JP2011253683A - Connection method of connection member for battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance weld quality and maintainability of a welder in connection method of a connection member for battery pack where connection members that connect multiple batteries electrically are connected using a welder.SOLUTION: The connection method of a connection member includes a step of pressing one side of a connection member 11B in the direction of the external terminal of a battery 11A using a pair of roller electrodes 10 and 10, a step of connecting the other side of the connection member 11B to the external terminal of the battery 11A by supplying a current between the pair of roller electrodes 10 and 10, and a step of touching the pair of roller electrodes 10 and 10 to the connection member 11B and rolling the pair of roller electrodes 10 and 10 by changing the relative position of the pair of roller electrodes 10 and 10 and the connection member 11B. The pair of roller electrodes 10 and 10 are touched to the connection member 11B and rolled after stopping current supply before the pair of roller electrodes 10 and 10 are separated from the connection member 11B in a nonconduction state.

Description

  The present invention relates to a connection method between a connection member and an external terminal of a battery when connecting external terminals of the battery with a connection member to form an assembled battery which is an assembly of single cells.

  In recent years, cordless and portable computers such as AV devices and personal computers have been rapidly promoted, and secondary batteries represented by lithium ion batteries and the like are widely used as driving power sources widely used in these devices. . And most of these batteries are electrically connected in series or in parallel between the electrodes of a single battery (unit cell) housed in a cylindrical container with a positive electrode and a negative electrode at both ends. It is used in the form of an assembled battery by being housed or covered with an exterior insulating tube.

This will be described with reference to FIG. In FIG. 7, reference numerals 51 </ b> A and 51 </ b> B denote single cells, and one single cell 51 </ b> A is parallel to the radial direction with the external terminal of the positive electrode facing upward, and the other single battery 51 </ b> B is facing the external terminal of the positive electrode downward. Are arranged as follows. And the connection member 52 is arrange | positioned ranging over the external terminal of the positive electrode of the cell 51A, and the external terminal of the negative electrode of the cell 51B. The connection member 52 is generally called a tag or a bus bar, and a ribbon-like (thin plate-like) member made of a conductor is used. And the vicinity of the both ends of this connection member 52 is connected with the external terminal of both unit cell 51A, 51B by welding, respectively.

  In general, resistance welding is used for this welding. As shown in FIG. 8, the connecting member 52 is placed on the unit cell 51A and a pair of electrode rods 53A and 53B are brought into contact with each other from above. Let A current is passed between both electrodes while applying a predetermined pressing force to the upper surface of the connection member 52 at the tips of the pair of electrode bars 53A and 53B. By doing in this way, the said electric current will flow through the two flow paths shown in FIG.

  When the current flows, self-heating due to Joule heat is generated in the objects to be joined, and contact points C and D between the external terminal of the unit cell 51A and the connection member 52 exist on the flow path in the figure. Therefore, heat is generated by contact resistance at these contact points. The contact points C and D are melted to form a nugget and welding is performed. On the other hand, since the flow path A only flows through the connecting member 52, it hardly contributes to the formation of the nugget. Rather, if the current of the flow path A is relatively larger than the current of the flow path A, it is a waste current. As a result, the quality of welding may be hindered.

  Therefore, there is a device for reducing the waste current by providing the connection member 52 with a slit 54 as shown in FIG. 10, but this also has a limited effect because of the wraparound current. Furthermore, in the technique described in Patent Document 1, as shown in FIG. 11, two independent conductive members 55A and 55B are spaced apart and arranged in parallel, and these conductive members 55A and 55B are insulated holding film 56. The electrode rods 53A and 53B are brought into contact with the conductive members 55A and 55B exposed at the openings provided in the holding film 56 so that current flows.

JP 2004-171898 A (page 11, FIGS. 1 to 3)

  However, it is not an application that requires a large current, such as an electric vehicle or an electric motorcycle, but is intended for connection between terminals of an assembled battery for a relatively small current application such as a portable device. That is, it is possible to use a thin ribbon-like material that is not subjected to processing other than cutting of the outer shape, and a material having a larger electric resistance than copper or aluminum can be selected as the material, such as nickel. In such a case, the adverse effect of the current flowing in the flow path A (FIG. 9), which is the above-described waste current, is in an acceptable range. It becomes a big subject that dispersion | variation generate | occur | produces in welding conditions because the residue of 52 adheres.

