WO2023054424A1

WO2023054424A1 - Weld structure, electronic component module, and welding method

Info

Publication number: WO2023054424A1
Application number: PCT/JP2022/036064
Authority: WO
Inventors: 道広佐々木; 満黒須
Original assignee: 日本ケミコン株式会社
Priority date: 2021-09-29
Filing date: 2022-09-28
Publication date: 2023-04-06
Also published as: JP2023049375A

Abstract

The purpose of the present disclosure is, for example, to reduce residual stress from welding and thereby suppress cracking at a weld structure.　A weld structure (2) comprises a first member (4) that has a first joining surface part (10), a second member (6) that has a second joining surface part (16), and a weld-solidified part (8) that is formed at the butted joining surface parts of the first member and the second member by welding. The weld-solidified part includes a first solidified part (20) that is on the outside and a second solidified part (22) that is on the inside.

Description

Welded structure, electronic component module and welding method

The technology of the present disclosure relates to a welded structure, an electronic component module, and a welding method. In this specification, claims and abstract, the term "welded structure" is used as a term encompassing the welded structure itself and the welded structure.

Welding is used to connect components, such as electrical connections in electronic components. For example, it is known that electrode terminals of a battery pack are welded to bus bars (for example, Patent Document 1). In electronic components, welding can reduce electrical resistance and suppress energy loss and heat generation compared to fastening with fastening members such as bolts and screws. However, welding is less easy to connect or separate than fastening with fastening members.

JP 2015-187910 A

By the way, the members used for welding are selected in consideration of selection items such as the use of the member, suitability for welding, and compatibility with the partner member to be welded. In the selection of members, for example, if the use of the member is set as a priority selection item, it may be necessary to compromise other selection items such as suitability for welding and compatibility with the mating member.

When a high-strength busbar is bolted to another member, the change in thickness of the busbar over time is small, and loosening of the bolt can be suppressed. However, when the strength of the bus bar increases, there is generally a problem that cracks are likely to occur due to welding. The term "strength" refers to the resistance of a material to deformation and breakage.

In electronic parts, large cracks in electrical connection members such as busbars, which are responsible for electrical connections, have the problem of causing adverse effects such as increased electrical resistance and heat generation when energized.

Patent Document 1 does not disclose or suggest such problems, and the configuration disclosed in Patent Document 1 cannot solve such problems.

Therefore, the first object of the present disclosure is, for example, to reduce residual stress due to welding and suppress cracks in the welded structure.

A second object of the present disclosure is, for example, to reduce residual stress due to welding and expand the types of members that can be used for welding.

A third objective of the present disclosure is to improve performance or specifications such as electrical properties, strength, hardness, durability, etc., in welded structures, taking advantage of, for example, expanding the range of usable members.

According to a first aspect of the present disclosure, a welded structure includes a first member having a first joint surface, a second member having a second joint surface, and the first member butted together. A weld solidified portion formed by welding on the joint surface portion of the second member, wherein the weld solidified portion includes a first solidified portion arranged on the outside and a second solidified portion arranged on the inside. including.

In the above-described welded structure, the second member may have a higher strength than the first member, and the welding center portion of the weld solidified portion may be abutting surfaces of the first member and the second member. may be arranged on the side of the first member with respect to.

In the above welded structure, the second member may further include a fastening portion that can be fastened with another member.

In the above welded structure, the cross-sectional width of the second solidified portion may be 10% or more and 70% or less of the cross-sectional width of the weld solidified portion.

In the above welded structure, the weld solidified portion may have an annular shape. In the specification and claims, the term "ring" denotes an object having a shape obtained by connecting the ends of a line or elongated surface. The ring may be a torus having a circular shape, or may have a shape other than a circular shape.

According to the second aspect of the present disclosure, the electronic component module has the welded structure.

According to a third aspect of the present disclosure, a welding method melts adjacent portions of a first member and a second member that are adjacent to each other by a first heating to form a melted portion, and and remelting or reheating a part of the molten portion by a second heating to form a first solidified portion arranged outside and a second solidified portion arranged inside forming a weld solidification comprising:

In the above welding method, the second member may have a higher strength than the first member, and the first heating may be applied to the abutting surfaces of the first member and the second member. It may be added to the first member side.

The welding method may further include forming a fastening portion that can be fastened with another member on the second member.

