JP2013235728A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of liquid junction via a bolt for fastening a battery module.SOLUTION: A pair of end plates 13 are overlapped with both ends of a component obtained by alternately laminating a plurality of battery cells 11 and a plurality of holders 12 made of an insulating material, and a conductive bolt 14 penetrating through through-holes formed at abutting parts of the end plates 13 and the holders 12 is fastened to the end plates 13 to assemble a battery module. A waterproof structure part waterproofing the bolt has a covering part 12d protruding from an abutting surface 12b of the abutting part 12a of one holder 12 to cover an outer peripheral surface of the bolt 14. Since the covering part 12d fits the inside of the through-hole 12f opened to an abutting surface 12c of the abutting part 12a of the other holder 12, dew condensation water generated on a surface of the battery cells 11 is blocked by the waterproof structure part to prevent it from reaching the bolt 14, and therefore, generation of liquid junction via the bolt 14 caused by the dew condensation water can be prevented.

Description

  The present invention includes a plurality of battery cells to be stacked, a plurality of holders made of an insulating material sandwiched between the battery cells and butted against each other at a butting portion, and both ends of the battery cells and the holder in the stacking direction. The present invention relates to a battery module including a pair of end plates that are overlapped with each other and a conductive restraining shaft that is fastened to the end plate through a through hole formed in a butting portion of the holder.

  A plurality of batteries and a plurality of battery holders made of a non-conductive material are alternately stacked, a pair of end plates are overlapped on both ends in the stacking direction, and conductive restraint bolts penetrating through holes formed in the battery holder Patent Document 1 below discloses a battery assembly in which a battery, a battery holder, and an end plate are integrated by fastening both ends to a pair of end plates.

JP 2002-042753 A

  By the way, the battery cells that make up such a battery module generate heat when charging / discharging and the temperature rises, and when charging / discharging stops, the temperature decreases, so that moisture in the air condenses on the surface of the battery cell when the temperature drops. Condensation water may be generated. Further, when the battery cell is left in a low temperature environment, condensed water may be generated. When the condensed water flows from the surface of the battery cell to the metal part of the battery module, a phenomenon (liquid junction) may occur in which the terminal of the battery cell is short-circuited to the vehicle body frame or the like via the metal part of the battery module.

  In the above conventional one, the conductive restraint bolt penetrates the inside of the through hole of the non-conductive battery holder, but the condensed water generated in the battery cell enters the gap between the abutting surfaces of the adjacent battery holders. Then, there is a possibility that the terminal of the battery cell may have a liquid junction with the vehicle body frame through the restraint bolt and the end plate.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to prevent a liquid junction from being generated through a constraining shaft of a battery module.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of battery cells to be stacked and an insulating material sandwiched between the battery cells and abutted against each other at a butting portion are provided. A plurality of holders, a pair of end plates overlaid at both ends of the battery cell and the stacking direction of the holders, and conductive restraints that are fastened to the end plates through through holes formed in the butted portions of the holders A battery module including a shaft is proposed, wherein the restraining shaft is waterproofed by a waterproof structure.

  According to the invention described in claim 2, in addition to the configuration of claim 1, the waterproof structure portion projects from the abutting surface of the abutting portion of one of the holders and covers the outer peripheral surface of the constraining shaft. There is proposed a battery module including a cover portion, and the cover portion is fitted into the through-hole opened in the butting surface of the butting portion of the other holder.

  According to a third aspect of the present invention, in addition to the configuration of the second aspect, a battery module is proposed in which the cover portion is tapered toward the front end side.

  According to the invention described in claim 4, in addition to the structure of claim 3, the cover part is formed of an elastic body made of an insulating material, and the diameter of the base end part of the cover part is A bulging portion that is larger than the diameter of the through-hole into which the base end portion is fitted and bulges outward in the radial direction is sandwiched between the two butted surfaces facing each other. A battery module is proposed.

  According to the invention described in claim 5, in addition to the configuration of claim 4, the battery module is characterized in that the radially outer end of the bulging portion protrudes outward from the outer edge of the abutting surface. Proposed.

  According to the invention described in claim 6, in addition to the configuration of any one of claims 3 to 5, the cover portion is provided on one surface in the stacking direction of the holder, A battery module is proposed in which the constraining shaft includes a bolt having a head portion and a shaft portion, and the shaft portion is inserted from the other surface in the stacking direction of the holder.

