Abstract
A circuit arrangement (11) for supplying an electric vehicle with power comprises a battery (10) with a first terminal (16) and a second terminal (17), and a reference potential terminal (12) directly connected to the second terminal (17) of the battery (10). The circuit arrangement (11) further comprises a first output (18) that is coupled to the first terminal (16) of the battery (10) via a first switch (20) and that is configured to be connected to an electric machine (33) of the electric vehicle, and a second output (19) that is coupled to the first terminal (16) of the battery (10) and that is configured to be connected to a power net (34) of the electric vehicle. Furthermore, a power system (32) for an electric vehicle comprises the circuit arrangement (11), an electric machine (33) and a power net (34). The first output (18) is coupled to the electric machine (33) and the second output (19) is coupled to the power net (34).
Claims
1. A circuit arrangement for supplying an electric vehicle with power, the circuit arrangement comprising: a battery with a first terminal and a second terminal, a reference potential terminal directly connected to the second terminal of the battery, a first output that is coupled to the first terminal of the battery via a first switch and that is configured to be connected to an electric machine of the electric vehicle, a second output that is directly and permanently coupled to the first terminal of the battery and that is configured to be connected to a power net of the electric vehicle, and the battery is configured to supply both the electric machine which is a main traction motor of the electric vehicle and the power net of the electric vehicle with power; wherein a battery voltage which can be tapped between the first terminal and the second terminal of the battery is at most 60 V.
2. The circuit arrangement according to claim 1, where the electric vehicle is at least one of: a craft that can move on ground, a craft that can move in the air, a craft that can move on and/or in water.
3. The circuit arrangement according to claim 1, where the first switch comprises at least two sub-switches arranged in at least two parallel lines where the parallel lines are connected with each other by an inductive connection which comprises at least one inductivity.
4. The circuit arrangement according to claim 1, where the first terminal and the second terminal of the battery are coplanar or coaxial.
5. The circuit arrangement according to claim 1, where the first terminal and/or the second terminal of the battery comprise at least two contacts, respectively.
6. The circuit arrangement according to claim 1, where the battery comprises at least one line of battery cells, where a first group comprises a plurality of battery cells connected to each other in parallel, a second group comprises a plurality of battery cells connected to each other in parallel, and the first group and the second group are connected with each other in series forming the line of battery cells.
7. The circuit arrangement according to claim 6, where the line is connected to at least one further line in parallel, where the further line comprises the same features as the line, and a fuse is connected to a circuit node of the line and to a circuit node of the further line.
8. The circuit arrangement according to claim 7, where the fuse is a positive temperature coefficient thermistor.
9. The circuit arrangement according to claim 1, where the battery comprises at least two battery modules.
10. The circuit arrangement according to claim 9, where the at least two battery modules are configured to be electrically coupled to the electric machine of the electric vehicle.
11. The circuit arrangement according to claim 9, where the at least two battery modules are arranged in parallel and each battery module is assigned a respective switch to activate and/or deactivate the respective battery module.
12. A power system for an electric vehicle, the power system comprising: a circuit arrangement comprising: a battery with a first terminal and a second terminal, a reference potential terminal directly connected to the second terminal of the battery, a first output that is coupled to the first terminal of the battery via a first switch and that is configured to be connected to an electric machine of the electric vehicle, a second output that is directly and permanently coupled to the first terminal of the battery and that is configured to be connected to a power net of the electric vehicle, and the battery is configured to supply both the electric machine which is a main traction motor of the electric vehicle and the power net of the electric vehicle with power; wherein a battery voltage which can be tapped between the first terminal and the second terminal of the battery is at most 60 V.
13. The power system according to claim 12, where the electric machine and the power net are supplied with a same voltage level by the battery.
