Busbar assembly

Abstract

A busbar assembly comprises an elongated support structure with a bottom, two side walls, extending in a length direction (L) along longitudinal sides, two spaced-apart central ridges extending in the length direction (L), a signal line, connected to the support structure between the central ridges, conductor members positioned between the side walls and an adjacent central ridge, adapted for interconnecting terminals of battery cells that are adjacent when seen in the length direction (L). The sidewalls and the ridges each extend at a cover side of the bottom and define top adhesive surface strips with respective widths Ws, Wc, the strips being situated in a connecting plane and adapted for adhesive connection to a top plate of a battery pack casing.

Claims

1. A busbar assembly comprising: an elongated support structure having a length direction (L) and a defined width (W), the support structure comprising: a bottom, two side walls, extending in the length direction (L) along longitudinal sides, two spaced-apart central ridges extending in the length direction (L), a signal line, connected to the support structure between the central ridges, conductor members positioned between the side walls and an adjacent central ridge, adapted for interconnecting terminals of battery cells that are adjacent in the length direction (L), the sidewalls and the ridges each extending at a cover side from a bottom to a connecting plane and defining a top adhesive surface strip with respective widths Ws, Wc, the strips being situated in said connecting plane and adapted for adhesive connection to a top plate of a battery pack casing.

2. The busbar assembly according to claim 1, the sidewalls and central ridges extending substantially along the length of the bottom of the support structure and having a height (H) from the bottom that is higher than a height of the conductor members, for forming respective gas channels extending in the length direction (L) between a top surface of the conductor members and the connecting plane and between a top surface of the signal line and the connecting plane.

3. The busbar assembly according to claim 1, the bottom comprising a bottom contact plane adapted for adhesive connection to battery cell top surfaces, a central part of the bottom that is situated between the ridges comprising apertures and being positioned at a distance above the bottom contact plane, forming an accommodation space at a battery facing surface of the bottom, in which the signal line is arranged to be received.

4. The busbar assembly according to claim 3, the central part of the bottom having at the battery facing side two stepped side edges, two rims extending in the length direction, on the battery facing side of the central part of the bottom, forming an adhesive accommodation channel between each stepped side edges and the respective rims.

5. The busbar assembly according to claim 3, the bottom contact plane comprising adhesive surface strips that extend parallel to the top adhesive surface strips.

6. A battery pack comprising: a casing with a bottom wall, two side walls and a top wall, a number of rows of interconnected prismatic battery cells, each cell having in a top plane two spaced-apart electric terminals, the battery cells in each row being attached to a respective busbar assembly, side surfaces of the battery cells in an outer row of battery cells being adhesively connected to a casing side wall, the top walls of the battery cells being adhesively connected to the support structure and the top wall of the casing being adhesively connected to the support structure and being connected to the sidewalls, and wherein the busbar assembly comprises: an elongated support structure having a length direction (L) and a defined width (W), the support structure comprising: a bottom, two side walls, extending in the length direction (L) along longitudinal sides, two spaced-apart central ridges extending in the length direction (L), a signal line, connected to the support structure between the central ridges, conductor members positioned between the side walls and an adjacent central ridge, adapted for interconnecting terminals of battery cells that are adjacent in the length direction (L), the sidewalls and the ridges each extending at a cover side from a bottom to a connecting plane and defining a top adhesive surface strip with respective widths Ws, Wc, the strips being situated in said connecting plane and adapted for adhesive connection to a top plate of a battery pack casing.

