JP2009158445A - Method of manufacturing battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage of a unit cell due to thermal stress by stably welding the unit cell to a connection fitting, and preventing an harmful effect due to heat generation of a welding part of the unit cell, and also to extend a replacement time of a welding electrode by reducing consumption of the welding electrode. <P>SOLUTION: In a method of manufacturing a battery pack, connection fittings 20 are spot-welded to electrodes 19 of adjoining unit cells 10, and a plurality of unit cells 10 are connected through the connection fittings 20. In the manufacturing method, welding parts 23 of the connection fitting 20 are pressed against a surface of the unit cell 10 by welding and pressing means 40; a pair of electrodes 50 carrying a welding current are brought into contact with parts located on a surface of the connection fitting 20 and different from the welding parts 23; the welding current is carried to the connection fitting 20 by the pair of electrodes 50; the welding current carried to the connection fitting 20 is carried to the electrode 19 of the unit cell 10 by the welding parts 23 pressed by the welding and pressing means 40; and the welding part 23 of the connection fitting 20 is spot-welded to the electrode 19 of the unit cell 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an assembled battery in which a plurality of batteries are connected via a connection fitting.

  An assembled battery produced by connecting a large number of unit cells with connection fittings is mainly used for an electric vehicle such as a hybrid car. It is important that the assembled battery with this structure is firmly connected in a low resistance state. This is because a large connection resistance not only lowers the output, but also generates Joule heat and generates heat, and furthermore, the power cannot be effectively used due to resistance loss. A battery module that connects a plurality of batteries in a straight line via a connection fitting has been developed (see Patent Document 1).

The assembled battery described in Patent Document 1 is connected by spot welding a connection fitting 80 to a unit cell 90 as shown in FIGS. As shown in FIG. 2, the connection fitting 80 is produced by press-molding a metal plate into a shape that connects the cylindrical portion 84 to the outer periphery of the disk 83. As shown in the cross-sectional view of FIG. 1, the connection fitting 80 welds a first welded portion 81 that is a disk 83 to a sealing plate 92 of a unit cell 90, and a second welded portion 82 that is a cylindrical portion 84. It welds to the outer peripheral surface of the armored can 91 of the other unit cell 90, and the adjacent unit cells 90 are connected linearly in series.
JP-A-10-106533

In the above battery module, the unit cells 90 are connected in series by the connection fitting 80 in the following steps.
(1) The first welded portion 81 of the connection fitting 80 is disposed on the sealing plate 92 that is an end face electrode of one unit cell 90.
(2) The pair of welding electrodes are pressed against the first welding part 81, and a current is passed through the welding electrode to weld the first welding part 81 to the sealing plate 92.
(3) The lower end of the unit cell 90 to be connected is inserted into the cylindrical portion 84 of the connection fitting 80.
(4) A pair of welding electrodes is pressed against the second welding portion 82 that is the cylindrical portion 84, and current is passed through the welding electrodes to weld the second welding portion 82 to the outer peripheral surface of the unit cell 90.

  The above-described manufacturing method has a drawback that the welding electrode is extremely consumed, and the connection fitting cannot be reliably welded to the unit cell in a stable and preferable state for a long time. Welding electrodes are periodically replaced, and each time they are replaced, it is necessary to adjust the welding state by spot welding several times on a trial basis, and this process has the disadvantage of wasting many unit cells. there were.

  In addition, the heat generated at the spot-welded part has a detrimental effect on the unit cell. This is because the heat generated in the welded portion damages the internal electrodes due to thermal stress. In an assembled battery in which a large number of unit cells are connected in series as in a hybrid car, a failure of a specific unit cell renders the entire assembled battery unusable. Therefore, it is very important in the method of manufacturing an assembled battery how to reduce the harmful effects of the heat of the unit cells in the welding process, in other words, how to reduce the damage caused by the heat generation of the welded portion.

