Device and method for controlling a charging process of an electrical energy store of a vehicle

Abstract

The invention relates to a device (250) for controlling a charging process of an electrical energy store (110) of a vehicle (100) at a charging station (120) that is external to the vehicle, wherein the energy store (110) comprises a first sub-store (201) and a second sub-store (202). The device (250) is designed to charge the energy store (110) with a serial arrangement of the first sub-store (201) and the second sub-store (202) in a first phase of the charging process. The device (250) is also designed to effect a switch-over process in which the first sub-store (201) and the second sub-store (202) are transferred out of the serial arrangement into a parallel arrangement, and to charge the energy store (110) with the parallel arrangement in a second phase of the charging process.

Description

[0001] Device and method for controlling a charging process of an electrical energy storage device of a vehicle

[0002] The invention relates to a device and a corresponding method for controlling a charging process of an electrical energy storage device of a (motor) vehicle.

[0003] An electric vehicle (in particular an electric vehicle or a plug-in hybrid vehicle) comprises an electrical energy storage device that can be connected to an external charging station via a charging interface of the vehicle and charged. Different charging stations can have different charging voltages for charging the electrical energy storage device. In particular, a charging station may have a charging voltage that is below the nominal voltage of the electrical energy storage device. This can lead to the vehicle's energy storage device not being fully charged. This document addresses the technical task of enabling the fastest possible charging process to fully charge a vehicle's electrical energy storage device.

[0004] The problem is solved in each case by the independent claims. Advantageous embodiments are described, among other things, in the dependent claims. It should be noted that additional features of a patent claim dependent on an independent patent claim can form a separate invention, independent of the combination of all features of the independent patent claim, without the features of the independent patent claim or only in combination with a subset of the features of the independent patent claim, which invention can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can form an invention independent of the features of the independent patent claims.

[0005] According to one aspect, a device for controlling a charging process of an electrical energy storage device (in particular an electrochemical energy storage device) of a (motor) vehicle at a vehicle-external charging station is described. The energy storage device can be electrically connected to the vehicle-external charging station via a charging cable for the charging process.

[0006] The energy storage device comprises a first storage sub-device and a second storage sub-device, which can be arranged in a serial arrangement (by means of one or more switching elements, such as semiconductor-based switching elements or relays), in which the first storage sub-device and the second storage sub-device are connected in series. The first storage sub-device and the second storage sub-device can each have a nominal voltage (e.g., 300V or more). In the serial arrangement, the energy storage device can have a total nominal voltage (e.g., 600V or more) that corresponds to the sum of the nominal voltages of the first storage sub-device and the second storage sub-device.

[0007] The first partial storage device and the second partial storage device can further be arranged (by means of one or more switching elements) in a parallel arrangement, in which the first partial storage device and the second partial storage device are arranged in parallel. In the parallel arrangement, the energy storage device can have a total nominal voltage that corresponds to the nominal voltage of the first partial storage device and / or the second partial storage device.

[0008] The device may be part of the vehicle, part of the charging station and / or part of a unit that is separate from the vehicle and the charging station.

[0009] The device is configured to charge the energy storage device with the serial arrangement of the first partial storage device and the second partial storage device in a first phase of the charging process. The device can be configured to cause the charging station to charge the energy storage device with a first charging voltage in the first phase of the charging process. The first charging voltage can be less than, e.g., 5% or more less than, the sum of the nominal voltages of the first partial storage device and the second partial storage device (i.e., the total nominal voltage of the energy storage device in the serial arrangement). On the other hand, the first nominal voltage can be greater than the nominal voltage of the first and / or the second partial storage device.

[0010] The use of a first charging voltage that is lower than the total nominal voltage of the energy storage device in the serial arrangement typically results in the energy storage device not being able to be fully charged. On the other hand, charging the energy storage device in the serial arrangement with a relatively high first charging voltage results in a relatively rapid charging process. The device is further configured to effect a switching process in which the first partial storage device and the second partial storage device are transferred from the serial arrangement to the parallel arrangement. The switching process can be effected in such a way that the charging process is not interrupted by the switching process and / or that the first partial storage device and the second partial storage device are transferred from the serial arrangement to the parallel arrangement during the ongoing charging process (in particular while electrical power is being provided by the charging station).