7. An electric vehicle comprising: a battery pack comprising: a casing with a bottom wall, two side walls and a top wall, a number of rows of interconnected prismatic battery cells, each cell having in a top plane two spaced-apart electric terminals, the battery cells in each row being attached to a respective busbar assembly, side surfaces of the battery cells in an outer row of battery cells being adhesively connected to a casing side wall, the top walls of the battery cells being adhesively connected to the support structure and the top wall of the casing being adhesively connected to the support structure and being connected to the sidewalls, and wherein the busbar assembly comprises: an elongated support structure having a length direction (L) and a defined width (W), the support structure comprising: a bottom, two side walls, extending in the length direction (L) along longitudinal sides, two spaced-apart central ridges extending in the length direction (L), a signal line, connected to the support structure between the central ridges, conductor members positioned between the side walls and an adjacent central ridge, adapted for interconnecting terminals of battery cells that are adjacent in the length direction (L), the sidewalls and the ridges each extending at a cover side from a bottom to a connecting plane and defining a top adhesive surface strip with respective widths Ws, Wc, the strips being situated in said connecting plane and adapted for adhesive connection to a top plate of a battery pack casing.

8. A method of manufacturing a battery pack, the method comprising: providing at least one row of prismatic battery cells, providing a busbar assembly, applying adhesive onto the bottom, connecting the busbar assembly to a top surface of the rows of battery cells, via the adhesive, providing adhesive on the top adhesive surface strips, and placing a casing cover on the top adhesive surface strips and connecting the casing cover via the adhesive, wherein the busbar assembly comprises: an elongated support structure having a length direction (L) and a defined width (W), the support structure comprising: a bottom, two side walls, extending in the length direction (L) along longitudinal sides, two spaced-apart central ridges extending in the length direction (L), a signal line, connected to the support structure between the central ridges, conductor members positioned between the side walls and an adjacent central ridge, adapted for interconnecting terminals of battery cells that are adjacent in the length direction (L), the sidewalls and the ridges each extending at a cover side from a bottom to a connecting plane and defining a top adhesive surface strip with respective widths Ws, Wc, the strips being situated in said connecting plane and adapted for adhesive connection to a top plate of a battery pack casing.

9. The method of manufacturing according to claim 8, comprising providing a number of adjacent rows of prismatic battery cells, adhesively attaching a bottom plate of a casing to a bottom surface of the adjacent rows of battery cells, and adhesively attaching longitudinal side surfaces of outer rows of battery cells to longitudinal side walls of the casing.

10. The method according to claim 9, the cover of the casing being attached to the sidewalls via welding or brazing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] A busbar assembly according to the disclosure will, by way of non-limiting example, be described in detail with reference to the accompanying drawings. In the drawings:

[0042] FIG. 1 shows a structural battery pack connected to a front and rear frame part of an electric vehicle,

[0043] FIG. 2 shows a perspective view of a stack of battery cells and a busbar assembly, prior to adhesive connection of the busbar assembly,

[0044] FIG. 3 shows the stack of battery cells of FIG. 2, with the busbar assembly attached to a top surface of the stack,

[0045] FIG. 4 shows a perspective view of a battery pack, at the moment of connecting of the top cover,

[0046] FIG. 5 shows a perspective view on an enlarged scale of the busbar assembly, and

[0047] FIG. 6 shows a cross-sectional view of a part of the battery pack of FIG. 4.

DETAILED DESCRIPTION

[0048] FIG. 1 shows a frame 1 of an electric vehicle, comprising 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 comprises longitudinal sill profiles 6,7 that interconnect the front and rear frame structures 2,3 and that support a structural battery pack 9. The battery pack 9 houses cell stacks 11,12 of interconnected prismatic battery cells 13,14, the stacks extending in the length direction L. The terminals of the battery cells 13,14 in each stack 11,12 are interconnected by bus bar assemblies carrying voltage terminals and signal lines that connect to sensors measuring voltage and temperature in each cell 13, 14. The top cover plate 10 of the battery pack forms the bottom of the cabin of the vehicle.

[0049] FIG. 2 shows a cell stack 11 of prismatic battery cells 15,16,17 and a bus bar assembly 20 connected to a top surface 38 of the battery cells. The battery cells 15, 16, 17 are of a width W of between 25 cm and 35 cm and comprise terminals 24, 26; 25, 27. Terminals 24,25; 26;27 of adjacent battery cells 15,16 are interconnected via metal conductor members 22,23 of the busbar assembly 20.

