NOVEL DESIGN OF A BUSBAR WITH PRE-FILLED SODIUM

Abstract

A busbar (100) comprises a first elongated structure (110A) and one or more second elongated structures (110B) made of a conductive material for transmitting an electric current. At least one section of the busbar structure has a hollow cross-section with an inner cavity (112). The inner cavity (112) is pre-filled with a cooling medium (120) to absorb the heat generated by the electric current transmitted by the busbar (100). The cooling medium (120) can be a conductive phase-change material such as sodium, which has a phase change temperature of 98 °C between solid and liquid. When the temperature of the busbar reaches 98 °C, sodium absorbs the heat without increasing the temperature of the busbar (100), thus preventing a temperature rise in the busbar (100).Since sodium is lighter, it also contributes to reducing the weight of the busbar (100) without significantly affecting the current carrying capacity.

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to the technical field of current-carrying components. In particular, it relates to a busbar capable of withstanding the heat generated when electric current is conducted through it. BACKGROUND

[0002] In the automotive sector, conventional battery packs consist of numerous individual cells connected together to achieve the required voltage and capacity for the vehicles. Within the battery pack, the individual cells are connected in series or parallel using standard busbars. These conventional busbars are elongated and made of solid materials, usually copper, which has high conductivity. They are designed to transmit electrical current between the cells and ensure efficient power delivery and distribution from the battery pack.

[0003] The design and construction of conventional busbars in high-voltage batteries presents a challenge. Due to the significantly higher electrical currents transmitted by the busbars, they tend to overheat during operation. This excessive heat, a byproduct of transmitting these very high currents, increases electrical resistance, reducing the busbar's efficiency and potentially leading to damage. Busbar overheating therefore poses a major challenge to maintaining the performance and longevity of battery packs in motor vehicles.

[0004] Conventional busbars typically use air as the cooling medium. While air cooling can offer some degree of heat dissipation, it is inefficient when it comes to generating excessive heat while simultaneously conducting high electrical currents. Furthermore, using air as a cooling medium necessitates the integration of additional mechanisms, such as fans or ducts, to improve airflow and cooling efficiency.

[0005] DE102011118686A1 discloses a solution to mitigate the aforementioned problem by providing a busbar with an internal channel for circulating a coolant that evaporates upon absorbing heat within the internal channel. The busbar also includes a cooling circuit connected to a heat exchanger to facilitate the circulation of the coolant within the busbar's internal channel. However, the solution described in the cited reference may not be cost-effective or efficient, as it requires the use of additional equipment to cool the heated busbar, which in turn requires a certain amount of energy for coolant circulation. The use of additional equipment can not only increase energy consumption but also the cost of the busbar and the space required within it, potentially impacting its design and performance.

[0006] Therefore, in engineering there is a need to mitigate the aforementioned problem of heat dissipation, which necessitates the development of a novel busbar capable of withstanding the heat generated during the transmission of electric current without the use of an external heat dissipation device. OBJECTIVES OF THE PRESENT DISCLOSURE

[0007] A general objective of the present disclosure is to overcome the disadvantages of known busbars and to provide an efficient busbar.

[0008] One objective of the present disclosure is to provide a busbar that does not heat up to high temperatures due to the heat generated when conducting higher electrical currents, without the need for an additional heat dissipation mechanism.

[0009] Another purpose of the present disclosure is to provide a cooling mechanism for the busbar and thereby prevent the busbar from heating up to high temperatures.

[0010] Another objective of the present disclosure is to provide a busbar that has a lower weight without compromising its current-carrying capacity.

[0011] Another purpose of the present disclosure is to provide a busbar that replaces expensive materials with cheaper materials. SUMMARY

[0012] Aspects of the present disclosure relate to current-carrying components. In particular, the present disclosure relates to a busbar capable of withstanding the heat generated when electric current is conducted through it.

[0013] According to one aspect, the proposed busbar comprises at least one elongated structure. This at least one elongated structure consists of a conductive material for transmitting an electric current. At least one section of the elongated structure has a hollow cross-section with an internal cavity. The internal cavity is pre-filled with a cooling medium that absorbs the heat generated by the electric current transmitted by the busbar.

[0014] In one embodiment, the cooling medium can be a conductor for electric current.

