Electric vehicle body structure

Abstract

The present invention relates to an electric vehicle body structure including: a battery frame surrounding a battery area including a battery; and a front frame disposed on the battery frame at a front side portion of the vehicle, in which the front frame includes: a first sub-frame connected to the battery frame; a second subframe branched from the first subframe and inclined outward in a width direction of the vehicle; and a third subframe extending farther from the first subframe at the front of the vehicle than a branch point of the second subframe.

Description

Technical Field

[0001] The present disclosure relates to an electric vehicle body structure, and more particularly to an electric vehicle body structure having a front frame that maximally absorbs shock and is lightweight in response to a frontal collision of the vehicle. Background Art

[0002] Generally, a vehicle having a body-on-frame structure has a vehicle body structure formed by assembling a frame forming a lower portion thereof and a vehicle body including a passenger compartment.

[0003] In the case of an electric vehicle, different from a conventional vehicle body structure, a battery is generally disposed in an inner space of the frame. When an electric vehicle is provided with a battery, it is difficult to protect the battery in a collision for a typical body-on-frame vehicle body structure unless additional reinforcing members are provided.

[0004] In addition, the passenger compartment supports the driver's seat, so the driver of the vehicle body enters the passenger compartment and controls the vehicle while sitting on the driver's seat.

[0005] Therefore, in order to ensure driver safety and prevent the frame from deforming into the battery area in the case of a frontal collision of the vehicle body, the shock should be appropriately dispersed to multiple components of the frame, and the front frame located at the front of the vehicle should absorb as much energy as possible.

[0006] In addition, since the weight of the battery increases the weight of the entire vehicle, the vehicle body needs to be designed to be not heavy.

[0007] In order to ensure the reliability of parts and the vehicle in the case of a vehicle collision, a frontal impact assessment method is being used to conduct impact tests.

[0008] According to the test regulations, a full frontal impact test is conducted by hitting the vehicle into a completely fixed wall at a speed of 48 km / h or 56 km / h.

[0009] The partial frontal impact test is a test in which a part (40%) of the front of the vehicle is hit into a fixed wall at 64 km / h. The full frontal impact test is performed using two front side members, while the partial frontal impact test is performed using one front side member.

[0010] The small overlap impact test is a test in which a very small part (25%) of the front of the vehicle is hit into a fixed wall at 64 km / h. The small overlap impact test is a method of verifying the reliability of the vehicle in a collision by moving most of the front side members away and generally inserting a structure connected to the front side members to respond or move away the structure in the case of a collision and transmit the minimum shock to the passengers.

[0011] As described above, an electric vehicle body structure is required that can effectively respond to a collision in a frontal impact test and solve the problems described above.

[0012] (Patent Document 1) Korean Patent No. 10-0352279 (August 28, 2002) Summary of the Invention

[0013] Technical Problem

[0014] The present disclosure aims to solve the above problems, and one aspect of the present disclosure is to provide a lightweight electric vehicle body structure that can protect a battery frame by absorbing as much as possible the frontal collision of the vehicle.

[0015] Solution to the Problem

[0016] To achieve the above object, in the present disclosure, an electric vehicle body structure formed as follows is provided.

[0017] According to an embodiment of the present disclosure, an electric vehicle body structure includes: a battery frame formed to surround a battery area including a battery; and a front frame disposed on the battery frame at a front side portion of the vehicle, wherein the front frame includes: a first sub-frame connected to the battery frame; a second sub-frame branched from the first sub-frame and inclined outward in a width direction of the vehicle; and a third sub-frame extending from the first sub-frame at a front portion of the vehicle further than a branching point of the second sub-frame.

[0018] The second sub-frame and the third sub-frame may be located at the same position in a height direction of the vehicle.

[0019] A cross-section of the second sub-frame or the third sub-frame may include a plurality of closed cross-sections.

[0020] The second sub-frame includes: a first side member extending in a longitudinal direction of the vehicle and including a first groove formed in a width direction of the vehicle; and a second side member extending in the longitudinal direction of the vehicle and coupled to the first side member to form a closed cross-section, and including a second groove formed toward the closed cross-section in the width direction of the vehicle, wherein the first groove and the second groove may contact each other.

[0021] The first side member may be disposed outside the second side member in the width direction, may form a first flat portion parallel to the second side member, and a shortest distance of the first groove from the first flat portion in the width direction may increase toward a front portion of the vehicle.

[0022] The third sub-frame may have a polygonal cross-sectional structure that is symmetric in the height direction of the vehicle.

