JP2009026607A - Power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim weight reduction of a bolt fixing section in a power supply system wherein battery modules are piled up via a spacer. <P>SOLUTION: The power supply system 10 is fixed with bolt-fastening by piling two sets of battery modules 1, and has a spacer 6 which is brought into contact with a side surface of the first-step battery module 1 and is inserted in the load direction of the second-step battery module 1. The spacer 6 is a metal member folded down in parallel in the load direction, a seating surface of a bolt 4 is arranged to overlap with an end face of the spacer 6, and the end face of the spacer 6 is a shorter face of at least two faces of folded-down faces. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply system, and more particularly to a power supply system in which a plurality of battery modules are stacked and fixed by bolt fastening.

  Conventionally, when a power supply system is configured by stacking a certain amount of heavy objects, such as a battery module in which a plurality of unit cells are connected and accommodated, in order to ensure structural strength after fixing the first stage battery module. A method is used in which a pedestal is attached to the top and a second-stage battery module is placed and fixed thereon. The base has the same strength as the base that fixes the first-stage battery module, and is heavy and bulky for the function of placing and fixing the second-stage battery module. It was a thing.

  The power supply system is also mounted on a moving body such as a vehicle. In such applications, an increase in weight reduces the apparent weight output density seen from the vehicle. Since the main function of the power supply system is charge / discharge of electricity, the placement / fixation, which is the function of the gantry, is only a secondary function. Therefore, providing a pedestal when stacking and fixing a plurality of modules (in the case of configuring a power supply system), the pedestal has a high proportion of the total weight and constitutes a wasteful part. For this reason, a structure has been proposed in which the spacers are stacked between the battery modules (see, for example, Patent Document 1).

JP 2007-165164 A

  Although the technique of the above-mentioned patent document 1 has achieved weight reduction by using a spacer instead of a gantry, when bolting the upper battery module, the bolt fixing portion has a strength sufficient to withstand at least the axial force due to the bolt fastening ( Thickness) is necessary, and this causes a weight increase.

  An object of the present invention is to reduce the weight of a bolt fixing portion in a power supply system in which battery modules are stacked via spacers.

  In order to solve the above problems, the present invention is a power supply system in which a plurality of battery modules are stacked and fixed by bolt fastening, and is in contact with the side surface of the lower battery module and inserted in the load direction of the upper battery module. The spacer is a metal member that is bent in parallel with the load direction, and the seat surface of the bolt or the washer surface used for the bolt is disposed so as to overlap the end surface of the metal member. The end face is a short face of at least two of the bent surfaces.

  In the present invention, when bolting the upper battery module, the axial force is not received only by the bolt fixing portion of the upper battery module, but the bolt seat surface or the used washer and the bolt of the upper battery module. The spacer is configured to be received through the fixed portion. For this reason, the bolt fixing portion of the upper battery module is not required to have a strength that can withstand the axial force of the bolt, and can be reduced in weight.

  In the present invention, the metal member preferably has a rectangular corrugated plate shape or a triangular wave shape. Moreover, it is more preferable to have a protrusion on the contact surface with the side surface of the lower battery module of the metal member. Further, a guide for supporting the spacer may be arranged in advance on the side surface of the spacer arrangement portion of the battery module. These functions and effects will be described in detail in an embodiment described later.

  According to the present invention, when bolting the upper battery module, the axial force is not received only by the bolt fixing portion of the upper battery module, but the seat surface of the bolt or the used washer and the upper battery module. Since the spacer is received through the bolt fixing portion, the bolt fixing portion of the upper battery module is not required to have a strength capable of withstanding the axial force of the bolt, and the effect that the weight can be reduced can be obtained.

(Constitution)
Embodiments of a power supply system to which the present invention can be applied will be described below with reference to the drawings.

  As shown in FIG. 1, the power supply system 10 of the present embodiment is one in which the battery modules 1 are stacked in two upper and lower stages and fixed by fastening with bolts 4. For example, the power supply system 10 is used as a power supply for a hybrid vehicle (HEV). However, the present invention is not limited to this application.