[0011] For this purpose, the device can be configured to cause one or more electrical consumers (of the vehicle) to create an electrical load for the charging station (in order to take the electrical power provided by the charging station) during the switching process. The electrical load for the charging station can be created instead of the load on the energy storage device caused by the charging process. The one or more electrical consumers can comprise an electric drive motor of the vehicle and / or an air conditioning system of the vehicle. The one or more electrical consumers can be designed for operating voltages that correspond to the first charging voltage (e.g., approximately 600V or more).

[0012] The device is further configured to charge the energy storage device with the parallel arrangement in a second phase of the charging process. The device can, in particular, be configured to cause the charging station to charge the energy storage device with a second charging voltage in the second phase of the charging process. The second charging voltage is typically lower than the first charging voltage. The second charging voltage can, in particular, be equal to or (if applicable) higher than the nominal voltage of the first partial storage device and / or the second partial storage device.

[0013] In a second phase of the charging process, the energy storage units can be charged with a reduced second charging voltage, which preferably corresponds at least to the nominal voltage of the energy storage units. This reliably ensures that the energy storage units are fully charged (e.g., up to a SOC (state of charge) of 100%).

[0014] The device is preferably configured to effect the switching process in such a way that the second phase of the charging process follows the first phase of the charging process without (manual) intervention (e.g., without intervention by a user of the vehicle and / or the charging station). This allows for a rapid and complete charging process of the energy storage device to be effected in a convenient manner.

[0015] As already explained above, the device can be configured to cause one or more electrical consumers (of the vehicle) to create an electrical load for the charging station during the switching process from the serial arrangement to the parallel arrangement (wherein the electrical load preferably corresponds to the electrical load of the energy storage device, e.g., at the end of the first phase of the charging process). The one or more electrical consumers can be caused to request a specific charging current (which corresponds, e.g., to the charging current during the first phase of the charging process). The charging current can be, for example, 1 A or more, in particular 5 A or more.

[0016] If (in particular as soon as) the electrical load is caused by the one or more electrical consumers, the first partial storage device and the second partial storage device can be decoupled from the charging station (without interrupting the charging process). The one or more electrical consumers can thus be used to provide a corresponding electrical load for the charging station instead of the (series-connected) partial storage devices (in order to take the electrical (charging) power provided by the charging station). This load is preferably only provided for a limited time for the switching process from the serial arrangement to the parallel arrangement of the energy storage device. In this way, an uninterrupted charging process with different charging voltages and with different arrangements of the partial storage devices can be enabled in a particularly reliable manner.

[0017] If (especially as soon as) the first partial storage unit and the second partial storage unit are decoupled from the charging station, the charging station can be instructed to reduce the charging voltage for the charging process from the first charging voltage to the second charging voltage. The electrical power of one or more electrical consumers is typically reduced accordingly. This allows for a particularly reliable switch from the serial arrangement to the parallel arrangement during an ongoing charging process.

[0018] The device can further be configured to couple the first partial storage device to the charging station during the switching process from the serial arrangement to the parallel arrangement, when (in particular as soon as) the charging voltage has been reduced to the second charging voltage. The first partial storage device then represents an electrical load for the charging station and can be charged by the charging station with the second charging voltage.

[0019] If, in particular, once the first partial storage device has been coupled to the charging station, the one or more electrical consumers can be prompted to no longer generate the electrical load for the charging station. In particular, the one or more electrical consumers can be prompted to request a load current of 0A. After at least the first partial storage device (and possibly the second partial storage device) has been arranged in parallel with the charging station, the temporary operation of the one or more electrical consumers can thus be terminated in order to continue the charging process of the electrical energy storage device in an energy-efficient manner.The device can further be configured to couple the second partial storage unit to the charging station in parallel with the first partial storage unit during the switching process from the serial arrangement to the parallel arrangement, when the electrical load is no longer caused by the one or more electrical consumers, in order to effect the parallel arrangement of the first partial storage unit and the second partial storage unit. If necessary, the second partial storage unit can be activated before or simultaneously with the deactivation of the one or more electrical consumers. The charging process can then be continued with the second phase in order to fully charge the first and / or second partial storage unit (up to an SOC of 100%).

