JP6988335B2 - Welded part forming method - Google Patents

Welded part forming method Download PDF

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JP6988335B2
JP6988335B2 JP2017190088A JP2017190088A JP6988335B2 JP 6988335 B2 JP6988335 B2 JP 6988335B2 JP 2017190088 A JP2017190088 A JP 2017190088A JP 2017190088 A JP2017190088 A JP 2017190088A JP 6988335 B2 JP6988335 B2 JP 6988335B2
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tab
group
uncoated portion
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JP2019067570A (en
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康寿 松浦
亮太 磯村
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Toyota Industries Corp
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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
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/10—Energy storage using batteries

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Description

本発明は、導電部材と未塗工部群とをレーザ溶接した溶接部の形成方法に関する。 The present invention relates to a method for forming a welded portion by laser welding a conductive member and an uncoated portion group.

従来から、ＥＶ（Electric Vehicle）やＰＨＶ（Plug in Hybrid Vehicle）などの車両には、電動機などへの供給電力を蓄える蓄電装置としてリチウムイオン二次電池などが搭載されている。二次電池は、複数のシート状の正極電極と負極電極とが絶縁された状態で交互に積層された電極組立体と、該電極組立体を収容するケースとを備える。 Conventionally, vehicles such as EVs (Electric Vehicles) and PHVs (Plugs in Hybrid Vehicles) are equipped with lithium ion secondary batteries and the like as storage devices for storing power supplied to electric vehicles and the like. The secondary battery includes an electrode assembly in which a plurality of sheet-shaped positive electrode and negative electrode are alternately laminated in an insulated state, and a case for accommodating the electrode assembly.

正極電極及び負極電極は、金属箔と、金属箔の両面又は片面に存在する活物質層と、活物質層が存在せず、金属箔が露出する未塗工部とを有する。未塗工部は、例えば、金属箔の一辺から突出したタブである。電極組立体は、各極性のタブが積層された未塗工部群としてのタブ群を備える。二次電池からの電力の取り出しは、電極組立体と電気的に接続された電極端子を通して行われる。電極組立体と電極端子とは、タブ群と電極端子に導電部材を溶接することで電気的に接続されている。 The positive electrode and the negative electrode have a metal foil, an active material layer existing on both sides or one side of the metal foil, and an uncoated portion where the active material layer does not exist and the metal foil is exposed. The uncoated portion is, for example, a tab protruding from one side of the metal foil. The electrode assembly includes a tab group as an uncoated portion group in which tabs of each polarity are laminated. Power is drawn from the secondary battery through the electrode terminals that are electrically connected to the electrode assembly. The electrode assembly and the electrode terminals are electrically connected to each other by welding a conductive member to the tab group and the electrode terminals.

ところで、タブ群と導電部材との溶接において、タブ群を構成するタブの枚数が多くなるほど、全てのタブを一度に溶接する際のタブの積層方向における溶け込み深さが深くなるため、溶接に要するレーザ光のエネルギーが大きくなる。この場合、タブ群のうちレーザ光の照射位置に近いタブに破れが生じることがある。これに対し、例えば特許文献１では、保護板と導電部材とでタブ群を挟み込んでレーザ溶接することで、溶接時のタブの破れを抑制している。 By the way, in welding the tab group and the conductive member, the larger the number of tabs constituting the tab group, the deeper the penetration depth in the stacking direction of the tabs when all the tabs are welded at once, which is necessary for welding. The energy of the laser beam increases. In this case, the tabs in the tab group near the laser beam irradiation position may be torn. On the other hand, in Patent Document 1, for example, the tab group is sandwiched between the protective plate and the conductive member and laser welded to suppress the tearing of the tab during welding.

特開２０１６−００２５６６号公報Japanese Unexamined Patent Publication No. 2016-002566

しかしながら、保護板は、タブ群と導電部材を溶接する際に、タブ群に溶接されるため、タブ群と導電部材とを溶接する度に必要になる。また、保護板は、二次電池の部品点数の増加につながる。 However, since the protective plate is welded to the tab group when the tab group and the conductive member are welded, it is required every time the tab group and the conductive member are welded. In addition, the protective plate leads to an increase in the number of parts of the secondary battery.

本発明の目的は、保護板を用いなくても未塗工部の破れの発生を抑制できる溶接部の形成方法を提供することにある。 An object of the present invention is to provide a method of forming a welded portion even Ru can suppress the occurrence of breakage of the uncoated portions without using a protective plate.

上記問題点を解決するための溶接部の形成方法は、金属箔の少なくとも片面に活物質層を有するとともに、前記活物質層が存在せず、前記金属箔が露出する未塗工部とを有する正極及び負極の電極が絶縁された状態で積層され、かつ前記未塗工部が同じ極性同士で積層された未塗工部群を備える電極組立体と、前記未塗工部群と接合された導電部材と、を備える蓄電装置において、前記導電部材と前記未塗工部群とをレーザ溶接した溶接部の形成方法であって、前記未塗工部群の積層方向一端の未塗工部より外側に前記導電部材を配置し、筒状の治具本体と、前記治具本体を軸方向に貫通し、レーザ光を通過させる貫通孔と、前記治具本体の軸方向に連設され、かつ前記レーザ光の進行方向に対する直交方向に５０μｍより広く５ｍｍ以下の間隔を空けた状態で対向する部位を備える接触部と、を有した溶接用治具を、前記未塗工部群の積層方向他端の未塗工部に直接接触させ、前記積層方向他端の未塗工部に直接接触する前記接触部の端面の面積は、前記治具本体の端面の面積より小さくなっており、前記溶接用治具により前記未塗工部群を積層方向に１〜２ｋｇｆ／ｃｍ ２ の加圧力で加圧した状態で、前記溶接用治具の貫通孔を通過するレーザ光を前記進行方向に移動させながら前記積層方向他端の未塗工部に直接照射することを要旨とする。 A method for forming a welded portion for solving the above problems includes an active material layer on at least one surface of the metal foil, and an uncoated portion in which the active material layer does not exist and the metal foil is exposed. An electrode assembly having an uncoated portion group in which positive electrode and negative electrode electrodes are laminated in an insulated state and the uncoated portions are laminated with the same polarity is joined to the uncoated portion group. A method for forming a welded portion by laser welding the conductive member and the uncoated portion group in a power storage device including the conductive member, from the uncoated portion at one end in the stacking direction of the uncoated portion group. The conductive member is arranged on the outside, and a tubular jig body, a through hole that penetrates the jig body in the axial direction and allows laser light to pass through, and a series of holes in the axial direction of the jig body are provided. A welding jig having a contact portion having a portion facing each other at a distance of 5 mm or less, which is wider than 50 μm in a direction orthogonal to the traveling direction of the laser beam, is provided in the stacking direction of the uncoated portion group and the like. in direct contact with the uncoated portion of the end area of the end face of the contact portion in direct contact with the uncoated portion of the stacking direction end is smaller than the area of the end face of the jig body, the welding in a state in which the pressurized the uncoated portion group under a pressure of 1~2kgf / cm 2 in the stacking direction by use jig to move the laser beam passing through the through hole of the welding jig to the traveling direction However, the gist is to directly irradiate the uncoated portion at the other end in the stacking direction.

