸部(32)(32)の内周面に向けてレーザビームを照射し、レーザ溶接を施す。この結果、集電板(３)(30)の円弧状凸部(32)(32)と巻き取り電極体(４)の芯体端縁(48a)(48b)とが、大きな接触面積で互いに接合されると共に、切り起し片(33)(33)と芯体端縁(48a)(48b)の間の圧着状態が維持されることになる。 Next, the current collector plates (3) and (30) are pressed against the core body edges (48a) and (48b) formed at both ends of the winding electrode body (4). As a result, the arc-shaped protrusions (32) and (32) of the current collector plates (3) and (30) bite into the core body edges (48a) and (48b) of the winding electrode body (4), and the core body ends. Crimp with edges (48a) and (48b). Similarly, the cut and raised pieces (33) and (33) of the current collector plates (3) and (30) deeply bite into the edges (48a) and (48b) of the core body of the winding electrode body (4). Crimp with body edge (48a) (48b).
In this state, laser welding is performed by irradiating laser beams toward the inner peripheral surfaces of the arc-shaped convex portions (32) and (32) of the current collector plates (3) and (30). As a result, the arcuate protrusions (32), (32) of the current collector plates (3), (30) and the core edges (48a), (48b) of the winding electrode body (4) are in contact with each other with a large contact area. While being joined, the pressure-bonded state between the cut and raised pieces (33) (33) and the core body edges (48a) (48b) is maintained.

その後、集電板(３)(30)を設置した巻き取り電極体(４)を缶本体(11)の内部に収容する。このとき、周壁(16)のテーパ面(15)の案内によって巻き取り電極体(４)を缶本体(11)の奥方に挿入することが出来るので、負極側の集電板(30)を底壁(17)に設置する作業は容易となる。然も、前記テーパ面(15)に案内によって、負極側の集電板(30)の本体(31)の中央部は、正確に底壁(17)の中心位置に設置されることになる。 Then, the winding electrode body (4) on which the current collector plates (3) and (30) are installed is accommodated in the can body (11). At this time, the winding electrode body (4) can be inserted into the can main body (11) by guiding the taper surface (15) of the peripheral wall (16), so that the current collector plate (30) on the negative electrode side can be The installation work on the wall (17) becomes easy. However, the central portion of the main body (31) of the current collector plate (30) on the negative electrode side is accurately placed at the center position of the bottom wall (17) by guiding to the tapered surface (15).

この状態で、負極側の集電板(30)の本体(31)の中央部を、缶本体(11)の底壁(17)にスポット溶接する。
次に、正極側の集電板(３)のリード(35)の先端を封口体(２)の金属薄膜(25)にレーザ溶接する。
その後、缶本体(11)内に電解液を注入し、該缶本体(11)の開口部に絶縁性部材(12)を介して封口体(２)をかしめ固定し、外径が３６ｍｍ、高さが９０ｍｍの本発明の円筒型リチウムイオン二次電池を完成する。 In this state, the center part of the main body (31) of the current collector plate (30) on the negative electrode side is spot welded to the bottom wall (17) of the can main body (11).
Next, the tip of the lead (35) of the current collector plate (3) on the positive electrode side is laser welded to the metal thin film (25) of the sealing body (2).
Thereafter, an electrolytic solution is injected into the can body (11), and the sealing body (2) is caulked and fixed to the opening of the can body (11) through the insulating member (12). A cylindrical lithium ion secondary battery of the present invention having a length of 90 mm is completed.

電池ユニット
図６に示す如く、ジョイントキャップ(６)を用いて上記本発明の複数本の円筒型リチウムイオン二次電池を直列に接続し、一体の電池ユニットを構成する。 Battery Unit As shown in FIG. 6, a plurality of cylindrical lithium ion secondary batteries of the present invention are connected in series using a joint cap (6) to constitute an integral battery unit.

ジョイントキャップ(６)は、図６に示す如く、一方の電池(1b)の負極端子部(10)を構成する缶本体(11)の底壁(17)を包囲すべき円筒状の第１接続部(61)と、他方の電池(1a)の正極端子部(20)を構成するキャップ(22)を包囲すべき円筒状の第２接続部(62)とから構成されている。 As shown in FIG. 6, the joint cap (6) is a cylindrical first connection that should surround the bottom wall (17) of the can body (11) that constitutes the negative terminal (10) of one battery (1b). And a cylindrical second connection portion (62) that should surround the cap (22) constituting the positive electrode terminal portion (20) of the other battery (1a).

