Bus bar assembly

Abstract

A battery system (10) comprising at least one battery cell (12, 14) and a bus bar assembly (16); a bus bar assembly (16) for an electric vehicle having a bus bar (18) for power distribution and a connector (20) wherein the bus bar (18) comprises a body made of an electrically conductive material, the body being at least partially hollow such that the bus bar (18) comprises at least one electrically conductive inner surface (22) and an air gap adapted to increase cooling efficiency by natural convection, therefore, passive cooling is realized.

Description

Technical Field

[0001] The invention relates to a busbar assembly for power distribution in an electric vehicle. The field of the invention is more particularly that of hybrid or electric vehicles, in which the energy is stored in batteries. Background Art

[0002] Busbars are metal strips or bands that conduct electricity and are used in the distribution of electricity. Power distribution equipment, including switchboards, switchgear, and motor control centers, use busbar conductors to connect circuit breakers and other protective devices to the loads.

[0003] Automotive battery cells can be connected using busbars to make, for example, battery modules and battery packs. Power sources for electric vehicles such as hybrid vehicles or electric vehicles require large power outputs. The current flowing into and out of a single cell (i.e., a single electrochemical cell) allows the current or voltage to be increased to produce the desired power output when several such cells are combined into successively larger assemblies (such as modules and groups). In this article, the assemblies of larger modules and groups are composed of one or more connected cells in series (for increasing voltage), in parallel (for increasing battery capacity), or both, and may include additional structures to ensure the correct installation and operation of these units. In this type of power supply device, battery cells arranged adjacent to each other are electrically connected to each other by busbars each made of a conductive material.

[0004] In a known manner, in a power supply device in which battery cells are electrically connected to each other via a bus bar assembly, bus bars made of a conductive material are stacked on electrode terminals (or electrode leads) of the battery cells via connectors, and the stacked portions of the bus bars are welded to the electrode terminals of the battery cells. With this configuration, the battery cells can be connected to each other with a small resistance. However, an increase in the number of cells additionally increases the risk of overheating of the battery due to the heat generated by the cells.

[0005] It is therefore important for the busbar to have a structure which, on the one hand, ensures the rigidity required to withstand the electrodynamic stresses generated by the current flow during normal conduction and, on the other hand, allows an optimized heat flow.

[0006] Busbar assemblies comprising busbars having different shapes are known from the prior art.

[0007] For example, document EP2324545A1 discloses a bus system used in power distribution equipment. The bus system includes a bus bar, which includes a pair of bowl-shaped conductors facing oppositely, forming an octagonal cross section, and an air gap is formed in the cross section. The air gap improves cooling efficiency by exposing a larger surface area of ​​the conductor directly to natural convection obtained by airflow.

[0008] EP1131868A1 discloses a busbar having a C-shaped cross section. The C-shaped cross section allows a modular geometry.

[0009] However, this arrangement does not allow dealing with the thermal management of the busbars without degrading the performance of such busbars.

[0010] EP2626946A1 discloses a bus bar module having a bus bar and a cover member with an active cooling system. The bus bar module 1 is connected to a battery pack 9 cooled by forced air cooling. A first air outlet hole defining an air gap is formed on the bus bar, and a second air outlet hole is formed on the cover member. The first air outlet hole 11 and the second air outlet hole 73 form an air flow path in each bus bar housing portion that connects from the upstream side to the downstream side along a predetermined air cooling direction. Forced air cooling consumes battery power and introduces a failure point in the form of a fan motor. Summary of the invention

[0011] The present disclosure aims to solve the above-mentioned problems. Therefore, the present invention provides a busbar assembly for an electric vehicle according to claim 1. The busbar assembly has a busbar and a connector for power distribution. The busbar includes a body made of a conductive material, which is at least partially hollow, so that the busbar includes at least one conductive inner surface and an air gap suitable for improving cooling efficiency by natural convection. Therefore, only a passive cooling system is used. The connector is arranged on the conductive inner surface of the busbar and / or connected to the conductive inner surface of the busbar, and the outer surface of the busbar is electrically insulated.

[0012] This design allows the busbar to be reduced in size without sacrificing performance. Due to natural convection, active cooling is not required, thus avoiding the disadvantages of active cooling systems. Instead, the contact area is on the inner surface of the busbar body, increasing the conductive surface. In addition, the hollow construction increases the heat transfer to the environment. The amount of material used in production is reduced, resulting in economic benefits and lighter components. Finally, since the connection is made inside the busbar, the busbar remains touch-safe on its outer surface and suitable for maintaining electrical insulation even in the event of a fire.