これによれば、溶接用治具の接触部を未塗工部群に接触させて加圧することで、未塗工部群において、接触部によって５０μｍより広く５ｍｍ以下の範囲で挟まれた箇所を突っ張った状態にし、積層方向に隣り合う未塗工部同士を密着した状態にできる。このため、レーザ溶接して溶接部を形成する際、未塗工部群の積層方向全体に溶融が進みやすくなり、レーザ光の照射位置に近い未塗工部（積層方向他端側の未塗工部）にエネルギーが集中することが抑制される。よって、保護板のない構成で未塗工部の破れの発生を抑制できる。 According to this, by contacting the contact portion of the welding jig with the uncoated portion group and pressurizing it, in the uncoated portion group, the portion sandwiched by the contact portion in a range of 5 mm or less, which is wider than 50 μm. The uncoated parts that are adjacent to each other in the stacking direction can be brought into close contact with each other in a stretched state. For this reason, when laser welding is performed to form a welded portion, melting tends to proceed in the entire stacking direction of the uncoated portion group, and the uncoated portion near the irradiation position of the laser beam (unpainted on the other end side in the stacking direction). Concentration of energy on the engineering department) is suppressed. Therefore, it is possible to suppress the occurrence of tearing of the uncoated portion with a configuration without a protective plate.

また、前記接触部は筒状であるため、レーザ光の照射によって発生したスパッタが、接触部によって溶接用治具の外へ飛散することを抑制できる。 The front SL contact portion for a cylindrical, sputtering generated by the irradiation of the laser beam can be prevented from scattering to the outside of the welding jig by the contact portion.

また、前記溶接用治具によって前記未塗工部群を加圧する際は１〜２ｋｇｆ／ｃｍ２の加圧力で加圧するため、未塗工部群の積層方向一端の未塗工部より外側に配置された導電部材が、加圧力によって撓むことを抑制できるとともに、加圧によって、未塗工部を突っ張った状態にできる。 Further, when pressurizing the uncoated portion group by the previous SL welding jig is to pressurize by pressure of 1~2kgf / cm 2, outside the uncoated portion of the stacking direction end of the uncoated portion group The conductive member arranged in the above can be suppressed from bending due to the pressing force, and the uncoated portion can be in a stretched state by the pressing force.

本発明によれば、保護板を用いなくても未塗工部の破れの発生を抑制できる。 According to the present invention, it is possible to suppress the occurrence of tearing of the uncoated portion without using a protective plate.

実施形態の二次電池を示す分解斜視図。The exploded perspective view which shows the secondary battery of an embodiment. 実施形態の二次電池を示す部分側断面図。A partial side sectional view showing a secondary battery of an embodiment. （ａ）はタブ群を延ばした状態での溶接部を示す断面図、（ｂ）はタブ群を延ばした状態での溶接部を示す平面図、（ｃ）はレーザ光の動きを示す図。(A) is a cross-sectional view showing a welded portion in a state where the tab group is extended, (b) is a plan view showing a welded portion in a state where the tab group is extended, and (c) is a diagram showing the movement of a laser beam. （ａ）は溶接用治具を示す斜視図、（ｂ）は溶接用治具を示す断面図。(A) is a perspective view showing a welding jig, and (b) is a sectional view showing a welding jig. 溶接用治具をエアシリンダで押圧した状態を示す斜視図。The perspective view which shows the state which pressed the welding jig with an air cylinder. レーザ溶接を行う状態を示す図。The figure which shows the state which performs laser welding. 溶接用治具と溶接部を示す平面図。A plan view showing a welding jig and a welded portion.

以下、溶接用治具を具体化した一実施形態を図１〜図７にしたがって説明する。
図１又は図２に示すように、蓄電装置としての二次電池１０は、ケース１１を備える。二次電池１０は、ケース１１に収容された電極組立体１２及び電解液（図示せず）を備える。ケース１１は、直方体状のケース本体１３と、ケース本体１３の開口部１３ａを閉塞する矩形平板状の蓋１４とを有する。ケース１１を構成するケース本体１３と蓋１４は、何れも金属製（例えば、ステンレスやアルミニウム）である。また、本実施形態の二次電池１０は、その外観が角型をなす角型電池である。また、本実施形態の二次電池１０は、リチウムイオン電池である。 Hereinafter, an embodiment in which the welding jig is embodied will be described with reference to FIGS. 1 to 7.
As shown in FIG. 1 or 2, the secondary battery 10 as a power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 12 housed in a case 11 and an electrolytic solution (not shown). The case 11 has a rectangular parallelepiped case body 13 and a rectangular flat plate-shaped lid 14 that closes the opening 13a of the case body 13. The case body 13 and the lid 14 constituting the case 11 are both made of metal (for example, stainless steel or aluminum). Further, the secondary battery 10 of the present embodiment is a square battery having a square appearance. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

二次電池１０は、電極組立体１２から電気を取り出すための一対の電極端子１５を備える。一対の電極端子１５のうち、一方の電極端子１５は正極の電極端子であり、他方の電極端子１５は負極の電極端子である。各電極端子１５は、蓋１４の孔１４ａを貫通してケース１１外に突出する。各電極端子１５には、蓋１４と絶縁するためのリング状の絶縁リング１６がそれぞれ取り付けられている。各電極端子１５は、ケース１１内に矩形板状の導電部材１７を有する。各電極端子１５は導電部材１７と接合され、導電部材１７を介して電極組立体１２と電極端子１５は電気的に接続されている。 The secondary battery 10 includes a pair of electrode terminals 15 for extracting electricity from the electrode assembly 12. Of the pair of electrode terminals 15, one electrode terminal 15 is a positive electrode terminal, and the other electrode terminal 15 is a negative electrode terminal. Each electrode terminal 15 penetrates the hole 14a of the lid 14 and projects to the outside of the case 11. A ring-shaped insulating ring 16 for insulating the lid 14 is attached to each electrode terminal 15. Each electrode terminal 15 has a rectangular plate-shaped conductive member 17 in the case 11. Each electrode terminal 15 is joined to a conductive member 17, and the electrode assembly 12 and the electrode terminal 15 are electrically connected via the conductive member 17.

電極組立体１２は、複数枚のシート状の正極の電極としての正極電極２１と、複数枚のシート状の負極の電極としての負極電極２２とを備える。電極組立体１２は、正極電極２１と負極電極２２との間にセパレータ２３を介在させて絶縁させた状態で交互に積層した層状構造を備える。 The electrode assembly 12 includes a positive electrode 21 as a plurality of sheet-shaped positive electrodes and a negative electrode 22 as a plurality of sheet-shaped negative electrodes. The electrode assembly 12 has a layered structure in which a separator 23 is interposed between the positive electrode 21 and the negative electrode 22 so as to be insulated and alternately laminated.