In the above welding method, the amount of heat applied by the second heating may be 9% or more and 50% or less of the amount of heat applied by the first heating.

In the above welding method, the first heating and the second heating may be applied circumferentially, and the weld solidified portion may have an annular shape.

In the welding method described above, the first member may be a terminal of an electronic component or a conductive member connectable to the electronic component. The second member may be an electrical connection member capable of electrically connecting the first member to another member.

According to the technology of the present disclosure, one of the following effects can be obtained.

(1) Since the weld solidified part includes the first solidified part arranged on the outside and the second solidified part arranged on the inside, the residual stress in the weld solidified part is suppressed, and the butt joint of the welded structure Cracking can be suppressed. Therefore, for example, in an electronic component, it is possible to suppress an increase in electrical resistance due to cracks and heat generation during energization.

(2) Since the residual stress in the solidified weld zone is suppressed, it is possible to expand the degree of freedom in the types of members connected by the butt joint.

(3) The members connected by the butt joint can be selected based, for example, on the application of the members, improving the performance or specifications of the welded structure. For example, in the welding structure of electronic components, it is possible to select low-resistance, high-strength members in consideration of electrical conductivity and fastening with other members.

It is a figure which shows an example of the welding structure which concerns on embodiment. It is a figure which shows an example of the cross section of a weld solidification part. It is a figure which shows an example of the welding method. It is a figure which shows an example of the electronic component which concerns on an Example. It is a figure which shows an example of an edge part bus-bar. It is a figure which shows an example of the welding structure which concerns on a modification. It is a figure which shows the modification of a welding method.

FIG. 1 shows an example of a welded structure according to an embodiment. FIG. 2 shows an example of a cross-section of a solidified weld, and shows a cross-section taken along the line II--II in A of FIG. The configurations shown in FIGS. 1 and 2 are examples, and the technology of the present disclosure is not limited to such configurations.

The welded structure 2 is formed by a welding technique such as laser welding. The welded structure 2 includes a first member 4 , a second member 6 and a weld solidification 8 .

The first member 4 is, for example, a terminal of an electronic component such as a power storage device module, or a conductive member connectable to the electronic component. The electronic component may be a single electronic component, or an electronic component module formed by assembling and connecting a plurality of electronic components. The first member 4 has, for example, a cylindrical shape or a substantially cylindrical shape, and has a first joint surface portion 10 on the end side surface. The first joint surface portion 10 forms a joint surface portion for the weld solidification portion 8 . The 1st member 4 contains metal, such as aluminum, an aluminum alloy, or stainless steel, for example. The first member 4 may be metal such as aluminum, aluminum alloy or stainless steel.

Aluminum is, for example, pure aluminum (1000 series material) with a purity of 99.0% or more, and has excellent workability, surface treatability, and corrosion resistance. Aluminum alloys include, for example, aluminum-copper (Al-Cu) alloys (2000 series materials), aluminum-manganese (Al-Mn) alloys (3000 series materials), aluminum-silicon (Al-Si) alloys (4000 series material), aluminum-magnesium (Al-Mg) alloy (5000 series material), aluminum-magnesium-silicon (Al-Mg-Si) alloy (6000 series material), aluminum-zinc-magnesium (Al-Zn-Mg ) series alloys (7000 series materials). Aluminum-copper alloys have high strength and excellent machinability. Aluminum-manganese alloys have workability, corrosion resistance, and higher strength than pure aluminum. Aluminum-silicon alloys have excellent heat resistance and wear resistance, and have a small coefficient of thermal expansion. Aluminum-magnesium alloys have excellent corrosion resistance, workability, and high strength. Aluminum-magnesium-silicon alloys have excellent corrosion resistance and high strength. Aluminum-zinc-magnesium based alloys have high strength.

The second member 6 is, for example, an electrical connection member such as a busbar, and can electrically connect the first member 4 to another member, for example. The second member 6 has, for example, a plate shape or approximately plate shape. The second member 6 contains, for example, a metal such as the already-described aluminum alloy or stainless steel. The second member 6 may be made of a metal such as the already-described aluminum alloy or stainless steel. The second member 6 is a member that suppresses deformation due to creep, for example. Creep is a phenomenon in which the deformation of an object increases with time when a constant amount of stress acts on it. In general, the deformation due to creep of a high-strength member is small, and the deformation due to creep is suppressed in a high-strength member. The second member 6 may be made of the same material as the first member 4 , or may be made of a material different from the first member 4 , for example, a material having a higher strength than the first member 4 .

