JP2021150247A - Welding method and battery module manufacturing method - Google Patents

Abstract

To provide a technique capable of maintaining a good contact state between members.SOLUTION: A welding method includes a welding step of resistance-welding a first member, a second member, and a third member by passing an electric current between a pair of electrodes in a state in which the first member, the second member, and the third member are arranged between the pair of electrodes. The welding step includes a pressurizing step of pressurizing the second member and the third member toward the first member side by the tip of one electrode and the tip of the other electrode of the pair of electrodes. In the pressurizing step, a 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.SELECTED DRAWING: Figure 2

Description

The techniques disclosed herein relate to welding methods and methods of manufacturing battery modules.

Patent Document 1 discloses a welding method. In the welding method of Patent Document 1, the first member, the second member superposed on the back surface of the first member, and the third member superposed on the surface of the first member are welded. The first member is made of an 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 the aluminum-based metal. In the welding method of Patent Document 1, a first member, a second member, and a third member are formed by passing an electric 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 is equipped with a welding process in which three members are resistance welded. The welding step includes a pressurizing step of pressurizing the second member and the third member toward the first member side by the tip of one electrode of the pair of electrodes and the tip of the other electrode.

Japanese Unexamined Patent Publication No. 7-328774

In the welding method of Patent Document 1, the first member is excluded 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 and the second member and the third member may deteriorate. For example, the second member and the third member may come into direct contact with each other without going through the first member. Then, for example, when the first member and the second member are energized, it is conceivable that the first member and the second member have poor contact. Therefore, the present specification provides a technique capable of maintaining a good contact state between members.

The welding method disclosed in the present specification includes a first member, a second member superposed on one surface of the first member, and a third member superposed on the other surface of the first member. It may be welded. The first member may be made of a first metal. The second member may be composed of a second metal having a melting point higher than the melting point of the first metal. The third member may be composed of a third metal having a melting point higher than the melting point of the first metal or the second metal. In the welding method, the first member and the second member are formed by passing an electric current between the pair of electrodes while the first member, the second member, and the third member are arranged between the pair of electrodes. And the third member may be provided with a welding step of resistance welding. The welding step may include a pressurizing step of pressurizing the second member and the third member toward the first member side by the tip of one electrode of the pair of electrodes and the tip of the other electrode. .. 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. May be good.

According to this configuration, even if the first member melts faster than the second member and the third member in the welding process, the first member is placed between the second member and the third member when the pressurizing process is executed. Remains. The first member is not excluded from between the second member and the third member. Therefore, it is possible to prevent the second member and the third member from coming into direct contact with each other without going through the first member. Thereby, the contact state between the first member and the second member and the third member can be maintained in a good state.

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

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

The surface of the second member opposite to the first member side may be supported by the support member.

Since the second member is pressurized in a molten state in the welding process, it is conceivable that the second member is deformed and warped during the welding process. However, since the second member is supported by the support member, it is possible to prevent the second member from warping.

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

Around the electrode that pressurizes the second member, the second member becomes particularly hot, so that it is easily deformed. However, since the second member is supported by the support member around the electrode that pressurizes the second member, it is possible to suppress the deformation of the second member.

The heat of the first member may be absorbed by the endothermic member.

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

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

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

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

According to this configuration, the above welding method can be applied to aluminum-based metal and copper-based metal suitable for the electrode tab of the battery. Since the difference in melting point between the aluminum-based metal and the copper-based metal is large, the above welding method is particularly effective.

The present specification discloses a method of 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. In this manufacturing method, the first electrode tab, the second electrode tab overlapped on one surface of the first electrode tab, and the metal member overlapped on the other surface of the first electrode tab are formed. It may be provided with a welding process for welding. The first electrode tab may be made of a first metal. The second electrode tab may be composed of a second metal having a melting point higher than the melting point of the first metal. The metal member may be composed 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 a current is passed between the pair of electrodes to cause the first electrode tab and the metal member. The second electrode tab and the metal member may be resistance welded. Even if the welding step includes a pressurizing step of pressurizing the second electrode tab and the metal member to the first electrode tab side by the tip of one electrode and the 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. May be good.

