JP2009266653A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack capable of lightening weight and reducing assembly cost. <P>SOLUTION: The battery pack includes a battery pack 10 stacking a plurality of battery modules 11, fastening the modules with a fastening rod 16 passing through in the stacking direction and electrically connecting the plurality of battery modules 11; and a battery case 20 housing the battery pack 10 inside, and both end parts of the fastening rod 16 of the battery pack 10 come in direct or indirect contact with the facing inside surfaces of the battery case 20. Since the battery pack 10 is firmly supported within the battery case 20 with the fastening rod 16, the number of bolts for fastening the battery pack 10 to the battery case 20 can be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery pack.

  In recent years, an electric vehicle using an electric motor as a drive source and a so-called hybrid electric vehicle combining an electric motor as a drive source and another drive source (for example, a gasoline engine) have been put into practical use. In such a vehicle, a battery for supplying electricity as energy to the electric motor is mounted. As this battery, for example, a storage battery (secondary battery) that can be repeatedly charged and discharged is used.

  Since this type of storage battery is required to have high output, an assembled battery in which a plurality of unit cells are combined is used so that the vehicle is fixed as a battery pack containing the assembled battery in a battery case. It has become.

For example, the battery pack disclosed in Patent Document 1 includes an assembled battery obtained by further combining a plurality of battery modules in which one or more single cells are accommodated in a module case, and a battery case that accommodates the assembled battery inside and is fixed to the vehicle. And is configured.
JP 2006-236826 A

  However, the conventional battery pack has a structure in which each battery module constituting the assembled battery is bolted to the battery case so that the assembled battery is securely held in the battery case even against a strong impact. Adopted.

  In such a structure, since the battery case is bolted for each battery module, the number of bolts is large, the mass is increased, and the assembly cost is increased due to the large number of assembly steps.

  The present invention has been made based on such a conventional technique, and an object thereof is to provide a battery pack capable of reducing the manufacturing cost.

  The present invention is a battery pack including an assembled battery and a battery case that accommodates the assembled battery, and both end portions of the fastening rod of the assembled battery are in direct contact or in direct contact with opposing inner surfaces of the battery case. It is characterized by this.

  According to the present invention, the assembled battery is supported in the battery case so as to be stretched in the longitudinal direction by the fastening rod of the assembled battery. That is, since the assembled battery is firmly supported in the battery case also by the fastening rod of the assembled battery, bolts for fastening the assembled battery to the battery case can be reduced or eliminated. As a result, the battery pack can be reduced in weight, and the assembly cost can be reduced by reducing the number of assembly steps.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 to 5 show a first embodiment of the present invention. The vehicle 1 of 1st Embodiment is equipped with the vehicle-mounted structure of the assembled battery 10 as shown in FIG. That is, the on-vehicle structure of the assembled battery 10 according to the present embodiment has the assembled battery 10 as a storage battery housed in the battery case 20 to form the battery pack 9, and the battery pack 9 is fixed to the lower surface of the floor panel 3 a of the vehicle body 3. It has a structure.

Battery Case First, the battery case 20 that houses the assembled battery 10 will be described.

  As shown in FIG. 1, the battery case 20 is attached and fixed to the lower surface of the floor panel 3 a of the vehicle body 3 by bolts (not shown). The battery case 20 includes a container-like upper case member 21 and a container-like lower case member 22, and the case members 21, 22 are provided with flange portions 21 f provided at the peripheral edges of the respective openings. , 22f are screwed together to form a substantially box shape.

  On the side wall of the battery case 20 (on the side wall of the upper case member 21 in this embodiment), a wiring outlet (not shown) is formed, and the wiring 29 is drawn out of the battery case 20 from this wiring outlet. It has become.

