CN114639915A

CN114639915A - Battery unit for vehicle and underbody of vehicle including battery unit

Info

Publication number: CN114639915A
Application number: CN202111085013.XA
Authority: CN
Inventors: 金相完; 金勍暭; 陈贤垂
Original assignee: Hyundai Motor Co; Kia Corp
Current assignee: Hyundai Motor Co; Kia Corp
Priority date: 2020-11-30
Filing date: 2021-09-16
Publication date: 2022-06-17
Also published as: KR20220076567A

Abstract

A battery unit for a vehicle and an underbody of a vehicle including the battery unit includes a lower case having two battery compartments respectively disposed in a lateral direction of the vehicle and a connecting portion convexly curved upward between the two battery compartments. The battery modules are respectively installed in the two battery compartments. The cooling block is disposed under each battery module and receives and discharges a coolant to cool the battery modules. The upper housing is mounted on an upper portion of the lower housing and has a coolant inlet through which coolant is supplied to the cooling block and a coolant outlet through which the coolant is discharged from the cooling block.

Description

Battery unit for vehicle and underbody of vehicle including battery unit

Technical Field

The present disclosure relates to a battery unit (battery unit) for a vehicle and an underbody of a vehicle including the battery unit, and more particularly, to a battery unit having a structure mounted on a lower portion of a central floor of a vehicle and an underbody of a vehicle mounted with the battery unit.

Background

An electric vehicle driven by an electric motor, such as a hybrid vehicle, a fuel cell vehicle, or an electric vehicle, includes a high-voltage battery unit that stores driving electric power supplied to the electric motor. The high voltage battery cell generally includes a case forming a sealed inner space for the battery and a plurality of battery cells (battery cells), and may further include a Battery Management System (BMS) configured to monitor a voltage, a current, a temperature, etc. of the battery module and the battery cells in the battery module mounted in the sealed inner space within the case and perform management control of the battery based thereon.

In addition, as one way of mounting the high-voltage battery module in the electric vehicle, the high-voltage battery unit is mounted in a trunk or a trunk of the vehicle, or mounted and fixed to a central floor lower portion of a vehicle body outside the vehicle. When the high voltage battery unit is installed in a trunk or trunk of a vehicle, it is difficult to install other components required for the vehicle, such as a spare tire, since the trunk or trunk of the vehicle becomes small, and in the case of a Sport Utility Vehicle (SUV) or a utility vehicle (MPV), it is difficult to install a third row seat or implement a lie flat seat using a luggage space.

When the high-voltage battery unit is mounted on the lower portion of the central floor of the vehicle, the trunk or trunk of the vehicle can be utilized to the maximum, but it is difficult to secure a space provided for transmitting power from a power train (an engine and a motor) mounted on the front portion of the vehicle to a propeller shaft of a rear wheel. Therefore, when the high voltage battery unit is installed at the lower portion of the center floor outside the vehicle, a separate motor needs to be installed to drive the rear wheels to achieve an All Wheel Drive (AWD) operation. Especially, since the installation space is limited, the size of the motor for driving the rear wheel cannot be increased, resulting in a disadvantage in power performance.

The contents in the background art are only for the background of aiding the understanding of the present disclosure and should not be considered to correspond to the related art known to those of ordinary skill in the art.

Disclosure of Invention

An object of the present disclosure is to provide a battery unit for a vehicle and an underbody of the vehicle including the same, which has a structure that is mounted on a central floor lower portion of an exterior of the vehicle while being capable of transmitting power from a power train provided at a front portion of the vehicle to rear wheels.

According to an exemplary embodiment of the present disclosure, a battery unit for a vehicle may include: a lower case having two battery compartments respectively disposed in a lateral direction of the vehicle and a connecting portion convexly curved upward between the two battery compartments; battery modules respectively installed in the two battery compartments; a cooling block disposed under each battery module and receiving and discharging a coolant to cool the battery modules; and an upper housing mounted on an upper portion of the lower housing and having a coolant inlet through which coolant is supplied to the cooling block and a coolant outlet through which the coolant is discharged from the cooling block.

