JP6915358B2 - Battery module - Google Patents

Description

The present invention relates to a battery module.

As a conventional battery module, for example, there is a battery module described in Patent Document 1. In this conventional battery module, an array formed by arranging a plurality of battery cells, a pair of end plates sandwiching the array in the arrangement direction of the battery cells, and the end plates are connected to each other to apply a restraining load to the array. It is configured to include a restraining member. The restraint member includes a connecting rod inserted into an insertion hole provided in the end plate and nuts screwed to both ends of a connecting bolt protruding to the outside of the end plate.

Japanese Unexamined Patent Publication No. 2001-236937

In the battery module as described above, for example, when an impact load due to vibration acts on the restraining member, it is conceivable that the position of the connecting rod in the insertion hole of the end plate fluctuates momentarily. Normally, the insertion hole of the end plate has an inner diameter that is one size larger than the outer diameter of the connecting rod from the viewpoint of ease of assembling the connecting rod. Therefore, if the position of the connecting rod fluctuates and the threaded portion formed on the connecting rod interferes with the inner wall of the insertion hole (particularly the inner wall on the outer opening end side), an excessive load is applied to the threaded portion to connect the rod. It may cause deformation or breakage of the rod.

The present invention has been made to solve the above problems, and provides a battery module capable of preventing interference between the threaded portion of the connecting rod and the inner wall of the insertion hole of the end plate even when an impact load due to vibration is applied. The purpose is.

The battery module according to one aspect of the present invention includes an array formed by arranging a plurality of battery cells, a pair of end plates sandwiching the array in the arrangement direction of the battery cells, and a connecting rod for connecting the pair of end plates. The end plate has an insertion hole through which the connecting rod is inserted, and the connecting rod has a cylindrical portion having a female screw on one end side and a shaft portion having a screw portion on the tip side. A male screw having a male screw and a shaft portion inserted into the insertion hole is screwed into a female screw of a cylindrical portion arranged between a pair of end plates to connect the connecting rod and one end plate. The part is composed.

In this battery module, in the joint portion, a male screw shaft portion is passed through an insertion hole of one end plate, and a screw portion provided on the tip side of the shaft portion is arranged between a pair of end plates. It is screwed into the female screw. According to this configuration, the position of the male screw threaded portion in the insertion hole can be moved closer to the inner opening end side of the insertion hole, so that the inner wall on the outer opening end side of the insertion hole and the male screw threaded portion are aligned. It becomes non-opposite. Therefore, even when an impact load due to vibration is applied, the threaded portion does not interfere with the inner wall on the outer opening end side of the insertion hole, and an excessive load can be prevented from being applied to the threaded portion, thus suppressing deformation and breakage of the connecting rod. can.

Further, an elastic member may be arranged between one end plate and the array. By arranging the elastic member, it is possible to suppress deformation and breakage of the end plate and the connecting rod when the battery cell expands. On the other hand, when the elastic member is arranged, one end plate located on the elastic member side is connected when an impact load due to vibration is applied as compared with the other end plate located on the opposite side of the elastic member. It is considered that the amount of variation of the end plate with respect to the rod becomes large. Therefore, by applying the coupling portion to the coupling between one end plate located on the elastic member side and the connecting rod, deformation or breakage of the connecting rod when an impact load due to vibration is applied can be suitably suppressed.

Further, the pair of end plates have a holding surface to which the connecting rods are connected and an external fixing piece provided at the edge of the holding surface, and the connecting rods are held at a position closer to the external fixing side. It has a first connecting rod that connects the surfaces and a second connecting rod that connects the holding surfaces at a position separated from the external fixing piece as compared with the first connecting rod, and the connecting portion has. , At least may be applied to the connection between the second connecting rod and one end plate. When the battery module is fixed to the outside via the external fixing piece, the amount of fluctuation of the end plate with respect to the connecting rod when an impact load due to vibration is applied is considered to increase as the distance from the external fixing piece, which is the fixed position, increases. .. Therefore, by applying the coupling portion to the coupling between at least one end plate and the second connecting rod, deformation or breakage of the connecting rod when an impact load due to vibration is applied can be suitably suppressed.