[0015] In one embodiment, the cooling medium can be a phase change material.

[0016] In one embodiment, the phase change material can be a phase change material that changes phase at a temperature below the upper temperature limit of the busbar.

[0017] In one embodiment, the phase change material can be selected from a material that changes its phase in a temperature range of 95 degrees Celsius to 100 degrees Celsius.

[0018] In one embodiment, the cooling medium can be sodium metal, which has a phase change temperature of 98 degrees Celsius.

[0019] In one embodiment, the cooling medium can be pre-filled into the inner cavity. The cooling medium can be in a solid state during pre-filling.

[0020] In one embodiment, the inner cavity can extend over the entire length of the elongated structure.

[0021] In one embodiment, the at least one elongated structure can comprise a first elongated structure and one or more second elongated structures. The first elongated structure and the one or more second elongated structures can be arranged at an angle to the first elongated structure as branches.

[0022] In one embodiment, each of the first elongated structure and each of the one or more second elongated structures can contain the inner cavity. The inner cavities of the first elongated structure and the one or more second elongated structures can be interconnected.

[0023] Various objects, features, aspects and advantages of the invention will become clearer from the following detailed description of preferred embodiments together with the accompanying drawings, in which the same numbers represent the same components. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings serve to further understand the present disclosure and are an integral part of this description. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams serve only for illustration and thus do not constitute a limitation of the present disclosure. Fig. Figure 1 shows an exemplary schematic view of a busbar according to the embodiments of the present disclosure. Fig. Figure 2 shows an exemplary cross-sectional view of the proposed busbar in accordance with the embodiments of the present disclosure. DETAILED DESCRIPTION

[0025] A detailed description of the embodiments of the disclosure illustrated in the accompanying drawings follows. The embodiments are described in sufficient detail to clearly convey the disclosure. However, the intention is not to limit foreseeable variations of the embodiments with the necessary level of detail; rather, the aim is to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the present disclosure as defined by the accompanying claims.

[0026] The explanations given here refer to a busbar that is able to withstand the heat generated when electric current is conducted through it.

[0027] According to one definition, a busbar comprises an elongated structure made of a conductive material. This structure has a cavity running along its entire length, along its horizontal axis. Furthermore, the structure is pre-filled with a cooling medium capable of conducting electricity. This cooling medium is contained within the cavity, which extends the full length of the structure. As the structure heats up during the conduction or transmission of electricity, it is cooled by the pre-filled cooling medium without the need for additional cooling mechanisms.

[0028] Furthermore, the pre-filled cooling medium conducts the electric current through it and accordingly absorbs the heat generated as a byproduct by the elongated structure during the conduction of the electric current. The pre-filled cooling medium is in a liquid state during the pre-filling process, so that the liquid cooling medium solidifies after being enclosed within the elongated structure. Moreover, the pre-filled cooling medium is designed to change its phase, or medium, from solid to liquid within a specific temperature range when absorbing heat from the heated elongated structure, thereby increasing the thermal efficiency of the elongated structure.

[0029] With reference to the Fig. 1 and Fig.2. A busbar (hereinafter referred to as "busbar 100") is described which is able to withstand the heat generated during the transmission of a high electric current through the busbar. The proposed busbar 100 can contain a cooling medium 120 prefilled in at least one elongated structure 110, thereby enabling the busbar 100 to withstand heat while electric current flows through it.

[0030] In one embodiment, the at least one elongated structure 110 can be made of a conductive material, such as copper or aluminum, and have a hollow cross-section with an internal recess 112. In one embodiment, the internal recess 112 can extend over the entire length of the elongated structure 110 or be limited to certain sections of the elongated structure. Furthermore, the at least one elongated structure 110 can comprise a first elongated structure 110A and one or more second elongated structures, such as the second elongated structures 110B-1 and 110B-2 (here collectively and individually referred to as second elongated structures / structure 110B), which are arranged as branches at an angle to the first elongated structure 110A.For example, one or more of the second elongated structures 110B can be arranged perpendicular to the first elongated structure 110A, but all other angles between the first elongated structure and the second elongated structures are possible without any restrictions within the scope of this disclosure. Furthermore, each of the first elongated structure 110A and the second elongated structures 110B can have internal recesses, such asthe inner recesses 112A in the first elongated structure 110A and the inner recesses 112B-1 and 112B-2 in the second elongated structures 110B (here collectively referred to as recess 112), so that a first inner recess 112A-1 of the first elongated structure 110A and one or more second inner recesses 112B-1, 112B-2 of the one or more elongated structures 110B-1, 110B-2 can be connected to each other, thereby enabling free heat transfer within the cooling media 120 of the busbar 100.

