JP7348119B2 - Welding method and battery module manufacturing method - Google Patents

Description

The technology disclosed herein relates to a welding method and a battery module manufacturing method.

A welding method is disclosed in Patent Document 1. In the welding method of Patent Document 1, a first member, a second member stacked on the back surface of the first member, and a third member stacked on the front surface of the first member are welded. The first member is made of aluminum-based metal. The second member and the third member are made of a steel-based metal having a melting point higher than that of an aluminum-based metal. The welding method of Patent Document 1 is to weld the first member, the second member, and the third member by passing a current between the pair of electrodes while the first member, the second member, and the third member are arranged between the pair of electrodes. It has a welding process that resistance welds three members. The welding process includes a pressurizing process in which the second member and the third member are pressurized toward the first member by the tip of one of the pair of electrodes and the tip of the other electrode.

Japanese Patent Application Publication No. 7-328774

In the welding method of Patent Document 1, the first member is removed from between the second member and the third member in the pressurizing step of pressurizing the second member and the third member. Therefore, the contact state between the first member, the second member, and the third member may deteriorate. For example, the second member and the third member may come into direct contact without using the first member. In this case, for example, when the first member and the second member are energized, the contact between the first member and the second member may become poor. Therefore, the present specification provides a technique that can maintain a good state of contact between members.

The welding method disclosed in this specification includes a first member, a second member stacked on one side of the first member, and a third member stacked on the other side of the first member. May be welded. The first member may be made of a first metal. The second member may be made of a second metal having a melting point higher than that of the first metal. The third member may be made of a third metal having a melting point higher than the melting point of the first metal or the second metal. The welding method includes applying a current between the pair of electrodes in a state where the first member, the second member, and the third member are arranged between the pair of electrodes, thereby welding the first member and the second member. and the third member may be resistance welded. The welding step may include a pressurizing step of pressurizing the second member and the third member toward the first member by a tip of one electrode and a tip of the other electrode of the pair of electrodes. . In the pressurizing step, the distance between the tip of the one electrode and the tip of the other electrode is maintained longer than the sum of the thickness of the second member and the thickness of the third member. Good too.

According to this configuration, even if the first member melts faster than the second and third members in the welding process, the first member is between the second and third members when the pressurizing process is performed. remain. The first member is not removed from between the second member and the third member. Therefore, it is possible to suppress direct contact between the second member and the third member without interposing the first member. Thereby, the contact state between the first member, the second member, and the third member can be maintained in a good state.

The first member may be an electrode tab of a first battery. The second member may be an electrode tab of a second battery connected to the electrode tab of the first battery.

In a welding method in which the first member is not removed from between the second and third members, it is possible to maintain a good contact state between the first and second members. Therefore, when the first member and the second member are electrode tabs that are connected to each other, the electrical connection state between the electrode tabs can be maintained in a good state.

A surface of the second member opposite to the first member may be supported by a support member.

Since the second member is pressurized in a molten state during the welding process, it is possible that the second member may be deformed and warped during the welding process. However, by supporting the second member by the support member, it is possible to suppress the second member from warping.

The support member may be arranged around an electrode of the pair of electrodes that presses the second member.

The second member becomes particularly hot around the electrode that pressurizes the second member, and therefore becomes easily deformed. However, since the second member is supported by the support member around the electrode that presses the second member, deformation of the second member can be suppressed.

The heat of the first member may be absorbed by a heat absorbing member.

According to this configuration, the timing at which the first member melts in the welding process can be delayed. This allows the timing at which the first member melts to be brought closer to the timing at which the second and third members melt. As a result, the first member, the second member, and the third member can be joined well.

The heat absorbing member may be made of a metal having a higher thermal conductivity than the first metal.

According to this configuration, the heat of the first member can be quickly absorbed.

The first metal may be an aluminum metal. The second metal may be a copper-based metal.

According to this configuration, the above welding method can be applied to aluminum-based metals and copper-based metals that are suitable for electrode tabs of batteries. Since there is a large difference in melting point between aluminum-based metals and copper-based metals, the above welding method is particularly effective.

