WO2006090511A1 - Manufacturing method of electrical device assembly - Google Patents

Abstract

A method for manufacturing a battery pack in which an electrode tab is not removed easily when electrode tabs led out from battery cells are welded, and the electrode tabs can be electrically connected with each other with high reliability. A battery cell (20) constituting the battery pack has electrode tabs (25a, 25b) for positive and negative electrodes led out from the sealed part of a packing film. The electrode tabs (25a, 25b) are partially overlapped while directing the forward ends vertically upward. Under the state where the electrode tabs (25a, 25b) are overlapped, the electrode tabs are melted partially from the forward end side, thereby being welded with each other.

Description

 Specification

 Method for manufacturing electrical device assembly

 Technical field

 The present invention relates to a method for manufacturing an electrical device assembly in which a plurality of electrical devices (for example, batteries and capacitors) having electrical device elements that store and output electrical energy are assembled. In particular, the present invention relates to a method of manufacturing an electric device assembly in which electrode tabs drawn out from the electric device caps are connected by welding.

 Background art

 In recent years, for example, as a driving power source for an electric vehicle, an assembled battery in which a plurality of battery cells are interconnected in series and Z or in parallel has been developed. The configuration of such an assembled battery will be briefly described with reference to FIG. The assembled battery 150 is a collection of a plurality of battery cells 120 (only two are shown in FIG. 1), and the electrode tabs 125a and 125b drawn from each battery cell 120 are electrically connected to each other! Speak. Note that the electrode tabs 125a and 125bi are all metallic materials, and the thickness thereof is relatively thin, for example, about 50 m to 300 m.

 [0003] Japanese Unexamined Patent Publication No. 2003-338275 discloses that the electrode tabs 125a and 125b are bonded to each other using, for example, ultrasonic welding or laser welding in the above-described configuration. This document also discloses that the electrode tab and the bus bar are electrically connected. Note that the bus bar is a long plate-shaped member made of a conductive metal material. One method of using the bus bar is to electrically connect the electrode tabs of the battery cells arranged away from each other, for example. To connect to.

 Disclosure of the invention

 Problems to be solved by the invention

[0004] However, although the above-mentioned Japanese Patent Application Laid-Open No. 2003-338275 discloses that the electrode tabs are joined to each other using laser welding or the like, the details of the welding process are described. It hasn't been done.

[0005] For example, the posture as shown in FIG. 1, that is, the electrode tabs 125a, 125b are in the horizontal direction. If laser welding or the like is performed in an extended posture, the following problems may occur. That is, for example, when a laser is irradiated from the upper surface side to the electrode tab 125a, there is a possibility that the molten member may be pulled out vertically depending on the irradiation intensity of the laser. When the member is detached, the joint strength at the joint between the electrode tabs is lowered, and the reliability of the electrical connection is also lowered. In particular, as described above, since the electrode tabs 125a and 125b also have a thin member force, it is considered that such a problem of member removal is relatively likely to occur.

 [0006] The force described above taking the battery cell 120 functioning as a battery as an example. The above problems are not limited to batteries, and when manufacturing an electrical device assembly that requires electrode tabs to be joined together. It is a problem that can occur in common. In other words, for example, even in an electrical device that contains an electrical device element such as a capacitor inside, the above-described problems may occur when the electrode tabs drawn out from the electrical device are joined together. .

 [0007] The present invention has been made in view of the above-described problems, and the purpose of the present invention is to cause electrode tab members to come off when the electrode tabs drawn from the electrical device are welded together. It is an object of the present invention to provide a method for manufacturing an electric device assembly that can perform electrical connection between nug electrode tabs with high reliability.

 Means for solving the problem

[0008] In order to achieve the above object, the method of manufacturing an electrical device assembly of the present invention includes connecting the electrode tabs drawn from each electrical device, so that the plurality of electrical devices are connected in series and Z or A method of manufacturing an electrical device assembly electrically connected in parallel, in which the electrode tabs that are connected to each other are partially overlapped with each other, and the tips of the overlapped electrode tabs are! / The position is such that the displacement is directed vertically upward, and the electrode tabs are partially melted and welded together from the tip side of the electrode tabs.

[0009] According to such a manufacturing method of the present invention, each electrode tab melts in a direction from the upper side to the lower side of the overlapping portion of the electrode tabs. Compared with the conventional method in which welding is carried out with each other placed in a horizontal position, the problem of missing members is less likely to occur. [0010] Various welding methods can be used. For example, the tip of the electrode tab may be irradiated with an energy beam to melt the electrode tab.

