JP2020097272A - Vehicle lower part structure - Google Patents

Abstract

To inhibit vibration caused by a battery module that is a heavy component compared to a conventional structure in a vehicle lower part structure in which a battery pack is disposed below a rear seat.SOLUTION: A battery pack 100 includes: a battery module 110; cooling fans 120A, 120B which send cooling air to the battery module 110; and a control unit 130 which performs electric power management of the battery module 110. The battery module 110 is disposed closer to a rear wheel 300 than the cooling fans 120A, 120B and the control unit 130.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle understructure, and more particularly, to a vehicle understructure in which a battery pack is arranged under a rear seat.

A battery pack is mounted as a power source in a hybrid vehicle or an electric vehicle that uses a rotating electric machine as a drive source. For example, in Patent Document 1, a battery pack is mounted under a rear seat.

The battery pack includes battery modules, a cooling fan, and auxiliary equipment such as a control unit. The battery module is configured to include a stack (multilayer body) in which a plurality of single cells, which are also called single cells, are stacked. The cooling fan takes in air from the passenger compartment (cabin) and sends it to the battery module. The control unit manages charge and discharge of the battery module.

For example, as shown in FIG. 3, in a battery pack 500 disclosed in Patent Document 1 or the like, a battery module 510, an auxiliary machine 520 such as a DC/DC converter, and a cooling fan 530 are arranged side by side in the vehicle width direction. It

JP, 2016-172537, A

By the way, in order to extend the electric traveling distance (cruising distance) of the vehicle, the capacity of the battery module is increased. As a result, many unit cells are stacked, and the battery module is a heavy component among various components of the vehicle.

When a vehicle runs on a rough road such as an uneven road, the battery module, which is a heavy component, moves up and down as the vehicle moves up and down. When the battery module moves away from the rear wheel (or front wheel) that is the ground point of the vehicle, the vertical vibration amplitude of the battery module increases correspondingly, and the vibration characteristics of the vehicle deteriorate.

Therefore, it is an object of the present invention to provide a vehicle underbody structure in which a vibration caused by a battery module, which is a heavy component, can be suppressed in a vehicle underbody structure in which a battery pack is arranged under a rear seat, as compared with the related art. ..

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle underbody structure including a battery pack arranged below a rear seat. The battery pack includes a battery module, a cooling fan that sends cooling air to the battery module, and a control unit that manages the power of the battery module. The battery module is arranged closer to the rear wheel than the cooling fan and the control unit.

According to the above configuration, in the battery pack, the heavy battery module is arranged closer to the rear wheel than the cooling fan and the control unit. Compared to a case where the battery module, the cooling fan, and the control unit are arranged in a row in the vehicle width direction, for example, the battery module is arranged closer to the rear wheels, so that the distance between the battery module and the rear wheels becomes shorter. Therefore, the vertical vibration of the battery module is suppressed accordingly.

According to the present invention, in the lower structure of a vehicle in which the battery pack is arranged under the rear seat, it is possible to suppress vibration caused by the battery module, which is a heavy component, more than before.

FIG. 3 is an exploded perspective view illustrating the lower structure of the vehicle according to the present embodiment. It is an AA sectional view of FIG. It is a figure which illustrates the conventional battery pack.

FIG. 1 illustrates a vehicle lower structure according to this embodiment. In addition, FIG. 2 illustrates an AA sectional view of FIG. 1 and 2, the vehicle front-rear direction is indicated by the axis indicated by the symbol FR, the vehicle width direction is indicated by the axis indicated by the symbol RW, and the vehicle vertical direction is indicated by the axis indicated by the symbol UP. The front-rear direction of the vehicle is the forward direction of the vehicle FR. The vehicle width axis RW has a rightward width direction as a positive direction. Further, the vehicle vertical axis UP has an upward direction as a positive direction. These three axes are orthogonal to each other.

The vehicle lower structure according to the present embodiment is mounted in, for example, a hybrid vehicle or an electric vehicle that uses a rotating electric machine as a drive source.

The vehicle lower portion structure according to the present embodiment includes a battery pack 100. The battery pack 100 is arranged below the rear seat 350 and in a battery housing space 200 formed on the passenger compartment floor.

1 and 2, the battery storage space 200 is a part of the rear floor panel 220, and is provided so as to be sandwiched between the center cloth 240 and the fastening panel 230 in the vehicle front-rear direction. The center cross 240 is a skeleton member extending in the vehicle width direction, and is provided in the vehicle front-rear direction center of the vehicle cabin (cabin).

Referring to FIG. 1, a pair of rockers 260, 260 which are skeleton members extending in the vehicle front-rear direction are provided at both ends (both ends) in the vehicle width direction of the vehicle interior. Both ends of the center cross 240 in the vehicle width direction are fixed to the pair of rockers 260, 260.

Referring to FIG. 2, the center cloth 240 includes a center cross upper 242 having a hat-shaped cross section which is an upper member, and a center cross lower 244 having a hat-shaped cross section which is a lower member. The flanges, which are the hat-shaped brim portions of the two, are overlapped and joined by welding or the like to form a closed cross-section structure. The front end of the center cross upper 242 is joined to the front floor panel 210 by welding or the like. Note that, in FIG. 2, a joint portion formed by welding or the like is indicated by an X-shaped mark.

The front end of the case 150 of the battery pack 100 is detachably fastened to the upper surface of the center cross upper 242 by bolts and nuts. Specifically, the case 150 includes a case cover 152 that is an upper member and a case tray 154 that is a lower member. The front end flange 152A of the case cover 152 and the front end flange 154A of the case tray 154 are superposed and fastened on the upper surface of the center cross upper 242.