  In addition, when the welding rods 53A and 53B are separated from the welding location after the thin ribbon-like connection member 52 is welded, the phenomenon that the tip of the welding rod is welded to the connection member 52 and the welded portion is peeled off as a result is a big problem. It has become. Therefore, the present invention reduces the maintenance work required for dressing (cleaning) of the welding electrode and solves the problems as described above, and prevents the connection member, which is an object to be welded, from being welded (attached) to the welding electrode. Therefore, the purpose is to improve the bonding quality.

The present invention provides, as a first aspect, a connection method for a connection member for an assembled battery in which a connection member for electrically connecting a plurality of batteries is connected using a welding machine, and a pair of roller electrodes provided in the welding machine A step of interposing a ribbon-shaped connecting member between the battery and the external terminal of the battery, pressing one surface of the connecting member toward the external terminal of the battery with the pair of roller electrodes, and the pair of roller electrodes Passing a current between them, connecting the other surface of the connecting member to the external terminal of the battery, and changing the relative positions of the pair of roller electrodes and the connecting member, A step of rolling contact with the connecting member, and after the current is stopped and before the pair of roller electrodes are separated from the connecting member, the pair of roller electrodes are connected in the non-energized state. Rolling contact with member It provides a method of connecting the assembled battery connecting member, wherein.

Thereby, even if a roller electrode and a connection member weld by flowing welding current, welding can be avoided by carrying out rolling contact in the non-energized state before separating a roller electrode from a connection member. Therefore, when the roller electrode is subsequently separated from the connection member, the force for peeling the connection member from the external electrode of the battery does not work. Further, since the entire outer peripheral surface of the electrode can be used as a contact surface with the connection member, the adhesion of the oxide film or the residue of the connection member that is dirt on the electrode is not concentrated in one place, and the frequency of maintenance is reduced.

As a second aspect of the present invention, energization of the current is started after the pair of roller electrodes starts rolling contact with the connecting member, and the energization is stopped before the rolling contact is stopped. The connection method of the connection member for assembled batteries as described in the 1st aspect characterized by this is provided.

  Accordingly, since the welding current flows only while the contact portion between the electrode and the connection member is reliably moved, the possibility of the occurrence of welding is further reduced.

According to a third aspect of the present invention, as the third aspect, the pair of roller electrodes are brought into rolling contact with the connecting member, and the current is supplied to the pair of roller electrodes. A method for connecting an assembled battery connecting member according to a first aspect is provided, wherein the pair of roller electrodes are rolled in a non-energized state in a direction opposite to the direction in which the roll contacts.

Thereby, even if the position where the welding is finished and the current is stopped is the end of the connecting member, the electrode is separated from the connecting member after reliably avoiding welding by rolling the roller electrode in the reverse direction. be able to.

According to a fourth aspect of the present invention, there is provided the battery pack connecting member according to any one of the first to third aspects, wherein a ribbon-shaped member made of nickel is used as the connecting member. Provide a connection method.

Thereby, the stable welding quality by the raw material of suitable electrical resistance is obtained, and since it is a raw material excellent in corrosion resistance, the reliability after it completes as an assembled battery is securable. Furthermore, since it is a simple ribbon-like member and does not require processing such as drilling, pressing, and bonding, it can be used as a joining member by simply pulling it out from the wound storage form and simply cutting it. Therefore, the cost is low and the mass productivity is excellent.

Furthermore, the present invention provides, as a fifth aspect, a method for connecting an assembled battery connecting member according to any one of the first to fourth aspects, wherein the polarity of the current is switched while the current is flowing. I will provide a.

Thereby, since the polarity effect resulting from the direction of an electric current can be reduced, connection reliability improves.

As described above, in the conventional electrode rod, the contact portion with the connecting member is only the tip surface of the rod-like electrode, and therefore, deposits such as oxide film and residue of the connecting member must be frequently removed. Since this so-called dressing operation involves a polishing operation, it is not only labor-intensive, but also wears the electrode, shortening the life of the electrode itself. By replacing the electrode with a roller electrode, the frequency of dressing work, that is, maintenance, is greatly reduced, and the life of the electrode is extended.

When the roller electrode is used, welding can be performed while rotating the electrode, in other words, changing the contact position between the electrode and the connecting member. On the other hand, when the conventional electrode rod is used, the contact portion may be overheated and the electrode and the connection member may be welded by continuing to contact the connection member at a certain position while the welding current is applied. High nature. Further, even when the roller electrode and the connection member are welded, welding can be avoided by performing rolling contact in a non-energized state thereafter. Therefore, according to the present invention, when the welding process is completed and the electrode is retracted from the welded part, the welded part is not destroyed, the welding quality is stabilized and the yield of the welding process is improved.