The second member 6 includes a fusion joint 12 and a fastening portion 14 . The fusion connection 12 includes a second mating surface portion 16 to the weld solidification 8 . The second joint surface 16 is arranged on a ring, such as on a circumference, and the end of the first member 4 is inserted inside the second joint surface 16 . The first joint surface portion 10 of the first member 4 is arranged on the extension of the second member 6 having a plate-like or substantially plate-like shape. The fastening portion 14 includes fastening holes 18, for example, and can be fastened to other members by fastening members such as bolts or screws. The second member 6 has a strength higher than, for example, the extent to which loosening of the fastening member can be suppressed, and suppresses loosening of the fastening member.

The weld solidified portion 8 is arranged between the first joint surface portion 10 of the first member 4 and the second joint surface portion 16 of the second member 6, and is located between the first joint surface portion 10 and the second joint surface portion 16. to form a butt joint. The weld-solidified portion 8 is formed by solidifying the first member 4 and the second member 6 (hereinafter referred to as "

members

4 and 6") melted during welding, and is a mixed member of the

members

4 and 6. The weld solidification 8 has, for example, a semi-elliptical or approximately semi-elliptical cross-sectional shape. The weld solidification 8 includes a first solidification 20 and a second solidification 22 . The weld solidified portion 8 has, for example, an annular shape on the exposed surface, as shown in FIG. 1A.

The first solidified portion 20 is arranged outside the weld solidified portion 8, that is, around the weld. The first solidified portion 20 contacts and joins the first joint surface portion 10 and the second joint surface portion 16 to connect the first member 4 to the second member 6 . For example, the first solidified portion 20 is formed by cooling the

members

4 and 6 melted by the first heating such as the first laser irradiation. Cooling of the

members

4 and 6 may be, for example, natural cooling or mild forced cooling.

The second solidified portion 22 is arranged inside the weld solidified portion 8, that is, in the vicinity of the weld center P and the weld center P of the weld. The weld center P is the elliptical center of the weld solidified portion 8 having a semi-elliptical or nearly semi-elliptical cross-sectional shape and coincides or substantially coincides with the heating point of the weld. For example, a part of the

members

4 and 6 cooled after melting is re-melted and re-cooled by second heating such as second laser irradiation to form the second solidified portion 22 . Re-cooling after the second heating may be, for example, natural cooling or mild forced cooling.

The weld solidified portion 8 has residual stress. Residual stress is stress that remains in an object after the object has been subjected to an external force, even if the external force is removed. For example, residual stress is generated when an object heated in heat treatment is cooled. Further, in the heat treatment of dissimilar materials, if the dissimilar materials are mixed unevenly, the composition of the material becomes uneven and residual stress is generated.

The heated welded part is cooled from the periphery of the welded part, and finally the central part of the welded part is solidified. Therefore, in general welding, the residual stress (tensile stress) is high at the central portion of the welded portion. In addition, the larger the amount of heat applied during welding and the larger the volume of the member to be melted, the higher the residual stress. However, in the welded structure 2, the second amount of heat applied to the

members

4, 6 in the second heating is suppressed, and the weld center P and the residual stress in the vicinity of the weld center P are suppressed. When the second member 6 is made of a material different from that of the first member 4, the remelting of the

members

4 and 6 promotes mixing of the

members

4 and 6 and can suppress residual stress due to non-uniformity of materials. . That is, even if the second member 6 and the first member 4 are made of different materials, it is possible to suppress residual stress and maintain a stable connection structure.

The cross-sectional width W2 of the second solidified portion 22 is, for example, 10% or more and 70% or less of the cross-sectional width W1 of the weld solidified portion 8 . Assuming that the second solidified portion 22 is substantially similar to the solidified weld portion 8, if the width W2 is 70% or less of the width W1, the cross-sectional area of the second solidified portion 22 is equal to the cross-sectional area of the solidified weld portion 8 as a whole. is suppressed to less than half of The second heat amount is 50% or less of the first heat amount applied to the

members

4 and 6 by the first heating from the area ratio. The second heat quantity is smaller than the first heat quantity, and the residual stress in the second solidified portion 22 is suppressed. The residual stress at the weld center P of the weld solidified portion 8 and its vicinity can be suppressed more than the residual stress at the weld center P and its vicinity of the weld solidified portion 8 consisting only of the first solidified portion 20 .