[0013] In one embodiment, the body extends longitudinally between a first end and a second end along a longitudinal axis X, and the body has a body length L, wherein the body includes a cavity extending longitudinally through the body from the first end to the second end. Thus, the cavity passes through the body, increasing the conduction surface and the air gap for natural convection.

[0014] In one embodiment, the body is unitary.The body is made from one part and has no joints formed.

[0015] In one embodiment, the sleeve is an outer sleeve and the body further comprises an inner sleeve. Thus, the natural cooling surface of the busbar is increased, thereby improving the cooling performance. In addition, for the same current, less material is required.

[0016] In one embodiment, the cavity has a substantially circular or quadrilateral or triangular cross-section.

[0017] In one embodiment, the body includes lateral holes connected to the cavity. The lateral holes increase natural air convection. Air can flow freely between the air gaps without being trapped in the cavity. The lateral holes allow natural convection of air in the cavity.

[0018] In one embodiment, the lateral aperture extends longitudinally over a portion of the body length L. In another embodiment, the lateral aperture is formed by a plurality of apertures. However, in other embodiments, the lateral aperture may have other shapes.

[0019] In one embodiment, the cavity is a first cavity and the body comprises a second cavity. This increases the connection surface without increasing the length of the busbar body. Furthermore, the two air gaps are thus arranged to increase natural convection by exposing more surface area of ​​the conductor directly to the air flow. The two air gaps are for example connected to each other.

[0020] In one embodiment, the second cavity extends longitudinally through the body from the first end to the second end. The first cavity and the second cavity may each have an annular cross-section. For example, the first cavity and the second cavity may be arranged concentrically around the longitudinal axis.

[0021] In one embodiment, the body has a substantially circular or quadrilateral or triangular cross section. These shapes allow easy manufacture of an integral body (one-piece body and no joints) with a cavity.

[0022] The invention also relates to a battery system comprising at least one battery cell and a bus bar assembly according to any one of the preceding claims, wherein a connector connects an electrode lead of at least one battery cell to a bus bar body. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention and its advantages will be better understood by reading the following description, which is given by way of example only and with reference to the accompanying drawings, in which:

[0024] Figure 1 schematically illustrating a first bus bar assembly and a second bus bar assembly connecting a first battery component and a second battery component;

[0025] Figure 2A and Figure 2BA schematic perspective view and a cross-sectional view showing a bus bar assembly according to a first embodiment of the present invention;

[0026] Figure 3A and Figure 3B shows a schematic perspective view and a cross-sectional view of a bus bar assembly according to a second embodiment of the present invention;

[0027] Figure 4A and Figure 4B A schematic perspective view and a cross-sectional view showing a bus bar assembly according to a third embodiment of the present invention;

[0028] Figure 5A and Figure 5B A schematic perspective view and a cross-sectional view showing a bus bar assembly according to a fourth embodiment of the present invention;

[0029] Fig. 6A and Figure 6B A schematic perspective view and a cross-sectional view showing a bus bar assembly according to a fifth embodiment of the present invention;

[0030] Figure 7 shows a schematic perspective view of a bus bar assembly according to a sixth embodiment of the present invention;

[0031] Fig. 8A , Figure 8B and Figure 8C Cross-sectional views of three different bus bar assemblies according to seventh, eighth and ninth embodiments of the present invention are shown. DETAILED DESCRIPTION

[0032] Embodiments of the present disclosure will be best understood by reference to the accompanying drawings, in which like reference numerals represent like or similar elements. It will be readily appreciated that, as shown in the general description herein and in the accompanying drawings, the components of the disclosed embodiments may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of embodiments of the systems and methods of the present disclosure is not intended to limit the scope of the present disclosure as claimed, but is merely representative of possible embodiments of the present disclosure.

[0033] Figure 1 A portion of an exemplary battery system 10 is shown. The battery system 10 includes a first battery component 12 and a second battery component 14. As shown, the first and second battery components 12, 14 are connected in parallel. However, in other embodiments, several battery components connected in parallel or in series or in parallel and in series may be provided. A bus bar assembly 16 is used to connect the battery components arranged in parallel. Figure 1 1 , first and second bus bar assemblies 16 are depicted. Each bus bar assembly 16 is coupled to first and second battery components 12, 14. The first and second battery components 12, 14 may be battery cells, battery modules, battery packs, or any battery subassembly.

