Electric vehicle body structure for improving the mechanical strength of a battery tray

Abstract

One aspect of the invention relates to an electric vehicle body structure (1) comprising: a third longitudinal member (12) secured to a floor panel (2), the third longitudinal member (12) extending longitudinally on an upper surface (4) of the floor panel (2) between floor (10) and rear axle (11) crossmembers; a fastening tab (13) originating at the third longitudinal member (12) and extending towards a battery tray (15), the fastening tab (13) opening into a space under the floor panel (2) and being positioned facing a single reinforcing crossmember 74, the fastening tab (13) comprising second means for securing the battery tray (15) and a branch box (17) to the body structure (1).

Description

DESCRIPTION TITLE: ELECTRIC VEHICLE BODY STRUCTURE IMPROVING THE MECHANICAL STRENGTH OF A BATTERY TRAY

[0001] The present invention claims priority from French application No. 2405150 filed on 21.05.2024, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002]

[0003] The present invention relates to an electric vehicle body structure that improves the mechanical strength of a battery tray. The technical field of the invention is therefore that of battery trays.

[0004] As described in document CN-U-218849678, some electric vehicles have a body structure under which a set of lithium-ion type battery modules is mounted.

[0005] As illustrated in Figure 1, which represents a longitudinal section of a body structure 100, in a manner known per se, this type of electric vehicle comprises a body structure 100 equipped with a floor panel 101, a pair of longitudinal members 102 (only one is shown) extending longitudinally along the right and left sides of the floor panel 101, and reinforcing cross members 103 extending between said longitudinal members 102.

[0006] In the illustrated example, the body structure 100 comprises four reinforcing cross members 103. The body structure 100 also includes a battery tray 104 containing, in the illustrated example, four battery modules 105i, 1052, 105s, 1054, each of the four battery modules 105i, 1052, 105s, 1054 extending longitudinally in the transverse direction of the body structure 100. Three of the four battery modules 105i, 1052, 105s are secured to two reinforcing cross members 103. The fourth battery module 1054, located at the rear of the body structure 100, is secured to a single reinforcing cross member 103. The fastening is achieved by screws 106, the heads of which bear against the wall of the battery tray 104 and which the body passes through a tab 107 which is present in each battery module 105i, 1052, 105s, 1054 to screw into a thread (not shown) which is present in each of the reinforcing cross members 103.

[0007] At the rear of the fourth battery module 1054 is a junction box 108 which integrates fuses and relays for controlling the electrical part of the battery modules 105i, 1052, 105s, 1054.

[0008] Due to the limited space under the vehicle's floor panel 101, no cross member is provided between the fourth module 1054 and the junction box 108. However, as the rear of the fourth module 1054 is not secured to any reinforcing cross member 103, the weight of the fourth module 1054, approximately 75 kg, generates a downward force multiplied by a coefficient due to the vehicle's accelerations and the vertical movements of the body structure 100. This force risks deforming the battery tray 104, or even breaking it.

[0009] The invention offers a solution to the problems mentioned above, by proposing an electric vehicle body structure that improves the mechanical strength of the battery tray.

[0010] In this context, the invention, in its broadest sense, relates to an electric vehicle body structure comprising: A floor panel having a lower surface intended to be positioned opposite a battery tray and an upper surface forming a vehicle floor; A first and a second stringer attached to said floor panel and extending longitudinally respectively along the right and left side of the floor panel; An even number of reinforcing cross members attached to the floor panel, the reinforcing cross members extending transversely over the lower surface between the first and second longitudinal members, each of the reinforcing cross members having first means of attaching a battery tray and battery module to the body structure; A floor crossmember and a rear axle crossmember attached to the floor panel, the floor and rear axle crossmembers extending transversely over the upper surface between the first and second longitudinal members.

[0011] The case structure according to this aspect of the invention is remarkable in that it also comprises: A third longitudinal member attached to the floor panel, the third longitudinal member extending longitudinally over the upper surface between the floor and rear axle cross members; A fixing bracket originating at the level of the third longitudinal member and exiting under the floor panel on the side of the lower surface, the fixing bracket being positioned opposite one of the reinforcing cross members, the fixing bracket including second means of securing the battery tray and a junction box to the body structure.

[0012] Thanks to the invention, and more specifically the integration of a third longitudinal member to which a mounting bracket is attached, a new mounting point for the battery tray is introduced. This new mounting point allows for the attachment of not only the battery tray but also the junction box. Positioned at the rear of the battery module, which is attached only to a reinforcing crossmember, this mounting bracket absorbs the forces generated by the battery module and consequently improves the mechanical strength of the battery tray.