  The present invention was developed for the purpose of solving the above drawbacks, and an important object of the present invention is to reduce the consumption of the welding electrode and to increase the replacement period of the welding electrode, and to stabilize the connection fitting. Another object of the present invention is to provide a method of manufacturing an assembled battery that can be welded to a unit cell, and that can prevent damage caused by heat generation at a welded portion of the unit cell and prevent damage to the unit cell due to thermal stress.

In order to achieve the above-described object, the battery pack manufacturing method of the present invention manufactures the battery pack by the following method.
In the method for manufacturing the assembled battery, the connection fitting 20 is spot welded to the electrode 19 of the adjacent unit cell 10, and the plurality of unit cells 10 are connected via the connection fitting 20. In this manufacturing method, the welded portion 23 of the connection fitting 20 is pressed against the surface of the unit cell 10 by the welding pressing tool 40, and a pair of welding currents are supplied to the surface of the connection fitting 20 and different from the welding point 28. The electrode 50 is contacted, a welding current is passed through the connection fitting 20 with the pair of electrodes 50, and the welding cell 23 presses the welding current passed through the connection fitting 20 with the welding pressing tool 40. The electrode 19 is energized, and the welded portion 23 of the connection fitting 20 is spot welded to the electrode 19 of the unit cell 10.

  In the method for manufacturing an assembled battery according to claim 2 of the present invention, the unit cells 10 are arranged in a straight line, the connection fitting 20 is disposed between the unit cells 10, and the first welded portion 23 </ b> A of the connection fitting 20 is provided. Welding to one unit cell 10, welding the second welded portion 23B to the other unit cell 10, and connecting adjacent unit cells 10 in series.

  In the method of manufacturing the assembled battery according to claim 3 of the present invention, the unit cell 10 connected by the connection fitting 20 is a cylindrical cell in which the opening of the outer can 11 is closed by the sealing plate 12. The first welded portion 23A of the connection fitting 20 is welded to the sealing plate 12 of the cylindrical battery that is, and the second welded portion 23B is welded to the bottom of the outer can 11 of the cylindrical battery that is the other unit cell 10. To do.

  In the method for manufacturing an assembled battery according to claim 4 of the present invention, an insulating material 30 that insulates the outer periphery of the unit cell 10 is disposed between the unit cells 10 that are linearly connected. The electrode 50 is brought into contact with the surface of the connection fitting 20 that is insulated from the battery 10 to weld the welded portion 23.

  In the assembled battery manufacturing method according to the fifth aspect of the present invention, the welding pressing tool 40 is disposed between the pair of electrodes 50 to weld the connection fitting 20 to the unit cell 10.

  The method for manufacturing an assembled battery according to the present invention can reduce the consumption of the welding electrode and extend the time for replacing the welding electrode. Further, there is a feature that the connection fitting can be stably welded to the unit cell. That is, the manufacturing method of the present invention presses the welded portion of the connection fitting on the surface of the unit cell with the welding pressing tool, and further causes a welding current to flow on the surface of the connection fitting that is different from the welding point. The electrode is brought into contact, a welding current is passed through the connection fitting with a pair of electrodes, and the unit cell is energized at the welded portion where the welding current applied to the connection fitting is pressed by a welding pressing tool. This is because spot welding is performed on the welded portion.

  In addition, the method for manufacturing an assembled battery according to the present invention also realizes a feature that can prevent damage due to heat stress and prevent damage to the unit cell due to heat stress. That is, since the manufacturing method of the present invention presses and welds a welding pressing tool different from the electrode to be energized to the welding part of the connection fitting, the welding heat generated in the welding part can be radiated by this welding pressing tool. Because.

  Furthermore, in the method for manufacturing an assembled battery according to claim 2 of the present invention, the unit cells are arranged in a straight line, the connection fitting is disposed between the unit cells, and the first welded portion of the connection fitting is connected to one unit cell. Since the adjacent unit cells are connected in series by welding the second welded portion to the other unit cell, the adjacent unit cells can be connected in a straight line while being electrically connected by the connection fitting.