One coolant inlet port may be formed in the region corresponding to each battery compartment, and one coolant outlet port may be formed in the region corresponding to each battery compartment. The battery unit may further include a first hose connected to a coolant inlet port formed in the upper case and a second hose connected to a coolant outlet port formed in the upper case. The lower case may further include hose fixtures to which first ends of the first and second hoses are respectively fixed, outside an area covered by the upper case.

At the hose fixture, the first hose may be connected to a coolant introduction hose and the coolant is introduced from another component in the vehicle through the coolant introduction hose, and the second hose may be connected to a coolant discharge hose and the coolant is discharged to another component in the vehicle through the coolant discharge hose. The lower case may include at least one bracket at an outer side surface thereof for fixing a hose for flowing the coolant.

The battery cell may further include at least one member fixed to a region of the lower case from the bottom surface to the outer side surface to fix the battery cell to a lower portion of the vehicle, and the hose fixed to the bracket may be disposed at a position higher than an uppermost end of the member. A battery cell management unit that monitors and manages the voltage or temperature of the battery cells included in each battery module may be disposed on one side surface of the battery module, and the battery module may be disposed such that the battery cell management unit faces the connection part.

The battery unit may further include a relay unit disposed between the battery module located in one of the battery compartments and the connection part to form or block an electrical connection between the battery unit and another system of the vehicle. The battery unit may further include a battery management unit that monitors and manages current, voltage, or temperature of the battery unit, and a fuse that blocks electrical connection between two battery modules when overcurrent occurs, and the battery management unit and the fuse may be provided on the battery module located in one of the battery compartments.

According to another exemplary embodiment of the present disclosure, an underbody of a vehicle may include: a central floor of the vehicle; and a battery cell comprising: a lower case provided at a lower portion of the center floor, having two battery compartments respectively provided in a lateral direction of the vehicle and a connection portion convexly curved upward between the two battery compartments, and forming an installation space below the connection portion between the two battery compartments; battery modules respectively installed in the two battery compartments; a cooling block disposed under each battery module and receiving and discharging a coolant to cool the battery modules; and an upper housing mounted on an upper portion of the lower housing and having a coolant inlet through which coolant is supplied to the cooling block and a coolant outlet through which the coolant is discharged from the cooling block, wherein a propeller shaft of the vehicle is disposed in the mounting space.

Drawings

Fig. 1 is an exploded perspective view showing a battery unit and its peripheral vehicle components according to an embodiment of the present disclosure.

Fig. 2 is a bottom view of the assembly shown in fig. 1 in an assembled state.

Fig. 3 is a side view of the assembly shown in fig. 1 in an assembled state.

Fig. 4 and 5 are sectional views taken along lines I-I and II-II of fig. 2, respectively.

Fig. 6 is a perspective view of a battery cell according to an embodiment of the present disclosure when viewed from above.

Fig. 7 is an exploded perspective view of a battery cell according to an embodiment of the present disclosure.

Fig. 8 is a plan view illustrating a battery cell according to an embodiment of the present disclosure in a state in which an upper case is removed.

Fig. 9 is an exploded perspective view illustrating a battery unit in a state in which a coolant hose is detached according to an embodiment of the present disclosure.

Fig. 10 is a perspective view illustrating a hose connection part of a battery unit according to an embodiment of the present disclosure in more detail.

Fig. 11 and 12 are a perspective view and a side view illustrating a side surface portion of a battery cell according to an embodiment of the present disclosure, respectively.

Fig. 13 is an exploded perspective view illustrating an arrangement structure of a battery module, a battery management unit, and a cooling block in a battery unit according to an embodiment of the present disclosure.

Fig. 14 is an exploded perspective view of a front cross member and a rear cross member provided at an underbody of a vehicle according to an embodiment of the present disclosure.

Fig. 15 is a bottom perspective view illustrating a state in which front and rear cross members provided at the underbody of the vehicle are coupled to a center floor according to an embodiment of the present disclosure.

Fig. 16 and 17 are views for explaining an example of a coupling structure of a front cross member and a seat cross member provided at a vehicle body bottom portion of a vehicle according to an embodiment of the present disclosure.