正極電極２１及び負極電極２２は、矩形シート状の金属箔２４を備える。正極電極２１の金属箔２４は、例えばアルミニウム箔であり、負極電極２２の金属箔２４は、例えば銅箔である。正極電極２１及び負極電極２２は、金属箔２４の両面に存在する活物質層２５を備える。活物質層２５は、極性に応じた活物質、導電材、及びバインダを含む。正極電極２１及び負極電極２２は、一対の長辺に沿う縁部のうち一方の縁部の一部から突出した矩形状のタブ２６を備える。本実施形態では、タブ２６の長手方向は、縁部からのタブ２６の突出方向と一致する。タブ２６は、活物質層２５が存在せず、金属箔２４が露出する未塗工部である。 The positive electrode 21 and the negative electrode 22 include a rectangular sheet-shaped metal foil 24. The metal foil 24 of the positive electrode 21 is, for example, an aluminum foil, and the metal foil 24 of the negative electrode 22 is, for example, a copper foil. The positive electrode 21 and the negative electrode 22 include an active material layer 25 existing on both sides of the metal foil 24. The active material layer 25 contains an active material, a conductive material, and a binder depending on the polarity. The positive electrode 21 and the negative electrode 22 include a rectangular tab 26 protruding from a part of one of the edges along the pair of long sides. In the present embodiment, the longitudinal direction of the tab 26 coincides with the protruding direction of the tab 26 from the edge portion. The tab 26 is an uncoated portion where the active material layer 25 does not exist and the metal foil 24 is exposed.

電極組立体１２は、各正極電極２１のタブ２６が正極電極２１、負極電極２２、及びセパレータ２３が積層される方向の一端に集箔されて積層された未塗工部群としてのタブ群１８を備える。同様に、電極組立体１２は、各負極電極２２のタブ２６が正極電極２１、負極電極２２、及びセパレータ２３が積層される方向の一端に集箔されて積層された未塗工部群としてのタブ群１８を備える。タブ２６が積層される方向を積層方向とする。各タブ群１８は、電極組立体１２において蓋１４と対向している端面１２ａに存在する。電極組立体１２は、タブ２６の突出方向におけるタブ群１８の基端部及び先端部が折り曲げられた状態でケース１１に収容される。なお、図３以降では、説明の便宜上、タブ群１８を折り曲げずに延ばした状態で図示している。 In the electrode assembly 12, the tabs 26 of each positive electrode 21 are collected and laminated at one end in the direction in which the positive electrode 21, the negative electrode 22, and the separator 23 are laminated, and the tab group 18 as an uncoated portion group is laminated. To prepare for. Similarly, the electrode assembly 12 is provided as an uncoated portion group in which the tab 26 of each negative electrode 22 is laminated by collecting foil at one end in the direction in which the positive electrode 21, the negative electrode 22, and the separator 23 are laminated. A tab group 18 is provided. The direction in which the tabs 26 are laminated is defined as the stacking direction. Each tab group 18 exists on the end face 12a facing the lid 14 in the electrode assembly 12. The electrode assembly 12 is housed in the case 11 in a state where the base end portion and the tip end portion of the tab group 18 in the protruding direction of the tab 26 are bent. In addition, in FIG. 3 and later, for convenience of explanation, the tab group 18 is shown in an extended state without being bent.

図３（ａ）及び図３（ｂ）に示すように、二次電池１０は、溶接部３１を備える。図３（ａ）に示すように、溶接部３１は、積層方向全てのタブ２６をレーザ溶接して形成されている。なお、タブ群１８の積層方向を上下方向とし、タブ群１８の積層方向一端を下端とするとともに、積層方向他端を上端とする。タブ群１８を積層方向他端側（上側）から見たとき、溶接部３１は直線的に延びる帯状である。溶接部３１の長手は、タブ２６の短手方向に延びる。溶接部３１の長手方向への長さは、例えば、タブ２６の短手方向への長さが２２ｍｍであれば１０ｍｍに設定され、溶接部３１の短手方向への長さは例えば１．０ｍｍに設定される。なお、溶接部３１の長手方向への長さは、タブ２６の短手方向への長さの範囲内であれば適宜変更してもよいし、溶接部３１の短手方向への長さは、タブ２６の長手方向への長さの範囲内であれば適宜変更してもよい。 As shown in FIGS. 3A and 3B, the secondary battery 10 includes a welded portion 31. As shown in FIG. 3A, the welded portion 31 is formed by laser welding tabs 26 in all the stacking directions. The stacking direction of the tab group 18 is the vertical direction, one end of the tab group 18 in the stacking direction is the lower end, and the other end of the stacking direction is the upper end. When the tab group 18 is viewed from the other end side (upper side) in the stacking direction, the welded portion 31 has a band shape extending linearly. The length of the welded portion 31 extends in the lateral direction of the tab 26. The length of the welded portion 31 in the longitudinal direction is set to, for example, 10 mm if the length of the tab 26 in the lateral direction is 22 mm, and the length of the welded portion 31 in the lateral direction is, for example, 1.0 mm. Is set to. The length of the welded portion 31 in the longitudinal direction may be appropriately changed as long as it is within the range of the length of the tab 26 in the lateral direction, and the length of the welded portion 31 in the lateral direction may be appropriately changed. , If it is within the range of the length of the tab 26 in the longitudinal direction, it may be changed as appropriate.

なお、図３（ｃ）に示すように、溶接部３１は、スポット径５０μｍのレーザ光Ｒを、タブ２６の長手方向（溶接部３１の短手方向）へ往復させながら、タブ２６の短手方向（溶接部３１の長手方向）に移動させて形成されている。本実施形態では、溶接部３１の長手方向は、レーザ光Ｒの進行方向であり、溶接部３１の短手方向は、進行方向に対する直交方向である。 As shown in FIG. 3C, the welded portion 31 reciprocates the laser beam R having a spot diameter of 50 μm in the longitudinal direction of the tab 26 (the lateral direction of the welded portion 31) while reciprocating the short side of the tab 26. It is formed by moving in a direction (longitudinal direction of the welded portion 31). In the present embodiment, the longitudinal direction of the welded portion 31 is the traveling direction of the laser beam R, and the lateral direction of the welded portion 31 is the direction orthogonal to the traveling direction.

次に、溶接用治具を用いた溶接部の形成方法について説明する。
溶接部の形成方法は、集箔工程、加圧工程及び溶接工程を備える。
集箔工程は、電極組立体１２が備える複数枚のタブ２６を集箔してタブ群１８を形成する工程である。集箔工程は、図５又は図６に示すように、作業台Ｓに載置された導電部材１７上に、電極組立体１２の全てのタブ２６を配置する。すなわち、積層方向一端のタブ２６より外側（下側）に導電部材１７を配置する。 Next, a method of forming a welded portion using a welding jig will be described.
The method for forming the welded portion includes a foil collecting step, a pressurizing step, and a welding step.
The foil collecting step is a step of collecting a plurality of tabs 26 included in the electrode assembly 12 to form a tab group 18. In the foil collecting step, as shown in FIG. 5 or FIG. 6, all the tabs 26 of the electrode assembly 12 are arranged on the conductive member 17 placed on the work table S. That is, the conductive member 17 is arranged outside (lower side) of the tab 26 at one end in the stacking direction.