14. The power system according to claim 12, where the electric machine is only powered by the battery.
15. A circuit arrangement for supplying an electric vehicle with power, the circuit arrangement comprising: a battery with a first terminal and a second terminal, a reference potential terminal directly connected to the second terminal of the battery, a first output that is coupled to the first terminal of the battery via a first switch and that is configured to be connected to an electric machine of the electric vehicle, and a second output that is directly and permanently coupled to the first terminal of the battery and that is configured to be connected to a power net of the electric vehicle, wherein the battery comprises at least one line of battery cells, where a first group comprises a plurality of battery cells connected to each other in parallel, a second group comprises a plurality of battery cells connected to each other in parallel, and the first group and the second group are connected with each other in series forming the line of battery cells, and wherein a battery voltage which can be tapped between the first terminal and the second terminal of the battery is at most 60 V.
Description
(1) In FIGS. 1A, 1B and 1C different embodiments of the circuit arrangement are shown.
(2) In FIG. 2 an embodiment of the first switch is shown.
(3) In FIGS. 3A, 3B, 3C, 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4I, 5A, 5B, 6A and 6B electrical contacts of the battery are shown.
(4) In FIG. 7A a first group and a second group of battery cells are shown.
(5) In FIGS. 7B and 8 four lines of battery cells are shown.
(6) In FIGS. 9A and 9B two battery modules are depicted.
(7) FIG. 10 shows an electrical circuit with battery modules connected to each other in parallel.
(8) In FIG. 11 battery cells connected to the electric machine are shown.
(9) With FIGS. 12A, 12B and 13 fuses for battery cells are described.
(10) In FIG. 14 an embodiment of the power system is shown.
(11) In FIG. 1A an embodiment of a circuit arrangement 11 for supplying an electric vehicle with power is shown. The circuit arrangement 11 comprises a battery 10 with a first terminal 16 and a second terminal 17. The first terminal 16 and the second terminal 17 can be electrical contacts where the battery 10 can be electrically contacted and where a load can be connected. The second terminal 17 of the battery 10 is directly connected to a reference potential terminal 12. The battery voltage is given in relation to the reference potential. The reference potential terminal 12 is connected to a further reference potential terminal 12.
(12) The first terminal 16 of the battery 10 is coupled to a first output 18 via a first switch 20. In this embodiment the first switch 20 is a semiconductor switch. The first output 18 is configured to be connected to an electric machine 33 of the electric vehicle. A second output 19 is coupled to the first terminal 16 of the battery 10 via an electric line or an electric cable. The second output 19 is configured to be connected to a power net 34 of the electric vehicle.
(13) Electric lines or cables crossing each other in the figures are electrically isolated against each other. Electric lines or cables which are connected with a connection point in the figures are electrically connected with each other.
(14) That the first output 18 is configured to be connected to an electric machine 33 of the electric vehicle means that the first output 18 can be electrically connected with the electric machine 33. If for example the electric machine 33 comprises an electrical contact the first output 18 can be electrically connected with the electrical contact of the electric machine 33. Preferably, the first output 18 is configured to be connected to the electric machine 33 in such a way that the electric machine 33 can be supplied with power by the battery 10.
(15) That the second output 19 is configured to be connected to the power net 34 of the electric vehicle means that the second output 19 can be electrically connected with the power net 34. If for example the power net 34 comprises an electrical contact the second output 19 can be electrically connected with the electrical contact of the power net 34. Preferably, the second output 19 is configured to be connected to the power net 34 in such a way that the power net 34 can be supplied with power by the battery 10.
(16) The battery 10 is configured to supply both the electric machine 33 and the power net 34 of the electric vehicle with power. Consequently, only one battery 10 is required for the electric vehicle.
(17) In FIG. 1B a further embodiment of the circuit arrangement 11 is shown. In this embodiment the second output 19 is coupled to the first terminal 16 of the battery 10 via a second switch 23. The second switch 23 is a semiconductor switch. It is also possible that the second switch 23 is any other type of switch. The first switch 20 is an electro-mechanical switch. It is also possible that the first switch 20 is any other type of switch.
