Pane with electrical connection element and connecting element attached thereto

Abstract

The described methods and devices disclose panes with an electrical connection element for motor vehicles with electrically conductive structures such as heating conductors or antenna conductors. The electrically conductive structures may be connected to the vehicle's electrical system via connecting elements. The connecting elements can be flexible connection cables that may be outfitted with a standardized plug connector. According to the disclosed teachings, the process of installing such panes within the vehicle body is simple and time-saving.

Claims

1. A pane with at least one electrical connection element, comprising: a substrate; an electrically conductive structure on a region of the substrate; a bridge-shaped electrical connection element, including a bridge region and two or more soldering feet, which are connected via a soldering compound to a region of the electrically conductive structure; and an electrical connecting element attached to the bridge-shaped electrical connection element, wherein the electrical connecting element is attached to a first surface of the bridge region facing the substrate, or is attached to a second surface of the bridge region facing away from the substrate, routing around the bridge region, and resting against the first surface of the bridge region, wherein a difference between a melting temperature of the bridge-shaped connection element and a melting temperature of the electrical connecting element is greater than 200 C., and wherein the electrical connecting element is attached to the bridge-shaped electrical connection element by a welded connection.

2. The pane according to claim 1, wherein the soldering compound is a lead-free soldering compound.

3. The pane according to claim 1, wherein the difference between the melting temperature of the bridge-shaped electrical connection element and the melting temperature of the electrical connecting element is greater than 300 C.

4. The pane according to claim 1, wherein the electrical connecting element is attached to the bridge-shaped electrical connection element by a welded connection.

5. The pane according to claim 1, wherein the electrical connecting element is a solid metal plate.

6. The pane according to claim 1, wherein the electrical connecting element is a flexible connection cable.

7. The pane according to claim 6, wherein the flexible connection cable is a flat-weave ribbon or a round cable.

8. The pane according to claim 1, wherein the bridge-shaped electrical connection element contains an at least one iron-containing alloy.

9. The pane according to claim 8, wherein the bridge-shaped electrical connection element is formed from chromium-containing steel.

10. The pane according to claim claim 9, wherein the bridge-shaped electrical connection element is formed from 66.5 wt.-% to 89.5 wt.-% iron, 10.5 wt.-% to 20 wt.-% chromium, 0 wt.-% to 1 wt.-% carbon, 0 wt.-% to 5 wt.-% nickel, 0 wt.-% to 2 wt.-% manganese, 0 wt.-% to 2.5 wt.-% molybdenum, 0 wt.-% to 2 wt.-% niobium, and 0 wt.-% to 1 wt.-% titanium.

11. The pane according to claim 1, wherein the electrical connecting element is formed from copper or a copper-containing alloy.

12. The pane according to claim 1, wherein a thickness of the bridge-shaped electrical connection element is from 0.1 mm to 4 mm.

13. The pane according to claim 1, wherein a difference between a coefficient of thermal expansion of the substrate and a coefficient of thermal expansion of the bridge-shaped electrical connection element is less than 510.sup.6/ C.

14. The pane according to claim 1, wherein the substrate is formed from glass.

15. The pane according to claim 14, wherein the the glass is soda lime glass.

16. The pane according to claim 1, wherein the electrically conductive structure is formed from silver and has a layer thickness of 5 m to 40 m.

17. A method of using a pane with at least one electrical connection element, comprising: providing a pane according to claim 1; and using the pane in buildings or in means of transportation for travel on land, in the air, or on water.

18. The pane according to claim 1, wherein the difference between the melting temperature of the bridge-shaped electrical connection element and the melting temperature of the electrical connecting element is greater than 400 C.

19. The pane according to claim 1, wherein a thickness of the bridge-shaped electrical connection element is from 0.2 mm to 2 mm.

20. The pane according to claim 1, wherein a thickness of the bridge-shaped electrical connection element is from 0.4 mm to 1 mm.

21. The pane according to claim 1, wherein a difference between a coefficient of thermal expansion of the substrate and a coefficient of thermal expansion of the bridge-shaped electrical connection element is less than 310.sup.6/ C.

22. The pane according to claim 1, wherein the electrically conductive structure comprises silver particles and glass frits and has a layer thickness of 5 m to 40 m.

23. A method for producing a pane with at least one electrical connection element, the pane including a substrate; an electrically conductive structure on a region of the substrate; a bridge-shaped electrical connection element, including a bridge region and two or more soldering feet, which are connected via a soldering compound to a region of the electrically conductive structure; and an electrical connecting element attached to the bridge-shaped electrical connection element, wherein the electrical connecting element is attached to a first surface of the bridge region facing the substrate, or is attached to a second surface of the bridge region facing away from the substrate, routing around the bridge region, and resting against the first surface of the bridge region, wherein a difference between a melting temperature of the bridge-shaped connection element and a melting temperature of the electrical connecting element is greater than 200 C., and wherein the electrical connecting element is attached to the bridge-shaped electrical connection element by a welded connection, the method comprising: (a) connecting the bridge-shaped electrical connection element to the electrical connecting element; (b) applying the soldering compound on contact surfaces of the soldering feet of the bridge-shaped electrical connection element; (c) arranging the bridge-shaped electrical connection element with the soldering compound on the region of the electrically conductive structure, which is applied on the region of a substrate; and (d) connecting the bridge-shaped electrical connection element to the electrically conductive structure by application of energy.