なお、導電部材１７は、既に電極端子１５に接合されるとともに、その電極端子１５は蓋１４に締結されており、蓋１４に導電部材１７が一体化されている。よって、図６に示すように、導電部材１７は蓋１４から若干離れた状態で片持ち支持されている。導電部材１７の上にタブ２６が配置された状態では、全てのタブ２６は、蓋１４に片持ち支持された導電部材１７の上に配置される。次に、図示しない集箔装置によって、タブ２６を挟んだ導電部材１７の反対側（積層方向他端側）から全てのタブ２６を押圧して集箔し、タブ群１８を形成する。 The conductive member 17 is already joined to the electrode terminal 15, and the electrode terminal 15 is fastened to the lid 14, and the conductive member 17 is integrated with the lid 14. Therefore, as shown in FIG. 6, the conductive member 17 is cantilevered and supported in a state slightly separated from the lid 14. In the state where the tabs 26 are arranged on the conductive member 17, all the tabs 26 are arranged on the conductive member 17 cantilevered and supported by the lid 14. Next, by a foil collecting device (not shown), all the tabs 26 are pressed from the opposite side (the other end side in the stacking direction) of the conductive member 17 sandwiching the tabs 26 to collect the tabs, and the tab group 18 is formed.

加圧工程は、タブ群１８を積層方向他端から加圧する工程である。加圧工程には、溶接用治具５０が用いられる。ここで、溶接用治具５０について説明する。
溶接用治具５０は、セラミックス製であり、セラミックスとしてはマシナブルセラミックスや窒化ケイ素などが挙げられる。なお、マシナブルセラミックスは、雲母などを複合した機械切削加工しやすい快削性セラミックスのことである。本実施形態では、マシナブルセラミックスとして、熱伝導率が低く、かつ耐熱衝撃性が高いものを使用しており、例えば、ＳｉＯ２・ＡｌＯ２を主成分としたホトベール（登録商標）や、ＡｌＮ・ＢＮを主成分としたものシェイパルＭソフト（登録商標）が挙げられる。 The pressurizing step is a step of pressurizing the tab group 18 from the other end in the stacking direction. A welding jig 50 is used in the pressurizing step. Here, the welding jig 50 will be described.
The welding jig 50 is made of ceramics, and examples of the ceramics include machinable ceramics and silicon nitride. The machinable ceramics are free-cutting ceramics that are easy to machine-cut by combining mica and the like. In this embodiment, as machinable ceramics, those having low thermal conductivity and high thermal impact resistance are used, for example, Hotvale (registered trademark) containing SiO 2 and AlO 2 as main components, and AlN. Shapeal M software (registered trademark) containing BN as a main component can be mentioned.

図４（ａ）又は図４（ｂ）に示すように、溶接用治具５０は、四角筒状である。溶接用治具５０において、四角筒の中心軸Ｌの延びる方向を軸方向とする。溶接用治具５０は、軸方向の一端側に四角筒状の治具本体５１を備え、軸方向の他端側に四角筒状の接触部５２を備える。よって、接触部５２は、治具本体５１に対し、軸方向に連設されている。溶接用治具５０は、軸方向に貫通する貫通孔５３を備える。貫通孔５３は、レーザ溶接の際に、レーザ光Ｒを通過させる。よって、溶接部３１は、タブ群１８において、溶接用治具５０で囲まれた場所に形成される。治具本体５１及び接触部５２は、軸方向に見た平面視で四角枠状であり、貫通孔５３は平面視矩形状である。貫通孔５３は、治具本体５１の内側面及び接触部５２の内側面によって区画されている。貫通孔５３の長手方向への長さ、及び短手方向への長さは、軸方向に同じである。 As shown in FIG. 4A or FIG. 4B, the welding jig 50 has a square cylinder shape. In the welding jig 50, the extending direction of the central axis L of the square cylinder is defined as the axial direction. The welding jig 50 includes a square cylinder-shaped jig body 51 on one end side in the axial direction, and a square cylinder-shaped contact portion 52 on the other end side in the axial direction. Therefore, the contact portion 52 is continuously provided in the axial direction with respect to the jig main body 51. The welding jig 50 includes a through hole 53 penetrating in the axial direction. The through hole 53 allows the laser beam R to pass through during laser welding. Therefore, the welded portion 31 is formed in the tab group 18 at a place surrounded by the welding jig 50. The jig main body 51 and the contact portion 52 have a square frame shape in a plan view in the axial direction, and the through hole 53 has a rectangular shape in a plan view. The through hole 53 is partitioned by the inner surface of the jig main body 51 and the inner surface of the contact portion 52. The length of the through hole 53 in the longitudinal direction and the length in the lateral direction are the same in the axial direction.

図７に示すように、接触部５２は、四角枠の長手方向に延び、かつ互いに対向する一対の第１押圧部５２ａと、四角枠の短手方向に延び、かつ互いに対向する一対の第２押圧部５２ｂとを有する。平面視において、第１押圧部５２ａ及び第２押圧部５２ｂは直線状に延びる。一対の第１押圧部５２ａの長手方向一端部に、一方の第２押圧部５２ｂが繋がり、一対の第１押圧部５２ａの長手方向他端部に、他方の第２押圧部５２ｂが繋がっている。 As shown in FIG. 7, the contact portions 52 extend in the longitudinal direction of the square frame and face each other with a pair of first pressing portions 52a and a pair of second pressing portions 52a extending in the lateral direction of the square frame and facing each other. It has a pressing portion 52b. In a plan view, the first pressing portion 52a and the second pressing portion 52b extend linearly. One second pressing portion 52b is connected to one end in the longitudinal direction of the pair of first pressing portions 52a, and the other second pressing portion 52b is connected to the other end in the longitudinal direction of the pair of first pressing portions 52a. ..

図５又は図６に示すように、上記構成の溶接用治具５０は、積層方向他端（上端）の未塗工部であるタブ２６に載せられるとともに、タブ群１８を積層方向に加圧するために使用される。なお、図７に示すように、溶接部３１は、タブ２６の短手方向に長手が延びる形状に形成される。すなわち、溶接部３１は、溶接用治具５０の貫通孔５３の長手方向に長手が延びるように、溶接用治具５０の内側で形成される。このため、溶接用治具５０は、第１押圧部５２ａの長手が、タブ２６の短手方向に延びる状態でタブ２６に載せられる。 As shown in FIG. 5 or 6, the welding jig 50 having the above configuration is placed on the tab 26 which is the uncoated portion at the other end (upper end) in the stacking direction, and the tab group 18 is pressed in the stacking direction. Used for. As shown in FIG. 7, the welded portion 31 is formed in a shape whose length extends in the lateral direction of the tab 26. That is, the welding portion 31 is formed inside the welding jig 50 so that the length extends in the longitudinal direction of the through hole 53 of the welding jig 50. Therefore, the welding jig 50 is placed on the tab 26 in a state where the length of the first pressing portion 52a extends in the lateral direction of the tab 26.

