JP2019067668A - Battery pack - Google Patents

Abstract

To provide a battery pack that enables stable bonding with a cell by a holder having a relatively simple structure.SOLUTION: A battery pack 1 comprises: a plurality of cells 30 each having a cap surface 304 provided with a pair of electrode terminals 301 and 302; and a holder 10 that holds the plurality of cells 30 on the cap surfaces 304. The holder 10 has: hole parts 12 into which the pair of electrode terminals 301 and 302 can be inserted; ribs 13 located between the respective cells 30; groove parts 16 located at both sides of each rib 13; and recessed parts 17 located between the pair of hole parts 12. The cells 30 are bonded with the holder 10 by an adhesive agent 14 applied to the groove parts 16 and the recessed parts 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery pack.

  Conventionally, when a cell is bonded to a holder with an adhesive, an adhesive reservoir may be formed in the holder (see, for example, Patent Document 1).

JP, 2010-108733, A

  If the adhesive reservoir is formed by providing the holder with a protrusion, the structure of the holder may be complicated.

  An object of the present invention made in view of such a point of view is to provide an assembled battery which can be stably joined to a cell by a holder having a relatively simple structure.

In order to solve the above problems, the battery pack according to the first aspect is:
A plurality of cells having a cap surface on which a pair of electrode terminals are provided;
And a holder for holding the plurality of cells on the cap surface,
The holder includes a hole through which the pair of electrode terminals can be inserted, a rib located between the cells, a groove located on both sides of the rib, and a recess located between the pair of holes Have
The cell is bonded to the holder with an adhesive applied to the groove and the recess.

  According to the battery assembly of the first aspect, the cells can be stably joined by the holder having a relatively simple structure.

It is a perspective view which shows the structural example of the assembled battery which concerns on one Embodiment. It is a perspective view which shows the structural example of the cell accommodated in a battery module. It is a perspective view which shows the structural example of a cell. It is AA sectional drawing of FIG. It is a (A) perspective view (B) top view which shows the structural example of a holder. It is an (A) perspective view (B) top view showing an example of composition of a case. It is a flowchart which shows an example of the assembly procedure of an assembled battery. It is a perspective view which shows an example of the state in the middle of an assembly of an assembled battery. It is a top view which shows an example of a structure of a cell joint surface. It is an (A) section perspective view (B) sectional view showing an example of a crevice of a cell junction side. It is an (A) section perspective view (B) sectional view showing an example of a crevice of a cell junction side. It is an (A) section perspective view (B) sectional view showing an example of a crevice of a cell junction side. It is an (A) cross-sectional perspective view (B) BB sectional drawing which shows an example of the recessed part of a cell joint surface. It is a top view which shows the example of the crimp shape which the recessed part of a cell joint surface has.

  Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. The drawings are schematic. The dimensions or proportions in the drawings do not necessarily match the actual ones. The depiction of each component in each figure may be partially simplified.

  As shown in FIG. 1, an assembled battery 1 according to an embodiment includes a holder 10 and a case 20. The battery assembly 1 accommodates the cells 31, 32, 33, 34 and 35 in a portion surrounded by the holder 10 and the case 20. The cells 31, 32, 33, 34 and 35 are collectively referred to as the cell 30. The configuration in which the cell 30 is surrounded by the holder 10 and the case 20 is also referred to as a battery module. That is, the cell 30 is accommodated inside the battery module. The holder 10 and the case 20 may be made of, for example, a resin such as PP (Polypropylene) or PBT (Poly-Butylene Terephthalate). The cell 30 may be, for example, a secondary battery such as a lithium ion battery or a nickel hydrogen battery.