Further, in the joint portion, one end plate may be sandwiched between the end surface on one end side of the cylindrical portion and the seating surface of the male screw. In this case, it is possible to suppress the fluctuation of the end plate with respect to the connecting rod when an impact load due to vibration is applied.

Further, the male screw may be a stepped bolt in which a large diameter portion larger than the diameter of the screw portion is provided on the base end side of the shaft portion. In this case, rattling of the connecting rod in the insertion hole can be suppressed.

Further, the radius of the large diameter portion may be substantially the same as the shortest distance from the inner wall of the insertion hole to the center of the female screw when the insertion hole is viewed from the opening side. In this case, the rattling of the connecting rod in the insertion hole can be suppressed more reliably.

According to the present invention, it is possible to prevent interference between the threaded portion of the connecting rod and the inner wall of the insertion hole of the end plate even when an impact load due to vibration is applied.

It is a schematic block diagram which shows one Embodiment of a battery module. It is an enlarged sectional view of the main part which shows the joint part of the end plate and the restraint member in the conventional example. It is an enlarged sectional view of the main part which shows the joint part of the end plate and the connecting rod in this embodiment. It is an enlarged cross-sectional view of the main part which shows the joint part of the end plate and the connecting rod in the modification. It is a figure which shows an example of the design method of a large diameter part.

Hereinafter, preferred embodiments of the battery module according to one aspect of the present invention will be described in detail with reference to the drawings.
[Overall configuration of battery module]

FIG. 1 is a schematic configuration diagram showing an embodiment of a battery module. In the example shown in the figure, the battery module 1 is fixed to the inner wall side of the housing K with a heat conductive member (not shown) interposed therebetween. The battery module 1 includes an array 2 of battery cells 7, an elastic member 3, a middle plate 4, end plates 5 (5A, 5B), and a connecting rod 6.

The array 2 has a plurality of battery cells 7 arranged in a predetermined direction. The battery cell 7 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. Adjacent battery cells 7 and 7 are attached to each other with, for example, double-sided tape. Each battery cell 7 may be held by a resin cell holder. Further, each battery cell 7 may be provided with a heat transfer plate.

Each battery cell 7 contains, for example, an electrode assembly and an electrolytic solution in a hollow case having a substantially rectangular parallelepiped shape. A pair of electrode terminals (not shown) are provided on the top surface of the case so as to be separated from each other. One of the electrode terminals is a positive electrode terminal connected to the positive electrode of the electrode assembly, and the other of the electrode terminals is a negative electrode terminal connected to the negative electrode of the electrode assembly. The adjacent battery cells 7 and 7 are arranged so that the positive electrode terminal and the negative electrode terminal are adjacent to each other. The adjacent battery cells 7 and 7 are electrically connected in series by connecting the adjacent positive electrode terminal and the negative electrode terminal with a bus bar member.

The elastic member 3 is used for the purpose of preventing damage to the battery cell 7, the end plate 5, and the connecting rod 6 due to a restraining load when the battery cell 7 expands. The elastic member 3 is formed in a rectangular plate shape by, for example, a urethane rubber sponge. The elastic member 3 is arranged between the array 2 and one end plate 5A. Examples of other forming materials for the elastic member 3 include ethylene propylene diene rubber (EPDM), chloroprene rubber, and silicon rubber. The elastic member 3 is not limited to rubber, and may be a spring material or the like.

The middle plate 4 is, for example, a plate-shaped member made of resin or metal. The middle plate 4 has a substantially rectangular plate shape corresponding to the planar shape of the battery cells 7 viewed from the arrangement direction, and is arranged between the battery cells 7 located at one end in the arrangement direction and the elastic member 3. ing. By arranging the middle plate 4 between the array body 2 and the elastic member 3, the variation in the load applied from the elastic member 3 to each battery cell 7 is suppressed. An insertion hole 8 through which the connecting rod 6 is inserted is provided at the edge of the middle plate 4. The inner diameter of the insertion hole 8 is one size larger than the outer diameter of the connecting rod 6.