Detailed Description

It is understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles, such as passenger vehicles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid vehicles, hydrogen powered vehicles, and other alternative fuel (e.g., derived fuel from resources other than petroleum) vehicles. As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as gasoline-powered and electric-powered vehicles.

While the exemplary embodiments are described as performing exemplary processes using multiple units, it is understood that the exemplary processes may also be performed by one or more modules. In addition, it is understood that the term "controller/control unit" refers to a hardware device that includes a memory and a processor and that is specifically programmed to perform the processes described herein. The memory is configured to store modules that the processor is configured to execute to perform one or more processes described further below.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, quantities, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, and/or groups thereof. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

As used herein, the term "about" is to be understood as being within the normal tolerance of the art, e.g., within 2 standard deviations of the mean, unless otherwise indicated or apparent from the context. "about" can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. All numerical values provided herein are modified by the term "about," unless the context clearly dictates otherwise.

Hereinafter, a battery unit for a vehicle and an underbody of a vehicle including the same according to various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

First, a battery cell and a mounting structure of the battery cell according to an exemplary embodiment of the present disclosure will be described with reference to fig. 1 to 12.

Referring to fig. 1 to 12, a battery unit according to an exemplary embodiment of the present disclosure may be configured to be fixedly disposed under a center floor 210 of a vehicle, and a propeller shaft 320 constituting a driving device 300 of the vehicle transmits power to rear wheels 230 through the battery unit 100 in a front-rear direction of the vehicle.

The battery cell 100 according to an exemplary embodiment of the present disclosure may include: a battery case including an upper case 110a and a lower case 110b forming a sealed inner space; a battery module 120 fixedly mounted in the sealed inner space of the battery case; a relay unit 130 for forming or blocking an electrical connection between the battery unit 100 and other systems of the vehicle; a Battery Management System (BMS)132 that monitors and manages the voltage, current, temperature, etc. of the battery module 120 or the battery cells in the battery module 120; and a fuse 134 blocking electrical connection between the two battery modules when overcurrent occurs.

The lower case 110b of the battery unit 100 according to an exemplary embodiment of the present disclosure may be divided into two battery compartments 140 and a connection part 150, the two battery compartments 140 being respectively disposed in the lateral direction of the vehicle to accommodate the battery modules 120, the connection part 150 being convexly bent upward between the battery compartments 140 to connect the two battery compartments 140 to each other. The upper case 110a may cover the lower case 110b from the upper portion to form a sealed inner space. The upper case 110a may be formed to have a shape corresponding to the upper end shape of the lower case 110 b. The battery module 120 may include a plurality of battery cells electrically connected to each other. The voltage of the battery module 120 may be determined based on whether the internal plurality of battery cells are connected in series or in parallel with each other.

In various exemplary embodiments of the present disclosure, two battery modules 120 are respectively disposed in two battery compartments 140 spatially separated from each other by a connection part 150, and a relay unit 130, a BMS132, a fuse 134, and the like are mounted in one of the two battery compartments 140. Therefore, a high voltage power line connected to one battery module 120 mounted in one battery compartment 140 needs to extend to the other battery compartment 140. In this case, the electric wire may be disposed along the connection part 150 connecting the two battery compartments 140 to each other.

Meanwhile, the battery unit 100 may be mounted to be fixed to a lower portion of the center floor 210 of the vehicle from the outside of the vehicle, and the center floor 210 may have a center tunnel 211 that is convexly curved upward and extends in the front-rear direction of the vehicle. The battery unit 100 may be mounted such that the above-described battery compartments 140 of the battery unit 100 are located at the left and right sides of the central passage 211, respectively. In addition, the connection part 150 may be convexly bent upward, like the center channel 211 of the center floor 210, so that the battery unit 100 may be mounted at the lower portion of the center floor 210 of the vehicle in a state where the connection part 150 is inserted into the center channel 211.

In other words, the connection portion 150 is a portion protruding upward while connecting the upper portions of the battery compartments 140 located on both sides of the vehicle with respect to the central passage 211, and may be recessed along the central passage 211. In addition, an installation space 160 that is open in the front-rear direction of the vehicle may be formed between the two battery compartments 140 below the connection portion 150.