(18) In FIG. 1C a further embodiment of the circuit arrangement 11 is shown. In this embodiment the second switch 23 is a DC/DC converter. Advantageously, with a DC/DC converter the second output 19 can be completely decoupled from the battery 10 and the first output 18.
(19) In FIG. 2 an embodiment of the first switch 20 is shown. The first switch 20 comprises three sub-switches 30 that are connected with each other in parallel. Thus, the three sub-switches 30 are arranged in three parallel lines where the parallel lines are connected with each other by an inductive connection which comprises an inductivity 31, respectively. The sub-switches 30 can be mechanical or electro-mechanical switches or semiconductor switches. The inductive connection is an electrical connection between the three lines. That the inductive connections comprise an inductivity 31 means that the three lines are connected with each other via the inductivity 31. The inductivity 31 comprises an inductor as for example a coil.
(20) The sub-switches 30 of the first switch 20 are usually opened with small time delays. In order to avoid that the current from the battery 10 towards the first output 18 only flows through the sub-switch 30 which is opened at last the inductivities 31 allow compensation currents between the sub-switches 30 and avoid rapidly rising currents in the first switch 20.
(21) In FIG. 3A a battery 10 with a first terminal 16 and a second terminal 17 is shown. The first terminal 16 and the second terminal 17 are arranged at a side surface of the battery 10. The first terminal 16 comprises two contacts 21 which are marked hatched. The second terminal 17 comprises one contact 21 which is marked solid. The contacts 21 of the first terminal 16 and of the second terminal 17 have the same shape. The first terminal 16 and the second terminal 17 are coplanar. Advantageously, the first terminal 16 and the second terminal 17 are coplanar in order to reduce the extent of the magnetic field induced by the current flowing through the terminals 16, 17.
(22) In FIG. 3B an alternative to arrange the first terminal 16 and the second terminal 17 at a side surface of the battery 10 is shown. Both terminals 16, 17 comprise three contacts 21. A contact 21 of the first terminal 16 is arranged between two contacts 21 of the second terminal 17 in a coplanar arrangement. Moreover, a contact 21 of the second terminal 17 is arranged between two contacts 21 of the first terminal 16 in a coplanar arrangement.
(23) In FIG. 3C an alternative to arrange the first terminal 16 and the second terminal 17 at a side surface of the battery 10 is shown. The battery 10 comprises the same contacts 21 as shown in FIG. 10B and furthermore two contacts 21 at a further side surface of the battery 10. At the further side surface a contact 21 of the first terminal 16 and a contact 21 of the second terminal 17 are arranged next to each other in a coplanar arrangement. As the battery voltage is small, the currents at the first terminal 16 and at the second terminal 17 can be high. Therefore, it is advantageous to distribute the current over several electrical contacts 21.
(24) In FIGS. 4A to 4I nine alternatives to arrange the first terminal 16 and the second terminal 17 at a side surface of the battery 10 are shown. The contacts 21 of the first terminal 16 are marked hatched and the contacts 21 of the second terminal 17 are marked solid. In all embodiments the terminals 16, 17 are arranged coplanar or coaxial in order to reduce the extent of the magnetic field induced by the current flowing through the terminals 16, 17.
(25) In FIG. 4A the first terminal 16 comprises one contact 21 and the second terminal 17 comprises two contacts 21. All contacts 21 are rectangular shaped and arranged coplanar. The first terminal 16 is arranged between the two contacts 21 of the second terminal 17.
(26) In FIG. 4B the first terminal 16 and the second terminal 17 each comprise three contacts 21. A first contact 21 of the first terminal 16 is circular shaped. The first contact 21 of the first terminal 16 is surrounded by a ring-shaped contact 21 of the second terminal 17. A second contact 21 of the second terminal 17 is circular shaped. The second contact 21 of the second terminal 17 is surrounded by a ring-shaped contact 21 of the first terminal 16. A third contact 21 of the first terminal 16 is circular shaped. The third contact 21 of the first terminal 16 is surrounded by a ring-shaped contact 21 of the second terminal 17.