  As shown in FIG. 2, the cells 31, 32, 33, 34 and 35 respectively have positive electrode terminals 311, 321, 331, 341 and 351 and negative electrode terminals 311, 321, 331, 341 and 351. The positive electrode terminals 311, 321, 331, 341 and 351 are collectively referred to as the positive electrode terminal 301. The negative electrode terminals 311, 321, 331, 341 and 351 are collectively referred to as the negative electrode terminal 302. The positive electrode terminal 301 and the negative electrode terminal 302 are collectively referred to as an electrode terminal. The cell 30 can be said to have two electrode terminals. The cell 30 can be said to have a pair of electrode terminals.

  The battery assembly 1 further includes an insulating sheet 50 between the cells 30. The insulating sheet 50 insulates between the cells 30. The insulating sheet 50 may be made of an insulating resin or film.

  As shown in FIG. 3, the cells 30 have a substantially rectangular parallelepiped shape. The cell 30 has a cap surface 304 facing in the positive direction of the Z-axis and a back surface 305 facing in the negative direction of the Z-axis. The cell 30 has two flat surfaces 306 facing in the positive and negative directions of the X axis. The cell 30 has two side surfaces 307 that face in the positive and negative directions of the Y axis. The cells 30 are arranged such that the flat surfaces 306 face each other, and are housed inside the battery module.

  The cell 30 has a positive electrode terminal 301, a negative electrode terminal 302, and a safety valve 303 on the cap surface 304. The positive electrode terminal 301, the negative electrode terminal 302, and the safety valve 303 are arranged in the longitudinal direction of the cap surface 304. The safety valve 303 can be opened to discharge the gas to the outside when the pressure inside the cell 30 becomes equal to or higher than a predetermined pressure by the gas generated inside the cell 30. The pressure inside the cell 30 can become equal to or higher than a predetermined pressure, for example, when the cell 30 is aged or thermally runaway. The predetermined pressure may be appropriately determined in accordance with the specification of the cell 30.

  As shown in FIG. 1, the battery assembly 1 includes a total minus terminal bus bar 40, intercell bus bars 41, 42, 43 and 44, and a total plus terminal bus bar 45. The inter-cell bus bar 41 electrically connects the positive electrode terminal 311 and the negative electrode terminal 322. The inter-cell bus bar 42 electrically connects the positive electrode terminal 321 and the negative electrode terminal 332. The inter-cell bus bar 43 electrically connects the positive electrode terminal 331 and the negative electrode terminal 342. The inter-cell bus bar 44 electrically connects the positive electrode terminal 341 and the negative electrode terminal 352. The total negative terminal bus bar 40 is electrically connected to the negative terminal 312 at one end. The total plus terminal bus bar 45 is electrically connected to the positive electrode terminal 351 at one end.

  Five cells 30 are connected in series between the total minus terminal bus bar 40 and the total plus terminal bus bar 45. The potential difference between the total minus terminal bus bar 40 and the total plus terminal bus bar 45 corresponds to the sum of the voltages of the respective cells 30. The sum of the voltages of the cells 30 is also referred to as a total voltage. The battery assembly 1 can output current to a load device such as a starter or an external device such as a battery control device through the total minus terminal bus bar 40 and the total plus terminal bus bar 45. The battery assembly 1 can be supplied with current from a power generation device such as an alternator or another battery through the total minus terminal bus bar 40 and the total plus terminal bus bar 45.

  The total minus terminal bus bar 40, the total plus terminal bus bar 45, and the inter-cell bus bars 41, 42, 43 and 44 are collectively referred to as bus bars. The bus bar may be made of, for example, a conductive metal such as copper or aluminum. The bus bar may be welded to the electrode terminal. The bus bar may be electrically connected to the electrode terminal by other methods such as crimping.

  As shown in FIG. 4, FIG. 5 (A) and FIG. 5 (B), the holder 10 has a cell holding surface 11. The holder 10 holds the cell 30 by being joined to the cap surface 304 of the cell 30 at the cell holding surface 11. In other words, the cap surface 304 is held by the cell holding surface 11. The holder 10 is provided with a hole 12, a first rib 13 and a safety valve hole 15 in the cell holding surface 11. The first rib 13 is also simply referred to as a rib.