The end plate 5 is, for example, a metal plate-shaped member. Like the middle plate 4, the end plate 5 has a substantially rectangular plate shape corresponding to the shape of the battery cells 7 when viewed from the arrangement direction. One end plate 5A is arranged so as to abut the elastic member 3. The other end plate 5B is arranged so as to abut the battery cell 7 located at the other end in the arrangement direction. When a resin cell holder is attached to the battery cell 7, the end plate 5B and the battery cell 7 are electrically insulated by the cell holder. When the cell holder is not used, an insulating member may be interposed between the end plate 5B and the battery cell 7.

The end plate 5 has a holding surface 11 to which the connecting rod 6 is connected, and an external fixing piece 12 provided at one edge of the holding surface 11. The sandwiching surface 11 is a surface that sandwiches the array body 2 and the elastic member 3. The edge of the sandwiching surface 11 is provided with an insertion hole 13 through which the connecting rod 6 is inserted so as to correspond to the insertion hole 8 at the edge of the middle plate 4. The inner diameter of the insertion hole 13 is one size larger than the outer diameter of the connecting rod 6.

The external fixing piece 12 is a portion used for fixing the battery module 1 and the external member (here, the housing K). The external fixing piece 12 projects from one edge of the holding surface 11 at a substantially right angle to the holding surface 11. The external fixing piece 12 is provided with an insertion hole 14 through which the fixing bolt B is inserted. The battery module 1 is firmly fixed to the housing K by screwing the fixing bolt B passed through the insertion hole 14 into the bolt hole provided in the housing K.

The connecting rod 6 is a metal member that connects the end plates 5A and 5B to each other. The connecting rod 6 is fastened to the end plates 5A and 5B, respectively, in a state of being passed through the insertion hole 13 of the end plate 5 and the insertion hole 8 of the middle plate 4. As a result, the battery cell 7, the elastic member 3, and the middle plate 4 are sandwiched and unitized, and the battery cell 7, the elastic member 3, and the middle plate 4 are designated via the end plates 5A and 5B. The restraining load of is added.

In the present embodiment, in the end plate 5 and the middle plate 4, the insertion holes 13 and the insertion holes 8 are provided at the edge portion on the side of the external fixing piece 12 and the edge portion at a position facing the edge portion, respectively. .. Therefore, the connecting rod 6 is external to the first connecting rod 6A that connects the holding surfaces 11 and 11 of the end plates 5A and 5B at a position closer to the external fixing piece 12 and the first connecting rod 6A. It is composed of a second connecting rod 6B that connects the holding surfaces 11 and 11 of the end plates 5A and 5B at positions separated from the fixing piece 12.
[Structure of the joint between the end plate and the connecting rod]

Next, the configuration of the joint portion between the end plate 5 and the connecting rod 6 described above will be described in more detail.

First, a conventional example of the joint portion will be described. FIG. 2 is an enlarged cross-sectional view of a main part showing a joint portion between the end plate and the restraint member in the conventional example. As shown in the figure, in the conventional example, the restraint bolt 101 and the nut 102 are used as the restraint members constituting the joint portion 100. A screw portion 104 is formed at the tip of the shaft portion 103 of the restraint bolt 101. The tip of the restraint bolt 101 is inserted into the insertion hole 105 so that the threaded portion 104 protrudes to the outside of one end plate 106. The nut 102 is screwed into a threaded portion 104 protruding from one end plate 106. Although not shown, the head of the restraint bolt 101 is connected to the outside of the other end plate.

In such a joint portion 100, when an impact load due to vibration acts on the restraint member, it is conceivable that the position of the restraint bolt 101 in the insertion hole 105 of the end plate 106 changes momentarily. Normally, the insertion hole 105 of the end plate 106 has an inner diameter that is one size larger than the outer diameter of the shaft portion 103 and the screw portion 104 of the restraint bolt 101 from the viewpoint of ease of assembling the restraint bolt 101. Therefore, for example, as shown by the alternate long and short dash line in FIG. 2, if the position of the restraint bolt 101 fluctuates and the screw portion 104 interferes with the inner wall of the insertion hole 105 (particularly the inner wall on the outer opening end 105b side), the screw An excessive load is applied to the portion 104, which may cause deformation or breakage of the restraint bolt 101.

