Vehicle

Abstract

A vehicle according to the present disclosure comprises: a travel battery in which electric energy used for vehicle travel is accumulated; a battery case in which the travel battery is stored; and a front sub-frame to which a front suspension is attached. The battery case has a lower case opened upwards, an upper case that closes the opening of the lower case, and a center frame arranged in an internal space formed by the lower case and the upper case. The center frame is fastened to the front sub-frame.

Description

Vehicle

[0001] This technology relates to the technical field of vehicles having a driving battery for storing electrical energy used for driving.

[0002] For example, in electric vehicles configured to be able to drive wheels by the power of an electric motor, such as hybrid vehicles and electric vehicles, a driving battery, which is a secondary battery for supplying power to the electric motor, is installed.

[0003] The driving battery is configured to have a plurality of battery cells and a battery case for housing the battery cells. Since the driving battery has a large volume, it may be arranged under the vehicle body floor.

[0004] The battery case of the driving battery can achieve various effects through ingenuity. For example, in Patent Document 1 below, a technology is disclosed in which the shape is devised to achieve commonization of parts and suppress an increase in manufacturing cost and assembly cost.

[0005] Japanese Unexamined Patent Application Publication No. 2021 - 003940

[0006] By the way, in a vehicle, there is a problem that vibration energy generated during driving is propagated to the floor panel and radiated into the vehicle interior.

[0007] This technology has been made in view of the above circumstances, and an object thereof is to suppress the radiation of vibration energy into the vehicle interior and improve quietness by devising the structure related to the driving battery.

[0008] The vehicle according to this technology comprises a traction battery that stores electrical energy used for driving the vehicle, a battery case that houses the traction battery, and a front subframe to which the front suspension is attached. The battery case has a lower case that opens upward, an upper case that closes the opening of the lower case, and a center frame that is disposed in the internal space formed by the lower case and the upper case, and the center frame is fastened to the front subframe. Vibration energy that cannot be absorbed by the front suspension is transmitted to the front subframe. With this configuration, vibration energy from the front subframe is transmitted to the center frame by fastening the front subframe and the battery case together.

[0009] This technology can suppress the radiation of vibration energy into the vehicle cabin, thereby improving quietness.

[0010] This is a block diagram showing the configuration of the vehicle. This is an exploded perspective view showing the section where the traction battery is housed and the parts to which the traction battery is mounted. This is an exploded perspective view of the traction battery and battery case. This is a vertical cross-sectional view of the traction battery and its surroundings as seen from the front. This is a vertical cross-sectional view of the vicinity of the front end of the traction battery and its surroundings as seen from the vehicle width direction. This is a vertical cross-sectional view of the vicinity of the rear end of the traction battery and its surroundings as seen from the vehicle width direction. This is a diagram showing an example of wiring inside the battery case. This is a diagram showing a modified center frame.

[0011] <1. Vehicle Configuration> One embodiment of the configuration of the vehicle 1 in this technology will be described with reference to Figure 1. The vehicle 1 comprises a driving battery 2, a PCU (Power Control Unit) 3, a motor 4, a connector section 5, a control device 6, a display section 7, and a communication section 8.

[0012] Note that Figure 1 shows only a portion of the components of Vehicle 1, and Vehicle 1 may be equipped with a map locator, various sensors for driving, etc., as appropriate, although these are not shown.

[0013] The traction battery 2 is a high-voltage secondary battery that stores electrical energy used to power the vehicle 1. The traction battery 2 stores electrical energy used to drive the wheels, electrical energy used to operate the vehicle 1's air conditioning system, and electrical energy used to operate other equipment. Figure 1 shows the power supply from the traction battery 2 to drive the wheels and to the display unit 7, but the power supply used to operate other parts is not shown.

[0014] The PCU 3 supplies a DC voltage to the traction battery 2 for charging the traction battery 2. The PCU 3 is equipped with a DC / DC converter and the like for driving the motor 4. The PCU 3 generates an AC current to drive the motor 4 based on the power supply voltage supplied from the traction battery 2, and controls the torque of the motor 4 by controlling the AC current.