When the width W2 is, for example, 10% or more of the width W1, the second solidified portion 22 is sufficiently arranged on the surface near the central portion where residual stress is high. That is, the second solidified portion 22 can make it difficult for the central portion of the exposed surface where cracks are likely to occur to crack. Assuming that the second solidified portion 22 is substantially similar to the solidified weld portion 8, if the width W2 is 10% or more of the width W1, the cross-sectional area of the second solidified portion 22 is equal to the cross-sectional area of the entire solidified weld portion 8. 9% or more of The second amount of heat is 9% or more of the first amount of heat from the area ratio.

The welding center P is arranged, for example, on the first member 4 side with respect to the abutment surface S of the

members

4 and 6 . The butting surface S is a surface formed by butting the

members

4 and 6 before welding. Welding in which the welding center P is arranged on the side of the first member 4 is performed by irradiating the second member 6 with a higher strength with a laser when the second member 6 has a higher strength than the first member 4. The

members

4 and 6 can be welded with a smaller amount of heat than in the case of welding, so residual stress can be suppressed. For welding in which the weld center P is arranged on the side of the first member 4, if the second member 6 has a lower strength than the first member 4, the second member 6 having a lower strength is irradiated with a laser. The difference in the amount of melting between the

members

4 and 6 can be made smaller than in the case of doing so.

The weld central portion P may overlap the abutment surface S, or may be arranged on the second member 6 side with respect to the abutment surface S. Welding in which the weld center P overlaps the abutment surface S can reduce the difference in the amount of fusion between the

members

4 and 6 .

Fig. 3 shows an example of the welding method. The inverted triangle symbols shown in B and D of FIG. 3 represent the irradiation of the laser beam, and the arrows shown in C of FIG. It indicates that a tensile stress exists in the weld solidified portion 8 centering on the central portion. The welding method shown in FIG. 3 is an example, and the technology of the present disclosure is not limited to such a method.

The second member 6 before welding includes, for example, a circular through hole slightly larger than the end of the first member 4 before welding. The second member 6 may have a plurality of circular through holes. As the number of through-holes increases, a high degree of accuracy is required in arranging the ends of the first member 4 and the through-holes. However, since the through-hole has a diameter about 0.1 to 0.5 mm larger than that of the end of the first member 4, a gap of about 0.1 to 0.5 mm is generated. , the end of the member 4 and the through hole can be arranged. As shown in FIG. 3A, the end of the first member 4 is inserted into, for example, a through hole of the second member 6 so that the first member 4 is adjacent to the second member 6 .

As shown in FIG. 3B, adjacent parts 32 of the mutually

adjacent members

4 and 6 are melted by first heating such as first laser irradiation to form melted parts 34 . In FIG. 3B, the center of the first heating is arranged on the side of the first member 4 with respect to the abutment surface S of the

members

4 and 6 . Therefore, even if there is a gap of about 0.1 to 0.5 mm between the

members

4 and 6, stable connection can be achieved. However, the center of the first heating may overlap the abutting surface S, or may be arranged on the second member 6 side with respect to the abutting surface S.

The first heating moves relative to the

members

4 and 6, for example, on a circumference, and melts the adjacent portion 32, for example, in an annular shape. In the relative movement of the first heating, the laser irradiation device may move, and the

members

4 and 6 may move. Due to the movement of the heating point, the melted portion 34 is naturally cooled, and a solidified portion 36 is formed as shown in FIG. 3C.

As already mentioned, the heated weld is cooled from the periphery of the weld, and finally the central part of the weld is solidified. Therefore, the residual stress in the solidified portion 36 becomes high at the central portion of the solidified portion 36 and is generated starting from the central portion of the solidified portion 36 .

