Structural Battery for an Electric Vehicle Comprising a Battery Cell Support Matrix

Abstract

An electric vehicle including a battery assembly with at least two rows of battery cells attached to a battery frame structure. The battery frame structure has a number of accommodating cavities, arranged in a matrix, each battery cell being placed in a respective accommodating cavity and connected to adjacent walls of the respective accommodating cavity via a flowable bonding substance being inserted in a gap between the cells and the walls of the respective cavity.

Claims

1. An electric vehicle, comprising a battery assembly with at least two rows of battery cells attached to a battery frame structure, wherein the battery frame structure comprises a number of accommodating cavities, arranged in a matrix, each battery cell being placed in a respective accommodating cavity and connected to adjacent walls of the respective accommodating cavity via a flowable bonding substance being inserted in a gap between the cells and the walls of the respective cavity.

2. The electric vehicle according to claim 1, wherein the battery frame structure comprises longitudinal and transverse peripheral walls, the peripheral walls and the walls of the accommodating cavities being formed by injection molding, casting or additive manufacturing, of a first, solidifying material, the flowable bonding substance comprising a second substance.

3. The electric vehicle according to claim 1, wherein the accommodating cavities are of substantially the same height as a height of the battery cells, a bottom surface of the battery frame structure being substantially flat and supporting a thermally conductive layer contacting the bottom of each battery cell, a top surface of the battery frame structure being placed in a contacting relationship with a top cover.

4. The electric vehicle according to claim 1, wherein the battery frame structure is placed in a tray member comprising two longitudinal side profiles that are interconnected via a front and rear transverse beam, longitudinal peripheral walls of the battery frame structure extending at a distance from the longitudinal side profiles, a compressible filler member being placed between the longitudinal peripheral walls of the battery frame structure and the respective adjacent longitudinal side profile.

5. The electric vehicle according to claim 4, a top plate and a bottom plate being placed in contact with the top and bottom plane of the battery frame structure, the top and bottom plates being attached to the longitudinal side profiles forming a casing.

6. The electric vehicle according to claim 5, the bottom plate comprising a number of cooling channels extending in a length direction, the cooling channels being connected to a cooling fluid inlet at a first transverse beam and being connected to a cooling fluid outlet manifold at a second transverse beam.

7. The electric vehicle according to claim 6, the bottom plate being covered by an insulating layer forming the outer bottom layer of the vehicle.

8. The electric vehicle according to claim 5, the front and the rear peripheral walls of the battery frame structure contacting a respective parallel metal reinforcement plate contacting the front and rear peripheral walls and connected along its width to the front and rear transverse beams.

9. The electric vehicle according to claim 8, the front reinforcement plate comprising a centrally placed reinforcement member, preferably formed by extrusion, having a number of compartments.

10. A battery pack for use in an electric vehicle, the battery pack comprising at least two rows of battery cells attached to a battery frame structure with a number of accommodating cavities, arranged in a matrix, each battery cell being placed in a respective accommodating cavity and connected to adjacent walls of the respective accommodating cavity via a flowable bonding substance being inserted in a gap between the cells and the walls of the respective cavity, the battery frame structure being placed in a tray member comprising two longitudinal side profiles that are interconnected via a front and rear transverse beam, longitudinal peripheral walls of the battery frame structure extending at a distance from the longitudinal side profiles, a compressible filler member being placed between the longitudinal peripheral walls of the battery frame structure and the adjacent longitudinal side profile.

11. A method of manufacturing a battery assembly for an electric vehicle, the method comprising: forming a battery frame structure having longitudinal and transverse peripheral walls and comprising a number of accommodating cavities arranged in a matrix by injection molding, casting or additive manufacturing, inserting battery cells into the accommodating cavities, and filling up a gap between the cells and the walls of the respective cavity with a bonding material, connecting each battery cell to the walls of the respective cavity via the bonding material forming a unitary cell block.

12. The method according to claim 11, further comprising: placing the unitary cell block formed by the battery frame structure and the connected battery cells in a tray member comprising two longitudinal side profiles that are interconnected via a front and rear transverse beam, the longitudinal peripheral walls of the battery frame structure extending at a distance from the longitudinal side profiles, inserting a deformable member between the longitudinal peripheral walls of the battery frame structure and the adjacent longitudinal side profile, and placing a top plate and a bottom plate on the top and bottom surfaces of the battery frame structure.

13. The method according to claim 12, further comprising attaching the top and bottom plates to a vehicle frame.

14. The method according to claim 12, further comprising connecting the top and bottom plates to longitudinal side profiles, forming a casing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of a battery assembly according to the disclosure will, by way of non-limiting example, be explained in detail with reference to the accompanying drawings. In the drawings:

[0030] FIG. 1 shows a frame of an electric vehicle including a structural battery,

[0031] FIG. 2 shows a tray of a battery assembly according to the present disclosure,

[0032] FIG. 3 shows a battery frame structure carrying rows of battery cells,

[0033] FIG. 4 shows a battery frame structure according to the disclosure,

[0034] FIG. 5 shows a top view of an enlarged detail of the battery frame structure of FIG. 4,

[0035] FIG. 6 shows a battery assembly prior to placing the top cover,

[0036] FIG. 7 shows a battery pack according to the disclosure,

[0037] FIG. 8 shows a transverse cross-sectional view of the battery pack according to the present disclosure, in a forward viewing direction,

[0038] FIG. 9 shows an end plate for reinforcement of the battery frame structure, and

[0039] FIG. 10 shows a front part of the front frame section connected to the battery pack according to the disclosure via an anchor bracket.

