JP2018073785A - Battery pack for vehicle mounting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress damage to a battery pack due to vehicle vibration. SOLUTION: Battery stacks 20 and 22 are arranged in parallel along the longitudinal direction on the upper surface of a lower case 12, and the lower case 12 is fixed to a vehicle 6 by fixing portions 8 at both ends in the longitudinal direction. The battery pack 10 is mounted on a vehicle and has a bent portion 12a extending in the longitudinal direction between the battery stacks 20 and 22. [Selection diagram] Figure 1

Description

  The present invention relates to a battery pack for mounting on a vehicle.

  A battery pack for storing a high-voltage battery for a vehicle is disposed under the rear seat, under the luggage compartment structure, or the like due to restrictions on the space in which the vehicle can be mounted. For example, Patent Document 1 describes a structure in which a side surface of a battery tray having a bottom surface fixed to a floor panel is fixed to a rear wheel house in order to improve rigidity of a rear wheel house to which an impact from a vehicle suspension device is transmitted. It has been. In this structure, a battery tray corresponding to the battery pack is fixed to a floor panel or a rear wheel house fastened to the vehicle body of the vehicle.

JP 2013-169849 A

  By the way, when the vehicle travels, the vibration is transmitted to the battery pack fixed to the vehicle body, so that the high voltage battery housed in the battery pack may vibrate. On the other hand, in order to improve vehicle specifications in recent years, the number of cells constituting a battery stack, which is a high-voltage battery, tends to increase. When the number of cells increases, the length dimension and mass of the battery stack increase, and the resonance frequency of the battery stack alone decreases. As a result, vibration generated in the vehicle is transmitted to the battery pack, and the battery pack and the constituent members of the battery stack may be damaged due to the resonance of the battery pack.

  Therefore, it is desired to configure the battery pack so that damage is not easily caused by the vibration of the vehicle.

  A battery pack for mounting on a vehicle according to one aspect of the present invention includes a plurality of battery stacks mounted on a vehicle, and a lower case that is a lower member of the battery pack that houses the battery stack, The lower case is disposed on the upper surface of the lower case in parallel with each other along the longitudinal direction, and the lower case is fixed between the battery stack and the fixing portion for fixing to the vehicle body at both ends in the longitudinal direction. And a bent portion extending along the line.

  According to the battery pack for mounting on a vehicle having the above-described configuration, the battery stacks are dispersed and vibrated in a direction in which the battery stacks are tilted to the opposite sides across the bent portion of the lower case provided between the battery stacks. Thereby, the acceleration of the vibration which arises in each battery stack is reduced compared with the case where a bending part is not provided. Further, by providing the bent portion along the longitudinal direction of the battery stack, the deformation amount of the lower case along the longitudinal direction can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the damage to the battery pack accompanying the vibration of a vehicle can be suppressed.

It is a figure which shows the structure of the battery pack for vehicle mounting in embodiment of this invention. It is a figure which shows the cross section of the lower case in embodiment of this invention. It is a figure explaining the mode of vibration of a lower case along the longitudinal direction (left-right direction) in an embodiment of the invention. It is a figure explaining the mode of vibration of a lower case along the width direction (front-back direction) in an embodiment of the invention. It is a figure which shows the cross section of the other example of the lower case in embodiment of this invention.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. The shapes, dimensions, materials, arrangement relations, and the like described below are examples for explanation, and can be appropriately changed according to the specifications of the battery pack for mounting on the vehicle. Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a view showing a battery pack 10 for mounting on a vehicle. In FIG. 1, as the three orthogonal directions for the battery pack 10, a front-rear direction regarding the front side and the rear side, a width direction regarding the left side and the right side, and a vertical direction regarding the upper side and the lower side are shown. The front-rear direction is the same direction as the front-rear direction of the vehicle, the width direction is the same direction as the vehicle width direction of the vehicle, and the vertical direction is the same direction as the vertical direction of the vehicle.

