Relay and battery system including the same

Abstract

A relay including a relay coil and a relay switch. The relay coil including a coil beginning and a coil end and being connected to a relay driving circuit. The relay switch being arranged in a load circuit. A first parasitic capacitance between the coil beginning and the relay switch is different than a second parasitic capacitance between the coil end and the relay switch.

Claims

1. A relay comprising: a relay coil comprising a coil beginning and a coil end, the relay coil being connected to a relay driving circuit; and a relay switch arranged in a load circuit, wherein a first parasitic capacitance between the coil beginning and the relay switch is different than a second parasitic capacitance between the coil end and the relay switch, and wherein one of the first parasitic capacitance and the second parasitic capacitance is arranged in a capacitive coupling path of electromagnetic interference between the relay driving circuit and the load circuit to attenuate or dissipate the electromagnetic interference.

2. The relay according to claim 1, wherein the relay switch comprises a relay pallet, and wherein the first parasitic capacitance is between the coil beginning and the relay pallet, and the second parasitic capacitance is between the coil end and the relay pallet.

3. The relay according to claim 1, wherein the smaller one of the first parasitic capacitance and the second parasitic capacitance is arranged in a capacitive coupling path of electromagnetic interference between the relay driving circuit and the load circuit to attenuate the electromagnetic interference.

4. The relay according to claim 1, wherein the larger one of the first parasitic capacitance and the second parasitic capacitance is arranged in a capacitive coupling path of electromagnetic interference between the relay driving circuit and the load circuit to dissipate the electromagnetic interference.

5. The relay according to claim 1, wherein one of the coil beginning and the coil end is connected to ground via a third node and a switch, wherein the other one of the coil beginning and the coil end is connected to a supply voltage via a fourth node, and wherein the switch is configured to be controlled by a PWM controller.

6. The relay according to claim 5, wherein a source of electromagnetic interference between the relay driving circuit and the load circuit is arranged in the relay driving circuit, and wherein the smaller one of the first parasitic capacitance and the second parasitic capacitance is connected to the third node.

7. The relay according to claim 6, wherein the PWM controller is the source of the electromagnetic interference between the relay driving circuit and the load circuit.

8. The relay according to claim 5, wherein a source of electromagnetic interference between the relay driving circuit and the load circuit is arranged in the load circuit, and wherein the smaller one of the first parasitic capacitance and the second parasitic capacitance is connected to the fourth node.

9. The relay according to claim 1, wherein the second parasitic capacitance is smaller than the first parasitic capacitance.

10. A battery system comprising: a plurality of battery cells electrically connected to each other in series between a first node and a second node; and the relay according to claim 1, wherein the load circuit is configured to connect the battery cells and an external load to each other, and wherein the relay switch is interconnected between the first node or the second node and the external load.

11. The battery system according to claim 10, further comprising an inverter in the load circuit, the inverter being a source of electromagnetic interference between the relay driving circuit and the load circuit, wherein the smaller one of the first parasitic capacitance and the second parasitic capacitance is connected to a fourth node.

12. A method for improving electromagnetic compatibility of a relay, the relay comprising: a relay coil having a coil beginning and a coil end and being connected to a relay driving circuit; and a relay switch arranged in a load circuit, the method comprising: determining a first parasitic capacitance between the coil beginning and the relay switch; determining a second parasitic capacitance between the coil end and the relay switch; determining electromagnetic interference between the relay driving circuit and the load circuit; determining a polarity of the relay coil in the relay driving circuit according to the determined first parasitic capacitance, the determined second parasitic capacitance, and the determined electromagnetic interference; and arranging one of the first parasitic capacitance and the second parasitic capacitance in a capacitive coupling path of electromagnetic interference between the relay driving circuit and the load circuit to attenuate or dissipate the electromagnetic interference.

