Power switch, battery system and method for operating a power switch

Abstract

The invention relates to a power switch (100) for a battery system. The power switch (100) comprises: a first terminal (104); a second terminal (106); a control terminal (102) for receiving a control signal (108); a device (112) for identifying a power switching signal (114) and a communication signal (116) based on the control signal (108); a power section (118) comprising at least one switch (122) for switching an electrical connection between the first terminal (104) and the second terminal (106) based on the power switching signal (114); and a communication section (120) comprising at least one switch (124) for switching the electrical connection between the first terminal (104) and the second terminal (106) based on the communication signal (116).

Claims

1. A power switch (100) for a battery system (750), the power switch (100) comprising: a first terminal (104); a second terminal (106); a control terminal (102) configured to receive a control signal (108); a device (112) for defining a power switching signal (114) and a communication signal (116) using the control signal (108); a power section (118) with at least one first switch (122) for switching an electrical connection between the first terminal (104) and the second terminal (106) using the power switching signal (114); and a communication section (120) with at least one second switch (124) for switching the electrical connection between the first terminal (104) and the second terminal (106) based on the communication signal (116).

2. The power switch (100) as claimed in claim 1, wherein the defining device (112) is configured to define the power switching signal (114) as a first signal component of the control signal (108) and the communication signal (116) as a second signal component of the control signal (108).

3. The power switch (100) as claimed in claim 1, wherein the defining device (112) has a low-pass filter (430) and a high-pass filter (432) and is configured to filter the control signal (108) using the low-pass filter (430) in order to define the power switching signal (114) with low-frequency signal components of the control signal (108) and to filter the control signal (108) using the high-pass filter (432) in order to define the communication signal (116) with high-frequency signal components of the control signal (108).

4. The power switch (100) as claimed in claim 1, wherein the power section (118) has a plurality of first switches (122) that are controlled using the power switching signal (114).

5. The power switch (100) as claimed in claim 1, wherein the communication section (120) has a plurality of second switches (124) that are controlled using the communication signal (116).

6. The power switch (100) as claimed in claim 4, wherein a number of the first switches (122) of the power section (118) is larger than a number of the second switches (124) of the communication section (120).

7. The power switch (100) as claimed in claim 1, wherein the at least one first switch (122) of the power section (118) and the at least one second switch (124) of the communication section (120) are parallel-connected between the first terminal (104) and the second terminal (106).

8. The power switch (100) as claimed in claim 1, wherein it is designed as a semiconductor component.

9. The power switch (100) as claimed in claim 1, wherein it is designed the power switch (100) is configured to use the at least one first switch (122) and the at least one second switch (124) to switch an electric current of more than 100 amps between the first terminal (104) and the second terminal (106).

10. A battery system (750) with the following features: at least one battery cell (756); a power switch (100) as claimed in claim 1, wherein the first terminal (104) of the power switch (100) is coupled to a connection contact of the at least one battery cell (765); and a control device (752) configured to deliver the control signal (108) to the control terminal (102) of the power switch (100).

11. A method for operating a power switch (100) for a battery system (750), wherein the power switch (100) has a first terminal (104), a second terminal (106), a control terminal (102), a power section (118) with at least one first switch (122) and a communication section (120) with at least one second switch (124), the method comprises: defining (602) a power switching signal (114) and a communication signal (116) using a control signal (108) present on the control terminal (102); using (604) the power switching signal (114) to switch an electrical connection between the first terminal (104) and the second terminal (106) using the at least one first switch (122) of the power section (118); and using (606) the communication signal (116) to switch the electrical connection between the first terminal (104) and the second terminal (106) using the at least one second switch (124) of the communication section (120).