[0015] The PCU3 may also have a function to optimize energy efficiency by utilizing regenerative energy, such as by incorporating a regenerative braking function.

[0016] Motor 4 is configured as a motor generator with a power generation function, and drives the wheels based on the supplied alternating current.

[0017] The connector section 5 has a structure that allows a charging plug from a charging facility installed in each home or station to be plugged in. The connector section 5 outputs an AC voltage supplied via the plugged charging plug to the PCU 3. The PCU 3 charges the traction battery 2 by supplying a DC voltage converted by an AC / DC converter to the traction battery 2.

[0018] The control device 6 is configured with a processor such as a CPU (Central Processing Unit) and memory, and performs overall control of the vehicle 1. The control device 6 may be provided as a single unit, or it may be composed of multiple ECUs (Electronic Control Units). Multiple ECUs may include, for example, a battery control ECU that controls the charging of the traction battery 2, a display control ECU that controls the display of display devices (including meters, etc.) provided by the vehicle 1, an airbag control ECU, an air conditioning control ECU, a communication ECU that performs various types of communication, and so on.

[0019] The control device 6 performs various functions by executing various programs stored in memory, etc.

[0020] The display unit 7 comprehensively represents, for example, the Multi-Function Display (MFD) installed in front of the driver, and other display devices for presenting information to the driver. The display unit 7 displays information based on detection signals detected by various sensors installed in the vehicle 1. Various information such as the vehicle's total mileage, outside temperature, and instantaneous energy consumption is displayed on the display unit 7 as appropriate. In addition, the display unit 7 can display map information and extracted route information.

[0021] The communication unit 8 communicates with an external information processing device under the control of the control device 6. Through communication by the communication unit 8, the vehicle 1 can communicate with external server devices, vehicle-to-vehicle communication with other vehicles, and vehicle-to-infrastructure communication with roadside devices, etc.

[0022] <2. Vehicle Structure> The structure of Vehicle 1 will be explained with reference to Figure 2. In the following explanation, the direction of travel of Vehicle 1 is forward, and the front-rear direction is indicated. The width direction of Vehicle 1 is indicated as the left-right direction. The left-right direction is shown with Vehicle 1 facing forward.

[0023] Vehicle 1 comprises a floor panel 11 positioned at the occupants' feet and to which seats and the like are fixed; a front frame body 12 fastened to the front of the floor panel 11; a front subframe 13 positioned in front of the floor panel 11; and a pair of lower arms 14 attached to the left and right ends of the front subframe 13, respectively.

[0024] The floor panel 11 is formed by arranging a plate-shaped member facing vertically between a pair of side members that are spaced apart in the left-right direction and extend in the front-rear direction. The floor panel 11 has a main surface portion 15 to which a firewall FW (also called a toe board) and seats (not shown) are attached, and cross members 16 formed above and below the main surface portion 15 and extending in the left-right direction.

[0025] The floor panel 11 functions as the floor surface of the passenger compartment and the cargo compartment. The plate-shaped members of the floor panel 11 may be formed separately for the passenger compartment floor and the cargo compartment floor.

[0026] A portion of the pair of side members in the floor panel 11 is provided as a side sill 11a.

[0027] The firewall FW has a lower panel FWa, an upper panel FWb, and a firewall cross member FWc.

[0028] The lower panel FWa of the firewall FW is mounted on the upper part of the front end of the main surface portion 15 of the floor panel 11, facing approximately in the front-to-back direction. The upper end of the lower panel FWa is located in front of the lower end.

[0029] The upper panel FWb is a plate-shaped member that extends upward from the upper end of the lower panel FWa. The lower panel FWa and the upper panel FWb may be formed integrally as a single plate-shaped member, or they may be separate plate-shaped members connected to each other.