[0023] The third sub-frame may further include a reinforcing portion passing through the closed cross-section.

[0024] The third sub-frame may include a first auxiliary member and a second auxiliary member. The first auxiliary member is disposed at an end of the vehicle in the height direction, and the second auxiliary member is coupled to the first auxiliary member and has a contact portion that contacts at least one surface formed thereof.

[0025] The third sub-frame may include an outer member having a hollow space formed therein and integrally provided.

[0026] The third sub-frame may further include a mounting bracket coupled to the first sub-frame and a spring top plate coupled to the mounting bracket.

[0027] The strength of the first sub-frame may be greater than the strength of the second and third sub-frames, and the thickness of the first sub-frame may be thicker than the thickness of the second and third sub-frames.

[0028] Advantages of the Invention

[0029] As described above, in the present disclosure, through the structure described above, the energy absorption in a frontal collision can be maximized, passengers and the battery can be protected, and the weight of the vehicle body itself can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of an electric vehicle body structure according to an embodiment of the present disclosure.

[0031] Figure 2 is a view of a front frame according to an embodiment of the present disclosure when viewed from the height direction of the vehicle.

[0032] Figure 3 is a view of a front frame according to an embodiment of the present disclosure when viewed from the lateral direction of the vehicle.

[0033] Figure 4 is a diagram illustrating Figure 2 a cross-sectional view of a second sub-frame taken along lines A-A', B-B', and C-C' shown in

[0034] Figure 5 is a cross-sectional view of a third sub-frame according to an embodiment of the present disclosure.

[0035] Figure 6 is a cross-sectional view of a third sub-frame according to another embodiment of the present disclosure.

[0036] Figure 7 A cross-sectional view of a third sub-frame according to another embodiment of the present disclosure. Detailed embodiments

[0037] Hereinafter, the detailed embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the spirit of the present disclosure is not limited to the presented embodiments, and other backward inventions or other embodiments included in the spirit of the present disclosure can be easily proposed by those skilled in the art who understand the spirit of the present disclosure by adding, changing, or deleting other components within the scope of the same spirit, but they will also be considered to be included within the scope of the present disclosure.

[0038] Figure 1 A perspective view of an electric vehicle body structure according to an embodiment of the present disclosure.

[0039] The electric vehicle body structure according to an embodiment of the present disclosure includes a battery frame 100 and a front frame 200.

[0040] The battery frame 100 can be formed to surround a battery area in which a battery is disposed. The shape of the battery frame 100 is not limited and includes all frames surrounding the battery area. Since the battery is located inside the battery frame 100, the battery frame 100 can function to protect the battery from external impacts and protect the internal battery from external substances such as water.

[0041] The front frame 200 can be disposed on the battery frame 100 at the front side portion of the vehicle. When an external force is applied from the front of the vehicle, the front frame 200 can be configured to absorb as much impact as possible to minimize the impact force transmitted to the battery frame 100 below it.

[0042] For example, the front frame 200 can be configured to include a steel material. The front frame 200 can be formed of a steel material to maximize the ability to absorb collision energy caused by a frontal impact and reduce weight.

[0043] In addition, the electric vehicle body structure of the present disclosure may further include: a bottom frame beam 600 disposed on the battery frame 100; a bottom plate 400 covering at least one surface of the battery frame 100; a lateral member 500 coupled to the bottom plate 400 and disposed parallel to the width direction of the vehicle; and a rear frame 300 coupled to the battery frame 100 and located at the rear side portion of the vehicle.

[0044] Figure 2 Illustrated is the front frame according to an embodiment of the present disclosure when viewed from the height direction of the vehicle, and Figure 3The figure shows the front frame when viewed in the width direction of the vehicle and from the outside of the vehicle towards the inside.

[0045] The front frame 200 may include a first sub-frame 10, a second sub-frame 20, and a third sub-frame 30.

[0046] The first sub-frame 10 may be connected to the battery frame 100. The first sub-frame 10 may be coupled to the battery frame 100 through an additional member such as a coupling member, or may be integrally coupled to the battery frame 100 by direct welding or the like.

[0047] According to an embodiment of the present disclosure, the first sub-frame 10 may be formed to be bent to a certain degree. A folding phenomenon is likely to occur in the bent portion, and thus, when the folding phenomenon occurs in this portion due to an external impact, the deformation intruding into the battery frame 100 can be reduced, and energy can be absorbed while folding at this position. Therefore, since the first sub-frame 10 has a bent portion, the first sub-frame 10 can provide an effect of increasing the energy absorption capacity.