12. A non-transitory computer readable medium including a program for carrying out all steps of the method as claimed in claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The approach presented here will be described in more detail below by way of examples with reference to the appended drawings, in which:

(2) FIG. 1 shows a block diagram of a power switch according to one exemplary embodiment of the present invention;

(3) FIG. 2 shows a schematic representation of a power switch according to one exemplary embodiment of the present invention;

(4) FIG. 3 shows a block diagram of a power switch for a battery system;

(5) FIG. 4 shows a block diagram of a power switch for a battery system according to one exemplary embodiment of the present invention;

(6) FIG. 5 shows a simplified representation of normalized signals of a power switch for a battery system;

(7) FIG. 6 shows a flowchart of a method for operating a power switch for a battery system according to one exemplary embodiment of the present invention; and

(8) FIG. 7 shows a battery system according to one exemplary embodiment of the present invention.

DETAILED DESCRIPTION

(9) In the following description of favorable exemplary embodiments of the present invention, the same or similar references will be used for the elements represented in the various figures and functioning in a similar manner, thereby avoiding a repeated description of these elements.

(10) FIG. 1 shows a block diagram of a power switch 100 according to one exemplary embodiment of the present invention. The power switch 100 has three terminals 102, 104, 106. A control terminal 102 is designed to receive a control signal 108. The power switch 100 is designed to switch or to make an electrical connection between the first terminal 104 and the second terminal 106 under the control of the control signal 108. The power switch 100 has a device 112 for defining a power switching signal 114 and a communication signal 116. The defining device 112 is designed to define the power switching signal 114 and the communication signal 116 using the control signal 108. The power switch 100 has a power section 118 and a communication section 120. The power section 118, comprising at least one first switch 122, is designed to make the electrical connection between the first terminal 104 and the second terminal 106 using the power switching signal 114. The communication section 120, comprising at least one second switch 124, is designed to make the electrical connection between the first terminal 104 and the second terminal 106 using the communication signal 116.

(11) In one exemplary embodiment, the power switch 100 is used for superposed data communication for a battery system, as shown in FIG. 7. The battery is employed, for example, in an electric vehicle or a hybrid vehicle.

(12) In one exemplary embodiment, not shown in FIG. 1, the defining device 112 has a low-pass filter and a high-pass filter. The defining device 112 is, in one exemplary embodiment, designed to filter the control signal 108 using a low-pass filter, in order to define the power switching signal 114 with low-frequency signal components of the control signal 108. Furthermore, the defining device 112 is designed to filter the control signal 108 using a high-pass filter, in order to define the communication signal 116 with high-frequency signal components of the control signal 108.

(13) In one exemplary embodiment, not shown, the power section 118 comprises a plurality of first switches 122 that can be controlled using the power switching signal 114. The first switches 122 are connected in parallel with one another between the first terminal 104 and the second terminal 106.

(14) The communication section 120 may have a plurality of second switches 124 that can be controlled using the communication signal 116. In this case the first switches 124 are connected in parallel with one another between the first terminal 104 and the second terminal 106.

(15) A number of the first switches 122 of the power section 118 is, in this case, larger than a number of the second switches 124 of the communication section 120.

(16) FIG. 2 shows a schematic representation of a power switch 100 according to one exemplary embodiment of the present invention. The power switch 100 has a control terminal 102, a first terminal 104 and a second terminal 106. A housing 226 encloses the devices of the power switch 100.

(17) The control terminal 102 is also referred to as a gate terminal 102. The first terminal 104 is also referred to as a drain terminal 104, a collector 104 or a collector terminal 104. Additionally, the second terminal 106 is also referred as a source terminal 106, an emitter 106 or an emitter terminal 106.

(18) The power switch 100 shown in FIG. 2 may be an exemplary embodiment of a power switch 100 as shown in FIG. 1, arranged in a housing. In one variant, the power switch 100 is a semiconductor component that is designed to switch electric current of more than 100 amps and voltage of more than 1000 volts. In this case the power switch provides data communication superposed on the power signal.

(19) FIG. 3 shows a block diagram of a power switch 300 for a battery system. The power switch 300 has a control terminal 102, a first terminal 104, a second terminal 106 and four switches 322 or four individual switches 322.

