JP2015163410A - Welding method, welding inspection method, and sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method which can form a weld part having a favorable weld-in depth while suppressing the generation of sputtering.SOLUTION: This method welds boundary faces (12, 22) at an L-shaped corner portion (5) which is formed by making an end face (22) of a first metal plate (2, 202) abut on an end part (16) at a surface (12) side of a second metal plate (1, 201). Firstly, an energy line having intensity capable of forming a keyhole is radiated to the vicinity of the boundary face (12) at the second metal plate (1, 201) from the first metal plate (2, 202) side, and the keyhole is formed at the second metal plate (1, 201) (S1). Furthermore, by continuously radiating the energy line, the boundary faces (12, 22) and an angular part (15) at the corner portion (5) are fused (S2) so that a fused part (40) which is shallower than a thickness of the first metal plate (2, 202) is formed.

Description

  The present invention relates to a welding method, a welding inspection method, and a sealed battery, and more particularly, to a welding method, a welding inspection method, and a sealed battery that are welded and joined by energy rays.

  2. Description of the Related Art A welding method is used in which energy beams are irradiated to materials to be welded to weld the materials to be welded together.

  For example, as shown in FIG. 15, there is laser welding in which laser as an energy ray is irradiated to the battery housing portion 80 and the lid 81 for welding. The battery housing part 80 and the lid 81 are made of aluminum or an aluminum alloy. As shown in the partially enlarged sectional view of FIG. 15, the end surface 83 of the lid 81 is abutted against the end portion 84 on the inner wall surface side of the battery housing portion 80. When the laser is applied to the boundary between the end surface 83 and the end portion 84 on the inner wall surface side or in the vicinity thereof, the melted portion 82 is formed. When the laser irradiation is stopped and the melted portion 82 is solidified, a welded portion is formed. It is preferable that the depth of the melted portion 82 (welded portion) is shallower than the thickness of the lid 81 and is in a predetermined range because the battery housing portion 80 and the lid 81 can be joined with high joint strength.

  As an example of the laser welding described above, as shown in the partially enlarged sectional view of FIG. 15, heat conduction for welding the battery housing portion 80 and the lid 81 using a laser having an energy density at which the melting portion 82 does not boil. There is welding. The upper surface of the melting part 82 is a flat surface or a slightly concave concave surface. When the laser is continuously irradiated to the melting portion 82, most of the laser is reflected by the upper surface of the melting portion 82, and the remainder is absorbed by the melting portion 82. In heat conduction welding, the depth of the melted part 82 becomes too shallow, and a preferable depth may not be obtained.

  Further, as another example of the laser welding described above, as shown in FIG. 16, the battery is accommodated by using a laser at a level where the melting portion 82 boils at a higher energy density than the laser used in the above-described heat conduction welding. There is keyhole welding for welding the portion 80 and the lid 81. In such keyhole welding, first, the melted portion 82 is formed by laser irradiation, and then the keyhole 85 is formed inside the melted portion 82. When the laser is further irradiated to the keyhole 85, the laser repeatedly reflects a plurality of times in the keyhole 85, most of the laser is absorbed by the melting portion 82, and the remainder is emitted to the outside of the melting portion 82. In keyhole welding, a deep melting portion 82 is formed as compared with heat conduction welding, but the variation in depth of the melting portion 82 is large. For example, depending on the portion of the melted portion, the depth of penetration may be too shallow, and the bonding strength between the battery housing portion 80 and the lid 81 may be insufficient. On the other hand, the penetration depth may be too deep and the formed melted part 82 may melt and penetrate.

  Therefore, in the welding method disclosed in Patent Document 1, the above-described heat conduction welding and keyhole welding are alternately performed using a continuous wave laser welding apparatus, and the battery housing portion and its lid are welded. According to this, welding can be performed while forming a melted portion having a preferable penetration depth.