  As shown in FIG. 2, the battery module 1 includes an upper case having a flange on the side surface and a lower lid having a flange on the side surface, and has a substantially rectangular parallelepiped outer case made of metal. In other words, the outer case has a flat top, right side, left side, and bottom lid front, back, and bottom, and the top lid flange is placed on the bottom lid flange and these flanges are screwed together. Thus, a sealed casing having the flange portion 3 is configured. The flange of the lower lid has a bent portion bent upward on the end side.

  On the side surface of the battery module 1, a guide 2 of a crank-shaped plate piece that supports a spacer 6 described later is disposed (welded) in advance (see also FIG. 1).

  A positive electrode and a negative electrode output terminal are arranged on the front surface (left side in FIG. 2) of the battery module 1 (lower lid). On the back side of the upper lid (on the right side in FIG. 2), two recesses 5 are formed for positioning with the battery module 1 arranged at the upper level. In addition, two conical projections (not shown) that fit into the recess 5 are formed on the lower lid, corresponding to the position where the recess 5 of the upper lid is formed. For this reason, positioning at the time of the assembly of the power supply system 10 can be easily performed, and when the battery modules 1 are stacked, the lead-out position of the output terminal can be adjusted to the same side.

  A plurality (12 in this example) of assembled batteries are accommodated and fixed in the exterior case. Each assembled battery is configured by connecting a plurality of (four in this example) unit cells in series. Therefore, the battery module 1 of this embodiment has 48 unit cells. As such a unit cell, for example, a lithium ion secondary battery having lithium manganate or the like as a main material can be used.

  In addition, there are many wirings for detecting voltage and temperature in the outer case, but by setting the outer case to the same potential as the vehicle chassis, for example, these can be electrically connected from the outside. Protected from noise. The cells are protected by an outer case, and the safety of the power supply system is maintained even if a traffic accident occurs.

  As shown in FIG. 1, the power supply system 10 of the present embodiment has six spacers 6 that are in contact with the side surface of the lower battery module 1 and inserted in the load direction of the upper battery module 1. In order to support the load of the upper battery module 1, such a spacer needs to have a reasonable structural strength in consideration of in-vehicle use.

  3A and 3B are perspective views of the spacer 6 used in the power supply system 10 of the present embodiment. As the spacer 6, for example, a shape having two protrusions (rectangular wave shape) (FIG. 3A) or a triangular wave shape (FIG. 3B) can be used. Although FIG. 1 and FIG. 5 to be described later show that the rectangular wave spacer is used, it is needless to say that a triangular wave spacer can be used instead.

  The spacer 6 includes a protrusion (not shown) having a semicircular arc shape in the longitudinal direction (at a position where it abuts on the side surface of the lower battery module 1). In the spacer 6, the projection comes into contact with the contact surface with the side surface of the first-stage battery module 1. If the projection is a truncated cone, the accuracy of the parallelism between the flat portions, the projection height Accuracy when assembling the power supply system such as accuracy is required. However, in this embodiment, by making the shape of the protrusion a semicircular arc shape, the same degree of accuracy is required for the height of the protrusion, but the parallelism is not required and point contact can be achieved. Further, this protrusion also has a meaning of avoiding the bending margin (R portion) of the bent portion on the receiving side of the lower battery module 1, and this allows the end portion of the spacer 6 to ride on the bending margin of the bent portion. It can receive the lashing force for fixing on a firm surface.

  The spacer 6 is supported by the guide 2 and fixed by the bolt 4. Here, what is important for preventing the looseness of the bolt 4 and the deformation of the flange portion 3 of the second-stage battery module 1 to which the bolt 4 is fixed is that the seating surface of the bolt 4 passes through the flange portion 3. The metal member is disposed so as to overlap the end face of the spacer 6 which is bent, and the end faces are at least two end faces of the bent face (see FIG. 4). The battery module 1 is previously formed so as to form a slit that is substantially parallel to the side surface of the battery module 1 so that the spacer 6 can be inserted in the load direction of the battery module 1 of the second stage as a pair. It is attached to the side of the. The spacer 2 defines the maximum separation distance from the battery module 1 by the guide 2, and the minimum separation distance from the battery module 1 is defined by the protrusion described above.

(Assembly procedure)
Next, the assembly procedure of the power supply system 10 of this embodiment is demonstrated.