DETAILED DESCRIPTION OF EMBODIMENTS

[0040] FIG. 1 shows a frame 1 of an electric vehicle including a body-in-white front frame structure 2, a body-in-white rear floor structure 3, including set or rockers 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 battery pack 9 of interconnected battery cells. Cross beams 11, 12 are connected, for instance via spot welding, to a top plate 10 of the battery pack 9 and extend in a transverse direction, interconnecting the sill profiles 6,7 and supporting front passenger seats.

[0041] FIG. 2 shows a tray 13 of the battery pack 9, having longitudinal side member 14,15 that are interconnected by front transverse beam 16 and rear and transverse beam 17. A metal bottom plate 18 with longitudinal cooling channels 19, 20 forms the bottom of the tray 13. A cooling inlet manifold 21 distributes cooling fluid to the channels 19,20 and an outlet manifold 22 at the rear removes the heated coolant from the channels and transports it to a heat exchanger. At the front transverse beam 16, connecting brackets 24, 25 are provided for providing a rigid connection of the tray 13 to the front frame structure 2.

[0042] FIG. 3 shows a battery frame structure 30 carrying four rows 31-34 of battery cells. Each individual cell is placed in a cavity 35, 36 of the battery frame structure 30 and is firmly held in place by a bonding substance that fills up the space between the walls of the cavities 35, 36 and the cell inside the cavity. The battery frame structure 30 has longitudinal and transverse peripheral walls 37, 38 and forms a matrix of interconnected battery cells that can be handled as a unit and that can be accurately positioned in the tray 13. The height of the peripheral walls 37, 38 and of the cavity walls substantially corresponds to the height of the battery cells 31-34, so that the top and bottom surfaces of the assembly of battery frame structure 30 and cells 31-34 is substantially planar.

[0043] FIG. 4 shows an enlarged detail of the battery frame structure 30 near the front transverse beam 16. The cells 39, 40 are enclosed within the walls 38,37,43, 44 and 37,43,44,45 of respective cavities of the battery frame structure. The gaps 41 and 42 between the cells 39, 40 and the cavity walls are filled with a bonding material, that may be formed by an adhesive material or an expanding compound that can flow and fill the gaps and that can expand and solidify to firmly bond the cells to the cavity walls. The expanding compound could provide a pre-compression on the individual battery cells.

[0044] FIG. 5 shows an adhesive layer 49 that is placed on top of the battery cells in the battery frame structure 30. The space between the longitudinal side members 14, 15 and the longitudinal peripheral walls 37 of the battery frame structure 30 is filled with a foam block or honeycomb structure 47,48.

[0045] As shown in FIG. 6, the battery pack 9 is completed by placing a metal top cover 50 over the battery frame structure 30 and attaching the top cover to the adhesive layer 49 and to the side members 14,15 to form a strong casing around the battery cells.

[0046] FIG. 7 shows the battery pack 9 connected to the sill profiles 6,7 and to the cross beams 11,12. Upon side impact at the sill profile 7, the transverse forces Fs are distributed along the longitudinal side member 15 to the shear planes that are defined by the lower plate 18 and upper plate of the top cover 50. A deformation zone with a transverse width D is formed by the sill profile 7, the side member 15 and the foam block or honeycomb material 48. The deformation zone protects the battery cells 31-34 upon side impact and prevents rupture of the cells and intrusion upon impact.

[0047] FIG. 8 shows an enlarged detail of a longitudinal venting channel 52 extending in a length direction over the cooling channels 19 in the bottom plate 18. In case of a thermal event, gases are evacuated through the venting channel 52 to the rear transverse beam 17, where the gases can escape to environment. Because the venting channel 52 is cooled by the cooling channels 19 in the cooling plate 18, the risk of burn-through is significantly reduced.

[0048] A replaceable insulation layer 53 can be provided over the cooling plate 18 to form the outer layer of the vehicle. The thermal isolation provided by the layer 53 mitigates the wind chill factor of the battery pack 9 by the environment and prevents uncontrolled heat transfer. In case the insulation layer 53 gets damaged, for instance in case of a de-road accident, it can be easily removed, inspected and serviced or replaced.

[0049] FIG. 9 shows a reinforcement metal end plate 55 that is attached to the transverse wall 38 of the battery frame structure and to the front transverse beam 16, via anchor brackets 56, 57. The reinforcement end plate 55 can counteract swelling of the battery cells upon ageing which may cause forces on the sidewalls of the transverse peripheral walls 38 of the battery frame structure 30 of 10-30 kN.

[0050] FIG. 10 shows a front frame part 65 of the vehicle that is attached via bolts 60,61 to the anchor bracket 56, and via a bolt 62 to the bracket 24 on the front transverse beam 16. The frontal impact force Ff is deflected downward to the anchor bracket 56. The anchor bracket 56 is arc welded to the end plate 55, and has a number of bonded shear planes that distribute the load across the surface of the anchor bracket across the end plate 55 thereby keeping intrusions of the battery cells in the battery frame structure within safe limits.