[0050] The busbar assembly 20 comprises an elongated support structure 30 of a plastic material, carrying the metal conductor members 22,23 and a signal line 31 formed by a flexible PCB that comprises a number of conductive paths interconnecting temperature and voltage sensors on each battery cell 15, 16, 17. The support structure 30 comprises upstanding side walls 33,34 and central ridges 35, 36. The signal line 31 is supported on the bottom side of the support structure 30, in a central area between the ridges 35,36.

[0051] Ventilation apertures 39, 40 are provided in the bottom of the central area of the support structure 30, for removal of gases from the battery cells that may be released in case of a thermal event. The bottom of the support structure 30 is adhesively connected to the top surface 38 of the battery cell stack 11.

[0052] As shown in FIG. 3, the sidewalls 33,34 and central ridges 35,36 form adhesive surfaces 45, 46, 47, 48, defining a connecting plane 41 for connecting to a top cover of the battery pack 9, that are schematically indicated by the dashed lines in the figure.

[0053] FIG. 4 shows the battery pack 9 with four battery cell stacks 11,12 that are mounted in a compressed state between front and rear transverse beams 50, 51 that are interconnected by the sill profiles 6,7. The top cover plate 10 is adhesively connected to the busbar assembly 20 of each stack 11, 12 of battery cells along the adhesive surfaces 45, 46, 47, 48, 49. After adhesive connection of the top cover plate 10 to the busbar assemblies 20, the cover plate is connected to the sill profiles 6,7 and to the front and rear transverse beams 50,51 by welding or brazing, to form a protective enclosure that prevents the ingress of moisture or particulate matter.

[0054] FIG. 5 shows an enlarged perspective view of the busbar assembly 20 and the area between the central ridges 35,36. The area between the central ridges 35, 36 forms a ventilation channel 52 extending in the length direction L for the removal of gases, that enter into the channel via the apertures 39, 40 and flow in the direction of the arrows v1, v2. The gases are contained in the channel 52 by the central ridges 35,36 that prevent spreading of the gases in a transverse direction. The central ventilation channel 52 connects to ventilation apertures in the front and rear transverse beams 50,51.

[0055] FIG. 6 shows battery cell 15 with terminals 24, 26 connected to conductor members 22, 23 of the busbar assembly 20. The side walls 33, 34 and the central ridges 35, 36 define the connecting plane 41 in which the top cover 10 is attached along strips 33′, 34′, 35′, 36′ via an adhesive connection. The gas vent channel 52 extends in the length direction L, that is perpendicular to the plane of the drawing, and is defined between the central ridges 35, 36 and the top cover 10 of the casing. The height H of the sidewalls 33, 34 above the bottom 55 of the support structure 30 may be 1.5 cm-5 cm, leaving space above the conductor members 22,23 forming a channel 53, isolating conductive gases that are generated in case of a thermal event.

[0056] The bottom 55 of the support structure 30 is adhesively connected to the top surface 38 of the battery cell 15 along adhesive strips 33″ and 34″ that are situated vertically below the adhesive strips 33′, 34′. The side surface 56 of the battery cell 15 is adhesively connected to the wall of the sill profile 6 of the casing, and the side surface 57 of battery cell 15 is glued to the adjacent battery cell 19. The bottom surface 57 of the cell 15 is glued to bottom plate 58 of the battery pack casing.

[0057] The bottom 55 of the support structure 30 comprises at the central ridges 35, 36 a stepped part 60, 61 and a parallel rim 62, 63, at a transverse distance from the stepped parts 60, 61, thus defining a groove for containing the adhesive during connection of the busbar assembly to the battery cells. The signal line (not shown in the drawing) is accommodated in the space 65 between the rims 62, 63, below the gas vent channel 52.

[0058] The width Ws of the sidewalls 33, 34 may be between 1 cm and 5 cm and the width Wc of the central ridges 35, 36 may be between 0.5 cm and 3 cm for a strong connection of the battery cell 15 to the top cover 10.