[0048] The second sub-frame 20 may branch from the first sub-frame 10 and may be inclined outward in the width direction of the vehicle.

[0049] For example, the second sub-frame 20 may be coupled to the first sub-frame 10 through a connection member 60 at the point where it branches from the first sub-frame 10. The second sub-frame 20 may branch from the first sub-frame 10 and may further include a connection member 60 to facilitate the connection of the branching portion. The second sub-frame 20 may be coupled to the connection member 60 so that the strength can be supplemented in this portion.

[0050] The second sub-frame 20 provides an effect of minimizing the deformation of the first sub-frame 10.

[0051] The third sub-frame 30 may be formed not from the branching point of the second sub-frame 20 but from the front portion of the vehicle and may extend from the first sub-frame 10.

[0052] The third sub-frame 30 may be connected to one end of the first sub-frame 10 and may be formed to continuously extend in a straight line along the direction forming one end of the first sub-frame 10.

[0053] For example, the second sub-frame 20 and the third sub-frame 30 may be respectively coupled to an end plate 70 at one end thereof, and the external force received by the second sub-frame 20 and the third sub-frame 30 may be stably dispersed and transmitted through the end plate 70.

[0054] The end plate 70 can be formed to have a bent portion in one part, and according to the angle of the external force applied to the end plate 70 by the bent portion, it can be transmitted in the same direction as the axis of the second sub-frame 20 or the third sub-frame 30, thereby contributing to maximizing the absorption in the axial direction.

[0055] In the full frontal impact test and the partial frontal impact test, when the third sub-frame 30 collapses in the axial direction of the third sub-frame 30, the absorption of the external collision can be maximized by the third sub-frame 30, and the second sub-frame 20 can provide a supplementary effect by assisting in absorbing some energy.

[0056] In the small overlap impact test, when the second sub-frame 20 collapses in the axial direction of the second sub-frame 20, the energy absorption can be maximized, and the third sub-frame 30 can supplement the energy absorption by assisting in undergoing bending deformation.

[0057] Utilizing the effects described above, even when an external impact is applied to the front surface from any direction, the energy absorption can be maximized by the second sub-frame 20 and the third sub-frame 30, and thus, the energy transmitted to the first sub-frame 10 can be minimized, thereby minimizing the deformation of the first sub-frame 10 and the battery frame 100.

[0058] When the absorption of the collision energy in the second sub-frame 20 and the third sub-frame 30 is maximized, the collision load transmitted to the first sub-frame 10 can be reduced, such that the first sub-frame 10 can be configured not to have an additional weight increase caused by a change in shape, such as an increase in thickness or a change in material, thereby providing a weight reduction effect.

[0059] According to an embodiment of the present disclosure, the second sub-frame 20 and the third sub-frame 30 can be disposed at the same position in the height direction of the vehicle.

[0060] The positions of the second sub-frame 20 and the third sub-frame 30 in the height direction of the vehicle can be the same. Therefore, the second sub-frame 20 and the third sub-frame 30 can be located at the same height as one end to which they are connected to the first sub-frame 10, and the collision energy can be transmitted to and absorbed by the second sub-frame 20 and the third sub-frame 30 without being concentrated on a specific part.

[0061] According to an embodiment of the present disclosure, the strength of the first sub-frame 10 can be greater than the strength of the second sub-frame 20 and the third sub-frame 30. Alternatively, the thickness of the first sub-frame 10 can be formed to be thicker than the thickness of the second sub-frame 20 and the third sub-frame 30.

[0062] In order to minimize the amount of deformation of the first sub-frame 10 and to enable the second sub-frame 20 and the third sub-frame 30 to absorb as much impact energy as possible when they are deformed, the strength of the first sub-frame 10 can be formed to be greater than the strength of the second sub-frame 20 and the third sub-frame 30.

[0063] In addition, in order to minimize the amount of deformation of the first sub-frame 10 and to enable the second sub-frame 20 and the third sub-frame 30 to absorb as much impact energy as possible when they are deformed, the thickness of the first sub-frame 10 can be thicker than the thickness of the second sub-frame 20 and the third sub-frame 30.

[0064] In addition, the first sub-frame 10 can be formed to be greater than the second sub-frame 20 and the third sub-frame 30 in both strength and thickness.

[0065] According to an embodiment of the present disclosure, the front frame 200 may further include a mounting bracket 50 coupled to the first sub-frame 10 and a spring upper plate 40 coupled to the mounting bracket 50.

