JP2012059451A - Bus bar module, power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which contributes to reduction of workload when any one of a plurality of single batteries is taken out in a battery module consisting of a plurality of single batteries connected in series electrically.SOLUTION: The bus bar module comprises: a plurality of bus bar holding parts (70a) which hold a plurality of bus bars (801) that electrically connect adjoining power storage elements in a plurality of power storage elements (50) arranged in a predetermined direction; a base member (709) which positions the plurality of bus bar holding parts (70a); and a coupling part which couples at least any one of the plurality of bus bar holding parts and at least any one of the a bus bar holding part adjoining that bus bar holding part or the base member, and in which the cross-sectional area of a predetermined part is smaller than that of a part adjoining the predetermined part.

Description

  The present invention relates to a bus bar module used for electrically connecting a plurality of single cells constituting a battery module in series.

  A battery module in which a plurality of single cells are electrically connected in series is known. The plurality of single cells are connected in series by a bus bar module. In general, one bus bar module for connecting a plurality of unit cells in series is usually attached to the entire plurality of stacked unit cells. The bus bar module is fixed to each of the plurality of single cells using a plurality of bolts.

  In addition, the technique (for example, refer patent document 1) regarding the accommodation structure to the battery storage space of a cell, the technique (for example, refer patent document 2) using a flexible coupling tool for the connection between unit cells, In addition, a technique for reducing the size and weight while stabilizing the shape of an assembly of many power storage elements (see, for example, Patent Document 3) is known.

Japanese Patent Laying-Open No. 2005-085595

JP 2007-042630 A

JP 2006-324060 A

  In the conventional technology described above, when any one of the cells constituting the battery module is to be removed for some reason, all the bolts fixed to each of the plurality of cells must be removed, resulting in a large work load. It was.

  Accordingly, an object of the present invention is a technology that can contribute to a reduction in work load when removing any of a plurality of unit cells in a battery module in which a plurality of unit cells are electrically connected in series. Is to provide.

  The bus bar module according to the present invention includes a plurality of bus bar holding portions that hold a plurality of bus bars for electrically connecting adjacent power storage elements in a plurality of power storage elements arranged in a predetermined direction, and the plurality of bus bars. A base member for positioning the holding portion, at least one of the plurality of bus bar holding portions, and a bus bar holding portion adjacent to the bus bar holding portion and at least one of the base members are connected, and a predetermined portion is disconnected. A connecting portion having a smaller area than other portions adjacent to the predetermined portion.

  Here, the predetermined portion is provided at a position different from a position where the bus bar is held in a direction orthogonal to a direction in which the plurality of bus bar holding portions are arranged.

  Here, the connecting part forms a standing wall part standing so as to protrude in a direction orthogonal to a direction in which the plurality of bus bar holding parts are arranged between adjacent bus bar holding parts, and the standing wall The position of the bus bar is regulated by the side wall of the part.

  Here, the predetermined portion is a top portion of the standing wall portion.

  Here, the predetermined portion has a small cross-sectional area due to the notch.

  Here, the standing wall portion is erected by bending the connecting portion, and the notch is formed on the upper surface and the lower surface of the top portion of the standing wall portion.

  The power storage device according to the present invention includes a bus bar module configured as described above, a plurality of bus bars held by the plurality of bus bar holding portions in the bus bar module, and a plurality of power storage elements to which the bus bars are connected. Prepare.

  ADVANTAGE OF THE INVENTION According to this invention, in the battery module formed by connecting several unit cells electrically in series, it can contribute to reduction of the work burden in the case of removing any one of several unit cells partially. Provide technology.

It is an exploded view which shows the structure of a battery pack. 4 is a plan view showing details of a bus bar module in Embodiment 1. FIG. It is A-A 'sectional drawing of the bus-bar module 7a in FIG. It is the elements on larger scale of the A-A 'cross section of the bus-bar module 7a in FIG. It is a figure which shows a mode that the volt | bolt which has fixed the bus-bar 801 to the cell 50 is removed, and the said bus-bar holding | maintenance part 70a is pulled up. It is sectional drawing which shows the shape of the weak part 701v of the bus-bar module 7b in Example 2. FIG. It is sectional drawing which shows the shape of the weak part 701u of the bus-bar module 7c in Example 3. FIG. It is a top view which shows schematic structure of the bus-bar module 7d in Example 4. FIG. It is a top view which shows the bus-bar module 7d of the state which removed only some bus-bar cases 620. FIG. 10 is a partial perspective view showing a schematic configuration in the vicinity of the removed bus bar case 620 of the bus bar module 7d in the state of FIG. 9;

  First, Example 1 of the present invention will be described.