JP 2009-245758 A

  By the way, the heat input to the material to be welded differs greatly between heat conduction welding and keyhole welding. Therefore, in the welding method disclosed in Patent Document 1, the amount of heat input to the material to be welded changes abruptly, causing a thermal shock, and spatter may be scattered. Further, the spatter scattering may cause welding defects.

  Therefore, the present invention has been made against the background described above, and it is an object of the present invention to provide a welding method capable of forming a melted portion having a preferable penetration depth while suppressing the occurrence of spatter.

The welding method according to the present invention includes:
The first metal plate and the second metal at the corner portion having an L-shaped cross section formed by abutting the end surface of the first metal plate and the end portion on the surface (for example, inner wall surface) side of the second metal plate. In the welding method in which the boundary surface with the plate is welded and joined with energy rays,
The energy beam having an intensity capable of forming a keyhole is irradiated from the first metal plate side toward the vicinity of the boundary surface of the second metal plate, and the keyhole is applied to the second metal plate. Forming a step;
By continuously irradiating the energy beam, the boundary surface, and the corner of the second metal plate at the corner portion, so as to form a melted portion shallower than the thickness of the first metal plate, Melting the step.

  According to such a configuration, welding can be performed by forming a weld portion having a preferable penetration depth while suppressing generation of spatter.

  The inclination angle formed by the optical axis of the energy beam and the boundary surface may be not less than 0.5 ° and not more than 15 °. Further, the depth of the melting part may be 25 to 75% with respect to the thickness of the first metal plate. The thickness of the first metal plate may be 120% or more with respect to the thickness of the second metal plate.

  According to such a structure, the welding part which has a preferable penetration depth can be formed more reliably and welding can be performed.

  Detecting welding light emitted from the molten part or the vicinity of the molten part, converting the welding light into a voltage signal, calculating an average value of the voltage for each welding section from the voltage signal, the average value of the voltage, Welding may be performed so that the average value of the voltage calculated from the welding light at the time of heat conduction welding detected in advance and the average value of the voltage calculated from the welding light at the time of keyhole welding are included.

  According to such a configuration, it is possible to perform in-line determination as to the quality of welding while performing welding.

  Further, in the above welding method, the second metal plate is a wall in the battery housing portion, the first metal plate is a lid, and the battery housing portion and the lid are connected by the above welding method. A battery container that is welded and sealed may be manufactured. According to such a structure, the battery container which joined the battery accommodating part and the lid | cover with high joining strength can be manufactured.

  On the other hand, the sealed battery according to the present invention may include the battery container manufactured by the above-described welding method. According to such a configuration, a battery container having high hermeticity can be obtained.

On the other hand, the welding inspection method according to the present invention is the above-described welding method, wherein welding light emitted from the melted part or the vicinity of the melted part is detected, the welding light is converted into a voltage signal, and the welding section is converted from the voltage signal. Calculate the average value of each voltage,
The average value of the voltage is determined based on the average value of the voltage calculated from the welding light detected at the time of heat conduction welding detected in advance and the average value of the voltage calculated from the welding light at the time of keyhole welding. To do.

  According to such a structure, the quality of welding can be determined in a short time.

  ADVANTAGE OF THE INVENTION According to this invention, the welding method which can form the fusion | melting part which has preferable penetration depth, suppressing generation | occurrence | production of a sputter | spatter can be provided.

It is a disassembled perspective view of an example of a welding processed product. It is a perspective view of an example of a welding processed product. It is a fragmentary sectional view of an example of a welding processed product. 1 is a schematic diagram of a welding method according to a first embodiment. 1 is a schematic diagram of a welding method according to a first embodiment. 1 is a schematic diagram of a welding method according to a first embodiment. 1 is a schematic diagram of a welding method according to a first embodiment. Penetration depth with respect to energy density. It is a cross-sectional structure | tissue photograph of a welding part. FIG. 6 is a schematic diagram of a welding method according to a second embodiment. 3 is a flowchart of a welding method according to a second embodiment. This is a feature of each welding method. This is the average voltage for the welding section. It is an evaluation result of an Example and a comparative example. It is a schematic diagram of the welding method of a prior art. It is a schematic diagram of the welding method of a prior art.