[0066] The front frame 200 may further include a mounting bracket 50 and a spring upper seat 40 coupled to the mounting bracket 50.

[0067] The mounting bracket 50 may be formed to have an upper arm located at a higher position in the height direction of the vehicle of the first sub-frame 10 and may be coupled to the first sub-frame 10. The spring upper seat 40 may be coupled to the first sub-frame 10 through the mounting bracket 50 and may provide an effect of reducing the impact received by the vehicle body by using a spring.

[0068] Figure 4 is a cross-section of a second sub-frame according to an embodiment of the present disclosure taken along the width direction of the vehicle, which shows cross-sections for Figure 2 the points A-A', B-B' and C-C' shown in.

[0069] The second sub-frame 20 according to an embodiment of the present disclosure may have a cross-section including a plurality of closed cross-sections.

[0070] The cross-section of the second sub-frame 20 taken parallel to the width direction of the vehicle may include a plurality of closed cross-sections C1 and C2. The second sub-frame 20 may be configured to have a hollow interior such that the weight can be reduced and deformation can be caused in a certain direction, thereby preventing damage to other components due to accidental deformation.

[0071] For example, the second sub-frame 20 may include a first side member 21 and a second side member 22.

[0072] The first side member 21 and the second side member 22 can be joined at two ends in the height direction of the vehicle, and in a state where the first side member 21 and the second side member 22 are joined, a plurality of closed cross-sections can be formed inside.

[0073] The first side member 21 can extend in the longitudinal direction of the vehicle and include a first groove 21a formed in the width direction of the vehicle. The first side member 21 can have a first flange 21c formed therein, and the first flange 21c is bent in the same direction as the direction in which the first groove 21a is recessed at two ends in the height direction of the vehicle. In addition, a first flat portion 21b having a certain length in the height direction of the vehicle can be formed, and the first side member 21 can include the first groove 21a located in a part of the first flat portion 21b.

[0074] The second side member 22 can extend in the longitudinal direction of the vehicle and be joined to the first side member 21 to form a closed cross-section, and can include a second groove 22a formed toward the closed cross-section in the width direction of the vehicle. The second side member can have a second flange 22c, and the second flange 22c is bent in the same direction as the direction in which the second groove 22a is recessed at two ends in the height direction of the vehicle. The second side member 22 can include a second flat portion 22b parallel to the first flat portion 21b, and can have the second groove 22a by being recessed in the outward direction of the width of the vehicle in a part of the second flat portion 22b.

[0075] The first side member 21 and the second side member 22 can be joined at the first flange 21c and the second flange 22c, and the first groove 21a and the second groove 22a can be positioned to contact each other.

[0076] The depth of recess of each of the first groove 21a and the second groove 22a can vary in the longitudinal direction of the vehicle. However, the first groove 21a and the second groove 22a can extend in the longitudinal direction of the vehicle, and the first groove 21a and the second groove 22a can always contact each other at different points in the longitudinal direction of the vehicle.

[0077] Therefore, closed cross-sections can be formed vertically in the height direction of the vehicle based on the portions where the first groove 21a and the second groove 22a contact each other.

[0078] In addition, the first side member 21 can be disposed outside the second side member 22 in the width direction, a first flat portion parallel to the second side member 22 can be formed, and the shortest distance from the first flat portion 21b to the first groove 21a in the width direction can be formed to increase toward the front of the vehicle.

[0079] The first side member 21 may be formed to be closer to the outer side of the vehicle in the width direction of the vehicle than the second side member 22, and the first groove 21a may be formed by being recessed into the first side member 21 to the maximum extent in the front portion of the vehicle, and the amount of recess of the first groove 21a decreases toward the portion connected to the first sub-frame 10, such that the amount of recess of the first groove 21a is zero and may be flat in the portion connected to the first sub-frame 10.

[0080] The second side member 22 may be disposed inside the second side member 22 in the width direction, a second flat surface 22b parallel to the first flat surface 21b of the first side member 21 may be formed in the second side member 22, and the shortest distance in the width direction from the second flat portion 22b to the second groove 22a may be formed to increase toward the rear portion of the vehicle.

[0081] The first groove 21a and the second groove 22a may be hemmings formed by hemming.