第１接続部(61)は、前記一方の電池(1b)の缶本体(11)の底壁(17)と対向する円板状の第１平板部(63)と、該第１平板部(63)の外周縁に突設されて缶本体(11)の周壁(16)を包囲するスカート部(64)とから構成されている。第１平板部(63)には中央孔が開設され、スカート部(64)の内周面には、周壁(16)の厚肉周壁部(13)に向かって突出する複数の第１プロジェクション(65)が形成されている。 The first connecting portion (61) includes a disk-shaped first flat plate portion (63) facing the bottom wall (17) of the can body (11) of the one battery (1b), and the first flat plate portion ( 63) and a skirt portion (64) projecting from the outer peripheral edge of the can body (11) and surrounding the peripheral wall (16). A central hole is formed in the first flat plate portion (63), and a plurality of first projections projecting toward the thick peripheral wall portion (13) of the peripheral wall (16) are formed on the inner peripheral surface of the skirt portion (64). 65) is formed.

第２接続部(62)は、前記他方の電池(1a)の封口体(２)の蓋(21)と対向する円板状の第２平板部(68)と、該第２平板部(68)の外周縁に突設されて封口体(２)のキャップ(22)の外周面を包囲する円筒部(69)とから構成され、円筒部(69)の先端は、第１接続部(61)の第１平板部(63)の内周縁に連結されている。又、第２平板部(68)には中央孔が開設されると共に、封口体(２)の蓋(21)に向かって突出する複数の第２プロジェクション(66)が形成され、円筒部(69)には、複数のガス排出孔(67)が開設されている。 The second connecting portion (62) includes a disc-shaped second flat plate portion (68) facing the lid (21) of the sealing body (2) of the other battery (1a), and the second flat plate portion (68 ) And a cylindrical portion (69) surrounding the outer peripheral surface of the cap (22) of the sealing body (2), and the tip of the cylindrical portion (69) is connected to the first connecting portion (61). ) Of the first flat plate portion (63). In addition, a central hole is formed in the second flat plate portion (68), and a plurality of second projections (66) protruding toward the lid (21) of the sealing body (2) are formed, and the cylindrical portion (69 ) Is provided with a plurality of gas discharge holes (67).

２本の電池(1a)(1b)を直列に接続する場合には、先ず、前記他方の電池(1a)の封口体(２)のキャップ(22)をジョイントキャップ(６)の第２接続部(62)の第２平板部(68)の中央孔に挿入して、該第２平板部(68)を封口体(２)の蓋(21)の表面と対向させ、この状態で第２プロジェクション(66)を蓋(21)の表面にレーザ溶接若しくはスポット溶接する。 When two batteries (1a) (1b) are connected in series, first, the cap (22) of the sealing body (2) of the other battery (1a) is connected to the second connecting portion of the joint cap (6). The second flat plate portion (68) is inserted into the central hole of the second flat plate portion (68) so that the second flat plate portion (68) faces the surface of the lid (21) of the sealing body (2). (66) is laser welded or spot welded to the surface of the lid (21).