[0020] The switching process from the serial arrangement to the parallel arrangement typically has a specific (relatively short) switching duration (e.g., 5 seconds or less). The operation of one or more electrical loads preferably occurs only during the switching duration of the switching process. Thus, a charging process can be carried out in an energy-efficient and robust manner with different arrangements of the energy storage sub-storage units.

[0021] The device can be configured to detect, during the first phase of the charging process, that the storage voltage at the electrical energy storage device (which typically corresponds to the vehicle's electrical system voltage) is equal to or greater than a predefined voltage threshold. The voltage threshold preferably depends on the first charging voltage. For example, the voltage threshold can be between 2% and 10% below the first charging voltage. In response to detecting that the voltage threshold has been reached or exceeded, the transition process can be initiated. By using a voltage threshold for the transition from the serial arrangement to the parallel arrangement, a particularly fast and reliable charging process can be achieved.According to a further aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described which comprises the device described in this document.

[0022] According to a further aspect, a method for controlling a charging process of an electrical energy storage device of a (motor) vehicle at a vehicle-external charging station is described. The energy storage device comprises a first partial storage device and a second partial storage device. In a first phase of the charging process, the method comprises charging the energy storage device with a serial arrangement of the first partial storage device and the second partial storage device. Furthermore, the method comprises effecting a switching process in which the first partial storage device and the second partial storage device are converted from the serial arrangement to a parallel arrangement. Furthermore, the method comprises charging the energy storage device with the parallel arrangement in a second phase of the charging process.

[0023] According to another aspect, a software (SW) program is described. The SW program can be configured to be executed on a processor (e.g., on a vehicle control unit) and thereby to carry out the method described in this document.

[0024] According to a further aspect, a storage medium is described. The storage medium can comprise a software program configured to be executed on a processor and thereby to carry out the method described in this document.

[0025] It should be noted that the methods, devices, and systems described in this document can be used both alone and in combination with other methods, devices, and systems described in this document. Furthermore, any aspects of the methods, devices, and systems described in this document can be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways. Furthermore, features listed in parentheses are to be understood as optional features.

[0026] The invention will be described in more detail below using exemplary embodiments.

[0027] Figure 1 is a block diagram of an exemplary charging system;

[0028] Figure 2a shows an exemplary charging system with a serial arrangement of the energy storage sub-storage units;

[0029] Figure 2b shows an exemplary charging system with a parallel arrangement of the energy storage sub-storage units;

[0030] Figure 3 shows an exemplary time profile of the voltage at the energy storage device during a charging process; and

[0031] Figure 4 is a flowchart of an exemplary method for controlling a charging process of an electrical energy storage device of a vehicle.

[0032] As stated at the beginning, this document deals with carrying out the fastest and most complete charging process possible for an electrical energy storage device of a vehicle. In this context, Fig. 1 shows a block diagram of an exemplary charging system with a (vehicle-external) charging station 120 and a vehicle 100. The vehicle 100 includes an electrical energy storage device 110 that can be charged with electrical energy from the charging station 120. The energy storage device 110 is designed to store electrical energy for operating an electric drive motor 103 of the vehicle 100.

[0033] The vehicle 100 includes a charging socket 101 (generally referred to as a charging interface) to which a corresponding (charging) plug 121 of a charging cable 122 can be plugged. The charging socket 101 and the plug 121 typically form a plug-in system. The charging cable 122 can be permanently connected to the charging station 120 (as shown). Alternatively, the charging cable 122 can be connected to the charging station 120 via a plug connection (e.g., for AC charging). As shown in Fig. 1, the charging socket 101 is attached to the vehicle 100. Various plug variants exist according to the plug standard IEC 62196-3: Combo 1, Combo 2, DC Type 1, DC Type 2.

[0034] The electrical energy storage device 110 can, as shown by way of example in Figures 2a and 2b, have a first partial storage device 201 and a second partial storage device 202. Furthermore, the energy storage device 110 can have one or more switching elements S3, S6, S7 (e.g. semiconductor-based switching elements and / or relays) which make it possible to arrange the partial storage devices 201, 202 in different arrangements, in particular in a serial arrangement (as shown in Fig. 2a) or in a parallel arrangement (as shown in Fig. 2b). A dashed line indicates that the respective switching element is open (and thus the corresponding electrically conductive connection is not present). On the other hand, a solid line indicates that the respective switching element is closed (and thus the corresponding electrically conductive connection is present).