13. The method according to claim 12, further comprising: arranging the smaller one of the first parasitic capacitance and the second parasitic capacitance in a capacitive coupling path of the electromagnetic interference between the relay driving circuit and the load circuit to attenuate the electromagnetic interference.

14. The method according to claim 13, further comprising: arranging the larger one of the first parasitic capacitance and the second parasitic capacitance in a capacitive coupling path of the electromagnetic interference between the relay driving circuit and the load circuit to conduct the electromagnetic interference away via the capacitive coupling path.

15. The method according to claim 13, wherein the capacitive coupling path comprises a vehicle chassis.

16. The method according to claim 12, further comprising: arranging the larger one of the first parasitic capacitance and the second parasitic capacitance in a capacitive coupling path of the electromagnetic interference between the relay driving circuit and the load circuit to conduct the electromagnetic interference away via the capacitive coupling path.

17. The method according to claim 16, wherein the capacitive coupling path comprises a vehicle chassis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Aspects and features of the present invention will become apparent to those of ordinary skill in the art by describing, in detail, exemplary embodiments thereof with reference to the attached drawings in which:

(2) FIG. 1 is a schematic illustration of a battery system according to an embodiment;

(3) FIG. 2 is a schematic illustration of a relay according to an embodiment;

(4) FIG. 3 is a schematic illustration of a detailed view of the relay shown in FIG. 2;

(5) FIG. 4 is a schematic illustration of a relay according to an embodiment;

(6) FIG. 5 is a schematic illustration of a relay according to an embodiment;

(7) FIG. 6 is a schematic illustration of a relay according to an embodiment;

(8) FIG. 7 is a schematic illustration of an electric vehicle according to an embodiment; and

(9) FIG. 8 is a schematic illustration of a high-voltage (HV) battery system according to an embodiment.

DETAILED DESCRIPTION

(10) Reference will now be made in detail to example (or exemplary) embodiments, which are illustrated in the accompanying drawings. Aspects and features of the exemplary embodiments, and implementation methods thereof, will be described with reference to the accompanying drawings. In the drawings, like reference numerals denote like elements, and redundant descriptions thereof may be omitted. The present invention, however, may be embodied in various different forms and should not be construed as being limited to the illustrated embodiments. Further, descriptions of processes, elements, and techniques that are well-known by those having ordinary skill in the art (e.g., descriptions of processes, elements, and techniques that are not considered necessary for those having ordinary skill in the art to have a complete understanding of the aspects and features of the present invention) may be omitted. Further, in the drawings, the relative sizes of elements, layers, and regions may be exaggerated for clarity.

(11) It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected, or coupled to the other element or layer or one or more intervening elements or layers may also be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. For example, when a first element is described as being “coupled” or “connected” to a second element, the first element may be directly coupled or connected to the second element or the first element may be indirectly coupled or connected to the second element via one or more intervening elements.

(12) Also, the term “exemplary” is intended to refer to an example or illustration. As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.

(13) It will be understood that although the terms “first,” “second,” etc. may be used to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. For example, a first element may be named a second element and, similarly, a second element may be named a first element, without departing from the scope of the present invention.

(14) Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” or “over” the other elements or features. Thus, the term “below” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

(15) As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Further, the use of “may” when describing embodiments of the present invention refers to “one or more embodiments of the present invention.” In the following description of embodiments of the present invention, the terms of a singular form may include plural forms unless the context clearly indicates otherwise.

(16) As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. Further, if the term “substantially” is used in combination with a feature that could be expressed using a numeric value, the term “substantially” denotes a range of +/−5%.

(17) FIG. 1 is a schematic view of a battery system 50 according to an embodiment. In the battery system 50, ones of a plurality of battery cells 40 are connected to each other in series between a first node 41 and a second node 42. The battery cells 40 may also be connected to each other in parallel between the first node 41 and the second node 42, forming an XsYp configuration between these nodes 41, 42. In some embodiments, battery submodules may be connected between these nodes 41, 42.

