JP2009032411A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack with a metal connection plate capable of connecting to an output line having a flat terminal without caulking. <P>SOLUTION: A secondary battery pack houses a battery pack in which seven secondary cells are connected in series in an insulation case. A metal connection plate 6 with an output terminal function toward outside of the secondary battery pack includes a tab 6A with a thickness with its output side tip folded. An output line with a flat terminal is connected by soldering to the tab 6A of the output side tip of the metal connection plate 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an assembled battery, and more particularly to an assembled battery in which a plurality of single cells are connected by a metal connecting plate.

  In recent years, an assembled battery in which a plurality of secondary batteries are connected in series has been used as a driving source for various electric tools, electric assist bicycles, bicycles with electric motors, and electric vehicles. A metal connection plate is known as a member that electrically and mechanically connects between the terminals of adjacent unit cells. Generally, a metal connection plate is a series spot on the bottom of a battery can that also serves as a metal cap or one electrode. Welded.

  There are two types of metal connection plates that have a function of connecting between cells, and those that have an output terminal function to the outside. In the case of using the latter as a function, an output line (output cable) for output output has been conventionally used. ) Is directly caulked, and a method of caulking this and the output line has been employed (see, for example, Patent Document 1).

JP 2004-319342 A

  However, in an assembled battery in which a plurality of single cells are connected in series, when the output line is directly caulked to the metal connecting plate, it is difficult to manage the shape of the caulking portion and the strength of the caulking portion, There was a problem in quality stability. Also, during caulking of the lead-out line and subsequent assembly work, stress is easily applied to the vicinity of the caulking portion of the metal connecting plate, and deformation and the like occur, which is difficult in the work.

  An object of the present invention is to provide an assembled battery having a metal connection plate that can be connected to an output line having a flat terminal without caulking.

  In order to solve the above problems, the present invention provides a battery pack in which a plurality of single cells are connected by a metal connection plate, and has a tab having a thickness at which the output side tip of the metal connection plate is folded. Features.

  In this invention, it has the tab of the thickness by which the output side front-end | tip of the metal connection board was return | folded. For this reason, fitting connection with the output line which has a flat terminal by a tab is possible, and also contact failure can be avoided by soldering a connection part, and quality is stabilized. Further, since the output line can be attached after the assembled battery is assembled, the stress applied to the metal connecting plate can be minimized.

  According to the present invention, the output side tip of the metal connecting plate has a folded tab, so that the tab can be fitted and connected to an output line having a flat terminal. By soldering the connection part, contact failure can be avoided and the quality can be stabilized, and the output line can be attached after assembling the assembled battery, so that the stress on the metal connection plate can be minimized Can be obtained.

  Hereinafter, an embodiment in which the present invention is applied to a secondary battery pack will be described with reference to the drawings. Note that the present embodiment is an exemplification that embodies the technical idea of the present invention, and the present invention is not limited to the present embodiment.

  As shown in FIG. 2, the secondary battery pack 20 of the present embodiment is a battery in which an assembled battery 11 to which seven columnar secondary batteries 4 are connected is housed in an insulating case 12 made of resin.

For the secondary battery 4, for example, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery can be used. In this embodiment, a wound group produced by winding a positive electrode plate using lithium manganese complex oxide as a positive electrode active material and a negative electrode plate using amorphous carbon as a negative electrode active material through a microporous separator. Is fixed in a cylindrical bottomed battery can, for example, infiltrated with a nonaqueous electrolytic solution obtained by adding lithium hexafluorophosphate (LiPF ₆ ) to a mixed solvent of ethylene carbonate, dimethyl carbonate and diethyl carbonate, A secondary battery in which the opening of the can was sealed with a metal cap via a gasket was used. Further, the side peripheral surface of the secondary battery 4 is covered with a heat-shrinkable insulating film, and the metal cap and the battery can bottom serve as an output terminal of the secondary battery 4.

  The assembled battery 11 includes seven secondary batteries 4 arranged in two upper and lower stacks (four in the lower stage and three in the upper stage), the metal cap or battery can bottom of the secondary battery 4, and the metal connection plate. 5 and 6 are connected in series by series spot welding. The metal connection plate 5 is a connection plate (busbar) having a connection function between cells, and the metal connection plate 6 is a connection plate having an output terminal function to the outside. The point to be noted here is the metal connecting plate 6, as shown in FIG. 1, having a tab 6 </ b> A having a thickness that is folded back at the output side tip. The tab 6A is fixed to the flat terminal of an output line (output cable) 13 having a flat terminal by soldering (see also FIG. 4). Note that an adhesive is applied between the secondary batteries 4 in order to improve the vibration resistance of the assembled battery 11.