  According to the invention described in claim 7, in addition to the configuration of any one of claims 2 to 6, the position of the butting surface in the stacking direction is the side surface of the battery cell facing the butting surface. A battery module is proposed which is characterized by facing the above.

  The first through hole 12e and the second through hole 12f of the embodiment correspond to the through hole of the present invention, and the bolt 14 of the embodiment corresponds to the restraining shaft of the present invention.

  According to the configuration of claim 1, a plurality of battery cells and a plurality of holders made of an insulating material are alternately stacked, and a pair of end plates are overlapped on both ends, and a through-hole formed in a butt portion of the end plate and the holder The battery module is assembled by fastening the conductive constraining shaft passing through the end plate. Since the constraining shaft is waterproofed by the waterproof structure, the condensed water generated on the surface of the battery cell is blocked by the waterproof structure to prevent it from reaching the constraining shaft, and a liquid junction is generated via the constraining shaft due to the dew condensation water. Can be prevented beforehand.

  Moreover, according to the structure of Claim 2, the waterproof structure part is provided with the cover part which protrudes from the butt | matching surface of the butt | matching part of one holder, and covers the outer peripheral surface of a restraint shaft, and a cover part butt | matches the butt | matching part of the other holder Since it fits in the inside of the through-hole opened to a surface, the waterproofness of a restraint shaft is securable by comprising a labyrinth with a cover part and a through-hole, and making it hard to flow in condensed water.

  According to the third aspect of the present invention, since the cover portion is tapered toward the front end side, the cover portion can be easily fitted into the through hole, and the assemblability of the battery module is improved.

  According to the configuration of claim 4, the cover portion is made of an elastic body made of an insulating material, and the diameter of the base end portion of the cover portion is larger than the diameter of the through hole into which the base end portion is fitted. Therefore, when the cover portion is fitted into the through hole, the base end portion of the cover portion bulges radially outward to form a bulge portion, and the bulge portion is sandwiched between two facing surfaces facing each other. By exhibiting the sealing effect, the waterproof property of the restraint shaft is further enhanced.

  According to the fifth aspect of the present invention, since the radially outer end of the bulging portion of the cover portion protrudes outward from the outer edge of the abutting surface, the sealing effect by the bulging portion can be further enhanced.

  According to the configuration of claim 6, the cover portion of the butting portion is provided on one surface in the stacking direction of the holder, and the shaft portion of the constraining shaft including the bolt having the head portion and the shaft portion is the other in the stacking direction of the holder. Therefore, it is possible to prevent the tip end of the bolt shaft portion from hitting the tip end of the tapered taper and damaging it.

  Moreover, according to the structure of Claim 7, since the stacking direction position of the butting surface of the butting portion of the holder faces the side surface of the battery cell facing the butting surface, from the main surface of the battery cell in which a large amount of condensed water is likely to occur. By keeping the abutting surface as far as possible, the waterproof property of the restraint shaft can be further enhanced.

The perspective view of a battery module. (First embodiment) The exploded perspective view of a battery module. (First embodiment) FIG. 3 is an enlarged view of part 3 of FIG. 2. (First embodiment) FIG. 4 is a sectional view taken along line 4-4 of FIG. (First embodiment) The enlarged view of the butting | matching part of a holder. (Second Embodiment) The figure corresponding to FIG. (Third embodiment)

First embodiment

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, a battery module M used as a power supply device for an electric vehicle or a hybrid vehicle includes a predetermined number (12 in the embodiment) of battery cells 11 stacked in the stacking direction. . Each battery cell 11 is formed in a rectangular parallelepiped shape, a pair of main surfaces 11a, 11a facing each other, a pair of side surfaces 11b, 11b facing each other orthogonal to the main surfaces 11a, 11a, and a main surface 11a. , 11a and side surfaces 11b, 11b, and a top surface 11c and a bottom surface 11d that are opposed to each other perpendicularly, and positive and negative electrodes 11e, 11e are provided on the top surface 11c.

  The main surfaces 11a of the twelve battery cells 11 and 13 square plate-shaped holders 12 made of an insulating synthetic resin are alternately stacked, and the two holders 12 at both ends in the stacking direction. , 12 are superposed on a pair of end plates 13, 13 made of conductive metal. In this state, the bolt holes 13a at the four corners of the pair of end plates 13 and 13 and the butted portions 12a at the four corners of the holders 12 are made of four bolts made of conductive metal. 14 penetrates in the stacking direction. Then, in a state where the head portion 14a of each bolt 14 is in contact with the outer surface of one end plate 13, the nut 15 that is screwed into the female screw at the tip of the shaft portion 14b is in contact with the outer surface of the other end plate 13, The end plates 13, 13, the battery cells 11 and the holders 12 are fastened in the stacking direction.