次に、ジョイントキャップ(６)の第１接続部(61)に前記一方の電池(1b)を設置し、スカート部(64)を周壁(16)の厚肉周壁部(13)に対向させ、この状態で第１プロジェクション(65)を厚肉周壁部(13)にレーザ溶接する。このとき、第１プロジェクション(65)に照射すべきレーザビームの電力値を従来の３３０Ｗから４００Ｗに増大させて上述のレーザ溶接を行なう。これによって、第１プロジェクション(65)と厚肉周壁部(13)の接触面には、従来よりも大きな溶接熱が発生することになるが、厚肉周壁部(13)は、厚さ０.５ｍｍの薄
肉周壁部のみによって構成される従来の周壁の厚さよりも０.３ｍｍ大きく、従来の周壁
と比べて単位面積当り十分に大きな熱容量を有しているので、前記溶接熱によって厚肉周壁部(13)が損傷を受けることはない。
この様にして、２本以上の電池を直列に接続することによって、所望の電力や電圧を得ることの出来る電池ユニットが構成される。 Next, the one battery (1b) is installed in the first connection part (61) of the joint cap (6), the skirt part (64) is opposed to the thick peripheral wall part (13) of the peripheral wall (16), and In this state, the first projection (65) is laser welded to the thick peripheral wall (13). At this time, the above-mentioned laser welding is performed by increasing the power value of the laser beam to be irradiated to the first projection (65) from the conventional 330W to 400W. As a result, larger welding heat is generated on the contact surface between the first projection (65) and the thick peripheral wall portion (13) than in the prior art, but the thick peripheral wall portion (13) has a thickness of 0. Since the thickness of the conventional peripheral wall constituted by only the thin peripheral wall portion of 5 mm is 0.3 mm larger than the conventional peripheral wall and has a sufficiently large heat capacity per unit area, the thick peripheral wall portion is generated by the welding heat. (13) will not be damaged.
Thus, the battery unit which can obtain desired electric power and voltage is comprised by connecting two or more batteries in series.

上記本発明の電池ユニットにおいては、従来よりも大きな溶接熱を発生させてジョイントキャップ(６)の第１プロジェクション(65)を缶本体(11)の周壁(16)の厚肉周壁部(13)に溶接接合することにより、第１プロジェクション(65)の溶け込み量が増大するので、第１プロジェクション(65)と厚肉周壁部(13)との溶接部の面積が増大する。この結果、該溶接部を通過する電流経路の断面積が増大して該電流経路の電気抵抗は従来よりも小さなものとなり、これによってユニット全体の出力が増大する。 In the battery unit of the present invention, welding heat larger than the conventional one is generated, and the first projection (65) of the joint cap (6) is attached to the thick peripheral wall portion (13) of the peripheral wall (16) of the can body (11). By welding and joining, the amount of penetration of the first projection (65) increases, so that the area of the welded portion between the first projection (65) and the thick peripheral wall portion (13) increases. As a result, the cross-sectional area of the current path passing through the welded portion increases, and the electric resistance of the current path becomes smaller than before, thereby increasing the output of the entire unit.

又、本発明に係る電池ユニットの円筒型リチウムイオン二次電池においては、図７に示す如く、缶本体(11)の底壁を、厚肉周壁部(13)と同一の０.８ｍｍの厚さを有する厚肉底壁(17a)によって形成することも可能である。
In the cylindrical lithium ion secondary battery of the battery unit according to the present invention, as shown in FIG. 7, the bottom wall of the can body (11) has a thickness of 0.8 mm, which is the same as the thick peripheral wall portion (13). It can also be formed by a thick bottom wall (17a) having a thickness.

従って、該リチウムイオン二次電池によれば、前記溶接部に大きな溶接熱を発生させて負極側の集電板(30)の本体(31)の溶け込み量を増大させることが出来、これによって厚肉底壁(17a)と前記本体(31)の溶接部の面積を増大させることが出来る。この結果、該溶接部を通過する電流経路の断面積が増大することになり、該電流経路の電気抵抗が低減して電池出力が増大する。 Therefore, according to the lithium ion secondary battery, it is possible to increase the amount of penetration of the main body (31) of the current collector plate (30) on the negative electrode side by generating a large welding heat in the welded portion. The area of the welded portion between the bottom wall (17a) and the main body (31) can be increased. As a result, the cross-sectional area of the current path that passes through the weld is increased, the electric resistance of the current path is reduced, and the battery output is increased.

又、図７に示す円筒型リチウムイオン二次電池及び上述のジョイントキャップ(６)を用いることにより、図８に示す電池ユニットを構成することが出来る。
該電池ユニットによれば、従来よりも大きな溶接熱を発生させて第１プロジェクション(65)を周壁(16)の厚肉周壁部(13)に溶接することが出来、これによって、電池出力が従来よりも大きな円筒型リチウムイオン二次電池とジョイントキャップ(６)の溶接接合部の面積を増大させることが出来、ユニット全体の出力を大幅に増大させることが出来る。 Further, by using the cylindrical lithium ion secondary battery shown in FIG. 7 and the joint cap (6) described above, the battery unit shown in FIG. 8 can be configured.
According to the battery unit, it is possible to weld the first projection (65) to the thick peripheral wall portion (13) of the peripheral wall (16) by generating a larger welding heat than before, and thereby the battery output is conventionally increased. The area of the welded joint between the larger cylindrical lithium ion secondary battery and the joint cap (6) can be increased, and the output of the entire unit can be greatly increased.