  Furthermore, in the method for manufacturing an assembled battery according to claim 3 of the present invention, the unit cell connected by the connection fitting is a cylindrical cell in which the opening of the outer can is closed with a sealing plate, and the unit cell is a cylinder. The first welded portion of the connection fitting is welded to the sealing plate of the battery, and the second welded portion is welded to the bottom of the outer can of the cylindrical battery that is the other unit cell. Since the batteries are not electrically connected in series with the connection fitting, they can be connected in a straight line.

  Furthermore, in the method for manufacturing an assembled battery according to claim 4 of the present invention, an insulating material that insulates the outer peripheral portion of the unit cell is disposed between the unit cells connected in a straight line, and the insulating material is used to remove the unit cell from the unit cell. Since the electrode is brought into contact with the surface of the connection fitting to be insulated and the welded portion is welded, the welded portion of the connection fitting pressed by the welding pressing tool can be efficiently and reliably welded to the unit cell. This is because the electrode contact portion of the connection fitting can be insulated from the unit cell and the current can be concentrated on the welded portion pressed by the welding pressing tool.

  Furthermore, in the method for manufacturing an assembled battery according to claim 5 of the present invention, since the welding pressing tool is disposed between a pair of electrodes and the connection fitting is welded to the unit cell, the connection bracket electrode is energized. The region can be efficiently welded by pressing with a welding pressing tool.

  Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a method for manufacturing an assembled battery for embodying the technical idea of the present invention, and the present invention does not specify the following method for manufacturing an assembled battery.

  Further, in this specification, for easy understanding of the scope of claims, numbers corresponding to the members shown in the embodiments are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  In the assembled battery of FIG. 3, a plurality of rechargeable unit cells 10 are connected in series via connection fittings 20 and connected in a straight line. A plurality of assembled batteries having this structure are connected in series to be used mainly in an electric vehicle such as a hybrid car. However, the assembled battery of the present invention can be used for applications other than electric vehicles and for which high output is required. In the battery pack shown in the figure, unit cells 10 that are cylindrical batteries are connected in a straight line. However, the assembled battery can also be connected in series by linearly connecting the unit cells, which are square batteries.

  As the unit cell 10, any rechargeable battery such as a nickel metal hydride battery, a lithium ion battery, or a nickel cadmium battery can be used. However, nickel-metal hydride batteries and lithium ion batteries are suitable for the unit cells used for the assembled batteries for electric vehicles. It is because the output with respect to a volume and a weight is large and it has the outstanding large current characteristic.

  As shown in the cross-sectional view of FIG. 4, the cylindrical battery that is the unit cell 10 hermetically seals the opening of the outer can 11 with a sealing plate 12 having a convex electrode 13. The outer can 11 and the sealing plate 12 are metal plates. The outer can 11 is manufactured by press-molding a metal plate into a cylindrical shape with a bottom. The sealing plate 12 is provided with a convex electrode 13 in the center. An electrode (not shown) is built in the outer can 11. Furthermore, the electrolytic solution is also filled. The outer can 11 has a sealing plate 12 hermetically fixed by caulking the end of the opening. The sealing plate 12 is sandwiched between the caulked portions of the outer can 11 via the gasket 14 and is hermetically fixed. The gasket 14 is an insulating rubber-like elastic body that insulates the sealing plate 12 and the outer can 11 and airtightly closes the gap between the sealing plate 12 and the outer can 11. In the unit cell 10 having this structure, a ring groove 15 is provided along the periphery at an end portion where the sealing plate 12 is provided in order to crimp the sealing plate 12 and sandwich it. Further, crimping ridges 16 are provided on the periphery of the sealing plate 12. This unit cell 10 has a sealing plate 12 as a first electrode and an outer can 11 as a second electrode. The nickel metal hydride battery uses a first electrode as a positive electrode and a second electrode as a negative electrode. The unit cell can also have the first electrode as a negative electrode and the second electrode as a positive electrode.