 [0011] Further, the present invention is not limited to welding between electrode tabs, and electrode tabs that are further overlapped with a bus bar may be welded together. That is, the step of partially superimposing the electrode tabs includes superimposing a bus bar made of a conductive material in close contact with one surface of the overlapping portion of the electrode tabs, In the step of welding the tabs, the electrode tabs and the bus bar are joined by irradiating each electrode tab and the bus bar (or only one of these members) with an energy beam. May be included. In this case, the welding may be performed in a state where the overlapping portion between the electrode tabs is pressed through a bus bar.

 [0012] In addition, the step of partially overlapping the electrode tabs may include overlapping the electrode tabs with the tips of the electrode tabs aligned. The invention's effect

 [0013] As described above, according to the present invention, the electrode tabs are welded together by welding from the distal end side of the electrode tabs in a posture extending in the vertical direction. When joining, it is difficult for the electrode tabs to be removed, so that the electrode tabs can be electrically connected with high reliability.

 Brief Description of Drawings

FIG. 1 is a plan view showing an example of a configuration of a conventional assembled battery.

 FIG. 2 is a plan view showing a configuration of an assembled battery which is an embodiment of the electric device assembly manufactured by the manufacturing method of the present invention.

 FIG. 3 is a perspective view showing the battery cell of FIG. 2 in a single state.

 FIG. 4 is a perspective view showing an electrical connection portion between electrode tabs.

 FIG. 5 is a partially enlarged view showing an enlarged electrical connection between electrode tabs.

 Explanation of symbols

[0015] 20 battery cells

22 Battery element 24 Exterior film

 25a, 25b Electrode tab

 26 Overlap section

 31 Busbar

 31a Through hole

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing a configuration of an assembled battery manufactured by the manufacturing method of the present invention. FIG. 3 is a perspective view showing the battery cell of FIG. 2 in a single state. FIG. 4 is a perspective view showing the electrical connection between the electrode tabs.

 As shown in FIG. 3, the battery cell 20 alone has an exterior film 24 that forms a sealed space inside, and a predetermined electromotive force (eg, 3.6 V) is contained in the sealed space. Is a thin battery element 22 (electric device element) that outputs the same as the electrolyte. In detail, the exterior film 24 has a structure in which two films are laminated, and a sealing portion 23 in which the films are heat-sealed is formed on the entire outer periphery of the exterior film 24. The exterior film 24 has a rectangular outline shape, and a positive electrode tab 25a and a negative electrode tab 25b are drawn out from two sides on the short side. Note that the electrode tabs 25a and 25b are not particularly limited in the lead-out position. In addition to the form shown in FIG. 3, one side force is also drawn from the positive and negative electrode tabs. There may be.

 [0018] In the battery element 22, a plurality of sheet-like positive electrodes whose surfaces are coated with a positive electrode active material and sheet-like negative electrodes whose surfaces are coated with a negative electrode active material are laminated via a separator. It is a thing. The thickness of the battery element 22 is, for example, about several tens of millimeters for several millimeters of force.

[0019] The exterior film 24 is not particularly limited, but, for example, an inner surface layer having heat sealability, an intermediate layer made of a metal foil film, and an outer surface layer functioning as a protective layer are sequentially stacked. It may have a three-layer structure. The inner surface layer may be made of a thermoplastic resin excellent in electric field liquid resistance and heat sealing properties, such as polyethylene, polypropylene, polyethylene terephthalate (PET), polyamide, ionomer, and the like. For the intermediate layer, for example, an aluminum foil or a SUS foil film having flexibility and excellent strength may be used. The outer surface layer may be made of a thermoplastic resin having excellent insulating properties, such as polyamide-based resin or polyester-based resin.

 [0020] Each of the electrode tabs 25a and 25b is a sheet-like member having a thickness of 50 μm to 300 μm, for example, and has flexibility. The material of the electrode tab 25a for the positive electrode is, for example, aluminum or aluminum alloy. The material of the electrode tab 25b for the negative electrode is, for example, copper or an alloy.

 As shown in FIG. 2, in the assembled battery 50 of the present embodiment, the battery cells 20 are electrically connected so as to be connected in series. That is, a plurality of battery cells 20 are stacked in a state where the electrode tab 25a of one battery cell 20 and the electrode tab 25b of the other battery cell 20 adjacent to each other face each other. The number of battery cells 20 is not particularly limited, but may be 12, for example.