In an exemplary embodiment of the present disclosure, a propeller shaft 320 forming the driving apparatus 300 of the vehicle may be disposed in the installation space 160. In other words, in the battery unit 100 according to the exemplary embodiment of the present disclosure, since the mounting space 160 is formed under the case, even when the battery unit 100 is mounted under the center floor 210 of the vehicle, a space for providing the propeller shaft 320 that transmits power from the power train 310 located at the front of the vehicle to the rear wheels can be secured.

Meanwhile, the battery unit 100 according to an exemplary embodiment of the present disclosure may include a cooling device for cooling the battery module 120 disposed in the battery compartment 140. First, in the battery unit 100 according to the exemplary embodiment of the present disclosure, the cooling block 125 may be disposed under the battery module 120 to exchange heat by surface contact with the battery module 120, thereby cooling the battery module 120. One cooling block 125 may be disposed in each of the two battery compartments 140.

In addition, coolant may be introduced into the cooling block 125 and discharged from the cooling block 125 such that the cooling block 125 exhibits a desired level of cooling performance. Therefore, the battery unit 100 according to an exemplary embodiment of the present disclosure may include first and

second hoses

171 and 172 for introducing a coolant into the cooling block 125 and discharging the coolant from the cooling block 125. The first hose 171 is a hose to introduce coolant from the outside, and may be connected to the coolant inlet 111 formed in the upper case 110a of the battery cell 100. In addition, the second hose 172 is a hose that discharges the coolant from the cooling block 125, and may be connected to the coolant outlet 112 formed in the upper case 110a of the battery unit 100 as the first hose 171.

First ends of the inner hoses 127, which communicate with the cooling block 125, may be located in the coolant inlet port 111 and the coolant outlet port 112, respectively, and the first ends of the inner hoses 127 may communicate the coolant inlet port 111 and the coolant outlet port 112 with the first hose 171 and the second hose 172, respectively. One coolant inlet 111 and one coolant outlet 112 are formed in respective regions corresponding to each of the two battery compartments 140 located below the upper case 110a so that coolant can be introduced into and discharged from the cooling block 125 provided in each battery compartment 140.

The lower case 110b may include a hose fixing member 117 outside the area covered by the upper case 110a, and first ends of the first and

second hoses

171 and 172 are fixed to the hose fixing member 117, respectively. Preferably, the hose fixing piece 117 may be formed at one corner of the lower case 110b corresponding to a height at which the lower case 110b contacts the upper case 110 a. At the hose fixture 117, the first hose 171 may be connected to a coolant introduction hose 191 through which coolant is introduced from another component of the vehicle, and the second hose 172 may be connected to a coolant discharge hose 192 to supply the coolant to another component of the vehicle.

For example, in a coolant circulation path in a vehicle, coolant may be introduced through the coolant introduction hose 191 from a refrigerator for cooling the coolant to lower the temperature of the coolant, and the coolant introduced from the refrigerator may be provided to the first hose 171 fixedly connected to the coolant introduction hose 191 at the hose fixing 117. In addition, the coolant discharged from the cooling block 125 in the battery unit 100 through the second hose 172 may be supplied to a charger mounted on the vehicle to charge the battery module 120 in the battery unit 100 through the coolant discharge hose 192 fixedly connected to the second hose 172 at the hose fixture 117.

The battery cell 100 according to an exemplary embodiment of the present disclosure may include a bracket 115 for fixing a hose through which a coolant flows. The bracket 115 may be attached to an outer side surface of the lower case 110b and serves to fix a coolant hose located around the battery cell 100 in the clip.

The lower case 110b may further include at least one member 600, the at least one member 600 being fixed to a region from the bottom surface to the outer side surface of the lower case 110b to fix the battery cell at the lower portion of the vehicle. The fixing structure of the battery cell fixed by the member 600 will be described in more detail later. In an exemplary embodiment of the present disclosure, the bracket 115 may be positioned such that the coolant hose fixed to the bracket 115 is disposed at a position higher than the uppermost end of the member 600. This design minimizes exposure of the stationary hose to the underside of the vehicle, taking into account vehicle marketability related to vehicle appearance.