On the other hand, FIG. 3 is an enlarged cross-sectional view of a main part showing a joint portion between the end plate and the connecting rod in the present embodiment. In the example of the figure, a connecting portion 21 of one end plate 5A that abuts on the elastic member 3 and a second connecting rod 6B that is arranged at a position separated from the external fixing piece 12 is shown. As shown in FIG. 3, the second connecting rod 6B has a cylindrical portion 22 provided with a female screw 27 on one end side, and a shaft portion 25 provided with a screw portion 26 only on the head portion 24 and the tip end side. It has a male screw 23.

The cylindrical portion 22 of the second connecting rod 6B has an outer diameter larger than the inner diameter of the insertion hole 13 of the holding surface 11 in the end plate 5A, and is arranged between the end plates 5A and 5B. The one end surface 22a of the cylindrical portion 22 is abutted against the peripheral portion of the inner opening end 13a of the insertion hole 13 on the inner surface side of the holding surface 11 of the end plate 5A. The head 24 of the male screw 23 is arranged on the outside of the end plate 5A. The shaft portion 25 of the male screw 23 is inserted into the insertion hole 13 from the outside of the end plate 5A, and the screw portion 26 on the tip end side of the shaft portion 25 protrudes from the inner opening end 13a of the insertion hole 13 and is the female of the cylindrical portion 22. It is screwed into the screw 27.

By screwing the male screw 23 into the female screw 27 of the cylindrical portion 22, the peripheral portion of the insertion hole 13 in the end plate 5A is sandwiched from both sides by the seat surface 23a of the male screw 23 and the one end surface 22a of the cylindrical portion 22. A joint portion 21 is formed between the end plate 5A and the second connecting rod 6B. As described above, in the male screw 23, the screw portion 26 is provided only on the tip end side of the shaft portion 25, and the base end side of the shaft portion 25 is a cylindrical portion in which the screw portion 26 is not provided. .. Therefore, the inner wall of the insertion hole 13 on the inner opening end 13a side faces the screw portion 26 of the male screw 23, while the inner wall of the insertion hole 13 on the outer opening end 13b side faces the shaft portion 25 of the male screw 23. (That is, it is in a state of facing (that is, a portion where the screw portion 26 is not provided).
[Action effect]

As described above, in the battery module 1, in the joint portion 21 between the end plate 5A and the second connecting rod 6B, the shaft portion 25 of the male screw 23 is passed through the insertion hole 13 of the end plate 5A, and the shaft portion 25 is passed. The screw portion 26 provided on the tip end side of the 25 is screwed into the female screw 27 of the cylindrical portion 22. According to such a configuration, the position of the screw portion 26 of the male screw 23 in the insertion hole 13 can be moved closer to the inner opening end 13a side, so that the inner wall and the male screw on the outer opening end 13b side of the insertion hole 13 can be moved. The screw portion 26 of the 23 is not opposed to the screw portion 26. Therefore, even when an impact load due to vibration is applied, the screw portion 26 does not interfere with the inner wall on the outer opening end 13b side of the insertion hole 13, and an excessive load can be prevented from being applied to the screw portion 26. Deformation and breakage can be suppressed.

In the present embodiment, the elastic member 3 is arranged between one end plate 5A and the array 2. Further, the coupling portion 21 having the above-described configuration is applied to the coupling between the end plate 5A abutting on the elastic member 3 and the connecting rod 6. By arranging the elastic member 3, it is possible to suppress deformation and breakage of the end plate 5 and the connecting rod 6 when the battery cell 7 expands. On the other hand, when the elastic member 3 is arranged, the end plate 5A located on the elastic member 3 side is more affected by the impact load due to vibration than the end plate 5B located on the opposite side of the elastic member 3. It is considered that the amount of fluctuation of the end plate 5 with respect to the connecting rod 6 becomes large. Therefore, by applying the coupling portion 21 to the coupling between the end plate 5A located on the elastic member 3 side and the connecting rod 6, deformation or breakage of the connecting rod 6 when an impact load due to vibration is applied is suitably suppressed. can.