  The wiring 29 connects the assembled battery 10 accommodated in the battery case 20 and an electric motor (on-vehicle device) (not shown) as a drive source of the vehicle 1, and for example, from the assembled battery 10 to the electric motor. Information of the assembled battery 10 is supplied to a power line that supplies driving power or, conversely, electric power (which functions as a generator in this case) to charge the assembled battery 10 or a control circuit (on-vehicle device) that controls the electric motor. For example, a signal line for transmitting (for example, the voltage of the assembled battery or the temperature of the assembled battery) is included. In addition, the wiring outlet of the battery case 20 of the battery pack 9 is connected to the wiring protective tube 30 so as to maintain hermeticity, and the wiring protective tube 30 allows the vehicle-mounted device (in this example, an electric motor) to be connected from the battery case 20. And the wiring 29 connecting the control circuit) are protected.

Next, the assembled battery will be described.

  As shown in FIGS. 3 and 4, the assembled battery 10 of the present embodiment is a combination of a plurality of flat type battery modules 11 (12 in this example), and more specifically, a plurality of stacked multi-stages. The battery modules 11 are fastened by the four fastening rods 16 penetrating in the stacking direction, and the battery modules 11 are connected by bus bars (not shown).

  As shown in FIGS. 5 to 7, each battery module 11 constituting the assembled battery 10 includes a unit cell assembly 12 in which a plurality of flat unit cells 100 are stacked and electrically connected to two case members 13 </ b> A, It is configured to be accommodated in a module case 13 formed by combining 13B.

  As shown in FIGS. 6 and 7, this unit cell assembly sandwiches a plurality of unit cells 100 and both electrode tabs of the unit cell 100 (positive electrode tab 100p, negative electrode tab 100m) from the stacking direction and is adjacent to the stacking direction. Insulating spacers 120 interposed between the electrode tabs 100p, 100m of the unit cell 100, the battery module positive terminal 14 and the battery module negative terminal 15 connected to the electrode tabs 100p, 100m of the predetermined unit cell 100, , And is configured.

  Each spacer 120 positions the electrode tabs 100p and 100m of the unit cell 100 and positions the adjacent unit cells 100 adjacent to each other in the stacking direction by positioning the spacers 120 adjacent to each other in the stacking direction (see FIGS. 6 and 7). ).

  The battery module positive terminal 14 is electrically connected to the lower unit cell 100 in FIG. 6, and includes a bus bar 141 made of a copper plate superimposed on the positive electrode tab 100 p of the unit cell 100, and the bus bar 141. And a resin cover 142 covering a terminal provided at the end. Further, the battery module negative electrode terminal 15 is electrically connected to the uppermost cell 100 in FIG. 6, and includes a bus bar 151 made of a copper plate superimposed on the negative electrode tab 100 m of the cell 100, and a bus bar 151. And a resin cover 152 covering a terminal provided at the end.

  Such a battery module 11 is provided with through holes 11h that penetrate the battery module 11 in the stacking direction at the four corners. Specifically, the through hole 11 h penetrates the spacer 120 and the module case 13.

  The battery modules 11 thus configured are stacked in a plurality of stages, and the fastening rods 16 are passed through the through holes 11h of the battery module 11 and fastened, whereby the plurality of battery modules 11 are grouped together. .

Single Cell Next, the configuration of the single cell will be described with reference to FIGS.

  The unit cell 100 of the present embodiment is a flat type lithium ion battery as described above, and a flat laminated electrode as a power generation element is arranged at the center of a laminate film as a pair of exterior films. The laminated electrode is covered with both sides of the laminated electrode, and the periphery of the laminated film is bonded by thermal welding, so that the electrolyte solution is sealed together with the laminated electrode between the laminated films. Thereby, as for the external shape of the battery, the part accommodating the laminated electrode at the center of the battery becomes a thick part, and the joint part 100a at the peripheral part of the battery becomes a thin part.