This specification discloses a method for manufacturing a battery module including a first battery including a first electrode tab and a second battery including a second electrode tab connected to the first electrode tab. This manufacturing method includes the first electrode tab, the second electrode tab stacked on one side of the first electrode tab, and a metal member stacked on the other side of the first electrode tab. It may also include a welding process. The first electrode tab may be made of a first metal. The second electrode tab may be made of a second metal having a melting point higher than that of the first metal. The metal member may be made of a third metal or the second metal having a melting point higher than the melting point of the first metal. In the welding step, the first electrode tab, the second electrode tab, and the metal member are arranged between the pair of electrodes, and by passing a current between the pair of electrodes, the first electrode tab and the metal member are disposed between the first electrode tab, the second electrode tab, and the metal member. The second electrode tab and the metal member may be resistance welded. The welding step may include a pressurizing step of pressurizing the second electrode tab and the metal member toward the first electrode tab by a tip of one electrode and a tip of the other electrode of the pair of electrodes. good. In the pressurizing step, the distance between the tip of the one electrode and the tip of the other electrode is maintained longer than the sum of the thickness of the second electrode tab and the thickness of the metal member. Good too.

According to this configuration, the first electrode tab remains between the second electrode tab and the metal member when the pressurizing step is performed. A portion of the first electrode tab is not removed from between the second electrode tab and the metal member. Thereby, the contact state between the first electrode tab and the second electrode tab can be maintained in a good state. Therefore, the electrical connection state between the first electrode tab and the second electrode tab can be maintained in a good state.

The second electrode tab may include a metal member.

According to this configuration, the first electrode tab can be sandwiched between the second electrode tabs. Therefore, the electrical connection state between the first electrode tab and the second electrode tab can be maintained in a good state.

FIG. 2 is a diagram (1) schematically showing the welding method of the first embodiment. FIG. 2 is a diagram (2) schematically showing the welding method of the first embodiment. It is a figure which shows typically the welding method of 2nd Example. It is a figure which shows typically the welding method of 3rd Example. It is a figure which shows typically the welding method of 4th Example.

The welding method of the first embodiment will be explained with reference to the drawings. 1 and 2 are diagrams schematically showing the welding method of the first embodiment. As shown in FIGS. 1 and 2, the welding method involves welding the first positive electrode tab 12 (an example of the first electrode tab) of the first battery 10 and the second negative electrode tab 23 (an example of the second electrode tab) of the second battery 20. This is a method of welding (one example) with the welding device 100. The first battery 10 and the second battery 20 are stacked in the vertical direction (Z direction). The first battery 10 and the second battery 20 are, for example, lithium ion batteries or nickel metal hydride batteries.

(Configuration of first battery 10)
The configuration of the first battery 10 will be explained. The first battery 10 includes a first battery body 11, a first positive electrode tab 12 extending laterally (X direction) from the first battery body 11, and a first positive electrode tab 12 extending laterally (X direction) from the first battery body 11. The first negative electrode tab 13 is provided with an extending first negative electrode tab 13. In FIGS. 1 and 2, the first negative electrode tab 13 is shown by a virtual line (two-dot chain line). The first positive electrode tab 12 and the first negative electrode tab 13 are arranged side by side with an interval in the depth direction (Y direction) of the drawing.

The first battery body 11 includes a first exterior body 15 and a first power generation element 16 housed in the first exterior body 15. The first exterior body 15 is made of, for example, a resin laminate film. The first exterior body 15 is constructed by bonding a plurality of laminate films together by thermal welding. In a modification, the first exterior body 15 may be made of metal. The first exterior body 15 accommodates a first power generation element 16 and an electrolyte.

The first power generation element 16 includes a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators (all not shown). Each positive electrode is made of a material containing a positive electrode active material, such as LiCoO ₂ . A positive electrode current collector such as aluminum (Al) foil is laminated on each positive electrode. Each negative electrode is made of a material containing a negative electrode active material such as carbon (C). A negative electrode current collector such as copper (Cu) foil is laminated on each negative electrode. Each separator is made of a material containing resin, such as polyethylene (PE) or polypropylene (PP). Since the configuration and power generation mechanism of the first power generation element 16 are well known, further detailed explanation will be omitted.