一対の第１押圧部５２ａの対向面同士の間隔Ｋ１は、５０μｍより広く５ｍｍ以下に設定されている。なお、第１押圧部５２ａの間隔Ｋ１とは、第１押圧部５２ａの対向面同士を最短距離で結ぶ直線の長さである。上述したように、溶接部３１は、スポット径５０μｍのレーザ光Ｒを進行方向に移動させて形成されることから、レーザ光Ｒを溶接部３１の短手方向に往復させなければ、溶接部３１の短手方向への長さの最小値は、スポット径となる。第１押圧部５２ａの間隔Ｋ１が５０μｍ以下であると、レーザ溶接時に、第１押圧部５２ａそれぞれにレーザ光Ｒが接触してしまい好ましくない。よって、第１押圧部５２ａの間隔Ｋ１は、５０μｍより広く設定されている。 The distance K1 between the facing surfaces of the pair of first pressing portions 52a is set to be wider than 50 μm and 5 mm or less. The distance K1 between the first pressing portions 52a is the length of a straight line connecting the facing surfaces of the first pressing portions 52a with each other at the shortest distance. As described above, since the welded portion 31 is formed by moving the laser beam R having a spot diameter of 50 μm in the traveling direction, the welded portion 31 must be reciprocated in the lateral direction of the welded portion 31 unless the laser beam R is reciprocated in the lateral direction of the welded portion 31. The minimum value of the length in the lateral direction is the spot diameter. If the distance K1 between the first pressing portions 52a is 50 μm or less, the laser beam R comes into contact with each of the first pressing portions 52a during laser welding, which is not preferable. Therefore, the distance K1 of the first pressing portion 52a is set wider than 50 μm.

また、溶接用治具５０によってタブ群１８を加圧したとき、積層方向に隣り合うタブ２６同士が離れることを抑制するため、すなわち、タブ２６同士を密着させるためには、第１押圧部５２ａの間隔Ｋ１が５ｍｍ以下であることが好ましいことが、発明者らによって確認されている。すなわち、第１押圧部５２ａの間隔Ｋ１が５ｍｍより広くなると、溶接用治具５０によってタブ群１８を加圧しても、積層方向に隣り合うタブ２６同士を密着させることが困難になり、好ましくない。よって、第１押圧部５２ａの間隔は５ｍｍ以下に設定されている。 Further, when the tab group 18 is pressurized by the welding jig 50, the first pressing portion 52a is used to prevent the adjacent tabs 26 from separating from each other in the stacking direction, that is, to bring the tabs 26 into close contact with each other. It has been confirmed by the inventors that the distance K1 is preferably 5 mm or less. That is, when the distance K1 between the first pressing portions 52a is wider than 5 mm, even if the tab group 18 is pressed by the welding jig 50, it becomes difficult to bring the tabs 26 adjacent to each other in the stacking direction into close contact with each other, which is not preferable. .. Therefore, the distance between the first pressing portions 52a is set to 5 mm or less.

また、上記のように、溶接部３１は、レーザ光Ｒを溶接用治具５０の内側で進行方向に移動させて形成されるが、レーザ光Ｒの進行方向は、溶接部３１の長手方向である。よって、溶接部３１の進行方向に対する直交方向に離れて一対の第１押圧部５２ａが位置することとなる。したがって、接触部５２の一対の第１押圧部５２ａは、レーザ光Ｒの進行方向に対する直交方向に離れて対向する部位となる。 Further, as described above, the welded portion 31 is formed by moving the laser beam R inside the welding jig 50 in the traveling direction, but the traveling direction of the laser beam R is in the longitudinal direction of the welded portion 31. be. Therefore, the pair of first pressing portions 52a are located apart from each other in the direction orthogonal to the traveling direction of the welded portion 31. Therefore, the pair of first pressing portions 52a of the contact portions 52 are portions facing each other apart in the direction orthogonal to the traveling direction of the laser beam R.

なお、第１押圧部５２ａの厚みは、０．１〜６ｍｍに設定されるのが好ましい。これは、例えば、導電部材１７の短手方向への長さが１７ｍｍの場合、タブ群１８において、溶接部３１を形成できる領域、すなわち導電部材１７と重なる領域での寸法も１７ｍｍとなる。導電部材１７と重なるタブ群１８の領域において、間隔Ｋ１の最大値である５ｍｍを確保し、かつ一対の第１押圧部５２ａをタブ２６に接触させるため、（１７−５）÷２から、６ｍｍが最大値として算出される。一方、最小値０．１ｍｍは、タブ群１８を加圧するために必要な最小限の厚みとして設定される。 The thickness of the first pressing portion 52a is preferably set to 0.1 to 6 mm. For example, when the length of the conductive member 17 in the lateral direction is 17 mm, the dimension of the tab group 18 in the region where the welded portion 31 can be formed, that is, the region overlapping with the conductive member 17 is also 17 mm. In the region of the tab group 18 overlapping with the conductive member 17, the maximum value of the interval K1 of 5 mm is secured, and the pair of first pressing portions 52a is brought into contact with the tab 26, so that (17-5) ÷ 2 to 6 mm. Is calculated as the maximum value. On the other hand, the minimum value of 0.1 mm is set as the minimum thickness required to pressurize the tab group 18.

また、一対の第２押圧部５２ｂの対向面同士の間隔Ｋ２は、レーザ光Ｒが第２押圧部５２ｂに接触しないように、溶接部３１の長手方向への長さに応じて設定される。例えば、第２押圧部５２ｂの間隔Ｋ２は、溶接部３１の長手方向の端と、第２押圧部５２ｂの内面との間に、一定寸法（例えば２ｍｍ）以上の隙間が形成されるように設定される。なお、第２押圧部５２ｂの間隔Ｋ２とは、第２押圧部５２ｂの対向面同士を最短距離で結ぶ直線の長さである。 Further, the distance K2 between the facing surfaces of the pair of second pressing portions 52b is set according to the length of the welded portion 31 in the longitudinal direction so that the laser beam R does not come into contact with the second pressing portion 52b. For example, the distance K2 of the second pressing portion 52b is set so that a gap having a certain dimension (for example, 2 mm) or more is formed between the longitudinal end of the welded portion 31 and the inner surface of the second pressing portion 52b. Will be done. The distance K2 between the second pressing portions 52b is the length of a straight line connecting the facing surfaces of the second pressing portions 52b at the shortest distance.

溶接用治具５０は、接触部５２の端面（下面）にタブ２６への接触面５４を備える。接触面５４は、一対の第１押圧部５２ａの端面と一対の第２押圧部５２ｂの端面から四角枠状に形成されている。接触面５４の面積は、治具本体５１の端面（上面）の面積より小さい。 The welding jig 50 includes a contact surface 54 for the tab 26 on the end surface (lower surface) of the contact portion 52. The contact surface 54 is formed in a square frame shape from the end faces of the pair of first pressing portions 52a and the end faces of the pair of second pressing portions 52b. The area of the contact surface 54 is smaller than the area of the end surface (upper surface) of the jig body 51.