The front end of the rear floor panel 220 is joined to the rear end of the center cloth 240. The rear floor panel 220 is a floor plate on the rear side of the vehicle, and around the rear wheel 300, a kick-up portion 222 is provided around the rear wheel 300 so as to have an upward slope toward the rear in order to secure a space for a suspension mechanism of the rear wheel 300. The space between the kick-up portion 222 and the center cloth 240 becomes the battery housing space 200.

The fastening panel 230 is provided on the kick-up portion 222 that is inclined when viewed from the side. The fastening panel 230 is disposed on the kick-up portion 222 in order to provide a horizontal fastening surface around the kick-up portion 222, for example. The front end of the fastening panel 230 is joined to the kick-up portion 222. The rear end of the fastening panel 230 is joined to the rear cross 280 which is a skeleton member extending in the vehicle width direction.

As illustrated in FIG. 2, the fastening panel 230 has a step structure including a horizontal portion 232, a vertical portion 234, a horizontal portion 236, and a vertical portion 238 from the rear side of the vehicle toward the front side. For example, the rear end flange 152B of the case cover 152 of the battery pack 100 and the rear end flange 154B of the case tray 154 are detachably fastened to the horizontal portion 236 by bolts and nuts or the like.

Referring to FIG. 1, the battery pack 100 includes a battery module 110, cooling fans 120A and 120B, and a control unit 130, which are housed in a case 150 (see FIG. 2). As will be described later, the battery module 110 is heavier than the cooling fans 120A and 120B and the control unit 130, and is arranged closer to the rear wheel 300 than the cooling fans 120A and 120B and the control unit 130.

As described above, the battery pack 100 is detachably fastened to the passenger compartment floor with bolts and nuts. Specifically, referring to FIG. 2, front end flange 152A of case cover 152 and front end flange 154A of case tray 154 are fastened to center cross upper 242. Further, the rear end flange 152B of the case cover 152 and the rear end flange 154B of the case tray 154 are fastened to the horizontal portion 236 of the fastening panel 230. Further, a substantially central portion of the case tray 154 in the vehicle front-rear direction is fastened to a battery cloth 250 which is a skeleton member extending in the vehicle width direction.

The cooling fans 120A and 120B send cooling air to the battery module 110. For example, the cooling fans 120A and 120B are provided on both sides in the vehicle width direction with the control unit 130 interposed therebetween. The cooling fans 120A and 120B are composed of, for example, sirocco fans.

Further, an intake port 122 is provided at an end portion of the cooling fans 120A and 120B in the vehicle width direction. Air in the vehicle compartment is sucked in through the suction port 122, and the air is sent to the battery module 110 as cooling air.

The control unit 130 manages the power of the battery module 110. For example, the control unit 130 may be a so-called battery ECU (electronic control unit) including a computer. The control unit 130 manages charge/discharge and temperature of the battery module 110, for example.

The battery module 110 is configured to include a stack in which a plurality of single cells, which are also called single cells, are stacked. For example, the single cell may be a lithium ion secondary battery or a nickel hydrogen secondary battery, or may be an all solid state battery.

The battery module 110 has a large capacity in which a plurality of single cells are stacked in order to secure a sufficient electric traveling distance (cruising distance) of the vehicle. As a result of the large capacity, the weight of the battery module 110 increases, and the battery module 110 becomes a heavy part among the constituent parts of the vehicle. For example, the battery module 110 is a heavy object next to the internal combustion engine (engine).

Referring to FIG. 2, as the battery module 110, which is a heavy object, is separated from the rear wheel 300, which is the ground contact point (fulcrum) of the vehicle, the amplitude during vertical vibration increases. For example, the battery module 110 is moved up and down while the vehicle is traveling on a rough road such as an uneven road. At this time, the farther the center of gravity 110A of the battery module 110 is from the center of gravity 300A of the rear wheel 300, the longer the arm length of the moment becomes, and the amplitude of vertical movement increases under the same load.

Therefore, in the present embodiment, in the battery pack 100, the cooling fans 120A and 120B and the control unit 130 are arranged relatively in front, and the battery module 110, which is a heavy load, is installed in the battery pack 100 more than the cooling fans 120A and 120B and the control unit 130. It is arranged near the rear wheel 300. For example, referring to FIG. 2, when the case 150 is divided into 4 to 6 in the vehicle front-rear direction, the cooling fans 120A and 120B and the control unit 130 are arranged in the front 40% space, and the rear 60% space. The battery module 110 is disposed in the.

With such an arrangement, for example, in the battery pack 100, the battery module 110, the cooling fans 120A and 120B, and the control unit 130 are arranged in a row in the vehicle width direction (in one row arrangement), as compared with the battery module 110. The center of gravity 110A of the rear wheel 300 can be brought closer to the center of gravity 300A of the rear wheel 300. As a result, the amplitude of vertical vibration of the battery module 110 can be suppressed as compared with the case of the above-mentioned one-row arrangement.

100 battery pack, 110 battery module, 110A center of gravity of battery module, 120A, 120B cooling fan, 122 inlet, 130 control unit, 150 case, 152 case cover, 154 case tray, 200 battery storage space, 210 front floor panel, 220 Rear floor panel, 222 kick-up section, 230 fastening panel, 240 center cross, 242 center cross upper, 244 center cross lower, 250 battery cross, 260 rocker, 280 rear cross, 300 rear wheel, 300A rear wheel center of gravity, 350 rear seat.

Claims (1)

A vehicle understructure comprising a battery pack arranged under a rear seat,
The battery pack is
A battery module,
A cooling fan for sending cooling air to the battery module,
A control unit for managing power of the battery module;
Equipped with
The battery module is arranged closer to the rear wheel than the cooling fan and the control unit,
Vehicle substructure.

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