Configuration of power supply unit in electric vehicle

Abstract

A total of four fixed points (5fl, 5fr, 5rl, 5rr) are provided at the front and rear positions of the left and right side beams (3l, 3r) provided on the floor (2), and a driving motor (9), an inverter (10), and a drive axle (11) are installed as a drive unit (8) on a rear suspension crossbeam (4) suspended and supported from each fixed point. A junction box (21), a charger (22), and a DC-AC inverter (23) are installed on the upper side of the floor (2) as a power supply unit (20), and power is supplied to the inverter (10) in the junction box (21). On the upper surface of the floor (2), an upper front floor crossbeam (16) is provided between the fixed points at the front position, and an upper rear floor crossbeam (17) is provided between the fixed points at the rear position, and a power supply unit (20) is provided between each beam (16, 17).

Description

Technical Field

[0001] The present invention relates to an arrangement structure of a power supply unit in an electric vehicle. Background Art

[0002] Electric vehicles are equipped with various power supply units that control the input and output of power to and from the traction battery. Examples of these power supply units include a junction box that connects the traction battery to electrical loads such as the traction motor; a charger that charges the traction battery with power from an external power source, such as a charging station; a DC-AC inverter that converts DC power from the traction battery into AC power for household use; and an inverter that controls power supply and regeneration for the traction motor. These power supply units are connected to the traction battery, traction motor, and other electrical loads via power lines.

[0003] Since damage to the power supply unit or disconnection of the power supply line may cause a short circuit during a vehicle collision, the installation location of the power supply unit and the wiring path of the power supply line must be carefully considered and set.

[0004] For example, Patent Document 1 discloses a rear-wheel-drive electric vehicle that takes measures against rear-end collisions. In this electric vehicle, the left and right rear wheels are supported by a rear suspension cross member that is suspended and supported on the lower side of the floor of the vehicle body, and a driving motor with an inverter and a drive axle are mounted on the suspension cross member as a drive unit to drive the rear wheels. A junction box, a charger, and a DC-AC inverter are arranged as a power supply unit on the lower side of the floor and above the drive unit. Each power supply unit, the inverter of the driving motor, and the driving battery are connected via a power cord. Furthermore, the power supply unit and the drive unit are arranged on the inner side relative to the outline of the rear suspension cross member when viewed from above. The strong rear suspension cross member is not easily deformed during a rear-end collision, thereby preventing damage to the power supply unit and the drive unit.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-151174

[0008] Technical problem to be solved by the invention

[0009] The technology in Patent Document 1 is based on a vehicle body structure in which the drive unit and power supply unit are both mounted on the rear suspension cross member below the floor. However, vehicle body structures in which the power supply unit is relocated above the floor are also widely used. In such vehicle body structures, power cables are required to connect the junction box and the inverter for the traction motor. Therefore, the power supply unit is located directly above the drive unit, in a position that is most vulnerable to rear-end collisions. Furthermore, since the power supply unit is positioned upward from the rear suspension cross member via the floor, it is less likely to be protected by the rear suspension cross member, thus requiring effective protective measures. Summary of the Invention

[0010] The present invention is completed to solve the above-mentioned technical problems. Its purpose is to provide a configuration structure of a power supply unit in an electric vehicle in a rear-wheel drive body structure in which a power supply unit is configured on the upper side of the floor of the body, which can reliably protect the power supply unit and prevent damage during a rear collision.

[0011] Technical means for solving technical problems

[0012] In order to achieve the above-mentioned purpose, the configuration structure of the power supply unit in the electric vehicle of the present invention is provided, and the electric vehicle comprises: a rear suspension cross member, which is provided on the lower side of the floor of the vehicle body on which a pair of left and right side members extending in the front-to-rear direction are provided, and the rear suspension cross member is suspended and supported from a total of four fixing points at the front and rear positions of the pair of left and right side members, and supports the left and right rear wheels via the suspension; a drive unit, which is installed on the rear suspension cross member on the lower side of the floor and includes at least a travel motor for driving the left and right rear wheels; and a power supply unit, which is installed on the upper side of the floor. , and at least includes a junction box that relays power from a driving battery and supplies the power to the driving motor. The electric vehicle also includes an upper front floor cross member and an upper rear floor cross member. The upper front floor cross member and the upper rear floor cross member are arranged in the front-to-rear direction between two fixed points at the front position and two fixed points at the rear position of the pair of left and right side members, and are respectively formed extending in the left-to-right direction on the upper surface of the floor. The power supply unit is arranged between the upper front floor cross member and the upper rear floor cross member in the front-to-rear direction (protection range 1).