本発明の電池ユニット及び比較例の電池ユニットを作製し、本発明の効果を確認した。
上述の製造方法によって図１に示す本発明の電池ユニットに用いる円筒型リチウムイオン二次電池(第１電池)を２本作製する。ここで、第１電池の電池Ａ及び電池Ｂに配備された負極側の集電板と缶本体の底壁との溶接接合部には、０.９ｋＷの電力を１５ｍｓの時間印加し、連続で２.０ｋＷの電力を２０ｍｓの時間印加する条件でスポット溶接を施す。
又、缶本体の底壁の厚さが０.８ｍｍであることを除いて第１電池と同一構成の図７に示す本発明の他の電池ユニットに用いる円筒型リチウムイオン二次電池(第２電池)を２本作製する。但し、第２電池の電池Ｃ及び電池Ｄに配備された負極側の集電板と缶本体の底壁との溶接接合部には、０.９ｋＷの電力を１５ｍｓの時間印加し、連続で３.０ｋＷの電力を２０ｍｓの時間印加する条件でスポット溶接を施す。
又、缶本体(１)の厚さが全ての領域で０.５ｍｍであることを除いて第１電池と同一構成の図９に示す比較例の電池ユニットに用いる円筒型リチウムイオン二次電池(第３電池)を２本作製する。但し、第３電池の電池Ｅ及び電池Ｆに配備された負極側の集電板と缶本体の底壁との溶接接合部には、０.９ｋＷの電力を１５ｍｓの時間印加し、連続で２.０ｋＷの電力を２０ｍｓの時間印加する条件でスポット溶接を施す。
The battery unit of the present invention and the battery unit of the comparative example were produced, and the effects of the present invention were confirmed.
Two cylindrical lithium ion secondary batteries (first batteries) used in the battery unit of the present invention shown in FIG. 1 are manufactured by the above-described manufacturing method. Here, 0.9 kW of electric power was applied for 15 ms to the welded joint between the negative electrode current collector plate and the bottom wall of the can body provided in the batteries A and B of the first battery. Spot welding is performed under the condition that a power of 2.0 kW is applied for 20 ms.
Also, a cylindrical lithium ion secondary battery (second battery) used in another battery unit of the present invention shown in FIG. 7 having the same configuration as that of the first battery except that the thickness of the bottom wall of the can body is 0.8 mm. Two batteries are produced. However, 0.9 kW of electric power was applied for 15 ms to the welded joint between the negative electrode current collector plate and the bottom wall of the can body provided in the batteries C and D of the second battery, and continuously 3 Spot welding is performed under the condition that a power of 0.0 kW is applied for 20 ms.
Also, a cylindrical lithium ion secondary battery used in the battery unit of the comparative example shown in FIG. 9 having the same configuration as the first battery except that the thickness of the can body (1) is 0.5 mm in all regions ( Two third batteries are produced. However, 0.9 kW of electric power was applied for 15 ms to the welded joint between the negative electrode current collector plate and the bottom wall of the can body provided in the battery E and battery F of the third battery, and continuously 2 Spot welding is performed under the condition that a power of 0.0 kW is applied for 20 ms.

その後、各々２本の第１電池、第２電池及び第３電池をそれぞれジョイントキャップを介して直列に接続して３種類の電池ユニットを形成する。このとき、各ジョイントキャップの第２接続部の第２プロジェクションを電池Ａ、電池Ｃ及び電池Ｅの封口体の蓋にスポット溶接し、第１接続部の第１プロジェクションは、第１電池及び第２電池にあっては電池Ｂ及び電池Ｄの厚肉周壁部に、第３電池にあっては電池Ｆの周壁にそれぞれレーザ溶接する。ここで、電池Ｂ及び電池Ｄの厚肉周壁部に溶接される第１プロジェクションは、電力値が４００Ｗのレーザビームによって照射され、電池Ｆの周壁に溶接される第１プロジェクションは、電力値が３３０Ｗのレーザビームによって照射される。
Thereafter, each of the two first batteries, the second battery, and the third battery is connected in series via a joint cap to form three types of battery units. At this time, the second projection of the second connection portion of each joint cap is spot welded to the lid of the sealing body of the battery A, the battery C, and the battery E, and the first projection of the first connection portion is the first battery and the second Laser welding is performed on the thick wall portions of the batteries B and D for the battery, and laser welding is performed on the peripheral wall of the battery F for the third battery. Here, the first projection welded to the thick peripheral walls of the battery B and the battery D is irradiated with a laser beam having a power value of 400 W, and the first projection welded to the peripheral wall of the battery F has a power value of 330 W. The laser beam is irradiated.