図５又は図６に示すように、溶接用治具５０は、流体シリンダ６０に連結され、溶接用治具５０は、流体シリンダ６０によって上下動可能に支持されている。流体シリンダ６０はエアシリンダである。流体シリンダ６０は、シリンダチューブ６０ａと、シリンダチューブ６０ａの下端に対し出没するシリンダロッド６０ｂを備える。シリンダチューブ６０ａ内には、ピストン６０ｃが移動可能に収容され、シリンダロッド６０ｂの一端はピストン６０ｃに連結されている。シリンダチューブ６０ａからのシリンダロッド６０ｂの突出端となる他端には、溶接用治具５０が連結されている。そして、流体シリンダ６０により、タブ群１８に載せた溶接用治具５０をタブ群１８に向けて押圧することで、溶接用治具５０によってタブ群１８を積層方向に加圧できる。 As shown in FIG. 5 or FIG. 6, the welding jig 50 is connected to the fluid cylinder 60, and the welding jig 50 is supported by the fluid cylinder 60 so as to be vertically movable. The fluid cylinder 60 is an air cylinder. The fluid cylinder 60 includes a cylinder tube 60a and a cylinder rod 60b that appears and disappears from the lower end of the cylinder tube 60a. A piston 60c is movably housed in the cylinder tube 60a, and one end of the cylinder rod 60b is connected to the piston 60c. A welding jig 50 is connected to the other end of the cylinder rod 60b, which is a protruding end from the cylinder tube 60a. Then, by pressing the welding jig 50 mounted on the tab group 18 toward the tab group 18 by the fluid cylinder 60, the tab group 18 can be pressed in the stacking direction by the welding jig 50.

そして、溶接用治具５０によってタブ群１８を加圧することで、タブ群１８において、溶接部３１となる箇所の周囲を加圧できる。一対の第１押圧部５２ａにより、レーザ光Ｒの進行方向に対する直交方向に離れて対向する部位を加圧でき、一対の第２押圧部５２ｂにより、レーザ光Ｒの進行方向の両側に離れて対向する部位を加圧できる。溶接用治具５０によってタブ群１８を加圧することで、各タブ２６について、溶接部３１となる箇所の周囲を突っ張った状態にでき、溶接部３１となる箇所にあるタブ２６の弛みを抑制できる。 Then, by pressurizing the tab group 18 with the welding jig 50, it is possible to pressurize the periphery of the portion to be the welded portion 31 in the tab group 18. The pair of first pressing portions 52a can pressurize the portions facing each other in the direction orthogonal to the traveling direction of the laser beam R, and the pair of second pressing portions 52b can pressurize the portions facing each other in the traveling direction of the laser beam R. It is possible to pressurize the part to be treated. By pressurizing the tab group 18 with the welding jig 50, each tab 26 can be in a stretched state around the portion to be the welded portion 31, and slackening of the tab 26 at the portion to be the welded portion 31 can be suppressed. ..

タブ群１８の加圧力は、１〜２ｋｇｆ／ｃｍ２となるように流体シリンダ６０の圧力を調節する。なお、加圧力が１ｋｇｆ／ｃｍ２より小さくなると、各タブ２６を突っ張った状態にしにくく、好ましくない。一方、加圧力が２ｋｇｆ／ｃｍ２より大きくなると、タブ群１８の外側（下側）に配置され、かつ蓋１４に片持ち支持された導電部材１７において、蓋１４に支持されていない部位が撓む虞があり、好ましくない。 The pressure of the fluid cylinder 60 is adjusted so that the pressing force of the tab group 18 is 1 to 2 kgf / cm 2. If the pressing force is smaller than 1 kgf / cm 2 , it is difficult to make each tab 26 in a stretched state, which is not preferable. On the other hand, when the pressing force becomes larger than 2 kgf / cm 2, in the conductive member 17 arranged on the outside (lower side) of the tab group 18 and cantilevered and supported by the lid 14, the portion not supported by the lid 14 bends. It is not preferable because it may cause a problem.

そして、加圧工程では、タブ群１８において積層方向他端に位置するタブ２６に溶接用治具５０を載せ、接触面５４を積層方向他端のタブ２６に接触させる。このとき、タブ２６において、溶接部３１が形成される箇所を囲む位置に接触面５４を接触させる。次に、流体シリンダ６０によって、溶接用治具５０をタブ群１８に向けて移動させる。すると、タブ群１８において、溶接部３１となる箇所の周囲が溶接用治具５０によって加圧される。その結果、タブ群１８において、積層方向に隣り合うタブ２６同士は密着した状態となる。 Then, in the pressurizing step, the welding jig 50 is placed on the tab 26 located at the other end in the stacking direction in the tab group 18, and the contact surface 54 is brought into contact with the tab 26 at the other end in the stacking direction. At this time, the contact surface 54 is brought into contact with the tab 26 at a position surrounding the portion where the welded portion 31 is formed. Next, the welding jig 50 is moved toward the tab group 18 by the fluid cylinder 60. Then, in the tab group 18, the periphery of the portion to be the welded portion 31 is pressurized by the welding jig 50. As a result, in the tab group 18, the tabs 26 adjacent to each other in the stacking direction are in close contact with each other.

図６に示すように、溶接工程は、溶接部３１を形成する工程である。溶接工程はレーザ溶接によって行われる。レーザ照射装置６２によって、タブ群１８を加圧している溶接用治具５０の貫通孔５３にレーザ光Ｒを照射し、貫通孔５３にレーザ光Ｒを通過させる。つまり、タブ群１８の積層方向他端のタブ２６にレーザ光Ｒを照射する。そして、図３（ｃ）に示すように、レーザ光Ｒを進行方向に移動させる。このとき、溶接用治具５０によってタブ群１８を加圧しておくことにより、タブ群１８において、第１押圧部５２ａ同士の間では、各タブ２６が引っ張られ、突っ張った状態となる。その結果、積層方向に隣り合うタブ２６同士が密着した状態でレーザ溶接が行われ、溶接部３１が形成される。 As shown in FIG. 6, the welding step is a step of forming the welded portion 31. The welding process is performed by laser welding. The laser irradiation device 62 irradiates the through hole 53 of the welding jig 50 pressurizing the tab group 18 with the laser beam R, and allows the laser beam R to pass through the through hole 53. That is, the laser beam R is applied to the tab 26 at the other end of the tab group 18 in the stacking direction. Then, as shown in FIG. 3C, the laser beam R is moved in the traveling direction. At this time, by pressurizing the tab group 18 with the welding jig 50, each tab 26 is pulled and stretched between the first pressing portions 52a in the tab group 18. As a result, laser welding is performed in a state where the tabs 26 adjacent to each other in the stacking direction are in close contact with each other, and the welded portion 31 is formed.