According to this configuration, the first electrode tab remains between the second electrode tab and the metal member when the pressurizing step is executed. A part of the first electrode tab is not excluded 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 by the second electrode tab. Therefore, the electrical connection state between the first electrode tab and the second electrode tab can be maintained in a good state.

It is a figure which shows typically the welding method of 1st Example (1). It is a figure which shows typically the welding method of 1st Example (2). 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 described 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 includes a first positive electrode tab 12 of the first battery 10 (an example of the first electrode tab) and a second negative electrode tab 23 of the second battery 20 (of the second electrode tab). An example) is a method of welding with a 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, a lithium ion battery or a nickel hydrogen battery.

(Structure of 1st battery 10)
The configuration of the first battery 10 will be described. The first battery 10 has a first battery main body 11, a first positive electrode tab 12 extending in the lateral direction (X direction) from the first battery main body 11, and the same lateral direction (X direction) from the first battery main body 11. It includes an extended first negative electrode tab 13. In FIGS. 1 and 2, the first negative electrode tab 13 is indicated by a virtual line (dashed-dotted line). The first positive electrode tab 12 and the first negative electrode tab 13 are arranged side by side at intervals 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 laminated film. The first exterior body 15 is formed by laminating a plurality of laminated films by heat welding. In the modified example, the first exterior body 15 may be made of metal. The first exterior body 15 houses the first power generation element 16 and the electrolytic solution.

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 composed of a material containing a positive electrode active material such as _{LiCoO 2.} A positive electrode current collector such as an aluminum (Al) foil is laminated on each positive electrode. Each negative electrode is composed of a material containing a negative electrode active material such as carbon (C). A negative electrode current collector such as a copper (Cu) foil is laminated on each negative electrode. Each separator is made of a material containing a resin such as polyethylene (PE) or polypropylene (PP). Since the configuration of the first power generation element 16 and the power generation mechanism are well known, further detailed description thereof will be omitted.

(Structure of 1st positive electrode tab 12)
The configuration of the first positive electrode tab 12 will be described. 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 formed of, for example, an aluminum-based metal (an example of the first metal) in a plate shape. The first positive electrode tab 12 is bent at a plurality of points. 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 the first member). The base end portion 31 extends in the lateral direction (X direction) from the first battery body 11. The intermediate portion 32 extends obliquely downward from the base end portion 31 toward the tip end portion 33. The tip portion 33 extends laterally (X direction) from the tip of the intermediate portion 32.

(Structure of 1st negative electrode tab 13)
The configuration of the first negative electrode tab 13 of the first battery 10 is the same as the configuration of the second negative electrode tab 23 of the second battery 20, which will be described later. Therefore, detailed description will be omitted.

(Structure of 2nd battery 20)
The configuration of the second battery 20 will be described. The second battery 20 has a second battery body 21, a second negative electrode tab 23 extending laterally (X direction) from the second battery body 21, and the second battery body 21 in the lateral direction (X direction). It includes an extended second positive electrode tab 22. In FIGS. 1 and 2, the second positive electrode tab 22 is indicated by an imaginary line (dashed-dotted line). The second negative electrode tab 23 and the second positive electrode tab 22 are arranged side by side at intervals in the depth direction (Y direction) of the drawing.

The second battery 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 laminated film. The second exterior body 25 is formed by laminating a plurality of laminated films by heat welding. In the modified example, the second exterior body 25 may be made of metal. The second exterior body 25 contains the second power generation element 26 and the electrolytic solution. The configuration of the second power generation element 26 of the second battery 20 is the same as the configuration of the first power generation element 16 of the first battery 10 described above. Therefore, detailed description will be omitted.