In the present embodiment, the pair of end plates 5 and 5 have a holding surface 11 to which the connecting rod 6 is connected, and an external fixing piece 12 provided at the edge of the holding surface 11. Further, the connecting rod 6 is separated from the first connecting rod 6A that connects the holding surfaces 11 and 11 to each other at a position closer to the external fixing piece 12 and the external fixing piece 12 as compared with the first connecting rod 6A. It has a second connecting rod 6B that connects the holding surfaces 11 and 11 to each other at the positioned position. The coupling portion 21 is applied to the coupling between the second connecting rod 6B and the end plate 5A.

When the battery module 1 is fixed to the housing K via the external fixing piece 12, the amount of fluctuation of the end plate 5 with respect to the connecting rod 6 when an impact load due to vibration is applied is the external fixing piece 12 which is a fixed position. It is thought that the farther away from, the larger it becomes. Therefore, by applying the coupling portion 21 to the coupling between the end plate 5A and the second connecting rod 6B, deformation or breakage of the connecting rod 6 when an impact load due to vibration is applied can be suitably suppressed.

In the present embodiment, in the joint portion 21, the end plate 5A is sandwiched between the one end surface 22a of the cylindrical portion 22 and the seat surface 23a of the male screw 23. As a result, it is possible to suppress the fluctuation of the end plate 5 with respect to the connecting rod 6 when an impact load due to vibration is applied.
[Modification example of joint part]

FIG. 4 is an enlarged cross-sectional view of a main part showing a joint portion between the end plate and the connecting rod in the modified example. In the example of FIG. 4, similarly to FIG. 3, a joint portion between one end plate 5A in contact with the elastic member 3 and a second connecting rod 6B arranged at a position separated from the external fixing piece 12 is shown. ing. As shown in the figure, the joint portion 31 according to the modified example differs from the above embodiment in that the male screw 33 is a stepped bolt.

That is, in the second embodiment, in the male screw 33, a large diameter portion 37 larger than the diameter of the screw portion 36 is provided on the base end side of the shaft portion 35. The shaft portion 35 of the male screw 33 is inserted into the insertion hole 13 from the outside of the end plate 5A, and the screw portion 36 on the tip end side of the shaft portion 35 protrudes from the inner opening end 13a of the insertion hole 13 and is the female of the cylindrical portion 22. It is screwed into the screw 27. The inner wall of the insertion hole 13 is in a state of facing the peripheral surface of the large diameter portion 37 of the male screw 33 over substantially the entire area from the outer opening end 13b to the inner opening end 13a.

In such a second embodiment, substantially the entire inner wall of the insertion hole 13 is non-opposing to the threaded portion 36 of the male screw 33. Therefore, even when an impact load due to vibration is applied, the screw portion 36 does not interfere with the inner wall of the insertion hole 13 and an excessive load can be prevented from being applied to the screw portion 36, so that deformation or breakage of the connecting rod 6 can be suppressed. .. Further, since the large diameter portion 37 larger than the diameter of the screw portion 36 is located in the insertion hole 13, the distance between the inner wall of the insertion hole 13 and the peripheral surface of the large diameter portion 37 can be reduced, and the insertion hole 13 can be reduced. It is possible to suppress the rattling of the connecting rod 6 inside.

As shown in FIG. 5, it is conceivable that the female screw 27 is eccentric with respect to the center X of the insertion hole 13 due to manufacturing tolerances of the connecting rod 6, the end plate 5, the insertion hole 13, and the like. In this case, it is preferable to use a plurality of types of stepped bolts having different radii of the large diameter portion 37 as the male screw 33. Select the type of the male screw 33 so that the radius of the large diameter portion 37 substantially matches the shortest distance A from the inner wall of the insertion hole 13 to the center Y of the female screw 27 when the insertion hole 13 is viewed from the opening side. Therefore, the rattling of the connecting rod 6 in the insertion hole 13 can be suppressed more reliably.
[Other variants]

In the above embodiment, the coupling portions 21 and 31 applied to the coupling between the end plate 5A to which the elastic member 3 is in contact and the connecting rod 6 have been described, but the coupling portions 21 and 31 are in contact with the array 2 on the opposite side of the elastic member 3. The coupling between the end plate 5B and the connecting rod 6 may have any configuration. For example, the other end side of the connecting rod 6 may be a bolt head. Further, for example, the connection between the end plate 5B and the connecting rod 6 may have a configuration in which a nut is screwed into a screw portion formed at the other end of the connecting rod 6 (see FIG. 1). In this case, a double nut configuration in which two nuts are screwed into the threaded portion may be adopted. In the double nut configuration, looseness of the nut on the inside (end plate side) can be regulated by the nut on the outside (tip side of the screw portion).