[0013] In addition to the characteristics mentioned in the preceding paragraph, the box structure according to this aspect of the invention may have one or more additional characteristics from among the following, considered individually or according to all technically possible combinations.

[0014] According to a non-limiting aspect of the invention, the fixing bracket forms a U or a V whose arms are secured to the third longitudinal member.

[0015] According to a non-limiting aspect of the invention, the third side member is welded to the floor panel, the floor cross member and the rear axle cross member.

[0016] According to a non-limiting aspect of the invention, the third spar has a wall whose thickness is between 1 mm and 1.6 mm.

[0017] According to a non-limiting aspect of the invention, the fixing bracket is welded to the floor panel and to the third longitudinal member.

[0018] According to a non-limiting aspect of the invention, the fixing bracket has a wall whose thickness is between 1.5 mm and 2.1 mm.

[0019] According to a non-limiting aspect of the invention, the body structure comprises a battery tray equipped with an even number of battery modules equal to the even number of reinforcing cross members and a junction box, each space formed between two reinforcing cross members being filled by one of the battery modules and only one of said battery modules being positioned between one of the reinforcing cross members and said junction box, the junction box being positioned opposite the fixing bracket and the junction box having a recess in which said fixing bracket is positioned, the battery tray and the battery modules being secured to said body structure via first fixing means cooperating with the first fastening means comprising said reinforcing cross members,The battery tray and junction box are secured to the body structure via secondary fastening means cooperating with the secondary fastening means included in the mounting bracket.

[0020] According to a non-limiting aspect of the invention, the second means of securing which comprise the fixing bracket are formed by an internal thread and the second means of fixing are formed by a screw whose head bears against the battery tray, the transverse body against the junction box and the thread is screwed into the internal thread which comprises the fixing bracket.

[0021] According to a non-limiting aspect of the invention, the first means of securing the reinforcement cross members are formed by internal threads and the first means of fixing are formed by screws, for each of said screws, the head bears on the battery tray, the transverse body on a fixing support included in one of the battery modules and the thread is screwed into one of the internal threads included in the reinforcement cross members.

[0022] Another aspect of the invention relates to an electric vehicle comprising a body structure according to any one of the aforementioned aspects of the invention.

[0023] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0024] [Fig. 1] illustrates, schematically, a longitudinal section of an electric vehicle body structure according to the state of the art.

[0025] [Fig. 2] illustrates, schematically, a longitudinal section of an electric vehicle body structure according to the invention.

[0026] [Fig. 3] illustrates, schematically, a view from below of the body structure of an electric vehicle according to the invention.

[0027] [Fig. 4] illustrates, schematically, a top view of the electric vehicle body structure according to the invention.

[0028] [Fig. 5] illustrates, schematically, a fixing bracket that includes the body structure of an electric vehicle according to the invention.

[0029] [Fig. 6] illustrates, schematically, a longitudinal section of a box structure equipped with a battery tray according to the invention.

[0030] [Fig. 7] illustrates, schematically, a bottom view of the car body structure equipped with battery modules according to the invention.

[0031] The figures are presented for illustrative purposes only and are in no way limiting to the invention.

[0032] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0033] Figure 2 schematically illustrates a longitudinal section of a body structure 1 of an electric vehicle according to the invention. It should be noted that the battery tray is not shown.

[0034] The body structure 1 includes a floor panel 2 having a lower surface 3 intended to be positioned opposite a battery tray and an upper surface 4 forming a vehicle floor.

[0035] As shown in Figure 3 illustrating a bottom view of the body structure 1, the latter comprises a first longitudinal member 5 and a second longitudinal member 6 attached to the floor panel 2. The first longitudinal member 5 extends longitudinally along the right side of the floor panel 2 and the second longitudinal member 6 extends longitudinally along the left side of the floor panel 2.

[0036] The body structure 1 is also equipped with an even number of reinforcing cross members 7i, 72, 7s, 74 (here four) attached to the floor panel 2. More specifically, the reinforcing cross members 7i, 72, 7s, 74 extend transversely over the lower surface 3 of the floor panel 2 between the first stringer 5 and the second stringer 6.

[0037] In addition, each of the reinforcing cross members 7i, 72, 7s, 74 includes first means of securing 8 a battery tray and battery modules to the body structure 1.

[0038] According to a non-limiting aspect, the first fastening means 8 are formed by internal threads. According to a non-limiting aspect of the invention, the reinforcing cross members 7i, 72, 7s, 74 are hollow and each internal thread is formed by a nut welded to a lower wall 9 of the reinforcing cross members 7i, 72, 7s, 74.