As shown in FIG. 3D, part of the solidified portion 36 is remelted by second heating such as second laser irradiation to form a remelted portion 38 . The second heating is applied, for example, to the center of heating in the first heating, that is, the center of the width of the solidified portion 36 . The second heating may be applied to the first member 4 side or the second member 6 side with respect to the heating center in the first heating. The second heat quantity is controlled to be less than the first heat quantity, and the residual stress of the second solidified portion 22 (E in FIG. 3) formed by the solidification of the remelted portion 38 is reduced to that of the solidified portion before remelting. 36 residual stress. That is, the residual stress can be released by remelting the solidified portion 36 . The second heat amount is adjusted to, for example, 9% or more and 50% or less of the first heat amount, and the width W2 is adjusted to 10% or more and 70% or less of the width W1. The first amount of heat and the second amount of heat are adjusted, for example, by any of the following adjustments (1) to (6).
Adjustment (1): Adjusting the outputs of the first laser and the second laser Adjustment (2): Adjusting the distance from the first laser irradiation device and the second laser irradiation device to the members 4 and 6 (3) : Adjusting the incident angles of the first laser and the second laser with respect to the members 4 and 6 (4): Adjusting the heating time of the first heating and the second heating (5): Adjustment of the relative movement speed of the first heating and the second heating Adjustment (6): Combination of multiple adjustments such as Adjustment (1) to Adjustment (5)

The second heating moves relative to the

members

4 and 6, for example, on the circumference, and remelts the solidified portion 36, for example, in an annular shape. Therefore, the remelt portion 38 is cooled to form a weld solidification 8 including a first solidification 20 and a second solidification 22, as shown in FIG. 3E.

The welded structure 2 is manufactured, for example, by the welding method described above. The manufacturing method of the welded structure is the same as the welding method described above, for example, and the description thereof is omitted.

According to the embodiment, the following functions or effects can be obtained.

(1) Residual stress generated in welds causes cracks in welds. Residual stress is presumed to occur due to, for example, the following factors.
Factor (1): In the laser welding of dissimilar members, the melted members were cooled in a state in which they were not sufficiently mixed, resulting in partial differences in contraction speed.
Factor (2): In order to connect the members firmly, a high-power laser is irradiated to form a large weld with large strain.
Factor (3): Metals that tend to generate residual stress and have high crack susceptibility, such as magnesium-containing alloys, are used.
Factor (4): A weld is formed that has a shape that increases residual stress. A weld with a curve, such as an annular shape, has a higher residual stress than a straight weld.
Factor (5): When a member is surface-treated, the material contained in the surface of the member precipitates during welding, which locally reduces the strength of the member.

Due to the required performance or specifications, it may be difficult to eliminate factors (1) to (5) above. The welded structure 2 can suppress cracking even if factors (1) to (5) exist, and can suppress cracking even when welding members selected for required performance or specifications.

The welded structure 2 includes a second solidification 22 formed by a second heat quantity less than the first heat quantity, the second solidification 22 having a cross-sectional area smaller than that of the weld solidification 8 . It has a small residual stress. Formation of the second solidified portion 22 can release, cancel, or alleviate the residual stress. Therefore, a welded structure 2 that is less likely to crack can be obtained.

(2) Since the welded structure 2 is hard to break, it is possible to expand the degree of freedom in combining members.

(3) Since the welded structure 2 is less likely to crack, it is possible to select materials to be used by emphasizing performance or specifications such as electrical characteristics, strength, hardness, and durability rather than weldability. That is, the performance or specifications of the welded structure 2 can be improved.

FIG. 4 shows an example of an electronic component according to the embodiment. FIG. 5 shows an example of an end busbar of an electronic component. The end busbar 64 is, for example, line-symmetrical with respect to the line L shown in FIG. 5A, and FIG. 5A shows the end busbar partially omitted. The configurations shown in FIGS. 4 and 5 are examples, and the technology of the present disclosure is not limited to such configurations. 4 and 5, the same parts as in FIG. 1 are given the same reference numerals. In this embodiment, the installation side of the first holder 56 is referred to as the upper side, and the installation side of the second holder 58 is referred to as the lower side.

The electronic component 52 is, for example, an electronic component module such as a power storage device module, and includes a plurality of power storage devices 54, a first holder 56, a second holder 58, a plurality of holder connection members 60, a connecting bus bar 62, an end portion Includes bus bar 64 and weld solidification 8 .

The plurality of power storage devices 54 are, for example, 18 power storage devices 54, and are arranged so that 3 rows of 6 power storage devices 54 arranged in a straight line are formed. That is, the plurality of power storage devices 54 are arranged in 6 rows and 3 columns. Electricity storage device 54 has an electricity storage function, and is, for example, an electrolytic capacitor or an electric double layer capacitor. Electricity storage device 54 includes, for example, a cylindrical body portion 66 and two electrode terminals 68 projecting from one end surface of body portion 66 .