次に、本実施形態の作用効果を記載する。
（１）溶接用治具５０の接触部５２のうち、一対の第１押圧部５２ａの間隔Ｋ１を５０μｍより広く、かつ５ｍｍ以下に設定した。このため、溶接用治具５０によりタブ群１８を加圧したとき、タブ２６において、一対の第１押圧部５２ａで挟まれた部分を突っ張らせることができる。その結果、積層方向に隣り合うタブ２６同士を密着させた状態としながら、溶接用治具５０にレーザ光Ｒを通過させることで溶接部３１を形成できる。このため、積層方向に溶融が進みやすくなり、レーザ光Ｒの照射位置に近いタブ２６にエネルギーが集中することが抑制される。よって、保護板を用いることなくタブ２６の破れの発生を抑制できる。その結果として、タブ群１８と導電部材１７のレーザ溶接の度に保護板を用いる場合と比べると、溶接工程が容易となるとともに、二次電池１０の部品点数の増加もない。 Next, the action and effect of this embodiment will be described.
(1) Of the contact portions 52 of the welding jig 50, the distance K1 between the pair of first pressing portions 52a is set to be wider than 50 μm and 5 mm or less. Therefore, when the tab group 18 is pressurized by the welding jig 50, the portion sandwiched between the pair of first pressing portions 52a can be stretched on the tab 26. As a result, the welded portion 31 can be formed by passing the laser beam R through the welding jig 50 while keeping the tabs 26 adjacent to each other in close contact with each other in the stacking direction. Therefore, melting tends to proceed in the stacking direction, and concentration of energy on the tab 26 near the irradiation position of the laser beam R is suppressed. Therefore, it is possible to suppress the occurrence of tearing of the tab 26 without using a protective plate. As a result, the welding process becomes easier and the number of parts of the secondary battery 10 does not increase as compared with the case where the protective plate is used for each laser welding of the tab group 18 and the conductive member 17.

（２）接触面５４の面積を、治具本体５１の上面の面積より小さくし、タブ２６に接触する面積を小さくするようにした。このため、例えば、溶接用治具５０を、タブ２６における溶接部３１の周囲全面に接触させる場合と比べると、加圧力を溶接部３１の周囲に集中させ、流体シリンダ６０によって溶接用治具５０を押圧したときに生じる加圧力を大きくできる。 (2) The area of the contact surface 54 is made smaller than the area of the upper surface of the jig main body 51, and the area in contact with the tab 26 is made smaller. Therefore, for example, as compared with the case where the welding jig 50 is brought into contact with the entire periphery of the welding portion 31 in the tab 26, the pressing force is concentrated around the welding portion 31, and the welding jig 50 is provided by the fluid cylinder 60. The pressure generated when pressing can be increased.

（３）接触部５２は四角筒状であり、溶接部３１を取り囲む。このため、レーザ溶接の際に生じたスパッタが接触部５２より外側に飛散することを抑止できる。
（４）接触部５２は四角筒状であり、溶接部３１を取り囲む。このため、タブ群１８において、溶接部３１となる箇所を環状に加圧でき、タブ２６を突っ張った状態にしやすい。 (3) The contact portion 52 has a square cylindrical shape and surrounds the welded portion 31. Therefore, it is possible to prevent the spatter generated during laser welding from scattering outside the contact portion 52.
(4) The contact portion 52 has a square cylindrical shape and surrounds the welded portion 31. Therefore, in the tab group 18, the portion to be the welded portion 31 can be pressurized in an annular shape, and the tab 26 can be easily put into a stretched state.

（５）溶接用治具５０は、熱伝導率が低く、耐熱衝撃性の高いセラミックス製である。このため、レーザ溶接時の熱の放熱を溶接用治具５０で抑制できる。また、レーザ溶接時の熱によって溶接用治具５０が急激に温度上昇しても溶接用治具５０が割れたり、クラックが入ったりすることを抑制できる。 (5) The welding jig 50 is made of ceramics having low thermal conductivity and high thermal impact resistance. Therefore, heat dissipation during laser welding can be suppressed by the welding jig 50. Further, even if the temperature of the welding jig 50 suddenly rises due to the heat during laser welding, it is possible to prevent the welding jig 50 from cracking or cracking.

（６）溶接用治具５０によってタブ群１８を加圧する際、加圧力を１〜２ｋｇｆ／ｃｍ２に設定した。このため、タブ群１８の下に配置された導電部材１７を撓ませることなく、タブ２６の弛みを抑制できる。 (6) When the tab group 18 was pressurized by the welding jig 50, the pressing force was set to 1 to 2 kgf / cm 2. Therefore, the slackening of the tab 26 can be suppressed without bending the conductive member 17 arranged under the tab group 18.

なお、上記実施形態は、以下のように変更してもよい。
○ 溶接用治具５０でタブ群１８を加圧した際、各タブ２６を突っ張った状態にできれば、溶接用治具５０によってタブ群１８を加圧する際の加圧力を１〜２ｋｇｆ／ｃｍ２以外に設定してもよい。 The above embodiment may be modified as follows.
○ When the tab group 18 is pressed by the welding jig 50, if each tab 26 can be in a stretched state, the pressing force when the tab group 18 is pressed by the welding jig 50 is other than 1 to 2 kgf / cm 2. May be set to.

○ 接触部５２は、四角筒状でなくてもよい。例えば、接触部５２は、タブ群１８において、溶接部３１となる箇所を取り囲むことができれば、円筒状、楕円筒状、六角筒状等に変更してもよい。 ○ The contact portion 52 does not have to have a square cylinder shape. For example, the contact portion 52 may be changed to a cylindrical shape, an elliptical tubular shape, a hexagonal tubular shape, or the like as long as it can surround the portion to be the welded portion 31 in the tab group 18.

○ 溶接用治具５０の治具本体５１と接触部５２は別体であってもよい。
○ 接触部５２は筒状でなくてもよい。例えば、接触部は、レーザ光Ｒの進行方向に対する直交方向に離れて対向する部位として一対の第１押圧部５２ａだけを備える構成であってもよい。要は、接触部は、レーザ光Ｒの進行方向に対する直交方向に離れて対向する部位を備えていれば平面視Ｃ状やコ字状にしてもよい。 ○ The jig body 51 and the contact portion 52 of the welding jig 50 may be separate bodies.
○ The contact portion 52 does not have to be cylindrical. For example, the contact portion may be configured to include only a pair of first pressing portions 52a as portions facing away from each other in the direction orthogonal to the traveling direction of the laser beam R. In short, the contact portion may be C-shaped or U-shaped in a plan view as long as it has a portion facing away from each other in the direction orthogonal to the traveling direction of the laser beam R.

○ 電極組立体１２は、巻回型の電極組立体でもよい。図示しないが、巻回型の電極組立体は、長尺帯状の正極電極と長尺帯状の負極電極とが絶縁された状態で巻回された層状構造を有する。正極電極及び負極電極はそれぞれ、一対の長辺に沿う縁部のうち一方の縁部に活物質層が存在せず、金属箔が露出した帯状の未塗工部を備える。電極組立体は、帯状の未塗工部が同じ極性同士で積層された未塗工部群を備える。正極の未塗工部群は、巻回軸線の一端に存在し、負極の未塗工部群は、巻回軸線の他端に存在する。 ○ The electrode assembly 12 may be a winding type electrode assembly. Although not shown, the wound electrode assembly has a layered structure in which a long strip-shaped positive electrode and a long strip-shaped negative electrode are insulated from each other. Each of the positive electrode and the negative electrode has a strip-shaped uncoated portion in which the active material layer does not exist at one of the edges along the pair of long sides and the metal foil is exposed. The electrode assembly includes a group of uncoated portions in which strip-shaped uncoated portions are laminated with the same polarity. The uncoated portion group of the positive electrode exists at one end of the winding axis, and the uncoated portion group of the negative electrode exists at the other end of the winding axis.