  The laminated electrode is formed by sequentially laminating a plurality of positive electrode plates and negative electrode plates with separators interposed therebetween, and each positive electrode plate is connected to a belt-like positive electrode tab 100p (electrode tab) via a positive electrode lead. Each negative electrode plate is connected to a strip-shaped negative electrode tab 100m (electrode tab) via a negative electrode lead, and the positive electrode tab 100p and the negative electrode tab 100m are drawn out from the bonded portion of the laminate film.

  The unit cell 100 may be another unit cell other than the lithium ion unit cell.

The structure for supporting the assembled battery The present embodiment is characterized by the structure for supporting the assembled battery 10 to the battery case 20, and will be described below with reference mainly to FIGS.

  The assembled battery 10 is not fastened to the battery case 20 by bolts, but is fixed to the battery case 20 by a fastening rod 16 of the assembled battery 10. That is, both end portions 16e of the fastening rod 16 of the assembled battery 10 are in pressure contact with the opposed inner side surfaces of the battery case 20, so that the fastening rod 16 of the assembled battery 10 is fixed in a stretched state in the battery case 20. The assembled battery 10 is fixed in the battery case 20. In this example, the longitudinal direction of the fastening rod 16 (the stretching direction by the fastening rod 16) extends in the vehicle width direction.

  The fastening rod 16 of the present embodiment is formed by combining a plurality of members, and specifically includes a rod body 16a, a fastening nut 16d, adjuster nuts 16e and 16e, and locking nuts 16f and 16f. It is configured. That is, the fastening rod 16 has a rod body 16a that completely penetrates the stacked battery module 11, has screw portions 16b and 16b at both ends, and has a flange portion 16c bulging at one end, and the rod body 16a. A fastening nut 16d that fastens the battery module 11 that is attached to the end portion and is stacked in multiple stages so as to be sandwiched between the flange portion 16c of the rod body 16a, and the flange portion 16c and the fastening nut 16d at both ends of the rod body. Adjuster nuts 16e and 16e that are movably attached to the outside in the longitudinal direction, and lock nuts 16f that are attached to the inside in the longitudinal direction by the adjuster nuts 16e and 16e and prevent the adjuster nuts 16e and 16e from moving in the longitudinal direction. , 16f.

  Therefore, the fastening rod 16 of this embodiment can change the length of the fastening rod 16 by moving the adjuster nut 16e in the longitudinal direction of the fastening rod 16.

Next, a method for assembling the battery pack 9 will be described.

  First, after assembling the assembled battery 10, the assembled battery 10 is accommodated in the lower case member 22 of the battery case 20. At this time, the adjuster nut 16e is moved inward in the longitudinal direction to shorten the fastening rod 16 of the assembled battery 10, whereby the assembled battery 10 can be easily accommodated in the battery case 20.

  Next, the assembled battery 10 is fixed to the lower case member 22 of the battery case 20. Specifically, after the adjuster nut 16e is moved outward in the longitudinal direction to extend the fastening rod 16 of the assembled battery 10, both ends of the fastening rod 16 are stretched against the opposing inner side surfaces of the lower case member 22. Then, the lock nut 16f is tightened in the direction of the adjuster nut 16e to fix the adjuster nut 16e. Thereby, the assembled battery 10 is fixed to the lower case member 22.

  Next, the upper case member 21 is put on the lower case member 22, the flange portions 21f, 22f of the case members 21, 22 are fixed with screws (not shown), and the assembly of the battery pack 9 to be obtained is completed.

  In such a battery pack 9, both end portions of the fastening rod 16 of the assembled battery 10 are brought into contact with the inner side surfaces of the battery case 20 so as to be stretched. It will be fixed to the case 20. Therefore, the number of bolts conventionally used for fastening and fixing the assembled battery 10 to the battery case 20 can be reduced, or can be eliminated as in this example.

Effects Next, the effects of the first embodiment will be summarized.

  (1) In this embodiment, a plurality of battery modules 11 are stacked and fastened with a fastening rod 16 penetrating in the stacking direction and electrically connected, and the assembled battery 10 is accommodated inside. The battery pack 9 is provided with a battery case 20, and both end portions of the fastening rod 16 of the assembled battery 10 are in direct or indirect contact with the opposing inner surface of the battery case 20.