(Embodiment 1)
An example of a welded product obtained using the welding method according to the first embodiment will be described with reference to FIGS. An example of the welded product is a battery.

  As shown in FIG. 1, the battery 10 includes a battery housing portion 1, a lid 2, and a battery body 3. The battery housing part 1 has a rectangular opening 11 at the top. The edge of the opening 11 is an end 16 formed by the thickness of the plate. The battery housing part 1 has a volume that can accommodate at least the battery body 3. The lid 2 is a plate-like body having a shape that can close the opening 11. The battery housing part 1 and the lid 2 are made of a metal material. Examples of the metal material include aluminum or an aluminum alloy. The battery housing portion 1 and the lid 2 constitute a battery container that seals the battery body 3. The battery 10 is connected to a predetermined terminal or the like to the battery body 3 and supplies a current.

  As shown in FIG. 2, the battery housing 1 and the lid 2 are welded by a welding method described later in a state where the battery main body 3 is housed in the battery housing 1 and the opening 11 is closed with the lid 2. Is done. As shown in FIG. 3, the welded portion 4 is formed between the battery housing portion 1 and the lid 2. The welded portion 4 is formed by solidifying a molten portion 40 (described later) by a welding method described later. The battery housing part 1 and the lid 2 are joined by a welded part 4. Here, the battery housing portion 1 and the lid 2 form a corner portion 5 having an L-shaped cross section. The opening 11 is sealed with the lid 2. The battery 10 is a sealed battery having high hermeticity. Here, the depth D4 of the welded portion 4 is preferably 25 to 75% of the thickness T2 of the lid 2, and more preferably 40 to 60%. When the depth D4 of the welded part 4 is within such a range, the battery housing part 1 and the lid 2 can be joined with high joining strength. Moreover, it is preferable that the thickness T2 of the lid 2 is 120% or more of the thickness T1 of the battery housing portion 1 because the battery housing portion 1 and the lid 2 can be joined with high joint strength. When the battery housing part 1 and the lid 2 are joined with high joint strength, they function as a battery container having high sealing properties.

  By the way, a battery mounted in an electric vehicle, a hybrid car, or the like is required to have high hermeticity. On the other hand, the battery 10 includes a battery housing portion 1 and a lid 2 that are bonded to each other with high bonding strength, and has high sealing performance. Therefore, the battery 10 is very suitable as a battery mounted on an electric vehicle, a hybrid car, or the like.

(Welding method)
Next, the welding method according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 4, first, prior to welding, the lid 2 is disposed so as to close the opening 11 of the battery housing portion 1. Here, the end portion 16 of the battery housing portion 1 includes an inner wall surface 12, an outer wall surface 13, an upper end surface 14, and a corner portion 15 formed by intersecting the outer wall surface 13 and the upper end surface 14. And the end surface 22 of the lid | cover 2 is faced | matched with the edge part 16 by the side of the inner wall surface 12 of the battery accommodating part 1, and the cross-sectional L-shaped corner part 5 is formed. Here, the boundary surface between the battery housing portion 1 and the lid 2 is a mating surface between the end surface 22 of the lid 2 and the inner wall surface 12 of the battery housing portion 1.