○ 正極電極２１及び負極電極２２において、活物質層２５は金属箔２４の片面に存在してもよい。
○ 正極電極２１及び負極電極２２の未塗工部は、タブ２６に限定されない。例えば、正極電極２１及び負極電極２２の一対の長辺に沿う縁部のうちの一方の縁部から金属箔２４を露出させるとともに、その露出した金属箔の一部からタブ２６を突出させる。そして、縁部に沿う金属箔とタブ２６を未塗工部としてもよい。また、正極電極２１及び負極電極２２の一対の長辺に沿う縁部のうちの一方の縁部から金属箔２４を露出させ、その露出した部分のみを未塗工部としてもよい。 ○ In the positive electrode 21 and the negative electrode 22, the active material layer 25 may be present on one side of the metal foil 24.
○ The uncoated portion of the positive electrode 21 and the negative electrode 22 is not limited to the tab 26. For example, the metal foil 24 is exposed from one of the edges of the pair of long sides of the positive electrode 21 and the negative electrode 22, and the tab 26 is projected from a part of the exposed metal foil. Then, the metal foil and the tab 26 along the edge portion may be used as the uncoated portion. Further, the metal foil 24 may be exposed from one of the edges of the pair of long sides of the positive electrode 21 and the negative electrode 22, and only the exposed portion may be an uncoated portion.

○ 溶接用治具５０は、マシナブルセラミックス以外のセラミックスであってもよいし、熱伝導率が低く、耐熱衝撃性の高い金属であってもよい。
○ 溶接部３１の長手は、タブ２６の長手方向に延びていてもよい。 ○ The welding jig 50 may be a ceramic other than the machinable ceramics, or may be a metal having a low thermal conductivity and a high thermal impact resistance.
○ The length of the welded portion 31 may extend in the longitudinal direction of the tab 26.

○ 溶接部３１の長手方向の長さは、適宜変更してよい。
○ 溶接部３１の形状は適宜変更してよい。
○ 蓄電装置は、例えばキャパシタなど、二次電池以外の蓄電装置にも適用可能である。 ○ The length of the welded portion 31 in the longitudinal direction may be appropriately changed.
○ The shape of the welded portion 31 may be changed as appropriate.
○ The power storage device can also be applied to a power storage device other than a secondary battery, such as a capacitor.

○ 二次電池１０は、リチウムイオン二次電池以外の他の二次電池であってもよい。要は、正極用の活物質と負極用の活物質との間をイオンが移動するとともに電荷の教授を行うものであればよい。 ○ The secondary battery 10 may be a secondary battery other than the lithium ion secondary battery. In short, it suffices as long as the ions move between the active material for the positive electrode and the active material for the negative electrode and the charge is taught.

Ｒ…レーザ光、Ｋ１…間隔、１０…蓄電装置としての二次電池、１２…電極組立体、１７…導電部材、１８…未塗工部群としてのタブ群、２１…正極の電極としての正極電極、２２…負極の電極としての負極電極、２４…金属箔、２５…活物質層、２６…未塗工部としてのタブ、３１…溶接部、５０…溶接用治具、５１…治具本体、５２…接触部、５３…貫通孔。 R ... Laser light, K1 ... Spacing, 10 ... Secondary battery as a power storage device, 12 ... Electrode assembly, 17 ... Conductive member, 18 ... Tab group as uncoated part group, 21 ... Positive electrode as positive electrode Electrode, 22 ... Negative electrode as negative electrode, 24 ... Metal foil, 25 ... Active material layer, 26 ... Tab as uncoated part, 31 ... Welding part, 50 ... Welding jig, 51 ... Jig body , 52 ... Contact part, 53 ... Through hole.

Claims (1)

金属箔の少なくとも片面に活物質層を有するとともに、前記活物質層が存在せず、前記金属箔が露出する未塗工部とを有する正極及び負極の電極が絶縁された状態で積層され、かつ前記未塗工部が同じ極性同士で積層された未塗工部群を備える電極組立体と、前記未塗工部群と接合された導電部材と、を備える蓄電装置において、前記導電部材と前記未塗工部群とをレーザ溶接した溶接部の形成方法であって、
前記未塗工部群の積層方向一端の未塗工部より外側に前記導電部材を配置し、
筒状の治具本体と、前記治具本体を軸方向に貫通し、レーザ光を通過させる貫通孔と、前記治具本体の軸方向に連設され、かつ前記レーザ光の進行方向に対する直交方向に５０μｍより広く５ｍｍ以下の間隔を空けた状態で対向する部位を備える接触部と、を有した溶接用治具を、前記未塗工部群の積層方向他端の未塗工部に直接接触させ、
前記積層方向他端の未塗工部に直接接触する前記接触部の端面の面積は、前記治具本体の端面の面積より小さくなっており、
前記溶接用治具により前記未塗工部群を積層方向に１〜２ｋｇｆ／ｃｍ ２ の加圧力で加圧した状態で、前記溶接用治具の貫通孔を通過するレーザ光を前記進行方向に移動させながら前記積層方向他端の未塗工部に直接照射することを特徴とする溶接部の形成方法。 The positive electrode and the negative electrode having an active material layer on at least one side of the metal foil and having an uncoated portion where the active material layer does not exist and the metal foil is exposed are laminated in an insulated state. In a power storage device including an electrode assembly having an uncoated portion group in which uncoated portions are laminated with the same polarity and a conductive member joined to the uncoated portion group, the conductive member and the above. It is a method of forming a welded part by laser welding an uncoated part group.
The conductive member is arranged outside the uncoated portion at one end in the stacking direction of the uncoated portion group.
A tubular jig body, a through hole that penetrates the jig body in the axial direction and allows laser light to pass through, and a series of holes connected in the axial direction of the jig body and in a direction orthogonal to the traveling direction of the laser light. the contact portion including a portion facing in a state spaced widely following interval 5mm from 50 [mu] m, a welding jig having a direct contact with the uncoated portion of the stacking direction end of the uncoated portion group Let me
The area of the end face of the contact portion that directly contacts the uncoated portion at the other end in the stacking direction is smaller than the area of the end face of the jig body.
In a state in which the pressurized the uncoated portion group under a pressure of 1~2kgf / cm 2 in the stacking direction by the welding jig, a laser beam passing through the through hole of the welding jig to the traveling direction A method for forming a welded portion, which comprises directly irradiating an uncoated portion at the other end in the stacking direction while moving the welded portion.
JP2017190088A 2017-09-29 2017-09-29 Welded part forming method Active JP6988335B2 (en)

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