[0030] The firewall cross member FWc is mounted on the front of the lower panel FWa. The firewall cross member FWc is formed in a shape in which both ends of the left and right extending members are bent downwards. Both ends of the firewall cross member FWc are connected to the front end of the side sill 11a.

[0031] The firewall cross member FWc may have a hollow cross-section formed by, for example, press molding, or a solid cross-section formed by die-casting aluminum.

[0032] The cross member 16 may, for example, have a hollow cross-section formed by press molding, or it may have a solid cross-section formed by aluminum die casting.

[0033] The cross member 16 may be formed integrally with the main surface portion 15, or it may be formed separately from the main surface portion 15.

[0034] In Figure 2 and subsequent figures, only the cross members 16 provided on the upper part of the main surface 15 of the floor panel 11, near the boundary between the portion forming the floor under the occupants' feet and the portion forming the floor of the cargo area, are shown among the multiple cross members 16 provided by the floor panel 11.

[0035] The front frame body 12 includes, for example, a pair of first frames 12a extending in the front-rear direction and positioned spaced apart to the left and right, and one or more second frames 12b extending in the left-right direction and connecting the first frames 12a.

[0036] A pair of first frames 12a are connected to a firewall cross member FWc. The pair of first frames 12a may be fastened to a rear frame (not shown) located at the rear of the vehicle to form a pair of main frames extending in the front-rear direction.

[0037] The front subframe 13 is formed from a highly rigid material such as casting or sheet metal, and is located below the front frame body 12. The front subframe 13 has a pair of first members 13a that extend in the front-rear direction and are spaced apart in the left-right direction, one or more second members 13b that extend in the left-right direction and connect the pair of first members 13a, and a bumper beam 13c that is located furthest forward and extends in the vehicle width direction.

[0038] In addition, in vehicle 1, the bumper beam 13c may be formed separately from the front subframe 13, and the bumper beam 13c may be attached to the front subframe 13.

[0039] The lower arm 14 is formed in a Y-shape when viewed from above, for example. The outer end of the lower arm 14 in the vehicle width direction is rotatable approximately vertically, and the central end in the vehicle width direction is attached to the front subframe 13. The axis of rotation of the lower arm 14 is an axis that extends in the front-rear direction.

[0040] Each lower arm 14 is attached to the front suspension via bushings or the like (not shown). Vertical vibrations caused by uneven road surfaces are mainly absorbed by the front suspension and are therefore less likely to be transmitted to the vehicle frame. However, vibration energy transmitted from the front suspension is transmitted to the front subframe 13 via the lower arm 14.

[0041] A motor 4 is attached to the first member 13a and the second member 13b of the front subframe 13 via bushings or the like (not shown). The motor 4 attached to the front subframe 13 may be one of two motors that are mounted separately in the front-rear direction of the vehicle 1.

[0042] The vibration energy generated in the motor 4 is transmitted to the front subframe 13 via bushings and the like.

[0043] The front frame body 12 and the front subframe 13 are made of materials and have a structure that makes them more rigid than the floor panel 11.

[0044] The vehicle 1 further includes a battery case 17 disposed below the floor panel 11 and having a traveling battery 2 disposed therein.

[0045] A disassembled perspective view of the configuration of the battery case 17 is shown in FIG. 3.

[0046] The battery case 17 includes a lower case 18, an upper case 19, and a center frame 20.

[0047] The lower case 18 is formed in a box shape that is open upward by a bottom surface portion 18a, a front surface portion 18b, a rear surface portion 18c, and a pair of side surface portions 18d, 18d.

[0048] The upper case 19 functions as a lid that closes the upper opening of the lower case 18. The upper case 19 may be formed in a plate shape facing the vertical direction, or may be formed in a box shape that is open downward by including a top plate portion and four side surface portions.

[0049] The center frame 20 extends in the front-rear direction and has a closed cross section that is hollow, and is disposed substantially at the center in the left-right direction in the internal space of the battery case 17. The center frame 20 is formed to be hollow by an upper surface portion 21, a lower surface portion 22, and a pair of side surface portions 23, 23.