[0013] With this arrangement of the power unit in an electric vehicle, in a rear-end collision, the other vehicle deforms the rear portion of the floor and intrudes forward, potentially reaching the upper rear floor cross member. Because the upper rear floor cross member, which forms a closed cross-section with the floor, has high strength, forward deformation is minimized even when subjected to strong impact from the other vehicle. Consequently, damage to the power unit, which is located forward of the upper rear floor cross member, is prevented.

[0014] As another embodiment, preferably, the electric vehicle further includes a lower front floor cross member and a lower rear floor cross member, wherein the lower front floor cross member and the lower rear floor cross member form a closed cross section with the lower surface of the floor and extend in the left-right direction, the lower front floor cross member has an area overlapping with the upper front floor cross member in the front-to-rear direction, and the lower rear floor cross member has an area overlapping with the upper rear floor cross member in the front-to-rear direction (protection range 2).

[0015] According to the arrangement structure of the power supply unit in the electric vehicle thus constructed, the upper front floor cross member and the lower front floor cross member are integrated into a strong structure extending in the left-right direction, and the upper rear floor cross member and the lower rear floor cross member are similarly integrated into a strong structure extending in the left-right direction. This improves the strength and further suppresses deformation caused by input from other vehicles in the event of a rear collision.

[0016] In another embodiment, the left and right ends of the upper front floor cross member and the upper rear floor cross member and the left and right ends of the lower front floor cross member and the lower rear floor cross member are preferably connected to the left and right side members, respectively (protection range 3).

[0017] With the power supply unit configured in this manner in an electric vehicle, the ends of the upper and lower rear floor cross members are connected to the ends of the upper and lower front floor cross members via left and right side members, forming a robust structure on the floor that, when viewed from above, appears to be a roughly rectangular frame. Consequently, the left and right side members and the upper and lower front floor cross members suppress deformation of the upper and lower rear floor cross members. Furthermore, because the equally robust rear suspension cross member is integrated into the lower side of this robust, roughly rectangular structure at various attachment points, the rear suspension cross member also suppresses deformation of the upper and lower rear floor cross members.

[0018] In addition, as another embodiment, it is preferable to further include a unit cover that covers the power supply unit from above, wherein the front portion of the unit cover is connected to the upper front floor cross member, and the rear portion of the unit cover is connected to the upper rear floor cross member (protection range 4).

[0019] According to the arrangement structure of the power supply unit in the electric vehicle configured in this manner, the unit cover also serves to suppress deformation of the upper rear portion and the lower rear portion floor cross member.

[0020] In addition, as another embodiment, it is preferred that the power supply unit is composed of multiple devices including the junction box, and the unit cover is composed of a first unit cover arranged directly above the junction box and a second unit cover arranged directly above the device other than the junction box, and the first unit cover can be loaded and unloaded separately from the second unit cover (protection range 5).

[0021] According to the arrangement structure of the power supply unit in the electric vehicle thus configured, the first unit cover immediately above the junction box can be attached and detached separately from the second unit cover, thereby improving the maintainability.

[0022] Effects of the Invention

[0023] According to the configuration structure of the power supply unit in the electric vehicle of the present invention, in a rear-wheel drive vehicle body structure in which the power supply unit is arranged above the vehicle body floor, the power supply unit can be reliably protected and prevented from being damaged during a rear-end collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a bottom view showing the rear portion of the electric vehicle according to the embodiment.

[0025] Figure 2 It is a cross-sectional view similarly showing the rear portion of the electric vehicle as viewed from the rear.

[0026] Figure 3 It is a cross-sectional view similarly showing the rear portion of the electric vehicle as viewed from the left side.

[0027] Figure 4 It is a plan view showing the arrangement of the drive unit on the rear suspension cross member.