  As shown in the cross-sectional view of FIG. 4 and the exploded perspective view of FIG. 5, the assembled battery includes a connection fitting 20 that electrically connects the unit cells 10 between the end surfaces of the unit cells 10 that are linearly coupled, An insulating material 30 for arranging the connection fitting 20 at a fixed position is provided. The assembled battery shown in the figure includes a first electrode 19A that is a sealing plate 12 of one lower unit cell 10 in the figure and a second electrode that is the bottom of an outer can 11 of the other unit cell 10 that is on the upper side. 19B is connected to the connecting bracket 20. Since the unit cell 10 uses the sealing plate 12 and the outer can 11 as positive and negative electrodes, a short circuit occurs when the connection fitting 20 connected to the sealing plate 12 contacts the caulking ridge 16 that is a part of the outer can 11. In the assembled battery shown in the cross-sectional view of FIG. 4, the connection fitting 20 and the crimping ridge 16 are insulated by an insulating material 30.

  The connection fitting 20 is manufactured by press-molding a metal plate. The connection fitting 20 is provided with metal plating layers on both surfaces of a base metal plate such as an iron plate. The metal plating layer is composed of a conductive plating layer having excellent electrical conductivity and a small electrical resistance, and a resistance plating layer suitable for welding laminated on the surface of the conductive plating layer. The conductive plating layer is copper, silver, or an alloy thereof, and is a plating layer having a lower electrical resistance than the base metal plate and the resistance plating layer. The resistance plating layer is nickel, chrome, or an alloy thereof, and is a plating layer having an electric resistance higher than that of the conductive plating layer. The connection fitting 20 is likely to generate heat in the resistance plating layer and is quickly welded to the electrode 19 of the unit cell 10. Moreover, the electric resistance is small due to the conductive plating layer, and the unit cells 10 can be connected in series in a low resistance state.

  The connection fitting 20 is welded and connected to the electrodes 19 of the unit cells 10 disposed adjacent to each other so as to face each other, and the adjacent unit cells 10 are electrically connected in series. 4 and 5 includes a first welding portion 23A welded to the sealing plate 12 which is the first electrode 19A of one unit cell 10 on the lower side in the figure, and the first welding. 2nd welding part 23B which is outside the part 23A and is welded to the bottom part of the outer can 11 which is the second electrode 19B of the other unit cell 10. Hereinafter, in the drawing for connecting the connection fitting 20, the unit cell (the unit cell below in FIGS. 4 and 5) to which the first welded portion 23A is connected is referred to as the first unit cell 10A and the second welded portion 23B. Is a second unit cell 10B (a unit cell on the top in FIGS. 4 and 5).

  The connecting fitting 20 shown in the drawing is formed by pressing a metal plate into a ring shape with a hole, provided with a first welded portion 23A on the inner side, and provided with a second welded portion 23B on the outer side. 23 A of 1st weld parts and the 2nd weld part 23B are welded to the electrode 19 of the unit cell 10 which opposes, and the unit cell 10 arrange | positioned adjacently is connected in series. Further, the connecting fitting 20 shown in the figure has a central hole 24 in which the convex electrode 13 is disposed. The connection fitting can also be shaped to project the portion that guides the convex electrode without opening the center hole.

  4 and 5 presses a metal plate so that a cylindrical body portion 22 serving as a second welded portion 23B is provided on the outer periphery of the disc portion 21 provided with the first welded portion 23A. Processing. The disk portion 21 is provided with a first welded portion 23A around the center hole 24 and an energized portion 25 outside the first welded portion 23A. The first welded portion 23A and the energized portion 25 are pressed into a stepped shape so that the first welded portion 23A protrudes from the energized portion 25. As shown in FIG. 4, the connection fitting 20 is configured such that the current-carrying portion 25 is welded to the sealing plate 12 of the first unit cell 10 </ b> A while the first welded portion 23 </ b> A is welded to the outer can 11 of the first unit cell 10 </ b> A. The insulating material 30 is disposed between the energizing portion 25 and the crimping ridges 16 apart from the crimping ridges 16. The insulating material 30 insulates the current-carrying portion 25 of the connection fitting 20 and the caulking ridge 16 and prevents the current-carrying portion 25 from shorting to the caulking ridge 16.