Laser irradiation is performed from the lid 2 side toward the battery housing portion 1 (keyhole forming step S1). The location where the laser is irradiated is, for example, the inner wall surface 12 side of the upper end surface 14 of the battery housing portion 1. Specifically, the laser beam is irradiated on the upper end surface 14 closer to the inner wall surface 12 than the outer wall surface 13. In addition, since the laser has a predetermined width, if the optical axis A1 of the laser is positioned at a position closer to the inner wall surface 12 than the outer wall surface 13 on the upper end surface 14, the laser is directed to the end surface 22 side on the upper surface of the lid 2. It may also take. Further, the laser is irradiated so that the optical axis A1 of the laser is located on the upper surface of the lid 2 at a position slightly larger than the thickness T1 of the battery housing portion 1 from the outer wall surface 13 to the lid 2 side. May be. For example, when the thickness T1 (see FIG. 3) of the battery housing portion 1 is 0.40 mm, the optical axis A1 of the laser is 0.45 mm from the outer wall surface 13 of the battery housing portion 1 to the lid 2 side on the top surface of the lid 2. You may irradiate a laser so that it may be located in a distant place. The irradiated laser has an energy density that forms a keyhole in the lid 2 and the battery housing part 1 which are members to be welded. That is, the energy density of the laser is in the keyhole region. Specifically, the keyhole region changes depending on the material of the lid 2 and the battery housing part 1. When the lid 2 and the battery housing part 1 are made of aluminum or an aluminum alloy, an example of the keyhole region is about 18 to 24 kW / mm ² . Further, an angle formed between a virtual straight line L1 parallel to the inner wall surface 12 and the end surface 22 and the optical axis A1 of the laser is defined as an inclination angle θ. The inclination angle θ is preferably 0.5 ° or more and 15 ° or less, and more preferably 0.5 ° or more and 10 ° or less.

  As shown in FIG. 5, when the laser irradiation is continued (continuous irradiation step S2), the melting part 40 is formed. 5 to 7, the melting part 40 is drawn using hatching representing a liquid, but the melting part 40 is a melted part. If laser irradiation is continued, as shown in FIG. 6, the opening of the keyhole 41 continues to expand, and the corner 15 of the battery housing part 1 melts. Specifically, at least a part of the end surface 22 of the lid 2, the inner wall surface 12 of the battery housing portion 1, the upper end surface 14 of the battery housing portion 1, and the outer wall surface 13 of the battery housing portion 1 is melted. Here, the laser beam is reflected only once on the concave curved surface of the melting part 40 without being subjected to multiple reflections, and leaves the melting part 40. That is, most of the laser, for example, 80 to 95% is reflected by the melting portion 40 and emitted to the outside of the battery housing portion 1. On the other hand, the remainder is absorbed by the melting part 40.

  Finally, as shown in FIG. 7, after the melting part 40 reaches the depth D <b> 4, laser irradiation is performed along the opening 11 (see FIGS. 1 and 2) of the battery housing part 1. Here, the depth D4 is, for example, 25 to 75% of the thickness T2 of the lid 2. Here, the laser irradiation is stopped. When a predetermined time elapses, the melted portion 40 is solidified to form the welded portion 4 (see FIG. 3).

  As mentioned above, according to the welding method concerning Embodiment 1, since the laser which has the energy density of a predetermined range is continuously irradiated, generation | occurrence | production of a sputter | spatter can be suppressed.

  In addition, according to the welding method according to the first embodiment, the laser is irradiated at a predetermined inclination angle θ, so that a melted portion having a preferred depth is formed and a welded portion having a preferred depth is formed. Can be made.

  In the welding method according to the first embodiment, the opening of the keyhole 41 is more reliably expanded to the outer wall surface 13 of the battery housing part 1 in the continuous irradiation step S2 by setting the inclination angle θ within a predetermined range. Can be made. That is, it is possible to more reliably form a melted portion having a preferred depth and form a welded portion having a preferred depth.

(Prototype experiment)
Next, with reference to FIG. 8 and FIG. 9, a prototype experiment conducted using the welding method according to the first embodiment will be described.

  The experimental method of this prototype experiment will be described. A prototype experiment was performed in which a battery housing portion and a lid of a predetermined size were welded. The welded battery housing part had a thickness T1 (see FIG. 3) of 0.4 mm and a lid thickness T2 (see FIG. 3) of 1.4 mm. The battery housing portion is made of aluminum or an aluminum alloy. The lid is made of the same type of material as the battery housing.