(27) In FIG. 4C the first terminal 16 comprises eight contacts 21 and the second terminal 17 comprises one contact 21. All contacts 21 are rectangular shaped. The contacts 21 of the first terminal 16 are coaxially arranged around the second terminal 17.
(28) In FIG. 4D the first terminal 16 comprises seven contacts 21 and the second terminal 17 comprises eight contacts 21. All contacts 21 are circular shaped. The contacts 21 of both terminals 16, 17 are arranged in an alternating structure, this means in a checkerboard structure.
(29) In FIG. 4E the first terminal 16 comprises eight contacts 21 and the second terminal 17 comprises two contacts 21. All contacts 21 are rectangular shaped. The contacts 21 of the first terminal 16 are coaxially arranged around the contacts 21 of the second terminal 17.
(30) In FIG. 4F the first terminal 16 comprises six contacts 21 and the second terminal 17 comprises one contact 21. All contacts 21 are rectangular shaped. The two terminals 16, 17 are arranged coplanar and the second terminal 17 is arranged between the contacts 21 of the first terminal 16.
(31) In FIG. 4G the first terminal 16 and the second terminal 17 each comprise one contact 21. The first terminal 16 is rectangular shaped. The second terminal 17 is arranged as a stripe that surrounds the first terminal 16.
(32) In FIG. 4H the first terminal 16 comprises five contacts 21 and the second terminal 17 comprises one contact 21. The contacts 21 of the first terminal 16 are circular shaped and are arranged along a line at the side surface of the battery 10. The second terminal 17 is arranged as a stripe that surrounds the contacts 21 of the first terminal 16.
(33) In FIG. 4I the first terminal 16 comprises five contacts 21 and the second terminal 17 comprises eight contacts 21. The contacts 21 of the first terminal 16 are circular shaped and are arranged along a line at the side surface of the battery 10. The contacts 21 of the second terminal 17 are rectangular shaped and coaxially arranged around the contacts 21 of the first terminal 16.
(34) In FIG. 5A a side view of the battery 10 with the first terminal 16 and the second terminal 17 is shown. The contacts 21 of the first terminal 16 and the second terminal 17 are arranged as plugs.
(35) In FIG. 5B a side view of the battery 10 with the first terminal 16 and the second terminal 17 is shown. The contacts 21 of the first terminal 16 and the second terminal 17 are arranged as sockets.
(36) In FIG. 6A another alternative to arrange the first terminal 16 and the second terminal 17 at a side surface of the battery 10 is shown. The first terminal 16 comprises several contacts 21 and the second terminal 17 comprises one contact 21. The contacts 21 of the first terminal 16 are arranged coaxially around the contact 21 of the second terminal 17. The two terminals 16, 17 are electrically isolated against each other. A clamp 27 is arranged around the terminals 16, 17 in order to induce force on an external terminal which can be connected to the battery 10. The induced force is indicated by the arrows. In this way the contact between the two terminals 16, 17 and the external terminal is improved and the contact resistance is decreased.
(37) In FIG. 6B another alternative to arrange the first terminal 16 and the second terminal 17 at a side surface of the battery 10 is shown. The only difference to the embodiment shown in FIG. 13A is that the external terminal can be fixed to the terminals 16, 17 of the battery 10 by screws 28.
(38) In FIG. 7A a plurality of battery cells 13 of a battery 10 for an electric vehicle is shown. A first group 36 comprises four battery cells 13 connected to each other in parallel. A second group 37 also comprises four battery cells 13 connected to each other in parallel. The first group 36 and the second group 37 are connected with each other in series forming a line 14. It is possible that further groups comprising battery cells 13 are connected in series with the first group 36 and the second group 37. The battery cells 13 can be for example lithium ion batteries with rated battery voltages between 3 and 4 V.