  Therefore, the assembled battery 10 is fixed in the battery case 20 by fixing the fastening rod 16 of the assembled battery 10 so as to stretch on the inner surface of the battery case 20. As a result, the number of bolts conventionally used for fastening and fixing the assembled battery 10 to the battery case 20 can be reduced or eliminated as in this example, whereby the weight of the battery pack 9 can be reduced, The assembly cost can be reduced by reducing the number of assembly steps.

  (2) In the present embodiment, the extending direction of the fastening rod 16 is the vehicle width direction. Therefore, the support stability in the battery case 20 of the assembled battery 10 with respect to the input resulting from the vehicle side collision is improved.

  (3) In the present embodiment, the fastening rod 16 is movable in the longitudinal direction to the rod body 16a at least one of the rod body 16a penetrating the battery modules 11 stacked in multiple stages and both ends of the rod body 16a. And an adjuster nut 16e that can change the length of the fastening rod 16 by being attached to.

  Therefore, since the length of the fastening rod 16 can be changed, the fastening rod 16 is shortened when the assembled battery 10 is put in the battery case 20, and then the fastening rod 16 is secured when the assembled battery 10 is fixed to the battery case 20. Thus, both ends of the fastening rod 16 can be tightly and firmly adhered to the opposing inner side surfaces of the battery case 20. That is, in this embodiment, since the length of the fastening rod 16 can be changed, the stability of fixing the assembled battery 10 to the battery case 20 is maintained while maintaining the ease of assembling the assembled battery 10 to the battery case 20. Can be kept high.

  Hereinafter, other embodiments different from the first embodiment will be described. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals, and the description overlapping with that of the first embodiment is omitted.

(Second Embodiment)
Next, a fifth embodiment will be described with reference to FIGS.

  11 is a perspective view schematically showing the lower case member 22 of the battery case 20 of the second embodiment, and FIG. 12 is a relationship between the inner surface of the battery case 20 and the end of the fastening rod 16 of the assembled battery 10. FIG.

  In the second embodiment, the rough surface portion 17 is formed on both end surfaces of the fastening rod 16 by knurling or the like, and the both end surfaces 17, 17 of the fastening rod 16 abut on the inner side surface facing the battery case 20. In addition, it differs from the above-described embodiment in that the rough surface portion 27 is formed by knurling or the like.

  As a result, when both end surfaces of the fastening rod 16 are stretched to the opposite inner side surfaces of the battery case 20, the rough surface portions 17 and 17 formed on both end surfaces of the fastening rod 16 and the inner side surface of the battery case 20 are formed. The rough surface portions 27, 27 are brought into pressure contact with each other and meshed with each other, and the fastening rod 16 is less likely to be displaced in a direction perpendicular to the fastening rod 16 due to the frictional resistance between the rough surface portions 17, 27.

  Therefore, in the second embodiment, the support stability of the assembled battery 10 is improved even with respect to an impact in a direction orthogonal to the fastening rod 16 as compared with the first embodiment.

  In the present embodiment, the rough surface portion is provided on each of both end surfaces of the fastening rod 16 and the inner surface facing the battery case 20, but in the present invention, the rough surface portion is provided only on one of them. It may be provided.

  In FIG. 16, the rough surface portions 17 and 27 are deformed (exaggerated) with large irregularities for easy understanding.

(Third embodiment)
First, the second embodiment will be described with reference to FIGS. FIG. 13 is a perspective view schematically showing the relationship between the lower case member 22 of the battery case 20 of the third embodiment and the assembled battery 10, and FIG. 14 is both ends of the fastening rod 16 of the assembled battery 10 of the third embodiment. 2 is an enlarged cross-sectional view schematically showing the relationship between the battery and the inner surface of the battery case 20. FIG.