[0035] Figures 2a and 2b also show switching elements S1, S2, which make it possible to couple the vehicle-external charging station 120 to the electrical energy storage device 110 or to decouple it from the energy storage device 110. Furthermore, Figures 2a and 2b also show an exemplary electrical load 200, which can be arranged in parallel with the charging station 120 and / or the energy storage device 110 or decoupled from it via the switching elements S4, S5.

[0036] The first partial storage device 201 and the second partial storage device 202 can each have a nominal voltage that indicates, for example, the voltage of the respective partial storage device 201, 202 when fully charged, i.e., at an SOC (state of charge) of 100%. When the partial storage devices 201, 202 are arranged in series, the energy storage device 110 has a total nominal voltage that corresponds to the sum of the nominal voltages of the partial storage devices 201, 202. On the other hand, when the partial storage devices 201, 202 are arranged in parallel, the energy storage device 110 has a total nominal voltage that corresponds to the nominal voltage of one partial storage device 201, 202.

[0037] The charging station 120 can have a first charging voltage with a value between the nominal voltage of the individual partial storage units 201, 202 and the total nominal voltage of the serial arrangement of the partial storage units 201, 202.

[0038] As a result, the energy storage device 110 cannot be fully charged by the charging station 120 in the serial arrangement. On the other hand, a charging process of the energy storage device 110, which is carried out entirely in the parallel arrangement of the partial storage devices 201, 202, would be relatively slow due to a reduced (second) charging voltage.

[0039] A (control) device 250 for controlling a charging process can be designed

[0040] • in a first phase of the charging process, to charge the energy storage device 110 in the serial arrangement of the partial storage devices 201, 202 (with a relatively high first charging voltage); and

[0041] • when a voltage threshold value is reached, to charge the energy storage device 110 in the parallel arrangement of the partial storage devices 201, 202 in a second phase of the charging process (with a second charging voltage reduced compared to the first charging voltage).

[0042] Fig. 3 shows an exemplary temporal profile of the voltage 300 at the energy storage device 110 during a charging process. In a first phase 331 up to time 305, the energy storage device 110 is charged in the serial arrangement. In the serial arrangement, the energy storage device 110 has the total serial nominal voltage and can be charged with the first charging voltage 310 of the charging station 120, which in the example shown is lower than the total nominal voltage of the serial arrangement. In the first phase 331, the (storage) voltage 300 at the energy storage device 110 increases according to the profile 301.

[0043] When the voltage 300 at the energy storage device 110 in the serial arrangement reaches a certain voltage threshold 311, the energy storage device 110 can be transferred from the serial arrangement to the parallel arrangement in order to fully charge the partial storage devices 201, 202 of the energy storage device 110. The voltage threshold 311 can depend on the first charging voltage 310 of the charging station 120. In particular, the voltage threshold 311 can be below the first charging voltage 310 by a certain offset value or by a certain percentage (e.g., between 5 and 10%).

[0044] After switching from the serial arrangement to the parallel arrangement, the energy storage device 110 can be fully charged in the second phase 332 until the nominal voltage of the partial storage devices 201, 202 is reached using a second charging voltage 320. This results in the voltage curve 302.

[0045] Switching the energy storage device 110 from the serial arrangement to the parallel arrangement should not lead to an interruption of the charging process. For this purpose, one or more electrical consumers 200 can be used as a load to absorb the charging power provided by the charging station 120 during the switching process. In particular, one or more switching elements S4, S5 can be closed during the switching process in order to arrange the one or more electrical consumers 200 in parallel with the charging station 120. In this way, switching from the serial arrangement to the parallel arrangement of the energy storage device 110 can be effected without interrupting the charging process. As explained above, it may happen that a charging station 120 cannot fully charge the battery 110 (i.e., the energy storage device) of an electric vehicle 100 due to a limited voltage level.For example, a vehicle 100 with battery voltage limits Umin = 350V and Umax = 800V can only be charged up to 750V and therefore not fully charged by a charging station 120 with voltage limit Umax = 750V.