[0039] As shown in Figure 4, illustrating a top view of the body structure 1, the latter comprises a floor crossmember 10 and a rear axle crossmember 11 arranged opposite each other. The floor crossmember 10 and the rear axle crossmember 11 are integral with the floor panel 2. The floor crossmembers 10 and 11 extend transversely across the upper surface 4 between the first and second side members 5, 6.

[0040] The body structure 1 further includes a third longitudinal member 12 attached to the floor panel 2. The third longitudinal member 12 extends longitudinally over the upper surface 4 between the floor cross member 10 and the rear axle cross member 11.

[0041] According to a non-limiting aspect of the invention, the third side member 12 is welded to the floor panel 2, the floor cross member 10 and the rear axle cross member 11. This third side member 12 may have a wall with a thickness of between 1 mm and 1.6 mm, typically 1.3 mm.

[0042] The body structure 1 according to the invention also includes a fixing bracket 13. This fixing bracket 13 originates at the level of the third longitudinal member 12 and extends towards the battery tray, i.e. below the lower surface 3 of the floor panel 2. The fixing bracket 13 opens into a space under the floor panel 2 delimited by only one of the reinforcing cross members, namely the fourth reinforcing cross member 74. In other words, the fixing bracket 13 is located at the rear of the body structure 1.

[0043] As illustrated in figure 5, the fixing bracket 13 can form a U whose arms are secured to the third longitudinal member 12.

[0044] The branches can be joined to the third longitudinal member 12 and to the floor panel 2 by welding.

[0045] According to a non-limiting aspect, the fixing bracket 13 has a wall with a thickness between 1.5 mm and 2.1 mm, typically 1.8 mm.

[0046] The mounting bracket 13 includes second means for securing the battery tray and a junction box to the body structure 1. According to a non-limiting aspect, the second means for securing 14 that the mounting bracket 13 includes are formed by an internal thread.

[0047] According to a non-limiting aspect of the invention, the internal thread 14 is formed by a nut welded to the wall joining the two arms of the U.

[0048] Figure 6 schematically illustrates a longitudinal section of a box structure 1 equipped with a battery tray according to the invention.

[0049] The body structure 1 includes a battery tray 15 containing an even number (here four) of battery modules 161, 162, 163, 164 equal to the even number (here four) of reinforcing cross members 7i, 72, 7s, 74 and a junction box 17.

[0050] According to a different non-limiting embodiment, the even number of battery modules 161, 162, 163, 164 and the even number of reinforcing cross members 7i, 72, 7s, 74 can be two, six or eight.

[0051] Each of the three spaces 18 formed between two reinforcing crossbeams 7I-72, 72-7s and 73-74 is filled by one of the battery modules, respectively 161, 162, I63.

[0052] On the other hand, only one of the battery modules, namely the fourth battery module I64, is positioned between one of the reinforcement cross members 74 and the junction box 17.

[0053] It should also be noted that the junction box 17 is positioned opposite the mounting bracket 13 and the junction box 17 has a recess 19 into which the mounting bracket 13 is fitted,

[0054] The battery tray 15 and the battery modules 161, 162, 163, 164 are secured to the body structure 1 via initial fastening means 20, for example screws, cooperating with the internal threads 8 in the reinforcing cross members 7i, 72, 7s, 74. Furthermore, the battery tray 15 and the junction box 17 are secured to the structure of the case 1 via second means of fixing 21, for example a screw, cooperating with the internal thread 14 which has the fixing tab 13.

[0055] For each screw 20, the head rests on the battery tray 15, the transverse body on a fixing support 22 which includes one of the battery modules 161, 162, 163, 164 and the thread is screwed into one of the internal threads 8 which includes the reinforcing cross members 71, 72, 73, 74.

[0056] As shown in Figure 7 illustrating a bottom view of the body structure 1 equipped with battery modules I61, 162, 163, I64, each mounting bracket 22 originates at the body of one of the battery modules I61, 162, 163, I64 and extends towards one of the reinforcing cross members 7i, 72, 7s, 74. Each mounting bracket 22 has an opening 23 located opposite an internal thread 8 of one of the reinforcing cross members 7i, 72, 7s, 74. Each opening 23 allows the passage of the body of one of the screws 20.

[0057] As regards screw 21, the head rests on the battery tray 15, the body passes through the junction box 17 and the thread of screw 21 is screwed into the internal thread 14 which has the fixing tab 13.

[0058] Thanks to the invention, it is not necessary to add a fifth reinforcing crossmember placed behind the fourth battery module 164. This solution therefore makes it possible to optimize the space inside the battery box 15 in order to integrate the largest possible battery modules in order to offer the greatest possible autonomy for the vehicle.

