Bus bar for a vehicle, and plug-in electric vehicle

Abstract

The invention relates to a bus bar (1A, 1B) which has a rectangular cross section (Q, Q') and an end portion (1A-2) that tapers in plan view of a flat side and comprises a bore (3), wherein the end portion (1A-2) has a greater thickness (d1) than a non-tapered portion (1A-1) located upstream of the end portion (1A-2). The invention also relates to a plug-in electric vehicle (F), having a charging socket with at least two contact elements provided to carry charging current, wherein each of these contact elements is fastened, in particular screwed, to the bore (3) of a respective bus bar (1A, 1B) according to one of the preceding claims. The invention is advantageously applicable in particular to plug-in electric vehicles with a charging socket configured for fast charging, in particular DC voltage fast charging.

Description

[0001] Busbar for vehicle and plug-in electric vehicle

[0002] The invention relates to a busbar with a rectangular cross-section and an end section that tapers toward a flat side when viewed from above, in which end section a bore is located. The invention also relates to a plug-in electric vehicle, comprising a charging socket with at least two contact elements provided for conducting charging current, wherein each of these contact elements is fastened, in particular screwed, to the bore of a respective busbar. The invention is particularly advantageously applicable to plug-in electric vehicles with a charging socket configured for rapid charging, in particular DC rapid charging.

[0003] Particularly at high charging power levels, such as those encountered with DC fast charging of electric vehicles, a significant amount of waste heat is generated in the vehicle's charging socket. Since the temperature at the connection point between the vehicle's internal charging cable and the charging current contact plug or "charging pin" of the charging socket must not exceed 90 degrees Celsius, the charging power is often reduced prematurely. Even with cooled charging stations (guns), the charging cable in the electric vehicle is generally not cooled.

[0004] The charging cable often consists of a copper cable (stranded wire) that is clamped or welded to connectors. The connectors are then connected to the charging pin. These connections create high contact resistance, which can lead to excessive heat generation.

[0005] It is the object of the present invention to at least partially overcome the disadvantages of the prior art and in particular to provide a simple and inexpensive way of reducing heat development in a charging current path of an electric vehicle in the vicinity of a charging current contact plug.

[0006] This object is achieved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims. The object is achieved by a busbar with a rectangular cross-section and an end section that tapers in plan view onto a flat side and in which a bore is located, wherein the end section has a greater thickness than a non-tapered section located in front of the end section.

[0007] The thickening of the busbar in the area where the flat sides taper counteracts the cross-sectional reduction caused by the taper. This, in turn, keeps electrical resistance within the busbar low in the area of ​​the hole used to connect to the charging pin, which already reduces heat generation there. Furthermore, the inner surface of the hole is enlarged, which reduces contact resistance between the charging pin and the busbar and thus also reduces heat generation.

[0008] The hole is used for connection, in particular direct screwing of a charging pin.

[0009] A busbar is understood, in particular, to be a rigid or only slightly flexible, possibly plastically bendable, power line made of metal. The metal can be copper or aluminum, for example. The fact that the busbar has a rectangular cross-section can, in particular, mean that it has two opposite sides with a smaller ("cross-sectional") length and two opposite sides with a larger ("cross-sectional") length. The sides with a smaller cross-sectional length can, for example, be tapered towards each other in the manner of an isosceles, be tapered parallel to each other in the manner of a parallelogram, or be perpendicular to the sides with a larger cross-sectional length in the manner of a rectangle. It is also possible for the sides with a smaller cross-sectional length to be curved, e.g., mirror-symmetrically, etc.The "larger cross-sectional length" can also be referred to as the width of the busbar, and the vertical distance between them is the thickness of the busbar. The thickness corresponds to the "smaller cross-sectional length," especially in the case of a rectangular cross-section.

[0010] The sides with the larger cross-sectional length form the flat sides of the busbar in plan view. The fact that the busbar has an end section that tapers toward a flat side in plan view includes, in particular, that it has a non-tapering section of constant width, which, in the longitudinal extension of the busbar, transitions at at least one end into a tapered section ("end section") with, in particular, a continuously decreasing width.

[0011] In the non-tapering section, the busbar is particularly profile-like with a constant width and thickness. It can be straight and / or curved there. The fact that the end section has a greater thickness than the non-tapering or non-tapering section located in front of the end section means, in particular, that the end section is thickened at least in some areas there, in particular, that it is thickened at least circumferentially around the bore, in particular, that it is thickened everywhere or completely.

[0012] One embodiment is such that the value of the cross-sectional area along its longitudinal extent, or the cross-sectional size of the end section, remains at least approximately constant along its longitudinal extent. This provides the advantage that an ohmic resistance for the charging current in the end section does not vary or varies only slightly.

[0013] One embodiment is such that the thickness in the end section changes at least approximately inversely proportional to the degree of tapering with respect to a longitudinal position. Thus, if the width at a position along the longitudinal extent of the end section is smaller by a factor f, with 0 < f < 1, compared to the non-tapered section, the thickness there is greater by a factor of 1 / f than at the non-tapered section.