 [0022] As described above, the electromotive force of one battery cell 20 is 3.6V, and when 12 of these are assembled, the final output is about 43V. In this way, when the output is about 50V, even if the operator accidentally touches the electrode tab or the like when handling the assembled battery, the influence on the human body is relatively small. In the end, the output that can be obtained is 50V or less.

 As shown in FIG. 4, a plate-like bus bar 31 made of a conductive material (metal material) is further arranged at the electrical connection portion between the electrode tabs 25a and 25b. In the completed state of the assembled battery 50, the bus bar 31 is in close contact with the overlapping portion 26 of the electrode tabs 25a and 25b as shown in FIG. 5, so that the bus bar 31 itself is also energized.

[0024] It should be noted that the bus bar 31 can be used as various powers, for example, as a terminal for voltage extraction. When used as a terminal for voltage extraction, it is preferable that a bus bar 31 is disposed for each electrical connection between the electrode tabs as in the present embodiment. With such a configuration, for example, a predetermined electric circuit can be connected to each of the bus bars 31, and the voltage for each battery cell 20 can be detected. Alternatively, each bus bar 31 can be provided with a fuse. If a fuse is provided for each bus bar 31, in other words, for each battery cell 20, even if one battery cell 20 malfunctions, only the fuse corresponding to that battery cell 20 is blown. The entire circuit Body damage is avoided.

 [0025] As another method of using the bus bar 31, as shown by a broken line in FIG. 4, when another battery cell group is arranged adjacent to the X direction in the drawing, a longer bus bar 31 is used. It is also possible to connect the electrode tabs of one battery cell group and the electrode tabs of the other battery cell group to each other.

 [0026] The nose bar 31 has through holes 31a formed at both ends thereof. Such a through hole 31a can be used to fix the bus bar 31 to another member. Further, when a predetermined electric circuit is connected to the bus bar 31 as described above, the connection member forming one end of the electric circuit and the bus bar 31 are fastened together using the through hole 3 la. An electrical connection between the bus bar and the electrical circuit can also be made.

 [0027] Next, a method for electrically connecting the electrode tabs 25a and 25b will be described. In addition, since the other process (for example, the process of superimposing battery cells 20 etc.) in manufacturing an assembled battery can be implemented by a conventionally well-known method, the description is abbreviate | omitted.

 [0028] First, as shown in FIG. 4, the electrode tabs 25a and 25b arranged in a state of being opposed to each other are partially overlapped so that the respective tips are directed vertically upward. In this state, the overlapping portion 26 between the electrode tabs extends in the vertical direction. The electrode tabs 25a, 25b and the bus bar 31 are maintained in close contact with each other by sandwiching the electrode tabs 25a, 25b and the bus bar 31 from both sides with a pressing jig (not shown).

 [0029] In the case where the electrode tabs 25a and 25b are sandwiched with the bus bar 31 interposed therebetween, the nose bar 31 is a plate-like member, so that it is uniform with respect to the overlapping portion 26 of the electrode tab. Is applied. The uniform pressure applied to the overlapping portion 26 means that the electrode tabs 25a and 25b are stably held.

 [0030] Next, the vertical upward force is also irradiated with an energy beam toward the tip ends of the electrode tabs 25a and 25b and the end face of the bus bar 31. As a result, the electrode tabs 25a and 25b and the bus bar 31 are melted from the distal end side (the upper side in the drawing), and the members are joined together to perform welding.

[0031] As the energy beam, for example, a laser beam or an electron beam can be used. Also, as shown in FIG. 5, the tips of the electrode tabs 25a and 25b are in the same plane. If welding is performed in a state in which the electrode tabs are aligned, substantially the same amount of energy beam is irradiated to the electrode tabs 25a and 25b. If the tip positions of the electrode tabs 25a and 25b are not aligned, the amount of energy beam applied to the electrode tabs 25a and 25b may vary, and as a result, the amount of members to be melted may vary. . This can cause poor welding. Therefore, in order to improve the reliability of welding, it is preferable to align the tips of the electrode tabs as described above. From this point of view, welding may be performed by aligning the tips of the electrode tabs 25a and 25b and the end surface of the upper side of the bus bar 31.

