Electrical Vehicle Charging System for Charging an Electrical Vehicle

Abstract

A system and method for a liquid cooled cable arrangement for high-power fast charging of electric vehicles includes a charging connector and a liquid cooled charging cable. The cable comprises several insulated positive and negative conductors for supplying charging current, an inner fluid channel and an outer fluid channel surrounding the inner fluid channel. The positive and negative conductors are arranged within the inner fluid channel. The charging connector includes at least a positive contact electrically connected to the positive conductors by a first connecting element, and a negative contact electrically connected to the negative conductors by a second connecting element. The first and second connecting elements include a thermally conductive and electrically conductive material and are electrically isolated from each other. The first and second connecting elements are thermally connected to the inner and outer fluid channels.

Claims

1. A liquid cooled cable arrangement for high-power fast charging of electric vehicles, comprising: a charging connector and a liquid cooled charging cable, wherein the liquid cooled charging cable comprises several insulated positive conductors and several insulated negative conductors for supplying charging current, an inner fluid channel, and an outer fluid channel surrounding the inner fluid channel, the inner fluid channel and the outer fluid channel together providing a supply path and a return path for liquid coolant; wherein the positive conductors and the negative conductors are arranged within the inner fluid channel; wherein the charging connector comprises at least a positive contact electrically connected to the positive conductors by a first connecting element and a negative contact electrically connected to the negative conductor by a second connecting element; wherein the first connecting element and the second connecting element each includes a thermally conductive and electrically conductive material, the first and second connecting elements being electrically isolated from each other; wherein the first connecting element and the second connecting element each is thermally connected to the inner channel and to the outer channel of the charging cable such that heat generated in the contacts during charging can be removed by the liquid coolant.

2. The liquid cooled cable arrangement of claim 1, wherein the first connecting element and the second connecting element each comprises fluid channels fluidly connecting the inner fluid channel and the outer fluid channel of the charging cable such that heat generated in the contacts during charging can be removed by the liquid coolant.

3. The liquid cooled cable arrangement of claim 1, wherein the first connecting element and the second connecting element each includes a charging cable mating part for connection with the charging cable, and a contact mating part for connection with the respective contact, wherein the contact mating part has a wider radial extension than the charging cable mating part.

4. The liquid cooled cable arrangement of claim 1, wherein the fluid channels in at least one of the first connecting element and the second connecting element includes an axial channel part and a radial channel part, wherein the axial channel part is open towards an axial surface of the connecting element, the radial channel part is open towards a radial surface of the connecting element and the axial channel part and the radial channel part are fluidly connected to each other.

5. The liquid cooled cable arrangement of claim 1, further comprising an insulating casing that houses the first connecting element and the second connecting element, the insulating casing disposed to electrically insulate said connecting elements from each other.

6. The liquid cooled cable arrangement of claim 5, wherein the insulating casing is disposed to house the positive contact and the negative contact and electrically insulates said contacts from each other.

7. The liquid cooled cable arrangement of claim 5, wherein the insulating casing is disposed to provide a connector housing insulating the connector from a surrounding environment.

8. The liquid cooled cable arrangement of claim 5, wherein a gap is formed between the insulating casing and each connecting element, which gap forms a fluid channel fluidly connecting the radial channel parts with the outer fluid channel of the charging cable.

9. The liquid cooled cable arrangement of claim 5, wherein the insulating casing is injection molded.

10. The liquid cooled cable arrangement of claim 1, wherein the liquid coolant is a dielectric fluid.

11. The liquid cooled cable arrangement of claim 1, wherein the first plurality of positive conductors and the second plurality of negative conductors are crimped and/or welded or soldered to a respective connecting element.

12. The liquid cooled cable arrangement of claim 1, wherein the contacts are connected to a respective connecting element by a push-in mechanism, by screwing and/or by welding or soldering or brazing and/or by gluing.

13. The liquid cooled cable arrangement of claim 1, wherein the contacts comprise at least one of pockets for thermocouples, pockets for contact springs close to tips of the contacts, stress relief openings at joints between different contacts, and cooling channels connected to the fluid channels.

14. A method for liquid cooling a charging connector connected to a liquid cooled charging cable for high-power fast charging of electric vehicles, comprising: providing the liquid cooled charging cable, the liquid cooled charging cable comprising: several insulated positive conductors and several insulated negative conductors for supplying charging current and an inner fluid channel and an outer fluid channel surrounding the inner fluid channel, the inner fluid channel and the outer fluid channel together providing a supply path and a return path for liquid coolant; wherein the positive conductors and the negative conductors are arranged within the inner fluid channel; wherein the charging connector comprises at least a positive contact electrically connected to the positive conductors by a first connecting element and a negative contact electrically connected to the negative conductors by a second connecting element; wherein the first connecting element and the second connecting element each includes a thermally conductive and electrically conductive material and are electrically isolated from each other; wherein the first connecting element and the second connecting element each is thermally connected to the inner channel and to the outer channel of the charging cable; and conveying liquid coolant through the inner fluid channel, the connecting elements and the outer fluid channel for removing heat generated during charging in the contacts.