[0031] In one embodiment, the inner recess 112 is pre-filled with the cooling medium 120, which changes its phase when heated. The phase change of the cooling medium 120 can lead to higher heat absorption without increasing the temperature of the busbar 100.

[0032] In one embodiment, the cooling medium 120 can be in a liquid state while being pre-filled into the inner recess 112 and can solidify at room temperature. Furthermore, the cooling medium 120 can consist of a metal that has good thermal conductivity, so that replacing part of the section of the busbar 100 with the cooling medium 120 does not impair the current-carrying capacity of the busbar 100.

[0033] In one embodiment, the present disclosure provides a busbar 100 that uses sodium as a cooling medium 120. The pre-filled sodium absorbs heat from the busbar and changes its phase from solid to liquid at a certain threshold (e.g., 98°C). This increases its thermal conductivity and ensures more efficient cooling of the busbar. In this way, the temperature of the busbar 100 is maintained by absorbing the heat generated by the transmitted electric current. Sodium also has relatively good conductivity. Therefore, reducing the cross-sectional area of ​​the busbar 100's base material by replacing it with sodium does not significantly affect the busbar's current-carrying capacity. Furthermore, sodium has a lower density than copper, which makes the busbar lighter.Furthermore, sodium is cheaper, so the busbar 100 with a sodium-filled inner recess is cost-effective.

[0034] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention can be developed without deviating from the fundamental scope of the invention. The scope of the invention is defined by the following claims. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person with ordinary technical knowledge to manufacture and use the invention when combined with information and knowledge available to such a person. ADVANTAGES OF THE INVENTION

[0035] The present disclosure offers a busbar that overcomes the disadvantages of conventional busbars and is more efficient and cost-effective.

[0036] The present disclosure provides a busbar which does not heat up to high temperatures due to the heat generated when electric current is passed through it, without the need for an additional heat dissipation mechanism.

[0037] The present disclosure provides a busbar that has a higher heat absorption capacity and thereby prevents the busbar from heating up to high temperatures.

[0038] The present disclosure provides a busbar that is lighter without compromising its current-carrying capacity.

[0039] The present disclosure offers a power rail that replaces expensive materials with cheaper materials. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102011118686A1

[0005]

Claims

[1] Busbar (100) comprising the following: at least one elongated structure (110) made of a conductive material for carrying an electric current, wherein at least one section of the elongated structure has a hollow cross-section with an inner recess (112), wherein the inner recess (112) is pre-filled with a cooling medium (120) to absorb heat generated due to the electric current carried by the busbar (100). [2] Busbar (100) according to claim 1, wherein the cooling medium (120) is an electrical conductor. [3] Busbar (100) according to claim 1, wherein the cooling medium (120) is a phase change material. [4] Busbar (100) according to claim 3, wherein the phase change material is selected such that the phase change of the phase change material takes place at a temperature which is lower than an upper temperature limit of the busbar (100). [5] Busbar (100) according to claim 3, wherein the cooling medium (120) is sodium. [6] Busbar (100) according to claim 3, wherein the cooling medium (120) is prefilled in liquid form in the inner recess (112). [7] Busbar (100) according to claim 1, wherein the inner recess (112) extends over the entire length of the elongated structure (110). [8] Busbar (100) according to claim 3, wherein the phase change material is selected such that the phase change of the phase change material takes place at a temperature in the range of 95 degrees Celsius to 100 degrees Celsius. [9] Busbar (100) according to claim 1, wherein the at least one elongated structure (110) comprises a first elongated structure (110A) and one or more second elongated structures (110B) arranged as branches at an angle to the first elongated structure (110A). [10] Busbar (100) according to claim 9, wherein each of the first elongated structure (110A) and one or more second elongated structures (110B) comprises the inner recess (112) and wherein the inner recesses (112) are connected to each other.

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