[0034] FIG. 2A to FIG. 8C Ten different embodiments of a busbar assembly 16 according to the present invention are shown. The busbar assembly 16 according to the present invention comprises a busbar 18 for power distribution, and a connector 20. The connector electrically connects the busbar 18 to the first and second battery components 12, 14. The busbar 18 comprises a body made of a conductive material. The body extends longitudinally along a longitudinal axis X and has a body length L. The body is at least partially hollow and comprises an inner surface 22 and an outer surface 24. The hollow portion of the busbar body forms at least one air gap. The air gap allows to improve the cooling efficiency of the busbar 18 and thus the busbar assembly 16 by natural convection. Thus, the air gap allows passive cooling without the need for active cooling. The air gap forms part of a passive cooling arrangement. The hollow portion is formed, for example, by a cavity 26. The inner surface 22 faces the cavity 26. The inner surface 22 delimits the cavity 26. The inner surface 22 is, for example, not painted or coated and is therefore a conductive surface. The outer surface 24 may be painted or coated or treated, or may be provided with an additional layer to electrically insulate the surface. A lateral hole 28 is provided between the inner surface 22 and the outer surface 24. As described below, the lateral hole 28 may have different shapes. The connector 20 is at least partially arranged on the inner surface 22 of the busbar body. This allows a compact busbar assembly and good electrical conductivity to be provided. The busbar body may be integral. In other words, the busbar body may be formed from a unique component and does not include any cutouts or joints. The body is, for example, a molded body or an extruded part. There is material continuity.

[0035] The cavity 26 may have different shapes or cross-sections, such as Figure 2A As is apparent in FIG. 9C , the busbar 18 may have different cross-sectional shapes, such as Figure 2A As seen in Figure 9C.

[0036] For example, in Figure 2A and Figure 2B In the first embodiment shown, the busbar 18 has a cylindrical form with a circular cross section. More specifically, the busbar body has an annular cross section. The cavity 26 passes through the entire length L of the body (in another variant of the invention, the cavity can be a blind hole, the cavity length of the blind hole is less than the length of the body). The lateral holes 28 are formed by a plurality of holes arranged on the busbar body near the first free end 30 and / or the second free end 32. For example, three holes are provided at one end and another three holes are provided at the other end.

[0037] Figure 3A and Figure 3BA second embodiment of a busbar assembly 16 is shown, which has a busbar body with a circular cross section. The cavity 26 has an annular cross section so that the body includes a core 181 and an outer sleeve 182, and the cavity 26 extends between the core and the outer sleeve. The core 181 is connected to the outer sleeve 182, for example, at some connection points C1, C2 along the longitudinal axis X. The core 181 is cylindrical, and the outer sleeve 182 has an annular cross section. The core and the outer sleeve can be integral. For example, the core and the outer sleeve form an extruded component.

[0038] Figure 4A and Figure 4B The third embodiment shown has a body including a core 181 and an outer sleeve 182. The core 181 and the outer sleeve 182 each have a rectangular cross section. The cavity 26 also has a rectangular cross section. The cavity 26 extends between the outer sleeve 181 and the sleeve 182. The lateral hole 28 is formed by a longitudinal slit arranged on the busbar body. The core 181 is connected to the outer sleeve 182, for example, at some connection points C1, C2 along the longitudinal axis. The core and the outer sleeve can be integral. For example, the core and the outer sleeve form an extruded component.

[0039] exist Figure 5A , Figure 5B , Fig. 6A and Figure 6B In the figure, the cross section of the body is triangular. Figure 5A and Figure 5B The fourth embodiment in the present invention shows a hollow body, wherein Fig. 6A and Figure 6B In the fifth embodiment of the present invention, the main body comprises a core 181 and a sleeve 182. Both have a triangular cross section, and the cavity 26 extends between the core 181 and the sleeve 182. The lateral hole 28 is formed by a longitudinal slit arranged on the busbar body. The lateral hole 28 extends longitudinally only over a portion of the main body length L. The core 181 is connected to the outer sleeve 182, for example, at some connection points C1, C2 along the longitudinal axis X. The core and the outer sleeve can be integral. For example, the core and the outer sleeve form an extruded component (only one main body).

[0040] Figure 7 A sixth embodiment is shown, which is clearly similar to Figure 3A 181 and the outer sleeve 182. The embodiment of the present invention is shown in Figure 182, but between the core 181 and the outer sleeve 182, the body also includes an inner sleeve 183. Therefore, the cavity 26 can have two parts (or in other words, there may be two cavities 261, 262). The first part (or the first cavity 261) extends between the core 181 and the inner sleeve 183, and the second part (or the second cavity 262) extends between the inner sleeve 183 and the outer sleeve 182. The first part and the second part are each obviously annular. The inner sleeve can be connected to the outer sleeve and the core at some connection points.