  The battery pack 10 is one in which battery stacks 20 and 22 that are high-voltage batteries are housed in an internal space of a case body called a pack case. The pack case is a substantially rectangular parallelepiped case, and includes a lower case 12 that is a lower member and an upper case that is combined with the lower case 12 to form an internal space. FIG. 1 is a diagram showing the battery pack 10 with the upper case removed.

  FIG. 1 shows the vehicle body 6 of the vehicle and the fixing portion 8 that fixes the battery pack 10 to the vehicle body 6. The fixing portion 8 includes, for example, a fastening member that fixes the battery pack 10 to the vehicle body. The fastening member may be a combination of a bolt and a nut, for example.

  The lower case 12 includes a metal plate 14 having a substantially rectangular planar shape having an appropriate thickness, and a reinforcing portion 16 surrounding the four sides of the metal plate 14. The reinforcing portion 16 is a frame-shaped member that surrounds the periphery of the metal plate 14. For example, the reinforcing portion 16 can be configured by combining two plate members that form two sides extending in the left-right direction and two plate members that form two sides extending in the front-rear direction. The rigidity of the reinforcing portion 16 is preferably higher than the rigidity of the metal plate 14. That is, the reinforcing portion 16 is provided to increase the rigidity of the four sides around the metal plate 14. The four corners of the reinforcing portion 16 are fixed to the vehicle body 6 via the fixing portion 8.

  The lower case 12 is formed by forming a sheet metal having an appropriate strength into a predetermined shape including a portion of the metal plate 14 by press working or the like. Further, the reinforcing portion 16 is formed by pressing a sheet metal which is a member different from the metal plate 14 by press working or the like, and then fixed to the metal plate 14 by welding or the like. Instead of this, the reinforcing portion 16 may be formed by performing a process of turning back the peripheral portion of the sheet metal to be the metal plate 14 during the press working. In this case, the metal plate 14 and the reinforcing portion 16 have an integral structure.

  Each of the battery stacks 20 and 22 includes an assembled battery in which a plurality of single cells are connected in series and in parallel. The battery stacks 20 and 22 are high voltage batteries that can output a high voltage and a large current required for an electric device mounted on the vehicle. The single battery is generally called a cell, and for example, a lithium ion battery, a nickel hydride battery, or the like can be applied.

  The battery stacks 20 and 22 are arranged on the upper surface of the lower case 12 in parallel along the longitudinal direction with the direction of the longest side of the substantially rectangular parallelepiped as the longitudinal direction. The battery stacks 20 and 22 are attached to the lower case 12 using attachment members 24 at both ends in the longitudinal direction. FIG. 1 shows an example in which the battery stacks 20 and 22 are arranged on the lower case 12 with the longitudinal direction aligned with the left-right direction of the battery pack 10. In the example of FIG. 1, the battery stacks 20 and 22 have the same shape and the same size.

  In the present embodiment, a bent portion 12 a is provided between the two battery stacks 20, 22 arranged on the upper surface of the lower case 12, and the lower case 12 is bent in a step shape along the longitudinal direction of the battery stacks 20, 22. . The bent portion 12a is provided from the left end portion in the left-right direction of the lower case 12 to the right end portion. FIG. 2 is a cross-sectional view of the lower case 12 along the front-rear direction. As shown in FIG. 2, the lower case 12 has a bent portion 12a at a substantially central portion in the front-rear direction, whereby the rear side has a step in the vertical direction of the lower step portion 12b and the front side of the upper step portion 12c. .

  The bent portion 12a may be formed simultaneously when the metal plate 14 and the reinforcing portion 16 are pressed. Or after combining the metal plate 14 and the reinforcement part 16, you may bend and form the location corresponding to the bending part 12a.

  When the battery pack 10 is mounted on a vehicle, the vibration is transmitted to the battery pack 10 when the vehicle vibrates. Since the lower case 12 has high rigidity, the vibration from the vehicle body 6 is transmitted through the fixed portion 8 and vibrates as a whole.