(20) The exemplary embodiment shown in FIG. 3 shows a typical arrangement of the individual switches 322, wherein a parallel arrangement of many individual switches 322 (typically transistors 322) is represented. The parallel connection of a number N of these individual switches 322 makes it possible for the power switch 300 to achieve a current-carrying capacity of approximately N times that of the individual switch 322.

(21) For a power switch 300, also referred to as a transistor 300, the total current-carrying capacity I.sub.ges is approximately the sum of the individual current-carrying capacities I.sub.einzel of all N transistors 322:
I.sub.gesN*T.sub.einzel(1)

(22) The frequency response of a transistor 300 is substantially determined by the value of the input capacitance C.sub.G at the control input 102. In this case the time constant T.sub.G is calculated from the product of C.sub.G and the supply lead resistance R.sub.G:
T.sub.G=C.sub.G*R.sub.G(2)

(23) When the individual transistors 322 are connected in parallel to form an aggregate transistor 300, the respective individual input capacitances C.sub.G einzel are added together to give the total input capacitance C.sub.G_ges:
C.sub.G ges=C.sub.G einzel*N(3)

(24) Thus, according to equations (2) and (3), the total time constant T.sub.G_ges is given by:
T.sub.G ges=C.sub.G einzelN*R.sub.G(4)

(25) Due to the sum of the individual capacitances C.sub.G_einzel, T.sub.G_ges is thus greater by a factor N in comparison with an individual transistor 322 and is thus also slower by this factor in terms of switching response.

(26) FIG. 4 shows a block diagram of a power switch 100 for a battery system according to one exemplary embodiment of the present invention. The power switch 100 may be an exemplary embodiment of a power switch 100 as shown in FIG. 1, wherein the power section 118 comprises a number Nn of first switches 122 and the communication section 120 comprises a number n of second switches 124. In FIG. 4, only two first switches 122 are shown for the power section 118 from a number Nn of first switches 122. The communication section 120 has two second switches 124. In one favorable exemplary embodiment, the number of first switches 122 of the power section 118 is larger than the number of second switches 124 of the communication section 120 by, for example, a factor of at least 100.

(27) The power switch 100 additionally has a control terminal 102 for receiving a control signal 108. Furthermore, the power switch 100 has a first terminal 104 and a second terminal 106. The control terminal 102 is connected to a defining device 112. The defining device 112 comprises a low-pass filter 430 and a high-pass filter 432. The low-pass filter 430 is designed to define a power signal 114 using the control signal 108. The high-pass filter 432 is designed to define a communication signal 116 using the control signal 108. The first switches 122 of the power section 118 and the second switches 124 of the communication section 120 are parallel-connected between the first terminal 104 and the second terminal 106.

(28) In one exemplary embodiment, the low-pass filter 430 defines the power signal 114 in response to the control signal 108. The high-pass filter 432 defines the communication signal 116 in response to the control signal 108.

(29) One output 434 of the low-pass filter 430 is connected to a control terminal 438 of the first switches 122 of the power section 118 via a first signal line 436, or low-frequency signal line 436. One output 440 of the high-pass filter 432 is connected to a control terminal 444 of the second switches 124 of the communication section 120 via a second signal line 442, or high-frequency signal line 442. Between the control terminal 438 of the first switches 122 of the power section 118 and the second terminal 106, a respective capacitance C.sub.G_NF is arranged and electrically connected to said terminals. Between the control terminal 444 of the second switches 124 of the communication section 120 and the second terminal 106, a respective capacitance C.sub.G_HF is arranged and electrically connected to said terminals.