[0028] Figure 5 It is a plan view showing the arrangement of the power supply units on the floor.

[0029] Figure 6 This is a top view showing the positional relationship and connection status of the power supply unit and drive unit.

[0030] Figure 7 This is a plan view showing the relationship between the power supply unit, the first unit cover, and the second unit cover on the floor. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of the arrangement structure of the power supply unit in the electric vehicle according to the present invention will be described.

[0032] Figure 1 is a bottom view showing the rear portion of the electric vehicle according to the embodiment, Figure 2 is a cross-sectional view similarly showing the rear portion of the electric vehicle as viewed from the rear, Figure 31 is a cross-sectional view showing the rear portion of an electric vehicle as viewed from the left. In the following description, the front and rear, left and right, and up and down directions are expressed with the driver riding in the vehicle as the main subject.

[0033] The electric vehicle of this embodiment is a hybrid vehicle 1 equipped with a running motor 9 described later and an engine not shown as a running power source. Figure 1 、 2 As shown, a pair of side members 31 and 3r are provided on the lower surface of the floor 2 constituting the vehicle body. The side members 31 and 3r form a closed cross section with the floor 2 and are provided to extend in the front-rear direction.

[0034] like Figure 1 As shown by the double-dashed line, a rear suspension cross member 4 is arranged on the lower side of the floor 2, and the left and right sides of the rear suspension cross member 4 are suspended and supported from the side members 31 and 3r. Figure 1 In the top view shown, supports 5f1, 5fr, 5rl, and 5rr (referred to as "fixing points" in the following description, as these correspond to a total of four fixing points in the present invention) are provided at the front and rear sides of the left and right side members 31 and 3r. The front and rear left and right portions of the rear suspension cross member 4 are suspended and supported from these fixing points 5f1, 5fr, 5rl, and 5rr. Furthermore, the left and right sides of the rear suspension cross member 4 extend forward from the front fixing points 5f1 and 5fr and are fastened to the left and right side members 31 and 3r by a pair of bolts 61 and 6r, respectively.

[0035] Left and right rear wheels 7 (only the right side is shown) are supported on the left and right sides of the rear suspension cross member 4 via double wishbone suspensions (not shown). While the structure of this suspension is well known and will not be described in detail, it comprises an upper arm, a lower arm, a toe-type control link, springs, shock absorbers, and other components. To withstand input from the road and driving reaction forces on the rear wheels 7 during travel, the rear suspension cross member 4 is constructed of thick-walled steel plates for high strength. It is also supported by equally strong left and right side members 31 and 3r.

[0036] Figure 4 is a plan view showing the arrangement of the drive unit on the rear suspension cross member 4. Figure 5 is a top view showing the arrangement of the power supply unit on the floor 2, Figure 6 This is a top view showing the positional relationship and connection status of the power supply unit and drive unit.

[0037] like Figure 1 、 2As shown in Figure 4, on the lower side of the floor 2, as a drive unit 8, a travel motor 9, an inverter 10 integrally provided in the travel motor 9, and a drive axle 11 functioning as a speed reducer are mounted on the rear suspension cross member 4 via a support member 15. In this embodiment, in the configuration in which the travel motor 9 is sandwiched, the drive axle 11 is on the left and the inverter 10 is on the right, and they are arranged side by side in the left-right direction. The drive axle 11 is coaxially connected to the travel motor 9 and has a shape that bulges forward compared to the travel motor 9. The inner ends of the drive shafts 12 are connected to the left and right sides of the bulge, and the left and right rear wheels 7 are connected to the outer ends of each drive shaft 12.

[0038] The inverter 10 is integrally mounted to the right side of the traction motor 9, with its terminal block 10a protruding rearward of the traction motor 9. A motor-side power cable 42, described later, is connected to the left side of the terminal block 10a. As described above, the entire area of ​​the drive unit 8 mounted on the rear suspension cross member 4 is positioned inward of the outline of the rear suspension cross member 4 when viewed from above. Furthermore, a fuel tank 13 storing fuel for the engine (not shown), the traction power source, is located below the floor panel 2, forward of the rear suspension cross member 4. A traction battery 14 is located in front of the fuel tank 13.

