Cooling System for Busbars

Abstract

Cooling system for bus bars, in particular cell connectors or module connectors of batteries, comprising a bus bar with a first connection area for a pole of a first battery, a second connection area for a connection of an electrical component, an insulation encasing the bus bar between the connection areas, wherein the bus bar is free of the insulation at least in the two connection areas, characterized in that on a side facing away from the pole of at least one of the connection areas, a gel-shaped heat conducting agent is applied directly to the surface of the bus bar.

Claims

1-12. (canceled)

13. Cooling system for bus bars, in particular cell connectors or module connectors of batteries, comprising a busbar with a first connection area for a pole of a first battery, a second connection area for a connection of an electrical connection part, an insulation sheathing the busbar between the connection areas, wherein the busbar is free of the insulation at least in the two connection areas, wherein on a side facing away from the pole of at least one of the connection areas, a gel-shaped heat-conducting agent is applied directly to the surface of the busbar; wherein the heat conducting agent is guided through a housing opening to the outside of a housing and the bus bar comprises a cooling region between the two connection regions, wherein the insulation is removed in the cooling region and the heat conducting agent is applied directly to the cooling region.

14. Cooling system according to claim 13, wherein the heat-conducting agent has a viscosity of between 1*10{circumflex over ( )}6 mPas and 1*10{circumflex over ( )}12 mPas.

15. Cooling system according to claim 13, wherein the heat-conducting agent has a thermal conductivity between 5 W/mK and 12 W/mK, in particular in the range of 8 W/mK.

16. Cooling system according to claim 13, wherein the heat conducting agent is in direct contact with a passive heat exchanger, in particular that the heat conducting agent is clamped between the busbar and the heat exchanger.

17. Cooling system according to claim 13, wherein the batteries are enclosed in a common housing and that at least one housing wall is in direct contact with the heat conducting agent.

18. Cooling system according to claim 13, wherein the housing in the region in which its wall is in direct contact with the heat-conducting agent is formed from a metallic material.

19. Cooling system according to claim 18, wherein a fin-shaped heat sink is arranged on the housing wall which is in direct contact with the heat-conducting agent.

20. Cooling system according to claim 13, wherein a piping with a liquid or gaseous cooling medium is guided into the housing, that the piping is guided in the housing directly along the heat-conducting agent, and that the piping is guided outside the housing into an active heat exchanger.

21. Cooling system according to claim 13, wherein the first pole is a pole of a first battery module having a plurality of battery cells electrically connected in parallel, and that the second pole is a pole of a second battery module having a plurality of battery cells electrically connected in parallel.

22. Cooling system according to claim 13, wherein the heat conducting agent has an electrical conductivity of less than 10.sup.−8 S/m.

Description

[0028] In the following, the subject matter is explained in more detail with reference to a drawing showing embodiments. In the drawing show:

[0029] FIG. 1 a busbar according to an embodiment;

[0030] FIG. 2a, b cooling system according to an embodiment;

[0031] FIG. 3 a top view of a battery housing;

[0032] FIG. 4 a section through a housing cover of a battery according to an embodiment;

[0033] FIG. 5 a section through a cover of a housing of a battery according to an embodiment;

[0034] FIG. 6 a schematic view of an active cooling system according to an embodiment.

[0035] FIG. 1 shows a bus bar 2. The bus bar 2 is formed as a flat conductor with a conductive conductor core 2a and an insulation 2b surrounding the core.

[0036] It can be seen that the bus bar 2 has a rectangular conductor profile with two opposite wide surfaces, two opposite narrow surfaces, and two opposite end surfaces. The surfaces preferably extend parallel to each other, and the wide and narrow surfaces may extend parallel to each other in the longitudinal direction and the end surfaces may extend parallel to each other transversely to the longitudinal direction.

[0037] The bus bar 2 is formed by sections in which the conductor core 2a is free of the insulator 2b and sections in which the insulator 2b surrounds the conductor core 2a. Due to the insulator 2b, heat dissipation by convection at the surface of the bus bar 2 is impeded. This is particularly relevant when the bus bar 2 is used for high current applications. In this case, the conductor core 2a with its connection areas 4, 6, which are located, for example, at respective distal ends of the bus bar 2 in the area of the end faces, is freed from the insulation 2b and connected to poles of a battery, as will be shown below.

[0038] FIG. 2a shows a battery 8 with a housing 10. Battery cells 12 are arranged side by side within the housing 10. The battery cells 12 have respective terminals 14.

[0039] In a cooling system of the present invention, a busbar 2 with its connection areas 4, 6 is connected to a respective pole 14 of the battery cells 12, in particular by a material bond. In addition to the connection areas 4, 6, the busbar 2 may have further areas in which the insulator 2b is removed, this being, for example, a central connection area 5 of the busbar 2.