The configuration of the coupling portions 21 and 31 may be applied to the coupling between the end plate 5B and the connecting rod 6. By applying the coupling portions 21 and 31 to both the connection between the end plate 5A and the connecting rod 6 and the connection between the end plate 5B and the connecting rod 6, the connecting rod 6 can be deformed when an impact load due to vibration is applied. Damage can be suppressed more reliably. The coupling portions 21 and 31 may be applied to the battery module 1 in which the elastic member 3 is not arranged.

In the above embodiment, the connecting portions 21 and 31 are applied to the connection between the second connecting rod 6B and the end plate 5 arranged at a position separated from the external fixing piece 12, but the connecting portions 21 and 31 are closer to the external fixing piece 12. The coupling portions 21 and 31 may be applied to the coupling between the first connecting rod 6A and the end plate 5 arranged at the position of. By applying the coupling portions 21 and 31 to both the coupling between the first connecting rod 6A and the end plate 5 and the coupling between the second connecting rod 6B and the end plate 5, when an impact load due to vibration acts. Deformation and breakage of the connecting rod 6 can be suppressed more reliably.

1 ... Battery module, 2 ... Arrangement, 3 ... Elastic member, 5 (5A, 5B) ... End plate, 6 (6A, 6B) ... Connecting rod, 7 ... Battery cell, 11 ... Holding surface, 12 ... For external fixing One piece, 13 ... Insertion hole, 21 ... Joint part, 22 ... Cylindrical part, 22a ... One end surface, 23 ... Male screw, 23a ... Seat surface, 25 ... Shaft part, 26 ... Screw part, 27 ... Female screw, 31 ... Bond Part, 33 ... Male screw, 35 ... Shaft part, 36 ... Screw part, 37 ... Large diameter part.

Claims (5)

An array consisting of multiple battery cells arranged together,
A pair of end plates that sandwich the array in the array direction of the battery cells,
A connecting rod for connecting the pair of end plates to each other is provided.
The end plate has an insertion hole through which the connecting rod is inserted.
The connecting rod has a cylindrical portion provided with a female screw on one end side and a male screw having a shaft portion provided with a threaded portion on the tip end side.
The male screw through which the shaft portion is inserted into the insertion hole is screwed into the female screw on one end side of the cylindrical portion arranged between the pair of end plates, whereby the connecting rod and one end plate are formed. The joint is composed of
An elastic member, which is rubber, is arranged between the one end plate and the array.
A battery module in which at a joint portion between the connecting rod and one end plate, the one end plate is sandwiched between the end surface on one end side of the cylindrical portion and the seating surface of the male screw. The pair of end plates have a holding surface to which the connecting rod is bonded and an external fixing piece provided at an edge of the holding surface.
The connecting rod has a first connecting rod that connects the holding surfaces to each other at a position closer to the external fixing piece, and the holding rod at a position separated from the external fixing piece as compared with the first connecting rod. It has a second connecting rod that connects the faces to each other,
The coupling portion, at least the second battery module according to claim 1, characterized in that applies to a connecting rod to the coupling with the one end plate. The battery module according to claim 1 or 2 , wherein the male screw is a stepped bolt having a large diameter portion larger than the diameter of the screw portion provided on the base end side of the shaft portion. The battery module according to claim 3 , wherein the radius of the large diameter portion substantially coincides with the shortest distance from the inner wall of the insertion hole to the center of the female screw when the insertion hole is viewed from the opening side. A female screw is further provided on the other end side of the cylindrical portion.
The male screw through which the shaft portion is inserted into the insertion hole is screwed into the female screw on the other end side of the cylindrical portion arranged between the pair of end plates, whereby the connecting rod and the other end plate are screwed. The joint with
Claims 1 to 4 in which the other end plate is sandwiched between the other end surface of the cylindrical portion and the seating surface of the male screw at the joint portion between the connecting rod and the other end plate. The battery module according to any one of the above.

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