[0039] The drive of the traction motor 9 is controlled by an inverter 10. For example, during power supply control, DC power from the traction battery 14 is converted into three-phase AC power by the inverter 10 and supplied to the traction motor 9. The rotation of the traction motor 9 is decelerated within the drive axle 11, and the left and right rear wheels 7 are driven via the drive shaft 12. Furthermore, during regenerative control, the rotation of the left and right rear wheels 7 is transmitted to the traction motor 9 via the drive shaft 12 and the drive axle 11. The three-phase AC power generated by the traction motor 9 is converted into DC power by the inverter 10 and used to charge the traction battery 14.

[0040] like Figure 3 、 5As shown, an upper front floor cross member 16 and an upper rear floor cross member 17 are provided on the upper surface of the floor 2, and a lower front floor cross member 18 and a lower rear floor cross member 19 are provided on the lower surface of the floor 2. Specifically, the upper front floor cross member 16 is provided between left and right fixing points 5f1 and 5fr at the front side, and the upper rear floor cross member 17 is provided between left and right fixing points 5rl and 5rr at the rear side on the upper surface of the floor 2. Each of the upper front floor cross member 16 and the upper rear floor cross member 17 forms a closed cross-section with the upper surface of the floor 2, extends in the left-right direction, and is connected at both ends to the left and right side members 31 and 3r. Furthermore, on the lower surface of the floor panel 2, a lower front floor cross member 18 is provided between left and right fixing points 5f1 and 5fr at the front side, and a lower rear floor cross member 19 is provided between left and right fixing points 5rl and 5rr at the rear side. The lower front floor cross member 18 and the lower rear floor cross member 19 each form a closed cross-section with the lower surface of the floor panel 2 and are provided so as to extend in the left-right direction. Both ends of the lower front floor cross member 18 and the lower rear floor cross member 19 are connected to the left and right side members 31 and 3r.

[0041] like Figure 3 As shown, each floor cross member 16-19 is composed of a main body 16a-19a, which forms a closed cross-section with the floor 2, and front and rear flanges 16b-19b and 16c-19c, respectively, that are joined to the floor 2. Furthermore, the main bodies 16a, 18a and flanges 16b, 16c, 18b, and 18c of the upper front floor cross member 16 and the lower front floor cross member 18 all overlap in the front-to-rear direction. Furthermore, regarding the positional relationship between the upper rear floor cross member 17 and the lower rear floor cross member 19, the rear flange 17c of the upper rear floor cross member 17 and the front flange 19b of the lower rear floor cross member 19 overlap in the front-to-rear direction.

[0042] By providing an overlapping region in the front-to-rear direction across the floor 2, the upper front floor cross member 16 and lower front floor cross member 18, as well as the upper rear floor cross member 17 and lower rear floor cross member 19, are integrated and arranged to extend in the left-right direction. This significantly improves strength compared to, for example, a case where they are arranged separately in the front-to-rear direction. Furthermore, by connecting the left and right cross members 31 and 3r via these floor cross members 16-19, a robust structure is formed on the floor 2, forming a roughly square frame shape when viewed from above.

[0043] like Figures 3-5As shown, a junction box 21, a charger 22 (corresponding to multiple devices in the present invention), and a DC-AC inverter 23 (corresponding to multiple devices in the present invention) are mounted on the floor panel 2 from the left side as the power supply unit 20. As is well known, the junction box 21 connects the driving battery 14 and various power loads such as the driving motor 9. The charger 22 charges the driving battery 14 with power from an external power source such as a charging station via a charging port 30. The DC-AC inverter 23 converts the DC power of the driving battery 14 into 100V AC power, enabling use of household electricity.

[0044] In simple terms, the power supply unit 20 is mounted on the floor 2 using the upper front floor cross member 16 and the upper rear floor cross member 17. Figure 3 、 5 Taking the junction box 21 as an example, when installed, one side of an L-shaped front bracket 24 is secured to the upper front floor cross member 16 via bolts 25, while the other side of the front bracket 24 is secured to the front surface of the junction box 21 via bolts 26. Similarly, one side of an L-shaped rear bracket 27 is secured to the upper rear floor cross member 17 via bolts 28, while the other side of the rear bracket 27 is secured to the rear surface of the junction box 21 via bolts 29. As a result, the front portion of the junction box 21 is supported and secured by the upper front floor cross member 16 via the front bracket 24, while the rear portion is supported and secured by the upper rear floor cross member 17 via the rear bracket 27.