(Structure of the second negative electrode tab 23)
The configuration of the second negative electrode tab 23 will be described. The second negative electrode tab 23 is electrically connected to the negative electrode (not shown) of the second power generation element 26 housed in the second exterior body 25. The second negative electrode tab 23 is formed of, for example, a copper-based metal (an example of the second metal) in a plate shape. The melting point of the copper-based metal constituting the second negative electrode tab 23 (for example, about 1084 ° C.) is higher than the melting point of the aluminum-based metal constituting the first positive electrode tab 12 described above (for example, about 660 ° C.). The second negative electrode tab 23 is bent at a plurality of points. 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 welded member). ) And.

The base end portion 41 extends laterally (X direction) from the second battery body 21. The intermediate portion 42 extends obliquely upward from the base end portion 41 toward the extending portion 43. The extending portion 43 extends in the lateral direction (X direction) from the tip of the intermediate portion 42. 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 extending portion 43 of the second negative electrode tab 23 are laminated 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 45 of the second negative electrode tab 23 extends laterally (X direction) from the tip of the bent 44. The tip portion 45 extends parallel to the extending portion 43. The tip portion 45 and the extending portion 43 are continuously and integrally formed 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 laminated in the vertical direction (Z direction). The tip 33 of the first positive electrode tab 12 is arranged between the extending portion 43 of the second negative electrode tab 23 and the tip 45.

(Structure of the second positive electrode tab 22)
The configuration of the second positive electrode tab 22 of the second battery 20 is the same as the configuration of the first positive electrode tab 12 of the second battery 20 described above. Therefore, detailed description will be omitted.

(Structure of Welding Device 100)
The configuration of the welding apparatus 100 will be described. The welding device 100 includes a pair of electrodes (first electrode 50 and second electrode 60). The first electrode 50 and the second electrode 60 are arranged so as to face each other at intervals 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 first electrode 33 in a state where 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 laminated in the vertical direction (Z direction). It is arranged between the tip 51 of the 50 and the tip 61 of the second electrode 60. The tip 51 of the first electrode 50 contacts the extending portion 43 of the second negative electrode tab 23. The tip 61 of the second electrode 60 comes into contact with the tip 45 of the second negative electrode tab 23.

The welding device 100 has a plurality of members (for example, for example) arranged between the first electrode 50 and the second electrode 60 by passing a current between the pair of electrodes (first electrode 50, second electrode 60). This is a device for resistance spot welding of the tip portion 33 of the first positive electrode tab 12, the extending portion 43 of the second negative electrode tab 23, and the tip portion 45). Resistance spot welding is a method in which Joule heat is generated by passing an electric current through a plurality of members to be welded, and the Joule heat melts and connects the plurality of members. Since resistance spot welding is well known, further detailed description 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. A welding step is provided in which the first positive electrode tab 12 and the second negative electrode tab 23 are resistance spot welded by flowing the second electrode 60 from the first electrode 50. By passing a current between the pair of electrodes (first electrode 50, second electrode 60), the tip 33 of the first positive electrode tab 12 arranged between the pair of electrodes and the second negative electrode tab 23 extend. The portion 43 and the tip portion 45 of the second negative electrode tab 23 are melted and joined.

The welding step includes a pressurizing step of pressurizing the first positive electrode tab 12 and the second negative electrode tab 23 by the first electrode 50 and the second electrode 60 (see FIG. 2). In the pressurizing step, the first electrode 50 and the second electrode 60 come close to each other. In the pressurizing step, the tip 51 of the first electrode 50 and the tip 61 of the second electrode 60 bring the extending portion 43 and the tip 45 of the second negative electrode tab 23 to the tip 33 side of the first positive electrode tab 12. Pressurize. The first electrode 50 pressurizes the extending portion 43, and the second electrode 60 pressurizes the tip portion 45. Pressurize both so that the extending portion 43 and the tip portion 45 approach each other.