24. The method of using a pane according to claim 17, wherein the pane is used in rail vehicles or motor vehicles.

25. The method of using a pane according to claim 17, wherein the pane is used in a windshield, a rear window, a side window, or a roof panel.

26. The method of using a pane according to claim 17, wherein the pane is used in a heatable pane or a pane with an antenna function.

Description

(1) The invention is explained in detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and not true to scale. The drawings in no way restrict the invention. They depict:

(2) FIG. 1 an exploded view of an embodiment of the pane according to the invention with an electrical connection element,

(3) FIG. 2 a cross-section through the connection element with a connecting element of FIG. 1,

(4) FIG. 3 another cross-section through the connection element with a connecting element of FIG. 1,

(5) FIG. 4 a cross-section through another embodiment of the connection element according to the invention with a connecting element,

(6) FIG. 5 a flowchart of an embodiment of the production method according to the invention, and

(7) FIG. 6 a flowchart of another embodiment of the production method according to the invention.

(8) FIG. 1 depicts a pane according to the invention (exploded view); FIG. 2 a cross-section along the longitudinal axis of the connection element according to the invention. FIG. 3 depicts another cross-section perpendicular thereto along the longitudinal axis of the connecting element through the bridge region. The pane is, for example, a rear window of a passenger car and comprises a substrate 1, which is a 3-mm-thick thermally prestressed single pane safety glass made of soda lime glass. The substrate 1 has, for example, a width of 150 cm and a height of 80 cm. An electrically conductive structure 2 in the form of a heating conductor structure is printed on the substrate 1. The electrically conductive structure 2 contains silver particles and glass frits. In the edge region of the pane, the electrically conductive structure 2 is widened to a width of roughly 10 mm and forms a contact surface for the electrical connection element 3. The connection element 3 serves for the electrical contacting of the electrically conductive structure 2 to an external power supply via a connection cable (not shown). The electrical contacting is concealed for an observer outside the vehicle by a masking screenprint 6 between the electrically conductive structure 2 and the substrate 1.

(9) The connection element 3 is implemented in the shape of a bridge and has a bridge region 3a and two oppositely arranged soldering feet 3b. Each soldering foot 3b has, on its underside, a flat surface K, wherein the surfaces K of the two soldering feet 3b lie in one plane and form the contact surface of the connection element 3 for soldering. The contact surfaces K are durably connected electrically and mechanically to the electrically conductive structure 2 via a soldering compound 4. The soldering compound 4 is lead-free, contains 57 wt.-% bismuth, 40 wt.-% tin, and 3 wt.-% silver, and has a thickness of 250 m.

(10) A connecting element 5 is attached to the connection element 3. The connecting element 5 is depicted here schematically as a solid platelet, but it can also be implemented as a flexible connection cable, for example, as a flat-weave ribbon.

(11) The connection element 3 and the connecting element 5 have in each case a material thickness of 0.8 mm. Thus, advantageously, a standard-compliant motor vehicle plug connector can be formed from the connecting element 5. If one wishes to use a smaller material thickness for the connecting element 5, a material thickness whose even-numbered multiple yields 0.8 mm is recommended, i.e., for example, 0.4 mm or 0.2 mm, such that the thickness of the standard-compliant plug connector can be obtained by folding. The connection element 3 has, for example, a length of 24 mm and a width of 4 mm. The connecting element 5 has, for example, a width of 6.3 mm and a length of 27 mm.

(12) In order to avoid critical mechanical stresses as a result of temperature changes, the coefficient of thermal expansion of the connection element 3 is coordinated with the coefficient of thermal expansion of the substrate 1. The connection element 3 is made, for example, of chromium-containing steel of the material number 1.4509 in accordance with EN 10 088-2 (ThyssenKrupp Nirosta 4509) with a coefficient of thermal expansion of 10.510.sup.6/ C. in the temperature range from 20 C. to 300 C. Motor vehicle window panes are typically made of soda lime glass, which has a coefficient of thermal expansion of roughly 910.sup.6/ C. Due to the small difference in the coefficients of thermal expansion, critical thermal stresses can be avoided.