[0045] The rear bracket 27 has a curved, roughly triangular, fragile portion 27a. This portion bends and deforms to absorb the impact in the event of a rear-end collision from another vehicle. While the charger 22 and DC-AC inverter 23 will not be described repeatedly, they are installed in the same manner.

[0046] Figure 7 It is a plan view showing the relationship between the power supply unit 20 on the floor 2 and the first unit cover and the second unit cover.

[0047] like Figure 3 、 7 As shown, a first unit cover 31 is positioned directly above the junction box 21, and a second unit cover 32 is positioned directly above the charger 22 and DC-AC inverter 23. The first and second unit covers 31 and 32 are positioned adjacent to each other, with the side edges of the second unit cover 32 overlapping the side edges of the first unit cover 31 between the junction box 21 and the charger 22. As a result, the two unit covers 31 and 32 collectively form a four-sided box shape open downward. Flanges 31a and 32a formed around these units overlap the upper surfaces of the upper front floor cross member 16 and the upper rear floor cross member 17, as well as the upper surfaces of the left and right side members 31 and 3r, respectively.

[0048] Although not shown, bolt holes are provided through multiple locations on flanges 31a and 32a. Some of these bolt holes are fastened to upper rear floor cross member 17 using studs 33 and nuts 34 protruding from the upper surface of upper rear floor cross member 17. The remaining bolt holes are fastened to the upper surfaces of upper front floor cross member 16 and upper rear floor cross member 17 using bolts 35. Furthermore, although not shown, charger 22 is provided with internal threads, and second unit cover 32 is fastened to these internal threads using bolts 36. The number and position of studs 33 and bolts 35 and 36 can be arbitrarily changed.

[0049] As described above, the first unit cover 31 and the second unit cover 32 are fixed to the floor 2. These unit covers 31 and 32 cover the power supply unit 20 from above and house the power supply unit 20 therein. Since the side edges of the second unit cover 32 overlap with the side edges of the first unit cover 31, only the first unit cover 31 can be attached or detached while the second unit cover 32 is secured to the upper surfaces of the upper front floor cross member 16 and the upper rear floor cross member 17.

[0050] Furthermore, stud bolts 33 are used in some fastening locations because, when installing the unit covers 31 and 32, the unit covers 31 and 32 are first positioned by inserting the stud bolts 33 through the bolt holes in the flanges 31a and 32a, making it easier to subsequently fasten the bolts 35 and 36. Furthermore, the fastening locations of the bolts 36 on the charger 22 are designed to prevent damage if a load is applied to the upper surface of the second unit cover 32 for some reason.

[0051] The first unit cover 31 and the second unit cover 32 are made by bending a steel plate and are formed with a large number of ribs 37 ( Figure 7 Furthermore, by connecting the upper front floor cross member 16 and the upper rear floor cross member 17 to each other via the first unit cover 31 and the second unit cover 32, relative positional displacement of the two floor cross members 16 and 17 in the front-rear direction is restricted.

[0052] A third-row seat 38 is located directly above the unit covers 31 and 32. The front and rear portions of the third-row seat 38 are mounted to the floor 2 via brackets (not shown). To protect passengers seated in the third-row seat 38, the first and second unit covers 31 and 32 block electromagnetic waves radiated from the power supply unit 20 and protect the power supply unit 20 from spilled juice or other objects. Furthermore, the first and second unit covers 31 and 32, with their inner surfaces covered by sound-absorbing material (not shown), block driving noise and other sounds from the floor 2.

[0053] The reason why only the first unit cover 31 and the second unit cover 32 can be attached and detached individually is based on the following requirements.

[0054] While the charger 22 and DC-AC inverter 23 require no maintenance unless a malfunction occurs, the junction box 21 requires more frequent maintenance, such as replacing the built-in fuse and inspecting the power cord connections described below. Integrating the first and second unit covers 31, 32 would not only increase the size and make it more difficult to operate, but also increase the number of bolts required for installation and removal, making installation and removal more complicated. Therefore, only the first and second unit covers 31, 32 can be installed and removed separately, improving the maintainability of the junction box 21.