[0082] Since the second sub-frame 20 is configured in the shape described above, the axial load is more transmitted to the inner side of the vehicle in the width direction in the front portion of the vehicle, thereby providing an effect of offsetting the external moment of the vehicle in the width direction that occurs in the third sub-frame 30. However, when it continues in the same cross-section in the longitudinal direction of the vehicle, the axial load continues to act inside the vehicle, which may cause a problem of bending deformation inside the vehicle. Therefore, when it moves relative to the rear side portion of the vehicle, as can be seen in the cross-section in the width direction of the vehicle, the first groove 21a may be formed to have a depth gradually decreasing toward the outer side in the width direction of the vehicle, thereby causing the second sub-frame 20 to collapse in the axial direction without bending deformation on the inner side.

[0083] Figures 5 to 7 The cross-section of the third sub-frame according to an embodiment of the present disclosure taken along the width direction of the vehicle is illustrated. Figures 5 to 7 The shapes according to each embodiment are illustrated.

[0084] The third sub-frame 30 according to an embodiment of the present disclosure may have a cross-section including a plurality of closed cross-sections C3 and C4.

[0085] In addition, the third sub-frame 30 may have a polygonal cross-section structure symmetric in the height direction of the vehicle.

[0086] Since the third sub-frame 30 forms the closed cross-sections C3 and C4, the weight can be reduced while maintaining a certain degree of rigidity. In addition, in the deformation, deformation in a specific direction can be caused.

[0087] The third sub-frame 30 may have a polygonal cross-sectional structure that is symmetric in the height direction of the vehicle. For example, the third sub-frame 30 may have an octagonal shape. However, the shape of the polygonal structure may vary according to the design.

[0088] The third sub-frame 30 may have a structure that is vertically symmetric based on a certain point.

[0089] Since the cross-section of the third sub-frame 30 has a polygonal structure and forms a shape that is symmetric in the height direction of the vehicle, when energy due to a frontal collision is applied to the third sub-frame 30, it causes the third sub-frame 30 to collapse in the axial direction rather than causing bending deformation, and the third sub-frame 30 is used to absorb energy.

[0090] Referring to Figure 5 , the third sub-frame 30 may include a first auxiliary member 31 and a second auxiliary member 32. The first auxiliary member 31 is provided at the ends in the height direction of the vehicle, and the second auxiliary member 32 is coupled to the first auxiliary member 31 and has a contact portion 33 formed therein that contacts at least one of its surfaces.

[0091] The first auxiliary member 31 is provided at both ends in the height direction of the vehicle, and the second auxiliary member 32 is provided to be coupled to the first auxiliary member 31. The first auxiliary member 31 and the second auxiliary member 32 may form a coupling portion in a part. For example, the first auxiliary member 31 may be fitted into the second auxiliary member 32, and the first auxiliary member 31 and the second auxiliary member 32 may be coupled by welding or the like or may be fixed by a mechanical coupling method such as bolt connection.

[0092] The second auxiliary member 32 may have a plurality of bent portions and a contact portion 33 formed on one of its surfaces, such that the second auxiliary member 32 can be symmetrically coupled with respect to the contact portion 33.

[0093] The first auxiliary member 31 and the second auxiliary member 32 may be continuous in the longitudinal direction of the vehicle to be coupled to the end plate 70 at the front end of the vehicle and connected to the first sub-frame 10 at the other end thereof.

[0094] Referring to Figure 6 , the third sub-frame 30 may further include a reinforcing portion 34 passing through the closed cross-section.

[0095] As described above, the first auxiliary member 31 and the second auxiliary member 32 may be coupled to form a closed cross-section therein, and a reinforcing portion 34 passing through the closed cross-section may also be provided.

[0096] The reinforcing portion 34 can be formed to pass through the closed cross-section in the vehicle width direction. By providing the reinforcing portion 34, the closed cross-section formed inside the first sub-frame 10 is divided, and since the size of the closed cross-section is reduced and a plurality of closed cross-sections are formed, an effect of increasing the critical load at which bending deformation starts can be provided.

[0097] For example, the reinforcing portion 34 can be integrally formed with the first auxiliary member 31.

[0098] The first auxiliary member 31 and the reinforcing portion 34 can be integrally formed such that a smaller number of connection portions to be connected to the second auxiliary member 32 can be formed, thereby providing convenience in terms of processing.

[0099] Refer to Figure 7 , the third sub-frame 30 can include an outer member 36 having a hollow space formed therein and integrally formed.

[0100] As another example, the third sub-frame 30 can include an outer member 36. The outer member 36 can be processed by extrusion molding, or can also be formed as a single member by bending a single sheet material and then connecting the single sheet material at its two ends.