  As shown in FIG. 5, the battery module 1 is placed on the floor base (attachment portion) corresponding to the bottom shape of the lower lid (see also the broken line portion in FIG. 1). The mounting portion may be disposed on the vehicle side, or may be disposed in a case that further accommodates the upper and lower two-stage battery modules 1 shown in FIG. Since the battery module 1 has the flange part 3 at this time, positioning at the time of mounting can be performed easily. Moreover, the flange part 3 is formed with a hole for attachment to the attachment part, and is fastened with a bolt after the battery module 1 is arranged using this. Thereby, the first-stage battery module 1 is fixed.

  Thereafter, the spacer 6 is inserted (inserted) between the guides 2 arranged in advance on the upper lid, and the second-stage battery module 1 is arranged. At this time, the spacer 6 contacts the back surface of the flange portion 3 of the second-stage battery module 1. The positioning when the battery module 1 is arranged in two upper and lower stages is determined by the above-described recess 5 (first battery module 1) of the upper lid and the projection (second battery module 1) (not shown) of the lower lid. I'm in charge. That is, the second-stage battery module 1 is arranged so that the protrusion on the lower lid of the second-stage battery module 1 fits into the recess 5 on the upper lid of the first-stage battery module 1.

  Next, the long bolt 4 is inserted into the round hole in which the spacer 6 is mounted through the hole formed in the flange portion 3 of the battery module 1 on the second stage surface, and the battery module 1 on the second stage is fixed. The In this embodiment, M8 bolts were used for the bolts 4 and were fastened at 12.5 N · m. In the power supply system 10 of the present embodiment, the first-stage battery module 1 is fixed directly to the mounting portion with four bolts, and the second-stage battery module 1 is connected to the six bolts via the spacer 6. 4 is fixed.

  Table 1 below examines the positions of the spacers 6, the bolt 4 seating surfaces and the spacers 6 used in the present embodiment, and the thickness of the plate material of the bolt fixing portion of the second (upper) battery module 1. is there. Table 1 also shows comparative examples for comparison. In Table 1, (A) is the rectangular wave spacer shown in FIG. 3 (A), (B) is the triangular wave spacer shown in FIG. 3 (B), and (1) to (7) are drawings. 4 represents the positional relationship between the bolt 4 seating surface and the spacer 6 shown in (1) to (7).

  A swept vibration endurance test was conducted using the power supply system thus manufactured. The test conditions were acceleration: 5G, frequency: 20 Hz to 200 Hz, test time: X axis 5 hours, Y axis 5 hours, Z axis 10 hours. Table 1 also shows the test results. In Table 1, the looseness of the bolt 4 and the deformation of the bolt fixing portion of the second-stage (upper) battery module are indicated by “X” if present and “◯” if not present.

  As shown in Table 1, the power supply system of the example was good as a vibration test result because the M8 bolt did not loosen even when the plate material of the bolt fixing portion of the second-stage battery module 1 was thin. On the other hand, the power supply system of the comparative example showed good vibration test results only when the plate material was thick, and the M8 bolt loosened in the vibration test by thinning the plate material. In addition, after the test, when the deformation of the bolt fixing portion of the second-stage battery module was confirmed, the deformation was not confirmed in the example, whereas the thin plate material in the comparative example was temporarily deformed. confirmed. It is easily guessed that this deformation is the cause of the loosening of the bolt, and it can be seen that the power supply system of the embodiment is excellent in that the plate material can be reduced in weight. For this reason, in this embodiment, the spacer shown in the example of Table 1, the positional relationship between the bolt 4 seating surface and the spacer, and the plate thickness of the flange portion 3 of the battery module 1 were used.

(Effects etc.)
Next, effects and the like of the power supply system 10 of the present embodiment will be described.

  In the power supply system 10 of the present embodiment, when the spacers 6 are stacked with the spacers 6 interposed between the battery modules 1, the spacers 6 are in contact with the side surfaces of the lower battery modules 1 and arranged in the load direction. The battery module 1 is fixed to a mounting portion (floor base) via a spacer 6. For this reason, the installation space of the spacer 6 can be made small without using a stand (in this embodiment, since the battery module 1 has the flange part 3, it can arrange | position in the space of the battery module 1. it can.). In addition, since the spacer 6 is formed by bending a metal member in parallel to the load direction of the battery module 1 in the second stage, the contact area necessary for fixing the battery module is ensured, and the structural strength (in particular, the twist direction) is secured. , The structural strength in the bending direction) can be increased. Further, when the second-stage battery module 1 is bolted, the axial force is not received only by the bolt fixing portion of the second-stage battery module 1 but the seat surface of the bolt 4 and the second-stage battery module 1. Since the spacer 6 is received through the bolt fixing portion, the bolt fixing portion of the battery module 1 in the second stage does not need to be strong enough to withstand the axial force of the bolt and can be reduced in weight.