[0050] A plurality of holes spaced apart in the front-rear direction are formed as wiring holes 21a in the upper surface portion 21 of the center frame 20. The shape of the wiring holes 21a can be variously considered, such as a circle, an ellipse, or a rectangle. The wiring holes 21a will be described later again.

[0051] One or a plurality of battery cells 24 included in the traveling battery 2 are disposed in the internal space formed by the lower case 18 and the upper case 19.

[0052] FIG. 4 is a vertical cross-sectional view when the floor panel 11, the battery case 17, and the front sub-frame 13 are viewed from the front-rear direction of the vehicle 1.

[0053] The floor panel 11 has downward-projecting protrusions 11b formed from both ends in the vehicle width direction, thereby forming an open recess 11c. The battery case 17 is placed in the recess 11c.

[0054] As shown in Figure 3, the lower case 18 has multiple mounting protrusions 18e formed in a plate shape that extend laterally in the left-right direction and face up and down, and these protrusions are spaced apart in the front-rear direction.

[0055] The mounting projection 18e is located at approximately the same height as the bottom surface 18a of the lower case 18, and has a through hole 18f formed therein that penetrates vertically for inserting a bolt. In addition, the downward projection 11b has a screw hole 11d that opens downward at approximately the same position as the through hole 18f in the front-rear and left-right directions.

[0056] The battery case 17 is attached to the floor panel 11 from below by inserting a bolt through an insertion hole 18f of a mounting projection 18e provided on the lower case 18, and screwing the tip of the bolt into a screw hole 11d formed in the arrangement recess 11c of the floor panel 11.

[0057] The fastening of the floor panel 11, battery case 17, and front subframe 13 will be explained with reference to Figures 4, 5, and 6.

[0058] Figures 5 and 6 are both vertical cross-sectional views of the floor panel 11, battery case 17, and front subframe 13, as seen from the left-right direction of the vehicle 1. Figure 5 shows the front portion of the battery case 17, and Figure 6 shows the rear portion of the battery case 17.

[0059] As shown in Figures 4, 5, and 6, the center frame 20 is an aluminum extruded member extending in the front-rear direction, with a closed cross-section. Note that the shape and material of the center frame 20 are merely examples; for example, it may be made of a metal such as aluminum with an open cross-section, such as a hat shape, and manufactured by a method such as aluminum die-casting.

[0060] The center frame 20 is bolted to the front subframe 13 at first fastening points 25 located near the front end of each of a pair of side sections 23 that are spaced apart in the left-right direction. The bolts fastening the center frame 20 to the front subframe 13 are of a length that reaches the bolt fastening holes formed in the floor panel 11.

[0061] Furthermore, the lower case 18 and upper case 19 of the battery case 17 have holes formed in them into which bolts for fastening the center frame 20 and the front subframe 13 are inserted.

[0062] The rigidity of the front subframe 13 is set to be closer to that of the center frame 20 than to that of the lower case 18 and upper case 19. Therefore, the vibration energy transmitted to the front subframe 13 via the lower arm 14, and the vibration energy transmitted from the motor 4 to the front subframe 13, are mostly transmitted to the center frame 20 rather than to the lower case 18 and upper case 19.

[0063] As shown in Figure 6, the center frame 20 is bolted to the cross member 16 of the floor panel 11 at a second fastening point 26 located near its rear end. The rigidity of the cross member 16 is set to be closer to that of the center frame 20 than to that of the main surface portion 15. As a result, vibration energy transmitted to the center frame 20 is mainly transmitted to the cross member 16 rather than to the main surface portion 15 of the floor panel 11.

[0064] Near the rear end of both the lower case 18 and the upper case 19, similar to the area near the front end, holes are formed into which bolts for fastening the center frame 20 and the cross member 16 are inserted.