(18) Each of the twelve battery cells 40 may provide a voltage of approximately 4 V such that a voltage VDD of approximately 48 V is applied (e.g., is generated or transmitted) between the first node 41 and the second node 42. However, other voltages may be applied between the first node 41 and the second node 42. An external load 60 is supplied with this voltage of the battery cells 40. A relay switch (e.g., a holder relay switch or a relay) 4 is interconnected as power switch between the first node 41 and the external load 60 and is controlled via a relay coil 3 to control the power supply to the external load 60.

(19) The relay coil 3 is controlled via the relay driving circuit 11, and the relay driving circuit 11 is configured to control the relay coil 3 for emergency cut off between the battery cells 40 and the external load 60. The relay driving circuit 11 may be configured to control the current provided to the relay coil 3 via pulse width modulation (PWM) (e.g., via a PWM signal) applied to the holding relay switch 4 via the relay coil 3.

(20) The relay driving circuit 11 receives a differential input via two input nodes that are connected upstream and downstream, respectively, of a shunt resistor 43 that is interconnected between the second node 42 and the external load 60. Hence, these input nodes provide a voltage drop over the shunt resistor 43 as an input signal to the relay driving circuit 11 to cut off the battery cells 40 from the external load 60 in an overcurrent situation. The relay driving circuit 11 may receive other input signals, such as signals related to temperatures of the battery cells 40, or may not receive any input signal at all.

(21) FIGS. 2 and 3 illustrate a relay 1 according to an embodiment. The relay 1 includes a relay coil 3 and a relay switch 4 as primary components. These components may be considered parts of the relay 1 but may also be considered parts of the relay driving circuit 11. The relay coil 3 includes a coil wire that is helically wound on (e.g., around) a hollow cylindrical core so as to form a hollow cylindrical coil 3. A relay pallet 2 is disposed in the central cavity of the relay coil 3 and is connected to the relay switch 4. Thus, a magnetic field generated by the relay coil 3 actuates the relay switch 4 via the relay pallet 2. The relay switch 4 is arranged in a load circuit 10 and is configured to allow a current to flow in (or through) the load circuit 10 (e.g., in a closed state) or to cut a current in the load circuit (e.g., in an open state). As shown in FIG. 3, the relay coil 3 is arranged within a magnetic bucket 7 that also has a hollow cylindrical form and fits the coil 3.

(22) As further shown in the cross-sectional view of FIG. 3, the relay coil 3 has a thickness in a radial direction as it is formed of multiple layers of wound coil wire. For example, the coil wire is wound around a core (e.g., around the relay pallet 2) starting with a coil beginning 5 forming an innermost layer of the relay coil 3. The coil wire is then wound around the core multiple times until a coil end 6 is laid upon an outermost layer of the relay coil 3. As indicated by the dotted lines in FIG. 3, a first parasitic capacitance 8 is formed between the coil beginning 5 and the relay pallet 2, and a second parasitic capacitance 9 is formed between the coil end 6 and the relay pallet 2.

(23) FIG. 4 schematically illustrates a wiring diagram of a relay 1 according to an embodiment. The relay 1 includes a low voltage (LV) relay driving circuit 11 including a relay coil and a high voltage (HV) load circuit 10 including a relay switch 4 that is controlled by the relay coil 3. In the relay driving circuit 11, the coil beginning 5 is connected to a LV supply voltage VDD 16 via a fourth node 17. The coil end 6 is connected to ground 14 via a third node 15 and a switch 13. The switch 13 is controlled via a PWM controller 18 that opens and closes the switch 13 based on a PWM signal. A freewheeling diode 12 is connected in parallel with the relay coil 3 between the third node 15 and the fourth node 17 with its anode pointing to the third node 15.