そして、各電池ユニットの２本の電池間の電気抵抗(１ｋＨｚ交流インピーダンス)を測定したところ、第１電池によって構成される本発明の電池ユニットの電気抵抗が２.９ｍΩ、第２電池によって構成される本発明の電池ユニットの電気抵抗が２.７ｍΩであったのに対し、第３電池によって構成される比較例の電池ユニットの電気抵抗は３.２ｍΩであった。
このことから、第１プロジェクションを厚肉周壁部に大きな溶接熱で溶接することにより、第１プロジェクションと厚肉周壁部の溶接部の電気抵抗が確実に低減されることが確認された。又、第１電池を用いた本発明の電池ユニットよりも第２電池を用いた本発明の電池ユニットの電気抵抗が小さいことから、電池缶の底壁に負極側の集電板を大きな溶接熱で溶接することにより、集電板と底壁の溶接部の電気抵抗が確実に低減されることが確認された。
And when the electrical resistance (1 kHz alternating current impedance) between two batteries of each battery unit was measured, the electrical resistance of the battery unit of the present invention constituted by the first battery was 2.9 mΩ, and constituted by the second battery. The electric resistance of the battery unit of the present invention was 2.7 mΩ, whereas the electric resistance of the battery unit of the comparative example constituted by the third battery was 3.2 mΩ.
From this, it was confirmed that the electrical resistance of the welded portion between the first projection and the thick peripheral wall portion is reliably reduced by welding the first projection to the thick peripheral wall portion with a large welding heat. In addition, since the electric resistance of the battery unit of the present invention using the second battery is smaller than that of the battery unit of the present invention using the first battery , the negative collector plate is attached to the bottom wall of the battery can with a large welding heat. It was confirmed that the electrical resistance of the welded portion between the current collector plate and the bottom wall is surely reduced by welding with.

又、第１電池の電池Ｂとジョイントキャップの第１プロジェクションとの溶接部と、第３電池の電池Ｆとジョイントキャップの第１プロジェクションとの溶接部とを、それぞれ観察した。
この結果、電池Ｂの厚肉周壁部の溶接部にはいかなる溶接痕も確認することが出来なかったのに対し、電池Ｆの周壁の溶接部には溶接痕が僅かに確認された。このことから、厚肉周壁部の単位面積当りの熱容量は十分に大きく、第１プロジェクションの溶融量を増大させるための大きな溶接熱に十分に耐え得ることが確認された。
Further, the welded portion between the battery B of the first battery and the first projection of the joint cap, and the welded portion of the battery F of the third battery and the first projection of the joint cap were observed.
As a result, no welding marks could be confirmed in the welded portion of the thick peripheral wall portion of the battery B, whereas slight welding marks were confirmed in the welded portion of the peripheral wall of the battery F. From this, it was confirmed that the heat capacity per unit area of the thick-walled peripheral wall portion is sufficiently large and can sufficiently withstand the large welding heat for increasing the melting amount of the first projection.