[0014] In a further development, the thickness at least at one point of the end section, in particular in a partial section of the end section, is at least between 25% and 100% thicker than the non-tapered section located in front of the end section. It has proven particularly advantageous for the thickness of the end section at least at one point of the end section, in particular in a partial section of the end section, to be at least between 50% and 100% thicker than the non-tapered section located in front of the end section.

[0015] One embodiment provides that the thickness of the end section remains constant within at least a partial section of the end section. This is particularly easy to implement. A further development provides that the thickness of the end section remains constant around the bore. This advantageously facilitates a flat attachment of a contact element, e.g., a nut, to the area around the bore.

[0016] One embodiment provides that the end section is a substantially continuously tapered end section (toward its end). This advantageously facilitates dimensioning of a thickened portion to achieve a practically non-constantly changing, in particular at least approximately constant, ohmic resistance along the longitudinal extent.

[0017] This embodiment can be implemented particularly simply, for example, in that a (in plan view) first side edge of the busbar continues at least substantially straight ahead with the start of the end section, while an opposite second side edge with the start of the end section runs obliquely, in particular straight, in the direction of the first side edge, in particular without meeting the first side edge.

[0018] In one embodiment, the end section has been produced by a flat-sided material-to-material bonding of a semi-finished product of constant thickness, which in plan view is in the form of a busbar, to a workpiece providing the greater thickness in the region of the end section. This can be particularly advantageous from a manufacturing perspective because, in order to produce the greater thickness, the busbar itself, which is in the form of a semi-finished product, does not need to be reshaped for this purpose. The material-to-material bonding can be achieved, for example, by pressing, friction welding, etc. Alternatively, the busbar, which is in the form of a semi-finished product, can be thickened in the future end section by forming, for example by pressing, hammering, etc. Advantageously, the bore is only created after the thickening has taken place.

[0019] One design is that the busbar is made of aluminum. Aluminum is advantageously particularly lightweight and inexpensive.

[0020] The object is also achieved by an electric vehicle having at least one charging rail as described above. The electric vehicle can be designed analogously to the busbar, and vice versa, and has the same advantages. In one embodiment, the electric vehicle is a plug-in electric vehicle having a charging socket with at least two contact elements provided for conducting charging current, wherein each of these contact elements is fastened, in particular screwed, to the bore of a respective busbar as described above. The plug-in electric vehicle can be a hybrid vehicle (PHEV) or a fully electrically powered vehicle (PBEV).

[0021] It is a further development that the plug-in electric vehicle is equipped for direct current fast charging (so-called "DC charging").

[0022] The charging rail is used in particular to conduct a charging current for charging or discharging between a drive battery of the plug-in electric vehicle and a corresponding charging pin.

[0023] The charging socket can optionally also have additional contact elements, in particular contact pins, for example for data communication.

[0024] One embodiment involves at least two such busbars being electrically insulated from each other in a layered arrangement. This facilitates installation on two charging pins, which can be assigned to a positive or negative pole, for example. For example, the busbars can be placed flat against each other, separated by an electrically insulating layer.

[0025] One embodiment involves two such busbars being arranged in a mirror-image manner, so that their holes are positioned side by side in plan view and are each exposed. This further facilitates assembly. The exposed holes can, in particular, mean that the hole in one of the busbars is not covered by the other busbar.

[0026] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following schematic description of an embodiment, which is explained in more detail in conjunction with the drawings. Figure 1 shows a plan view of a vehicle conductor rail line according to the invention;

[0027] Fig.2 shows the busbar cable according to the invention from Fig.1 as a longitudinal section in side view;

[0028] Fig.3 shows a cross-section through a non-thickened section of the busbar of the busbar line from Fig.1; and

[0029] Fig.4 shows a cross-section through a thickened section of the busbar of the busbar line from Fig.1.

[0030] Fig. 1 shows a top view of a busbar line 1 according to the invention of a vehicle F, in particular a plug-in electric vehicle. Fig. 2 shows the busbar line 1 as a longitudinal section in a side view.

[0031] The busbar line 1 has two busbars 1A and 1B, which are arranged mirror-symmetrically on top of one another or one above the other along their common longitudinal extent L and are separated from one another by an electrical insulating layer 2. This can also be expressed as the two busbars 1A and 1B, which are arranged mirror-symmetrically to one another in plan view, being combined in layers and electrically insulated from one another. In particular, the two busbars 1A and 1B can have the same shape but are simply arranged in a mirror-inverted manner. In the present case, the busbar 1A is arranged above the busbar 1B in plan view. These two busbars 1A and 1B can be made of copper or aluminum, for example, and can electrically connect, for example, the charging pins of a charging socket (not shown) to a drive battery (not shown) of the vehicle.

[0032] As shown in Fig. 3, the busbar 1A, in its profile-like, non-tapering section 1A-1, has a rectangular cross-section with two opposite sides of shorter length SK and two opposite sides of longer length SL. The length of the sides SK corresponds to the thickness d of section 1A-1, and the length of the sides SL corresponds to the width b of section 1A-1. The area Q of the cross-section is then calculated as Q = b • d.