  The connection fitting 20 can be welded to the first and second welded portions 23A and 23B by providing a plurality of welded convex portions 23a and 23b for welding to the first welded portion 23A and the second welded portion 23B, respectively. The welding convex portion 23a of the first welding portion 23A protrudes in the direction of the sealing plate 12 of the first unit cell 10A and is welded to the sealing plate 12 that is the first electrode 19A. The welding convex part 23b of the 2nd welding part 23B protrudes toward the surface of the exterior can 11 of the 1st unit cell 10B, and is welded to the bottom part of the exterior can 11 which is the 2nd electrode 19B. The connection fitting 20 shown in the plan view of FIG. 6 is provided with four welding projections 23a on the first welding portion 23A and eight welding projections 23b on the second welding portion 23B.

  In the connection fitting 20 of FIG. 6, a cutout portion 26 is provided in the first welded portion 23A, and the first welded portion 23A is divided into a plurality of pieces. The cutout portion 26 of the first welded portion 23A is provided so as to extend in the radial direction from the center hole 24 of the first welded portion 23A. The first welded portion 23A in the figure is divided into four parts by providing cutouts 26 at four locations at equal intervals, and a welded convex part 23a is provided at each divided part. That is, the first welded portion 23A is provided with welded convex portions 23a at equal intervals with a 90-degree pitch. Each of the four weld projections 23a provided on the first weld 23A is arranged concentrically.

  Further, in the connection fitting 20 of FIGS. 5 and 6, the second welded portion 23B is also provided with a notch 27 to divide the second welded portion 23B into a plurality of parts. The cutout portion 27 of the second welded portion 23B is provided so as to extend in the axial direction of the tubular cylindrical body portion 22, and has a shape formed by bending the middle into a V shape. The second welded portion 23B shown in the figure is also divided into four parts by providing cutout portions 27 at equal intervals at a pitch of 90 degrees. The cutout portion 27 of the second welded portion 23B is provided so as to be positioned between the cutout portions 26 provided in the first welded portion 23A. That is, the connection fitting 20 is provided with the cutout portion 26 of the first welded portion 23A and the cutout portion 27 of the second welded portion 23B that are displaced from each other. The second welded portion 23 </ b> B is provided with welded convex portions 23 b at both ends of each divided portion divided by the notch portion 27.

  The insulating material 30 is entirely formed of a rubber-like elastic body having insulating characteristics. The insulating material 30 has the outer periphery insulating part 31 which covers the outer peripheral surface of the unit cell 10 connected in series with each other. The outer peripheral insulating portion 31 of the insulating material 30 shown in the cross-sectional view of FIG. 4 has a cylindrical shape into which the end of the unit cell 10 is inserted. The cylindrical outer peripheral insulating portion 31 has a cylindrical shape into which the end portion of the first unit cell 10A is inserted. The cylindrical part which is the outer periphery insulating part 31 has the inner shape as the outer shape of the unit cell 10 so that the end of the unit cell 10 can be inserted and connected to a fixed position. The insulating material formed of a rubber-like elastic body that is elastically deformed makes the inner diameter of the cylindrical portion of the outer peripheral insulating portion smaller than the outer diameter of the unit cell, and elastically expands in a state where the end of the unit cell is inserted. It can also be in a state.

  Furthermore, the insulating material 30 in FIG. 4 protrudes from the inner surface of the cylindrical outer peripheral insulating portion 31 and is provided with a retaining stopper 35. The retaining stopper 35 is guided by the ring groove 15 provided on the outer periphery of the first unit cell 10A. The insulating material 30 can be connected so that the first unit cell 10 </ b> A is inserted into the cylindrical outer peripheral insulating portion 31 and the retaining stopper 35 is inserted into the ring groove 15 so that it is difficult to be removed.