In this pressurizing step, the extending portion 43 and the tip portion 45 are pressurized so that the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 do not come into contact with each other. That is, 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 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 longer than the total (t43 + t45) of and is maintained. 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 33 of the first positive electrode tab 12 is sandwiched between the extending portion 43 and the tip 45 of the second negative electrode tab 23. The tip 33 of the first positive electrode tab 12 is not excluded between the extending portion 43 of the second negative electrode tab 23 and the tip 45. The thickness t43 of the extending 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 before the second negative electrode tab 23 is melted. In the modified example, the thicknesses t43 and t45 may be different.

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, the battery module 200 including the first battery 10 and the second battery 20 is manufactured. The method for manufacturing the battery module 200 includes the welding step and the pressurizing step described above.

[effect]
The welding method and the battery module manufacturing method of the first embodiment have been described above. As is clear from the above description, in the welding method, the tip portion 33 of the first positive electrode tab 12 and the extending portion of the second negative electrode tab 23 are formed by passing an electric current between the first electrode 50 and the second electrode 60. A welding step of resistance welding the 43 and the tip end portion 45 of the second negative electrode tab 23 is provided. The welding step includes a pressurizing step of pressurizing the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 to the tip portion 33 side of the first positive electrode tab 12 by 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 the thickness t43 of the extending portion 43 of the second negative electrode tab 23 and the thickness t45 of the tip portion 45. A state longer than the total (t43 + t45) is maintained.

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, the extending portion 43 and the tip portion 45 of the second negative electrode tab 23 when the pressurizing step is executed. The tip 33 of the first positive electrode tab 12 is not excluded from the space. As a result, 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 state 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 energizing members. Further, since the difference in melting point between the aluminum-based metal of the first positive electrode tab 12 and the copper-based metal of the second negative electrode tab 23 is large, the above welding method is particularly effective.

Although one embodiment has been described above, the specific embodiment is not limited to the above embodiment. In the following description, the same components as those in the above description will be designated by the same reference numerals and 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, the facing member 85 (another example of the third member, another example of the welding member) is superposed on the surface 332 of the tip portion 33 of the first positive electrode tab 12. The facing member 85 extends parallel to the extending portion 43 in the lateral direction (X direction). The facing member 85 is formed separately from the second negative electrode tab 23. The facing member 85 is made of, for example, a copper-based metal in a plate shape. The facing 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 pressurizing step, the extending portion 43 of the second negative electrode tab 23 and the facing member 85 are pressurized to the tip end portion 33 side of the first positive electrode tab 12 by 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 the thickness t43 of the extending portion 43 of the second negative electrode tab 23 and the thickness t85 of the facing member 85. The state is maintained longer than the total 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 the modified example, the thicknesses t43 and t85 may be different. Even with the above configuration, the electrical connection state of 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 opposite to the first positive electrode tab 12 side) is the support member 70. Is 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 is formed in 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 the thermal conductivity of the metal (for example, copper-based metal) constituting the second negative electrode tab 23. Further, 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) constituting the second negative electrode tab 23. The support member 70 is made of, for example, ceramic or alumina.

Further, in the third embodiment, the endothermic member 72 is superposed on the surface 332 of the tip portion 33 of the first positive electrode tab 12. The endothermic member 72 is in contact with the tip 33 of the first positive electrode tab 12. The heat absorbing member 72 absorbs the heat of the first positive electrode tab 12. The endothermic member 72 is separated from the second negative electrode tab 23. In the modified example, the endothermic member 72 may be in contact with the second negative electrode tab 23.

The endothermic 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, an aluminum-based metal) constituting the first positive electrode tab 12. The endothermic member 72 is made of a metal having a melting point higher than the melting point of the metal (for example, an aluminum-based metal) constituting the first positive electrode tab 12. The endothermic member 72 is made of, for example, a copper-based metal, a gold-based metal, a silver-based metal, an 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 prevent 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 hot around the first electrode 50, the second negative electrode tab 23 is easily deformed, but the support 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 close 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 satisfactorily joined. The heat absorbing member 72 is made of a metal (for example, a copper-based metal) having a thermal conductivity higher than that of the metal (for example, an 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 endothermic member 72 is formed in a substantially cylindrical shape. The endothermic member 72 is arranged around the second electrode 60. The endothermic 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 become hot, so that the heat of the first positive electrode tab 12 can be quickly absorbed.