[0033] Towards at least one end, the non-tapering section 1A-1 merges into an end section 1A-2 which, in plan view, continuously tapers and in which a bore 3 is located. The bores 3 are arranged next to one another in plan view and are each exposed.

[0034] A taper is understood to mean that the width b' of the busbar 1A in the end section 1A-2 also decreases with decreasing distance to the end. The taper is achieved in the present case in that a first side edge R1 of the busbar 1A (shown here as the upper side edge) continues to run at least substantially (here: except for a rounded end) straight ahead or parallel to the longitudinal extent L, while a second side edge R2 (shown here as the lower side edge) runs at the beginning of the end section in a straight line obliquely in the direction of the first side edge R1, in particular without meeting the first side edge R1.

[0035] As shown in Fig. 4, the end section 1A-2 has a greater thickness d' than section 1A-1. Thus, d' > d and b > b'. In this case, the thickness d' initially increases linearly, for example, such that Q' = b' • d' » b • d = Q. Subsequently, and before reaching the bore 3, the thickness d' of the end section 1A-2 is kept constant.

[0036] The end section 1A-2 can, for example, be produced by a flat-side, materially bonded connection of a semi-finished product 4, which in plan view is in the form of a busbar, of constant thickness d, to a workpiece 5 providing the greater thickness d' in the region of the end section 1A-2. For example, the workpiece 5 can be attached to the semi-finished product 4 by friction welding.

[0037] The busbar 1 B can be designed analogously, in particular identically.

[0038] Of course, the present invention is not limited to the embodiment shown.

[0039] In general, "a", "an", etc., can be understood as a singular or a plural, in particular in the sense of "at least one" or "one or more", etc., as long as this is not explicitly excluded, e.g. by the expression "exactly one", etc. A numerical specification can also include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded.

[0040] List of reference symbols

[0041] 1 conductor rail line

[0042] 1A power rail

[0043] 1 A-1 Non-tapered section of the busbar

[0044] 1 A-2 Tapered section of the busbar

[0045] 1 B busbar

[0046] 2 Insulating layer

[0047] 3 Hole

[0048] 4 Semi-finished product

[0049] 5 Workpiece b Width of the non-tapered section b' Width of the tapered section d Thickness of the non-tapered section d' Thickness of the tapered section

[0050] F vehicle

[0051] R1 page margin

[0052] R2 page margin

[0053] SK side of shorter length

[0054] SL side of greater length

Claims

Patent claims 1. Busbar (1A, 1B) with a rectangular cross-section (Q, Q') and an end section (1A-2) tapering in plan view onto a flat side, in which a bore (3) is located, wherein the end section (1A-2) has a greater thickness (d 1 ) than a non-tapered section (1A-1) located in front of the end section (1A-2).

2. Busbar (1A, 1B) according to claim 1, wherein the area of the cross section (Q 1 ) of the end section (1A-2) along its longitudinal extent (L) remains at least approximately constant at least in a partial section.

3. Busbar (1A, 1B) according to claim 2, wherein the thickness (d 1 ) in the end section (1A-2) with respect to a longitudinal position changes at least approximately inversely proportional to a degree of taper.

4. Busbar (1A, 1B) according to claim 1, wherein the thickness (d 1) of the end section (1A-2) remains constant within at least a partial section of the end section (1A-2).

5. Busbar (1A, 1B) according to one of the preceding claims, wherein the end section (1A-2) is a continuously tapered end section (1A-2).

6. Busbar (1A, 1B) according to claim 5, wherein a first side edge (R1) of the busbar (1A, 1B) continues at least substantially straight ahead with the beginning of the end section (1A-2), while a second side edge (R2) with the beginning of the end section (1A-2) runs obliquely, in particular straight, in the direction of the first side edge (R1), in particular without meeting the first side edge (R1).

7. Busbar (1 A, 1 B) according to one of the preceding claims, wherein the end section (1A-2) is formed by a flat-sided material connection of a semi-finished product (4) of constant thickness (d) present in the form of the busbar (1A, 1 B) in plan view with a greater thickness (d1 ) in the region of the workpiece (5) providing the end section (1A-2).

8. Busbar (1A, 1B) according to one of the preceding claims, wherein the busbar (1A, 1B) is made of aluminum.

9. Plug-in electric vehicle (F), comprising a charging socket with at least two contact elements provided for conducting charging current, wherein each of these contact elements is fastened, in particular screwed, to the bore (3) of a respective busbar (1A, 1B) according to one of the preceding claims.

10. Plug-in electric vehicle (F) according to claim 9, wherein at least two such busbars (1A, 1B) are combined in layers so as to be electrically insulated from one another.

11. Plug-in electric vehicle (F) according to claim 10, wherein two busbars (1A, 1B) are arranged mirror-inverted one on top of the other such that their bores (3) are arranged next to one another and are each exposed in plan view.

Images