  If the number of cells constituting the battery stacks 20 and 22 is increased according to the vehicle specifications, the longitudinal dimensions of the battery stacks 20 and 22 are long and the weight is increased. As a result, the resonance frequency of the battery stacks 20 and 22 tends to decrease, and it tends to resonate with respect to general vibration generated in the vehicle. In addition, since the battery stacks 20 and 22 are longer in the longitudinal direction than in the width direction, the lower case 12 to which the battery stacks 20 and 22 are attached has a side length along the longitudinal direction (left and right direction). It is made longer than the length of the side along the direction (front-rear direction). Therefore, in particular, the amplitude (deformation amount) of vibration of the lower case 12 along the longitudinal direction (left and right direction) of the battery stacks 20 and 22 becomes larger than the amplitude of vibration along other directions. It is likely to cause damage to the skin.

  The lower case 12 of the present embodiment is provided with a bent portion 12a, and the bent portion 12a increases the mechanical rigidity of the lower case 12 along the longitudinal direction (left and right direction) of the battery stacks 20 and 22. Thereby, the amplitude of vibration along the longitudinal direction (left-right direction) of the lower case 12 when vibration is applied to the battery pack 10 is reduced. For example, as shown in FIG. 3A, when the lower case 12 does not have the bent portion 12a, the vibration amplitude A along the longitudinal direction (left-right direction) of the battery stacks 20 and 22 is large. On the other hand, as shown in FIG. 3B, by providing the lower case 12 with the bent portion 12a, the amplitude A of vibration along the longitudinal direction (left and right direction) of the battery stacks 20 and 22 is reduced.

  As a result, the amount of bending deformation along the longitudinal direction (left-right direction) of the battery stacks 20 and 22 can also be reduced, and the occurrence of damage to the battery stacks 20 and 22 can be suppressed.

  Further, the bent portion 12a formed by pressing or bending is mechanically aligned in the front-rear direction compared to the region other than the bent portion 12a of the lower case 12 (the lower step portion 12b and the upper step portion 12c shown in FIG. 2). Bending rigidity decreases. In the battery pack 10 in which the battery stacks 20 and 22 are arranged on both sides with such a bent part 12a interposed therebetween, the vertical vibration input to the battery stacks 20 and 22 is changed according to the deformation of the lower case 12. 22 vibrations in the front-rear direction. That is, on the battery stack 20 side, deformation occurs so that the normal line of the upper surface of the lower step 12b of the lower case 12 faces the front side, and vibration occurs such that the battery stack 20 falls to the front side. In addition, the battery stack 22 is deformed so that the normal line of the upper surface of the upper step 12c of the lower case 12 faces the rear side, and the battery stack 22 is vibrated so as to fall back. In particular, since the bent portion 12a is provided, the lower case 12 is easily deformed around the bent portion 12a having a low bending rigidity along the front-rear direction as shown in FIG. Can be further dispersed into vibration components that swing in the front-rear direction.

  Thereby, the vibration given to the up-down direction can be disperse | distributed to the component of the front-back direction, and the bending deformation of the battery stacks 20 and 22 accompanying the deformation | transformation to the up-down direction of the lower case 12 can be suppressed. As a result, the occurrence of damage to the battery stacks 20 and 22 can also be suppressed.

  In addition, the shape of the bent part 12a provided in the lower case 12 is not particularly limited. For example, as shown in the cross-sectional view of FIG. 5, an inverted V-shaped bent portion 12a may be used.

  Further, in the present embodiment, the battery pack 10 including the two battery stacks 20 and 22 has been described. However, the present invention can be applied even when the battery pack 10 includes three or more battery stacks. That is, the same effect can be obtained by forming the lower case 12 including the bent portion 12a between the three battery stacks.

  6 body, 8 fixing part, 10 battery pack (for vehicle mounting), 12 lower case, 12a bent part, 12b lower part, 12c upper part, 14 metal plate, 16 reinforcing part, 20, 22 battery stack, 24 mounting member.

Claims (1)

A plurality of battery stacks mounted on the vehicle;
A lower case that is a lower member of a battery pack that houses the battery stack;
With
The battery stack is arranged on the upper surface of the lower case in parallel with each other along its longitudinal direction,
The lower case has a fixing portion for fixing to the vehicle body at both ends in the longitudinal direction, and a bent portion along the longitudinal direction between the battery stacks. Battery pack.

Images