  A configuration of a battery pack (power storage device) that is Embodiment 1 of the present invention will be described with reference to FIG. Here, FIG. 1 is an exploded view showing a configuration of the battery pack. The battery pack of this embodiment can be mounted on a vehicle, and examples of the vehicle include a hybrid vehicle and an electric vehicle. A hybrid vehicle is a vehicle that includes an internal combustion engine and a fuel cell in addition to a battery pack as a power source for generating running energy (kinetic energy) of the vehicle. An electric vehicle is a vehicle that uses only the output of a battery pack to drive the vehicle.

  The battery pack 900 includes a battery module (storage module) 10 formed by electrically connecting a plurality of single cells (storage elements) 50 in series. Here, a plurality (for example, 28) of unit cells 50 are arranged (stacked) in the x-axis direction shown in FIG. A spacer (not shown) is disposed between two adjacent unit cells 50 of each of the plurality of unit cells. A spacer forms the space for moving the air etc. which are used for the temperature control of the cell 50 between the two cell 50 arrange | positioned adjacently.

  In addition, as the single battery 50 here, a secondary battery such as a lithium ion battery or a nickel metal hydride battery can be used. An electric double layer capacitor can be used instead of the secondary battery. On the other hand, the number of single cells 50 constituting the battery module 10 can be appropriately set based on the output performance that the battery module 10 has.

  In addition, a pair of end plates 53 are arranged at both ends of the battery module 10 in the arrangement direction of the unit cells 50, and the pair of end plates 53 are constraining rods 54 a and 54 b extending in the arrangement direction of the unit cells 50. Are connected two by two. Thereby, the force (restraint force) in the direction in which the adjacent unit cells 50 are brought close to each other acts on the plurality of unit cells 50 constituting the battery module 10. This restraining force can suppress the thermal expansion of the unit cell 50.

  A plus terminal 50 a and a minus terminal 50 b are provided on the upper surface of each unit cell 50. The plus terminal 50a of each unit cell 50 is electrically connected to the minus terminal 50b of another unit cell 50 disposed adjacent to the unit cell 50.

  The bus bar module 7a is used to electrically connect a plurality of single cells 50 constituting the battery module 10 in series. In FIG. 1, for convenience of explanation, the bus bar module 7a is simply displayed. The bus bar module 7 a is arranged so as to cover the upper surface of the unit cell 50.

  As shown in FIG. 2, the bus bar module 7 a includes a plurality of bus bars 801 for electrically connecting the plus terminals 50 a and the minus terminals 50 b of the adjacent unit cells 50, and a base 709 for holding these bus bars 801. (Corresponding to a base member and a bus bar holding portion). Each bus bar 801 is formed of a conductive material (for example, metal), and the base 709 is formed of a non-conductive material (for example, resin).

  Among the plurality of unit cells 50 constituting the battery module 10, the plus terminal 50 a of the unit cell 50 positioned at one end in the arrangement direction becomes the total plus terminal of the battery module 10. The total plus terminal 50a is connected to a not-shown total plus cable (high voltage cable) used for charging / discharging the battery module 10. Specifically, the connection terminal provided at one end of the total plus cable contacts the bus bar 801 connected to the total plus terminal 50a in the bus bar module 7a.

  In addition, among the plurality of unit cells 50 constituting the battery module 10, the minus terminal 50 b of the unit cell 50 located at the other end in the arrangement direction is a total minus terminal of the battery module 10. A total minus cable (not shown) used for charging / discharging the battery module 10 is connected to the total minus terminal 50b.

  In this embodiment, the output of the battery module 10 is boosted by a DC / DC converter, converted into AC power by an inverter, and then supplied to a motor / generator. As a result, the motor / generator is driven and the traveling energy (kinetic energy) of the vehicle is generated. On the other hand, when the vehicle is braked, the electric power generated by the motor / generator is converted into direct-current electric power by the inverter and is stepped down by the DC / DC converter, and then supplied to the battery module 10. Thereby, the battery module 10 is charged.

  Next, the structure of the bus bar module 7a of the present embodiment will be described with reference to FIGS. Here, FIG. 2 is a plan view of the bus bar module 7a as viewed from above (Z-axis direction). FIG. 3 is a cross-sectional view taken along the line A-A ′ of the bus bar module 7 a in FIG. 2. FIG. 4 is a partially enlarged view of the A-A ′ cross section of the bus bar module 7 a in FIG. 2.