  3 and 4, the shape of the butted portion 12a of the two holders 12 and 12 positioned at both ends in the stacking direction among the twelve holders 12 is 10 holders 12 on the inner side in the stacking direction. Since the shape of the butted portions 12a is slightly different, the structure of the butted portions 12a of the latter holders 12 will be described as a representative.

  Each abutting portion 12a includes a pair of abutting surfaces 12b and 12c that come into contact with the adjacent abutting portion 12a, and a truncated conical covering portion 12d that tapers out from one abutting surface 12b projects. The abutting portion 12a includes a first through hole 12e and a second through hole 12f through which the bolt 14 passes, and the first through hole 12e extending to the inside of the cover portion 12d is substantially equal to the diameter of the shaft portion 14b of the bolt 14. Although it has a constant diameter, the second through-hole 12f is larger in diameter than the shaft 14b of the bolt 14 and tapers inwardly from the other butted surface 12c. The outer peripheral surface of the cover portion 12d and the inner peripheral surface of the second through hole 12f have the same shape so as to be in close contact with each other.

  The positions in the stacking direction of the butted surfaces 12b and 12c generally correspond to the center position C in the stacking direction of the side surface 12b of the battery cell 11 (see FIG. 4A). That is, the positions of the butting surfaces 12b and 12c are set to positions farthest from the main surfaces 11a and 11a of the battery cell 11.

  Of the two holders 12 and 12 located at both ends, each butted portion 12a of the holder 12 on the nut 15 side does not include the second through hole 12f, and the holder 12 on the head 14a side of the bolt 14 is not provided. Each butting portion 12a (details not shown) is slightly different from the other butting portions 12a in that the covering portion 12d is not provided.

  Next, the operation of the first embodiment of the present invention having the above configuration will be described.

  As shown in FIG. 4, when the end plates 13, 13, the battery cells 11, and the holders 12 are stacked, one of the butted portions 12 a among the butted portions 12 a and 12 of the two adjacent holders 12 and 12. When the cover portion 12d is fitted into the second through hole 12f of the other butted portion 12a, the two adjacent holders 12 and 12 are positioned with respect to each other. As a result, the first through holes 12e of the twelve holders 12 are connected in series, and the four bolts 14 can pass through the first through holes 12e. In this state, the butted surfaces 12b and 12c of the two adjacent butted portions 12a and 12a are in close contact with each other, and a cover is provided between the outer edge of the butted surfaces 12b and 12c and the outer peripheral surface of the shaft portion 14b of the bolt 14. A long labyrinth formed by the contact surfaces of the outer peripheral surface of the portion 12d and the inner peripheral surface of the second through hole 12f is formed.

  Even if moisture in the air condenses on the surface of the battery cells 11 to generate condensed water, and the condensed water flows and reaches the outer edges of the abutting surfaces 12b and 12c, the condensed water is blocked by the labyrinth and is bolted. 14 cannot reach the outer peripheral surface of the shaft portion 14b, and the electrodes 11e of the battery cells 11 ... are liable to liquid-contact with the body frame or the like via the dew condensation water, the bolts 14 ... and the end plates 13, 13. Can be prevented.

  Further, since the cover portion 12d of the abutting portion 12a is tapered toward the tip, the operation of inserting the tip into the second through hole 12f is facilitated, and the assemblability of the battery module M is improved. Moreover, since the stacking direction positions of the butting surfaces 12b and 12c of the butting portions 12a and 12a substantially correspond to the stacking direction center position C (see FIG. 4A) of the side surface 11b of the battery cell 11, a large amount of condensed water is present. If the butted surfaces 12b and 12c are as far away as possible from the main surfaces 11a and 11a of the large-area battery cell 11 that easily occurs, the waterproofness of the bolts 14 can be further enhanced.

Second embodiment

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, the cover 12d of the butting portion 12a of the holder 12 is made of an elastic body such as rubber, and is bonded to the butting surface 12b of the butting portion 12a by bonding or the like. The diameter D1 of the base end of the cover portion 12d is set to be slightly larger than the diameter D2 of the open end to the butting surface 12c of the second through hole 12f into which the cover portion 12d is fitted.