本発明の電池ユニットに係る円筒型リチウムイオン二次電池を示す断面図である。It is sectional drawing which shows the cylindrical lithium ion secondary battery which concerns on the battery unit of this invention . 該円筒型リチウムイオン二次電池の構成を示す一部破断斜視図である。It is a partially broken perspective view which shows the structure of this cylindrical lithium ion secondary battery. 該円筒型リチウムイオン二次電池の集電板と一部を展開した巻き取り電極体の斜視図である。It is a perspective view of the winding electrode body which unfolded the current collecting plate and part of this cylindrical lithium ion secondary battery. 正極側の集電板を示す平面図である。It is a top view which shows the current collecting plate by the side of a positive electrode. 図４のＡ−Ａ線に沿う断面図である。It is sectional drawing which follows the AA line of FIG. 図４のＢ−Ｂ線に沿う断面図である。It is sectional drawing which follows the BB line of FIG. 本発明の電池ユニットに係る２本の円筒型リチウムイオン二次電池をジョイントキャップによって直列に接続した状態を拡大して示す断面図である。It is sectional drawing which expands and shows the state which connected the two cylindrical lithium ion secondary batteries which concern on the battery unit of this invention in series with the joint cap. 本発明の電池ユニットに係る他の円筒型リチウムイオン二次電池を示す断面図である。It is sectional drawing which shows the other cylindrical lithium ion secondary battery which concerns on the battery unit of this invention . 本発明の電池ユニットに係る他の２本の円筒型リチウムイオン二次電池をジョイントキャップによって直列に接続した状態を拡大して示す断面図である。It is sectional drawing which expands and shows the state which connected the other two cylindrical lithium ion secondary batteries which concern on the battery unit of this invention in series with the joint cap. 比較例の電池ユニットに係る円筒型リチウムイオン二次電池を示す断面図である。It is sectional drawing which shows the cylindrical lithium ion secondary battery which concerns on the battery unit of a comparative example . 比較例の電池ユニットに係る２本の円筒型リチウムイオン二次電池をジョイントキャップによって直列に接続した状態を拡大して示す断面図である。It is sectional drawing which expands and shows the state which connected the two cylindrical lithium ion secondary batteries which concern on the battery unit of a comparative example in series with the joint cap.

Explanation of symbols

(１) 電池缶
(1a) 電池
(1b) 電池
(10) 負極端子部
(12) 絶縁部材
(13) 厚肉周壁部
(14) 薄肉周壁部
(15) テーパ面
(16) 周壁
(17) 底壁
(17a) 厚肉底壁
(２) 封口体
(20) 正極端子部
(21) 蓋
(22) キャップ
(３) 集電板
(30) 集電板
(４) 巻き取り電極体
(６) ジョイントキャップ
(61) 第１接続部
(62) 第２接続部
(64) スカート部
(65) 第１プロジェクション (1) Battery can
(1a) Battery
(1b) Battery
(10) Negative terminal
(12) Insulation material
(13) Thick wall
(14) Thin peripheral wall
(15) Tapered surface
(16) Perimeter wall
(17) Bottom wall
(17a) Thick bottom wall
(2) Sealing body
(20) Positive terminal
(21) Lid
(22) Cap
(3) Current collector
(30) Current collector
(4) Winding electrode body
(6) Joint cap
(61) First connection
(62) Second connection
(64) Skirt
(65) 1st projection

Claims

The battery body is constructed by connecting a plurality of batteries having a pair of electrode terminal portions provided at both ends of the battery body in series, and a joint cap (6) between two consecutive batteries (1a) (1b). In the battery unit in which
The battery includes a battery can (1) having a sealing body (2) attached to an opening of a cylindrical can body (11), and a secondary battery element is accommodated in the battery can (1). The power generated by the secondary battery element can be taken out from the pair of positive and negative electrode terminal portions (10), (20), and the can body (11) has a cylindrical peripheral wall (16) and A bottom wall that closes one opening of the peripheral wall (16) is integrally formed, and one electrode terminal portion (10) is constituted by the bottom wall, and the other is formed by the sealing body (2). Electrode terminal portion (20), and the peripheral wall (16) is composed of a thick peripheral wall portion (13) on the bottom wall side and a thin peripheral wall portion (14) on the sealing body (2) side,
The joint cap (6) includes a first connecting part (61) to be in contact with the bottom wall of the can body (11) of the first battery (1b) and a sealing body (2) of the second battery (1a). And a flat plate portion (63) facing the bottom wall of the can body (11) of the first battery (1b). And a cylindrical skirt portion (64) protruding from the outer peripheral edge of the flat plate portion (63) and surrounding the peripheral wall (16) of the can body (11) of the first battery (1b), The skirt portion (64) is welded to the thick peripheral wall portion (13) of the peripheral wall (16) of the first battery (1b) .