  The assembled battery 11 is turned upside down (upper 4 pieces, lower 3 pieces), and the arrangement length of the large number side (upper side) of the upper and lower two-stage stacking (upper four side batteries 4 are juxtaposed. Is accommodated in an insulating case 12 composed of two half cases (an insulating upper case 2 and an insulating lower case 3) having an opening of a length equal to or longer than the above.

  If this accommodation procedure is explained in full detail, first, the assembled battery 11 will be mounted in the insulating lower case 3. FIG. Also at this time, in order to improve vibration resistance, the assembled battery 11 and the insulating lower case 3 are fixed with an adhesive. Next, the insulating upper case 2 is arranged so that the tabs 5A and 6A, which are a part of the metal connection plates 5 and 6 of the assembled battery 11, protrude from slits (not shown) provided in the insulating upper case 2, and insulation is performed. Fit (join) the lower case 3. The joint part (fitting part and slit part) is closed with a sealing material or rubber packing. As is apparent from FIG. 2, the joint between the upper insulating case 2 and the lower insulating case 3 has a height corresponding to the substantially central portion of each secondary battery 4 on the larger number side of the upper and lower two layers. It is located in the direction of.

  As shown in FIG. 3, the tab 5 </ b> A is connected to each line 1 </ b> B of the voltage detection line 1. The voltage detection line 1 is a harness for detecting the voltage of each secondary battery 4 constituting the assembled battery 11, and is connected to a voltage detection device or cell controller (not shown) on the other side where the tab 5A and each line 1B are connected. It has a connection connector for connection. Each line 1B constituting the voltage detection line 1 is provided corresponding to each of the secondary batteries 4, and each line 1B is arranged separately. Electrical characteristics can be improved by soldering the connecting portions of the tab 5A and the wires 1B.

  Further, the insulating upper case 2 has a recess formed between the convex portions 2A and 2B, and a fuse 1A that is disconnected at the time of overcurrent is accommodated in the concave portion. The recess is formed at a position corresponding to a gap between the upper secondary batteries 4 accommodated in the insulating case 12. In the fuse 1A, the concave portions provided by the convex portions 2A and 2B of the insulating upper case 2 serve as a fuse holder for protecting and storing the fuse 1A. The fuse 1 </ b> A is connected to each line 1 </ b> B of the voltage detection line 1. The voltage detection line 1 is disposed on the insulating upper case 2 side, and a harness is fixed by voltage detection line protection sheets 7 and 8 with adhesive tape. Note that the upper side of the insulating upper case 2 of the secondary battery pack 20 is generally planar (see also FIG. 2).

  As shown in FIG. 4, the tab 6 </ b> A is connected to the output line 13 having a flat terminal and each line 1 </ b> B of the voltage detection line 1. Electrical characteristics are improved by soldering the connecting portions. A through hole 9 is formed in the insulating lower case 3 in preparation for the case where the internal pressure of the secondary battery pack 20 rises. A cleaving film 10 is attached to the through hole 9 on the outside of the lower insulating case 3. The cleavage membrane 10 is a semipermeable membrane that does not allow water outside the secondary battery pack 20 to pass through. In order to make the secondary battery pack 20 compact, the insulating lower case 3 has an arc-shaped portion 3A along the side surface shape of the secondary battery 4 accommodated on the bottom surface side (see also FIG. 2). In order to achieve stability when the secondary battery pack 20 is placed, a protrusion protruding toward the bottom surface is formed at a position corresponding to the gap between the secondary batteries on the lower side.

  Next, effects and the like of the secondary battery pack 20 of the present embodiment will be described.

  The secondary battery pack 20 of the present embodiment has a tab 6A having a thickness at which the output-side tip of the metal connection plate 6 is folded back, and thus has a flat terminal without being crimped by the tab 6A. Although the fitting connection with the output line 13 is possible, since this connection part is further soldered, the contact failure can be avoided, the quality is stabilized, and the output line 13 can be attached after the assembled battery 11 is assembled. The stress applied to the metal connecting plate 6 can be minimized.