  The hole 12 is a through hole, and the positive electrode terminal 301 and the negative electrode terminal 302 of the cell 30 can be inserted toward the outside of the battery module. In other words, the positive electrode terminal 301 and the negative electrode terminal 302 can be inserted through the hole 12 toward the outside of the battery module. The hole 12 is provided at a position corresponding to at least the electrode terminal of the cell 30. If the cell 30 has two electrode terminals, the holder 10 has at least two holes 12. The holder 10 may have three or more holes 12. The holder 10 may have a pair of holes 12 at positions corresponding to the pair of electrode terminals of the cell 30. In FIG. 4, the hole 12 is provided at a position corresponding to the positive electrode terminal 331 and the negative electrode terminal 342, and inserts the positive electrode terminal 331 and the negative electrode terminal 342 into the outside of the battery module.

  The first rib 13 is located between the cells 30 held by the cell holding surface 11. That is, the cells 30 are partitioned by the first ribs 13.

  The safety valve hole 15 is a through hole, and can connect the safety valve 303 of the cell 30 to the outside of the battery module. The safety valve hole 15 is provided at a position corresponding to the safety valve 303 of the cell 30.

  In FIG. 4, the inter-cell bus bar 43 has a welding opening 46. The inter-cell bus bar 43 is joined to the positive electrode terminal 331 and the negative electrode terminal 342 at the periphery of the welding opening 46 by welding such as bead welding, for example. The inter-cell bus bar 43 electrically connects the positive electrode terminal 331 and the negative electrode terminal 342. The welding openings 46 are provided not only in the inter-cell bus bar 43 but also in the inter-cell bus bars 41, 42 and 44.

  In FIG. 5B, the cells 31, 32, 33, 34 and 35 are shown by broken lines. The cell 30 may be bonded to the cell holding surface 11 by an adhesive 14. The adhesive 14 may be made of various materials capable of adhering the cell 30 and the holder 10 to each other. The adhesive 14 may be, for example, an acrylic adhesive or an epoxy adhesive. The adhesive 14 may be applied at a location corresponding to the end of the cap surface 304 on the positive and negative sides of the X-axis. That is, the cell 30 may be bonded to the cell holding surface 11 at the end on the positive and negative sides of the cap surface 304 on the X axis. The adhesive 14 may be applied to both sides of the first rib 13. The adhesive 14 may be applied to the end of the cell holding surface 11 on the positive and negative sides of the X axis. The adhesive 14 may be applied between the hole 12 and the safety valve hole 15.

  As shown in FIG. 4, FIG. 6 (A) and FIG. 6 (B), the case 20 has a bottom surface 21. The case 20 includes a second rib 22 on the bottom surface 21. The second rib 22 is provided between the cells 30 housed in the case 20. That is, the cells 30 are partitioned by the second ribs 22.

  In FIG. 6B, the cells 31, 32, 33, 34 and 35 are shown by broken lines. The cells 30 may be bonded to the bottom surface 21 by an adhesive 14. The adhesive 14 may be applied near the center of the back surface 305. That is, the cells 30 may be bonded to the bottom surface 21 at the back surface 305.

  The battery assembly 1 can be assembled according to the procedure shown in the flowchart of FIG. The state in the middle of assembling the battery assembly 1 is shown in FIG. 8 (A), FIG. 8 (B), FIG. 8 (C) and FIG. 8 (D).

  The adhesive 14 is applied to the holder 10 (step S1). The adhesive 14 may be applied to the cell holding surface 11 at the position shown in FIG. 5 (B).

  The cell 30 is bonded to the holder 10 (step S2). The state of step S2 is shown in FIG. 8 (A).

  The insulating sheet 50 is inserted between the cells 30 (step S3). The state of step S3 is shown in FIG. 8 (B).

  The adhesive 14 is applied to the case 20 (step S4). The adhesive 14 may be applied to the bottom 21 at the position shown in FIG. 6 (B). Step S4 may not be performed.