(Configuration of first positive electrode tab 12)
The configuration of the first positive electrode tab 12 will be explained. The first positive electrode tab 12 is electrically connected to the positive electrode (not shown) of the first power generation element 16 housed in the first exterior body 15 . The first positive electrode tab 12 is made of, for example, an aluminum metal (an example of a first metal) and has a plate shape. The first positive electrode tab 12 is bent at multiple locations. The first positive electrode tab 12 includes a base end portion 31, an intermediate portion 32, and a tip end portion 33 (an example of a first member). The base end portion 31 extends from the first battery main body 11 in the lateral direction (X direction). The intermediate portion 32 extends obliquely downward from the base end portion 31 toward the distal end portion 33. The distal end portion 33 extends from the distal end of the intermediate portion 32 in the lateral direction (X direction).

(Configuration of first negative electrode tab 13)
The configuration of the first negative electrode tab 13 of the first battery 10 is similar to the configuration of the second negative electrode tab 23 of the second battery 20, which will be described later. Therefore, detailed explanation will be omitted.

(Configuration of second battery 20)
The configuration of the second battery 20 will be explained. The second battery 20 includes a second battery body 21, a second negative electrode tab 23 extending laterally (X direction) from the second battery body 21, and a second negative electrode tab 23 extending laterally (X direction) from the second battery body 21. A second positive electrode tab 22 is provided. In FIGS. 1 and 2, the second positive electrode tab 22 is shown by a virtual line (two-dot chain line). The second negative electrode tab 23 and the second positive electrode tab 22 are arranged side by side with an interval in the depth direction (Y direction) of the drawing.

The second battery main body 21 includes a second exterior body 25 and a second power generation element 26 housed in the second exterior body 25. The second exterior body 25 is made of, for example, a resin laminate film. The second exterior body 25 is constructed by bonding a plurality of laminate films together by thermal welding. In a modification, the second exterior body 25 may be made of metal. The second exterior body 25 houses a second power generation element 26 and an electrolyte. The configuration of the second power generation element 26 of the second battery 20 is similar to the configuration of the first power generation element 16 of the first battery 10 described above. Therefore, detailed explanation will be omitted.

(Configuration of second negative electrode tab 23)
The configuration of the second negative electrode tab 23 will be explained. The second negative electrode tab 23 is electrically connected to a negative electrode (not shown) of a second power generation element 26 housed in the second exterior body 25. The second negative electrode tab 23 is made of, for example, a copper-based metal (an example of a second metal) and has a plate shape. The melting point (for example, about 1084° C.) of the copper-based metal forming the second negative electrode tab 23 is higher than the melting point (for example, about 660° C.) of the aluminum-based metal forming the first positive electrode tab 12 described above. The second negative electrode tab 23 is bent at multiple locations. The second negative electrode tab 23 includes a base end portion 41, an intermediate portion 42, an extending portion 43 (an example of a second member), a bent portion 44, and a tip portion 45 (an example of a third member, an example of a welding member). ).

The base end portion 41 extends from the second battery main body 21 in the lateral direction (X direction). The intermediate portion 42 extends obliquely upward from the base end portion 41 toward the extension portion 43 . The extending portion 43 extends from the distal end of the intermediate portion 42 in the lateral direction (X direction). The extending portion 43 is overlapped with the back surface 331 (an example of one surface) of the tip portion 33 of the first positive electrode tab 12 . The tip portion 33 of the first positive electrode tab 12 and the extension portion 43 of the second negative electrode tab 23 are stacked in the vertical direction (Z direction). The bent portion 44 is bent between the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 . The bent portion 44 covers the tip of the tip portion 33 of the first positive electrode tab 12 . The tip portion 45 of the second negative electrode tab 23 extends from the tip of the bent portion 44 in the lateral direction (X direction). The tip portion 45 extends parallel to the extension portion 43. The tip portion 45 and the extension portion 43 are integrally configured to be continuous via the bent portion 44 . The tip 45 of the second negative electrode tab 23 is overlapped with the surface 332 (an example of the other surface) of the tip 33 of the first positive electrode tab 12 . The tip 33 of the first positive electrode tab 12 and the tip 45 of the second negative electrode tab 23 are stacked in the vertical direction (Z direction). The tip portion 33 of the first positive electrode tab 12 is disposed between the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 .