[0041] Fig. 8A A cross-sectional view of a seventh embodiment is shown, similar to Figure 4A and Figure 4B The third embodiment of the present invention, and wherein the body (and therefore the outer sleeve 182) has a square cross section. As shown, the core 181 has a rectangular cross section, but in a variant, the core 181 may also have a square cross section.

[0042] Figure 8B The eighth embodiment disclosed in includes a hollow body having a square cross section. The ninth embodiment includes a hollow body having a rectangular cross section.

[0043] In the second, third, fifth, sixth and seventh embodiments, the presence of the core 181 allows to further increase the conductive surface, thereby improving the performance of the busbar assembly 16. However, such a core 181 also increases the amount of material and therefore the weight. On the other hand, a completely hollow body (as shown in the first, fourth, eighth and ninth embodiments) allows to increase the air gap and improve the cooling efficiency by natural convection of the busbar assembly. Thus, passive cooling is achieved and the weight and size of the assembly can be significantly limited.

[0044] The bus bar assembly described above can be used for Figure 1 In the illustrated battery system 10 , a bus bar 18 is connected to at least a first battery component via a connector 20 .

[0045] Reference numerals

[0046] Battery System 10

[0047] First battery component 12

[0048] Second battery component 14

[0049] Bus bar assembly 16

[0050] Busbar 18

[0051] Main body length L

[0052] Longitudinal axis X

[0053] Connector 20

[0054] Inner surface 22

[0055] Outer surface 24

[0056] Cavity 26

[0057] Side hole 28

[0058] The first free end 30 and / or the second free end 32

[0059] Core 181

[0060] Outer sleeve 182

[0061] Inner sleeve 183

[0062] First cavity 261

[0063] Second cavity 262

[0064] Connecting points C2 C1

Claims

1. A bus bar assembly (16) for an electric vehicle having a bus bar (18) for power distribution, a connector (20) and a passive cooling arrangement, wherein: The bus bar (18) comprises a body made of an electrically conductive material, the body being at least partially hollow, such that the bus bar (18) comprises at least one electrically conductive inner surface (22) and an air gap adapted to enhance cooling efficiency by natural convection, Features The passive cooling arrangement is at least partially formed by the air gap, and the connector (20) is arranged on and / or connected to the inner surface (22) of the bus bar (18), and the outer surface (24) of the bus bar is electrically insulating.

2. The bus bar assembly (16) according to claim 1, wherein: The body extends longitudinally along a longitudinal axis (X) between a first end and a second end and has a body length L, wherein the body includes a cavity (26) extending longitudinally through the body from the first end to the second end.

3. The bus bar assembly (16) according to claim 2, wherein: The cavity (26) has a substantially circular, quadrilateral or triangular cross section.

4. The busbar assembly (16) according to claim 2 or claim 3, wherein: The body includes a lateral hole (28) connected to the cavity (26).

5. The busbar assembly (16) according to any one of claims 2 to 4, wherein: The lateral aperture (28) extends longitudinally over a portion of the length L of the body.

6. The busbar assembly (16) according to any one of claims 2 to 4, wherein: The lateral hole (28) is formed by a plurality of holes.

7. The busbar assembly (16) according to any one of claims 2 to 6, wherein: The cavity (26) is a first cavity (26), and the body includes a second cavity (26).

8. The bus bar assembly (16) according to claim 7, wherein: The second cavity (26) extends longitudinally through the body from the first end (30) to the second end (32).

9. The busbar assembly (16) according to any one of claims 1 to 8, wherein: The body includes a core (181) and a sleeve (182).

10. The bus bar assembly (16) according to claim 9, wherein: The sleeve is an outer sleeve (182), and wherein the body further comprises an inner sleeve (183).

11. The busbar assembly (16) according to any one of claims 1 to 9, wherein: The body is unitary.

12. The busbar assembly (16) according to any one of claims 1 to 9, wherein: The body has a generally circular cross-section.

13. The busbar assembly (16) according to any one of claims 1 to 9, wherein: The body has a generally quadrilateral cross-section.

14. The busbar assembly (16) according to any one of claims 1 to 9, wherein: The body has a generally triangular cross-section.

15. A battery system (10) comprising at least one battery component (12, 14) and a busbar assembly (16) according to any one of the preceding claims, wherein: The connector (20) connects the battery component to the bus bar (18).

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