Here, when irradiating laser to aluminum or aluminum alloy as a material to be welded, it is known that the heat conduction region is about 14 to 16 kW / mm ² , and the keyhole region is about 18 to 24 kW / mm ² . In an embodiment, the energy density of the laser is within the keyhole region. In the example, the laser tilt angle θ was set to 5 °. In the comparative example, the energy density of the laser is in the range from the heat conduction region to the keyhole region. In the comparative example, the laser inclination angle θ was set to 0 °.

  The cross section of the welded part made as a prototype was observed. The depth of the weld, that is, the penetration depth was measured. The result is shown in FIG.

  As shown in FIG. 8, the average penetration depth of the examples is about 0.4 to 0.8 mm, about 29 to 57% of the lid thickness T2 (1.4 mm), and a preferable penetration depth. It was possible to form a weld having the same.

  Here, one cross-sectional structure of the example was observed. As shown in FIG. 9, when the battery accommodating part 201 and the lid | cover 202 were welded, the welding part 204 was obtained. In this embodiment, the depth D24 of the welded portion 204 is about 43% of the thickness T22 of the lid 202. Therefore, the battery housing part 201 and the lid 202 have high bonding strength. That is, the battery housing part 201 and the lid 202 function as a highly airtight container. In this embodiment, the welded portion 204 has a shape protruding upward, but this shape does not significantly affect the bonding strength between the battery housing portion and the lid.

Referring to FIG. 8 again, in the heat conduction region (about 14 to 16 kW / mm ² ), the average penetration depth of the comparative example is about 0.2 to 0.3 mm, which is about 14 to about the lid thickness T2. It was as shallow as 21%. In the keyhole region (about 18 to 24 kW / mm ² ), the average penetration depth of the comparative example was as deep as about 1.0 to 1.4 mm. The penetration depth of the comparative example was about 86 to 100% of the lid thickness T2. In addition, when the penetration depth is 1.4 mm, the lid is melted down and penetrated. That is, in this state, the battery housing portion and the lid are not joined and are separated.

  In the welding method according to the first embodiment, a welded material made of aluminum or an aluminum alloy is used, but a welded material made of another metal material such as steel or magnesium alloy may be used. Moreover, it is thought that the metal material which has a big heat conductivity like aluminum or aluminum alloy is especially suitable as a to-be-welded material of the welding method concerning Embodiment 1. FIG.

  In the welding method according to the first embodiment, the laser is used as the energy beam, but an electron beam may be used.

(Embodiment 2)
Next, the welding method according to the second embodiment will be described with reference to FIG.

  In the welding method according to the second embodiment, for example, a welding apparatus 50 shown in FIG. 10 is used. As shown in FIG. 10, the welding apparatus 50 includes a laser oscillator 51, a half mirror 52, a reflection mirror 53, a transmission plate 54, a reflection mirror 55, a light receiving sensor 56, a communication cable 57, and an information processing terminal. 58.

  The laser oscillator 51 is supplied with electric power from a power source (not shown) and oscillates the laser LB. The laser oscillator 51, the half mirror 52, the reflection mirror 53, the transmission plate 54, the reflection mirror 55, and the light receiving sensor 56 are fixed at predetermined positions inside the torch 59, for example. The light receiving sensor 56 is, for example, a photodiode sensor. The communication cable 57 guides a predetermined signal from the light receiving sensor 56 to the information processing terminal 58.

  Information processing terminal 58 includes a filter 581, a welding pass / fail determination unit 582, and a welding control unit 583. The information processing terminal 58 is, for example, a PC (personal computer) or a tablet terminal. The information processing terminal 58 stores, for example, a voltage for each welding section during heat conduction welding (described later), a voltage for each welding section during keyhole welding (described later), and the like. The filter 581 removes noise components from the voltage signal. The filter 581 is, for example, a bypass filter or a low-pass filter. The welding quality determination unit 582 determines quality of welding based on the voltage signal. The welding control unit 583 feedback-controls each component of the welding apparatus 50 based on the quality of welding. Control of each component of the welding apparatus 50 includes, for example, control for changing the output of the laser oscillator 51, the position and posture angle of the reflection mirror 53, and the like.