(Configuration of second positive electrode tab 22)
The configuration of the second positive electrode tab 22 of the second battery 20 is similar to the configuration of the first positive electrode tab 12 of the second battery 20 described above. Therefore, detailed explanation will be omitted.

(Configuration of welding device 100)
The configuration of welding apparatus 100 will be explained. Welding apparatus 100 includes a pair of electrodes (first electrode 50 and second electrode 60). The first electrode 50 and the second electrode 60 are arranged facing each other with an interval in the vertical direction (Z direction). The first electrode 50 and the second electrode 60 are connected to a welding power source (not shown). A first positive electrode tab 12 and a second negative electrode tab 23 are arranged between the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60. The tip 33 of the first positive electrode tab 12, the extending portion 43 of the second negative electrode tab 23, and the tip 45 of the second negative electrode tab 23 are stacked in the vertical direction (Z direction) when forming the first electrode. 50 and the tip 61 of the second electrode 60. The tip 51 of the first electrode 50 contacts the extension 43 of the second negative electrode tab 23 . The tip 61 of the second electrode 60 contacts the tip 45 of the second negative electrode tab 23 .

The welding device 100 welds a plurality of members (for example, This device performs resistance spot welding of the tip 33 of the first positive electrode tab 12, the extending portion 43, and the tip 45 of the second negative electrode tab 23. Resistance spot welding is a method in which Joule heat is generated by passing an electric current through multiple members to be welded, and the Joule heat melts and connects the multiple members. Resistance spot welding is well known and further detailed explanation will be omitted.

(Welding method and manufacturing method of battery module 200)
Next, a welding method for welding the first positive electrode tab 12 and the second negative electrode tab 23 will be described. As shown in FIGS. 1 and 2, in the welding method, the first positive electrode tab 12 and the second negative electrode tab 23 are arranged between the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60. The method includes a welding process of resistance spot welding the first positive electrode tab 12 and the second negative electrode tab 23 by flowing the second electrode 60 from the first electrode 50. By passing a current between a pair of electrodes (first electrode 50, second electrode 60), the tip portion 33 of the first positive electrode tab 12 disposed between the pair of electrodes and the extension of the second negative electrode tab 23 are 43 and the tip 45 of the second negative electrode tab 23 are melted and joined.

The welding process includes a pressurizing process in which the first positive electrode tab 12 and the second negative electrode tab 23 are pressurized by the first electrode 50 and the second electrode 60 (see FIG. 2). In the pressurizing process, the first electrode 50 and the second electrode 60 approach each other. In the pressurizing step, the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 are moved toward the tip portion 33 side of the first positive electrode tab 12 by the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60. Apply pressure. The first electrode 50 presses the extension part 43 and the second electrode 60 presses the tip part 45. Pressure is applied to the extension portion 43 and the tip portion 45 so that they approach each other.

In this pressurizing step, the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 are pressurized so that the extending portion 43 and the tip portion 45 do not come into contact with each other. That is, in the pressurizing process, the distance L between the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60 is equal to the thickness t43 of the extending portion 43 of the second negative electrode tab 23 and the thickness t45 of the tip portion 45. The state is maintained longer than the sum of (t43+t45). Therefore, the tip portion 33 of the first positive electrode tab 12 remains between the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 . The tip portion 33 of the first positive electrode tab 12 is sandwiched between the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 . The tip portion 33 of the first positive electrode tab 12 is not removed between the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 . The thickness t43 of the extension portion 43 of the second negative electrode tab 23 and the thickness t45 of the tip portion 45 are the same thickness. The thicknesses t43 and t45 are the thicknesses of the second negative electrode tab 23 before melting. In a modified example, the thicknesses t43 and t45 may be different thicknesses.

By the above welding method, the first positive electrode tab 12 of the first battery 10 and the second negative electrode tab 23 of the second battery 20 are joined. As a result, a battery module 200 including the first battery 10 and the second battery 20 is manufactured. The method for manufacturing battery module 200 includes the above-described welding process and pressurizing process.