[0055] like Figure 5 As shown, on the upper side of the floor 2 and in front of the power supply unit 20, the power cord 40 connecting the junction box 21 and the charging cable 22 is connected to the side surface of the junction box 21 on the vehicle exterior side and the side surface of the charger 22 on the junction box 21 side. Similarly, the power cord 41 connecting the junction box 21 and the DC-AC inverter 23 is connected to the side surface of the junction box 21 on the vehicle exterior side and the front surface of the DC-AC inverter 23. In addition, as shown in FIG. Figure 2 、 3 As shown in FIG6 , a terminal block 21a is provided on the lower surface of the junction box 21 and is embedded in the through hole 2a formed in the floor 2 and protrudes downward. One end of the motor side power line 42 is connected to the rear surface of the terminal block 21a, and the other end of the power line 42 is connected to the left side of the terminal block 10a of the inverter 10. Figure 6 It can be seen that not only the drive unit 8 but also the motor-side power supply line 42 is arranged inside the outline of the rear suspension cross member 4 in a plan view.

[0056] In addition, since the terminal box 21 is arranged on the leftmost side in the power supply unit 20, Figure 1 As shown, this terminal block 21a is also located on the left side within the vehicle width. Furthermore, corresponding to the left-right position of the terminal block 21a, the terminal block 14a of the driving battery 14 is also located on the left side within the vehicle width and is connected to one end of a battery-side power cable 43. The battery-side power cable 43 is routed so as to bypass the left side of the fuel tank 13, and the other end of the power cable 43 is connected to the terminal block 21a of the junction box 21.

[0057] Power is exchanged between the traction battery 14, the charger 22, the DC-AC inverter 23, and the inverter 10 of the traction motor 9 via a relay relay in the junction box 21. For example, DC power from the traction battery 14 is supplied to the DC-AC inverter 23 via the junction box 21, where it is converted into 100V AC power for use in household operations. AC power supplied from an external power source, such as a charging station, is converted into DC power by the charger 22 and used to charge the traction battery 14 via the junction box 21. Furthermore, during power supply control for the traction motor 9, DC power from the traction battery 14 is supplied to the inverter 10 via the junction box 21, where it is converted into three-phase AC power and supplied to the traction motor 9. During regenerative control, the three-phase AC power generated by the traction motor 9 is converted into DC power by the inverter 10 and used to charge the traction battery 14 via the junction box 21.

[0058] On the other hand, an engine (not shown) serving as a driving power source is mounted on the vehicle body in front of the driving battery 14. The engine's exhaust pipe 44 is routed rearward, bypassing the right side of the driving battery 14 and fuel tank 13, passing under the driving motor 9 and connected to a muffler and exhaust gas purification device (not shown).

[0059] Next, the configuration of the power supply unit 20 , which is a characteristic feature of the present invention, and the protective effect of the power supply unit 20 when a rear collision occurs will be described.

[0060] Depend on Figure 3 、 5 As can be seen, all power supply units 20 are disposed between the upper front floor cross member 16 and the upper rear floor cross member 17 in the front-to-rear direction. Specifically, the front surfaces of all power supply units 20 are positioned rearward of the rear edge of the upper front floor cross member 16, and the rear surfaces of all power supply units 20 are positioned forward of the front edge of the upper rear floor cross member 17. The positional relationship between the power supply units 20, the floor cross members 16, 17, and the side members 31, 3r is not limited to the above. For example, the front and rear surfaces of the power supply units 20 may overlap with the main bodies 16a, 17a forming the closed cross section of the floor cross members 16, 17.

[0061] During a rear-end collision, another vehicle can deform the rear portion of the floor 2 and intrude forward, potentially reaching the upper rear floor cross member 17. Because the upper rear floor cross member 17, which forms a closed cross-section with the floor 2, has a certain degree of strength, forward deformation, such as forward bending, can be further suppressed even when subjected to strong impact from another vehicle. This prevents damage to the power supply units 20 located forward of the upper rear floor cross member 17 and, for example, prevents disconnection of the motor-side power cables 42 connected to the terminal block 21a of the junction box 21.