15. The method of claim 14, wherein the first connecting element and the second connecting element each comprises fluid channels fluidly connecting the inner fluid channel and the outer fluid channel of the charging cable; and wherein the method further includes conveying liquid coolant through the fluid channels of the first connecting element and the second connecting element for removing heat generated during charging in the contacts.

16. The method of claim 14, wherein the liquid cooled charging cable includes an insulating casing, wherein a gap is formed between the insulating casing and each connecting element, and wherein the method further includes conveying liquid coolant through the gap for removing heat generated during charging in the contacts.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0041] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0042] FIG. 1 shows a sectional view through a liquid cooled charging cable in a direction orthogonal to the longitudinal axis of the cable.

[0043] FIGS. 2A, 2B and 2C show an embodiment of a charging connector according to the invention in a sectional view taken along the longitudinal axis of the charging cable from different perspectives.

[0044] FIG. 3 shows the sectional view of FIG. 2A, wherein the flow of cooling fluid is indicated in the drawing.

[0045] FIG. 4 shows a partially cut perspective view of an embodiment of a charging connector according to the invention.

[0046] FIG. 5 shows the charging connector of FIG. 4 from a different point of view.

DETAILED DESCRIPTION OF THE INVENTION

[0047] The present disclosure describes a system and method comprising a charging connector and a liquid cooled charging cable, wherein the liquid cooled charging cable comprises several insulated positive conductors and several insulated negative conductors for supplying charging current and an inner fluid channel and an outer fluid channel surrounding the inner fluid channel, the inner fluid channel and the outer fluid channel together providing a supply path and a return path for liquid coolant, wherein the positive conductors and the negative conductors are arranged within the inner fluid channel.

[0048] FIGS. 2A-2C show a part of a liquid cooled cable arrangement according to a preferred implementation in a schematic sectional view along the longitudinal axis for high-power fast charging of electric vehicles. The arrangement comprises a charging connector 1 and a liquid cooled charging cable 2. FIG. 1 shows a sectional view through the liquid cooled charging cable 2 in a direction orthogonal to the longitudinal axis of the cable 2. The liquid cooled charging cable 2 comprises three positive conductors 3 and three negative conductors 4 for supplying charging current. It further comprises an insulated ground line 5, which is arranged in the middle of the section of the charging cable 2. The positive conductors 3, the negative conductors 4 and the ground line 5 are each individually insulated to prevent mutual contact.

[0049] The charging cable further comprises an inner fluid channel 6 and an outer fluid channel 7 surrounding the inner fluid channel 6. The inner fluid channel 6 and the outer fluid channel 7 together provide a supply path 8 and a return path 9 for a liquid coolant. The inner fluid channel 6 is enclosed by a tight sheath 10, which at the same time divides the inner fluid channel 6 from the outer fluid channel 7. The outer fluid channel 7 again is enclosed by an outer sheath 11 surrounding the entire cable 2. The three positive conductors 3, the three negative conductors 4 and the ground line 5 are each arranged within the inner fluid channel 6. The ground line 5 connection is not dealt with in detailed in this disclosure, as the charging cable 2 fits to a standardized connector layout.

[0050] The charging connector 1 comprises a positive contact 12, a first connecting element 13, a negative contact 14 and a second connecting element 15 for connecting to respective socket of an electric vehicle, not shown. The positive contact 12 is electrically connected to the positive conductors 3 by the first connecting element 13. The negative contact 14 is electrically connected to the negative conductors 4 by the second connecting element 15. The first connecting element 13 and the second connecting element 15 each are copper blocks. The connection between the positive conductors 3/negative conductors 4 and the first connecting element 13/second connecting element 15 needs to be reliable, but does not present high electric insulation requirements since the conductors 3, 4 insulation prevents electrical contact of the positive and the negative conductors 3, 4. Since at the respective connection to the copper blocks of the first connecting element 13 and the second connecting element 15, respectively, the conductors 3,4 position is fixed, touching of the conductors 3, 4 is prevented in the area. The space for connection (e.g. soldered) can be formed inside of the copper blocks of the first connecting element 13 and the second connecting element 15 themselves.

[0051] The first connecting element 13 and the second connecting element 15 each are embodied/arranged in an electrically insulating casing 16. The insulating casing 16 prevents accessibility of the live parts, i.e. to those parts energized during charging, from outside. Further, the insulating casing 16 provides an insulating separation of the first connecting element 13 and the second connecting element 15 by an insulating wall 17 arranged in between. This separation, i.e. the creep-age distance between the first and the second connecting elements 13, 15 advantageously is as large as possible.