Meanwhile, a cell management unit (cell management unit)121 that monitors and manages the voltage or temperature of battery cells (not shown) included in the battery module 120 may be disposed on one side surface of the battery module 120 provided in the battery cells according to an exemplary embodiment of the present disclosure. The battery cell management unit 121 is preferably disposed to face the connection part.

In addition, the battery unit 100 according to an exemplary embodiment of the present disclosure may further include a relay unit 130 for forming or blocking an electrical connection between the battery unit 100 and another system of the vehicle. The relay unit 130 is a vehicle component including a plurality of relays, which are generally collectively referred to as a Power Relay Assembly (PRA), and forms or blocks an electrical connection between a high voltage battery storing electric power for driving a vehicle motor and a vehicle system in an electric vehicle.

When the vehicle is started according to the input of the driver, the relay unit 130 may be configured to operate to form an electrical connection between the battery unit 100 and the vehicle system. The relay unit 130 may block the electrical connection between the battery unit 100 and the vehicle system when it is necessary to shut down the vehicle system according to the input of the driver or the judgment of the controller due to an accident or the like. Preferably, the relay unit 130 may be disposed in one of the battery compartments, and may be disposed between the battery module 120 and the connection part 150.

As described above, the battery cell management unit 121 and the relay unit 130 are preferably disposed between the battery module 120 and the connection part 150. This is to protect the battery cell management unit 121 and the relay unit 130 from direct influence of external impact when the external impact occurs, and to minimize contact of the battery cell management unit 121 and the relay unit 130 with the coolant when the coolant leaks. In addition, the battery cell 100 according to an exemplary embodiment of the present disclosure may further include: a battery management unit (battery management unit)132 (also referred to as a Battery Management System (BMS)) that monitors and manages the current, voltage, or temperature of the battery cells 100; and a fuse 134 blocking electrical connection between the two battery modules when overcurrent occurs. The battery management unit 132 and the fuse 134 are preferably disposed at the upper portion of the battery module 120 disposed in one of the battery compartments 140 to minimize an increase in volume of the battery unit 100.

Next, a vehicle underbody according to an exemplary embodiment of the present disclosure will be described with reference to all the remaining drawings. Fig. 14 is an exploded perspective view of a front cross member and a rear cross member provided at an underbody of a vehicle according to an embodiment of the present disclosure, fig. 15 is a bottom perspective view illustrating a state in which the front cross member and the rear cross member provided at the underbody of the vehicle are coupled to a center floor according to the embodiment of the present disclosure, and fig. 16 and 17 are views for explaining an example of a coupling structure of the front cross member and a seat cross member provided at the underbody of the vehicle according to the embodiment of the present disclosure.

The driving apparatus 300 of the vehicle may include a power train 310 having an engine and a motor, and a propeller shaft 320 transmitting power from the power train 310. The power train 310 may be fixedly mounted on the sub-frame 220 located at the front of the vehicle, and the propeller shaft 320 may be provided to extend in the front-rear direction of the vehicle, with one end (e.g., a first end) connected to the power train 310. As described above, the transmission shaft 320 may be disposed in the installation space 160 below the connection part 150 of the battery unit 100. Although not shown, an exhaust pipe extending from the power train 310 to the rear of the vehicle may also be provided in the installation space 160.

As is known in the art, a propeller shaft 320 of a vehicle is an assembly for transmitting power from the powertrain 310 to the rear wheels 230. Since the power generated from the power train 310 is transmitted to the rear wheels 230 through the propeller shaft 320, the rear wheels 230 can be driven by the power of the power train 310 installed at the front of the vehicle. Since the battery cells 100 are mounted under the central floor 210, the front and

rear cross members

400 and 500 are fixedly mounted under the central floor 210 at the front and rear of the battery cells 100, respectively.

Both front cross member 400 and rear cross member 500 may be structures extending in the lateral direction of the vehicle, with both ends connected to side members 240 on the left and right sides of the vehicle, respectively, so as to form load paths (loads) toward side members 240. In addition, a front cross member 400 may be connected to the rear end of the front side member 250 to form a load path for transmitting load to the front side member 250, and a rear cross member 500 may be connected to the front end of the rear side member 260 to form a load path for transmitting load to the rear side member 260. Since the front and

rear cross members

400 and 500 are connected to the vehicle body structure (e.g., center floor, side members, front and rear side members), the rigidity of the vehicle body can be increased, thereby improving Ride and Handling (R & H) performance and Noise, Vibration and Harshness (NVH) performance of the vehicle.