[0046] To still enable full charging, a transition between 800V charging (with a first charging voltage of 310V of 800V) and 400V charging (with a second charging voltage of 320V of 400V) can occur during the ongoing charging process. During this transition, the on-board network voltage (i.e., the storage voltage 300V) can be supported by one or more HV (high-voltage) consumers 200 of the vehicle 100.

[0047] During the charging process (e.g. by a control device 250 of the vehicle 100), a transition to a charging process with a reduced charging voltage can be effected by the following process:

[0048] • The vehicle 100 requests a specific charging current (e.g., 5A) or a specific charging power (with the first (relatively high) charging voltage 310) at the charging station 120. Thus, in the first phase 331 of the charging process, the energy storage device 110 can be charged (relatively quickly) in the serial arrangement.

[0049] • To switch from the serial arrangement to the parallel arrangement, the vehicle 100 requests the one or more electrical consumers 200 (e.g. an air conditioning system, the electric drive machine 103, etc.) to provide a specific load current (e.g. 5V) and / or a specific load power (with the first (high) on-board network and / or charging voltage 310).

[0050] • As soon as the one or more consumers 200 act as an electrical load for the charging station 120, the electrical energy storage device 110 can be decoupled from the charging station 120. In particular, the serial arrangement of the partial storage devices 201, 202 can be interrupted by opening the switching element S3.

[0051] • The charging station 120 can then be requested to reduce the charging voltage to a second (reduced) charging voltage 320. The second (reduced) charging voltage 320 can, for example, correspond to the nominal voltage of the partial storage units 201, 202. The on-board electrical system voltage (ie, the storage voltage 300) of the vehicle 100 is (automatically) reduced in accordance with the reduction in the charging voltage.

[0052] • As soon as the vehicle electrical system voltage is adjusted to the reduced charging voltage, the first partial storage 201 can be connected in parallel to the charging station 120 (by closing the switching element S7).

[0053] • The one or more electrical consumers 200 can then be prompted to reduce the load current to 0A.

[0054] • Furthermore, the second partial memory 202 can be switched on (by closing the switching element S6) (in order to effect the parallel arrangement of the partial memories 201, 202).

[0055] Fig. 4 shows a flowchart of a (possibly computer-implemented) method 400 for controlling a charging process of an electrical energy storage device 110 (in particular an electrochemical energy storage device, such as a lithium-ion-based energy storage device) of a (motor) vehicle 100 at a vehicle-external charging station 120. The energy storage device 110 comprises a first partial storage device 201 and a second partial storage device 202, which can be arranged (by one or more switching elements S3, S6, S7) both in a serial arrangement and in a parallel arrangement.

[0056] The method 400 comprises charging 401, in a first phase 331 of the charging process, the energy storage device 110 with the serial arrangement of the first partial storage device 201 and the second partial storage device 202 (in which the series connection of the first and second partial storage devices 201, 202 is arranged in parallel with the charging station 120). Charging 401 in the first phase 331 can be performed with a first charging voltage 310.

[0057] The method 400 further includes effecting 402 a switching process in which the first partial storage device 201 and the second partial storage device 202 are transferred from the serial arrangement to the parallel arrangement (wherein the parallel arrangement, the parallel connection of the first and second partial storage devices 201, 202 is arranged parallel to the charging station 120). The switching process is carried out in such a way that the charging process is not interrupted by the switching process. For this purpose, one or more electrical consumers 200 can be temporarily used as an electrical load for the charging station 120 (in order to act as an electrical load for the charging station 120 instead of the energy storage device 110).

[0058] The method 400 further comprises the (continued) charging 403, in a second phase 332 of the charging process, of the energy storage device 110 with the parallel arrangement.

[0059] The measures described in this document can be used to conveniently effect a continuous charging process to fully charge an electrical energy storage device 110.

[0060] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and figures are intended only to illustrate the principle of the proposed methods, devices, and systems by way of example.