  The base 709 of the bus bar module 7a is provided with a plurality of bus bar holding portions 70a for individually holding the plurality of bus bars 801. The plurality of bus bar holding portions 70a are in the X-axis direction (in this case, 28) in the X-axis direction (28) in the stack direction (X-axis direction) of the single cells 50 in the battery module 10 in which the bus bar module 7a is installed Are arranged in a predetermined direction). Here, the relative positional relationship is prescribed | regulated by the base member which comprises some bases 709 for the some bus-bar holding | maintenance part 70a. As long as the shape of the base member can define the relative positional relationship of the plurality of bus bar holding portions 70a as a result, any shape can be adopted.

  Each of the bus bar holding portions 70a is provided with a bottom surface portion 701e on which the bus bar 801 is placed, and is erected so as to extend upward (in the Z-axis direction) from the bottom surface portion 701e. ) And a side wall portion 702 that is erected upward from the bottom surface portion 701e and extends in parallel with the stack direction (X direction) of the plurality of single cells 50, It has. Two side walls 702 are provided in parallel from both ends of the bottom surface 701e (see FIG. 2).

  The standing wall portion 701 includes a first standing wall portion 701c and a second standing wall portion 701d, and the first standing wall portion 701c and the second standing wall portion 701d located at both ends of the bottom surface portion 701e. Bus bar 801 is held in the space between the two.

  The bus bar holding portion 70a is surrounded by the bottom surface portion 701e, the first standing wall portion 701c, the second standing wall portion 701d, and the side wall portion 702 so as to surround four side end surfaces parallel to the z-axis direction of the bus bar 801. To support. Thereby, the big position shift etc. of the bus bar 801 with respect to the base 709 are controlled. Note that the first standing wall portion 701c, the second standing wall portion 701d, and the side wall portion 702 do not need to be in close contact with the four side end surfaces parallel to the z-axis direction of the bus bar 801, and the bus bar 801 is a single cell by bolts. When the position of the hole of the bus bar 801 is regulated so that the position of the hole of the bus bar 801 can be fastened to the electrode, there may be some backlash.

  In addition, the first standing wall portion 701c and the second standing wall portion 701d in the standing wall portion 701 are connected to each other by a fragile portion 701b formed in a shape that is easily damaged (see FIG. 4). reference). The fragile portion 701b connects at least one of the plurality of bus bar holding portions 70a and the bus bar holding portion 70a adjacent to the bus bar holding portion 70a.

  Adjacent bus bar holding portions 70a are standing wall portions 701 standing between the adjacent bus bar holding portions 70a so as to protrude in the Z-axis direction (a direction perpendicular to the direction in which the plurality of bus bar holding portions are arranged). And the position of the bus bar 801 is regulated by the side wall of the standing wall portion 701.

  The standing wall portion 701 is erected by bending a portion (connecting portion) that connects the adjacent bus bar holding portions 70a, and the notch is formed on the upper surface and the lower surface of the top portion (predetermined portion) of the standing wall portion 701. ing. That is, the cross-sectional area of the top portion of the standing wall portion 701 is set smaller than other portions adjacent to the top portion. Thus, by making the cross-sectional area of the predetermined portion smaller than that of the other portions, stress concentration is likely to occur in the predetermined portion when an external force is applied to the bus bar holding portion 70a.

Next, details of the configuration of the fragile portion 701b will be described.
FIG. 5 shows that the bolts fixing the bus bar 801 held by the bus bar holding unit 70a to the unit cell 50 are removed only for the bus bar holding unit 70a corresponding to a part of the unit cells 50 to be removed. It is a figure which shows a mode that the bus-bar holding | maintenance part 70a is pulled up upwards. In FIG. 5, in order to simplify the drawing, bolts are not shown for the bus bar holding portion that is not removed.

  The fragile portion 701b has a shape that can be easily broken by applying an external force such as pulling the bottom surface portion 701e upward or pushing it downward. Specifically, the fragile portion 701b has a shape in which a cut is made from above and below at a portion connecting the top portions of the first standing wall portion 701c and the second standing wall portion 701d. These notches have a V-groove shape extending in a direction orthogonal to the arrangement direction (X-axis direction) of the unit cells 50. Such a cut causes an increase in breakability due to an increase in the notch coefficient and an increase in stress due to a decrease in cross-sectional area in the fragile portion 701b, and the fragile portion 701b can be easily broken only by applying a weak external force. Can do.