[0062] Furthermore, similar to the positional relationship with respect to the upper front floor cross member 16 and the upper rear floor cross member 17, all of the power supply units 20 are arranged between the lower front floor cross member 18 and the lower rear floor cross member 19 in the front-to-rear direction. Specifically, the front surfaces of all of the power supply units 20 are located rearward of the rear edge of the lower front floor cross member 18, and the rear surfaces of all of the power supply units 20 are located forward of the front edge of the lower rear floor cross member 19.

[0063] Furthermore, all areas of the main bodies 16a, 18a and the flanges 16b, 16c, 18b, 18c of the upper front floor cross member 16 and the lower front floor cross member 18 overlap with each other in the front-to-rear direction, and the flanges 17c, 19c of the upper rear floor cross member 17 and the lower rear floor cross member 19 also overlap with each other in the front-to-rear direction, and are integrated as a strong structure extending in the left-to-right direction.

[0064] By integrating the upper rear floor cross member 17 and the lower rear floor cross member 19 to improve strength, deformation caused by input from another vehicle during a rear collision can be further suppressed, thereby further protecting the power supply unit 20 and the like.

[0065] Furthermore, the left and right ends of the upper rear floor cross member 17 and the lower rear floor cross member 19 are connected to the left and right ends of the upper front floor cross member 16 and the lower front floor cross member 18 via the left and right side members 31 and 3r, forming a strong structure on the floor 2 that is roughly square and frame-shaped when viewed from above. Therefore, when the upper rear floor cross member 17 and the lower rear floor cross member 19 deform due to the impact of another vehicle during a rear-end collision, it is necessary to also deform the left and right side members 31 and 3r, the upper front floor cross member 16, and the lower front floor cross member 18. In other words, the left and right side members 31 and 3r, the upper front floor cross member 16, and the lower front floor cross member 18 function to suppress deformation of the upper rear floor cross member 17 and the lower rear floor cross member 19, thereby further protecting the power supply unit 20 and other components.

[0066] Furthermore, the upper front floor cross member 16 and the upper rear floor cross member 17 are connected to each other via a first unit cover 31 and a second unit cover 32, both of which have sufficient strength. Therefore, these unit covers 31 and 32 also function to suppress deformation of the rear floor cross members 17 and 19, which also contributes to the protection of the power supply unit 20 and the like.

[0067] Meanwhile, the left and right ends of the upper front floor cross member 16 and the lower front floor cross member 18 are connected to the front left and right portions of the rear suspension cross member 4 via fixing points 5fl and 5fr located in front of the left and right side members 3l and 3r. Similarly, the left and right ends of the upper rear floor cross member 17 and the lower rear floor cross member 19 are connected to the rear left and right portions of the rear suspension cross member 4 via fixing points 5rl and 5rr located in the rear of the left and right side members 3l and 3r. As a result, the equally strong rear suspension cross member 4 is integrated at the bottom of the robust, roughly rectangular structure formed by the floor cross members 16-19 and the left and right side members 3l and 3r, via fixing points 5fl, 5fr, 5rl, and 5rr. Therefore, in the event of a rear-end collision, the highly strong rear suspension cross member 4 not only prevents the forward intrusion of other vehicles but also suppresses the forward displacement of the left and right ends of the upper rear floor cross member 17 and the lower rear floor cross member 19 via the respective fixing points 5fl, 5fr, 5rl, and 5rr, thereby suppressing the forward deformation of the rear floor cross members 17 and 19. This also contributes to the protection of the power supply unit 20 and the like.

[0068] In addition, if Figure 1 、 3 As shown, in this embodiment, the drive unit 8 is also disposed between the front floor cross members 16, 18 and the rear floor cross members 17, 19 in the front-rear direction, similarly to the power supply unit 20. Moreover, the drive unit 8 is positioned lower than the outline of the rear suspension cross member 4 ( Figure 1 Therefore, in the event of a rear-end collision with another vehicle, although this description will not be repeated, the floor cross members 16 to 19, the left and right side members 31 and 3r, and the rear suspension cross member 4 provide the same protective function as in the case of the power supply unit 20, thus preventing damage to the drive unit 8 including the motor-side power supply cable 42.