(30) The power switch 100 shown in FIG. 4 is structurally similar to the power switch 300 shown in FIG. 3. Both the power switch 300 shown in FIG. 3 and the power switch 100 shown in FIG. 4 have a number N of switches 322 (FIG. 3) or a total number N of first switches 122 and second switches 124 (FIG. 4). In FIG. 3, the control signal 108 present on the control input 102 is routed directly to the switches 322, whereas in FIG. 4 a power signal 114 and a communication signal 116 are defined from the control signal 108 in the defining device 112, and the power signal 114 is routed to the first switches 122 of the power section 118 and the communication signal 116 is routed to the second switches 124 of the communication section 120.

(31) From among the number N of first and second switches 122, 124, a markedly smaller number n of the second switches 124 is separately connected to the control terminal 102 in order to be used for the switching operations of the high-frequency signal component. This therefore results in the current-carrying capacity of the aggregate transistor I.sub.ges being divided into a low-frequency component I.sub.NF, which is switched via a number Nn of first switches 122, and a high-frequency component I.sub.HF, which is switched via a number n of second switches 124:
I.sub.ges=I.sub.NF+I.sub.HF=I.sub.einzel*(Nn)+I.sub.einzel*n(5)

(32) Since n<<N, that is to say that the number n of second switches 124 is substantially smaller than the number N of first switches 122, is presupposed, then the current-carrying capacity I.sub.NF in the low-frequency range may be considered to be virtually unaffected, i.e. I.sub.ges corresponds approximately to I.sub.NF and the time constant T.sub.G_NF of the transistor capacitances C.sub.G_NF connected to the low-frequency signal line 436 also corresponds approximately to the time constant T.sub.G.
T.sub.G_NF=C.sub.G_NF*(Nn)(6)

(33) In contrast thereto, for the second switches connected to the high-frequency signal line 442, a current-carrying capacity I.sub.HF is found:
I.sub.HF=I.sub.einzel*n(7)

(34) Thus, I.sub.HF<<I.sub.ges. However, since at high frequency only communication signals 116 whose power is markedly lower than on the low-frequency pathway are transmitted, this limitation presents no disadvantage.

(35) Advantageously, the resulting time constant T.sub.G_HF of the high-frequency signal pathway is given by:
T.sub.G_HF=C.sub.G_einzel*n*R.sub.G(8)

(36) This time constant T.sub.G_HF is smaller than that of the aggregate power switch T.sub.G shown in FIG. 3, that is to say power switch 300, by a factor N/n. Thus, a substantial decrease in the transient duration of switchover may be achieved and thus this power switch 100 is also suitable for the transmission of high-frequency signal components. In terms of control of the power switches 100, there is no difference in comparison with previous systems (no conversion costs), since furthermore only one control terminal 102 is present and the signal splitting of the superposed high and low frequencies of the control signal 108 into the power signal 114 and the communication signal 116 is carried out in the power semiconductor component 100 or in the defining device 112 inside the power switch 100. The combination of optimized switching response for both low-frequency power signals 114 and high-frequency data signals 116 represents a marked improvement in the prior art and may, for example, be used for traction batteries in electric vehicles for the simultaneous switching of inverter currents and communication signals to modules or battery cells.

(37) Advantageously, dividing the switches 122, 124 into a power section 118 and a communication section 120 improves a temporal response of a power transistor 100 for the switching of high-frequency signals.

(38) FIG. 5 shows a simplified representation of normalized signals 108, 114, 116 of a power switch. In a stacked illustration, a control signal 108, a power signal 114 and a communication signal 116 are shown. The forementioned signals 108, 114, 116 are each shown in a Cartesian coordinate system with a normalized amplitude along the ordinate and in normalized time units along the abscissa. The control signal 108 may also be referred to as a gate control signal 108. The power signal 114 may also be referred to as a low-frequency power switching signal 114. The communication signal 116 may be understood to be a high-frequency communication signal 116. The signals 108, 114, 116 are alternating signals. In this case the control signal 108 has three different signal levels and the power signal 114 and the communication signal 116 have two different signal levels. The period duration of the signals has been chosen arbitrarily for the representation in FIG. 5. In this case the representation of the power signal 114 shows a low-frequency signal and the representation of the communication signal 116 shows a high-frequency signal. In the exemplary embodiment shown, the control signal 108 corresponds to the sum of the power signal 114 and the communication signal 116.