(Modification example)
(1) The metal constituting each of the first positive electrode tab 12 and the second negative electrode tab 23 is not particularly limited. Further, the metal constituting 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 facing member 85 may be made of, for example, a nickel-based metal (an example of the third metal). The melting point of the copper-based metal constituting the second negative electrode tab 23 and the facing member 85 (for example, about 1084 ° C.) or the melting point of the nickel-based metal (for example, about 1455 ° C.) is the aluminum-based metal constituting the first positive electrode tab 12. Is higher than the melting point of (for example, about 660 ° C.) or the melting point of tin-based metals (for example, about 232 ° C.). In the modified example, 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 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 extending 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 the upper and lower sides.

(4) The endothermic 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 examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above. The technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques illustrated in the present specification or drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

10: 1st battery, 11: 1st battery body, 12: 1st positive electrode tab, 13: 1st negative electrode tab, 15: 1st exterior body, 16: 1st power generation element, 20: 2nd battery, 21: 1st 2 Battery body, 22: 2nd positive electrode tab, 23: 2nd negative electrode tab, 25: 2nd exterior body, 26: 2nd power generation element, 50: 1st electrode, 60: 2nd electrode, 70: support member, 72 : Heat absorbing member, 85: Opposing member, 100: Welding device

Claims (9)

A welding method for welding a first member, a second member superposed on one surface of the first member, and a third member superposed on the other surface of the first member.
The first member is made of a first metal and is composed of a first metal.
The second member is composed of a second metal having a melting point higher than the melting point of the first metal.
The third member is composed of a third metal or the second metal having a melting point higher than the melting point of the first metal.
The first member, the second member, and the third member are formed by passing an electric 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 is equipped with a welding process for resistance welding of members.
The welding step includes a pressurizing step of pressurizing the second member and the third member toward the first member side by the tip of one electrode of the pair of electrodes and the tip of the other electrode.
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. , Welding method. The welding method according to claim 1.
The first member is a part of the electrode tab of the first battery.
A welding method in which the second member is a part of an electrode tab of a second battery connected to the electrode tab of the first battery. The welding method according to claim 1 or 2.
A welding method in which a surface of the second member opposite to the first member side is supported by a support member. The welding method according to claim 3.
A welding method in which the support member is arranged around an electrode that pressurizes the second member of the pair of electrodes. The welding method according to any one of claims 1 to 4.
A welding method in which the heat of the first member is absorbed by the endothermic member. The welding method according to claim 5.
A welding method in which the endothermic member is made of a metal having a thermal conductivity higher than that of the first metal. The welding method according to any one of claims 1 to 6.
The first metal is an aluminum-based metal,
A welding method in which the second metal is a copper-based metal. A method for manufacturing a battery module including 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 overlapped on one surface of the first electrode tab, and the welding member overlapped on the other surface of the first electrode tab. Prepared
The first electrode tab is made of a first metal and is composed of a first metal.
The second electrode tab is composed of a second metal having a melting point higher than the melting point of the first metal.
The welded member is composed 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 and the welding member are arranged between the pair of electrodes by passing a current between the pair of electrodes in a state where the first electrode tab, the second electrode tab, and the welding member are arranged between the pair of electrodes. The second electrode tab and the welding member are resistance welded,
The welding step includes a pressurizing step of pressurizing the second electrode tab and the welding member toward the first electrode tab side by the tip of one electrode and the 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 electrode tab and the thickness of the welded member. ,Production method. The manufacturing method according to claim 8.
A manufacturing method in which the second electrode tab includes the welded member.

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