  Further, in the secondary battery pack 20 of the present embodiment, the tabs 5 </ b> A and 6 </ b> A that are part of the metal connection plates 5 and 6 that electrically join the secondary battery 4 in the insulating case 12 are outside the insulating case 12. Each line 1B of the electric detection line 1 or the output line 13 is connected to the protruding part. Accordingly, the tabs 5 </ b> A and 6 </ b> A are connected to each line 1 </ b> B or the output line 13 of the voltage detection line 1 outside the insulating case 12. For this reason, according to the secondary battery pack 20, even when electrolyte solution leaks from the secondary battery 4 constituting the assembled battery 11, it is possible to avoid the risk of liquid junction with these harnesses. Further, the connection work between the tabs 5A, 6A, the electric detection lines 1B, and the output line 13 is facilitated.

  Further, in the secondary battery pack 20 of the present embodiment, seven secondary batteries 4 are arranged in a two-tiered stack, and a battery cap bottom serving as a metal cap or one of the electrodes and the metal connection plate 5. , 6 are housed in an insulating case 12 composed of an insulating lower case 3 and an insulating upper case 2 having a compact layout by series spot welding. For this reason, according to the secondary battery pack 20, even when electrolyte solution leaks from the secondary battery 4 which comprises the assembled battery 11, it can prevent the outflow to the exterior of a case.

  Furthermore, in the secondary battery pack 20 of the present embodiment, the fuse 1A is connected to each line 1B of the voltage detection line 1, and a recess for housing the fuse 1A is provided outside the insulating case 12. Therefore, according to the secondary battery pack 20, even when an overcurrent flows into each line 1B of the voltage detection line 1 due to a liquid junction due to leakage of the electrolyte from the secondary battery 4 constituting the assembled battery 11, an instantaneous The melting of the coating due to the temperature rise of each line 1B can be avoided by disconnection of the fuse 1A.

  Moreover, in the secondary battery pack 20 of this embodiment, the voltage detection line 1 is provided in each of the secondary batteries 4, and each line 1B is isolated. For this reason, according to the secondary battery pack 20, each line 1B of the voltage detection line 1 and the fuse 1A are isolated from each other by the protrusions 2A and 2B of the upper insulating case 2, and the fuse 1A is caused by an overcurrent flow. Even when the wire breaks, a short circuit between the wires 1B at the time of the wire breakage can be avoided.

  Further, in the secondary battery pack 20 of the present embodiment, the recess in which the fuse 1 </ b> A is accommodated is formed corresponding to the gap between the secondary batteries 4 on the upper side accommodated in the insulating case 12. For this reason, according to the secondary battery pack 20, the recess formed by the protrusions 2 </ b> A and 2 </ b> B of the insulating upper case 2 serving as a fuse holder effectively uses a gap that is not originally used between the secondary batteries 4. Therefore, the overall dimensions can be made compact.

  In the present embodiment, an example in which seven secondary batteries 4 are arranged in two upper and lower stages is shown. However, the present invention is not limited to the arrangement of such secondary batteries, It is generally applicable to a connection plate for connecting to an output line for external output when an assembled battery is constituted by a battery. Moreover, in this embodiment, although the insulation upper case 2 and the insulation lower case 3 were fitted together, the fitting part and the slit part illustrated the joining form which block | closes an opening part with a sealing material or rubber packing, etc., but this invention is not limited to this. For example, other joining methods such as welding can be employed.

  As described above, the present invention provides an assembled battery having a metal connection plate that can be connected to an output line having a flat terminal without crimping, and thus contributes to the manufacture and sale of secondary battery packs. Therefore, it has industrial applicability.

It is the top and side view of a metal connection board used for connection with the output line of the rechargeable battery pack of an embodiment which can apply the present invention. It is a side view of the secondary battery pack of an embodiment. It is a top view of the secondary battery pack of an embodiment. It is a bottom view of the secondary battery pack of an embodiment.

Explanation of symbols

4 Secondary battery (single cell)
6 Metal connection plate 6A Tab 11 Battery assembly 13 Output line 20 Secondary battery pack

Claims (2)

  An assembled battery in which a plurality of single cells are connected by a metal connecting plate, the assembled battery comprising a tab having a thickness obtained by folding back the front end of the metal connecting plate.   2. The assembled battery according to claim 1, wherein a flat terminal-connected output line is connected to a tab at the output-side tip of the metal connection plate.

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