Since the battery unit 100 located under the center floor 210 from the outside of the vehicle is mounted such that the outer periphery thereof is surrounded by the side members 240 located on the opposite sides and the front and

rear cross members

400 and 500 located on the front and rear sides, the mounting position of the battery unit 100 can be restricted by the side members 240 located on the opposite sides and the front and

rear cross members

400 and 500 located on the front and rear sides, and further, the battery unit 100 can be sufficiently protected from impacts from the front, rear, and sides of the vehicle.

The transmission shaft 320 of the driving device 300 is provided to pass through the installation space 160 below the connection part 150, and may be installed on at least one of the front cross member 400, the rear cross member 500, and the battery unit 100 to have a strong coupling force. Seat cross member 270 may be coupled to center floor 210 while being disposed in the left-right direction, and front cross member 400 may be disposed to vertically overlap with seat cross member 270 with center floor 210 interposed therebetween. Further improved durability of the vehicle body can be ensured by the vertically overlapping structure of the seat cross member 270 and the front cross member 400, thereby further enhancing the strength and rigidity of the vehicle body.

As another example, the front cross member 400 and the seat cross member 270 may be connected by

flanges

271, 401 with the center floor 210 interposed therebetween, while being disposed in front of or behind the seat cross member 270. Each of the front and

rear cross members

400 and 500 includes two side portions 410 or 510 and a connecting portion 420 or 520 connecting the two side portions 410 or 510.

The side portion 410 or 510 may be formed in an approximately straight shape having a U-shaped cross section, and the connection portion 420 or 520 may be formed in an upwardly protruding tunnel shape and have a U-shaped cross section similar to the side portion 410 or 510. The connection part 420 or 520 is installed to be inserted into the central passage 211 of the central floor 210. All outer ends of the side portions 410 and 510 may be connected to the side sill 240 of the vehicle to form a load path in a lateral direction, and inner ends of the side portions 410 and 510 may be coupled to opposite ends of the connection portions 420 and 520 to overlap each other, thereby maintaining a strong coupling force.

All of the side portions 410, 510 and the connection portions 420, 520 are formed to have a U-shaped cross section and to be opened upward, and the flanges 411, 421, 511, and 521 of the upward-opened portions may be coupled to the lower surface of the center floor 210 by surface contact. Thus, the center floor 210, the side sill 240, the side portions 410, 510, and the connecting portions 420, 520 form a sealed enclosed space 280 therebetween. The sealed enclosure 280 may further enhance the strength and rigidity of the vehicle body.

Both ends of the connection part 420 or 520 are formed with coupling surfaces 422 or 522, the propeller shaft 320 is coupled to the coupling surfaces 422 or 522, and ribs (beads) 423 or 523 coupled to the side part 410 or 510 are formed at both sides of the coupling surfaces 422 or 522. The coupling surface 422 or 522 is preferably formed in a plane to enhance the coupling force between the connection part 420 or 520 and the driving shaft 320, but is not limited thereto. The coupling surface 422 or 522 may be formed in the same shape as the mounting surface of the propeller shaft 320 such that the connection part 420 or 520 and the propeller shaft 320 may be coupled to each other by surface contact.

In addition, the convex rib 423 or 523 formed on the connection part 420 or 520 is formed to be connected to the side part 410 or 510. The rigidity of the coupling portion between the connection part 420 or 520 and the side part 410 or 510 may be further enhanced by the ribs 423 and 523. The first reinforcing brackets 430 or 530 are coupled to the inner surface of each side portion 410 or 510. The first reinforcing brackets 430 coupled to the side portions 410 of the front cross member 400 are coupled to the front ends of the longitudinal members 700, which will be described later, and the first reinforcing brackets 530 connected to the side portions 510 of the rear cross member 500 are connected to the rear ends of the longitudinal members 700, which will be described later.