(13) The connecting element 5 should have high electrical conductivity and good formability, which is advantageous for contacting with a connection cable. Consequently, the connecting element 5 is made of copper of the material number CW004A (Cu-ETP) with an electrical resistance of 1.8 ohm.Math.cm. The connecting element 5 can, additionally, be tinned for protection against oxidation or silvered to improve electrical conductivity.

(14) The connection element 3 and the connecting element 5 are welded to one another. However, due to the different materials, the welded connection is weakened. Steel of the material number 1.4509 has a melting temperature of approx. 1505 C.; copper, in contrast, approx. 1083 C. The large difference in melting points results in problems during welding. Thus, the connection element 3 must be heated to a very high temperature in order to fuse. In the process, the connecting element 5 can be damaged. The connecting element 5 as a melted and annealed copper part then forms a weak point in the arrangement.

(15) If, as has been the practice until now, the connecting element were arranged on the surface II (top) of the connection element facing away from the substrate 1, the weakened connection could easily result in the detachment (peeling) of the connecting element since, in particular, tensile forces on the connecting element would act directly on this connection. The connecting element 5 could detach from the connection element 3. This effect can already occur at lower tensile forces than acceptable for the motor vehicle industry.

(16) In contrast to the prior art configurations, the connecting element 5 is attached (welded) according to the invention not to the top II but to the surface I (bottom) of the bridge region 3a facing the substrate 1. Tensile forces, which typically have an upward force component (viewed from the substrate 1 outward), are, as it were, diverted around the bridge region 3a and can, consequently, not act directly on the weakened connection. The connection can, consequently, withstand significantly higher tensile forces.

(17) FIG. 4 depicts a cross-section along the longitudinal axis of the connecting element 5 of another embodiment of the invention. The connecting element 5 is welded onto the surface II of the bridge region 3a facing away from the substrate. From there, the connecting element 5 runs around a first side edge of the bridge region 3a and along surface I facing the substrate, against which the connecting element 5 rests with its full surface. The connecting element 5 extends beyond the side edge of the bridge region 3a opposite the first side edge. An electrical connection cable for connection to the vehicle's electrical system can be attached there on the end of the connecting element 5. This embodiment also results in the fact that tensile and leverage forces act on the surface I, which increases the stability of the connection.

(18) Due to the routing of the connecting element 5 around the bridge region 3a, this embodiment is suitable in particular when the connecting element 5 is implemented as a flexible cable. However, even solid connecting elements 5 can be shaped correspondingly.

(19) FIG. 5 and FIG. 6 depict in each case an embodiment of the method according to the invention for producing a pane according to the invention with a connection element 3 according to the invention. The order of the process steps must be interpreted as an exemplary embodiment and does not restrict the invention. Thus, it is, for example, also possible to connect the connecting element 5 to the bridge region 3a only after arranging the soldering compound 4 on the contact surfaces K.

Example 1

(20) A series of bridge-shaped connection elements 3 were welded and fixed according to the invention to a connecting element 5. Subsequently, an upwardly directed tensile force of 200N was exerted on the connecting element 5. The same test was performed with connection elements in which the connecting element was attached according to the prior art to the top II of the connection element 3. The materials were selected in both cases according to the exemplary embodiments in FIGS. 1-3.

(21) In the case of the prior art arrangement, the welded connection broke in 85% of the cases. Breakage was reduced to 0% by the arrangement according to the invention.

Example 2

(22) A tensile test was performed on prior art connection elements and on connection elements 3 according to the invention. An upward directed tensile force, which was steadily increased until breakage of the connection between the connection element 3 and the connecting element 5, was exerted on the connecting elements. The values measured for the maximum tensile force are summarised in Table 1. The measurement values a and b refer to connection elements 3 from different manufacturers.

(23) TABLE-US-00001 TABLE 1 Configuration of the connection element Observed tensile forces at 3 with a connecting element 5 breakage of the connection Prior art: a: 131 N-152 N connecting element 5 welded on the top II of b: 161 N-186 N the bridge region 3a According to the invention: a: 433 N-448 N connecting element 5 welded on the bottom b: 386 N-399 N I of the bridge region 3a According to the invention: a: 316 N-364 N connecting element 5 welded on the top II of b: 408 N-462 N the bridge region 3a and routed around the bridge region 3a, resting against bottom I

(24) From the measurement results, it is clearly discernible that the invention results in an increase in the load-bearing capacity by a factor of 2 to 3. This was unexpected and surprising for the person skilled in the art. Which of the configurations according to the invention delivers greater load-bearing capacity depends on the concrete configuration of the connection element.

LIST OF REFERENCE CHARACTERS

(25) (1) substrate (2) electrically conductive structure (3) bridge-shaped electrical connection element (3a) bridge region of 3 (3b) soldering foot of 3 (4) soldering compound (5) connecting element (6) masking print (I) bottom of 3a, facing the substrate 1 (II) top of 3a, facing away from the substrate 1 (K) contact surface of 3b