Here, the path of the laser beam LB and the light WB emitted from the melting part 40 (see FIG. 7) or the vicinity thereof will be described.
First, the laser oscillator 51 irradiates the half mirror 52 with the laser LB. The half mirror 52 reflects at least a part of the laser LB so as to enter the reflection mirror 53. The reflection mirror 53 reflects the laser LB, passes through the transmission plate 54, and enters the battery housing 1 from the lid 2 side. The battery housing part 1 receives the laser LB, and the plasma light WB is emitted from the melting part 40 or the vicinity thereof.

  At least a part of the plasma light WB passes through the transmission plate 54 and enters the reflection mirror 53. The reflection mirror 53 reflects the plasma light WB, passes through the half mirror 52, and further enters the reflection mirror 55. The reflection mirror 55 reflects the plasma light WB and makes it incident on the light receiving sensor 56. The light receiving sensor 56 receives the plasma light WB and converts the intensity of the plasma light WB into a voltage signal.

  Next, a welding method according to the second embodiment will be described with reference to FIGS. Note that the scales of the horizontal axis and the vertical axis of the graph of the voltage with respect to the welding time in FIG. 12 are unified to the same size.

  Prior to the welding method according to the second embodiment, heat conduction welding and keyhole welding are performed in advance using the above-described welding apparatus 50, the voltage for each welding section is measured, and the average value is calculated. You may keep it. In keyhole welding, the energy density of the laser is within the keyhole region. In heat conduction welding, the energy density of the laser is in the range from the heat conduction region to the keyhole region. In keyhole welding and heat conduction welding, the tilt angle θ of the laser was set to 0 °. As shown in FIG. 13, the average value of the voltage for each welding section at the time of heat conduction welding (Comparative Example 2) is lower than the average value of the voltage for each welding section at the time of keyhole welding (Comparative Example 1). . Here, the average value of the voltage for each welding section during keyhole welding is defined as a threshold value A. Further, an average value of the voltage for each welding section at the time of heat conduction welding is defined as a threshold value B. The threshold value A and the threshold value B are stored in the information processing terminal 58.

  First, the keyhole formation process S1 (refer FIG. 4) is implemented similarly to the welding method concerning Embodiment 1, and the continuous irradiation process S2 (refer FIGS. 5-7) is implemented subsequently. After the melting part 40 is formed in the continuous irradiation step S2 at the latest, plasma light WB by welding is generated from the melting part 40 or the vicinity thereof (light emission step S21).

  Next, the plasma light WB is received and converted into a voltage signal (voltage conversion step S22). Next, the converted voltage signal is processed and converted into data (data processing step S23). As the converted data, for example, as shown in FIG. 12, a waveform signal with respect to the welding time before noise removal is obtained. Note that the welding time in FIG. 12 is almost directly proportional to the welded distance.

  Next, a noise component is removed from the voltage signal using the filter 581 (noise removal step S24). As the voltage signal from which the noise component has been removed, for example, as shown in FIG. 12, a waveform signal with respect to the welding time after noise removal is obtained.

  Next, the data about the voltage signal from which the noise component has been removed is divided into a plurality of welding sections (welding section dividing step S25). Next, an average value of the voltage is calculated for each divided welding section. (Average voltage calculation step S26).

  As shown in FIG. 13, the average value of the calculated voltage is equal to or less than a threshold value A (keyhole welding determination step S27: YES), and the calculated average value of the voltage is equal to or more than a threshold value B (heat conduction welding). Determination step S28: YES), welding is performed by the same welding method as the welding method according to the first embodiment, and the quality of the welding is determined as “good” (good determination step S29).

  When the calculated average voltage exceeds the threshold value A (keyhole welding determination step S27: NO), keyhole welding is performed and the quality of the welding is determined as “bad” (defect determination step S30). .