  In the present embodiment, as shown in FIGS. 13 and 14, guide grooves 25 that guide both ends of the fastening rod 16 when the assembled battery 10 is stored are provided in the lower case member 22 of the battery case 20. This is different from the first embodiment.

  After housing the assembled battery 10 in the case member 22, when both end portions of the fastening rod 16 are extended and the fastening rod 16 is brought into contact with the bottom surface of the guide groove 25 of the case member 22, the step portions on both sides of the guide groove 25. 25 b and 25 b function to prevent the fastening rod 16 from moving in a direction orthogonal to the fastening rod 16.

  The effects of the second embodiment are as follows.

  According to the second embodiment, the opposed inner surfaces of the battery case 20 are provided with step portions 25 b and 25 b that prevent the fastening rod 16 from moving in a direction orthogonal to the fastening rod 16. Therefore, since the movement of the fastening rod 16 is prevented in the direction orthogonal to the longitudinal direction of the fastening rod 16, the support stability of the assembled battery 10 is further improved.

  In addition, according to the second embodiment, the guide groove 25 that guides both ends of the fastening rod 16 when the assembled battery 10 is stored is provided in the battery case 20, and the step portions 25 b and 25 b on both sides of the guide groove 25 are provided. The step portions 25b and 25b are formed. Therefore, the assembling property of the assembled battery 10 to the battery case 20 is improved by the guide groove 25 while obtaining the above effect.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG. FIG. 16 is a perspective view schematically showing the lower case member 22 of the battery case 20 of the fourth embodiment.

  In the above-described third embodiment, the portion where the guide groove 25 is provided in the lower case member 22 is formed thinner than the surroundings, but in this embodiment, the portion where the guide groove 25 is provided is The third embodiment is different from the third embodiment in that it bulges outside the case member 22 and is formed with the same thickness as the surroundings. According to such 4th Embodiment, while the effect similar to 3rd Embodiment is acquired, the intensity | strength of the battery case 20 can be raised in the site | part which receives the fastening rod 16. FIG.

(Modification of the third and fourth embodiments)
In particular, in the structure in which the rough surface portions 17 and 27 of the second embodiment are further added to the third and fourth embodiments described above, the support stability of the assembled battery 10 is further improved.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIG.

  FIG. 16 is a perspective view schematically showing the lower case member 22 of the battery case 20 of the fifth embodiment.

  In the fifth embodiment, as shown in FIG. 16, the guide groove 25 is not formed in the lower case member 22, and the portion of the lower case member 22 that contacts the fastening rod 16 of the assembled battery 10 is This is different from the third and fourth embodiments in that it is configured as a substantially circular recess 26 that is recessed from the periphery.

  Then, both end surfaces of the fastening rod 16 of the assembled battery 10 are brought into contact with the bottom surface of the concave portion 26 formed on the inner surface facing the lower case member 22, and the assembled battery 10 is fixed to the battery case 20. It will be. At this time, the circumferential surface 26 b of the recess 26 is a stepped portion, and the movement of the fastening rod 16 in a direction orthogonal to the fastening rod 16 is restricted.

  Therefore, in the fifth embodiment, in addition to the effects as in the third and fourth embodiments, the movement restriction direction in the battery case 20 of the assembled battery 10 is set to any direction of 360 ° orthogonal to the fastening rod 16. Therefore, the support stability of the assembled battery 10 is further improved.

  As described above, as described with reference to the first to fifth embodiments, according to the present invention, the assembled battery is fixed to and held by the fastening rod of the assembled battery in the battery case. Fixed in the case. Therefore, according to the present invention, the bolts conventionally used for fastening the assembled battery to the battery case can be reduced or eliminated, the weight of the battery pack can be reduced, and the assembly cost can be reduced by reducing the number of assembly steps. Can be reduced.

  It should be noted that the present invention should not be construed as limited to the above-described embodiments.