[0065] The center frame 20 may also be fastened to the lower case 18 or the upper case 19 at a predetermined position between the first fastening point 25 and the second fastening point 26.

[0066] <3. Wiring> Figure 7 is a simplified diagram showing the lower case 18 and center frame 20 of the battery case 17, and the battery cells 24 arranged inside the battery case 17. The battery cells 24 shown in Figure 7 are a part of the multiple battery cells 24 arranged in the battery case 17.

[0067] The battery cell 24 is equipped with a connector (not shown). One end of a cable 27, which has the necessary wires and other components arranged inside, is attached to the connector of the battery cell 24.

[0068] The other end of the cable 27, which is not connected to the battery cell 24, is connected to the PCU 3, control device 6, etc., located at the front of the vehicle 1.

[0069] As shown in Figure 7, the cable 27 is inserted through the wiring hole 21a of the center frame 20 and through the inside of the center frame 20.

[0070] A cable insertion hole 18g is formed in the front portion 18b of the lower case 18 of the battery case 17, at a position opposite to the front opening of the center frame 20.

[0071] One end of the cable 27 is connected to the battery cell 24, and the other end is taken out from the wiring hole 21a, through the inside of the center frame 20, and out to the outside of the battery case 17 through the cable insertion hole 18g formed in the lower case 18.

[0072] Inside the battery case 17, the portion of the cable 27 excluding the wiring from the wiring hole 21a to the battery cell 24 is placed inside the center frame 20, making it easier to neatly arrange the wiring of the cable 27 on the outside of the center frame 20. This allows for increasing the number of battery cells 24 placed inside the battery case 17, or increasing the size of individual battery cells 24 to increase the capacity.

[0073] <4. Modification> In the example described above, the center frame 20 was a member having a closed cross-section. The shape of the center frame 20 is not limited to this.

[0074] For example, as shown in Figure 8, the vehicle 1 may be configured to have a center frame 20A having an open cross-section. The center frame 20A shown in Figure 8 has a groove 21Aa formed in the center of the upper surface portion 21A that extends front to back and penetrates into the internal space.

[0075] The center frame 20A has grooves 21Aa that extend in the front-to-back direction, allowing the cable 27 to be pulled out from the inside to the outside of the center frame 20A at any point in the front-to-back direction.

[0076] This allows the length of cable 27 to be shortened, reducing costs and improving the efficiency of communication and power transmission / reception.

[0077] In the example described above, a cable insertion hole 18g was shown in the lower case 18 of the battery case 17. However, the example is not limited to this, and a hole for inserting the cable 27 may also be formed in the front part of the upper case 19 of the battery case 17. Alternatively, a semicircular hole may be formed in both the lower case 18 and the upper case 19, such that the semicircular hole becomes a circle when the lower case 18 and the upper case 19 are combined. In this case, the cable can be removed from the cable insertion hole 18g simply by separating the lower case 18 and the upper case 19.

[0078] <5. Summary> The vehicle 1 according to this technology comprises a traction battery 2 that stores electrical energy used for the vehicle 1's operation, a battery case 17 that houses the traction battery 2, and a front subframe 13 to which the front suspension is attached. The battery case 17 has a lower case 18 that opens upward, an upper case 19 that closes the opening of the lower case 18, and a center frame 20 (20A) that is positioned in the internal space formed by the lower case 18 and the upper case 19. The center frame 20 (20A) is fastened to the front subframe 13. Vibration energy flowing in from the front suspension is transmitted to the front subframe 13. With this configuration, the vibration energy from the front subframe 13 is transmitted to the center frame 20 (20A) by fastening the front subframe 13 to the battery case 17. Consequently, vibration energy transmitted from the front subframe 13 to the center frame 20 (20A) is transmitted to the battery case 17 and battery cells 24, where it is dissipated. In other words, the amount of vibration energy transmitted to the floor panel 11 is reduced, which suppresses the radiation of noise into the cabin and improves occupant comfort. In particular, it is possible to efficiently prevent the radiation of mid-frequency sounds into the cabin, which was previously difficult to address. Furthermore, by positioning the highly rigid center frame 20 (20A) inside the battery case 17, the strength of the battery case 17 against frontal or rearward collisions can be improved, and the protection of the battery cells 24 located inside the battery case 17 can be strengthened.