[0040] When the bus bar 2 conducts the currents of the battery cells 12, high currents may occur and the bus bar 2 may heat up. In order to be able to dissipate the generated joule heat, it is proposed that a heat conductive agent 16 is applied directly to the bus bar in the respective connection areas 4, 5, 6. The thermal conductive agent 16 may be gel-like or paste-like. At operating temperature, for example between −10° C. and +70° C., the heat-conducting agent 16 has a non-liquid viscosity and is thus dimensionally stable.

[0041] The thermal conductive agent 16 is applied to the conductor core 2a in the connection areas 4, 5, 6 on the surface facing away from the respective poles 14. Via the heat conducting agent 16, the Joule heat can be transported away from the bus bar 2 and, in particular, into the housing 10 or out of the housing 10.

[0042] FIG. 2b shows another embodiment of a battery 8 with a housing 10. Here, the battery 8 is formed of battery modules 20, each having at least one terminal 14. It is also possible, but not shown, that only one pole 14 of a battery module 20 is provided and the bus bar 2 is led out of the housing 10 and is connected to another electrical conductor, for example.

[0043] The bus bar 2 is connected to a connection area 6 having a pole 14 and a connection area 4 having a pole 14. It is also possible that the connection area 4 is connected to a connection of a further electrical device, a cable or the like.

[0044] On the respective opposite side of the conductor core 2a, on which the conductor core 2a is not connected to the pole 14 or the further electrical component, the heat conducting agent 16 is applied in the present case. According to FIG. 2b, the heat conducting agent 16 is in direct contact on the one hand with the conductor core 2a and on the other hand with the inner wall of the housing 10. Heat can be transported from the conductor core 2a to the housing 10 via this.

[0045] FIG. 3 shows a top view of a housing 10, in particular a housing cover. It can be seen that the shown housing wall of the housing 10 has various areas, wherein areas are provided in which a heat conducting material is embedded in the housing wall. This heat conducting material may be metallic, for example. In particular, the housing wall may be perforated by a metallic strip 22. The metallic strip 22 may extend across the width and/or length of the housing wall of the housing 10. The metallic strip 22 is in direct contact on the inner side of the housing 10 with the heat conducting material 16, which is in direct contact on the other side with the connection areas 4, 6 of the busbar 2.

[0046] The heat conducting material 16 is electrically non-conductive and forms an insulator between the pole 14 and the metallic strip 22. Via the metallic strip 22, in particular, a good heat transfer from the inside of the housing 10 to the outside of the housing 10 can take place.

[0047] As shown in FIG. 4, it is also possible for the busbar 2 to be in direct contact with the heat conducting means 16 with its connection areas 4, 6 inside the housing 10. The heat conducting means 16 is arranged on the side of the connection areas 4, 6 facing away from the poles 14. The heat conducting agent 16 is guided through the housing wall of the housing 10, for example a recess, as shown in FIG. 4. Thus, the heat conducting agent 16 is guided from the interior of the housing 10 to the exterior of the housing 10.

[0048] On the outside of the housing 10, the heat-conducting agent 16 can be applied over a large area, for example, in particular over an area that is larger than the recess in the housing wall of the housing 10 through which the heat-conducting agent 16 is guided to the outside. Good heat transfer can be achieved via this enlarged surface area.

[0049] FIG. 5 shows another embodiment in which the busbar 2 inside the housing 10 is in direct contact with the pole 14 and the heat conducting agent 16. The metallic bands 22 in the housing wall of the housing 10 connect the heat conducting agent 16 to the outside of the housing 10. On the outside of the housing 10, a heat sink 24, for example a fin-shaped heat sink 24, can be arranged directly on the metallic bands 22, via which convection is possible.

[0050] It is also possible that a so-called “heat pipe” 26 is guided inside the housing 10. The heat pipe 26 is guided into the interior of the housing 10 in a sealed manner. In the heat pipe 26 is a refrigerant which flows in flow direction 28 through the heat pipe 26. The flow direction 28 can be influenced by a motor with heat exchanger 30. At the motor/heat exchanger 30, heat is extracted from the refrigerant and released to the environment.

[0051] Inside the housing 10, the heat conduction medium 16 is provided on the busbar 2 in the connection areas 4, 6 respectively. The heat pipe 26 can be guided through the heat conduction medium 16 or directly adjacent to the heat conduction medium 26 in the housing 10. Through the refrigerant in the heat pipe 26, the heat can be transported from the heat conducting agent 16 from the inside of the housing 10 to the outside, where it can be exchanged with the environment via the heat exchanger 30.

[0052] With the aid of the solution shown, it is possible to dissipate Joule heat from bus bars used to connect battery cells or battery modules particularly effectively.

LIST OF REFERENCE SIGNS

[0053] 2 busbar

[0054] 2a conductor core

[0055] 2b insulator

[0056] 4, 5, 6 connection area

[0057] 8 battery

[0058] 10 housing

[0059] 12 battery cell

[0060] 14 battery terminal

[0061] 16 heat conductor

[0062] 20 battery module

[0063] 22 metal strip

[0064] 24 heat sink

[0065] 26 heat pipe

[0066] 28 flow direction

[0067] 30 motor/heat exchanger