Structural Battery With Reduced Sill Height

Abstract

An electric vehicle includes: a frame with two spaced-apart longitudinal members having an upper transversely oriented wall member that is situated a vertical distance Hu from a bottom plane and a lower transversely oriented wall member that is situated near the bottom plane, and a battery pack with an array of battery cells defining an array top surface, an array bottom surface and an array side surface. A casing top plate contacts the array top surface, a casing bottom plate contacting the array bottom surface and a casing side wall, connected to the top and bottom plates and contacting the array side surface. The casing top plate is situated a vertical distance Hct from the bottom plane that substantially corresponds with the distance Hu. The battery pack includes a longitudinal impact absorption structure.

Claims

1. An electric vehicle, comprising: a frame with two spaced-apart longitudinal members having an upper transversely oriented wall member that is situated a vertical distance Hu from a bottom plane and a lower transversely oriented wall member that is situated near the bottom plane, and a battery pack with an array of battery cells defining an array top surface, an array bottom surface and an array side surface, a casing top plate contacting the array top surface, a casing bottom plate contacting the array bottom surface and a casing side wall, connected to the top and bottom plates and contacting the array side surface, the casing top plate being situated a vertical distance Hct from the bottom plane that substantially corresponds with the distance Hu, the battery pack comprising a longitudinal impact absorption structure comprising the casing side wall and a reinforcement section extending outwardly from the side wall to a position near the adjacent longitudinal member and having a lower part, connected to the longitudinal member at a height near the lower wall member, and an upper part, connected to the longitudinal member near the upper wall member.

2. The electric vehicle according to claim 1, wherein the lower part of the reinforcement section extends below the lower wall member of the longitudinal member and is connected to the lower wall member via a bolt connection.

3. The electric vehicle according to claim 1, wherein the upper part of the reinforcement section extends below an upper wall of the longitudinal member and is connected to the upper wall via a bolt connection.

4. The electric vehicle according to claim 1, wherein an upper part of the longitudinal members extends a distance H.sub.wc above the plane of the top plate that is not higher than 10 cm.

5. The electric vehicle according to claim 4, wherein no cross beams extend between the longitudinal members at the level of the top plate.

6. The electric vehicle according to claim 1, the top plate, bottom plate and side walls being adhesively connected to the array top surface, the array bottom surface and the array side surfaces, respectively.

7. A battery pack, comprising an array of battery cells defining an array top surface, an array bottom surface and an array side surface, a casing top plate contacting the array top surface, a casing bottom plate defining a bottom plane and contacting the array bottom surface, and a casing side wall, connected to the top and bottom plates and contacting the array side surface, the battery pack comprising a longitudinal impact absorption structure comprising the casing side wall and a reinforcement section extending outwardly from the side wall and having a lower part with a connection member for connecting to a longitudinal sill member at a height near the bottom plane, and an upper part with a connection member that is adapted to be connected to a longitudinal sill member near the top plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] An embodiment of an electric vehicle having a battery pack assembly according to the application, will, by way of non-limiting example, be described in detail with reference to the accompanying drawings. In the drawings:

[0022] FIG. 1 shows a frame 1 of an electric vehicle according to the application,

[0023] FIG. 2 shows a frame in accordance with the prior art,

[0024] FIG. 3 shows the frame of FIG. 1 with the battery pack connected to the side profiles,

[0025] FIG. 4 shows a transverse cross-sectional view of the frame of FIG. 3 looking in a forward direction, and

[0026] FIG. 5 shows the distribution of the forces that act upon a side impact on the frame of FIG. 4.

DESCRIPTION OF EMBODIMENTS

[0027] FIG. 1 shows a frame 1 of an electric vehicle according to the application, including a front frame structure 2, a rear frame structure 3, including a rear floor, and a structural battery assembly 4 forming a bottom structure 5 of the vehicle. The structural battery assembly 4 includes longitudinal sill profiles 6,7 that interconnect the front and rear frame structures 2,3 and that support a structural battery pack 9 of interconnected battery cells. The top plate 10 of the battery pack forms the bottom of the cabin of the vehicle.

[0028] FIG. 2 shows a known frame 19 of an electric vehicle including a bottom plate 11 that is attached to a front frame structure 12 and to a rear frame structure 13. A battery pack is placed below the bottom plate 11. Two longitudinal sill members, or rockers, 14, 15 are interconnected by side-spanning members 16,17, 18 that are connected to the bottom plate 11 by spot welding or by mechanical fasteners.

[0029] FIG. 3 shows the frame 1 of FIG. 1 according to the disclosure, with the battery pack 9 connected to the transverse members 6,7, that extend only a low height above the top plate 10 of the battery pack 9, forming a low sill structure.

[0030] FIG. 4 shows the battery pack 9 with the top plate 10, the bottom plate 20 and the side wall 21 of the casing that encloses the battery cells 22,23. The battery cells 22,23 are placed in an array of for instance 4×40 cells, and define an array top surface 30, an array bottom surface 31 and an array side surface 32. The surfaces 30-32 are connected via adhesive connection areas 25,26 and 27 to the bottom plate 20, to the side wall 21 and to the top wall 10 respectively. Adhesive areas 28 interconnect the battery cells 22,23.

[0031] The side wall 21 of the casing is connected to a longitudinal impact absorption structure 40 with an upper part 41 that is situated at a vertical distance H.sub.tc of 15 cm above a bottom plane 42. The upper part 41 extends to a lateral position that is adjacent an inner surface 43 of the longitudinal sill profile 7. The upper part 45 of the sill profile 7 has a transversely extending reinforcement plate 46 that is situated at a height Hu above the bottom plane 42, that is about equal to the height Hat. A further upper reinforcement plate 47 that is closer to the bottom plane 42, is situated at substantially the same height as an underlying reinforcement plate 48 of the impact absorption structure 40. The top of wind cord 49 that forms part of the longitudinal sill profile 7, extends a distance H.sub.wc above the top plate 10 of about 8.5 cm.

[0032] FIG. 5 shows the upper part 53 of the sill profile 7 being connected to the upper part 41 of the impact absorption structure 40 via a bolt 54. The lower part 50 of the sill profile 7 is connected to a lower part 51 of the structure 40 via a bolt 52. The forces that act upon a side impact at the profile 7 are shown to be transferred via the upper reinforcement plate 46 of the sill profile 7 to the upper part 41 of the impact absorption structure 40 and from there to the top plate 10 of the battery casing. Forces are transferred from the lower part 50 of the sill profile 7 to the lower part 51 of the impact absorption structure 40 and from there on to the bottom plate 20. A height Z may be between 20 and 30 cm, for instance 22 cm, whereas a length Y may be between 20 and 30 cm, for instance 24 cm.