(24) As illustrated in the extended wiring diagram of FIG. 5, a first parasitic capacitance C.sub.P 8 is formed between the relay beginning 5 and the load circuit 10 (e.g., between the relay beginning 5 and the relay switch 4), and a second parasitic capacitance C.sub.P 9 is formed between the relay end 6 and the load circuit 10 (e.g., between the relay end 6 and the relay switch 4). The difference in the links of the parasitic capacitances C.sub.P 8, 9 to the load circuit 10 (e.g., the relay switch 4) is for illustrative purposes only. The parasitic capacitances C.sub.P 8, 9 both link to the relay switch 4 (e.g., the relay pallet 2). The first parasitic capacitance C.sub.P 8 is greater than the second parasitic capacitance C.sub.P 9 as a distance between the coil beginning 5 and the relay pallet 2 is smaller than between the coil end 6 and the relay pallet 2 (see, e.g., FIG. 3). A third parasitic capacitance C.sub.P 19 is formed in parallel with the relay coil 3.

(25) FIG. 6 shows an abstract wiring diagram of the relay 1 as a four pole relay according to an embodiment. The load circuit 10 is illustrated with closed relay switch 4 (e.g., with the relay switch 4 in a closed state). Further, the first parasitic capacitance 8 is illustrated as first complex parasitic coupling impedance Z.sub.P1, and the second parasitic capacitance 9 is illustrated as second complex parasitic coupling impedance Z.sub.P2. Further, the relay coil 3 and the third parasitic capacitance 19 are together illustrated as complex coil impedance 22. In FIG. 6, the first complex parasitic coupling impedance Z.sub.P1 is different than (e.g., is unequal from) the second complex parasitic coupling impedance Z.sub.P2 due to the relay coil's 3 asymmetry with respect to coil beginning 5 and end 6 as shown in, for example, FIG. 3.

(26) When the first complex parasitic coupling impedance Z.sub.P1 is smaller than the second complex parasitic coupling impedance Z.sub.P2, electromagnetic interference (EMI) transmission between the load circuit 10 and the relay driving circuit 11 occurs predominantly via the first complex parasitic coupling impedance Z.sub.P1. When the PWM signal provided by the PWM controller 18 is the most significant source of EMI in the relay 1, this signal would then not strongly couple into the load circuit 10. However, when a main (or predominant or primary) source of EMI is located within the load circuit 10, the coil beginning 5 should be connected to the third node 15. In this embodiment, EMI transmission between the load circuit 10 and the relay driving circuit 11 would again predominantly occur via the first complex parasitic coupling impedance Z.sub.P1 such that any EMI emitted by load circuit 10 would then predominantly be conducted away to ground via Z.sub.P1 and the third node 15.

(27) FIG. 7 schematically illustrates an electric vehicle according to an embodiment. The electric vehicle includes a relay driving circuit 11 and a load circuit 10, such as is illustrated in FIG. 6. For illustrative purposes, the first and second parasitic coupling impedances 20, 21 are connected to the same node (e.g., the relay driving circuit 11 is illustrated as a three pole relay). Further, line losses between the relay beginning 5 and the fourth node 17 shown in FIG. 6 as well as the influences of the supply voltage VDD 16 are summarized as fourth coupling impedance 23. Similarly, line losses between the relay end 6 and the third node 15 shown in FIG. 6 as well as the influences of switch 13 and PWM controller 18 are summarized as fifth coupling impedance 24.

(28) In the vehicle shown in FIG. 7, a vehicle chassis 25 is capacitively coupled to both the load circuit 10 and to the supply voltage node 17 (see, e.g., FIG. 6) of the relay driving circuit 11. Hence, a capacitive coupling path exists from the load circuit 10 via the first parasitic coupling impedance 20 to the coil beginning 5 and from the relay driving circuit 11 to the vehicle chassis 25 via the fourth coupling impedance 23 and from there back to the load circuit 10. This coupling path has a high total coupling capacity and, thus, a low total coupling impedance.