(39) The number of groups connected to each other in series can be kept small enough such that the battery voltage does not exceed a desired value and at the same time the capacity of the battery 10 is as high as required for an electric vehicle. The battery voltage can for example be at least 6 V and at most 60 V.
(40) In FIG. 7B four lines of battery cells 13 of a battery 10 for an electric vehicle are shown. A line 14 comprises a first group 36 and a second group 37 connected to each other in series. Three further lines 15 also comprises a first group 36 and a second group 37 connected to each other in series. The line 14 is connected to the further lines 15 in parallel.
(41) The number of groups 36, 37 connected in series to each other in each line can be kept small enough such that the battery voltage does not exceed a desired value and at the same time the capacity of the battery 10 is as high as required for an electric vehicle.
(42) In FIG. 8 four lines are connected to each other in parallel. Each line comprises at least a first group 36 and a second group 37 of battery cells 13. A fuse 24 is connected to a circuit node of a line 14 and to a circuit node of a further line 15. Two further fuses 24 are connected to further circuit nodes of the line 14 and of the further line 15, respectively. In this way, the line currents I.sub.1 in the different lines can be regulated such that all line currents I.sub.1 are the same. Furthermore, if for example a battery cell 13 or a group 36, 37 of battery cells 13 in the line 14 is defective a high line current I.sub.1 can arise in the line 14. With the fuses 24 it is avoided that the high line current I.sub.1 also flows through further lines 15. The fuses 24 can for example be realized as shown in FIG. 8 or as positive temperature coefficient thermistors.
(43) In FIG. 9A two battery modules 22 are shown. Each battery module 22 comprises two lines 14, 15 each comprising two groups 36, 37 of battery cells 13. The line 14 and the further lines 15 are connected with each other in parallel by an electric line which can be for example an electric cable. Moreover, the two battery modules 22 are connected with each other in parallel.
(44) By distributing the groups 36, 37 of battery cells 13 to the different battery modules 22 it is possible to arrange the different battery modules 22 at different places in the electric vehicle. Therefore, all places in the vehicle where there is space for battery modules 22 can be used.
(45) In FIG. 9B two battery modules 22 and four lines 14, 15 are shown. Each line 14, 15 is distributed over the two battery modules 22. This means, a first group 36 of for example the line 14 is arranged in one battery module 22 and the second group 37 of the line 14 is arranged in the other battery module 22. The groups 36, 37 of each line are connected in series with each other. The four lines 14, 15 are connected to each other in parallel.
(46) If all lines of the battery 10 are comprised by at least two battery modules 22 temperature differences between the battery modules 22 and different contact resistances of different battery modules 22 are experienced by all lines in the same way. Therefore, differences in capacity or voltage of the lines due to external parameters as the temperature or contact resistances of the battery modules 22 are avoided.
(47) FIG. 10 shows an electrical circuit with four battery modules 22 connected to each other in parallel. Three of the battery modules 22 can be disconnected from the other battery modules 22 by a switch 35 which is connected in series with the respective battery module 22. This means, each of these battery modules 22 is assigned a respective switch 35 to activate and/or deactivate the respective battery module 22. The first switch 35 on the left-hand side of the electrical circuit is a DC/DC converter. The second switch 35 is a mechanical switch and the third switch 35 is a semiconductor switch. The fourth battery module 22 cannot be disconnected by a respective switch 35. It is also possible that further battery modules 22 are connected to the four battery modules 22 in parallel.
(48) In FIG. 11 groups 36, 37 of battery cells 13 connected to the electric machine 33 of the electric vehicle are shown. The groups 36, 37 can be comprised by different battery modules 22 which are not shown. The groups 36, 37 are arranged in four different lines where each line comprises a first group 36 and a second group 37. The electric machine 33 comprises different electrical phases φ. The electrical phases φ can each be supplied with a respective phase current. The phase currents comprise an AC and a DC component. Each line is connected to two or more electrical phases φ of the electric machine 33. The electrical phases φ are short-circuited on a short circuit ring 29 of the electric machine 30. Therefore, the line currents I.sub.1 are equalized if the groups 36, 37 of battery cells 13 are connected with the electrical phases φ.