  For example, in the above-described embodiment, the fastening rod 16 is brought into direct contact with the inner wall surface of the battery case 20, but may be brought into contact indirectly with a member such as a washer.

  In addition, it goes without saying that various modifications are possible within the scope of the technical idea of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic side view of the vehicle floor vicinity for demonstrating the vehicle-mounted structure of the battery pack of 1st Embodiment of this invention. The perspective view of the battery pack of 1st Embodiment. The exploded perspective view of a battery pack. The exploded perspective view of the assembled battery of a battery pack. The perspective view of the battery module which comprises an assembled battery. The exploded perspective view inside the module case of a battery module. The side view of FIG. The perspective view which shows the cell used for a battery module. The schematic sectional drawing of the battery pack which shows the support structure of the assembled battery with respect to a battery case. The expanded sectional view which shows the relationship between the edge part of the fastening rod of an assembled battery, and the inner surface of a battery case. The perspective view of the lower case member of the battery case of 2nd Embodiment. In the battery pack of 2nd Embodiment, the expanded sectional view which shows the relationship between the edge part of the fastening rod of an assembled battery, and the inner surface of a battery case. The disassembled perspective view of the battery pack of 3rd Embodiment. In the battery pack of 3rd Embodiment, the expanded sectional view which shows the relationship between the edge part of the fastening rod of an assembled battery, and the inner surface of a battery case. The perspective view of the lower case member of the battery case of 4th Embodiment. The perspective view of the lower case member of the battery case of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle 3 ... Vehicle body 3a ... Floor panel 9 ... Battery pack 10 ... Battery assembly 11 ... Battery module 11h ... Through-hole 12 ... Single cell assembly 13 ... Module case 14 ... Battery module positive electrode terminal 15 ... Battery module negative electrode terminal 16 ... Fastening rod 16a ... Rod body 16b ... Screw part 16c ... Flange part 16d ... Fastening nut 16e ... Adjuster nut 16f ... Locking nut 17 ... Rough surface part 20 ... Battery case 21 ... Upper case member 21f ... Flange part 22 ... Lower case member 22f ... flange portion 25 ... guide groove 25b ... step portion 26 ... recess 26b ... step portion 27 ... rough surface portion 29 ... wiring 30 ... wiring protection tube 100 ... single cell 100a ... junction part 100m ... negative electrode tab 100p ... positive electrode tab 120 ... spacer 141 ... Bus bar 142 ... Resin cover 15 ... Battery module Yuru negative terminal 151 ... bus bar 152 ... resin cover

Claims (5)

A battery assembly in which a plurality of battery modules are stacked and fastened with a fastening rod penetrating in the stacking direction, and the plurality of battery modules are electrically connected, and
A battery case for accommodating the assembled battery therein;
A battery pack comprising:
A battery pack, wherein both end portions of a fastening rod of the assembled battery are in direct or indirect contact with inner surfaces facing the battery case. The battery pack according to claim 1,
The fastening rod is
A rod body communicating the plurality of battery modules;
An adjuster nut that constitutes an end portion of the fastening rod by being attached to at least one of both end portions of the rod body so as to be movable in the longitudinal direction, and can change the length of the fastening rod; ,
A battery pack comprising: a battery pack. The battery pack according to claim 1 or 2,
A rough surface portion that prevents the fastening rod from moving in a direction orthogonal to the fastening rod is provided on at least one of both end faces of the fastening rod or the inner side faces of the battery case facing each other. Battery pack. The battery pack according to any one of claims 1 to 3,
The battery pack according to claim 1, further comprising: a step portion that prevents the fastening rod from moving in a direction orthogonal to a longitudinal direction of the fastening rod on an inner surface facing the battery case. The battery pack according to claim 4,
The battery case is provided with guide grooves for guiding both ends of the fastening rod when the assembled battery is stored in the battery case.
A battery pack, wherein the stepped portions on both sides of the guide groove are the stepped portions.

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