[0052] The first connecting element 13 and the second connecting element 15 are identically formed, such that the following description of the first connecting element 13 also is applicable to the second connecting element 15. The first connecting element 13 consist of a charging cable mating part 18 for connection with the charging cable 2 and a contact mating part 19 for connection with the concerning contact 12, 14. This may, in principle, be achieved also by having connecting element 13 and 12 made from one solid element. Contacts 12 may also be replace-able, in which case they are two different parts. It further comprises fluid channels 20, which fluidly connect the inner fluid channel 6 and the outer fluid channel 7 of the charging cable 2. Each fluid channel 20 comprises an axial channel part 21 and a radial channel part 22. Each axial channel part 21 is open towards an axial surface 23 of the connecting element 13 located at its charging cable mating part 18. Further, each radial channel part 22 is open towards a radial surface 24 of the connecting element 13 located at its contact mating part 19. The axial channel part 21 and the radial channel part 22 of each fluid channel 20 are fluidly connected to each other. By this way, there is provided a flow path for coolant liquid, which is described later.

[0053] The charging cable mating part 18 and the contact mating part 19 each are formed essentially as half-cylinders, wherein the contact mating part 19 has a wider radial extension than the charging cable mating part 18. Therefore, there is a large contact area between the concerning contact 12, 14 and the contact mating part 19, such that a very effective heat transfer from the contact 12, 14 to the connecting element 13 can be established. The insulating casing 16 is slightly larger than the first connecting element 13 and the second connecting element 15, such that there is a gap 25 between the first and second connecting elements 13, 15 and the insulating casing 16, which gap 25 provides a fluid channel 25 fluidly connecting the radial channel parts 22 with the outer fluid channel 7 of the charging cable 2.

[0054] The entire flow path for the coolant fluid is as follows (see in particular FIG. 2, section A and FIG. 3): The coolant fluid flows first along the whole length of the charging cable 2 through the outer fluid channel 7 of the cable 2. At the connection of the charging cable 2 to the charging connector 1, the coolant fluid enters into the gap 25 and continues to flow along the outer surfaces of the first and second connecting elements 13, 15. At the radial surface 24 the fluid enters into the concerning radial channel part 22 and flows through the radial channel parts 22 and the axial channel parts 21 of the fluid channels 20. The fluid exits the axial channel parts 21 at the axial surface 23 of the charging cable mating part 18 and enters into the inner fluid channel 6 of the charging cable 2. Therefore, in this ex-ample, the outer fluid channel 7 provides a supply path for the coolant fluid, while the inner fluid channel 6 provides a return path for the coolant fluid.

[0055] As the flow path first is through the outer fluid channel 7, the fresh and cool coolant fluid first cools the outer surface of the charging cable 2, such that a very good injury prevention for a user is achieved. The highest thermal duty stems from the conductor cooling, which can be handled very easy due to the large con-tact area between the connecting elements 13 15 and the contacts 12, 14, such that heat generated in the contacts 12, 14 during charging can effectively be removed by the liquid coolant. The highest heat flux is expected at the base of the connector 1. The highest temperature of the cooling fluid is to be expected at the return to the charging post, which is uncritical, as the hot cooling fluid is contained in the inner fluid channel 6 of the charging cable and is therefore effectively shielded from the user.

[0056] FIG. 4 and FIG. 5 show a partially cut perspective view of an example of the connector 1, in principle. The set of axial/radial channel parts 21, 22 in the copper block of the connecting element 13, 15 is visualized. The number, position and diameter of the channels 21, 22 is a matter of optimization of thermal performance, manufacturing costs, as well as space constraints due to interface of the channels 21, 22 to the cable 2.

[0057] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the dis-closed embodiments. Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

REFERENCE SIGNS LIST

[0058] 1 charging connector

[0059] 2 charging cable

[0060] 3 positive conductors

[0061] 4 negative conductors

[0062] 5 ground line [0063] 6 inner fluid channel [0064] 7 outer fluid channel [0065] 8 supply path [0066] 9 return path [0067] 10 sheath [0068] 11 sheath [0069] 12 positive contact [0070] 13 first connecting element [0071] 14 negative contact [0072] 15 second connecting element [0073] 16 insulating casing [0074] 17 insulating wall [0075] 18 charging cable mating part [0076] 19 contact mating part [0077] 20 fluid channel [0078] 21 axial channel part [0079] 22 radial channel part

[0080] 23 axial surface [0081] 24 radial surface [0082] 25 gap

[0083] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0084] The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0085] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.