Since the first reinforcing brackets 430, 530 are coupled to the portions where the front cross member 400 and the longitudinal member 700 are coupled to each other and the portions where the rear cross member 500 and the longitudinal member 700 are coupled to each other, respectively, the rigidity of the coupled portions may be further enhanced. A second reinforcing bracket 440 or 540 for enhancing rigidity of the coupling portion is coupled to each of the coupling surfaces 422 or 522 of the connection part 420 or 520 coupled with the driving shaft 320.

The lower side of the battery unit 100 mounted on the lower portion of the center floor 210 from the outside of the vehicle is supported by the plurality of cross members 600 and the plurality of longitudinal members 700, and is connected to the vehicle body structure. In other words, in the battery unit 100, a plurality of cross members 600 extending in the left-right direction and spaced apart from each other in the front-rear direction are coupled to the lower surface of the battery compartment 140, and longitudinal members 700 extending in the front-rear direction are coupled to the lower surface of the battery compartment 140, such that one longitudinal member 700 is provided for each battery compartment 140. In addition, the battery cell 100 may further include a connection part reinforcing member 800 recessed and coupled into the connection part 150 while extending in the front-rear direction along the mounting space 160.

The cross member 600 may be installed to span the longitudinal members 700. In particular, a first end of the cross member 600 is connected to the side sill 240 of the vehicle and a second end of the cross member 600 is connected to the connector reinforcement member 800 to form a load path in the lateral direction. In addition, since the cross member 600 is connected to the longitudinal members 700, a load path may also be formed in the front-rear direction.

As another example, the cross members 600 may be respectively located at the left and right sides of the longitudinal member 700 such that first ends of the cross members 600 are respectively connected to the left and right sides of the longitudinal member 700 and second ends of the cross members 600, which are not connected to the longitudinal member 700, are respectively connected to the side sill 240 and the joint reinforcing member 800. In this structure, the cross member 600 and the longitudinal member 700 do not vertically overlap each other, and thus there is an advantage in that the vertical height can be reduced as compared to when the members vertically overlap each other.

Each of the side sills 240 located on the left and right sides of the vehicle includes an upper surface 241, a lower surface 242, and a side surface 243 when viewed in longitudinal section, and the left and right ends of the center floor 210 are connected to the side surfaces 243 of the side sills 240, respectively. Accordingly, a receiving space 290 opened downward may be formed at a lower portion of the center floor 210 by a lower surface of the center floor 210 and the side surfaces 243 of the side members 240.

The battery compartment 140 of the battery unit 100 is mounted in the receiving space 290 such that the upper portion of the battery compartment 140 is received in the receiving space 290 and the lower portion of the battery compartment 140 protrudes downward beyond the side members 240. Such a mounting structure of the battery compartment 140 makes it possible not only to dispose the center floor 210 as close to the ground as possible to secure a sufficient indoor space, but also to dispose a large portion of the upper portion of the battery compartment 140 in the accommodation space 290 to sufficiently space the distance between the battery compartment 140 and the road surface.

The battery unit for a vehicle and the underbody of the vehicle including the same are advantageous in terms of marketability in that the battery unit is fixedly mounted from the outside of the vehicle to the lower portion of the center floor, thereby enabling maximum use of the trunk or trunk. In particular, the battery unit for a vehicle and the underbody of the vehicle including the battery unit are advantageous in terms of vehicle manufacturing cost, weight, and fuel efficiency because, when the battery unit is mounted under the center floor, the battery unit ensures a space for mounting a propeller shaft constituting a vehicle driving apparatus to transmit power to rear wheels, thereby achieving four-wheel drive without driving the rear wheels using a separate motor.

Further, the battery cell for a vehicle and the underbody of a vehicle including the same have advantages in that the battery cell mounted on the lower portion of the center floor is connected to vehicle body structures, such as side members, front side members, and rear side members, through cross members, longitudinal members, front cross members, rear cross members, and the like, thereby enhancing the rigidity of the vehicle body, improving the ride and steering (R & H) performance and the noise, vibration, and harshness (NVH) performance of the vehicle. In addition, the battery unit for a vehicle and the underbody of the vehicle including the battery unit have an advantage in that a water cooling system is applied, thereby improving cooling performance and noise reduction performance as compared with an air cooling system.