  Further, the insulating material 30 in FIGS. 4 and 5 is provided so that the insulating ring 32 protrudes inside in order to prevent the connection fitting 20 from short-circuiting with the outer can 11 of the first unit cell 10A. . The insulating ring 32 is on the surface of the crimping ridge 16 of the first unit cell 10 </ b> A and insulates the surface of the crimping projection 16. The energizing portion 25 of the connection fitting 20 is disposed on the upper surface of the insulating ring 32 and is insulated from the caulking ridge 16 of the first unit cell 10A. Furthermore, a ring ridge 34 that covers the inner surface of the crimping ridge 16 is integrally formed on the inner peripheral edge of the insulating ring 32. The ring ridge 34 is shaped to be fitted inside the caulking ridge 16. This insulating material 30 is disposed at a fixed position at the end of the first unit cell 10 </ b> A with the ring ridge 34 inserted inside the caulking ridge 16.

The above assembled battery connects opposing unit cells 10 in series in the following steps.
(1) The insulating material 30 is set on the first unit cell 10 </ b> A, and the connection fitting 20 is set on the insulating material 30. In this state, the end on the first electrode side of the first unit cell 10 </ b> A is inserted into the outer peripheral insulating portion 31 of the insulating material 30. The insulating ring 32 of the insulating material 30 insulates the caulking ridge 16 of the first unit cell 10 </ b> A and the energizing portion 25 of the connection fitting 20.

(2) As shown in FIGS. 7 and 8, the pair of welding pressing tools 40 are pressed against the first welding portion 23A. The welding pressing tool 40 presses the welding convex portion 23 a provided in the first welding portion 23 </ b> A against the sealing plate 12 of the unit cell 10. Further, the electrode 50 is brought into contact with the energization part 25 of the connection fitting 20. The connection fitting 20 presses the welding convex part 23a provided in the first welding part 23A as the welding point 28 with the welding pressing tool 40, and is a part different from the welding point 28, outside the first welding part 23A. The electrode 50 is brought into contact with the energizing portion 25 as the electrode contact portion 29. In this state, a welding current is passed through the electrode 50 as shown by a thick line in FIG. 8 to weld the first welded portion 23A to the sealing plate 12 of the first unit cell 10A. The connection fitting 20 is energized from the electrode 50 and welds the first welding portion 23 </ b> A pressed by the welding pressing tool 40 to the unit cell 10.

  The welding pressing tool 40 presses the connection fitting 20 with a stronger force than the electrode 50 and welds the welded portion 23 of the connection fitting 20 to the unit cell 10. The connection fitting 20 supplies a welding current from the electrode 50 to weld the welded portion 23 pressed by the welding pressing tool 40 to the unit cell 10. Therefore, the welding pressing tool 40 presses the connection fitting 20 with a stronger force than the electrode 50 that supplies the welding current to the connection fitting 20 to weld the welded portion 23 to the unit cell 10. For example, the pressing force of the welding pressing tool 40 is 2 to 20 times the pressing force of the electrode 50. However, the pressing force of the welding pressing tool varies depending on the material and thickness of the connection fitting, and the shape and number of welding projections, and the pressing force of the electrode changes depending on the contact area with the fitting and the welding current. The pressing force of the welding pressing tool and the electrode is set to an optimum value in consideration of various conditions.

  In the above welding method, the insulating material 30 that insulates the caulking ridge 16 on the outer peripheral portion of the unit cell 10 is disposed between the unit cells 10 that are linearly connected. The current-carrying portion 25 of the connection fitting 20 is insulated from the ten crimping ridges 16. The electrode 50 is brought into contact with the surface of the current-carrying portion 25 of the connection fitting 20 insulated by the insulating material 30 to supply a welding current to the connection fitting 20, and the welding portion 23 pressed by the welding pressing tool 40 is welded. In this method, the current-carrying portion 25 that contacts the electrode 50 is insulated from the unit cell 10. For this reason, the energization part 25 of the connection fitting 20 with which the electrode 50 is contacted is not welded to the unit cell 10, and the welding part 23 pressed by the welding pressing tool 40 can be reliably welded. In addition, since the current-carrying portion 25 pressed by the electrode 50 is not welded, the adverse effect due to the welding heat of the electrode 50 can be eliminated, and the life of the electrode 50 can be particularly prolonged.