(39) FIG. 6 shows a flowchart of a method for operating a power switch for superposed data communication for a battery system according to one exemplary embodiment of the present invention. The power switch may, for example, be an exemplary embodiment of a power switch 100 as shown in FIG. 1 or FIG. 4. The method comprises a step 602 of defining a power switching signal and a communication signal using a control signal present on the control terminal of the power switch, a step 604 of using the power switching signal to switch an electrical connection between the first terminal and the second terminal using at least one first switch of the power section and a step 606 of using the communication signal to switch an electrical connection between the first terminal and the second terminal using at least one second switch of the communication section.

(40) In one exemplary embodiment, in usage step 604, the power section of the power switch is controlled using the power switching signal, in order to switch an electrical connection between the first terminal and the second terminal, and in usage step 606, the communication section of the power switch is controlled using the communication signal, in order to switch the electrical connection between the first terminal and the second terminal. In this case, in step 604, the first switches are controlled in the power section and in step 606, the second switches are controlled in the communication section, in order to switch the electrical connection.

(41) Control steps 604, 606 are typically carried out in parallel with one another, but can also be carried out sequentially.

(42) In one optional exemplary embodiment, in defining step 602, the power switching signal and the communication signal are defined using a signal processing rule. In this case the at least one signal processing rule and the control signal are used to define the power switching signal with low-frequency signal components of the control signal and the communication signal with high-frequency signal components of the control signal.

(43) One aspect of the method described in FIG. 6 is that an electrical switch, typically a power semiconductor, which is manufactured as a component, possesses both characteristics for switching high currentsof several hundreds of amps in the case of electric vehiclesand characteristics for switching high-frequency communication signals. Advantageously, battery cells or battery modules with integrated power electronics (inverters at module level or cell level) can exchange measurement data and control data between cells or modules and the central control unit without additional communication drivers.

(44) FIG. 7 show a schematic representation of a battery system 750 according to one exemplary embodiment of the present invention. The battery system 750 may be a Li-ion battery 750. In the embodiment shown, the battery system 750 comprises a control device 752, a battery module 754, each with a power switch 100, two battery cells 756 and, for example, a sensor 757.

(45) The control device 752 is connected to the control terminal 102 of the power switch 100 via a control line 758. The battery system 750 has a first terminal 760 and a second terminal 762. The first terminal 760 is connected to a first terminal of the power switch 100. The second terminal of the power switch 100 is connected to first terminals of the battery cells 756 and to a communication terminal of the sensor 757. Second terminals of the battery cells 756 are connected to the second terminal 762 of the battery system 750.

(46) In one exemplary embodiment, the power switches 100, also referred to as power transistors 100, have an optimized switching response for superposed data communication for example on Li-ion batteries.

(47) The power switches 100 represented in the exemplary embodiment shown in FIG. 7 are additionally used as communication drivers. It is advantageous, when using the described module- or cell-integrated power switches 100 as communication drivers, that the switching response (rise times, input capacitances, etc.) is adapted to both the communication frequencies and the frequencies of the power switches/inverter frequencies (typically 1 kHz to 10 kHz), which are typically markedly lower in relation to the communication frequencies (typically>>100 kHz).

(48) The exemplary embodiments described and shown in the figures have been chosen only by way of example. Various exemplary embodiments may be combined with one another as a whole or with reference to individual features. It is also possible for an exemplary embodiment to have features from a further exemplary embodiment added thereto. Additionally, the method steps presented here may be repeated and carried out in an order other than that described.

(49) If an exemplary embodiment comprises an and/or conjunction between a first feature and a second feature, this is intended to be read to mean that the exemplary embodiment has both the first feature and the second feature in accordance with one embodiment and has either just the first feature or just the second feature in accordance with a further embodiment.