Schematic of a welding apparatus showing an embodiment of the present invention Partial detail drawing which shows embodiment of this invention The principal part perspective view of embodiment of this invention The schematic diagram which shows other 1st Embodiment of this invention. Schematic diagram showing another second embodiment of the present invention The schematic diagram which shows other 3rd Embodiment of this invention. Perspective view showing conventional technology Perspective view showing conventional technology Sectional view showing conventional technology Perspective view showing conventional technology Perspective view showing conventional technology

Next, an embodiment of a connection method for an assembled battery connection member according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the overall configuration of a welding machine used in the present embodiment. This welding machine manually conveys and positions an object to be welded (hereinafter referred to as a workpiece), and will be described below based on this manual system apparatus. In FIG. 1, reference numeral 1 is a welding machine, 2 is a control unit, and 3 is a power supply unit. Reference numeral 4 is a base, 5 is a column erected from the base 4, 6 is an elevating part held up and down by the column 5, and 7 and 7 can be moved up and down independently of the elevating part 6. A pair of held electrode holders, 8 and 8 are a pair of insulating blocks fixed to the electrode holders 7 and 7, respectively, 9 and 9 are power supply blocks fixed to the insulating blocks 8 and 8, and 10 and 10 are power supply blocks A pair of roller electrodes 9 and 9 are rotatably held.

The roller electrodes 10 and 10 held by the power supply blocks 9 and 9 move up and down integrally with the electrode holders 7 and 7 while being electrically insulated from the electrode holders 7 and 7 through the insulating blocks 8 and 8. It is. Further, the elevating unit 6 can be moved up and down with respect to the support column 5 by driving the first actuator 6 </ b> A, and the pair of roller electrodes 10, 10 is moved toward or away from the work 11 by moving up and down. The workpiece 11 is placed on the stage 12, and the stage 12 moves in the direction of arrow O by the drive of the second actuator 12A. Here, the direction of the arrow O coincides with the rotation direction of the roller electrodes 10 and 10.

Next, a rotatable holding structure for the pair of roller electrodes 10 and 10 is shown in FIG. FIG. 2 shows a symmetric roller electrode holding structure. The right side of the figure is shown in a cross-sectional view and will be described with reference numerals attached to the right side. The roller electrode 10 is fixed to one end of a conductive shaft 13, and the conductive shaft 13 is inserted into a through hole provided in the power supply block 9. In addition, conductive grease is filled between the inner surface of the through hole and the conductive shaft 13 and is held rotatably while ensuring the conductivity of both. Here, the small-diameter portion 13A of the conductive shaft 13 is a grease reservoir for conductive grease.

1 is connected to the power supply blocks 9 and 9, current flows between the roller electrodes 10 and 10 via the conductive shafts 13 and 13 during welding. As shown in FIG. 2, both roller electrodes 10 and 10 are arranged in a direction facing each other with a gap indicated by reference numeral, and are provided so that the directions of the rotation axes thereof coincide with each other. The outer peripheral surface 10 </ b> A of the 10 largest outer diameter portions is in contact with the workpiece 11.

Next, the operation of the welding machine 1 shown in FIG. 1 will be described. After the workpiece 11 is positioned and placed on the stage 12, the operation of the control unit 2 is started. The control unit 2 moves the stage 12 in the direction of arrow E and positions it at a predetermined position, that is, a position where the starting point of the welded portion of the workpiece 11 is directly below the pair of roller electrodes 10 and 10. Next, when the elevating part 6 is lowered, the pair of roller electrodes 10 and 10 are also lowered together with this, and the outer peripheral surface 10 </ b> A of the roller electrodes 10 and 10 comes into contact with the welded portion of the work 11. Thereafter, the elevating unit 6 continues to descend, but the electrode holders 7 and 7 integrated with the roller electrodes 10 and 10 stop descending.