  Further, in the above welding method, the welding pressing tool 40 is disposed between the pair of electrodes 50 to weld the connection fitting 20 to the unit cell 10. In this method, as shown by a thick line and an arrow in FIG. 8, the connection fitting 20 can be energized with a pair of electrodes 50, and a region to be energized can be pressed with a welding pressing tool 40 to be welded. For this reason, there exists the characteristic which can weld the welding part 23 reliably with the welding press tool 40. FIG.

  The welding pressing tool 40 of FIG. 7 and FIG. 8 consists of a pair of rods, presses the welding part 23 with the tip of the rod, and welds it to the unit cell 10. The pair of rods are fixed to a reciprocating table (not shown) that moves toward and away from the welded portion 23 and presses the welded portion 23 together. The welding pressing tool 40 presses and welds the welded portion 23 and radiates welding heat generated during welding. The welding pressing tool 40 is made of metal and can efficiently cool the welding heat of the welded portion 23. This is because the metal conducts welding heat efficiently and dissipates heat. The rod made of metal for the welding pressing tool 40 is connected to the reciprocating table with the tip insulated or insulated. With this structure, the pair of metal rods can shorten the welding current, and the welding failure due to the welding current bypass can be eliminated. However, the welding pressing tool does not necessarily need to be metallic, and can be made of a heat-resistant material such as ceramics.

(3) After welding the first welded portion 23A to the sealing plate 12 that is the first electrode 19A of the first unit cell 10A, the lower end portion of the second unit cell 10B is connected to the cylindrical portion of the connection fitting 20. 22 is inserted. The second unit cell 10B is inserted into the cylindrical body portion 22 and connected to the second welding portion 23B. In this state, the second welded portion 23 of the connection fitting 20 is brought into contact with the bottom of the outer can 11 of the second unit cell 10B.

(4) As shown in FIGS. 9 and 10, the second welding portion 23 </ b> B of the connection fitting 20 is pressed with the welding pressing tool 40, and the electrode 50 is brought into contact with the outside of the welding pressing tool 40. In other words, the welding pressing tool 40 is set between the pair of electrodes 50, and the welding convex portion 23b that becomes the welding point 28 is pressed against the surface of the outer can 11 of the second unit cell 10B. The pair of welding pressing tools 40 press the welding projections 23b of the second welding portion 23B so as to straddle the notching portions 27, that is, so as to arrange the notching portions 27 between the pair of welding pressing tools 40. The electrode 50 is a surface of the cylindrical body portion 22 which is the second welded portion 23B, and a portion different from the welding point 28 is used as an electrode contact portion 29, that is, a second welded portion in which the welded convex portion 23a is not provided. Contact the surface of 23B. In this state, a welding current is supplied from the electrode 50 to the connection fitting 20, and the second welded portion 23B is welded to the bottom of the outer can 11 of the second unit cell 10B.

  In this welding process, the welding press tool 40 and the electrode 50 are the same as those used to weld the first welded portion 23A to the first unit cell 10A. That is, the welding pressing tool 40 is made of metal to efficiently cool the welded portion 23, the metal welding pressing tool 40 is insulated and connected to a reciprocating motion table (not shown) to prevent a short current, and further welding While making the pressing force of the pressing tool 40 stronger than the pressing force of the electrode 50, the welding pressing tool 40 is set between the pair of electrodes 50 to reliably weld the welded portion 23.

  Further, in the step of welding the second welded portion 23B to the outer can 11 of the second unit cell 10B, as shown in FIG. 11, the electrode which is the inner surface of the second welded portion 23B and contacts the electrode 50 An insulating material 39 is disposed on the inner surface of the contact portion 29 so that the insulating material 39 can insulate the electrode contact portion 29 of the second welded portion 23 </ b> B from the outer can 11. In this state, when a welding current is supplied from the electrode 50 to the second welding portion 23B, the welding current does not flow in the bypass path indicated by the chain line in FIG. 11 but flows in the path indicated by the thick line in FIG. The welding projection 23b is reliably welded to the outer can 11.