The electrode terminal 68 is an example of the first member, and is, for example, a metal member made of pure aluminum (alloy number: 1070), and is excellent in workability, corrosion resistance, weldability, and the like. The electrode terminal 68 having excellent corrosion resistance suppresses chemical reaction with the electrolyte, and suppresses the influence of the chemical change of the electrode terminal 68 and the electrolyte on the electrical characteristics. In other words, pure aluminum is a suitable material for the electrode terminals 68 . The alloy number is, for example, the alloy number indicated in Japanese Industrial Standard JIS H4000:2014 "Aluminum and aluminum alloy plates and strips".

The first holder 56 is arranged on the electricity storage device 54 . The first holder 56 is a resin member containing, for example, thermoplastic resin, and has terminal holes (not shown) at positions corresponding to the plurality of arranged electrode terminals 68 . An electrode terminal 68 passes through the terminal hole, and the end of the electrode terminal 68 protrudes from the upper surface of the first holder 56 .

The second holder 58 is arranged below the power storage device 54 . A lower portion of the electricity storage device 54 is fitted into a second holder 58, thereby restricting the movement of the electricity storage device 54. As shown in FIG. The second holder 58 is a resin member containing thermoplastic resin, for example.

The holder connection member 60 is connected to the first holder 56 and the second holder 58, and maintains the separation distance between the first holder 56 and the second holder 58 at a set distance. The first holder 56, the second holder 58, and the holder connecting members 60 at both ends form a frame, and the electrical storage device 54 is arranged in this frame. A central holder connection member 60 maintains a set distance between the first holder 56 and the second holder 58 at the middle of the frame. Holder connection member 60 is a resin member containing, for example, thermoplastic resin.

The connection bus bar 62 is an example of an electrical connection member, has an elongated plate shape, for example, and is arranged on the first holder 56 so as to traverse the three columns of the electricity storage devices 54 . The connecting busbars 62 are welded, for example, to adjacent electrode terminals 68 in each row to electrically connect adjacent power storage devices 54 in each row. The connecting busbars 62 also connect the welded electrode terminals 68 to the welded electrode terminals 68 in the other rows to electrically connect, for example, six electrical storage devices 54 . The connection bus bar 62 is a member similar to the electrode terminal 68, for example.

The end bus bar 64 is an example of a second member, and is an electrical connection member capable of electrically connecting the electrode terminals 68 to other members such as loads. The end busbar 64 has, for example, an elongated plate shape or an elongated substantially plate shape, and is arranged on the first holder 56 so as to traverse the three columns of the electricity storage devices 54 . End busbars 64 are welded to end electrode terminals 68 in each row. End busbars 64 also connect welded electrode terminals 68 to welded electrode terminals 68 in other rows to electrically connect, for example, three electrical storage devices 54 .

The end busbar 64 is a metal member made of, for example, an aluminum-magnesium alloy (alloy number: 5052). An aluminum-magnesium alloy (alloy number: 5052) has excellent corrosion resistance and workability, has high strength and hardness, and suppresses deformation due to creep. An aluminum-magnesium alloy (alloy number: 5052) has good distribution and is excellent in terms of cost. When the end bus bar 64 is fastened to another member with a fastening member such as a bolt or screw, the high-strength end bus bar 64 can suppress loosening of the fastening member.

The end busbar 64 includes three fusion connections 12 and fastening portions 70 . The fusion joint 12 includes a second mating surface portion 16 as described in the embodiment. The second joint surface portion 16 is arranged on a ring, such as on a circumference, and the ends of the electrode terminals 68 are inserted inside the second joint surface portion 16 . The first joint surface portion 10 of the electrode terminal 68 is arranged on the extension of the end bus bar 64 having a plate shape or a substantially plate shape. The weld solidified portion 8 is arranged between the first joint surface portion 10 of the electrode terminal 68 and the second joint surface portion 16 of the end bus bar 64, and is joined to the first joint surface portion 10 and the second joint surface portion 16. , forming a butt joint. The solidified weld portion 8 is the same as the solidified weld portion 8 described in the embodiment, and the description thereof will be omitted. Electrode terminal 68 , end busbar 64 and weld solidification 8 form welded structure 72 , and electronic component 52 includes welded structure 72 .