  Further, when the calculated average voltage is lower than the threshold value B (heat conduction welding determination step S28: NO), heat conduction welding is performed, and the quality of the welding is determined as “bad” (failure determination step S31). . When it is determined that the quality of welding is “bad” (defect determination steps S30 and S31), the operation of each component of the welding apparatus 50 may be feedback controlled so that the determination of quality of welding changes to “good”. .

  As described above, according to the welding method according to the second embodiment, it is determined whether the welding method of the same form as the welding method according to the first embodiment is performed instead of keyhole welding and heat conduction welding while performing welding. Can be determined by time. That is, it is possible to make an inline determination as to whether the welding is good or bad. Furthermore, feedback control is performed on the operation of each component of the welding apparatus 50 based on the determination result, and good welding can be performed more reliably with the same welding method as the welding method according to the first embodiment.

  In the above-described welding method according to the second embodiment, plasma light generated during welding is received, but light generated during welding other than plasma light may be received. Examples of light generated during welding other than plasma light include reflected light and infrared light. Moreover, you may install an optical filter in the middle of the optical path as needed. It is preferable to install an optical filter in this manner because light components having different wavelengths, such as plasma light, reflected light, and infrared light, can be appropriately separated. Further, the order of the keyhole welding determination step S27 and the heat conduction welding determination step S28 may be switched.

(Welding experiment)
Next, a welding experiment was performed using the welding method according to the second embodiment. In Example 1, the welding method according to the second embodiment was used. On the other hand, keyhole welding was performed in Comparative Example 1, and heat conduction welding was performed in Comparative Example 2. Also in the comparative example 1 and the comparative example 2, the same step as the light emission step S21-noise removal step S24 in the welding method concerning Embodiment 2 was implemented, respectively. The waveform signal during welding was measured. Moreover, the cross section of each welding part was observed. The results are shown in FIG.

  As shown in FIG. 12, the welded portion of Example 1 has a preferable penetration depth and high joint strength. Moreover, in Example 1, generation | occurrence | production of the sputter | spatter during welding is suppressed. Therefore, the welded portion of Example 1 is less likely to generate voids and has excellent welding quality stability. In addition, the waveform signal obtained in Example 1 has a high average value and noise.

  On the other hand, compared with the welded part of Example 1, the welded part of Comparative Example 1 has the same penetration depth and sufficiently high joint strength. However, in Comparative Example 1, compared to Example 1, spatter is easily scattered. Therefore, compared with the welded part of Example 1, the welded part of Comparative Example 1 is more likely to generate voids and is less stable in welding quality. In addition, the waveform signal obtained in Comparative Example 1 has a higher average value and a larger noise component compared to Example 1 and the waveform signal.

  On the other hand, the welded part of Comparative Example 2 has the same degree of stability in welding quality as compared with the welded part of Example 1. However, in the welded part of Comparative Example 2, the penetration depth is insufficient and the joint strength is low as compared with the welded part of Example 1. In addition, the waveform signal obtained in Comparative Example 2 has a lower average value and a smaller noise component compared to Example 1 and the waveform signal.

(Evaluation experiment of inspection method)
Next, with reference to FIG. 14, an evaluation experiment of the welding portion inspection method will be described.

  In Example 1, the welded portion was inspected using the welding light determination method. The welding light determination method is light emission step S21-defect determination step S31 among the welding methods according to the second embodiment described above. In Comparative Example 3, the cross section of the welded portion of the welded product by the welding method according to the first and second embodiments was observed and inspected. In Comparative Example 4, the welded part of the welded product by the welding method according to the first and second embodiments was inspected using X-ray CT (Computed Tomography).

  The measurement time, measurement accuracy, and in-line determination were evaluated for Example 1, Comparative Example 3, and Comparative Example 4, and the results are shown in FIG. In FIG. 14, “◯” is described in the measurement accuracy column when the measurement accuracy is good, and “Δ” is described in the measurement accuracy column when the measurement accuracy is average. In addition, “◯” was described as being suitable for inline determination, and “X” was described as being inappropriate for inline determination.