[effect]
The welding method and battery module manufacturing method of the first embodiment have been described above. As is clear from the above description, the welding method involves passing a current between the first electrode 50 and the second electrode 60 to bond the tip 33 of the first positive electrode tab 12 and the extending portion of the second negative electrode tab 23. 43 and the tip 45 of the second negative electrode tab 23 by resistance welding. The welding step includes a pressurizing step in which the extending portion 43 and tip portion 45 of the second negative electrode tab 23 are pressurized toward the tip portion 33 side of the first positive electrode tab 12 using the first electrode 50 and the second electrode 60. In the pressurizing step, the distance L between the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60 is equal to the thickness t43 of the extending portion 43 of the second negative electrode tab 23 and the thickness t45 of the tip portion 45. The state is maintained longer than the total (t43+t45).

According to this configuration, even if the first positive electrode tab 12 melts earlier than the second negative electrode tab 23 in the welding process, when the pressurizing process is performed, the extending part 43 and the tip part 45 of the second negative electrode tab 23 melt. The tip portion 33 of the first positive electrode tab 12 is not removed from between. Thereby, the contact state between the first positive electrode tab 12 and the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 can be maintained in a good state. Therefore, the electrical connection between the first positive electrode tab 12 and the second negative electrode tab 23 can be maintained in a good state. It is particularly effective to apply the above welding method to the first positive electrode tab 12 and the second negative electrode tab 23, which are current-carrying members. Further, since there is a large difference in melting point between the aluminum metal of the first positive electrode tab 12 and the copper metal of the second negative electrode tab 23, the above welding method is particularly effective.

Although one embodiment has been described above, the specific aspect is not limited to the above embodiment. In the following description, the same components as those in the above description are designated by the same reference numerals, and the description thereof will be omitted.

(Second example)
In the second embodiment, as shown in FIG. 3, the second negative electrode tab 23 of the second battery 20 does not include the bent portion 44 and the tip portion 45. In the second embodiment, a facing member 85 (another example of the third member, another example of the welding member) is stacked on the surface 332 of the tip portion 33 of the first positive electrode tab 12 . The opposing member 85 extends parallel to the extending portion 43 in the lateral direction (X direction). The opposing member 85 is configured separately from the second negative electrode tab 23. The opposing member 85 is made of, for example, a copper-based metal and has a plate shape. The opposing member 85 faces the extending portion 43 of the second negative electrode tab 23 via the tip portion 33 of the first positive electrode tab 12 .

In the pressing step, the extending portion 43 of the second negative electrode tab 23 and the opposing member 85 are pressed against the tip portion 33 of the first positive electrode tab 12 by the first electrode 50 and the second electrode 60 . In the pressurizing process, the distance L between the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60 is equal to the thickness t43 of the extending portion 43 of the second negative electrode tab 23 and the thickness t85 of the opposing member 85. The state is maintained longer than the sum of (t43+t85). The thickness t85 is the thickness before the facing member 85 is melted. The thicknesses t43 and t85 are the same thickness. In a modified example, the thicknesses t43 and t85 may be different thicknesses. With the above configuration as well, the electrical connection state between the first positive electrode tab 12 and the second negative electrode tab 23 can be maintained in a good state.

(Third example)
In the third embodiment, as shown in FIG. 4, the back surface 431 of the extending portion 43 of the second negative electrode tab 23 (that is, the surface of the extending portion 43 on the opposite side to the first positive electrode tab 12 side) is connected to the support member 70. Supported by The upper surface of the support member 70 is in contact with the back surface 431 of the extending portion 43 of the second negative electrode tab 23 . The support member 70 has a substantially cylindrical shape. The support member 70 is arranged around the first electrode 50. The support member 70 goes around the first electrode 50 so as to surround the first electrode 50 .

The support member 70 is made of, for example, an insulating material. Further, the support member 70 is made of a material having a thermal conductivity lower than that of the metal (for example, copper-based metal) constituting the second negative electrode tab 23 . Furthermore, the support member 70 is made of a material having a melting point higher than the melting point of the metal (for example, copper-based metal) that constitutes the second negative electrode tab 23 . The support member 70 is made of ceramic or alumina, for example.