(49) This means, the electric machine 33 is employed to equalize the line currents I.sub.1 of the different lines of battery cells 13. As the electric machine 33 is controlled by the AC components of the phase currents the regulation of the line currents I.sub.1 can take place both when the electric machine 33 is operated and when it is not operated.
(50) In order to exchange battery modules 22, switches 35 are arranged between the lines. If single battery modules 22 can be exchanged and be replaced by charged battery modules 22 the charging level of the charged battery modules 22 and the battery modules 22 which are not replaced can be very different. This means, high compensation currents can arise. By regulating the line currents I.sub.1 by coupling the battery modules 22 to the electric machine 33 the losses during regulation of the line currents I.sub.1 are smaller in comparison to losses during a regulation of the line currents I.sub.1 by passive elements as for example a positive temperature coefficient thermistor.
(51) In FIG. 12A a battery cell 13 with an electrical contact 21 is shown. The electrical contact 21 is a contact comprising a screw. The electrical contact 21 of the battery cell 13 is connected to a metal sheet 25. The metal sheet 25 can comprise aluminum or copper and it can connect several battery cells 13 with each other in parallel. The metal sheet 25 comprises a circular shaped hole around the electrical contact 21 except for two connections 26. The connections 26 act as fuses 24. If the current flowing from the battery cell 13 towards the metal sheet 25 is too high the two connections 26 will warm up and melt. For a better stability against for example torque exerted on the electrical contact 21 the metal sheet 25 comprises two connections 26 instead of only one.
(52) In FIG. 12B a battery cell 13 with an electrical contact 21 which is a welding contact is shown. In this case the metal sheet 25 only comprises one connection 26 as a fuse 24 since no torque is exerted on the electrical contact 21.
(53) In FIG. 13 six battery cells 13 which are connected with metal sheets 25 are shown. Three battery cells 13 are connected with a metal sheet 25 on a top side of the battery cells 13 and with another metal sheet 25 on a bottom side of the battery cells 13 facing away from the top side. Three further battery cells 13 are also connected with a metal sheet 25 on the top side and with another metal sheet 25 on the bottom side of the battery cells 13. The two metal sheets 25 on the top side of the battery cells 13 are connected with each other by two thin connections 26. Similarly, the two metal sheets 25 on the bottom side of the battery cells 13 are connected with each other by two thin connections 26. The connections 26 act as fuses 24 as described with FIG. 12A.
(54) In FIG. 14 an embodiment of the power system 32 is shown. The power system 32 comprises a circuit arrangement 11 as described above. The power system 32 further comprises an electric machine 33 and a power net 34, where the first output 18 is electrically coupled to the electric machine 33 and the second output 19 is electrically coupled to the power net 34. This means, the battery 10 is configured to supply both the electric machine 33 and the power net 34 of the electric vehicle with power. Consequently, only one battery 10 is required for the electric vehicle.
(55) The power system 32 can be comprised by an electric vehicle. The power system is arranged to supply the electric vehicle with power, to enable movement of the electric vehicle and to enable the operation of the devices of the power net 34.
(56) Advantageously, the electric machine 33 and the power net 34 are supplied with the same voltage level by the battery 10, as neither between the first terminal 16 of the battery 10 and the first output 18 nor between the first terminal 16 and the second output 19 converters are arranged.
LIST OF REFERENCE NUMERALS
(57) 10: battery 11: circuit arrangement 12: reference potential terminal 13: battery cell 14: line 15: further line 16: first terminal 17: second terminal 18: first output 19: second output 20: first switch 21: contact 22: battery module 23: second switch 24: fuse 25: metal sheet 26: connection 27: clamp 28: screw 29: short circuit ring 30: sub-switch 31: inductivity 32: power system 33: electric machine 34: power net 35: switch 36: first group 37: second group I.sub.1: line current φ: electrical phase