[0059] Furthermore, as the junction box 17 is fixed to the mounting bracket 13, the mounting bracket 17 is not in direct contact with the battery tray 15. Thus, this solution does not impact the volume of the junction box 17 and it is possible to integrate all the relays and fuses necessary for the proper functioning of a battery tray of an electric vehicle.

Claims

DEMANDS

1. Body structure (1) of an electric vehicle comprising: - A floor panel (2) having a lower surface (3) intended to be positioned opposite a battery tray (15) and an upper surface (4) forming a vehicle floor; - A first and a second stringer (5, 6) attached to said floor panel (2) and extending longitudinally respectively along the right and left side of said floor panel (2); - An even number of reinforcing cross members (7i, 72, 7s, 74) attached to said floor panel (2), said reinforcing cross members (7i, 72, 7s, 74) extending transversely over said lower surface (3) between said first and second longitudinal members (5, 6), each of said reinforcing cross members (7i, 72, 7s, 74) comprising first means of attaching (8) a battery tray (15) and battery modules (161, 162, 163, 164) to said body structure (1); - A floor crossmember (10) and a rear axle crossmember (11) integral with said floor panel (2), said floor crossmembers (10) and rear axle crossmembers (11) extending transversely over said upper surface (4) between said first and second longitudinal members (5, 6), said body structure (1) being characterized in that it further comprises: - A third longitudinal member (12) attached to said floor panel (2), said third longitudinal member (12) extending longitudinally over said upper surface (4) between said floor cross members (10) and rear axle cross members (11); - A mounting bracket (13) originating at the level of said third longitudinal member (12) and extending under said floor panel (2) on the side of the lower surface (3), said mounting bracket (13) being positioned opposite one of the reinforcing cross members (74), said mounting bracket (13) comprising secondary means for securing said battery tray (14) (15) and a junction box (17) to said case structure (1).

2. Body structure (1) according to the preceding claim, characterized in that the fixing bracket (13) forms a U or a V whose arms are attached to the third longitudinal member (12).

3. Body structure (1) according to any one of the preceding claims, characterized in that the third longitudinal member (12) is welded to the floor panel (2), the floor cross member (10) and the rear axle cross member (11).

4. Body structure (1) according to any one of the preceding claims, characterized in that the third side member (12) has a wall whose thickness is between 1 mm and 1.6 mm.

5. Body structure (1) according to any one of the preceding claims, characterized in that the fixing tab (13) is welded to the floor panel (2) and to the third longitudinal member (12).

6. Carcass structure (1) according to any one of the preceding claims, characterized in that the fixing tab (13) has a wall whose thickness is between 1.5 mm and 2.1 mm.

7. Body structure (1) according to any one of the preceding claims, characterized in that it comprises a battery tray (15) equipped with an even number of battery modules (16i, 162, 163, 164) equal to the even number of reinforcing cross members (7i, 72, 7s, 74) and a junction box (17), each space (18) formed between two reinforcing cross members (7i, 72, 7s) being filled by one of said battery modules (161, 162, 163) and only one of said battery modules (164) being positioned between one of the reinforcing cross members (74) and said junction box (17), said junction box (17) being positioned opposite said mounting bracket (13) and said junction box (17) having a recess (19) in which is positioned said mounting bracket (13), said battery tray (15) and said battery modules (161, 162, 163,I64) being secured to said body structure (1) via first fastening means (20) cooperating with the first fastening means (8) comprising said reinforcing cross members (7i, 72, 7s, 74), said battery tray (15) and said junction box (17) being secured to said body structure (1) via, second fastening means (21) cooperating with the second fastening means (14) included in said fastening tab (13). [Claims] Car body structure (1) according to the preceding claim, characterized in that the second fastening means (14) which comprise the fixing tab (13) are formed by an internal thread and the second fixing means (21) are formed by a screw whose head bears on the battery tray (15), the transverse body on the junction box (17) and the thread is screwed into the internal thread which comprises the fixing tab (13).

9. Body structure (1) according to any one of claims 7 or 8, characterized in that the first means of securing (8) which comprise the reinforcing cross members (7i, 72, 7s, 74) are formed by internal threads and the first means of fixing (20) are formed by screws, for each of said screws, the head bears on the battery tray (15), the transverse body on a fixing support (22) which comprises one of the battery modules (161, 162, 163, 164) and the thread is screwed into one of the internal threads which comprise the reinforcing cross members (7i, 72, 7s, A).

10. Electric vehicle, characterized in that it comprises a body structure (1) according to any one of the preceding claims.

Images