  In this manner, the desired unit cell can be removed without removing the entire bus bar module 7a by removing only the bolt corresponding to the bus bar holding portion 70a that is bolted to the unit cell 50 to be removed from the battery module 10. Removal of 50 units alone can be realized.

  Further, the predetermined portion that is easily broken or deformed is provided at a position different from the position where the bus bar 801 is held in a direction (Z-axis direction) orthogonal to the direction in which the plurality of bus bar holding portions 70a are arranged. Thereby, for example, when an external force is applied to grab the vicinity of the bottom surface portion 701e and pull it upward, a large stress concentration can be caused in a predetermined portion by the lever principle.

  Next, a second embodiment of the present invention will be described.

  In the second embodiment of the present invention, the shape of the weakened portion formed on the standing wall portion 701 is different from that of the first embodiment. Hereinafter, in the present embodiment, portions having the same functions as those in the configuration shown in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 6 is a cross-sectional view illustrating the shape of the fragile portion 701v of the bus bar module 7b according to the second embodiment.

  The fragile portion 701v has a shape that is easily broken by applying an external force such as pushing down the bottom surface portion 701e. Specifically, the fragile portion 701v has a shape in which a cut is made from above at a portion connecting the tops of the first standing wall portion 701c and the second standing wall portion 701d. These notches have a V-groove shape extending in a direction orthogonal to the arrangement direction (X-axis direction) of the unit cells 50. Such a cut causes an increase in notch coefficient due to an increase in the notch coefficient and an increase in stress due to a decrease in cross-sectional area in the fragile portion 701v, and the fragile portion 701v can be easily broken only by applying a weak external force. Can do.

  Next, Embodiment 3 of the present invention will be described.

  In the third embodiment of the present invention, the shape of the weakened portion formed on the standing wall portion 701 is different from that of the first embodiment. Hereinafter, in the present embodiment, portions having the same functions as those in the configurations shown in the first embodiment and the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 7 is a cross-sectional view illustrating the shape of the weakened portion 701u of the bus bar module 7c according to the third embodiment.

  The fragile portion 701u has a shape that is easily broken by applying an external force such as pulling up the bottom surface portion 701e. Specifically, the fragile portion 701u has a shape in which a cut is made from above at a portion connecting the top portions of the first standing wall portion 701c and the second standing wall portion 701d. These notches have a V-groove shape extending in a direction orthogonal to the arrangement direction (X-axis direction) of the unit cells 50. Such a cut causes an increase in notch coefficient due to an increase in the notch coefficient and an increase in stress due to a decrease in the cross-sectional area in the fragile portion 701u, so that the fragile portion 701u can be easily broken only by applying a weak external force. Can do.

  In the first to third embodiments described above, the configuration in which the bus bar holding portion 70a can be detached from the base 709 is illustrated. However, the configuration is not necessarily limited thereto, and as a result, the entire bus bar module 7a is removed from the battery module 10. It is only necessary to be able to remove only the unit cell to be exchanged without removing it. Therefore, only one of the two standing wall portions constituting the bus bar holding portion 70a can be easily broken, and the other top portion can be bent (can be developed with the other as a fulcrum). It is good also as a structure.

  Further, in the above-described first to third embodiments, the configuration in which the standing wall portion is provided with the portion that can be easily broken or deformed is not necessarily limited to this. For example, the bottom portion 701e and Needless to say, it is possible to similarly provide a portion that can be easily broken or deformed with respect to a portion that connects the side wall portion 702 (connecting portion) and a portion that connects the side wall portion 702 and the base 709 (connecting portion). .

  Embodiment 4 of the present invention will be described below.

  The fourth embodiment of the present invention is a modification of the above first to third embodiments. Hereinafter, in the present embodiment, parts having the same functions as the configurations shown in Embodiments 1 to 3 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 8 is a plan view illustrating a schematic configuration of the bus bar module 7d according to the fourth embodiment. In FIG. 8, for the sake of convenience of explanation, the unit cell 50 is simplified to a configuration in which six unit cells 50 are arranged in the X-axis direction. It is assumed that 28 bus bar cases 620 arranged in the X-axis direction corresponding to the battery 50 are provided.