Thereby, when the relative position of the raising / lowering part 6 and the electrode holders 7 and 7 changes in the up-and-down direction, and the roller electrodes 10 and 10 press the welding location with a predetermined pressing force, they are built in the raising / lowering part 6. The contact of a micro switch (not shown) is switched. Here, since the electrode holders 7 and 7 are structured to move up and down independently with respect to the elevating part 6, there is a difference in the vertical position between the two welding locations where the pair of roller electrodes 10 and 10 abut each other. Even in some cases, the two portions can be brought into contact with each other with an equal pressing force. Further, the surface of the workpiece 11 is changed in a state where the relative positions of the roller electrodes 10 and 10 and the workpiece 11 are changed and the roller electrode is rotating, in other words, in a state where the roller electrodes 10 and 10 are in contact with the workpiece 11. Even if there are slight irregularities, the irregularities can be absorbed by the independent vertical movements of the electrode holders 7 and 7 to maintain a predetermined pressing force. In this way, the control unit 2 that has received the contact switching signal of the microswitch recognizes that the roller electrodes 10 and 10 are in contact with the starting point of the welding location of the workpiece 11 with a predetermined pressing force.

Next, the control unit 2 controls the movement of the stage 12 and the current output of the power supply unit 3. FIG. 3 shows this state. A connection member 11B is placed on the external electrode of the unit cell 11A constituting the workpiece 11, and the roller electrodes 10 and 10 are energized while rolling on the connection member 11B. It shows a state. At this time, since the workpiece 11 has moved in the direction of the arrow K, the pair of roller electrodes 10 and 10 rotate in the direction of the arrow K. The current flows from one of the pair of roller electrodes 10, 10 to the other via the connection member 11B and the external electrode of the unit cell 11A, and forms a nugget at the contact point between the connection member 11B and the external electrode of the unit cell 11A. Welding is done.

At this time, the power supply for supplying the current is preferably a pulse heat power supply that instantaneously outputs a large current in a pulse shape. In addition, the current can be in one direction, but the polarity can be switched every few milliseconds during energization in order to reduce polarity effects such as differences in heat generation on both electrodes depending on the current direction. More preferably, the power source is of the type. In addition, the direction in which the pair of roller electrodes 10 and 10 are in rolling contact with each other is the width direction of the ribbon-like connecting member 11B in FIG. 3, but this may be the longitudinal direction of the connecting member 11B. In the case of having a large area, if the roller electrode is rolled in the longitudinal direction, a welded portion longer than that in the case of rolling in the width direction can be obtained.

  Next, a first embodiment of the present invention will be described with reference to FIG. FIG. 4A shows the state of welding from the direction indicated by the arrow in FIG. 4A, reference numerals 101 and 102 indicate the positions of the roller electrodes 10 and 10, reference numeral 11A indicates a cross section of the external electrode of the workpiece 11, and 11B indicates a cross section of the connecting member in the width direction. In the first embodiment, first, a current is passed between the electrodes while the roller electrodes are stationary at a fixed position indicated by reference numeral 101. Next, after energization is stopped, the roller electrodes 10 and 10 are brought into rolling contact with the reference numeral 102 and then separated from the connection member 11B.

  The state of the workpiece as a result of welding by such a method is shown in FIG. FIG. 4B is a plan view of the welded portion, showing a region where the hatched portion surrounded by the solid line is welded, and the portion surrounded by the dotted line is not welded but is in contact with the roller electrode Indicates the area. In the first embodiment, two spot-like welds are formed as shown in FIG. 4B. In addition, the roller electrodes 10, 10 are energized between the electrodes, the energization is stopped, and the energization is stopped. Then, the roller electrodes 10, 10 are brought into contact with another position. Then, after stopping energization, the roller electrodes 10 and 10 are brought into rolling contact again and then separated from the connecting member 11B is shown in FIG. In this way, the number of spot-like welds can be increased.

  Next, a second embodiment of the present invention will be described with reference to FIG. Since the configurations of FIGS. 5A to 5C are the same as those in FIG. In the second embodiment, as shown in FIG. 5A, the roller electrodes 10 and 10 are first positioned at the position of reference numeral 111, and rolling contact is started without energization between the electrodes. When the roller electrodes 10 and 10 start rolling and reach the position indicated by reference numeral 112, current is applied between the electrodes, and the current continues to be transferred to the position indicated by reference numeral 113 together with the rolling contact. Next, energization is stopped at the position of reference numeral 113, but the rolling contact is continued until the position of reference numeral 114, and then separated from the connection member 11B.

  FIG. 5B shows the state of the workpiece as a result of welding by such a method. In FIG. 5 (b), two belt-shaped welds are generated as shown by being surrounded by a solid line and hatched. The regions surrounded by dotted lines at both ends of each welded portion are regions that are not welded but are in contact with the roller electrode. Further, by interrupting energization during the rolling, the welded portion can be divided as shown in FIG.