[0079] In vehicle 1, the rigidity of the front subframe 13 may be closer to that of the center frame 20 (20A) than to that of the lower case 18 and upper case 19. As a result, vibration energy transmitted from the front suspension to the front subframe 13 is mainly transmitted to the center frame 20 (20A), which has similar rigidity. That is, vibration energy transmitted from the front suspension to the battery case 17, such as the upper case 19 and lower case 18, is reduced, and is less likely to be transmitted to the floor panel 11 via the battery case 17. Therefore, the radiation of noise from the floor panel 11 into the passenger compartment can be suppressed, and the comfort of the occupants can be improved.

[0080] In vehicle 1, the center frame 20 (20A) has a hollow structure, providing internal space, and a portion of the wiring (cables 27) connected to the traction battery 2 may be placed in this internal space. Since space for passing the wiring connected to the battery cells 24 is secured within the center frame 20 (20A), the space required for wiring outside the center frame 20 (20A) can be reduced. Furthermore, since the wiring can be compactly arranged inside the center frame 20 (20A), the overall wiring space can be reduced. Consequently, it becomes possible to arrange more battery cells 24 in a battery case 17 of a predetermined size, or to miniaturize a battery case 17 capable of accommodating a predetermined number of battery cells 24. In addition, since most of the wiring inside the battery case 17 is placed within the high-strength center frame 20 (20A), the risk of wiring damage or disconnection can be suppressed.

[0081] In vehicle 1, the rear end of the center frame 20 (20A) may be fastened to a cross member 16 connected to a floor panel 11 located on top of the battery case 17. For example, the rigidity of the cross member 16 is set to be closer to that of the center frame 20 (20A) than to that of the floor panel 11. As a result, vibration energy transmitted from the front suspension to the front subframe 13 and then to the center frame 20 (20A) is transmitted to the cross member 16, which has a rigidity similar to that of the center frame 20 (20A). Therefore, since vibration energy is transmitted to the rear of the occupant's seating position, it is possible to improve the occupant's ride comfort and suppress the radiation of noise into the cabin.

[0082] Vehicle 1 may be equipped with a drive motor (motor 4) driven by a drive battery 2 and fastened to the front subframe 13. As a result, vibrations generated by motor 4 are mainly transmitted from the front subframe 13 to the center frame 20 (20A). Therefore, the radiation of noise into the passenger compartment during driving can be reduced, and the comfort of the occupants can be improved.

[0083] Furthermore, the various examples mentioned above can be combined as appropriate.

[0084] 1. Vehicle 2. Driving battery 4. Motor (driving motor) 11. Floor panel 13. Front subframe 16. Cross member 17. Battery case 18. Lower case 19. Upper case 20. 20A center frame

Claims

1. A vehicle comprising: a traction battery that stores electrical energy used for driving the vehicle; a battery case that houses the traction battery; and a front subframe to which a front suspension is attached, wherein the battery case has a lower case that opens upward, an upper case that closes the opening of the lower case, and a center frame disposed in the internal space formed by the lower case and the upper case, and the center frame is fastened to the front subframe.

2. The vehicle according to claim 1, wherein the rigidity of the front subframe is closer to that of the center frame than that of the lower case and the upper case.

3. The vehicle according to claim 1, wherein the center frame has a hollow structure and has a space inside, and a portion of the wiring connected to the traction battery is arranged in the space inside the center frame.

4. The vehicle according to claim 1, wherein the rear end of the center frame is fastened to a cross member connected to a floor panel located on the upper part of the battery case.

5. The vehicle according to claim 1, further comprising a drive motor driven by the drive battery and fastened to the front subframe.

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