The fastening portion 70 includes multiple fastening holes 18 and multiple fixing holes 74 . The fastening holes 18 are, for example, five fastening holes 18, and are used for fastening the fastening member to another member. The fixing holes 74 are, for example, two fixing holes 74 and are arranged outside the fastening hole 18 . The fixing holes 74 are used for fixing the end busbars 64 to the first holder 56 . For example, before the end busbars 64 are welded to the electrode terminals 68, the end busbars 64 are fixed to the first holder 56 by fixing holes 74 and fasteners 76 for positioning. When the end bus bar 64 is fixed to the first holder 56 by the fixing hole 74 and the fixture 76 after welding, stress may be applied to the solidified weld portion 8 due to slight deformation of the end bus bar 64 during fixation. be. Fixing the end busbars 64 before welding can remove the possibility of pressurizing the weld solidification 8 during fixing.

The end busbars 64 may include other holes, steps, etc., depending on the purpose, as shown in FIG.

The electronic component 52 may include additional circuits, such as a balance circuit, a temperature detection circuit, and a voltage detection circuit, which are not shown. The additional circuitry is connected to, for example, connection busbars 62 or end busbars 64 . A butt joint with a solidified weld 8 may be used to connect the additional circuit to the bus bar.

The manufacturing process of the electronic component 52 is an example of a manufacturing method and includes, for example, an assembly process and a welding process.

In the assembly process, the power storage device 54, the first holder 56, the second holder 58, the holder connection member 60, the connecting bus bar 62, the end bus bar 64 and the fixture 76 are combined to form a holder as shown in FIG. module.

In the welding process, the end busbars 64 are welded to the electrode terminals 68 by, for example, the welding method described in the embodiment. The connecting bus bar 62 is welded to the electrode terminal 68 . In order to form weld-solidified portion 8 described above, connection bus bar 62 may be welded to electrode terminal 68 by, for example, the welding method described in the embodiment. Description of the welding method described in the embodiment is omitted.

According to the electronic component according to the embodiment, the following action or effect can be obtained.

(1) The action or effect described in the embodiment can be obtained.

(2) Even if the end bus bar 64 having high strength and hardness is welded to the electrode terminal 68, cracking of the solidified weld portion 8 can be suppressed.

(3) By suppressing cracking, it is possible to suppress an increase in electrical resistance and heat generation during energization.

(4) The electrical stability of the electronic component 52 can be enhanced.

(5) The end busbars 64 having high strength and hardness can suppress loosening of tightening with other members. In other words, the thickness of the end bus bar 64 is maintained in a high-temperature environment or over time, so that the axial force of the fastening member is maintained and loosening of the fastening member is suppressed. Therefore, an increase in electrical resistance is suppressed.

The features and modifications of the embodiments or examples are listed below.

(1) In the above embodiments and examples, the solidified weld portion 8 has an annular shape on the exposed surface. However, the shape of the weld-solidified portion 8 is not limited to an annular shape. For example, the second member 6 or the end bus bar 64 has an arc-shaped recess at the end, and this recess is abutted against the end side surface of the first member 4 or the electrode terminal 68 to form an arc-shaped welding solidification. A portion 8 may be formed. The upper portion of the first member 4 or the electrode terminal 68 may have a shape other than a circular shape, and the solidified weld portion 8 may have a shape corresponding to the shape of the first member 4 or the electrode terminal 68 .

(2) The second member 6 includes the fastening portion 14 in the above embodiment, and the end bus bar 64 includes the fastening portion 70 in the above embodiment. However, the second member 6 may not include the fastening portion 14 and the end busbar 64 may not include the fastening portion 70 . The material of the second member 6 or end busbars 64 may be constrained for reasons other than loose fastening, such as stiffness or scratch resistance.

(3) In the above embodiment, the fastening portion 14 of the second member 6 includes the fastening hole 18 . However, as shown in FIG. 6, the fastening portion 14 may include a fastening member 118 such as a male screw, and be fastened to another member by the fastening member 118 . In the above example, the fastening portion 70 of the end bus bar 64 may include the fastening member 118 and may be fastened to another member by the fastening member 118, as in the embodiment.