(29) By turning (e.g. winding) the relay coil 3 such that the second parasitic coupling impedance Z.sub.P2 21 is disposed within this coupling path instead of the first parasitic coupling impedance Z.sub.P1 20 (e.g., by connecting the coil end 6 to the fourth node 17 instead of the coil beginning 5), the total coupling capacity of the coupling path is reduced or minimized and, hence, the total coupling impedance of the coupling path is increased or maximized. Thus, any EMI transmission between load circuit 10 and relay driving circuit 11 across this coupling path is attenuated.

(30) FIG. 8 schematically illustrates a high-voltage (HV) battery system according to an embodiment. The HV battery system includes a HV load circuit 10 and a relay driving circuit 11 that are configured similar to the similar circuits shown in FIG. 6. For illustrative purposes, the first and second parasitic coupling impedances 20, 21 are connected to the same node (e.g., the relay driving circuit 11 is illustrated as a three pole relay). Further, line losses between the relay end 6 and the fourth node 17 shown in FIG. 6 as well as the influences of the supply voltage VDD 16 are summarized as fourth coupling impedance 23. Also, line losses between the relay beginning 5 and third node 15 shown in FIG. 6 and the influences of the switch 13 and the PWM controller 18 are summarized as fifth coupling impedance 24.

(31) In the battery system shown in FIG. 8, a capacitive coupling path exists from the load circuit 10 to the coil beginning 5 via the first parasitic coupling impedance Z.sub.P1 20 and from the relay driving circuit 11 to the load circuit 10 via the fifth coupling impedance 24. Again, this coupling path has a high total coupling capacity and, thus, a low total coupling impedance.

(32) By positioning the relay coil 3 such that the second parasitic coupling impedance Z.sub.P2 21 is disposed within this coupling path instead of the first parasitic coupling impedance Z.sub.P1 20 (e.g., by connecting the coil end 6 to the third node 15 instead of connecting the coil beginning 5 to the third node 15), the total coupling capacity of the coupling path is reduced or minimized and, hence, the total coupling impedance of the coupling path is increased or maximized. Thus, any EMI transmission between load circuit 10 and relay driving circuit 11 across this coupling path is attenuated.

(33) The electronic or electric devices and/or any other relevant devices or components according to embodiments of the present invention described herein may be implemented utilizing any suitable hardware, firmware (e.g. an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices may be formed on one integrated circuit (IC) chip or on separate IC chips. Further, the various components of these devices may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on one substrate. The electrical connections or interconnections described herein may be realized by wires or conducting elements, for example, on a PCB or another kind of circuit carrier. The conducting elements may include (or may be formed of) metallization, such as surface metallizations and/or pins, and/or may include conductive polymers or ceramics. Further, electrical energy might be transmitted via wireless connections by using, for example, electromagnetic radiation and/or light.

(34) Further, the various components of these devices may be a process or thread, running on one or more processors, in one or more computing devices, executing computer program instructions and interacting with other system components for performing the various functionalities described herein. The computer program instructions may be stored in a memory which may be implemented in a computing device by using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer readable media such as, for example, a CD-ROM, flash drive, or the like.

(35) A person of skill in the art should recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of the exemplary embodiments of the present invention.

SOME REFERENCE SIGNS

(36) 1 relay 2 relay pallet 3 relay coil 4 relay switch 5 relay coil beginning 6 relay coil end 7 magnetic bucket 8 first parasitic capacitance 9 second parasitic capacitance 10 HV battery system (e.g., load circuit) 11 relay driving circuit 12 freewheeling diode 13 switch 14 ground 15 third node 16 supply voltage 17 fourth node 18 PWM controller 19 third parasitic capacitance 20 first parasitic coupling impedance 21 second parasitic coupling impedance 22 complex coil impedance 23 fourth coupling impedance 24 fifth coupling impedance 25 vehicle chassis 40 battery cell 41 first node 42 second node 43 shunt resistor 50 battery system 60 external load