  As shown in FIG. 8, the bus bar module 7 d according to the fourth embodiment includes an outer frame 610 and a plurality of bus bar cases 620 arranged and fitted inside the outer frame 610. Each bus bar case 620 is fitted in a state of being arranged adjacent to the inside of the outer frame 610, and the upper part of each bus bar case 620 is engaged with an engaging portion 611 provided on the outer frame 610. Accordingly, it is possible to prevent the bus bar cases 620 from dropping from the outer frame 610 when the bus bar module 7d is attached to the battery module including the plurality of single cells 50. The engaging portion can be provided on each bus bar case 620 side, or can be provided on both the bus bar case 620 and the outer frame 610.

  Each bus bar case 620 has a rectangular outer shape when viewed in the X-axis direction, and a pair of L-shaped standing wall portions 620n are erected upward from the rectangular bottom portion 620e that is long in the Y-axis direction. Has been. The bus bar 801 is placed on the upper surface of the bottom portion 620e, and the position in the XY plane direction is regulated by the side wall of the standing wall portion 620n.

  Further, each bus bar case 620 has an opening 620h for allowing the bus bar 801 to pass therethrough in order to allow electrical connection by the bus bar 801 between the cells corresponding to the adjacent bus bar cases.

  Thus, the bus bar case 620 corresponding to each unit cell is configured independently, and each bus bar case 620 is configured to be individually removable from the outer frame 610. Even in the case of partially replacing any of the above, it is possible to replace the battery by simply removing the bolt K corresponding to the bus bar case 620 corresponding to the unit cell to be replaced. Can contribute to the reduction of burdensome work. FIG. 9 is a plan view showing the bus bar module 7d with only some of the bus bar cases 620 removed. FIG. 10 is a partial perspective view showing a schematic configuration in the vicinity of the removed bus bar case 620 of the bus bar module 7d in the state shown in FIG.

  In the present embodiment, the case where the bus bar module is attached to the so-called box-type cell 50 is illustrated, but the present invention is not necessarily limited thereto. For example, a plurality of cylindrical unit cells may be packaged in a state of being electrically connected, and the packaged unit cell may be arranged as the unit cell 50 in the above-described Examples 1 to 4.

  Further, in this embodiment, the configuration in which the positional deviation of the bus bar 810 in the XY plane direction is regulated by the L-shaped standing wall portion 620n is not necessarily limited thereto. That is, the shape and the number of bus bars 801 held by the bus bar case 602 are determined according to the number and position of the electrodes of the unit cell to which the bus bar case 620 is fixed. Therefore, the shape of the standing wall 620n is not limited as long as the bus bar 801 to be held can be held at an appropriate position.

900: Battery pack (power storage device) 10: Battery module (power storage module)
50: Single cell (electric storage element) 50a: Positive terminal 50b: Negative terminal 7a, 7b, 7c, 7d: Bus bar module 801: Bus bar K: Bolt 709: Base 70a: Bus bar holding portion 701e: Bottom portion 701: Standing wall portion 702 : Side wall part 701b, 701v, 701u: Fragile part 610: Outer frame 620: Bus bar case 611: Engagement part 620e: Bottom part 620n: Standing wall part

Claims (7)

A plurality of bus bar holding portions for holding a plurality of bus bars for electrically connecting adjacent power storage elements in a plurality of power storage elements arranged in a predetermined direction;
A base member for positioning the plurality of bus bar holding portions;
At least one of the plurality of bus bar holding portions is connected to at least one of the bus bar holding portion and the base member adjacent to the bus bar holding portion, and the cross-sectional area of the predetermined portion is other than the predetermined portion. A smaller connecting part than the part of
A bus bar module comprising:   The bus bar module according to claim 1, wherein the predetermined portion is provided at a position different from a position where the bus bar is held in a direction orthogonal to a direction in which the plurality of bus bar holding portions are arranged.   The connecting portion forms a standing wall portion standing so as to protrude in a direction orthogonal to a direction in which the plurality of bus bar holding portions are arranged between adjacent bus bar holding portions, and a side wall of the standing wall portion The bus bar module according to claim 1 or 2, wherein the position of the bus bar is regulated by the above.   The bus bar module according to claim 3, wherein the predetermined portion is a top portion of the standing wall portion.   The bus bar module according to claim 1, wherein the predetermined portion has a cross-sectional area that is reduced by a notch. The standing wall portion is erected by bending the connecting portion,
The bus bar module according to claim 3, wherein the notch is formed on an upper surface and a lower surface of a top portion of the standing wall portion. The bus bar module according to any one of claims 1 to 6,
A plurality of bus bars held by the plurality of bus bar holding portions in the bus bar module;
A plurality of power storage elements to which the bus bar is connected;
A power storage device comprising:

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