  Next, a third embodiment of the present invention will be described with reference to FIG. 6 (a) to 6 (c) are the same as those in FIG. In the third embodiment, as shown in FIG. 6A, first, the roller electrodes 10 and 10 are positioned at the position of reference numeral 121, energization is performed between the electrodes, and at the same time, rolling contact is started. Thereafter, the rolling contact is continued with energization. When the roller electrodes 10 and 10 reach the position of reference numeral 122, the energization is stopped and simultaneously the rolling contact is stopped. Next, the rolling contact is started from the position indicated by reference numeral 122 in the opposite direction to the previous direction while the energization is stopped. When the roller electrode reaches the position indicated by reference numeral 123, the rolling contact is stopped and separated from the connecting member 11B.

  FIG. 6B shows the state of the workpiece as a result of welding by such a method. In FIG. 6 (b), two belt-like welds are generated as shown by being surrounded by a solid line and hatched. In this case, a belt-like welded portion that is longer than the welded portion shown in FIG. 5B shown in the description of the second embodiment can be formed. In this embodiment, since the rolling contact is performed in the reverse direction after the energization between the electrodes of the roller electrodes 10 and 10 is stopped, the welded portion can be formed up to the vicinity of the end portion of the connecting member 11B. Also, energization between the electrodes is started at the same time as the rolling contact of the roller electrodes 10 and 10 and is not stopped at the same time as the rolling contact is stopped, but between the electrodes for a predetermined time in a stationary state before the rolling contact is started. 6, and after the rolling contact performed together with the energization is stopped and before the rolling contact is performed in the reverse direction, the belt-like welded portion is energized as shown in FIG. A nugget can be grown by applying a current to only both ends for a long time.

In this embodiment, the workpiece 11 is placed on the stage 12 and the stage 12 is moved to realize the rolling contact between the roller electrodes 10, 10. However, the roller electrodes 10, 10 and the workpiece 11 are realized. Therefore, it is needless to say that the same effect can be obtained as a structure of a welding machine that moves the roller electrodes 10 and 10 in the rolling direction. Similarly, the roller electrodes 10 and 10 may be brought into contact with or separated from the workpiece 11 by moving the workpiece 11 up and down. Further, the battery as the work 11 is not limited to a form in which external electrodes are provided at both ends of a cylindrical container, and can be applied to a rectangular container or a protruding plate electrode. .

DESCRIPTION OF SYMBOLS 1 Welder 2 Control part 3 Power supply part 4 Base 5 Strut 6 Lifting / lowering part 6A 1st actuator 7 Electrode holder 8 Insulation block 9 Feeding block 10 Roller electrode 11 Work 11A End battery 11B Connection member 12 Stage 12A 2nd actuator 13 Conductive shaft 14 Power supply cable

Claims (5)

A connecting method for a battery pack connecting member for connecting a connecting member for electrically connecting a plurality of batteries using a welding machine,
A ribbon-shaped connection member is interposed between a pair of roller electrodes provided in the welding machine and the external terminal of the battery, and one surface of the connection member is pressed toward the external terminal of the battery by the pair of roller electrodes. And a process of
Passing a current between the pair of roller electrodes and connecting the other surface of the connecting member to an external terminal of the battery;
Changing the relative positions of the pair of roller electrodes and the connection member, and rolling the pair of roller electrodes to the connection member;
After the current is stopped and before the pair of roller electrodes are separated from the connection member, the pair of roller electrodes are brought into rolling contact with the connection member in a non-energized state. Connection method of connecting members. The energization of the current is started after the pair of roller electrodes starts rolling contact with the connecting member, and the energization is stopped before the rolling contact is stopped. A method for connecting an assembled battery connecting member. After the pair of roller electrodes is brought into rolling contact with the connecting member and the current is passed, and the energization to the pair of roller electrodes is stopped, the direction opposite to the direction in which the pair of roller electrodes were in rolling contact during energization 2. The method for connecting a battery pack connecting member according to claim 1, wherein the pair of roller electrodes are in rolling contact with each other in a non-energized state. The method for connecting an assembled battery connecting member according to any one of claims 1 to 3, wherein a ribbon-like member made of nickel is used as the connecting member. 5. The connection method for a battery pack connection member according to claim 1, wherein the polarity of the current is switched while the current is flowing.

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