[0101] Even when the single member is formed by the outer member 36, it can be arranged in a symmetric shape in the vehicle height direction, and when forming the connection portion formed by bending and then connecting the single sheet material, the connection portion can be located in the contact portion 33 where the outer members 36 contact each other.

[0102] A reinforcing portion 35 can be formed inside the outer member 36, and the reinforcing portion 35 can be formed to pass through the internal closed cross-section of the outer member 36, and can be formed to have a reinforcing flange 35a and can be connected to the outer member 36 in the reinforcing flange 35a.

[0103] When the reinforcing flange 35a is connected to the outer member 36 provided at the upper end portion of the vehicle in the height direction, the reinforcing flange 35a can be arranged to face upward, and when the reinforcing flange 35a is connected to the outer member 36 provided at its lower end portion, the reinforcing flange 35a can be arranged to face downward.

[0104] The third sub-frame 30 can be formed in the shape as described above, so that effects of effectively absorbing the impact in the forward direction of the vehicle, minimizing the impact transmitted to the first sub-frame 10, and reducing the weight can be provided.

[0105] The third sub-frame 30 is not limited to the shape as described above and can be variably changed according to the design.

[0106] Although the example embodiments have been described and illustrated above, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope of the present disclosure as defined by the appended claims.

[0107] Description of Reference Numerals

[0108] 10: First sub-frame 20: Second sub-frame

[0109] 21: First side member 21a: First groove

[0110] 22: Second side member 22a: Second groove

[0111] 30: Third sub-frame 31: First auxiliary member

[0112] 32: Second auxiliary member 33: Contact portion

[0113] 34, 35: Reinforcing portions 36: Outer member

[0114] 40: Upper spring sheet 50: Mounting bracket

[0115] 60: Connecting member 70: End plate

[0116] 100: Battery frame 200: Front frame

[0117] 300: Rear frame 400: Bottom plate

[0118] 500: Lateral member 600: Bottom frame beam

Claims

1. An electric vehicle body structure, comprising: a battery frame that is formed to surround a battery area including a battery; and a front frame that is disposed on the battery frame at a front side portion of the vehicle, wherein the front frame includes: a first sub-frame that is connected to the battery frame, a second sub-frame that branches from the first sub-frame and inclines outward in a width direction of the vehicle; and a third sub-frame that extends from the first sub-frame at a front portion of the vehicle farther than a branching point of the second sub-frame.

2. The electric vehicle body structure according to claim 1, wherein, The second sub-frame and the third sub-frame are disposed at the same position in a height direction of the vehicle.

3. The electric vehicle body structure according to claim 1, wherein, A cross-section of the second sub-frame or the third sub-frame includes a plurality of closed cross-sections.

4. The electric vehicle body structure according to claim 1, wherein, The second sub-frame includes: a first side member that extends in a longitudinal direction of the vehicle and includes a first groove formed in a width direction of the vehicle, and a second side member that extends in the longitudinal direction of the vehicle and is coupled to the first side member to form a closed cross-section, and includes a second groove formed toward the closed cross-section in the width direction of the vehicle, wherein the first groove and the second groove are in contact with each other.

5. The electric vehicle body structure according to claim 4, wherein, The first side member is disposed outside the second side member in the width direction, a first flat portion parallel to the second side member is formed, and a shortest distance from the first flat portion to the first groove in the width direction increases toward a front portion of the vehicle.

6. The electric vehicle body structure according to claim 3, wherein, The third sub-frame has a polygonal cross-section structure that is symmetric in a height direction of the vehicle.

7. The electric vehicle body structure according to claim 6, wherein, The third sub-frame further includes a reinforcing portion passing through the closed cross-section.

8. The electric vehicle body structure according to claim 6, wherein, The third sub-frame includes: a first auxiliary member that is disposed at an end portion in the height direction of the vehicle, and a second auxiliary member that is coupled to the first auxiliary member and has a contact portion that contacts at least one surface of the formed second auxiliary member.

9. The electric vehicle body structure according to claim 6, wherein, The third sub-frame includes: an outer member that has a hollow space formed therein and is integrally provided.

10. The electric vehicle body structure according to claim 1, further comprising: a mounting bracket that is coupled to the first sub-frame, and a spring upper leaf that is coupled to the mounting bracket.

11. The electric vehicle body structure according to claim 1, wherein, The strength of the first sub-frame is greater than the strength of the second sub-frame and the third sub-frame, and the thickness of the first sub-frame is thicker than the thickness of the second sub-frame and the third sub-frame.

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