Claims

Claims 1) Device (250) for controlling a charging process of an electrical energy storage device (110) of a vehicle (100) at a vehicle-external charging station (120); wherein the energy storage device (110) comprises a first partial storage device (201) and a second partial storage device (202); wherein the device (250) is configured, - in a first phase (331) of the charging process, to charge the energy storage device (110) with a serial arrangement of the first partial storage device (201) and the second partial storage device (202); - to effect a switching process in which the first partial memory (201) and the second partial memory (202) are converted from the serial arrangement into a parallel arrangement; and - in a second phase (332) of the charging process, to charge the energy storage device (110) with the parallel arrangement. 2) Device (250) according to claim 1, wherein the device (250) is configured to cause one or more electrical consumers (200) to provide an electrical load for the charging station (120) during the switching process, in particular instead of the energy storage device (110). 3) Device (250) according to claim 2, wherein the one or more electrical consumers (200) comprise an electric drive machine (103) of the vehicle (100) and / or an air conditioning system of the vehicle (100). 4) Device (250) according to one of the preceding claims, wherein the device (250) is arranged to cause the charging station (120), - to charge the energy storage device (110) in the first phase (331) of the charging process with a first charging voltage (310); and - to charge the energy storage device (110) in the second phase (332) of the charging process with a second charging voltage (320); wherein the second charging voltage (320) is smaller than the first charging voltage (310). 5) Device (250) according to claim 4, wherein the device (250) is arranged, during the switching process, - causing one or more electrical consumers (200) to provide an electrical load for the charging station (120); - when the electrical load is caused by the one or more electrical consumers (200), to decouple the first partial storage (201) and the second partial storage (202) from the charging station (120); and - when the first partial storage device (201) and the second partial storage device (202) are decoupled from the charging station (120), to cause the charging station (120) to reduce the charging voltage for the charging process from the first charging voltage (310) to the second charging voltage (320). 6) Device (250) according to claim 5, wherein the device (250) is arranged, during the switching process, - when the charging voltage has been reduced to the second charging voltage (320), to couple the first partial storage (201) to the charging station (120); and - when the first partial storage device (201) has been coupled to the charging station (120), to cause one or more electrical consumers (200) to no longer cause the electrical load for the charging station (120). 7) Device (250) according to claim 6, wherein the device (250) is configured to connect the second partial storage (202) in parallel to the first partial storage during the switching process when the electrical load is no longer caused by the one or more electrical consumers (200). Part storage (202) with the charging station (120) to couple the parallel To effect arrangement of the first partial memory (201) and the second partial memory (202). 8) Device (250) according to one of claims 4 to 7, wherein the device (250) is arranged - to detect during the first phase (331) of the charging process that a storage voltage at the electrical energy storage device (110) is equal to or greater than a voltage threshold value (311); wherein the voltage threshold value (311) depends in particular on the first charging voltage (310), being approximately between 2% and 10% below the first charging voltage (310); and - to cause the transition process in response to the detection. 9) Device (250) according to one of claims 4 to 8, wherein - the first partial storage (201) and the second partial storage (202) each have a nominal voltage; - the first charging voltage (310) is less than, e.g., 5% or more less than, the sum of the nominal voltages of the first partial storage device (201) and the second partial storage device (202); and - the second charging voltage (320) is equal to or greater than the nominal voltage of the first partial storage (201) and / or the second partial storage (202). 10) Device (250) according to one of the preceding claims, wherein the device (250) is arranged to effect the switching process in such a way that - the charging process is not interrupted by the switching process; and / or - the first partial memory (201) and the second partial memory (202) are transferred from the serial arrangement to the parallel arrangement during the ongoing loading process; and / or - the second phase (332) of the charging process follows the first phase (331) of the charging process without user intervention. 11) Method (400) for controlling a charging process of an electrical energy storage device (110) of a vehicle (100) at a vehicle-external charging station (120); wherein the energy storage device (110) comprises a first partial storage device (201) and a second partial storage device (202); wherein the method (400) comprises, - charging (401), in a first phase (331) of the charging process, the energy storage device (110) with a serial arrangement of the first partial memory (201) and the second partial memory (202); - effecting (402) a switching process in which the first partial memory (201) and the second partial memory (202) are transferred from the serial arrangement into a parallel arrangement; and - charging (403), in a second phase (332) of the charging process, the Energy storage device (110) with the parallel arrangement.

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