  As shown in FIG. 14, in the above example, the measurement time was 1 sec or less, and the measurement accuracy was good (◯). Therefore, the embodiment is suitable for inline determination (◯).

  On the other hand, in Comparative Example 3, although the measurement accuracy was good (◯), the measurement time was 3 h (3 hours), which was very long compared to the example. Therefore, Comparative Example 3 is unsuitable for inline determination (x).

  In Comparative Example 4, although the measurement accuracy was good (◯), the measurement time was 1 h (1 hour) or less, which was much longer than that of the example. Therefore, Comparative Example 4 is not suitable for inline determination (x).

  Further, the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, in the welding method according to the first embodiment, a battery is obtained as an example of a welded product. However, a container that can accommodate things other than the battery main body may be obtained. Moreover, in the welding method concerning Embodiment 1 and 2, although the battery accommodating part and the lid | cover were welded, you may weld metal plates. Moreover, in the welding method concerning Embodiment 1 and 2, although the weld part was formed, the weld heat affected part may be contained in this weld part.

10 Battery 1,201 Battery compartment
DESCRIPTION OF SYMBOLS 11 Opening part 12 Inner wall surface 13 Outer wall surface 14 Upper end surface 15 Corner | angular part 16 End part 2,202 Lid 22 End surface 3 Battery body 4,204 Welding part 40 Melting part 41 Keyhole 5 Corner part L1 Virtual straight line A1 Optical axis (theta) Inclination angle S1 Keyhole formation process S2 Continuous irradiation process

Claims (8)

A boundary surface between the first metal plate and the second metal plate at a corner portion having an L-shaped cross section formed by abutting the end surface of the first metal plate and the end portion on the surface side of the second metal plate. In the welding method of welding and joining with energy rays,
The energy beam having an intensity capable of forming a keyhole is irradiated from the first metal plate side toward the vicinity of the boundary surface of the second metal plate, and the keyhole is applied to the second metal plate. Forming a step;
By continuously irradiating the energy beam, the boundary surface, and the corner of the second metal plate at the corner portion, so as to form a melted portion shallower than the thickness of the first metal plate, And a step of melting the material.   The welding method according to claim 1, wherein an inclination angle formed by the optical axis of the energy beam and the boundary surface is 0.5 ° or more and 15 ° or less.   The welding method according to claim 1 or 2, wherein a depth of the melted portion is 25 to 75% with respect to a thickness of the first metal plate.   The thickness of the said 1st metal plate is 120% or more with respect to the thickness of the said 2nd metal plate, The welding method as described in any one of Claims 1-3 characterized by the above-mentioned. In the welding method as described in any one of Claims 1-4,
Detecting welding light emitted from the molten part or the vicinity of the molten part, converting the welding light into a voltage signal, calculating an average value of the voltage for each welding section from the voltage signal,
Welding so that the average value of the voltage falls between the average value of the voltage calculated from the welding light at the time of heat conduction welding detected in advance and the average value of the voltage calculated from the welding light at the time of keyhole welding. A welding method characterized by the above. The second metal plate is a wall in the battery housing;
The first metal plate is a lid;
A welding method for manufacturing a sealed battery container by welding the battery housing part and the lid by the welding method according to claim 1.   A sealed battery having the battery container manufactured by the welding method according to claim 6. A welding inspection method for inspecting a welded portion in the welding method according to any one of claims 1 to 4,
Detecting welding light emitted from the molten part or the vicinity of the molten part, converting the welding light into a voltage signal, calculating an average value of the voltage for each welding section from the voltage signal,
The average value of the voltage is determined based on the average value of the voltage calculated from the welding light detected at the time of heat conduction welding detected in advance and the average value of the voltage calculated from the welding light at the time of keyhole welding. Welding inspection method.