(4) In the welding methods of the above embodiments and examples, the solidified portion 36 is remelted to form the second solidified portion 22 . The welding method is not limited to the welding methods of the embodiments and examples. For example, as shown in FIG. 7C, during cooling of melt zone 34, a second heating may reheat a portion of melt zone 34 to form reheat zone 138, FIG. D, the reheat zone 138 may solidify to form a second solidified zone 22 . Cooling may be, for example, natural cooling or mild forced cooling. Partial reheating of the melted portion 34 can slow down the cooling rate of the other portion of the melted portion 34 and suppress residual stress in the first solidified portion 20 .

(5) In the above embodiment, the electrode terminal 68 is a metal member made of pure aluminum (alloy number: 1070), and the end bus bar 64 is a metal member made of an aluminum-magnesium alloy (alloy number: 5052). . However, the electrode terminal 68 is not limited to pure aluminum (alloy number: 1070), and may be a metal member made of other pure aluminum having a purity of 99% or more, for example. The end busbars 64 need only be strong enough to suppress the looseness of the fastening member. For example, the end busbar 64 is made of a metal made of an aluminum alloy that can suppress loosening of the fastening, selected from aluminum alloys of the 2000 series to the 7000 series. It may be a member.

(6) In the above embodiment, the electronic component 52 includes 18 power storage devices 54 . However, the number of power storage devices 54 may be less than 18 or may be more than 18. Further, the electronic component 52 is not limited to an electricity storage device module including at least one electricity storage device 54, and may be another electronic component such as a balance circuit.

As described above, the most preferable embodiment and the like of the present disclosure have been described. The present disclosure is not limited to the above description, and various modifications and changes can be made by those skilled in the art based on the gist of the invention described in the claims or disclosed in the specification. It goes without saying that such variations and modifications are included within the scope of the present disclosure.

The technique of the present disclosure is useful because it can be used not only for welding electronic components such as electrical storage device modules and circuits, but also for welding various members.

2, 72 welded structure 4 first member 6 second member 8 solidified welded portion 10 first joint surface portion 12 welded

joint portion

14 , 70 fastening portion 16 second joint surface portion 18 fastening hole 20 first solidified portion 22 Second solidified portion 32 Adjacent portion 34 Melted portion 36 Solidified portion 38 Re-melted portion 52 Electronic component 54 Electricity storage device 56 First holder 58 Second holder 60 Holder connection member 62 Connection bus bar 64 End bus bar 66 Body portion 68 Electrode Terminal 74 Fixing hole 76 Fixing tool 118 Fastening member 138 Reheating unit

Claims

a first member having a first joint surface;
a second member having a second joint surface;
a welded solidified portion formed by welding at the joint surface portion of the first member and the second member that are butted against each other;
with
The welded structure, wherein the weld solidified portion includes a first solidified portion arranged outside and a second solidified portion arranged inside.
The second member has a higher strength than the first member,
2. Welding according to claim 1, wherein the welding central portion of the weld solidified portion is arranged on the first member side with respect to the abutting surfaces of the first member and the second member. structure.
The welded structure according to claim 1 or claim 2, wherein the second member further includes a fastening portion that can be fastened with another member.
The width of the cross section of the second solidified portion is 10% or more and 70% or less of the width of the cross section of the weld solidified portion, according to any one of claims 1 to 3. Welded construction.
The welded structure according to any one of claims 1 to 4, wherein the weld solidified portion has an annular shape.
An electronic component module having the welded structure according to any one of claims 1 to 5.
a step of melting the adjacent portions of the first member and the second member adjacent to each other by the first heating to form a melted portion, and cooling the melted portion;
The second heating remelts or reheats a portion of the melted portion to form a weld solidified portion including an outer first solidified portion and an inner second solidified portion. A welding method comprising:
The second member has a higher strength than the first member,
8. The welding method according to claim 7, wherein the first heating is applied to abutting surfaces of the first member and the second member on the side of the first member.
The welding method according to claim 7 or 8, further comprising the step of forming a fastening portion that can be fastened with another member on the second member.
10. The heat quantity applied by the second heating is 9% or more and 50% or less of the heat quantity applied by the first heating. Welding method.
the first heating and the second heating are applied circumferentially;
The welding method according to any one of claims 7 to 10, wherein the weld solidified portion has an annular shape.
the first member is a terminal of an electronic component or a conductive member connectable to the electronic component;
The welding method according to any one of claims 7 to 11, wherein the second member is an electrical connection member capable of electrically connecting the first member to another member. .