It is an expanded sectional view which shows the connection structure of the conventional battery module. It is a perspective view which shows the connection metal fitting of the battery module of FIG. It is a perspective view which shows an example of the assembled battery manufactured with the manufacturing method concerning one Example of this invention. It is an expanded sectional view which shows the connection structure of the unit cell of the assembled battery shown in FIG. 3, and a connection metal fitting. It is a disassembled perspective view of the assembled battery shown in FIG. It is a top view of a connection metal fitting. It is a perspective view which shows the state which welds a connection metal fitting to a 1st unit cell. It is an expanded sectional view which shows the state which welds a connection metal fitting to a 1st unit cell. It is a perspective view which shows the state which welds a connection metal fitting to a 2nd unit cell. It is an expanded sectional view which shows the state which welds a connection metal fitting to a 2nd unit cell. It is an expanded sectional view which shows another example which welds a connection metal fitting to a 2nd unit cell.

Explanation of symbols

10: Unit cell 10A: First unit cell
DESCRIPTION OF SYMBOLS 10B ... 2nd unit cell 11 ... Exterior can 12 ... Sealing plate 13 ... Convex part electrode 14 ... Gasket 15 ... Ring groove 16 ... Caulking protrusion 19 ... Electrode 19A ... 1st electrode
19B ... 2nd electrode 20 ... Connection metal fitting 21 ... Disk part 22 ... Cylindrical body part 23 ... Welding part 23A ... 1st welding part
23a ... welding convex part
23B ... second weld
23b ... weld convex part 24 ... center hole 25 ... energizing part 26 ... notch part 27 ... notch part 28 ... welding point 29 ... electrode contact part 30 ... insulating material 31 ... outer periphery insulating part 32 ... insulating ring 34 ... ring convex strip 35 ... Stop stopper 39 ... Insulating material 40 ... Welding pressing tool 50 ... Electrode 80 ... Connection fitting 81 ... First welded portion 82 ... Second welded portion 83 ... Disc 84 ... Cylindrical portion 90 ... Unit cell 91 ... Exterior can 92 ... Sealing Board

Claims (5)

A method of manufacturing an assembled battery in which a connection fitting (20) is spot welded to an electrode (19) of an adjacent unit cell (10), and a plurality of unit cells (10) are connected via the connection fitting (20). ,
The welded portion (23) of the connection fitting (20) is pressed to the surface of the unit cell (10) with a welding pressing tool (40), and the surface of the connection fitting (20) is different from the welding point (28). A pair of electrodes (50) in contact with each other, the welding current is passed through the connection fitting (20) with the pair of electrodes (50), and the welding current supplied to the connection fitting (20) is welded and pressed. The electrode (19) of the unit cell (10) is energized by the welded part (23) pressed by the tool (40), and the welded part (23) of the connection fitting (20) is connected to the electrode of the unit cell (10) ( 19) A method for manufacturing an assembled battery by spot welding.   The unit cells (10) are arranged in a straight line, a connection fitting (20) is arranged between the unit cells (10), and the first welded portion (23A) of the connection fitting (20) is connected to one unit cell. The assembled battery according to claim 1, wherein the second unit cell (10) is connected in series by welding the second welded part (23B) to the other unit cell (10). Production method.   The unit cell (10) to be connected by the connection fitting (20) is a cylindrical battery in which the opening of the outer can (11) is closed by the sealing plate (12), and the one unit cell (10) is a cylinder. The first welded portion (23A) of the connection fitting (20) is welded to the sealing plate (12) of the battery, and the second unit cell (10) is connected to the bottom of the outer casing (11) of the cylindrical battery. The method for manufacturing an assembled battery according to claim 2, wherein the two welds (23 B) are welded.   An insulating material (30) that insulates the outer periphery of the unit cell (10) is disposed between the unit cells (10) connected in a straight line, and is insulated from the unit cell (10) by the insulating material (30). The method for manufacturing an assembled battery according to claim 1, wherein the electrode (50) is brought into contact with the surface of the connection fitting (20) to be welded to weld the welded portion (23).   The method for manufacturing an assembled battery according to claim 1, wherein the welding pressing tool (40) is disposed between the pair of electrodes (50), and the connection fitting (20) is welded to the unit cell (10).

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