 [0032] According to the manufacturing method of the present embodiment, each member of the electrode tabs 25a, 25b and the bus bar 31 is melted in the direction from the upper side to the lower side of the overlapping portion 26. As described with reference to FIG. 1, the problem of missing members during welding does not occur. As shown in Fig. 1, in the method of welding by irradiating the energy tabs on the electrode tabs 125a and 125b stacked in the horizontal direction, for example, if the irradiation intensity of the energy beam is too strong, a large amount of parts are melted. As a result, there was a risk that the member would come off. On the other hand, as in the present embodiment, if the material melts in the direction from the upper side to the lower side of the overlapping portion 26, even if the irradiation intensity of the energy beam is too strong, the overlapping is performed. Since the weld formed in the portion 26 only needs to be increased in the vertical downward direction, the member will not come off. In other words, this means that no problem occurs even if the energy beam is irradiated with a relatively high irradiation intensity. Therefore, according to the manufacturing method of this embodiment, the adjustment of the irradiation intensity of the energy beam is facilitated.

 In the present embodiment, the force used to weld the electrode tabs 25a, 25b and the bus bar 31. The present invention can also be applied to the case where the electrode tabs 25a, 25b are simply welded together. It is also possible to weld three or more electrode tabs.

 [0034] The main feature of the manufacturing method of the present embodiment is that the electrode tabs 25a and 25b have their tips facing directly above the lead. In other words, the overlapping portion 26 extends in the vertical direction. It is to perform welding in such a posture. Therefore, naturally, for example, after the electrode tabs are superposed in a horizontal posture, welding can be performed in the above posture.

[0035] In the method of the present invention, the member is melted from the front end side of the electrode tabs 25a, 25b, etc. As long as it can be used, it is not limited to driving the energy beam vertically downward as shown in FIG.

[0036] In addition, as a method of welding the electrode tabs, the electrode tabs 25a and 25b are not limited to those using an energy beam as long as the tip side force is also melted. For example, an ultrasonic wave is used. Other welding methods may be used. The electrical connection between the battery cells 20 is not limited to a series connection, and may be a parallel connection or a combination of parallel and series.

 [0037] It should be noted that the power described above by taking the battery cell 20 and the assembled battery 50 in which the battery cell 20 is assembled as an example. In addition to the battery, the present invention provides electrode tabs drawn from electrical device elements such as capacitors. It can utilize suitably also for joining. Specifically, the electric device element may be an electric double layer capacitor or an electrolytic capacitor.

 In FIG. 3, the member that accommodates the battery element 22 is not limited to the exterior film 24, and may be a rigid member such as a can. In addition to the stacked type in which the positive electrode and the negative electrode are stacked via the separator as described above, the battery element 22 has a positive electrode and a negative electrode in the form of a band via a separator. It may be a wound type that is thinned by laminating and winding it and then compressing it into a flat shape. The battery element 22 may be, for example, a lithium ion secondary battery, a nickel metal hydride battery, a nickel-powered battery, a lithium metal secondary Z secondary battery, or a lithium polymer battery.

Claims

The scope of the claims  [1] A method of manufacturing an electrical device assembly in which a plurality of the electrical devices are electrically connected in series and / or in parallel by connecting electrode tabs drawn from each electrical device,  The electrode tabs that are connected to each other are partially overlapped with each other, and the tips of the electrode tabs that are overlapped are vertically oriented, and the electrode tabs are attached to the electrode tabs from the tip side of the electrode tabs. A method of manufacturing an electric device assembly, the method comprising: partially melting and welding the electrode tabs.  [2] The method for manufacturing an electrical device assembly according to claim 1, wherein the step of welding the electrode tabs includes irradiating an energy beam to each tip of the electrode tabs. [3] The step of partially superimposing the electrode tabs includes superimposing a bus bar that also has a conductive material force on one surface of the overlapping portion where the electrode tabs are overlapped. Including  The electrical welding according to claim 1 or 2, wherein the step of welding the electrode tabs includes irradiating at least one of the electrode tabs and the bus bar with an energy beam to join the electrode tabs to the bus bar. A device assembly manufacturing method. [4] The electrical device assembly according to claim 3, wherein the step of welding the electrode tabs includes performing the welding in a state where the overlapping portion of the electrode tabs is pressed through the bus bar. Body manufacturing method. [5] The force 1 according to any one of claims 1 to 4, wherein the step of partially overlapping the electrode tabs includes overlapping the electrode tabs with the tips of the electrode tabs aligned. The manufacturing method of the electrical device assembly as described.