[0069] While the above description of the embodiment concludes, the present invention is not limited to this embodiment. For example, the above embodiment specifically describes the configuration of the power supply unit 20 in the hybrid vehicle 1. However, any modifications can be made to any electric vehicle equipped with the power supply unit 20. For example, the present invention can also be applied to an electric vehicle equipped with a motor as a driving power source.

[0070] Furthermore, in the above embodiment, the traction motor 9, inverter 10, and transaxle 11 are disposed on the rear suspension cross member 4 as the drive unit, and the junction box 21, charger 22, and DC-AC inverter 23 are disposed on the upper side of the floor 2 as the power supply unit 20. However, their types and arrangements are not limited to this. For example, the arrangement of the traction motor 9, inverter 10, and transaxle 11 may be modified, or the inverter 10 may be disposed on the upper side of the floor 2 as one of the power supply units 20.

[0071] Explanation of symbols

[0072] 1 Electric vehicles

[0073] 2 Floor

[0074] 3l, 3r side beams

[0075] 4 Rear suspension cross member

[0076] 5fl, 5fr, 5rl, 5rr fixed points

[0077] 7 rear wheels

[0078] 8 drive units

[0079] 9 Driving motor

[0080] 14 Driving battery

[0081] 16 Upper front floor cross member

[0082] 17 Upper rear floor cross member

[0083] 18 Lower front floor cross member

[0084] 19 Lower rear floor cross member

[0085] 20 Power supply unit

[0086] 21 Junction Box

[0087] 22 chargers (multiple devices)

[0088] 23 DC-AC inverters (multiple devices)

[0089] 31, 32 unit cover

Claims

1. A configuration structure of a power supply unit in an electric vehicle, characterized in that: The electric vehicle has: A rear suspension cross member is provided on the lower side of a vehicle body floor provided with a pair of left and right side members extending in the front-rear direction, the rear suspension cross member being suspended and supported from a total of four fixing points located at the front and rear sides of the pair of left and right side members, and supporting the left and right rear wheels via the suspension; a drive unit mounted on the rear suspension cross member on the lower side of the floor and including at least a travel motor for driving the left and right rear wheels; as well as a power supply unit mounted on the upper side of the floor and including at least a junction box that relays power from a driving battery and supplies the power to the driving motor, The electric vehicle further includes an upper front floor cross member and an upper rear floor cross member, each of which is provided in a front-to-rear region between two fixing points at the front and two fixing points at the rear of the pair of left and right side members and is formed extending in the left-right direction on the upper surface of the floor. The power supply unit is disposed between the upper front floor cross member and the upper rear floor cross member in the front-rear direction.

2. The arrangement structure of the power supply unit in the electric vehicle according to claim 1, characterized in that: The electric vehicle further includes a lower front floor cross member and a lower rear floor cross member, wherein the lower front floor cross member and the lower rear floor cross member form a closed cross section with the lower surface of the floor and extend in the left-right direction. The lower front floor cross member has a region overlapping with the upper front floor cross member in the front-rear direction. The lower rear floor cross member has a region overlapping with the upper rear floor cross member in a front-rear direction.

3. The arrangement structure of the power supply unit in the electric vehicle according to claim 2, characterized in that: The left and right ends of the upper front floor cross member and the upper rear floor cross member and the left and right ends of the lower front floor cross member and the lower rear floor cross member are respectively connected to the left and right side members.

4. The arrangement structure of the power supply unit in the electric vehicle according to any one of claims 1 to 3, characterized in that: A unit cover is further provided, the unit cover covering the power supply unit from above, The front portion of the unit cover is connected to the upper front floor cross member, and the rear portion of the unit cover is connected to the upper rear floor cross member.

5. The arrangement structure of the power supply unit in the electric vehicle according to claim 4, characterized in that: The power supply unit is composed of multiple devices including the junction box. The unit cover is composed of a first unit cover arranged just above the junction box and a second unit cover arranged just above equipment other than the junction box. The first unit cover is attachable and detachable independently of the second unit cover.

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