  The case 20 is put on the cell 30 (step S5). The state of step S5 is shown in FIG. 8 (C).

  The bus bar is welded to the electrode terminal of the cell 30 (step S6). The state of step S6 is shown in FIG. 8 (D). The axis in FIG. 8 (D) is opposite to the axis in FIGS. 8 (A), 8 (B) and 8 (C).

  As shown in FIG. 9, the holder 10 has a cell holding surface 11 sandwiched by first ribs 13 located along the Y-axis direction. The holder 10 has a hole 12, a safety valve hole 15 and a recess 17 in the cell holding surface 11. The recess 17 may be located between the holes 12 aligned in the Y-axis direction. The recess 17 may be located between the pair of holes 12 corresponding to the pair of electrode terminals of the cell 30. In other words, the recess 17 may be positioned in line with the hole 12 in the direction along the first rib 13. The recess 17 may be located between the hole 12 and the safety valve hole 15 aligned in the Y-axis direction. The recess 17 may be adjacent to the hole 12.

  As shown in FIGS. 10A and 10B, the holder 10 has grooves 16 on the positive and negative sides of the X axis as viewed from the first rib 13. That is, the grooves 16 are located on both sides of the first rib 13. The recess 17 has a bottom surface 17 a and a side surface 17 b. When viewed from the cell holding surface 11, the depth of the groove 16 and the depth of the recess 17 may be the same or may be different from each other. The groove portion 16 and the recess portion 17 may be collectively formed when the holder 10 is formed, or may be formed by various processes such as embossing.

  If the cells 30 are bonded to the holder 10 by means of an adhesive 14, the adhesive 14 may be applied to the cell holding surface 11, for example by means of an applicator. If the adhesive 14 is applied aiming at the intersection between the cell holding surface 11 and the first rib 13, the application nozzle for discharging the adhesive 14 may be elongated so as to reach the application portion. In this case, in order to eject the adhesive 14 from the application nozzle, the application device needs to apply a high pressure to the adhesive 14. Such a coating device can be large and expensive. That is, the accuracy of the position where the adhesive 14 is applied may be a trade-off with the size or cost of the application device.

  When the cell holding surface 11 has the groove 16 and the recess 17, the adhesive 14 applied to the cell holding surface 11 tends to be accumulated in the groove 16 and the recess 17. In this case, the accuracy of the application position of the adhesive 14 by the application nozzle can be lowered. That is, the requirement for the application accuracy of the adhesive 14 to the application device can be alleviated. As a result, the applicator may not be large or expensive.

  The adhesive 14 may have a thickness corresponding to the depth of the groove 16 and the recess 17 by the adhesive 14 collecting in the groove 16 and the recess 17. By doing so, the thickness of the adhesive 14 can be easily controlled. The position where the adhesive 14 is first applied by the application nozzle has less influence on the thickness of the adhesive 14. As a result, only by applying the adhesive 14, the bonding strength between the cell 30 and the holder 10 can be easily secured.

  When the recess 17 is adjacent to the hole 12, the adhesive 14 applied to the cell holding surface 11 is unlikely to protrude to the hole 12. As a result, the electrode terminal of the cell 30 is less likely to be soiled by the adhesive 14 and is more likely to be joined to the bus bar.

  As a comparative example, a configuration in which a stepped portion is provided in a portion corresponding to the cell holding surface 11 of the holder 10 can be considered (see Patent Document 1). In the comparative example, a gap is formed between the steps, and the cell 30 can be joined by injecting the adhesive 14 into the gap. On the other hand, in the present embodiment, the bonding strength between the cell 30 and the holder 10 can be secured by the groove portion 16 and the recess portion 17 having a simple structure as compared with the comparative example.