Further, in the third embodiment, a heat absorbing member 72 is superimposed on the surface 332 of the tip portion 33 of the first positive electrode tab 12 . The heat absorbing member 72 is in contact with the tip 33 of the first positive electrode tab 12 . The heat absorbing member 72 absorbs heat from the first positive electrode tab 12 . The heat absorbing member 72 is spaced apart from the second negative electrode tab 23. In a modification, the heat absorbing member 72 may be in contact with the second negative electrode tab 23.

The heat absorbing member 72 is configured in a block shape. The heat absorbing member 72 is made of a metal having a thermal conductivity higher than that of the metal (for example, aluminum-based metal) constituting the first positive electrode tab 12 . The heat absorbing member 72 is made of a metal having a melting point higher than that of the metal (for example, aluminum-based metal) constituting the first positive electrode tab 12 . The heat absorbing member 72 is made of, for example, copper-based metal, gold-based metal, silver-based metal, iron-based metal, or the like.

The second embodiment has been described above. In the second embodiment, since the second negative electrode tab 23 is supported by the support member 70, it is possible to suppress the second member from warping during the welding process. Further, in the second embodiment, the support member 70 is arranged around the first electrode 50. Since the second negative electrode tab 23 becomes high temperature around the first electrode 50, the second negative electrode tab 23 becomes easily deformed, but being supported by the support member 70 suppresses the deformation of the second negative electrode tab 23. be able to.

Further, in the third embodiment, the heat of the first positive electrode tab 12 is absorbed by the heat absorbing member 72. According to this configuration, the timing at which the first member melts can be delayed. Therefore, the timing at which the first positive electrode tab 12 melts can be brought closer to the timing at which the second negative electrode tab 23 melts. As a result, the first positive electrode tab 12 and the second negative electrode tab 23 can be bonded well. The heat absorbing member 72 is made of a metal (eg, copper-based metal) having a higher thermal conductivity than that of the metal (eg, aluminum-based metal) constituting the first positive electrode tab 12 . According to this configuration, the heat of the first positive electrode tab 12 can be quickly absorbed.

(Fourth example)
In the fourth embodiment, as shown in FIG. 5, the heat absorbing member 72 has a substantially cylindrical shape. The heat absorbing member 72 is arranged around the second electrode 60. The heat absorbing member 72 goes around the second electrode 60 so as to surround the second electrode 60 . According to this configuration, the heat of the first positive electrode tab 12 is absorbed around the second electrode 60, which tends to reach a high temperature, so that the heat of the first positive electrode tab 12 can be quickly absorbed.

(Modified example)
(1) The metals forming each of the first positive electrode tab 12 and the second negative electrode tab 23 are not particularly limited. Further, the metal forming the facing member 85 is not particularly limited. The first positive electrode tab 12 may be made of, for example, a tin-based metal. The second negative electrode tab 23 and the opposing member 85 may be made of, for example, a nickel-based metal (an example of a third metal). The melting point of the copper-based metal (e.g., approximately 1084°C) or the melting point of the nickel-based metal (e.g., approximately 1455°C) that constitutes the second negative electrode tab 23 and the opposing member 85 is the same as that of the aluminum-based metal that constitutes the first positive electrode tab 12. (eg, about 660°C) or the melting point of tin-based metals (eg, about 232°C). In a modification, the second negative electrode tab 23 and the facing member 85 may be made of different metals (for example, a copper-based metal and a nickel-based metal). Further, the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 may be made of different metals (for example, a copper-based metal and a nickel-based metal).

(2) The positions of the first electrode 50 and the second electrode 60 can be replaced with each other. The first electrode 50 may be arranged on the upper side, and the second electrode 60 may be arranged on the lower side.

(3) The tip portion 45 of the second negative electrode tab 23 of the second battery 20 may be supported by a support member (not shown). Further, the facing member 85 may be supported by a support member (not shown). These support members may have a configuration in which the support member 70 that supports the extension portion 43 of the second negative electrode tab 23 described above is turned upside down. According to this configuration, the first positive electrode tab 12 and the second negative electrode tab 23 can be supported from both upper and lower sides.

(4) The heat absorbing member 72 may be cooled by a cooling device (not shown).

Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims as filed. Further, the techniques illustrated in this specification or the drawings can achieve multiple objectives simultaneously, and achieving one of the objectives has technical utility in itself.