The effects obtained from the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned above can be clearly understood from the above description by those skilled in the art to which the present disclosure pertains.

While the disclosure has been shown and described with respect to certain embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made thereto without departing from the spirit and scope of the disclosure as defined by the appended claims.

Claims

1. A battery unit for a vehicle, comprising:

a lower case having two battery compartments respectively disposed in a lateral direction of the vehicle and a connecting portion convexly curved upward between the two battery compartments;

battery modules respectively installed in the two battery compartments;

a cooling block disposed under each of the battery modules and receiving and discharging a coolant to cool the battery modules; and

an upper case installed at an upper portion of the lower case and having a coolant inlet through which the coolant is supplied to the cooling block and a coolant outlet through which the coolant is discharged from the cooling block.

2. The battery cell of claim 1,

one coolant inlet port is formed in a region corresponding to each of the battery compartments, and one coolant outlet port is formed in a region corresponding to each of the battery compartments.

3. The battery cell of claim 1, further comprising:

a first hose connected to the coolant inlet port formed in the upper case, and

a second hose connected to the coolant outlet formed in the upper case.

4. The battery cell of claim 3,

the lower case further includes hose fixing members to which first ends of the first and second hoses are fixed, respectively, outside an area covered by the upper case.

5. The battery cell of claim 4,

at the hose fixing member, the first hose is connected to a coolant introduction hose and the coolant is introduced from another component in the vehicle through the coolant introduction hose, and the second hose is connected to a coolant discharge hose and the coolant is discharged to another component in the vehicle through the coolant discharge hose.

6. The battery cell of claim 1,

the lower case includes at least one bracket at an outer side surface thereof for fixing a hose through which the coolant flows.

7. The battery cell of claim 6, further comprising:

at least one member fixed to a region of the lower case from a bottom surface to an outer side surface to fix the battery cell to the lower vehicle portion,

wherein the hose fixed to the bracket is disposed at a position higher than an uppermost end of the member.

8. The battery cell of claim 1,

a cell management unit that monitors and manages a voltage or a temperature of a battery cell included in each of the battery modules is disposed on one side surface of the battery module, and the battery module is disposed such that the cell management unit faces the connection part.

9. The battery cell of claim 1, further comprising:

a relay unit disposed in one of the battery compartments and between the battery module and the connection part to form or block an electrical connection between the battery unit and another system of the vehicle.

10. The battery cell of claim 1, further comprising:

a battery management unit for monitoring and managing the current, voltage or temperature of said battery unit, an

A fuse blocking electrical connection between the two battery modules when overcurrent occurs,

wherein the battery management unit and the fuse are disposed at an upper portion of the battery module in one of the battery compartments.

11. An underbody of a vehicle, comprising:

a central floor of the vehicle; and

a battery cell, comprising:

a lower case provided at a lower portion of the center floor, having two battery compartments respectively provided in a lateral direction of the vehicle and a connection portion convexly curved upward between the two battery compartments, and forming an installation space below the connection portion between the two battery compartments;

battery modules respectively installed in the two battery compartments;

an upper case installed at an upper portion of the lower case and having a coolant inlet through which the coolant is supplied to the cooling block and a coolant outlet through which the coolant is discharged from the cooling block,

wherein a propeller shaft of the vehicle is disposed in the installation space.

12. The underbody of the vehicle according to claim 11,

13. The underbody of the vehicle according to claim 11,

the battery cell further includes:

a first hose connected to the coolant inlet port formed in the upper case, and

a second hose connected to the coolant outlet formed in the upper case.

14. The underbody of the vehicle according to claim 13,

15. The underbody of the vehicle according to claim 14,

16. The underbody of the vehicle according to claim 11,

17. The underbody of the vehicle of claim 16,

the battery cell further includes:

18. The underbody of the vehicle according to claim 11,

19. The underbody of the vehicle according to claim 11,

the battery cell further includes:

20. The underbody of the vehicle according to claim 11,

the battery cell further includes:

A fuse blocking electrical connection between the two battery modules when overcurrent occurs, and

the battery management unit and the fuse are disposed at an upper portion of the battery module in one of the battery compartments.