  In addition, since the spacer 6 has a rectangular corrugated plate shape or a triangular wave shape, when the screw fastening with the bolt 4 is employed for fixing the battery module 1 in the second stage, it is easy to make a structure that avoids a screw through hole. Further, when the rectangular corrugated spacer is used, the portion that contacts the side surface of the first-stage battery module 1 is flat, so that the first-stage battery module 1 is easily contacted and disposed. It becomes easy to perform positioning.

  Furthermore, the spacer 6 has a protrusion on the contact surface with the side surface of the lower battery module 1. In this embodiment, since the shape of the protrusion is a semicircular arc shape, accuracy is required for the protrusion height, but the accuracy of the parallelism is not required, so the unit cost of the parts is reduced, and the lower part due to the protrusion By making the contact with the battery module 1 a point contact, the contacted object (flange 3) is hardly damaged.

  Moreover, since the guide 2 for supporting the spacer 6 is previously arranged on the side surface of the battery module 1, the work when inserting the spacer 6 becomes easy. In the present embodiment, since the crank-shaped plate piece having the minimum necessary shape is used for the spacer 6, the increase in weight can be suppressed, and the occupied space generated by the guide 2 can also be suppressed. Furthermore, in this embodiment, since the guides 2 are arranged in all the battery modules 1, there is no need to make a separate arrangement by the first stage and the second stage, and the workability at the time of assembling the power supply system 10 is improved. be able to.

  In the present embodiment, an example in which the power supply system 10 is stacked and fixed with two battery modules 1 is shown. However, the present invention is not limited to this, and three or more battery modules 1 are stacked and fixed. Also good. In addition, such a power supply system may further include a case for accommodating two battery modules 1, and a controller for monitoring the voltage and temperature of each single cell constituting the power supply system is included in the case. It may be built in.

  In the present embodiment, the example in which the seat surface of the bolt 6 is brought into direct contact with the flange portion 3 of the battery module 1 at the second stage is shown, but it may be made to contact through a washer.

  As described above, the present invention is intended to reduce the weight of the bolt fixing portion in the power supply system in which the battery modules are stacked via the spacer, and thus contributes to the manufacture and sale of the power supply system. Have potential.

1 is an external perspective view of a power supply system according to an embodiment to which the present invention is applicable. It is an external appearance perspective view of the battery module which comprises the power supply system of embodiment. It is a perspective view of the spacer used for the power supply system of an embodiment, and (A) shows a square wave spacer and (B) shows a triangular wave spacer. It is explanatory drawing which shows the positional relationship of the bolt seat surface and spacer of the power supply system of embodiment, (1) is 1st positional relationship, (2) is 2nd positional relationship, (3) is 3rd positional relationship. (4) is the fourth positional relationship, (5) is the fifth positional relationship, (6) is the sixth positional relationship, and (7) is the seventh positional relationship. It is a perspective view at the time of the assembly of the power supply system of embodiment.

Explanation of symbols

1 Battery Module 2 Guide 3 Flange 6 Spacer 10 Power System

Claims (4)

  A power supply system in which a plurality of battery modules are stacked and fixed by bolt fastening, and includes a spacer that is in contact with a side surface of a lower battery module and inserted in a load direction of the upper battery module, and the spacer has the load direction And a seat surface of the bolt or a washer surface used therefor is disposed so as to overlap an end surface of the metal member, and the end surface is at least of the bent surface. A power supply system having two short sides.   The power supply system according to claim 1, wherein the metal member has a rectangular wave plate shape or a triangular wave shape.   The power supply system according to claim 1, wherein a protrusion is provided on a contact surface of the metal member with a side surface of the lower battery module.   The power supply system according to any one of claims 1 to 3, wherein a guide for supporting the spacer is disposed in advance on a side surface of the spacer arrangement portion of the battery module.

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