10: first battery, 11: first battery main body, 12: first positive electrode tab, 13: first negative electrode tab, 15: first exterior body, 16: first power generation element, 20: second battery, 21: first 2 battery main body, 22: second positive electrode tab, 23: second negative electrode tab, 25: second exterior body, 26: second power generation element, 50: first electrode, 60: second electrode, 70: support member, 72 : Endothermic member, 85: Opposing member, 100: Welding device

Claims (11)

A welding method for welding a first member, a second member stacked on one side of the first member, and a third member stacked on the other side of the first member, comprising:
The first member is made of a first metal,
The second member is made of a second metal having a melting point higher than the melting point of the first metal,
The third member is made of a third metal having a melting point higher than the melting point of the first metal or the second metal,
The first member, the second member, and the third member are arranged between the first member, the second member, and the third member by passing a current between the pair of electrodes. Equipped with a welding process for resistance welding parts,
In the welding step, the first member and the third member are pressed against the first member by the tip of one electrode and the tip of the other electrode of the pair of electrodes. a pressurizing step of resistance welding the second member and the third member ;
In the pressurizing step, the tip of the one electrode contacts the surface of the second member opposite to the first member, and the tip of the other electrode contacts the surface of the third member opposite to the first member. and the distance between the tip of the one electrode and the tip of the other electrode is longer than the sum of the thickness of the second member and the thickness of the third member. A welding method , wherein the first member, the second member, and the third member are resistance welded while the state is maintained. The welding method according to claim 1,
The welding method, wherein the third member is a member of the second metal bent from the second member and extending parallel to the second member. The welding method according to claim 1 or 2 ,
the first member is a part of an electrode tab of a first battery;
A welding method, wherein the second member is part of an electrode tab of a second battery that is connected to the electrode tab of the first battery. The welding method according to any one of claims 1 to 3 ,
A welding method, wherein a surface of the second member opposite to the first member is supported by a support member. The welding method according to claim 4 ,
In the welding method, the support member is arranged around an electrode of the pair of electrodes that presses the second member. The welding method according to any one of claims 1 to 5 ,
A welding method, wherein the heat of the first member is absorbed by an endothermic member. The welding method according to claim 6 ,
The welding method, wherein the heat absorbing member is made of a metal having a higher thermal conductivity than the first metal. The welding method according to any one of claims 1 to 7 ,
the first metal is an aluminum-based metal,
A welding method, wherein the second metal is a copper-based metal. A method for manufacturing a battery module comprising: a first battery having a first electrode tab; and a second battery having a second electrode tab connected to the first electrode tab.
a welding step of welding the first electrode tab, the second electrode tab stacked on one side of the first electrode tab, and a welding member stacked on the other side of the first electrode tab; We are equipped with
The first electrode tab is made of a first metal,
The second electrode tab is made of a second metal having a melting point higher than the melting point of the first metal,
The welding member is made of a third metal or the second metal having a melting point higher than the melting point of the first metal,
In the welding process, the first electrode tab, the second electrode tab, and the welding member are arranged between the pair of electrodes, and by passing a current between the pair of electrodes, the first electrode tab and the welding member are disposed between the pair of electrodes. resistance welding a second electrode tab and the welding member;
In the welding step, the second electrode tab and the welding member are pressed against the first electrode tab side by the tip of one electrode and the tip of the other electrode of the pair of electrodes, and then the first electrode tab is pressed. and a pressurizing step of resistance welding the second electrode tab and the welding member ,
In the pressurizing step, the tip of the one electrode contacts the surface of the second electrode tab opposite to the first electrode tab, and the tip of the other electrode contacts the first electrode tab of the welding member. While in contact with the opposite surface, the distance between the tip of the one electrode and the tip of the other electrode is greater than the sum of the thickness of the second electrode tab and the thickness of the welding member. A manufacturing method , wherein the first electrode tab, the second electrode tab, and the welding member are resistance welded while the long state is maintained. The manufacturing method according to claim 9,
In the manufacturing method, the welding member is constituted by a member of the second metal bent from the second electrode tab and extending parallel to the second electrode tab. The manufacturing method according to claim 9 or 10 ,
A manufacturing method, wherein the second electrode tab includes the welding member.

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