  As shown in FIGS. 11A and 11B, the recess 17 may have a bottom surface 17a and a tapered surface 17c. In other words, the side surface 17b of FIG. 10 (B) may have a tapered shape. The tapered surface 17c may intersect the bottom surface 17a at a predetermined angle. The predetermined angle may be obtuse. When the concave portion 17 has the tapered surface 17 c, air is less likely to be accumulated at the intersection of the bottom surface 17 a and the tapered surface 17 c when the adhesive 14 is applied to the concave portion 17. As a result, the bonding strength between the cell 30 and the holder 10 can be easily secured.

  As shown in FIGS. 12A and 12B, the recess 17 may have a bead 18 on the bottom surface 17a. The bead 18 is shown as substantially rectangular, but is not limited to this and may have other shapes. The recess 17 may have a third rib on the bottom surface 17a. As shown in FIGS. 13A and 13B, the recess 17 may have a boss 19 on the bottom surface 17a. The bosses 19 may be formed by embossing. The bosses 19 are illustrated as being substantially circular, but are not limited thereto, and may have other shapes. The bead 18, the boss 19, and the third rib are collectively referred to as a convex portion. In other words, the recess 17 may have a protrusion on the bottom surface 17a. By the concave portion 17 having the convex portion on the bottom surface 17 a, the influence of the flatness of the cell holding surface 11 on the bonding strength between the cell 30 and the holder 10 can be reduced. As a result, the bonding strength between the cell 30 and the holder 10 can be easily secured.

  The convex portion may have a shape extending in the Y-axis direction. In other words, the projections may be shaped to extend in the longitudinal direction of the cap surface 304. For example, the boss 19 may be oval or oval. By the convex portion being shaped so as to extend in the longitudinal direction of the cap surface 304, variation in flatness of the cell holding surface 11 can be reduced. As a result, the bonding strength between the cell 30 and the holder 10 can be easily secured.

  As shown in FIG. 14, the recess 17 may have an embossed shape on the bottom surface 17 a. The emboss shape may be formed by emboss processing of the bottom surface 17a. Since the concave portion 17 has an embossed shape on the bottom surface 17 a, the thickness of the adhesive 14 can be easily secured, and the bonding effect between the cell 30 and the holder 10 can be improved by the anchor effect.

  According to the battery assembly 1 of the present disclosure, the cell 30 can be stably joined by the holder 10 having a relatively simple structure.

  Although one embodiment according to the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various changes or modifications based on the present disclosure. Therefore, it should be noted that these variations or modifications are included in the scope of the present disclosure. For example, the functions and the like included in each means can be rearranged so as not to be logically contradictory, and it is possible to combine or divide a plurality of means into one.

DESCRIPTION OF SYMBOLS 1 assembled battery 10 holder 11 cell holding surface 12 hole part 13 1st rib 14 adhesive 15 safety valve hole 16 groove part 17 recessed part 17a bottom surface 17b side surface 17c tapered surface 18 bead 19 boss 20 case 21 bottom surface 22 second rib 33, 34, 35 cells 301, 311, 321, 331, 341, 351 Positive terminals 302, 312, 322, 332, 342, 352 Negative terminals 303 Safety valve 304 Cap surface 305 Back surface 306 Flat surface 307 Side surface 40 Total minus terminal bus bar 41, 42, 43, 44 inter-cell bus bar 45 total plus terminal bus bar 50 insulation sheet

Claims (5)

A plurality of cells having a cap surface on which a pair of electrode terminals are provided;
And a holder for holding the plurality of cells on the cap surface,
The holder includes a hole through which the pair of electrode terminals can be inserted, a rib located between the cells, a groove located on both sides of the rib, and a recess located between the pair of holes Have and
The cell is bonded to the holder with an adhesive applied to the groove and the recess.
Battery pack.   The assembled battery according to claim 1, wherein a side surface of the recess has a tapered shape.   The assembled battery according to claim 1, wherein the recess has a protrusion on a bottom surface.   The assembled battery according to claim 3, wherein the convex portion extends in a longitudinal direction of the cap surface.   The assembled battery according to any one of claims 1 to 4, wherein the concave portion has an embossed shape on a bottom surface.