  As a result, when the cover portion 12d is fitted into the second through-hole 12f and fastened with the bolt 14, the base end portion of the cover portion 12d cannot be completely fitted into the second through-hole 12f. It becomes an annular bulging portion 12g and protrudes radially outward and is sandwiched between the butted surfaces 12b and 12c of the adjacent two butted portions 12a and 12a. The annular bulging portion 12g made of elastic rubber functions as a seal member such as an O-ring. Therefore, the gap between the abutting surfaces 12b and 12c is effectively sealed, and the dew condensation water forms on the shaft portion 14b of the bolt 14. Reaching the surface can be prevented more reliably. At this time, as shown in an enlarged manner in the circle of FIG. 5A, the sealing effect is improved by projecting at least a part of the tip of the bulging portion 12g outward from the outer edges of the butted surfaces 12b and 12c. To do.

  As described above, according to the second embodiment, synergy between the bulging portion 12g of the cover portion 12d and the labyrinth formed between the outer peripheral surface of the cover portion 12d and the inner peripheral surface of the second through hole 12f. With the effect, the occurrence of liquid junction can be prevented more reliably.

Third embodiment

  Next, a third embodiment of the present invention will be described with reference to FIG.

  In the first embodiment, the shaft portion 14b of the bolt 14 passes through each holder 12 from the first through hole 12e side to the second through hole 12f side. However, the third embodiment The insertion direction is reversed, and the insertion is made from the second through hole 12f side to the first through hole 12e side.

  In the first embodiment, when the tip of the shaft portion 14b of the bolt 14 is inserted into the first through hole 12e, the tip may collide with the thin portion at the tip of the cover portion 12d and be damaged. According to the third embodiment, since there is no such concern, the insertion operation of the bolt 14 is facilitated and the assembling property is improved. Moreover, since there is little possibility that a thin part will be damaged, it can prevent that the waterproofness of the cover part 12d falls.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the structure of the waterproof structure is not limited to the embodiment, and the restraint shaft itself may be covered with an insulating film such as a synthetic resin to be electrically insulated.

  Moreover, the restraint shaft of this invention is not limited to the volt | bolt 14 of embodiment, The rod-shaped member etc. which formed the internal thread in the both ends may be sufficient.

11 battery cell 11b side surface 12 holder 12a butt portion 12b butt surface 12c butt surface 12d cover portion 12e first through hole (through hole)
12f Second through hole (through hole)
12g bulge 13 end plate 14 bolt (restraint shaft)
14a Head portion 14b Shaft portion D1 Diameter of the base end portion of the cover portion D2 Diameter of the through hole

Claims (7)

A plurality of battery cells (11) to be stacked, a plurality of holders (12) made of an insulating material sandwiched between the battery cells (11) and abutted against each other at a butting portion (12a), and the battery cells (11) and a pair of end plates (13) superimposed on both ends in the stacking direction of the holder (12), and through holes (12e, 12f) formed in the butted portion (12a) of the holder (12). A battery module comprising a conductive constraining shaft (14) fastened to the end plate (13).
The battery module, wherein the constraining shaft (14) is waterproofed by a waterproof structure.   The waterproof structure portion includes a cover portion (12d) that protrudes from the abutting surface (12b) of the abutting portion (12a) of one of the holders (12) and covers the outer peripheral surface of the restraining shaft (14). The part (12d) is fitted in the inside of the through hole (12f) opened in the butting surface (12c) of the butting part (12a) of the other holder (12). The battery module as described.   The battery module according to claim 2, wherein the cover portion (12 d) is tapered toward the distal end side.   The cover portion (12d) is made of an elastic body made of an insulating material, and the diameter (D1) of the base end portion of the cover portion (12d) is the through hole (12f) into which the base end portion is fitted. A bulging portion (12g) that is larger than the diameter (D2) of the base end and bulges outward in the radial direction is sandwiched between the two butting surfaces (12b, 12c) facing each other. The battery module according to claim 3.   The battery module according to claim 4, wherein a radially outer end of the bulging portion (12g) protrudes outward from an outer edge of the abutting surface (12b, 12c).   The cover portion (12d) is provided on one surface in the stacking direction of the holder (12), and the constraining shaft (14) includes a bolt (14) having a head portion (14a) and a shaft portion (14b). The battery module according to any one of claims 3 to 5, wherein the shaft portion (14b) is inserted from the other surface in the stacking direction of the holder (12).   The position in the stacking direction of the butting surfaces (12b and 12c) faces the side surface (11b) of the battery cell (11) facing the butting surfaces (12b and 12c). The battery module according to any one of the above.

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